MULTIPLE CAGE GRINDING DEVICE

Technical Field

A machine for regrinding multiple cages of a constant velocity universal joint workpiece.

Background Art

Machines for manufacturing or repairing one or more of the components of constant velocity universal joints are well known. These prior art machines are not adapted to readily and efficiently regrind the cages of constant velocity universal joints.

It is an object of this invention to provide a grinding machine which can accurately grind several ball cages of a universal joint mounted on a multiple cage holder.

It is another object of thiε invention to provide a grind¬ ing machine in which a fixed spindle contacts a multiplicity of movable workpieces.

Summary of the invention

In accordance with this invention, there is provided a machine for grinding a multiplicity of cages. The machine comprises an apparatus for preferably holding from 1 to 4 aligned cages and for moving the holding apparatus in the X axis, the Z axis, clockwise, and counterclockwise.

Brief description of the drawings

The present invention will be more fully understood by reference to the following detailed description thereof, when read in conjunction with the attached drawings, wherein like

-2-

reference numerals refer to like elements, and wherein:

FIG. 1 is a front view of one preferred grinding machine of the invention;

FIG. 2 is a side view of the grinding machine of FIG. 1; FIG. 3 is a front view of the base of the machine of FIG. i;

FIG. 4 is a side view of the base of FIG. 3;

FIG. 5 is a top view of the base of FIG. 3;

FIG. 6 is another side view of the base of FIG. 3;

FIG. 7 is an exploded view of the machine of FIG. 1;

FIG. 8 is a sectional view of a universal constant velocity joint;

FIG. 9 is an exploded, perspective view of the universal constant velocity joint of FIG. 8;

FIG. 10 is a front view of the machine of FIG. 1 shown with its multiple cage holding fixture in place;

FIG. 11 is a partial top view of the grinding machine of FIG. 1;

FIG. 12 is a side view of the grinding bit used in the grinding machine of FIG. 1;

FIG. 13 is a front view of the grinding bit of FIG. 12;

FIG. 14 is an enlarged sectional view of a portion of the grinding bit of FIG. 12;

FIG. 15 is a front view of a preferred alignment tool used in the system of the invention;

FIG. 16 is a top view of a preferred alignment tool depict¬ ed in FIG. 15;

FIG. 17 is a front view of one preferred multiple cage holder of this invention;

FIG. 17A is a front view of the shaft of the multiple cage holder of FIG. 17;

FIG. 17B is a front view of the shaft of FIG. 17A with a

first ball cage loaded onto it;

FIG. 17C is a front view of the shaft of FIG. 17B with a conical clamp;

FIG. 17D is a front view of the shaft of FIG 17C with a datum plate;

FIG. 17E is a front view of the shaft of FIG. 17D with a second ball cage;

FIG. 18 is a front view of another preferred multiple cage holder of this invention;

FIG. 19 is a perspective view of the grinding bit of FIG. 12;

FIGS. 20, 21, and 23 illustrates the cage of FIG. 19 with the grinding bit of FIG. 19 being disposed within it in vari¬ ous positions;

FIG. 24 is a front view of a portion of another preferred grinding machine of this invention;

FIG. 25 is a side view of the grinding machine of FIG. 24;

FIG. 26 is a sectional view of a portion of the machine of FIG 24;

FIG. 27 is a side view of the grinding bit assembly used in the machine of FIG. 24;

FIG. 28 is an exploded view of the grinding bit assembly of FIG. 24;

FIG. 29 is a partial perspective view of the machine of FIG. 24, illustrating a universal joint housing being ground;

FIG. 30 is front view of the machine of FIG. 29;

FIG. 31 is a schematic view illustrating the grinding of a universal joint housing;

FIG. 32 is a schematic view of the grinding assembly of FIG. 29;

FIG. 33 is a perspective view of a grinding wheel assembly;

FIG. 34 is a front view of a preferred grinding machine

utilizing the grinding wheel assembly of FIG. 33;

FIG. 35 is side view of the machine of FIG. 34;

FIG. 36 is a perspective view of another preferred grinding bit;

FIG. 37 is a front view of another preferred grinding ma¬ chine of this invention; and

FIG. 38 is a top view of a portion of the grinding machine of FIG. 37.

