WIND TURBINE PILLOW BLOCK BEARING ASSEMBLY CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application of, and claims priority to, US App. No. 60/974,198 filed September 21 , 2008. In addition, this application is related pending application Ser. No. 1 1/817789 filed September 4, 2007 which is the US National Phase of International App. No. PCT/US2006/008359 (published as WO2006099014) having an international filing date of March 9,2006 and which claims priority to US Provisional App. No. 60/659,805 filed March 9, 2005. All of the noted applications are incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable. TECHNICAL FIELD This invention relates to bearing assemblies for wind turbines, and, in particular, to a wind turbine bearing assembly having cones, or inner races with two rows of inwardly directed tapered rollers and a double cup or outer race having a spherical outer surface (referred to herein as a TDODA bearing assembly) and an anti-friction liner which can be serviced up-tower (i.e., at the top of the support tower).

BACKGROUND OF THE INVENTION

Wind turbines comprise a support tower on which a housing is mounted. With reference to FIG. 1 , the housing contains a gear box GB and a bearing assembly BA. Typically, the bearing assembly has been a spherical roller bearing (SRB) assembly. The gear box and bearing assembly support a shaft S, which extends out of the housing. A nose cone NC is mounted to the end of the shaft S, and rotor blades B are mounted to the nose cone. As is known, wind acting on the blades B causes the blades, and hence, nose cone NC and the shaft S to rotate. The shaft S drives a series of gears within the gear box GB, which, in turn, drive a generator to produce electricity.

To date, the wind industry has not been successful in its application of the SRB main shaft pillow block assemblies as it relates to reliability and service life. The SRB bearing assemblies currently typically installed in wind turbines must operate with internal clearance. The internal clearance combined with the unsteady wind loads applied to the bearing assembly (through the shaft), causes the bearings to fail prematurely - long before the design service life for the bearing assembly. When these bearings fail, a very large and expensive crane must be used to pull the entire drive train from the wind turbine so that a replacement SRB may be installed. Once the new bearing is installed, the drive train is replaced.

In my above noted application (published as WO2006099014), I disclose a TDODA, tapered roller bearing assembly incorporating inwardly directed tapered rollers, seals and anti-friction liner bushings. As described therein, the anti-friction liner bushings in the bearing assembly substantially eliminate the effect of overturning moments, both internal to the TDODA bearing assembly and external to the support mounting structure, thereby giving the tapered roller bearing portion of the TDODA bearing assembly a substantially longer operational life. However, the seals and anti-friction liner bushings in the TDODA bearing assembly may still need servicing. Therefore, it would be desirable to provide a bearing assembly that could be serviced "up-tower" to substantially eliminate the need for wind turbine operators to rent cranes at great expense. Rather, the operators could schedule regular maintenance for the wind turbine bearing assembly, as the seals and anti-friction liner bushings typically experience slow wear out failures as opposed to rolling element seizure failure as can occur with a rolling element bearing in an improperly designed or maintained application. BRIEF SUMMARY OF THE DISCLOSURE

As will become clearer below, a pillow block assembly made in accordance with the claims below allows for one or more of the following: (1 ) up-tower replacement of its seals; (2) up-tower replacement of its anti-friction

lining; (3) up-tower access to the bearing chamber to allow for inspection of the bearing chamber and removal of hardened and dried grease from the bearing chamber; (4) separation of the ball/socket interface from the bearing chamber; and (5) a grease by-pass to enable grease to by-pass a tight fitting labyrinth seal which is sized to substantially prevent the passage of grease through the labyrinth seal.

A pillow block assembly comprise a pillow block housing having a housing body, an upwind end plate and a downwind end plate. The end plates are removably mounted to the housing body, and the housing body defining a generally cylindrical bore.

An anti-friction liner assembly is removably received in the housing and is comprised of an upwind section and a downwind section. Each section of the liner assembly comprises a cylindrical outer surface sized and shaped to be received within the housing body bore and a part spherical inner surface. In accordance with one aspect of the invention, the housing body can include a counterbore on at least one axial end of the body, and at least one of the liner sections comprises a radial flange sized to be received in the counterbore. The Miner flange will then be sandwhiched between the housing counterbore and the endplate to frictionally rotationally fix the liner section in the housing body. The more securely fix the position of the liner section relative to the housing, the liner section flange can be provided with a plurality of bolt holes aligned with bolt holes in the housing body counterbore. The liner section can then be secured to the housing body by means of fasteners, such as bolts. The liner flange can be narrower in axial depth than the width of the housing counterbore. In this instance, the pillow block assembly can include an adjustment mechanism to adjust the axial position of the liner section so that the upwind liner section can be adjusted for wear or thermal compensation. Such an adjustment mechanism can be a manual adjustment (such as a fastener) or an automatic adjustment (such as a biasing element).

Finally, the each liner section can be comprised of a plurality of liner segments.

A bearing assembly is received within the anti-friction liner assembly. The bearing assembly comprises inner races through which a wind turbine shaft can pass, an outer race, and two rows of inwardly directed tapered rollers. The outer race has a spherical outer surface sized and shaped to be received within the liner assembly. The bearing assembly defines a bearing chamber which receives grease. Additionally, the bearing assembly and liner assembly, in combination, define an outer race/liner interface or ball/socket interface.

A seal carrier is mounted about the shaft, adjacent the bearing assembly inner race. In one embodiment, the end plate has an inner radial end proximate an outer radial surface of the seal carrier. The seal carrier carries a ring seal which seals against an axial outer surface of the end plate. A labyrinth seal formed in part by the seal carrier, and has an inner end proximate the bearing chamber and an outer end at an outer surface of the pillow block assembly. The ring seal seals the outer end of the labyrinth seal.

At least one of the end plates is removable at least in part from the housing to gain access to the liner assembly to enable servicing/ replacement of the liner assembly without removal of the bearing assembly from the housing.

In one embodiment of the pillow block assembly, the labyrinth groove is also defined in part by the end plates. In this embodiment, the seal carrier and the end plates comprise correspondingly shaped portions, which are positioned adjacent each other to define the labyrinth groove.

The labyrinth is a tight labyrinth, and is sized such that grease cannot readily pass through the labyrinth. To this end, the pillow block assembly can further include a grease by-pass. The grease by-pass comprises a passage having an inner end in communication with the bearing chamber and an exit at an outer surface of the pillow block assembly. In one embodiment, the

grease by-pass is formed in the seal carrier, and the by-pass exit is closed by the ring seal.

In one embodiment, the pillow block assembly includes a ring secured to an axial outer end of the bearing outer race. The ring comprises an axial outer surface, a radial outer surface and a radial inner surface. The radial inner surface of the ring is proximate a radial outer surface of the seal carrier. The end plate has an inner surface corresponding to the ring axial outer surface. The end plate inner surface and the ring axial outer surface, in combination defining a second labyrinth seal therebetween having an inner end proximate the outer race/liner interface and an outer end proximate the ring seal; the ring seal sealing the labyrinth seal. Whereas the first labyrinth is a tight labyrinth, this second labyrinth is a loose labyrinth, and can accommodate angular and axial motion, in addition to radial motion. In this embodiment, both the first and second labyrinths are closed by a single ring seal.

In another embodiment, the seal carrier is a two-piece assembly, and comprising a radial inner ring and a radial outer ring. The radial inner ring surrounds the shaft and has an axial inner surface which abuts the inner race of the bearing assembly. The radial outer ring is secured to the radial inner ring and comprises a radial outer surface, a radial inner surface and an axial inner surface. The radial outer surface of the outer ring in conjunction with a radial inner surface of the end plate defining a second labyrinth seal having an inner end proximate the socket interface an outer end proximate and closed by the ring seal. This second labyrinth seal is a loose labyrinth seal. The radial outer ring further comprises an inner flange extending from the axial inner surface along a radial inner surface of the bearing outer race. The flange in conjunction with the bearing outer race defines the first, tight, labyrinth seal. In this embodiment, the first labyrinth has an inner end which is in communication with the bearing chamber and a second end which is in communication with the second labyrinth seal via a gap between an end face

of the bearing assembly outer race and the inner surface of the seal carrier radial outer ring.

This just noted embodiment can be provided with up to three bypass paths which extend through the radial outer ring. The first grease bypass path provides communication between the bearing chamber and a by-pass exit closed by the ring seal; the second grease bypass path provides communication between the outer race/liner (or socket) interface and the bypass exit, and the third grease bypass path to place the first labyrinth in communication with the ring seal. The first grease bypass path comprises a main passage extending from an axial inner surface of the outer ring to a radial outer surface of the radial outer ring and a lower passage extending from an inner radial surface of the radial outer ring to the main passage. The main passage is closed at the ring radial outer surface by the ring seal. The second grease bypass path comprises the main passage and an upper passage extending from the outer ring radial outer surface to the main passage. The main passage is blocked at its axial inner end by a plug. The third grease bypass path comprises the main passage.

