WO1998016419A1

WO1998016419A1 - Load sharing wheel assembly for track laying vehicle

Info

Publication number: WO1998016419A1
Application number: PCT/AU1997/000686
Authority: WO
Inventors: James Arthur Nagorcka
Original assignee: Warane Pty. Ltd. Trading As Waltanna Tractors
Priority date: 1996-10-16
Filing date: 1997-10-14
Publication date: 1998-04-23
Also published as: GB9908453D0; DE19782050T1; GB2333273A; AUPO302096A0

Abstract

A load sharing wheel assembly which is suitable for use with a track for a track laying vehicle. The wheel assembly includes at least one wheel set (100), the wheel set (100) having two wheels (101, 102) which are spaced apart from one another so as to form a passage therebetween. Each wheel (101, 102) has a rim section (112) and is rotatable about an axis of rotation (z, z). The rim section (112) includes a primary load bearing portion (113) and primary guide portion (114), the surface of each portion (113, 114) being generally disposed in respective planes which are inclined to one another and the rotation axis (z, z) of each wheel (101, 102) being inclined to the planes of the portions (113, 114).

Description

LOAD SHARING WHEEL ASSEMBLY FOR TRACK LAYING VEHICLE

This invention relates generally to track laying vehicles and more particularly to a load sharing wheel assembly for use in such vehicles.

Track laying vehicles to which the invention can apply may comprise a vehicle body having a longitudinal axis extending between forward and rearward ends thereof and a pair of track assemblies disposed on opposite sides of the vehicle body. Each track assembly may comprise first and second wheels which are spaced apart in the direction of the longitudinal axis with at least one of the wheels defining a drive wheel. The assembly may further include a track which may for example be formed of elastomeric material the track being entrained around the first and second wheels and having a ground engaging surface, and an opposite wheel engaging surface with a plurality of power transmitting elements or drive lugs projecting from the wheel engaging surface. The vehicle may further include a plurality of load sharing wheels between the drive wheel and the idler wheel. An example of one such vehicle and track assembly therefor is described in applicant's International Application No. PCT/AU90/00542. The vehicle described in the above mentioned application is of the type commonly referred to as a positive drive track laying vehicle. It will be appreciated however that the load sharing wheel assembly could be used in some cases with other types of vehicle such as friction drive track laying vehicles.

The load sharing wheels currently in use comprise a series of wheel sets disposed in spaced apart relation between the first and second wheels. Each wheel set comprises a pair of spaced apart wheels the space between the wheels forming a passage through which the drive lugs on the track pass. The load sharing wheels are operatively connected to the vehicle frame and provide for a load supporting function as well as track belt guiding function. Currently known load sharing wheels have horizontal axes of rotation and as such frictionally bear on the sides of the lugs as a result of a sliding action between the side of the wheel and the lug as the lugs pass between the wheels of each set. If high side loads are applied to the vehicle such as if the vehicle is on a sloping surface the relative sliding movement can cause very high wear on both the wheel and the lug of the track.

It is an object of the present invention to provide an arrangement which alleviates the aforementioned problem.

According to the present invention there is provided a load sharing wheel assembly which is suitable for use with a track for a track laying vehicle, the wheel assembly including at least one wheel set, the wheel set including two wheels which are spaced apart from one another so as to form a passage therebetween, each wheel having a rim section and being rotatable about an axis of rotation. The rim section includes a primary load bearing portion and primary guide portion, the surface of each portion being generally disposed in respective planes which are inclined to one another and the rotation axis of each wheel being inclined to the planes of said portions.

The load sharing wheel assembly of the present invention is suitable for use with a track assembly which includes a track with a base part having a ground engaging surface and a wheel engaging surface and a series of drive lugs spaced apart from one another along the length of the track and projecting from the wheel engaging surface. The drive lugs may have lateral sides with wheel bearing surfaces thereon.

The arrangement is such that when the belt moves past the load sharing wheel assembly there is a component of rolling movement between the guide portion of each wheel and the wheel bearing surfaces of the drive lugs as well as between the load bearing portion of each wheel and the wheel engaging surface of the track.

Preferably, the rim section of each wheel is generally vee-shaped in cross-section one face defining the primary load bearing portion and the other face defining the primary guide portion. In operation the rotation plane of each wheel is inclined with respect to the plane of the wheel engaging surface of the track so that the apex of the vee-shape is disposed adjacent the junction of the track wheel engaging surface and lug wheel bearing surface. There may further be provided an axle assembly including a body portion operatively connected to the vehicle body and a pair of stub axles each being adapted to receive one of said wheels thereon, the stub axles being inclined downwardly and outwardly with respect to one another and with respect to the normal orientation of the vehicle. In one preferred form the axle assembly includes an intermediate or central section operatively connected to the vehicle body which the stub axle sections extending away from the intermediate section, the longitudinal axes of the stub axles being inclined to the longitudinal axis of the intermediate section. It will be appreciated that the stub axles could be independent parts.

Preferably, rim section of each wheel includes an elastomer ic covering thereon. The elastomeric material can be of any suitable form.

Preferably, each wheel is inclined at an angle which bi-sects the angle between the guide plane and the load bearing plane.

Preferably, the assembly includes a plurality of wheel sets at least one of said wheel sets being in the form of wheel set according to the invention as described above.

Preferred embodiments of the invention will be hereinafter be described with reference to the accompanying drawings and in those drawings :

Figure 1 is a side elevation of a typical track laying vehicle;

Figure 2 is a plan view taken along line A-A of Figure 1 ; and

Figure 3 is a schematic view showing a load sharing wheel set according to the present invention.