Description of the preferred embodiments

FIG. 1 is a front view of multiple cage grinding machine 10. Grinding machine 10 is comprised of base assembly 12, cover 14, oil mist removal unit 16, key pad/display unit 18, multiple cage holder 20, and grinding spindle 22.

The key pad.display unit 18 is preferably connected to an indexer (not shown) which is the control unit for the stepper motors 90, 92, and 106.

With the use of known ball cages of known dimensions dis¬ posed on a cage holding fixture in known or ascertainable positions, the control unit (not shown) is capable of determining the precise location of the window openings on such cages and where and how to grind them.

Panel 24 is removably attached to base 26 by conventional fastening means (not shown). Hingeably attached to panel 24 is door 28.

Referring again to FIG. 1, grinding machine 10 is comprised of a coolant fan inlet 29. Air is drawn through a filter (not shown) in fan inlet 29 by an fan (not shown), and the filtered air thus produced is used to cool the electrical assembly (not shown) disposed within cabinet 31.

A preferred base 26 which may be used in the grinding machine 10 is shown in more detail in FIGS. 3, 4, 5, and 6.

In these figures, one embodiment of a particularly stable base 26 is illustrated. In this embodiment, 26 is preferably constructed from a multiplicity of rectangular hollow steel tube members. Vertical members 30 preferably are 2"x2" steel tubing with a length of 24 inches, and vertical member 32 is 2"x4" steel tubing with a length of 24 inches. Each of verti¬ cal member 30 and 32 is supported by (and welded to) steel feet 34, which preferably are 2"x6" steel tubing with a height of 6 inches.

Disposed between, and welded to, steel feet 34 is lower longitudinal member 36, which is 2"x2" steel tubing.

The top section 38 of base 26 is comprised of longitudinal members 40 and 42, each of which is preferably constructed from 2"x4" steel tubing. The length of members 40 is prefer¬ ably about 52 inches, and the width of members 42 is prefer¬ ably about 24 inches. Angle irons 44 and 46 extend from one longitudinal member 40 to the other longitudinal member 40.

A panel 48 is preferably welded in place onto the top portion 38 of base 26.

The preferred baεe structure depicted in FIGS. 3-6 is substantially rigid and consequently, minimizes vibration during the grinding operation. The base 26 preferably has a natural frequency of at least 800 hertz.

The natural frequency of a structure is the frequency at which a body or system vibrates when unconstrained by external forces.

The load carrying capacity of base 26 is preferably at least about 400 pounds and, more preferably, is at least about 1,500 pounds.

The torsional stiffness of base 26 is preferably at least about 500 foot-pounds per radian.

Without wishing to be bound to any particular theory,

applicants believe that the unique properties of their base 26 substantially reduces the amount of "chatter" encountered during grinding. Chatter is the vibration of the grinding assembly caused by excitation at its natural frequency.

Referring again to FIG. 3, in one embodiment, not shown, a chiller (not shown) is disposed within compartment 50, which is formed by walls 52, 54, 56, and 58. This chiller (not shown) is preferably a liquid chiller which is operatively connected to spindle 22 (see FIG. 1) and preferably maintains the spindle at a temperature of less than about 80 degrees Fahrenheit.

In one embodiment, not shown, one or more of the chambers within hollow structural members 30, 32, 34, 36, 40, and 42 may be filled with vibration reducing material.

The vibration reducing material used may be, e.g., sand, concrete, and the like. In one embodiment, the vibration reducing material has a vibration loss coefficient of less than 0.01 This material may be, e.g., epoxy resin, sand, concrete, and the like.

Referring again to FIG. 1, grinding machine 10 is prefer¬ ably comprised of oil mist removal unit 16. The function of oil mist removal unit is to remove oil mist created during high-speed grinding process; and it preferably can remove at least about 95% of the oil mist in an air sample flowing through it at a rate of at least 250 cubic feet per minute.

