PRIORITY DOCUMENTS

[0001] The present application claims priority from Australian Provisional Patent Application No.

2019904833 titled “VEHICLE AXLE AND DRUM BRAKE IMPROVEMENTS” and filed on 19 December 2019, the content of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to an axle assembly for a heavy vehicle.

BACKGROUND

[0003] Compressed air brake systems are generally used on heavy vehicles such as trucks, and particularly those having one or more trailers which must be linked into the brake system. Reasons for this include the fact that the air brake circuits on trailers can be easily and safely attached, and the supply of air is unlimited, so that systems can never run out of their operating fluid.

[0004] Drum brakes are commonly employed on trucks and trailers, because they are considered to be more durable than disc brakes, requiring fewer lining replacements in a given period. What is more, replacement parts for drams are typically cheaper due to a larger economy of scale.

[0005] Drum brakes in compressed air brake systems are generally of a cam follower type. That is to say, at least one end of each brake shoe comprises a cam follower (typically a roller) which follows a generally ‘S’ shaped cam, which depends from a shaft rotationally driven via an air-powered brake booster, which is located outside of the wheel.

[0006] Because the S-cam depends from the shaft, replacement of the S-cam involves sliding the shaft out of a supporting bush housing lengthwise. The length of this shaft is always longer than the clearance provided behind the wheel hub, so this cannot be done without removal of the wheel hub and bearings.

[0007] Similarly, replacing the anchor pins and bushes that retain the brake shoes involves knocking these out lengthwise with a hammer (as they are usually rusted in place), which again is almost impossible to achieve with the wheel hub in-situ.

[0008] Consequently, removal of the wheel hub is required to facilitate adequate access to perform these tasks, but disassembly and reassembly of the hub are both time consuming, and thus costly, and may void the warranty of parts such as wheel bearings, because modern wheel bearings are very reliable so long as they have correct tension and they are not disturbed. Moreover, in some cases the wheel bearings are pressed into the hub, so that these are not separable, meaning the hub must be discarded with the wheel bearing, and both of these replaced. This is an additional expense, especially when only an S-cam bush or brake shoes are in need of replacement.

[0009] It is against this background and the problems and difficulties associated therewith that the present invention has been developed.

[0010] Certain objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

SUMMARY

[0011] According to a first aspect, there is provided an axle assembly comprising an axle beam or housing and a brake mount depending from the axle beam or housing, the assembly further comprising a bearing housing comprising a body comprising a bearing comprising a through aperture for receiving a brake camshaft therethrough, the brake mount comprising a mount for the bearing housing, wherein the mount for the bearing housing and the bearing housing are cooperatively adapted for removable securement of the bearing housing with respect to the brake mount.

[0012] In one form, the axle assembly further comprises one or more fasteners for fastening the bearing housing with respect to the brake mount.

[0013] In one form, the one or more fasteners comprise one or more bolts.

[0014] In one form, the one or more fasteners comprise one or more nuts.

[0015] In one form, the one or more fasteners comprise one or more dowels.

[0016] In one form, the bearing is separable from the bearing housing. In this way, the bearing is replaceable.

[0017] In one fonn, in an alternative, the bearing is integral or unitary with the bearing housing. That is to say, the bearing coidd be fonned into the bearing housing.

[0018] In one form, the bearing comprises a bush.

[0019] In one fonn, the assembly further comprises a seal for the bush at each end thereof. [0020] In one form, the bearing housing further comprises a locking bracket comprising a base portion and a side portion, the base portion comprising a bolt hole for each bolt, and the side portion comprising a through aperture sized for receiving the brake camshaft therethrough but not the bearing therefor.

[0021] In one form, the base portion comprises an outwardly extending tag provided adjacent to each bolt hole, which in use, is bent up to register against a flat on the head of the bolt to prevent rotation of the bolt from loosening securement.

[0022] In one fonn, the brake mount comprises a first portion extending outwardly from the axle beam or housing on a first side thereof, this first portion comprising the mount for the bearing housing.