To facilitate access to the bearing chamber and the anti-friction liner, at least one of the endplates, in accordance with one aspect of the invention, comprises a radial inner section and a radial outer section which are mechanically and removably connected together approximate a junction of the radially inner and outer endplate sections. The radially outer endplate section is removably secured to the housing body, and the ring seal seals against the radially inner endplate section. The endplate radially outer section can be removed to allow access to the anti-friction liner and the bearing chamber.

In another embodiment which will allow access to the anti-friction liner and the bearing chamber, the seal carriers are rotating seal carriers, and the pillow block assembly further includes static seal carrier positioned between the rotating seal carriers and the endplates. The static seal carrier is removably fixed to an end face of the bearing outer race, and carriers a

second, outer seal; the outer seal sealing against an axial outer surface of the endplate. The ring seal carried by the rotating seal carrier thus comprises an inner ring seal which seals against the axial outer surface of the static seal carrier. The inner and outer seals can both be V-ring seals. In alternative embodiments, the outer seal can comprise a membrane which is secured at one end to a surface of the static seal carrier and secured at an other end to a surface of the endplate or, the outer seal can have a fixed end and a free end in which the fixed end is secured to the static seal carrier or the end plate and the free end seals against the bearing outer race, the static seal carrier, or the end plate.

The static seal carrier comprises a radial inner surface, a radial outer surface, an axial inner surface and an axial outer surface. The axial inner surface defines an inner diameter of the static seal carrier which is larger than an outer diameter of the rotating seal carrier. Additionally, the radial outer surface of the static seal carrier defines a diameter that is less than the inner diameter of the end plate. The dimensions of the static seal carrier relative to the rotating seal carrier and the end plate allow for the static seal carrier to be removed from the pillow block assembly to allow for access to the bearing chamber. In accordance with another aspect of the pillow block assembly, the pillow block assembly includes a separator ring having an axial inner edge adjacent bearing assembly outer race and which separates the socket interface from the bearing chamber to substantially prevent the passage of grease and/or particulate matter between the socket interface and the bearing chamber. In the embodiment described above, in which the pillow block assembly comprises a rotating seal carrier and a static seal carrier, the static seal carrier, which is fixed to the end face of the outer race, comprises the separator ring. In the first described single-seal embodiment, wherein the end plate axially surrounds a ring secured to the end face of the outer race to define the second labyrinth, the ring secured to the outer race end face forms

thθ separator ring. Lastly, in the embodiment wherein the carrier is a two-part assembly, the separator ring is comprised of the radial outer ring of the carrier (which in combination with the radial inner surface of the end plate and the end face of the outer race defines the second and first labyrinth seals). BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic of a wind turbine drive train;

FIG. 2 is a cross-sectional view of a typical pillow block SRB assembly (i.e., an OEM pillow block assembly)

FIG. 3A is a cross-sectional view of the TDODA pillow block assembly described in WO2006099014;

FIG. 3B is a cross-sectional view of an alternative TDODA pillow block assembly which illustrates a cylindrical OD anti-friction liner for retrofit usage of existing SRB pillow block housings as well as a dual direction labyrinth ;

FIG. 4 is a cross-sectional view of a TDODA pillow block assembly which is a direct replacement for an SRB bearing assembly;

FIG. 4A is a cross-sectional view of a variation of the pillow block assembly of FIG. 4, having greater axial load capacity on the anti-friction liners;

Fig. 5 is a cross-sectional view of a first illustrative embodiment of a pillow block assembly which allows for "up tower" maintenance of the assembly;

FIG. 5A is a cross-sectional view of a variation of the pillow block assembly of FIG. 5, which obviates the need to disturb or adjust the bearing locknut during anti-friction liner replacement; FIG. 6 is a cross-sectional view of a pillow block assembly similar to that of FIG. 5A, but which has an OD rib or flange on the anti-friction liner which is pinched by the down wind end cover to assist in anti-rotation of the anti-friction liner;

FIGS. 6A and 6B show variations to the pillow block assembly of FIG. 6, illustrating a bolt circle for anti-friction liner retention and anti-rotation;

FIGS. 7A-B are cross-sectional views of variations of pillow block assemblies with up-tower maintenance capability and cup mounted seal rings, tight labyrinth gaps and shaft ring mounted grease by-pass for removal of dried/old lubricant; FIG. 8 is a cross-sectional view of a pillow block assembly similar to that of FIGS. 7A-B, but wherein the function of the downwind seal carrier is provided by the lock nut, and a grease by-pass is incorporated into the lock nut;

FIG. 9 is a fragmentary cross-sectional view of the upwind side of the pillow block assembly showing a single seal version of an outer bearing ring (cup) mounted seal ring;

FIG. 10 shows a fragmentary cross-sectional view of a single seal version of a tight sealing labyrinth referenced to the outer bearing race (cup) but without requiring threaded holes in the cup, the seal carrier illustratively showing all passages used to form grease by-pass routes;

FIGS. 10A-C are cross-sectional views similar to that of FIG. 10, but with the ring seal removed, and showing the three by-pass routes formed from sub-combinations of the passages in the carrier shown in FIG. 10;

FIG. 1 1 shows a further seal and labyrinth variation for oil lubrication of the tapered roller bearing and separate oil lubrication of the anti-friction liners;

FIG. 12 shows another seal/labyrinth configuration, and demonstrates the seal movement due to relative movement of a static seal carrier relative to the pillow block housing;

FIG. 13 shows a further seal/labyrinth configuration and a two-piece shaft ring including a rib on an radial inner member and a radial outer member which is removably mounted to the rib of the radial inner member; the external seal being positioned on this removable radial outer member of the two-piece shaft ring, Fig.10 being derived from this concept;

FIGS. 14 and 14A show another seal/labyrinth configuration, derived from the configuration of Fig. 13, which demonstrates the seal movement due

to relative movement of a static seal carrier relative to the pillow block housing;

FIGS. 15 and 15A show yet another seal/labyrinth configuration, a spherical surface extension concept, and which demonstrate the seal movement due to relative movement of a static seal carrier relative to the pillow block housing. Also shown is a removable seal mounting bushing which when removed, provides access to a rib for shaft ring removal; and

FIG. 16 shows an alternative embodiment of an upwind insert/liner including a anti-rotation means and a preloaded spring member in a liner "keeper" pocket to adjust the liner for wear;

Corresponding reference numerals will be used throughout the several figures of the drawings. DETAILED DESCRIPTION OF THE INVENTION

The following detailed description illustrates the invention by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what I presently believe is the best mode of carrying out the invention. Additionally, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

A typical OEM SRB pillow block assembly 100 is shown in FIG. 2. The assembly 100 comprises an upwind seal carrier ring 1 10a and a downwind seal carrier ring 1 10b which sandwich an SRB bearing 1 12. The construction of an SRB bearing is well known, and, therefore, the SRB bearing is shown only schematically in FIG. 2. The seal carrier rings 1 10a,b and the bearing

1 12 are mounted about the wind turbine main shaft 1 14 and held in place against a shoulder 1 16 of the shaft by a lock nut 1 18. The seal carriers 1 10a,b each include an axially inwardly extending finger 120a,b and an radially outwardly extending flange 122a,b. The seal carriers 1 10a,b sandwich the inner race of the SRB bearing.

A pillow block housing 124 radially surrounds the SRB bearing 1 12. The pillow block housing 124 includes a radially inwardly directed rib 125 on its downwind side, which engages the outer race of the SRB bearing. Upwind and downwind end covers 126a,b are secured to the axial faces of the housing 124 by means of threaded fasteners 128a,b, such as bolts, arranged in a bolt circle. The end plates 126a,b include axially extending shoulders 130a,b on which radial inner surfaces of the pillow block housing 124 rest. The shoulder 130a of the upwind end plate extends to engage the upwind side of the outer race of the SRB bearing 1 12, such that the outer race of the SRB bearing 1 12 is sandwiched and axially constrained between the upwind end plate 126a and the housing rib 125. The end plates 126a,b each define an axially extending outwardly facing groove 132a,b near the bottom of the plates and which is aligned with, and sized to receive, the inwardly extending fingers 120a,b of the seal carrier rings 1 10a,b. The engagement of the end plates 126a,b with the seal carriers 1 10a,b defines a labyrinth seal 134a,b on each side of assembly 100. Lastly, the assembly 100 includes seals 136a,b (shown to be V-ring seals) which rest on axially radially extending surfaces of the seal carriers 1 10a,b between the flanges 122a,b and the respective end plates 126a,b to seal against the end plates 126a,b thereby sealing the exit of the labyrinth seals 134a,b.