One may use any of the oil mist removal devices known to those skilled in the art as an oil mist removal unit 16. Thus, one may use a "Filtermist" device which is sold by Royal Products (of 210 Oser Avenue, Hauppauge, N.Y.) as model number 275CFM (catalog number 28035)

Removable cover 14 iε comprised of an opening 60 within which is dispoεed a sliding glass door assembly 62. In the

embodiment depicted, cover 14 is not mechanically attached to sliding glass door assembly 62 and, thus, can be readily removed from the base 24. Because cover 14 is preferably attached to base 12 by conventional fasteners (such as screws), it can readily be detached from base 12 to obtain more ready access to the innards of the machine 10.

FIG. 2 is side view of the grinding machine 10 of FIG.l with the exterior panels (such as panel 24) removed to better illustrate the structure of the device 10.

Cover 14 sits upon base members 40 and 42 and is attached to such abase members 40 and 42 by conventional fasteners, such as screws (not shown). Upon removal of these fasteners, cover 14 can readily be removed to furnish access to the grinding cabinet 64 of machine 10 (see FIG. 7).

In one embodiment, grinding cabinet 64 is formed by sheet metal panels 66 welded together. The sliding glass door assembly 62 may be attached to the grinding cabinet 64 by conventional means such as screws, silicone sealant, etc.

Oil mist removal unit 16 is connected to grinding cabinet 64 by means of flexible seal 68. Air flows in the direction of arrows 72 and 74 around baffle 70 and thence through ori¬ fice 76 into air mist removal unit 16.

Grinding cabinet 64 is attached to base plate 78 by conven¬ tional means, such as screws, bolts, silicone εealant, etc.

Rotary table 80 is mounted on bracket 82 which, it turn, is mounted on X,Z slide 84.

One may use any conventional means for moving bracket 82 in the X and Z axes. Thus, referring to FIG. 10, slide 84 is comprised of stepper motors 90 and 92. Stepper motor 90 moves bracket 82 in the direction of arrows 94 and 96 by means of a ball screw (not shown) on slide 98. Stepper motor 92 moves bracket 82 in the direction of arrows 100 and 102 by means of

a ball screw (not shown) on slide 104.

Rotary table assembly 80 is comprised of a stepper motor (not shown) which is operatively connected to bracket 82 and rotates it in either a clockwise or counterclockwise direc¬ tion.

Slide assembly 84 is also illustrated in FIG. 14.

Referring to FIG 2, it will be seen that machine 10 is comprised of coolant delivery system 88 which is comprised of a pump (not shown), oil inlet line 114, oil return line 108, and oil catch basin 110. Oil caught in catch basin 110 is returned to coolant delivery system 88, and returned via a pump (not shown) via oil delivery line 114 to machine 10.

The oil mist captured in oil mist separator unit 16 is separated from air and other fluid in separator 16 by conven¬ tional means such as centrifugation.

The oil mist thus separated is then returned to the coolant delivery system tank 88 via oil mist return line 112.

Referring to FIG. 7, cover 14, grinding cabinet 64, and sliding glasε door assembly 62 can be readily removed from base plate 78 by removing any fastenerε and/or εeals securing said units (not shown) and lifting the unit in the direction of arrows 116.

A fluorescent light fixture 118 is preferably disposed within grinding cabinet 64.

FIG. 8 is a sectional view of a typical constant velocity universal joint 120 which is comprised of outer race spline 122, outer race body 124, cut off axle shaft 126, inner race splines 128, inner race 130, cage 132, and bearing balls 134. Fig. 9 is an exploded view of some of these components.

Referring again to FIG. 10, εpindle 22 iε preferably fixed in place by meanε of itε attachment to pedestal 136 by means of spindle mount 138.

Pedeεtal 136 is preferably attached to base plate 78 by conventional fastenerε, such as screws, bolts, etc. In one preferred embodiment, pedestal 136 and spindle mount 138 consist essentially of aluminum. Applicants believe that the use of aluminum for these elements minimizes differences in coefficients of thermal expansion between the spindle mount 138, the pedestal 136, and the slide asεembly 84 (which also is preferably made from aluminum) .

In one embodiment, not shown, spindle pedestal 136 is preferably a hollow structure. In another embodiment, not shown, spindle pedestal 136 is filled with a vibration reduc¬ ing material such as, e.g., sand or concrete.

Spindle mount 138 preferably is attached to spindle pedes¬ tal 136 by conventional means.