[0023] In one fonn, the brake mount comprises a second portion extending outwardly from the axle beam or housing on a second, opposing side thereof, this second portion comprising a pair of drum brake shoe mounts.

[0024] In one fonn, each of these shoe mounts comprises a collar comprising a through aperture.

[0025] In one fonn, two shoe mounts are positioned adjacent to each other with a centreline of the apertures therethrough extending parallel to each other.

[0026] In one fonn, a web bridges between the two collars.

[0027] In one fonn, a single straight slot extends transversely through the web and a wall of each of the collars at at least one point on the collar, so as to break through all of these, and divide each into inner and outer portions thereof.

[0028] In one fonn, a bolt hole extends through the web between the inner and outer portions and receives a (at least one) bolt which turns the inner and outer portions separated by the slot into a clamp, which can be tightened via the bolt to retain the brake shoe anchor pins, or loosened to release these for removal.

[0029] In one fonn, the assembly further comprises a locking tab comprising a base comprising an aperture for the bolt to pass through, and further comprising a tab, which in use, is bent up to register against a flat on the head of the bolt to prevent rotation of the bolt from loosening the clamp.

[0030] In one fonn, the slot breaks through the web and the wall of each of the collars at one point on each collar, so as to partially divide each into inner and outer portions thereof. [0031] In one form, the slot breaks through the web and the wall of each of the collars at two points on each collar, so as to completely divide each into inner and outer portions thereof.

[0032] According to a further aspect, there is provided an axle assembly comprising an axle beam or housing and a brake mount depending from the axle beam or housing, the brake mount comprising a pair of drum brake shoe mounts and at least one clamp mechanism for releasably retaining an anchor pin of each brake shoe

[0033] In one form, each of these shoe mounts comprises a collar comprising a through aperture.

[0034] In one form, each of these shoe mounts comprises a clamp mechanism for releasably retaining an anchor pin of each brake shoe.

[0035] According to a further aspect, there is provided a bearing housing comprising a body comprising a bearing comprising a through aperture for receiving a brake camshaft therethrough, a portion of the body being adapted for removable securement thereof with respect to a brake mount.

[0036] In one form, the bearing housing further comprises a mount for a brake booster, and a tubular housing for the brake camshaft extending between the body of the bearing housing and the mount for the brake booster.

[0037] According to a further aspect, there is provided a bearing housing comprising a body comprising a bearing comprising a through aperture for receiving a brake camshaft therethrough, a portion of the body being adapted for removable securement thereof with respect to a brake mount, the bearing housing further comprising a mount for a brake booster, and a tubular housing for the brake camshaft extending between the bearing housing and the mount for the brake booster.

[0038] According to a further aspect, there is provided a brake mount configured for securement with respect to an axle assembly comprising an axle beam or housing, the brake mount comprising a pair of drum brake shoe mounts, and a clamp mechanism for releasably retaining an anchor pin of each brake shoe in each of the mounts by releasably clamping each of the mounts about its respective anchor pin.

[0039] According to a further aspect, there is provided a brake mount configured for securement with respect to an axle assembly comprising an axle beam or housing, the brake mount comprising a first portion for extending outwardly on a first side thereof, and a second portion extending outwardly on a second, opposing side thereof, the first portion of the brake mount comprising a mount for a bearing housing comprising a body comprising a bearing comprising a through aperture for receiving a brake camshaft therethrough, wherein the mount for the bearing housing and the bearing housing are cooperatively adapted for removable securement of the bearing housing with respect to the brake mount, and the second portion of the brake mount comprises a pair of dram brake shoe mounts, and a clamp mechanism for releasably retaining an anchor pin of each brake shoe in each of the mounts by releasably clamping each of the mounts about its respective anchor pin.

[0040] For ease of description, an axle assembly embodying the present invention is described below in its usual assembled position as shown in the accompanying drawings and terms such as front, rear, upper, lower, horizontal, longitudinal, etc. may be used with reference to this usual position. However, the axle assembly may be manufactured, transported, sold, or used in orientations other than that described and shown here.