In operation the wind can apply axial, radial and moment forces to the shaft 1 14. The SRB bearing 1 12 supports these external forces and moments only with axial and radial force reactions. The SRB bearing does not support or create moment reactions and so must support external application moment loads with radial reactions, in a moment couple with the gearbox input shaft

carrier support bearings. However for reasons related to SRB bearing internal geometry, the SRB bearing 1 12 does not successfully support the highly fluctuating axial loads over a long period of time in a successful manner, causing premature SRB bearing failure. The TDODA pillow block assembly 200 shown in FIG. 3A shows the pillow block assembly disclosed in published PCT application WO2006099014, which is incorporated herein by reference. As noted above, a TDODA bearing assembly is a bearing assembly having cones, or inner races, with two rows of inwardly directed tapered rollers and a double cup or outer race having a spherical outer surface. The pillow block assembly 200 includes a double-row tapered roller bearing assembly 212 comprising inner races 214 having axial bores through which the main shaft S passes and an outer race 216. The inner and outer races 214 and 216 define inner and outer raceways, and the bearing assembly 212 includes a set of inwardly-directed tapered rollers 218 positioned between the inner and outer raceways. The bearing assembly 212 defines a bearing chamber 249b which receives grease to lubricate the bearing assembly. The outer race 216 defines a spherical outer surface 216a. It will be apparent that the outer surfaced defined by the outer race does not form a full sphere. Thus, what is meant by "spherical outer surface" is that the outer race defines a sphere that is truncated at the outer faces of the race.

A pillow block housing assembly 224, configured for attachment to a stationary support structure, radially surrounds the bearing assembly 212. The pillow block housing assembly 224, as illustratively shown, includes a body member 226 and a clamp member 228. The body member 226 has a downwind inner surface 226a which defines a spherical surface and an upwind inner surface 226b which defines a cylindrical surface or bore. The clamp member 228 comprises a flange 228a which is bolted to the body member 226 and a cylindrical portion 228b extending axially from the flange. The cylindrical portion 228b has a cylindrical outer surface 228c sized and

shaped to be received within the cylindrical bore of the upwind portion 226b of the body member 226 and a spherical inner surface 228d. The curvature of the clamp member spherical surface 228d and the body spherical surface 226a are complimentary and define a continuous spherical surface when the clamp member 228 is mounted to the body 226. The spherical inner surfaces of the clamp member and body, in combination, define a socket surface shaped complementarily to the outer surface 216a of the bearing outer race 216.

An anti-friction liner or surface 230 is formed on the socket surface. The anti-friction liner 230 can be a lining that is applied to the inner surfaces 226a and 228d of the body and clamp member. Alternatively, the clamp member and/or the body member can be made of anti-friction material. The bearing assembly 212 is supported in the pillow block housing assembly 224 by the anti-friction liner 230 and is movable within and with respect to the pillow block housing assembly 224, such that the outer race 216 will move with angular movement of the shaft S and inner races 214 thereby reducing the transfer of overturning moments to the rolling elements 218 and the pillow block housing assembly 224. The outer surface of the bearing assembly outer race and the liner inner surface, in combination, define an outer race/liner (or socket) interface 249a.

The spherical outer surface of the outer race 216 allows for the bearing assembly 212 to move relative to the housing assembly 224 as the shaft moves or pivots relative to the pillow block assembly 200. This provides a degree of freedom which keeps the inner race and outer race aligned and substantially eliminates moment loads. Thus, the bearing assembly supports only axial and radial loads. As seen, a bore is formed in the top of the bearing outer race 216 and a pin 227 extends down through the housing body 226 into the bore. The pin and bore, as explained in the above noted published PCT application allow some movement of the bearing assembly 212 relative

to the housing; however, large relative movement of the bearing assembly 212 relative to the housing will be precluded.

The pillow block assembly 200 also includes rotating seal carriers 232a,b on opposite sides of the inner race elements 214. The upwind seal carrier rests against a shoulder (not shown in FIG. 3A, but shown in FIG. 3B) on the shaft S. A lock nut 234 on the shaft S holds the assembly in place relative to the shaft S and can set a pre-load on the inner race. Each of the rotating seal carriers 232a,b includes axially outwardly extending labyrinth seal fingers 236a,b which extend away from each other and a circumferential channel 238a,b in which elastomeric V-ring seals 240a,b ride. Second static seal carriers 242a,b are secured to opposite sides of the outer race element by means of fasteners 244 such as bolts, screws or the like. The static seal carriers 242a,b include second labyrinth seal fingers 246a,b which mesh with the first labyrinth seal fingers 236a,b to define labyrinth seals 248a,b adjacent each edge of the bearing assembly. Additionally, the static seal carriers include a flange which extends under the bearing assembly outer race to pilot the static seal carrier to the outer race so that the labyrinth will be rounded by the outer race and so that the static seal carriers will run 'true' with the rotating seal carriers 232a,b. Fastening the static seal carriers 242a,b tightly to the outer race 216, separates the outer race/liner (or socket) interface 249a from the bearing chamber or area 249b. This will prevent debris from the outer race/liner interface from entering the bearing chamber or area. The upwind static seal carrier 242a, as noted, is secured to the outer race element 216. It has an inner diameter that is greater than the largest outer diameter of the rotating seal carrier 232a,b, and thus can be removed from the outer race element to facilitate servicing of the bearing assembly. Additionally, the clamp 228 has an inner diameter that is larger than the largest outer diameter of the static seal carrier. The clamp, therefore, can be removed from the body without disturbing the seal carriers. The static seal carriers 242a,b each

includθ an upper surface bounded by a flange 250a,b which receives an elastomeric seal 252a,b.

The seals 240a,b which are mounted to the rotating seal carriers 232a,b seal against axial end faces of the static seal carriers 242a,b to exclude contaminates from the labyrinth seals. Additionally, the seals 252a,b which ride on the static seal carriers 242a,b seal against an edge surface of the pillow block housing assembly 224, or against an edge surface of the clamp member 228, adjacent the ball and socket interface to exclude contaminates from the ball and socket interface. In this pillow block assembly 200, the static seal carriers 242a,b are isolated from inner race element displacements and shaft rotations. Further, the rotating seal carriers 232a,b are isolated from angular displacements of the outer race element 216 relative to the pillow block housing assembly 224. Stated differently, this design separates angular tilt sealing and rotation sealing. It also separates the anti- friction surface and bearing environments.

An alternative pillow block assembly 300 is shown in FIG. 3B. The pillow block assembly 300 comprises a TDODA tapered roller bearing assembly 312 substantially identical to the tapered roller bearing assembly 212 of the pillow block assembly 200. The TDODA tapered roller bearing is retained on the shaft S by rotating seal carriers 332a,b and lock nut 334.

Static seal carriers 342a, b are fixed to the bearing assembly outer race via fasteners, such as bolts, screws or the like, which extend through holes in the static carriers 342a,b. The seal carriers 332a,b and 342a,b do not include intermeshing fingers to define a labyrinth seal between the carriers. Rather, the labyrinth seal is formed between the carriers by means of aligned grooves 344a,b. The seal carriers each carry V-ring elastomeric seals 340a,b and 352a,b.

The pillow block housing 324 of the assembly 300 comprises a body member 326 and upwind and downwind end plates 328a,b. The end plates 328a,b are secured to the body 326, for example, by fasteners, such as bolts,

screws or the like, (not shown) in a bolt circle. Spacers or biasing elements 329 can be positioned between the upwind end plate 328a and the upwind side of the body 326. Alternatively, the spacers or biasing elements 329 can be positioned between the upwind end plate 328a and the upwind anti-friction liner 330a. As seen, the body member 326 comprises a cylindrical inner surface 326a having a rib 326b at the downwind side of the body. Upwind and downwind anti-friction liner inserts 330a,b are received within the body 326. The inserts 330a,b each have a cylindrical outer surface sized to fit within the body 326 and a part spherical inner surface 331 . The upwind insert 330a has generally radially extending end edges. The downwind insert 330b has a generally radially extending inner edge which is spaced slightly from the axial inner edge of the upwind insert 330a to form a small gap. This gap allows for adjustment of the upwind liner due wearing of the liner surface. Adjustment of the position of the upwind liner can be performed, for example, by using set screws. The biasing element or spacer 329 facilitates axial placement and initial positioning of the upwind insert 330a. The downwind insert 330b defines a shoulder 334 at its outer end sized and shaped to mate with the body rib 326b, as seen in FIG. 3B. The inner surfaces 331 of the inserts define a substantially continuous spherical socket surface which is shaped to receive or fit about the spherical outer surface of the tapered roller bearing 312. The inner surfaces of the inserts may be coated with an antifriction coating or layer 334. Alternatively, the inserts 330a,b can be made from an anti-friction material. By providing an insert comprised of a backing or base to which a coating or layer of anti-friction material is applied allows for the use of materials which would not otherwise function as an anti-friction surface, thereby allowing the insert to have other properties that the antifriction material itself may not have. Each end plate 328a,b includes an inwardly directed flange 336a,b upon which the body 326 sits and which sandwich the inserts 330a,b.