Spindle 22 is preferably adapted to rotate at a speed 77 of at least about 30,000 revolutionε per minute and, more prefer¬ ably at a εpeed of from about 30,000 to about 50,000 revolu¬ tionε per minute.

The εpindle 22 rotateε grinding bit 140, which rotateε while being maintained in substantially the same vertical and horizontal position. The grinding bit 140 contacts cages 132 (shown in dotted line form in FIG. 10) when they are moved into the appropriate positionε viε-a-viε grinding bit 140. Cageε 132 are preferably mounted in a multiple cage holding device (see element 160 or element 161 of FIG. 17 or FIG 18); and the multiple cage holding device is preferably moved so that the grinding bit 140 is dispoεed in the appropriate positions within the windows of cages 132.

Referring to FIG. 19, the ball cageε in conεtant velocity universal joints generally contain six windows 212, each of which are substantially congruent with each other. The term congruent, as used in this specification, meanε that the

windowε have substantially the same size and shape. Thus referring again to FIG. 19, each of congruent windows 212 has a subεtantially rectangular εhape with parallel linear walls 215. The cage windows 212 may, but need not, contain arcuate corner portions 217.

The cage windows 212 must be disposed vis-a-viε grinding bit 140 so that the grinding bit 140 is capable of grinding the appropriate surfaces of each of the windows. In the process of this invention, this is accomplished by dispoεing a multiplicity of cageε in fixed, stacked relationship to each other and to specified reference points so that the congruent windows on one stacked cage are vertically aligned with the congruent windows on a vertically adjacent stacked cage, and so that the distance of any congruent cages in any particular stacked cage can readily be determined by reference to speci¬ fied reference points.

In a preferred procesε of this invention, at least two cages are mounted upon a cage holding fixture 160 or 161. These cageε generally have the same size and shape, and the windows in each of the cages are substantially congruent with each other.

The process of this invention is designed to align the congruent windows of one cage with the congruent windows of another cage. Furthermore, because the height 141 of differ¬ ent ball cages 132 varies (see FIG. 21), the process of this invention is adapted to mount the cages on a holder at speci¬ fied reference points to compensate for such variances in height. The distance between any stacked cage 132 in cage holder 160 and the center of any of the windows in such cage can readily be determined by the process of this invention even if variations in the heights of vertically adjacent stacked cages 132 exist.

FIG. 11 iε a top view of the machine of FIG 10, in which meanε for attaching a multiple cage holder of thiε invention to the machine are illustrated.

FIG. 12 is a side view of a preferred grinding bit 140. Grinding bit 140 is a substantially integral structure which consists of a base 142 of high tensile steel and a tip 144 which is plated with an abrasive such as cubic boron nitride.

It is preferred that base 142 consist essentially of high tensile strength alloy steel with a tensile strength of from about 60,000 to about 150,000 pounds per square inch, a yield strength from about 40,000 to about 120,000 pounds per square inch, and a hardness (Rockwell C) of from about 20 to about 40.

Grinding bit 140 preferably has a length 146 of at least about 2.75 inches and more preferably, from about 2.75 to about 5.0 inches. The grinding bit 140 preferably has a diameter 148 of from about 0.25 to about 1.0 inches and more preferably, from about 0.3 to about 0.6 inches.

In one embodiment, grinding bit 140 iε comprised of a mark 150, which often iε left by a machining center.

Referring again to FIG. 12, grinding bit 140 iε comprised of an unplated section 152 and a plated section 144. The length 156 of the plated section 144 is preferably from about 0.25 to about 1.5 inches and also preferably is at least about 40 percent of the length 158 of the unplated section 152.

It iε preferred that the coating on plated section 144 consist essentially of cubic boron nitride. In one embodi¬ ment, a single crystal layer of cubic boron nitride is elec¬ troplated onto said steel subεtrate. In another embodiment, a single crystal layer of cubic boron nitride is brazed onto the steel εubεtrate.

FIG. 15 is a front view of one preferred embodiment of an

align ent tool adapted to align cages 132 dispoεed within cage holder fixture 160.

In one embodiment, multiple cage holder fixture 160 is adapted to hold four cages 132. In the embodiment depicted in FIGS. 18, multiple cage holder fixture 161 is adapted to hold three cages 132. Cage holder fixture 160/161 may be utilized with as few as one cage and as many as about six cages. It is preferred that from about 2 to about 4 cages 132 cages be used with cage fixture 160 or cage fixture 161.