BRIEF DESCRIPTION OF DRAWINGS

[0041] Embodiments of the present disclosure will be discussed with reference to the accompanying drawings wherein:

[0042] Figure 1 is an isometric view of a non-driving (or trailer) axle assembly, with a portion of a brake drum removed to aid visibility of internals thereof, and viewed from the S-cam side;

[0043] Figure 2 is an isometric view of the axle assembly of Figure 1, with a portion of the drum of the drum brake removed to aid visibility of internals thereof, and viewed from an opposite side to the S-cam side;

[0044] Figure 3 is an exploded view of the assembly of Figure 2, viewed from an S-cam side thereof, with the drum removed to aid visibility of internals thereof;

[0045] Figure 4 is an exploded view of the assembly of Figure 3, viewed from an opposite side to the S- cam side;

[0046] Figure 5 is an isometric view of the axle from the assembly of Figure 1 , viewed from the S-cam side thereof, and minus brake shoes, S-cam and camshaft;

[0047] Figure 6 is a isometric view of the axle from the assembly of Figure 5, viewed from an opposite side to the S-cam side;

[0048] Figure 7 is a top view of a drive axle assembly;

[0049] Figure 8 is a top view of the drive axle assembly of Figure 7, with the dram of the drum brake removed to aid visibility of internals; [0050] Figure 9 is an underside view of the drive axle assembly of Figure 7;

[0051] Figure 10 is an underside view of the drive axle assembly of Figure 7, with the drum of the drum brake removed to aid visibility of internals;

[0052] Figure 11 is an exploded top view of the drive axle assembly of Figure 7;

[0053] Figure 12 is an exploded underside view of the drive axle assembly of Figure 7;

[0054] Figure 13 is an exploded isometric view of the drive axle assembly of Figure 7, viewed from the

S-cam side thereof;

[0055] Figure 14 is an exploded isometric view of the drive axle assembly of Figure 7, viewed from an opposite side to the S-cam side;

[0056] Figure 15 is an exploded isometric view of the drive axle assembly of Figure 7, viewed from the S-cam side thereof, with the hub and drum of the drum brake removed to aid visibility of internals; and

[0057] Figure 16 is an exploded isometric view of the drive axle assembly of Figure 7, viewed from an opposite side to the S-cam side, with the hub, drum and shoes of the drum brake removed to aid visibility of internals.

[0058] In the following description, like reference characters designate like or corresponding parts throughout the figures

DESCRIPTION OF EMBODIMENTS

[0059] Referring now to Figures 1 and 2, where there is illustrated one end of a non-driving (or trailer) axle assembly 1 comprising an axle beam 2 (also referred to as a housing) and a drum brake assembly 50 from a compressed air brake system.

[0060] Only one end of the axle assembly 1 is shown, as it should be understood that the other end comprises a mirror image thereof.

[0061] Where items are provided a reference number, but are not illustrated in Figures 1 through 6, it is because these items are illustrated in Figures 7 through 16.

[0062] Each end of the axle assembly 1 comprises a spindle 4 with machined surfaces on which there is rotatably mounted by bearings (not illustrated) a hub 60 comprising a plurality of studs 62 which will extend through holes 54 provided in a brake drum 52 (illustrated in Figure 1 ) and a wheel in turn so that the hub 60, drum 52 and wheel may be secured together by the application of wheel nuts to the studs 62.

[0063] With reference to Figures 3 and 4, it can be seen that each of the brake shoes 30 comprises a lining table 32 having a working face and a backing face, where a brake lining 34 depends from the working face, and a pair of parallel, spaced apart webs 36 depend from the backing face.

[0064] Each web 36 of a given brake shoe 30 comprises one of a pair of mutually aligned anchor pin holes 37, via which that brake shoe 30 is pivotally attached to one of a pair of brake shoe mounts 20.

Each web 36 of that brake shoe 30 further comprises, at an end distal to the anchor pin holes 37, one of a pair of mutually aligned cam follower mounts, for mounting opposite ends of a cam follower (or roller)

38 in the fonn of a roller retained therein.