Thθ anti-friction liner of the assemblies 200 and 300 are split into upwind and downwind sections. The downwind section supports a majority of the application loads. Axial thrust is in the horizontal downwind direction and forces due to weight are always directed vertically downward. Thus, the resultant force vector is down and back (i.e., in the downwind direction). A 4° typical downwind tilt of the drive train keeps the rotor blades from deflecting into the tower. This effectively adds 4° to the resultant force vector. The upwind liner section is basically a keeper. The spacer/biasing member 329 is adjustable to compensate for wear of the liner. The bias member in the location shown would be typically accomplished with a spacer shim. The spacer shim bias member may also be located between the end plate 328a and the upwind anti-friction liner 330a. At this interface location the biasing function can also take several different forms. It can include a bolt circle for a set screw adjustment, discrete multiple Belleville spring packs in counterbores; a single circumferential wavespring in a groove; or discrete multiple die springs in counterbores (as seen in FIG. 16). Additionally, if thermal compensation is not a large issue, an automatic one-way clutch, wear take-up mechanism may be employed.

The pillow block assembly 400 (FIG. 4) comprises a double taper roller bearing assembly 412 which is journaled about the turbine shaft S. The bearing assembly 412 is generally similar to the bearing assembly 212 (FIG. 3A) and is positioned in substantially identically to the bearing assembly 212. The inner race of the bearing assembly is sandwiched by an upwind seal carrier 410a and a downwind seal carrier 410b. The seal carriers 410a,b each include axially and inwardly extending labyrinth fingers 420a,b. The bearing assembly 412 is held in place by a housing assembly 424 comprising a housing body 426 and upwind and downwind end plates 428a,b which are secured to the body 426 via fasteners 429, such as threaded fasteners. The end plates 428a,b define a groove 432a,b which is aligned with, and receives, the labyrinth fingers 420a,b of the seal carriers 410a,b to define a labyrinth

seal between the end plates and the seal carriers. V-ring seals 436a, b are mounted on the seal carrier and seal against faces of the end plates 428a,b to prevent debris from entering the labyrinth seal.

The housing body 426 has a cylindrical inner surface and a radially extending rib 427 at its downwind side. The rib 427 is stepped as at 427a to provide an angular displacement clearance between the bearing assembly 412 and the end plate 428b. Upwind and downwind anti-friction liner inserts 430a, b are received in the body 426 and are sandwiched between a flange of the upwind end plate 428a and the body rib 427. As seen, the inserts 430a,b each have flat and generally radially extending end surfaces.

In the pillow block assembly 400, axial wind load is carried by the housing rib 427; the liners 430a,b are prevented from rotating relative to the housing body 426 by the fit with the upwind end cover and with the housing body, respectively. Alternatively, additional anti-rotation means such as pins or keys (such as shown in FIG. 3A) may be used if required. Because a single set of seals is used (as compared to the two seals of the embodiment shown in FIG. 3A), the anti-friction liner and the bearing 412 share lubricant and wear particles. That is, unlike the assembly 200 of FIG. 3A, the outer race/liner interface is not separated from the bearing assembly. In the pillow block assembly 400, the end cover 428b permits access to the downwind side of the bearing assembly if the bearing locknut and downwind seal carrier are backed off from the bearing assembly inner race. Further, in the assembly 400, the liners 430a,b are separate from the housing body 426 and the end plates 428a,b. They may be made from a uniform anti-friction material or may be comprised of a substrate or backing to which a layer or coating of an antifriction material is applied. The two liners both have a cylindrical outer diameter and a spherical inner surface. The downwind anti-friction liner 430b is a stationary locating reference; and the upwind anti-friction liner is axially adjusted for wear or thermal compensation. Once again, although not shown in FIG. 4, such axial adjustment can be accomplished by the use of shims or

biasing elements, such as is shown, for example, in FIG. 16. Finally, the assembly 400 does not permit replacement of the anti-friction liners 430a,b up-tower.

The pillow block assembly 400' of FIG. 4A is generally similar to the pillow block assembly 400 of FIG. 4. However, the housing body 426' has a shorter rib 427', and the downwind liner 430b' has a flange 431 which extends under the rib 427' to engage the downwind end plate 428b'. The bearing assembly of the pillow block assembly 400' is also axially wider than the bearing assembly of the pillow block assembly 400. The wider bearing assembly facilitates the ability for the anti-friction liner of the pillow block assembly to handle greater axial loads because the wider assembly increases the maximum contact angle between the spherical outer surface of the tapered roller bearing and the downwind liner 430b'.

As discussed in my above noted published PCT application, the assembly 200 solves many of the problems associated with the overturning moments such as occurs with the OEM assemblies 100, such as shown in FIG. 2. The assemblies 300, 400 and 400' provide variations of the assembly 200. In each of these designs, the upwind anti-friction liners require the addition of anti-rotation means such as pins or keys (not shown). The downwind anti-friction liner may also use these types of anti-rotation means but may also employ a tight fit design in the housing body bore to prevent rotation of the liner relative to the housing. In particular, the assemblies 300, 400 and 400' allow for the liners to be replaced upon wearing out. However, the design of these assemblies does not allow for "up-tower" replacement of the liners. In the pillow block assemblies discussed below, the assembly is designed to allow for "up-tower" replacement of the liner. Because the liners can be replaced "up tower" the need for the use of high performance/exotic (and thus expensive) materials for the anti-friction liner is eliminated. Rather, the owner/operator can have a regular maintenance schedule which replaces the liner at periodic intervals. For the replaceable designs discussed below,

thθ downwind anti-friction liners also require separate anti-rotation means as well as the upwind anti-friction liners, as a tight fit is not appropriate for an easy anti-friction liner replacement. Additionally, the requirement to be able to remove and replace the anti-friction liners up-tower requires that the liners be split or segmented so that they may be removed from over the shaft.

A first illustrative embodiment of a pillow block assembly 500 which allows for "up tower" maintenance is shown in FIG. 5. The pillow block assembly 500 (FIG. 5) comprises a TDODA double taper roller roller bearing assembly 512 which is journaled about the turbine shaft S. The bearing assembly 512 is substantially identical to the bearing assembly 412 (FIG. 4). The inner race of the bearing is sandwiched by an upwind seal carrier 510a and a downwind seal carrier 510b. The seal carriers 510a,b each include axially and inwardly extending labyrinth fingers 520a,b. The bearing assembly 512 is held in place by a housing assembly 524 comprising a housing body 526 and upwind and downwind end plates 528a,b which are secured to the body 526 via fasteners 529, such as threaded fasteners. The upwind end plate 528a comprises a radially inner section 528a-1 and a radially outer section 528a-2. The two sections have overlapping flanges, through which threaded fasteners 531 extend to secure the radially inner and outer sections of the end plate 528a together. An O-ring (not shown) is placed at the junction of the two sections to form a fluid-tight seal between the two end plate sections. The end plates 528a,b define a groove 532a,b which is aligned with, and receives, the labyrinth fingers 520a,b of the seal carriers 510a,b to define a labyrinth seal between the end plates and the seal carriers. V-ring seals 536a,b are mounted on the seal carrier and seal against faces of the end plates 528a,b to prevent debris from entering the labyrinth seal. On the upwind side of the assembly, the end plate groove 532a is formed in the radially inner section 528a-1 of the end plate 528a, and the V-seal 532a forms a seal between the seal carrier 510a and the end plate radially inner section 528a-1.