Multiple cage holding fixtures 160 and 161 are each prefer¬ ably comprised of a shaft 162 comprised of threaded portions of 164 on itε exterior εurface. Fixedly mounted on shaft 162 are datum plates 166, 166' and 166".

The distance between base 172 and datum plate 166 is a fixed, known quantity, as is the distance between datum plate 166 and datum plate 166', and as is the distance between datum plate 166' and 166"; in one aspect of this embodiment, each of these distances is equal. Because the grinding machine knows what these distanceε are, regardless of height of the cage 132 mounted on the fixture 160, it also knows that a specified distance from either base 172, or datum plate 166, or datum plate 166', it will find a window on the stacked cage.

Referring to FIG. 18, also mounted on shaft 162 are clamp¬ ing cones 168 which, preferably, have a substantially conical shape. Each of such movable clampε 168 preferably contain internal threadε 170 which are adapted to mate with external threads 164 on shaft 162 at specified portions of said shaft. As the clamp is rotated in a clockwise or counterclockwise manner, its position vis-a-vis the nearest datum plate 166 will vary.

Figure 17A is a front view of a preferred embodiment of shaft 162 which differs in structure from the shaft 162 de

picted in FIGS 15, 17,and 18. Shaft 162 is preferably an integral structure preferably made of hardened steel. Shaft 162 preferably has a substantially conical shape and increases in diameter from its top 163 to its bottom 165.

Dispoεed along the length of shaft 162 are several annual ledges 167, 169, and 171 which are used to support datum plates 166. Since the distance of these annual ledges 167, 169, and 171 from base 175 is known, the diεtance from base 175 of datum plates of known thickness also is known.

Shaft 162 is also comprised of base 175, which is used to support the first cage 132 loaded onto the shaft (see FIG 17B) .

Top 163 of shaft 162 is compriεed of external threadε 173. External threadε 173 are alεo diεpoεed beneath each of ledges 167, 169, and 171.

Shaft 162 also is comprised of a base 175 comprised of recesses 177 and 179. Recesses 177 and 179 are adapted to engage with, and be disengaged from, spring-loaded plungers discussed later in this specification (see, e.g., FIG 11).

Referring to FIG 17B, and in the first step of the process of this invention, cage 132 is positioned until it is contigu¬ ous with base 175. Thereafter, as is illustrated in FIG 17C, clamping cone 168 is disposed on shaft 162 until its internal threads 181 and 183 are contiguous with external threads 173 of shaft 162. Rotation of clamping cone 168 in a clockwise direction moves it downwardly in the direction of arrow 185 and thus presεes against, centers, and secures cage 132.

In the next step of the process, illustrated in FIG 17E, cage 132' is now disposed on shaft 162 until it iε contiguous with datum plate 166. Because the system knows the location of the ledges 167, 169 and 171 as well as the location of the datum plates 166, it alεo knows the distance between the

centers of windows 212' and 212" of adjacent cageε. With this knowledge of the distance between centers of the windows in all other stacked adjacent cages, it can move the cage holding mixture 160 or 161 with precision to grind such stacked wind¬ ows accurately in spite of posεible variations in the height of such cages 132.

The fixtures 160 and 161 are preferably configured by first sliding the first cage to be mounted down the shaft until it impacts base 172. Because the clamps are configured so that they get bigger from top to bottom, the first cage can readily be pushed towards baεe 172.

Once the first cage has been disposed between base 172 and the next adjacent clamp 168, the fixture 160 and/or 161 may be mounted on alignment tool 158. Section 174 of shaft 162 is preferably disposed with orifice 176 of base 178 of alignment tool 158 while finger 180 is in raised poεition 182.

In one embodiment, the cage fixture 160 or 161 containing one or more cageε diεposed on it has its portion 174 of shaft 162 disposed within orifice 176. Thereafter cage fixture 160 or 161 is rotated in a counterclockwise direction from about 15 to about 45 degrees until spring loaded alignment fingers 191 and 193 (see FIG. 16) mate with recesses (not shown) in the base of fixture 160 or 161, thereby locking said fixture into place; a similar structure is illustrated in FIG. 11.