[0065] Referring once more to Figure 1, the brake camshaft 40 extends from an air-powered brake booster 70 (not illustrated in Figures 1 through 6) into the drum brake 52, where it terminates at an S- shaped actuating cam (hereinafter S-cam) 42 which interposes the cam follower rollers 38.

[0066] In use, when the brake pedal of the vehicle is pushed, compressed air is supplied to the air- powered brake booster 70, which rotates the S-cam 42 via a push rod, a slack adjuster 72 and then the brake camshaft 40, driving the brake shoes 30 outward into contact with the brake drum 52.

[0067] Each outboard (when in use) web of each brake shoe 30 comprises a brake shoe guide 44. This guide 44 bears against the face of the S-cam 42 and works to prevent the brake shoe 30 from becoming misaligned, or ‘walking’.

[0068] Each web 36 of the brake shoe 30 comprises a spring attaclnnent aperture extending therethrough, and these are longitudinally coaxial.

[0069] The brake shoe 30 further comprises an access aperture 45 extending through the lining table and the brake lining. A centre line of the access aperture intersects a centre line of the attachment aperture. That is to say, the access aperture 45 extends in a direction toward the attachment aperture.

[0070] A return spring 46 bridges (i.e. extends between) the pair of brake shoes 30 inside of the drum 52, and performs the dual functions of returning the brake shoes 30 to their resting condition when the brake pedal is released, and maintaining the cam followers 38 in contact with the S-cam 42. A typical return spring 46 comprises a hook at each end thereof. [0071] When the brake shoes 30 are changed and/or the drum brake assembly 50 is serviced, the spring 46 must be removed in order to release the brake shoes 30. This involves overcoming the bias of the spring 46 so that the hook at each end of the spring 46 may be unhooked from a bolt 47 extending between the webs 36 of one of the brake shoes 30.

[0072] Referring now to Figures 3 through 6, a brake mount 6 depends from the axle beam 2, and comprises a first portion 6a extending outwardly from the axle beam 2 on a first side thereof, which comprises a mount 8 for a bearing housing 10. The brake mount 6 comprises a through aperture which receives an outboard end portion of the axle beam 2 therethrough, and it is then secured by bolts to an annular flange which is welded to the outboard end portion of the axle beam 2. Alternatively, the brake mount 6 could be welded directly to the axle beam 2.

[0073] The bearing housing 10 comprises a body 12 comprising a through hole 13 nesting a bearing 15 (a bush in this case) comprising a through aperture for receiving a brake camshaft 40 therethrough, and a seal for the bearing 15 at each end thereof. To this end, the brake mount 6 comprises a U-shaped recess located between a pair of outwardly extending arms 9, the recess providing clearance for the brake camshaft 40 to pass therethrough.

[0074] The body 12 of the bearing housing 10 surrounds the bearing/bush 15, and comprises a block of steel alloy of such a thickness as to substantially match the length of the bush 15, thereby nesting and supporting the bush 15. Such a bearing housing 10 is strong, rigid and robust. Preferably, the bearing housing 10 provides a reservoir of grease around the bush 15, for lubrication and wear reduction. The reservoir may be provided by way of a clearance for the grease provided between the bush 15 and the bearing housing 10, and/or the incorporation of a feature or features such as one or more annular grooves or channels.

[0075] The mount 6 for the bearing housing and the bearing housing 10 are cooperatively adapted for removable securement of the bearing housing 10 with respect to the brake mount 6. The mount 6 comprises a body having an outer face (i.e. facing the wheel) and an oppositely directed and parallel inner face. Similarly, the body 12 of the bearing housing 10 comprises an outer face (again facing the wheel and also the S-cam 42) and an oppositely directed and parallel inner face.

[0076] Each of the mount 6 for the hearing housing and the bearing housing 10 comprise machined mating surfaces which will abut when these parts are assembled. On the mount 6 this mating surface A is provided on the outer face thereof, and on the bearing housing 10 this mating surface B is provided on the inner surface thereof. [0077] Moreover, each of the mount 6 for the bearing housing and the bearing housing 10 comprise matching bolt holes 14a, 14b for receiving bolts 16 that will secure them together. On the mount 6, these bolt holes 14a are through holes extending between the inner and outer faces thereof. On the bearing housing 10, they are preferably also through bolt holes 14b, so that the bolts 16 pass through these and be secured by a nut.