Thθ junction between the end plate radially inner and outer sections 528a-1 and 528a-2 is radially outside of the circumference (or greatest diameter) of the seal carrier 510a. This allows for removal of the radial outer section 528a-2 of the end plate 528a by removal of the fasteners 529 and 531 , and thus access to the upwind side of the pillow block assembly. As can be appreciated, with the radially outer section 528a-2 of the end plate 528a removed, the upwind liner section 530a can be removed and replaced, all without the need to remove the bearing assembly 512 or loosening the lock nut 518. Access to the downwind side of the pillow block assembly 500 is possible. However, in this design, access to the downwind side does require that the lock nut 518 be backed off.

The housing body 526 has a cylindrical inner surface defining a generally cylindrical bore. Upwind and downwind anti-friction liner inserts 530a,b are received in the body and are sandwiched between a flange of the upwind end plate 528a and a flange of the downwind end plate 528b. As seen, the liners 530a,b each have flat and generally radially extending end surfaces. Thus, it is seen that the entire thrust load imparted to the housing 526 is carried into the housing through the down wind circle of bolts 529, as the load carrying radial inward housing rib (i.e. rib 427 of assembly 400) has been removed to allow for the up-tower replacement of the anti-friction liner segments.

In the pillow block assembly 500' of FIG. 5A the end plates 528a and 528b' are both two piece end plates, and each comprises a radially inner section and a radially outer section. Thus, the pillow block assembly 500' allows access to both the upwind side and the downwind side of the assembly 500' without the need to back off the lock nut 518 from the pillow block housing. For this design, anti-rotation for the anti-friction liners can be accomplished with pins or keys, (not shown in FIG. 5A.)

In the pillow block assemblies 500 and 500', the anti-friction liners are sandwiched between the end plates. In the pillow block housing 600 (FIG. 6),

thθ end plates 628a,b are substantially the same as in FIG. 5A. The housing body 626, however, has a counterbore or shoulder 626a on its downwind side. The downwind anti-friction liner 630b has a flange 630b-1 which is received in the body counterbore 626a. As seen, the flange 630b-1 of the downwind anti-friction liner is sandwiched between the radially upper section of the downwind end plate 628b and the counterbore 626a of the body 626. This permits a pinching effect on the flange and provides an effective anti- rotation mounting for the downwind anti-friction liner 630b. By making the counterbore slightly larger, as seen at 626a' in FIG. 6A, the anti-friction liner can be secured in place in the housing body 626' by means of threaded fasteners 627.

In FIG. 6B, an upwind counterbore 626b is formed in the body 626", allowing for the upwind anti-friction liner to be secured to the body 626" by means of threaded fasteners extending through a flange 630a-1 . For the upwind liner, these fasteners may be used as anti-rotation means but may be arranged with a gap between the liner flange 630a-1 . Additionally, the liner flange 630a-1 is smaller in axial dimension than the counterbore formed in the upwind end of the body. This provides for a gap between the liner flange and the axial inner surface of the counterbore which is about equal in sized to the gap between the upwind and downwind liners. These gaps, permit axial adjustment of the upwind liner due wearing of the liner or to compensate for thermal expansion/contraction of the liner section.

The embodiments of FIGS. 5, 5A, 6, 6A and 6B all allow for access to the upwind and downwind sides of the pillow block assembly. The use of fasteners to secure the anti-friction liner in the housing of FIGS. 6A, 6B provides for a means to positively prevent the anti-friction liner from moving relative to the housing. As is clear from above, the anti-friction liner is formed in an upwind and a downwind section. For replacement, the upwind and downwind anti-friction liners are necessarily formed of at least an upwind and downwind section, which is split into at least a "C" section, allowing them to be

removed from around the solid main shaft. The use of fasteners to secure the liners in place as in FIGS. 6A-B, or even the pinching of the liner in place as in FIG. 6 allows for the liner sections (i.e., the upwind and downwind sections) to be formed from multiple segments. For example, the upwind and downwind liners could each be made of two segments (for a total of four), to allow the segments of each section to be removed from the shaft once the liner segments have been removed from the pillow block assembly. The use of anti-friction liners composed of multiple segments (i.e., more than two segments) allows for selective replacement of more heavily worn segments. In normal operation, the loads applied to the upwind and downwind antifriction liners are not equal. Thus, downwind segments will wear more quickly than the upwind segments. Additionally, the wear about the upwind and downwind anti-friction liners may not be equal. That is, for example, an upwind liner segment at a 12 o'clock position may receive more wear than an upwind liner at a 4 o'clock position. The split of the liner sections into segments further facilitates assembly of the pillow block housing and initial adjustment of the ball/socket (i.e., outer race/liner) fit at startup, as well as wear compensation adjustment prior to liner segment replacement. Additionally, once any given segment is completely worn, the segmented liner design allows for replacement of only the worn liner segment which needs replacing. Removal of the liner segments can be facilitated by the use of jack screws (not shown). Additionally, if the axial position of a particular liner segment needs readjustment due to wear, the position of the particular liner segment can be adjusted without the need to disturb the adjustment of the remaining segments of the liner section. Adjustment of liner segments can be done, for example, using biasing elements, set screws, etc.

For liners to be long lasting, they must be made from more exotic, and thus, more expensive, materials. Often, these long lasting materials will be composite materials. Such composite materials have thermal growth rates that are 1 Ox to 10Ox that of steel. The difference in thermal growth rates

creates a loading problem at the axial end of the bearing assembly, as clearance which is assumed to be due to wear may actually be due to thermal cycling. Thus, over loading of the ball socket fit could occur. If such composite materials were used for the anti-friction liners, the pillow block assembly would have to be designed to account for the thermal growth of the liners, and the loading that would occur due to such thermal growth. The use of segmented liners and pillow block assemblies which allow for up-tower access to the liners enables the liners or liner segments to be removed. This allows for the use of less expensive anti-friction materials, as the design of anti-friction liners that are not replaceable would potentially require exotic designs to insure sufficient life. While liners made from less expensive materials may not last as long as the more expensive materials, they permit the use of materials with reasonable properties for all of the desired requirements, instead of exotic materials with certain superior properties combined with other less desirable ones. For example, exotic materials usually have undesirable thermal characteristics related to thermal growth and thermal conductivity, unlike many more common anti-friction bushing materials.

The pillow block assemblies of FIGS. 4-6 all include a single pair of seals (i.e., one seal on each end of the pillow block assembly). The use of the single seal requires that the anti-friction liner and bearing assembly share lubricant and wear particles. Thus, particles from the outer race/liner interface can enter the bearing chamber. The pillow block assemblies of FIGS. 3A-B solve this problem by providing two seals on each side of the pillow block housing- one located essentially at the level of the rollers (i.e., a seal for the bearing) and the other essentially at the level of the interface between the bearing outer race and the anti-friction liner. The designs of FIGS. 3A-B permit up-tower replacement of the V-ring seals and up-tower access to used or dried grease. However these designs do not permit up-tower replacement of the anti-friction liners. The designs of FIGS. 5-6B overcome many of these

problems by allowing for both up-tower replacement of the seals and up-tower replacement of the anti-friction liners. However, as noted, the designs of FIGS. 4-6B do not separate the outer race/liner interface from the bearing chamber. Turning to FIG. 7A, a pillow block assembly 700 is shown which combines dual seal separation of the bearing and anti-friction liner areas with up-tower anti-friction liner replacement. The pillow block assembly 700 includes a TDODA double-row tapered roller bearing assembly 712 identical to the bearing assemblies 212 and 312 (FIG. 3A-B) through which the main shaft S passes. A pillow block housing assembly 724, configured for attachment to a stationary support structure, radially surrounds the bearing assembly 712. The pillow block housing assembly 724, as illustratively shown, includes a body member 726 and upwind and downwind end plates 728a,b which are mounted to the body 726 by fasteners, such as bolts 729, arranged in a circle. The body member 726 defines a bore having cylindrical surface 726a. Anti-friction liners 730a,b are received in the body bore. The antifriction liners 730a,b have cylindrical outer surfaces and spherical inner surfaces, and generally radially extending end surfaces. The liners 730a,b do not abut each other. This is true for all of the TDODA designs discussed. An adjustment gap is present between the liners in each of the embodiments discussed. For the assembly 700, the adjustment gap is designated 731 . The adjustment gap is provided between the liners to facilitate assembly of the pillow block assembly 700 and preload and wear adjustment of the ball socket fit between the bearing assembly 712 and the anti-friction liners 730a, b. Also an adjustment gap may occur between the upwind end cover and the upwind anti-friction liner for all of the designs other than FIG. 3A, where they are a single piece. The inner surfaces of the liners 730a,b, in combination, define a spherical surface which corresponds to the spherical outer surface of the outer race of the bearing assembly 712. The anti-friction liners 730a,b can comprise a backing or base to which an anti-friction coating

is applied. Alternatively, the liners 730a,b can be made of anti-friction material. The bearing assembly 712 is supported in the pillow block housing assembly 724 by the anti-friction liners 730a,b