Once the radial alignment of the windows of a particular cage has been effected by the manner described, the multiple cage holding fixture 160 or 161 can be unlocked by pressing down on it while rotating it counterclockwise. Thereafter, when the fixture 160 or 161 has been fully loaded, it may be removably attached to the rotary table 80 (see FIG. 11).

Referring again to FIGS. 15-18, the cage is rotated to allow alignment finger 180 to become disposed within a cage

window, thereby aligning it such window; and the cage is then tightened in place by rotating the adjacent movable clamp 168 clockwise to lock the first cage into place. Thereafter, alignment finger 180 is then raised, the multiple cage holding fixture 160 or 161 is then removed from the alignment tool 158, a second cage 132' is then dispoεed on top of the next adjacent datum plate 166', the assembly is then mounted again in alignment tool 158, the finger 184 is then disposed within the window of cage 132' to align it, the adjacent movable clamp 168' is then turned clockwise to fix the cage in place, and the procesε is then repeated for the third cage 132".

Because fingers 180, 184, 186, and 188 are vertically aligned with each other, the cages 132, 132', 132" and 132'" aligned with alignment tool 158 will each have their cage windows vertically aligned.

FIG. 16 is a top view of alignment device 158. Base 178 of this device contains orifices 190, 192, 194, and 196 which can be used, together with conventional fasteners, to fixedly attach alignment tool 158 to any work table.

Device 158 preferably is comprised of at least one thumb screw 198 which allows one to removably attach each alignment body 200 on specified positionε on arm 202 which correεpond to the heightε of the cageε 132 on cage apparatuε 160 or 161.

Arm 202 iε swingably attached to base 178 by meanε of pivot pin 402 thereby allowing the fingerε 180, 184, 186, and 188 to be moved away from or towardε the windowε on the cageε 132 mounted on fixture 160 or 162.

It iε preferred to attach fingers 180, 184, 186, and 188 to bodies 200 by means of a bolt 206 and nut 298, although other faεtenerε may also be used. It is preferred that each of such fingers 180, 184, 186, and 188-188 be spring loaded.

The use of applicant's device allows one not only to align

the adjacent cageε 132 so that the distances between the centers of their windowε are known, but is also allowε one to align εuch windowε with each other in vertical orientation.

The cage holding fixture 160 and/or 161 with the cageε aligned in it may be attached to (or detached from) the rotary table 80 (see FIG. 11) in substantially the same manner as it is attached to (or detached from) alignment tool 158. Thus, referring to FIG 11, the loaded cage holding fixture 160 or 161 containing one or more cages disposed on it has its por¬ tion 174 of shaft 162 (see FIGS. 17 and 18) disposed within orifice 199. Thereafter cage fixture 160 or 161 is rotated clockwise from about 15 to about 45 degrees until spring loaded alignment fingers 201 and 203 mate with recesses 177 and 179 in the base of 175 fixture 160 or 161 (see FIGS. 17A to 17F), thereby locking said fixture into place. To disen¬ gage the cage holding fixture 160 or 161 from the rotary table 80, it may be turned counterclockwise to disengage spring loaded fingers 201 and 203.

FIG. 19 illustrates grinding bit 140 disposed within a window 212; in this embodiment, the center of each window 212 iε preferably located about 60 degreeε away from the center of each adjacent window; and the windows 212 are substantially symmetrically disposed around the perimeter of cage 132.

The grinding bit 140 rotates, but it is fixed in the X, Y, and Z axis. The cage may be moved in the direction of arrows 214, 216, 218, 220, 222, and/or 224 to change the position of the cage and its window 212 vis-a-viε grinding bit 140.

The relative position of tool bit 140 can be changed in the left or right direction by rotating cage 132 which, in turn, is effected by rotating the cage fixture 160/161 attached to rotary table 80 a specified number of degrees, depending on the length of the cage windows 212 and 212' . By comparison.

the relative position of tool bit 140 may be changed in the up or down position by moving in the cage fixture 160/161 in the Z axis of the XZ slide 84. When it iε deεired to remove the grinding bit 140 from window 212, thiε may be effected by moving the XZ slide 84 in the X axis.