[0078] In use then, each of the bolts 16 is passed through the mount 6 from the inner face thereof and the bearing housing 10 in turn, and secured by nuts.

[0079] Further still, each of the mount 6 for the bearing housing and the bearing housing 10 comprise matching dowel holes 18a and 18b for receiving dowels 19 that will bear any shear loads transferred between these assembled parts

[0080] The assembled mount 6 and bearing housing 10 provide a structure akin to what is referred to as ‘a spider’ on axles of the prior art.

[0081] A significant advantage of this arrangement is that the S-cam 42, brake camshaft 40 and the bush 15 can now be very easily replaced by removal of the bearing housing 10. The springs 46 can be removed via access aperture 45, so if the shoes 30 are still servicable, then the brake shoes 30 do not need to be removed in order to remove the bearing housing 10, instead they can be merely swung out of the way.

[0082] The hub 60 need not be removed to remove the bearing housing 20, S-cam 42, brake camshaft 40 and bush 15, and can remain in situ, so it is not necessary to disturb serviceable bearings. The bush 15 and seals nested in the bearing housing 10 are easy to replace without fear of damaging the bearing housing 10 by the commonly employed practice of knocking out an old bush and knocking in a new bush. One might have a serviced bearing housing 10 assembly ready with a replacement bush 15 already fitted to reduce downtime. Moreover, if the bush 15 is heavily worn, this can result in the brake camshaft 40 wearing on the bearing housing 10, but this bearing housing 10 is now easily replaced, and could even be mass-produced and treated as a disposable item.

[0083] The brake mount 6 further comprises a second portion 6b extending outwardly from the axle beam 2 on a second, opposing side thereof, this second portion 6b comprising a pair of dram brake shoe mounts 20. Each of these shoe mounts 20 comprises a collar comprising a through aperture 22 for receiving an anchor pin 39 on which a dram brake shoe 30 is mounted for pivotal movement, in an oppositely directed arrangement, for enclosure within and cooperation with a cylindrical internal surface of the rotatably mounted dram 52, to which the wheel assembly of the vehicle is attached. [0084] With reference to Figure 4 in particular, it can be seen that each anchor pin 39 is an assembly comprised of a tubular pin body 39a with a washer 39c at each end and a bolt 39b whose shank is passed through both the pin body 39a and the washers 39c and secured by a nut 39d. In use, the washers 39c aid retention of the pin body 39a in the shoe mounts 20 endwise, and so must be removed to change out the pin body 39a.

[0085] The two shoe mount collars 20 are positioned adjacent to each other with a centreline of the apertures 22 therethrough extending parallel to each other. A web 24 bridges between the two collars 20. A single straight slot 26 extends transversely through the web 24 and a wall of each of the collas 20 at one point on the collar, so as to break through all of these, and divide each into inner and outer portions thereof. A bolt hole 28 extends through the web 24 between the inner and outer portions, with the hole in the outer portion being a cleaance fit aound a bolt 29, and the hole in the inner portion being tlneaded to and receive the bolt 29, which forms the inner and outer portions separated by the slot 26 into a clamp mechanism, which can be tightened (via the bolt 29) to retain the brake shoe anchor pins 39 by closing the slot 26 and clamping each of the mount collars 20 about its respective anchor pin 39, or loosened to open the slot 26 and release the clamp for removal of the anchor pins 39 without need for a hanmer to knock them in or out. A locking tab 27 is keyed between the collas 20 and comprises a tab 27a which is bent up to register against a flat on the head of the bolt 29 and prevent the bolt from 29 from turning unintendedly and potentially loosening the clamp.

[0086] A significant advantage of this arrangement is that replacing anchor pins 39 is made quick and easy, and no longer necessitates bashing these in or out with a hanmer, thereby eliminating damage caused by this practice. There is also a reduced likelihood of the brake mount 6 being danaged by an anchor pin 39 wearing through into the brake shoe mounts 20. The likelihood of sideways movement in the brake shoe 30 is also significantly reduced because the anchor pin body 39a of the anchor pin 39 is now clanped in the brake shoe mount 20, further preventing unwanted movement, including cycling movement of the type which can cause elongation of holes 22.