Rotating seal carriers 732a,b are positioned on opposite sides of the inner race of the bearing assembly. An axial outer surface of the upwind seal carrier 732b abuts a shoulder of the wind turbine shaft S. A lock nut 734 and a hardened washer 735 on the shaft S bear against the axial outer surface of the downwind seal carrier 732b. The lock nut 734, as is known, allows for setting of a preload on the inner races of the bearing assembly. Static seal carriers 742a,b are secured to opposite sides of the outer race of the bearing assembly 712 by means of threaded fasteners 744. The static seal carriers 742a,b ride or are positioned on top of the rotating seal carriers 732a,b; that is, the rotating seal carriers 732a,b and static seal carriers 742a,b are coaxially arranged and have facing surfaces. Labyrinth seals 749a,b are formed between the seal carriers 742a,b and 732a,b. The seal carriers 732a,b and 742a,b each include channels or grooves 738a,b and 748a,b on axially extending, radially outer exterior surfaces thereof which receive V-ring elastomeric seals 740a,b and 752a,b. The seals 740a,b seal against axial outer faces of the static seal carriers 742a,b to seal the labyrinth seals to prevent particles from entering the labyrinth seals. The seals 752a,b seal against axial outer faces of the end plates 728a,b to seal the junction between the end plates and the static seal carriers 742a,b to prevent particles from entering the ball/socket (i.e., outer race/liner) interface. The static seal carriers, by way of being positively secured to the outer faces of the outer race, separate the outer race/liner interface from the bearing chamber to prevent grease and particulate material from the outer race/liner interface from entering the bearing chamber.

The rotating seal carriers 732a,b each include a grease by-pass passage 758 which is shown to be generally L-shaped. The passage 758 extends from an axial inner side of the seal carriers 732a,b to the channels

738a,b. Thus, the exit to the passages 758 is sealed by the V-ring seals 740a,b. The passages 758 place the bearing chamber in communication with the exterior of the pillow block assembly. As will be described below, the V- ring seals form a dynamic seal for the passages 758. A second set of passages 760 are defined by a gap between the radial outer surface of the static seal carriers 742a,b and the radial inner surfaces of the end plates 728a,b. The passages 760 extend between the junction of the outer surface of the outer race of the bearing assembly and the liners 730. The passages 760 place the ball/socket interface in communication with the exterior of the pillow block assembly. The passages 760 are sealed at their exits by the V- ring seals 752a,b. The inner portion of the V-ring seals 752a,b which seal the exits to the passages 760 is flexible.

The pillow block assembly 700' (FIG. 7B) is substantially the same as the pillow block assembly 700. The pillow block assembly 700', however, is provided with a housing body 724' and anti-friction liners 730a' and 730b' which are substantially the same as the body 626" and liners 630a,b of FIG. 6B. The embodiment of FIG. 7B thus facilitates the use of segmented liner sections, as discussed above in conjunction with FIGS. 6-6B.

In operation, the passage or grease by-pass 758 will be filled with grease. Should either of the seals 740a,b fail, the grease in the by-pass 758 will prevent contaminates from entering the housing 700. The same, of course, would be true for the passages 760. During lubrication, the grease in the by-pass 758 can be cleaned out simply by removing the seal 740a,b as necessary and using an appropriate plunger to remove grease from the passage. The grease by-pass 758 also allows for grease expulsion during a regreasing operation. Typical current SRB design labyrinths (such as shown in FIG. 1 ) are loose fitting. These loose fitting labyrinths are ineffective as seals, but are effective in allowing for grease expulsion. The designs disclosed herein have tight fitting labyrinths which are effective as seals. That is, the clearance or gap defined by the labyrinth seals 749a,b is too small to

permit grease to pass therethrough. Thus, the tight fitting labyrinths 749a,b do not readily allow for grease expulsion during lubrication. The passages 758 and 760 therefore by-pass the labyrinths to allow for grease expulsion during lubrication. The V-ring seals act as manual "valves" to block grease escape, or contaminant entry, during normal operation. However, during a lubrication maintenance procedure, the V-ring seals (which are flexible) can be pulled back (or otherwise removed) to allow for high bypass flow through the passage 758. Sufficient internal pressure would also allow for the V-seal to act as an "automatic valve" (i.e., the internal pressure would urge the grease out the passage, and the grease would push the V-seal aside). However, the normal intention would be for the V-ring dynamic seal to be pulled back manually to reduce back pressure developed in the assembly 700 during lubrication.

The pillow block assembly 800 (FIG. 8) is generally similar to the pillow block assembly 700 (FIG. 7A). The pillow block assembly 800 includes a TDODA double-row tapered roller bearing assembly 812 identical to the bearing assembly 212 (FIG. 3A) through which the main shaft S passes. A pillow block housing assembly 824, configured for attachment to a stationary support structure, radially surrounds the bearing assembly 812. The pillow block housing assembly 824, as illustratively shown, includes a body member 826 and upwind and downwind end plates 828a,b which are mounted to the body 826 by fasteners (not shown) arranged in a bolt circle. The body member 826 defines a bore having cylindrical surface 826a. The upwind end plate has a counterbore 828a-1 at its radial inner end. The radial outer edge of the counterbore is approximately flush with the radial inner surface 826a of the body 826. Anti-friction liners 830a,b are received in the body bore. The anti-friction liners 830a,b have cylindrical outer surfaces and spherical inner surfaces, and generally radially extending end surfaces. The downwind antifriction liner 830b extends beyond the mid-point of the body bore, and thus extends over the anti-rotation pin bore in the bearing assembly outer race.

Thθ upwind anti-friction liner 830a is sized such that an adjustment gap will exist between the radial inner ends of the upwind and downwind liners. Unlike in the prior pillow block assemblies, the adjustment gap between the upwind and downwind liners is off-center. The liners 830a,b have chamfered surfaces 831 at the axial outer ends of the inner surfaces of the liners. The downwind liner 830b has a flange which is received in a counterbore in the downwind side of the housing body 826 to enable the liner 830b to be fixed to the body 826 by threaded fasteners, as discussed above in conjunction with the assemblies of FIGS. 6AB. The upwind liner 830a extends beyond the axial outer edge of the body 826 and extends into the counterbore of the upwind end plate 828a, in order to pilot the endplate to facilitate assembly of the pillow block assembly 800.

Rotating seal carriers 832a,b are positioned on opposite sides of the inner race of the bearing assembly. An axial outer surface of the upwind seal carrier 832b abuts a shoulder of the wind turbine shaft S. Rather than using a separate downwind seal carrier and lock nut, the downwind seal carrier 832b is (or comprises) the lock nut. A hardened washer 835 is positioned on the shaft S between the inner race of the bearing assembly 812 and the axial inner surface of the lock nut/seal carrier 832b. Static seal carriers 842a, b are secured to opposite sides or faces of the outer race of the bearing assembly 812 by means of fasteners 844 (such as bolts, screws, or the like). Labyrinth seals 848a,b are formed between the seal carriers 842a,b and 832a,b. The seal carriers 832a,b and 842a,b each include channels or seats 838a,b and 849a,b on radially outer, axially extending surfaces which receive flexible V-shaped elastomeric seals 840a,b and 852a,b, respectively. The seals 840a,b seal against axial outer faces of the static seal carriers 842a,b to seal the labyrinth seals to prevent particles from entering the labyrinth seals. The seals 852a,b seal against axial outer faces of the end plates 828a,b to seal the junction between the end plates and the static seal carriers 842a, b.