By way of illustration, when grinding bit 140 is in the poεition depicted in FIG 20, the multiple cage fixture 160 or 161 (not εhown) in which the cage is mounted may be moved in the direction of arrow 220 until the grinding bit is in the position depicted in FIG 21.

By way of further illustration, when the grinding bit 140 is in the position depicted in FIG 21, the multiple cage holder 160 or 161 (not shown) on which the cage 132 is mounted can be moved in the direction of arrow 224 to remove the grinding bit 140 from window 212, the multiple cage holder 160 or 161 (not shown) can then be rotated counterclockwise the appropriate number of degrees in the direction of arrow 216, and the grinding bit 140 can be inserted into window 212' to assume the position depicted in FIG. 22 by moving the multiple cage holder 160 or 161 (not shown) in the direction of arrow 222.

By way of yet further illustration, when the grinding bit is in the position depicted in FIG. 22, it may be moved to the position depicted in FIG 23 by moving the multiple cage holder 160 or 161 (not εhown) in the direction of arrow 216.

FIG. 24 iε front view of a grinding machine 89 utilizing εubεtantially all of the elements of the grinding machine depicted in FIGS 1-23 but with these components arranged in a different configuration. In the machine 89 of FIG. 24, the rotary ^" table 80 is mounted vertically to the XZ slide 84 rather than horizontally, and a different grinding tip 226 is used.

FIG. 25 is a side view of the grinding machine 89 of FIG. 24.

FIG. 26 is a partial top view of FIG. 24, illustrating tool tip 226 grinding one track of housing 124. Referring to FIG. 26, it will be seen that housing 124 is attached to rotary table 80.

FIGS. 27 and 28 illustrate a grinding bit which can be used to grind the housing 124 (not shown). This grinding bit is compriεed of an arbor 228 which, preferably, consists essen¬ tially of carbide material. The grinding bit is also com¬ prised of grinding tip 226 which is coated with cubic boron nitride material 232.

Referring to FIGS. 27 and 28, it is preferred that the front of the grinding plated portion 232 of grinding tip 226 be subεtantially εpherical.

Figure 29 illuεtrates how plated portion 232 of the grind¬ ing tip is disposed vis-a-vis the tracks 230 of housing 124. As will be apparent to those skilled in the art, the rotary table 80 (not shown) which holds such housing 124 may be moved in the X axis and/or the Z axis to separate the housing 124 from the tool bit 228. Thereafter, the houεing 124 may be rotated by the rotary table 90 in the direction of arrow 232 or 234, and the housing 124 may then be moved in the X axiε and/or the Z axiε to reposition the tool bit 128 in another track 230.

FIG. 32 shows that housing 124 can be made to move in a substantially arcuate path (see arrows 236 and 238) by simul¬ taneously coordinating motion in the X and Y axis. Many other motions can be created by such simultaneous coordination. Thus, tool bit 226 attached to arbor 22 can be caused to grind a substantially accurately shaped track 230 in housing 124.

FIG. 33 shows an inner race 130 of a constant velocity

univerεal joint (not shown) being ground by a grinding wheel assembly 240.

FIG. 34 is a front view of an grinding machine 91 utilizing the grinding assembly of FIG. 33. FIG. 35 is a side view of the grinding machine 91 of FIG. 34 in which a sliding glasε door aεsembly 62 has been omitted for the purposeε of illus¬ tration. Referring to FIG. 35, a YZ slide 242 is used in place of the XZ slide 84 in the embodiment depicted.

FIG. 36 is a perspective view of grinding bit comprised of grinding tip 226 attached to arbor 228. In the embodiment depicted, the grinding bit is grinding inner race 130.

FIG. 37 is a perspective view of a grinding machine 250 comprising a grinding apparatus 252.

FIG. 38 illustrates a preferred embodiment of grinding apparatus 252 which is compriεed of YZ slide 242, εpindle 22, tool bit 226, arbor 228, houεing 124, rotary table 80, εtepper motor 92, ball slide 98, base plate 78, bracket 82, εpindle bracket 138.

It iε to be understood that the aforementioned description is illustrative only ant that changes can be made in the sequence of combinations and process steps, as well as in other aspects of the invention discussed herein, without departing from the scope of the invention as defined in the following claims.