[0087] Referring now to Figures 7 through 16, where there is illustrated a drive axle assembly la comprising a drum brake assembly 50 from a compressed air brake system. Those pa ts of the drive axle assembly 1a which are identical to those of non-drive axle assembly 1 of Figures 1 through 6, will be denoted by the sane reference numbers, and will not be described in detail again here.

[0088] Axle assembly la comprises an axle housing 2, and each end of the axle assembly la comprises a spindle 4 with machined surfaces on which there is rotatably mounted by bearings (not illustrated) a hub 60 comprising a plurality of studs 62 which will extend through holes 54 provided in a brake drum 52 (illustrated in Figure 1) and a wheel in turn so that the hub 60, drum 52 and wheel may be secured together by the application of wheel nuts to the studs 62. [0089] Each of the mount 6 for the bearing housing and the bearing housing 10 comprise machined mating surfaces which will abut when these parts are assembled. On the mount 6 this mating surface A is provided on a radially outwardly directed (i.e. away from the axle housing 2) face thereof, and on the bearing housing 10 this mating surface B is provided on a radially inwardly directed (i.e. toward the axle housing 2) face thereof.

[0090] A locking bracket 80 which serves multiple functions is provided. The locking bracket 80 comprises a plate body bent into an L-shape so as to comprise a base portion 82 and a side portion 84.

The base portion 82 comprises matching bolt holes 83 for receiving the bolts 16 therethrough, and an outwardly extending tag 86 provided adjacent to each bolt hole. The side portion 84 comprises a through aperture 85 for receiving the brake camshaft 40 therethrough, but not the bearing 15 therefor.

[0091] In use, the base portion 82 of the locking bracket 80 is seated atop of the bearing housing 20 with the side portion 84 extending down the side of the bearing housing 20 on the outer side thereof. The side portion 84 serves to aid with retention of the bush 15 and it seals, and to protect the seal from wear caused by the S-cam 42.

[0092] Once the bolts 16 have been tightened, each of the tabs 86 is bent to bear against a flat on the bolt 16 to which it is adjacent, and thereby prevent the bolt 16 from working loose in use.

[0093] In this embodiment, the bearing housing 10 further comprises a mount 74 for a brake booster 70, and a tubular housing 76 for the brake camshaft extending between the body 12 of the bearing housing 10 and the mount 74 for the brake booster 70. That is to say, these comprise a unitary assembly which is removable in one piece by loosening of the bolts 16. This facilitates fast removal for servicing, or exchange for either a new or a pre-serviced change over assembly, thereby minimising vehicle downtime.

[0094] The mount 74 for the brake booster 70 comprises a bracket to which the brake booster 70 is bolted.

[0095] The mount 74 for the brake booster 70 also comprises slotted bolt holes so that a slack adjuster 72 circlip can be removed and the bolts 16 securing the booster 70 can be loosened so that the booster 70 and the slack adjuster 72 can be slid on and off.

[0096] All bush and seal housings can now be made ready for a trailer or a truck before the vehicle is brought in for service, and any brake component can now be replaced without significant disassembly of other components, or removing the hub 60. [0097] Most operators of tracks and trailers equipped with axles of the prior art replace all parts on a wheel end even though only one or two components of the brake system (most commonly S-cam bushes and/or brake shoes 30) is worn out, so as to avoid the need for repetition of effort and additional downtime. Advantageously, the ease of servicing of tire axle according to the present invention permits replacement of only worn components, and only as required. Alternatively, the present invention permits exchange for either a new or a pre-serviced change over assembly, thereby minimising vehicle downtime.

[0098] Throughout the specification and the claims that follow, unless the context requires otherwise, the words “comprise” and “include” and variations such as “comprising” and “including” will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

[0099] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any fonn of suggestion that such prior art fonns part of the common general knowledge.

[00100] It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It w'ill be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.