Thθ rotating seal carriers 832a,b each include a grease by-pass passage 858 which is shown to be generally L-shaped. The passage 858 extends from an axial inner side of the seal carriers 832a,b to the channels 838a,b. Thus, the exit to the passages 858 is sealed by the V-seals 840a,b. As will be appreciated, the grease by-pass is to enable grease to by-pass the labyrinth seal formed by the rotating and static seal carriers 832a,b and 842a,b. This labyrinth seal is a tight labyrinth seal, and is formed substantially similar to the labyrinth seal 749a,b (FIG. 7A). A second set of passages 860 are defined by a gap between the radial outer surface of the static seal carriers 842a,b and the radial inner surfaces of the end plates 828a,b. This gap is a loose fit (as compared to the tight fit of the labyrinth seal), as it must allow clearance for both static and dynamic angular misalignment. The passage/gap 860 extends to the outer race/liner interface. The chamfered surfaces 831 of the liners 830a,b increase the size of the entrance to the passages 860 as compared to the entrance to the passages 760 (FIG. 7A). The passages 858 place the bearing chamber in communication with the exterior of the pillow block assembly. The passages 860 are sealed at their exits by the V-seals 852a,b. The inner portion of the V-seals 852a,b which seal the exits to the passages 860 is flexible. FIG. 9 shows an alternative configuration for the pillow block housing which utilizes a single external V-seal, but yet which still separates the lubricant for the bearing from the lubricant for the anti-friction liner/outer race interface. The pillow block assembly 900 includes a TDODA double-row tapered roller bearing assembly 912 identical to the bearing assembly 212 (FIG. 3A) through which the main shaft S passes. A pillow block housing assembly 924 radially surrounds the bearing assembly 912. The pillow block housing assembly 924 includes a body member 926 and upwind and downwind end plates 928 which are mounted to the body by threaded fasteners (not shown) arranged in a bolt circle. The body member 926 defines a bore having cylindrical surface 926a. The upwind end plate has a

first counterbore 928-1 at its radial inner end and a second counterbore 928- 2. The radial outer edge of the first counterbore 928-1 is approximately flush with the radial inner surface 926a of the body 926. Anti-friction liners 930 are received in the body bore. The anti-friction liners 930 are substantially similar to the liners 830a,b (FIG. 8). The upwind liner 930 extends beyond the axial outer edge of the body 926 and extends into the counterbore of the upwind end plate 928. Although the upwind liner 930 is shown to extend beyond the axial outer edge of the body 926 (as is also shown in FIG. 8), this is not necessary, and the axial outer end of the upwind liner can be flush with, or sent inwardly from, the axial end of the body 926.

Rotating seal carriers 932 are positioned on opposite sides of the inner race of the bearing assembly. An axial outer surface of the upwind seal carrier abuts a shoulder of the wind turbine shaft S. Rings 942 are secured to opposite sides or faces of the outer race of the bearing assembly 912 by means of fasteners 944. The ring 942 includes a channel 942a in its axial outer surface. A first labyrinth seal 948 is formed between the ring 942 and the rotating seal carrier 932. This first labyrinth seal is able to be a tight labyrinth seal as it handles only radial (or rotational) movement and does not need to consider angular movements of the ball/socket interface. The rotating (or dynamic) seal carrier 932 includes a channel 938 which receives V- shaped elastomeric seal 940.

The end plate 928 extends radially downwardly to cover or enclose the axial outer surface of the ring 942, and the ring 942 extends into the second counterbore 928-2 of the end plate 928. The end plate 928 includes a rib 928-3 which is aligned with and extends into the channel 942a of the ring 942. As seen, the end plate 928, the ring 942 and the rotating seal carrier 932 define a second labyrinth seal 950 which places the junction of the anti-friction liner and the outer surface of the outer ring of the bearing assembly in communication with the exterior of the pillow block assembly. This second labyrinth seal is a looser seal which provides a gap primarily for angular

motions, but also for radial and axial motion due to wear of the anti-friction liner. The first labyrinth seal 948 between the rotating seal carrier and the static seal carrier is generally aligned with, and in communication with, the second labyrinth seal 950. The V-seal 940, which rides in the channel 938 of the rotating seal carrier 932 seals against the axial outer surface of the end plate 928, and thus seals the exit from both the labyrinth seals 948 and 950. The rotating seal carrier 932 includes a passage 958 which is shown to be generally L-shaped. The passage 958 extends from an axial inner side of the seal carriers 932 to the channel 938. Thus, the exit to the passage 958 is sealed by the V-seal 940. In this embodiment, a single V-seal seals the exits of both labyrinth seals and the grease by pass. While not generally necessary, the embodiment of FIG. 9 (which separates the bearing chamber from the outer race/liner interface) does not provide a by-pass for the second labyrinth seal 950. FIG. 10 shows another alternative grease by-pass configuration. Like the embodiment of FIG. 9, the embodiment of FIG. 10 uses a single seal, however, it does not require fasteners in a bolt circle into the end face of the outer bearing race 1016.. Additionally, the embodiment of FIG. 10 provides for a grease by-pass for the outer race/liner interface in addition to the bearing chamber. In this embodiment, the pillow block housing 1000 includes a housing body 1026 defining a generally cylindrical bore which receives an anti-friction liner 1030. A bearing assembly 1012 (identical to the bearing assembly 212) is supported by the liner 1030. An end plate 1028 is secured to the axial end of the body 1026. As seen, the end plate 1028 abuts the axial outer end of the liner 1030. A slight gap may be provided at this juncture for the axial adjustment means, not shown.

A two-piece seal carrier 1032 abuts the axial ends of both the inner race 1014 and the outer race 1016 of the bearing assembly 1012. The seal carrier 1032 includes a radial inner section or shaft ring 1034 and a radial outer section or seal ring 1036. The seal carrier shaft ring 1034 includes a

ring 1034a through which the shaft S extends and which rests against the shoulder of the turbine shaft S and against which the bearing assembly inner race abuts. The seal carrier section 1034 also includes a flange 1034b which extends radially outwardly from the ring 1034a. A channel 1034c is formed in the radial outer surface of the flange 1034b which receives an O-ring or other functionally similar seal member 1038.

The seal carrier radial outer section or seal ring 1036 is generally in the shape of a ring which is fixed to the radial inner section 1034 by means of screws, bolts, or pins 1040 or similar fasteners. The pin 1040 can be threaded at its bottom to engage threads in the seal carrier radial inner section 1034. However, the pin upper section can be free of threads such that the pin upper section does not threadedly engage the seal carrier radial outer section 1036. A seal is formed between the radial inner and outer sections of the seal carrier 1032 by the O-ring 1038. The seal carrier radial outer section 1036 comprises an axial inner end 1036a proximate the end face of the bearing outer race 1016, an axial outer end 1036b, a radial outer surface 1036c and a radial inner surface 1036d. A small gap exists between the axial inner end 1036a of the seal carrier seal ring 1036 and the end face of the outer race1016. The radial outer surface 1036c extends axially from the axial inner surface to the axial outer surface, and hence extends from a position generally adjacent the bearing assembly outer race, under the radial inner surface of the end plate 1028 to overlie the flange 1034b of the carrier inner section 1034. As such, the carrier outer section 1036 has an external radial outer surface upon which a V-seal 1042 is received. As seen, the carrier outer section or seal ring 1036 defines a channel 1043 which receives the seal 1042.

A seen in FIG. 10, the radial inner surface of the end cover and the radial outer surface of the carrier outer section face each other and define a labyrinth seal 1046 between them which is shown to be comprised of facing, aligned grooves. This labyrinth seal is sized to handle both rotational and

angular motion. The seal 1042 seals against an axial outer face of the end plate 1028, and seals the exit to the labyrinth seal 1046. An inner flange 1036e extends from the axial inner surface 1036a under the bearing assembly outer race 1016, creating a close or tight fit axial and radial fit labyrinth seal 1047 to prevent easy passage between the socket interface lubricant and the roller bearing lubricant. The embodiment of FIG. 10 allows for the ring 1036 to be removed without the need to remove the end plates, as is required by the embodiment of FIG. 9.

The tight or close fit labyrinth seal 1047 is in communication with the looser labyrinth seal 1046 by means of the gap between the seal ring 1036 and the end face of the outer race. In view of this path of communication, it is possible that, under sufficient pressure, grease from the outer race/liner interface could enter the bearing chamber. However, this event is not terribly likely. Three independent lubricant bypass paths are provided in the seal carrier outer section 1036 to allow grease to by-pass the labyrinth seals. The paths are shown with their respective bores formed together in FIG. 10, and are shown separately in FIGS. 10A-C. The three passages comprise a selected combination of a main generally L-shaped passage 1050; a lower passage 1052; a third passage 1054; and a plug 1056. The main passage 1052 is generally L-shaped and extends axially outwardly from the axial inner surface of the 1036a of the seal ring 1036 and opens radially upwardly into the channel 1043 which receives the seal 1042. The axial inner end of the passage 1050 can be closed by the plug 1056. The lower passage 1052 extends radially upwardly from the radial lower surface 1036d of the seal ring 1036 and exits into the main passage 1050. As seen in FIGS. 10 and 10A, the lower passage is positioned to be proximate an axial outer end of the lubrication chamber. The third passage 1054 extends radially downward from the radial outer surface 1036c of the seal ring 1036 and also exits into the passage 1050. The second and third passages 1052 and 1054 are axially

offset from each other, with the third passage being positioned at a radial inner end of the first passage 1050 to be in communication with a radial inner end of the labyrinth seal 1046.