Figure 1 illustrates a track laying vehicle 1 of the type to which the load sharing wheel set of the invention is applicable. The vehicle 1 includes a chassis and frame 3 with a longitudinal axis 33, an operators cabin 4 and an engine 2. Connected to frame 3 is a drawbar 17 which is used to attach draft loads. The vehicle is propelled by an elastomeric track 9 along each longitudinal side of chassis 3 which is entrained around a drive wheel 5, an idler wheel 32 and load sharing track wheels 19, 20. Ground engagement of the track 9 is made by ribs 10 being part of track 9.

In the embodiment shown each track 9 has direct or positive drive engagement with the drive wheel 5 by means of engagement between the cross members 7 of the drive wheel

5 and the drive lugs 11 which are part of the track 9. Engagement between cross members 7 and drive lugs 11 is maintained by the hydraulic cylinder 31 tensioning the idler wheel 32 away from the drive wheel 5.

The track 9 and drive lugs 11 maintain lateral registry with the load sharing wheels

19 and 20 because these wheels form a channel or passage in a longitudinal line between the drive wheel 5 and idler wheel 32. As with the drive wheel 5 and idler wheel 32, lateral movement of the track 9 is restricted to lateral movement of the drive lugs 11 within the guiding surfaces of each pair of load sharing wheels 19 and 20.

Referring to Figure 3 there is shown a load sharing wheel set according to a preferred embodiment and generally indicated at 100. The wheel set 100 is shown in use with a track 150 which includes a base part 151 with a ribbed ground engaging surface 153 and a wheel engaging surface 155. The track further includes a series a drive lugs 156 which are generally centrally disposed and project from wheel engaging surface 155. The drive lugs 156 include lateral sides 157 and 158 having wheel bearing surfaces 160 and 161 which are disposed in guide planes X-X. The upper wheel engaging surface 155 is disposed in load bearing plane Y-Y.

The wheel set 100 includes a pair of spaced apart load sharing wheels 101 and 102 which operatively mounted on axle assembly 105 includes a central section 106 operatively connected to the vehicle track frame 110 and two stub axles 107 and 108 extending from the central section at an inclined angle relative thereto each stub axle having one of the wheels 101 and 102 mounted thereon for rotation about rotation axes Z-Z.

The load sharing wheels 101 and 102 include a rim section 112, the rim section including a load bearing portion 113 and a guide portion 114. Each wheel 101 and 102 may further include a covering 115 of elastomeric material on the rim section 112. There may further be provided a suitable bearing assembly 116 (only one is shown).

The axes of rotation Z-Z of the wheels 101 and 102 are inclined relative to one another and inclined to the longitudinal axis C-C of the central section 106 of the axle assembly 105 so that the load bearing portion 113 is in contact with the wheel engaging surface 155 of track 150 and the guide portion 114 will contact the lateral sides 157 and 158 of the drive lug 156 when it passes between the wheels 101 and 102. As shown the diametric axis D-D which is at right angles to axis of rotation of each wheel bi-sects the angle P between the guide plane X-X and the load bearing plane Y-Y.

By the above arrangement a component of rolling motion is achieved between the load bearing portion 113 and guide portion 114 of each wheel and the wheel engaging surface 155 and wheel bearing surfaces 160 and 161 of the track 150. When a track laying vehicle is in a high side load situation such as when it is traversing the side of a hill, extremely high side loads are applied between the guide portion 114 and the bearing surfaces 160 and/or 161. By producing a rolling action between the wheel guide portion 114 and the bearing surfaces 160 and/or 161 this results in a significant decrease in wear of the parts as a result of the reduction of side-load friction.

Finally, it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements of parts without departing from the spirit or ambit of the invention.

Claims

CLAIMS :

1. A load sharing wheel assembly which is suitable for use with a track for a track laying vehicle, the wheel assembly including at least one wheel set, the wheel set including two wheels which are spaced apart from one another so as to form a passage therebetween, each wheel having a rim section and being rotatable about an axis of rotation, said rim section including a primary load bearing portion and primary guide portion, the surface of each portion being generally disposed in respective planes which are inclined to one another and the rotation axis of each wheel being inclined to the planes of said portions.

2. A load sharing wheel assembly according to claim 1 which is suitable for use with a track assembly which includes a track with a base part having a ground engaging surface and a wheel engaging surface and a series of drive lugs spaced apart from one another along the length of the track and projecting from the wheel engaging surface, the drive lugs having lateral sides with wheel bearing surfaces thereon, the arrangement being such that when the belt moves past the load sharing wheel assembly there is a component of rolling movement between the guide portion of each wheel and the wheel bearing surfaces of the drive lugs.

3. A load sharing wheel assembly according to claim 1 or claim 2 wherein the rim section of each wheel is generally vee-shaped in cross-section one face defining the primary load bearing portion and the other face defining the primary guide portion.

4. A load sharing wheel assembly according to any preceding claim further including an axle assembly including a body portion operatively connected to the vehicle body and a pair of stub axles each being adapted to receive one of said wheels thereon, the stub axles being inclined downwardly and outwardly with respect to one another and with respect to the normal orientation of the vehicle.

5. A load sharing wheel assembly according to claim 4 wherein the axle assembly includes an intermediate or central section operatively connected to the vehicle body which the stub axle sections extending away from the intermediate section, the longitudinal axes of the stub axles being inclined to the longitudinal axis of the intermediate section.

6. A load sharing wheel assembly according to any preceding claim wherein said rim section of each wheel includes an elastomeric covering thereon.

7. A load sharing wheel assembly according to any preceding claim wherein each wheel is inclined at an angle which bi-sects the angle between the guide plane and the load bearing plane.