The first path comprises the main passage 1050 and the lower passage 1052, with the passage 1050 being blocked at its axial inner end by the plug 1056. This first path provides a passage communicating from the bearing chamber to the main passage exit in the seal receiving channel 1043. Grease passing through this first path follows the path shown by the arrow A1 in FIG. 1 OA. This first passage is a true grease by-pass and allows for grease in the bearing chamber to by-pass the tight labyrinth 1056 during regreasing, for example.

The second path comprises the main passage 1050 and the upper passage 1054, with the passage 1050 being blocked at its axial inner end by the plug 1056. An L-shaped bore 1056a is formed in the plug to allow for communication from the upper or third passage 1056 to the main passage 1050. This second path is shown by the arrow A2 if FIG. 1 OB and places the outer race/liner interface in communication with main passage exit below the V-ring seal in the seal receiving channel 1043. This path is less critical than the first path due to the fact that the labyrinth 1046 is a large (or loose) labyrinth through which grease may be able to pass during regreasing.

The third path is comprised only of the main passage 1050 without the plug 1056. This third path, shown by the arrow A3 in FIG. 1 OC, places the tight labyrinth seal 1047 and the labyrinth gap defined by the axial inner end 1036a and the end face of the outer race 1016 in communication with the exit below the V-ring seal in the seal receiving channel 1043. As noted above, the gap allows for communication between the bearing chamber and the outer race/liner interface. Although it is unlikely that grease or particulate matter would pass from the outer race/liner interface to the bearing chamber, this third path provides an escape for grease, under sufficient pressure, may be

urged to move between the two areas. Hence, this third path helps ensure separation of the outer race/liner interface and the bearing chamber.

The construction hole plugs 1056 are used to seal the first two paths from leakage through the inner face 1036a. The drawing of FIG. 10 illustrates all three passages in a single cross-section for illustrative purposes only. However, as can be appreciated, there may be a plurality of each of the three passages positioned about the circumference of the seal carrier outer section 1036, and depending on the path at a particular cross-section (i.e., radial position about the outer section 1036) will determine the passage configuration. Thus, while there may be several of the first paths (path A1 ) formed about the seal ring 1036, there may be only a few, or even none of the second and/or third paths (paths A2 and A3) Further, the seal ring can be provided with some second paths and no third paths, or some third paths and no second paths. FIGS. 1 1 -15A show other types of possible labyrinth seals and seal arrangements. FIG. 1 1 shows a four-seal design (two seals on each side) with a inner rotating seal carrier and an outer static seal carrier which is fixed to the end face of the outer race. A tight labyrinth is formed between the seal carriers, and the outer end of the labyrinth is sealed by means of a ring seal. A second seal seals the gap between the end plate and the static seal carrier. This second seal is secured at one end to an outer surface of the static seal carrier and at another end to an outer surface of the end plate.

FIG. 12 shows a seal configuration, substantially similar to the seal configuration of FIG. 7. That is, ring seals on each end, an inner ring seal on the rotating seal carrier to seal the tight labyrinth and a second ring seal on the static seal carrier to seal the gap between the static seal carrier and the end plate. FIG 12 shows how the V-seals flex due to axial movement of the radial outer or static seal carrier relative to the housing end plate.

FIGS.13 shows a variation in which the end plate becomes a seal carrier. This embodiment, like the embodiment of FIG. 10 utilizes a two-part

rotating seal carrier. However, the ring seal carried on the seal carrier seals against the end face of the outer race. The second seal is secured at a radial upper end between the end plate and the housing or liner, and includes a free end which extends radially inwardly and axially inwardly to seal against the end face of the outer race.

The embodiment of FIG. 14 uses a two-piece rotating seal carrier, as in FIGS. 10 and 13, but also includes a static seal carrier secured to the end face of the outer race. In this embodiment, the upper seal comprises a seal member secured in place between the static seal carrier and the end face of the outer race. In this instance, the second seal member extends radially upwardly to seal against a radial inner or bottom surface of the end plate. A comparison of FIGS. 14 and 14A shows flexing of the static seal in response to the angular movement of the static seal carrier and the housing and end covers. In FIG. 15, the static seal member is fixed to the end plate by a ring or extension which is secured to an axial outer surface of the end plate. The static seal member then seals against a ring secured to the axial outer end of the bearing assembly outer race. This seal ring would be analogous to a fixed seal carrier. However, rather than carrying the seal, the seal seals against this ring. The embodiment of FIG. 15 also includes a keeper ring on the ring secured to the outer race. This keeper ring (which is secured by means of fasteners, such as bolts to the seal ring) provides for access to the fasteners which secure the seal ring to the end face of the outer race, but prevents the fasteners from becoming loose in the assembly, thereby preventing the fasteners from falling into the bearing chamber (for example) during servicing of the pillow block assembly. FIGS. 15 and 15A also show seal travel due to the relative angular displacement but in this design the seal does not flex - it merely traverses the artificial extended ball surface built onto the static seal carrier whose center of rotation is the same as the spherical outer bearing race.

FIG. 16 shows an alternative upwind liner insert with a spring biased pre-load member M. As seen, the downwind liner insert extends over the center of the bearing assembly, and the upwind liner insert is shorter, such that the gap between the two liner sections is off-set from the axial center of the bearing assembly, similarly to the embodiment of FIG. 8.

The object of the design of the pillow block bearing assembly is to provide an assembly which allows for up-tower replacement of the anti-friction liners, separates the outer race/liner interface from the bearing chamber, and reduces the number of piece parts (to thereby reduce the cost of the overall pillow block bearing assembly). The various embodiments described above all meet these objectives to varying degrees, and some of the embodiments meet more of the objectives than others. For example, the embodiment of FIGS. 3B-4A allow for retrofitting of the liners and bearing assembly and up- tower replacement of the seals. However, these embodiments do not allow for up-tower servicing or replacement of the anti-friction liners or inspection or servicing (i.e., removal of dried grease) of the bearing assembly. Nor do these embodiments provide for separation of the outer race/liner interface from the bearing chamber.

The embodiments of FIGS. 5-6B provides for up-tower access (and hence servicing and replacement) of the anti-friction liners and inspection and servicing of the bearing assembly, in addition to up-tower replacement of the ring seals. The embodiments of FIGS. 6-6B have the added advantage of positively fixing the rotational position of the anti-friction liner segments relative to the housing. These embodiments, however, do not provide for separation of the outer race/liner interface from the bearing chamber.

FIGS. 7-8 provide for both up-tower servicing and/or replacement of the anti-friction liner and/or bearings as well as separation of the outer race/liner interface from the bearing chamber. In addition, these embodiments provide a grease by-pass to the tight labyrinth seal. The embodiments of FIGS. 7-8 however, use two-seals on each side, one for the

tight labyrinth that communicates with the bearing chamber and one for the looser labyrinth that communicates with the outer race/liner interface from the bearing chamber. To support both seals, these embodiments use two seal carriers (i.e., a rotating seal carrier and a static seal carrier) which increases the number of parts in the overall assembly.

The embodiments of FIGS. 9 and 10 provide for a single flexible seal. These embodiments both provide for up-tower replacement and servicing, separation of the outer race/liner interface from the bearing chamber, and grease by-pass. Both the embodiments include a similar number of piece parts. However, the embodiment of FIG. 10 does not require a bolt circle be formed in the end face of the outer race. Additionally, by providing at least a limited amount of up-tower access to the upwind and downwind bearing chambers, the bearing chambers can be inspected and dried and hardened grease can be removed from the bearing chamber. In view of the above, it will be seen that I have provided several embodiments of pillow block housings which include a bearing assembly which carries substantially only radial and axial loads, and thus has a substantially longer operating life than standard SRB bearings currently used in wind turbines. Additionally, maintenance on the pillow block housing can be performed "up tower". This eliminates the need for the wind turbine owner/operator to rent large cranes at great expense and take a turbine offline for an extended period of time while maintenance on the wind turbine is performed. Additionally, the pillow block housing allows for old and/or dried grease to be removed from the pillow block assembly. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. For example, any of the pillow block assemblies can be modified to accept to include any body/liner configuration. Thus, the flanged liner (which allows for the use of

segmented liner sections) can be used with any of the pillow block assemblies disclosed herein. Although the ring seals are shown as V-seals, other types of ring seals may work as well to seal the grease by-pass paths and labyrinth seals. Additionally, although the embodiments of FIGS. 1 1 -15 do not explicitly show grease by-passes, it will be apparent that these embodiments could be provided with a grease by-pass. These examples are merely illustrative.