GB2221434A

GB2221434A - Drive axle assembly

Info

Publication number: GB2221434A
Application number: GB8917462A
Authority: GB
Inventors: Terence Sydney Harrison
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-08-04
Filing date: 1989-07-31
Publication date: 1990-02-07
Anticipated expiration: 2009-07-31
Also published as: GB2221434B; GB8917462D0; GB8818555D0

Abstract

A drive axle assembly comprising a shaft 16 supported by a bearing 18 substantially centrally in a triangular plate 20 which is mounted by its upper apex to an upper chassis member 10 and its lower apices to a lower chassis member 12. The end of the shaft 16 mounts a coupling flange 46 which is connected by a coupling 48 to a further coupling flange 44. The coupling 48 comprises a rigid circular casing which encloses four bonded rubber ball joints 50, 90 DEG spaced apart. The flange 46 is secured to one opposed pair of the joints 50 and the flange 44 is secured to the other opposed pair of the joints 50. The flange 44 is formed on a wheel hub shaft 26 which mounts a wheel 14. The hub shaft 26 is rotatably supported within a mounting 28 which is adjustably mounted on the upper and lower chassis members 10, 12 allowing the wheel 14 to be movable, providing for alteration to the camber and toe in or toe out thereof. <IMAGE>

Description

Improvements relating to Drive Axle Assemblies This invention is concerned with improvements in/and relating to drive axle assemblies and particularly rear axle assemblies for racing karts.

Conventionally the rear drive axle on a kart is mounted directly on the kart chassis and requires to take the weight of the kart together with the weight of the driver. As a consequence -such conventional drive axles bend under load.

Further there are no provisions on conventional racing karts for the rear wheels to be set at different angles so as to enable alteration of the camber and the toe in of the rear wheels, racing kart regulations preventing conventional suspensions from being used.

It is an object of the present invention to provide an improved form of drive axle assembly which is particularly useful in racing karts to meet the disadvantages as outlined above.

According to the present invention there is provided a drive axle assembly comprising a drive shaft, means providing a bearing for the drive shaft and for mounting the latter on a chassis at a plurality of locations spaced from the shaft axis, means for rotatably supporting a wheel hub arrangement and for mounting the latter on the chassis, and means for drivingly coupling the wheel hub arrangement to the drive shaft.

Preferably the mounting means for the drive shaft comprises a plate which is adapted to be securely fixed to chassis members positioned above and below the shaft axis, relating to the disposition in use. The mounting plate may have a triangular configuration, adapted to be secured at one apex to the upper chassis member and at the other apices to the lower chassis member.

Preferably also the coupling means comprises a rubber bushed coupling, to one side of which is secured a coupling flange on the drive shaft, and to the other side of which is secured a coupling flange on the wheel hub arrangement. The coupling may comprise a rigid casing which encloses four rubber ball joints at locations spaced 900 apart, the coupling flange of the drive axle being secured to the ball joints at one opposed pair of the locations, and the coupling flange of the wheel hub arrangement being secured to the ball joints at the other opposed pair of the locations.

Further, the wheel hub mounting means may be connected to the chassis by spherical rod end bearings whereby the wheel hub arrangement may be movable in the connections to provide adjustment to the camber and toe in or toe out of a respective wheel. The wheel hub mounting is preferably adapted to be connected to a pair of chassis members spaced above and below the hub axis relative to the disposition in use, with one connection to the upper chassis member and two connections to the lower chassis member in a triangular configuration.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Fig. 1. is a rear view in part section of the rear wheel assembly of a racing kart; Fig. 2. is a top plan view in part section of the rear wheel assembly of Fig. 1.

The drawings show only part of the chassis of the racing kart in the form of vertically spaced upper and lower horizontal chassis members 10, 12 respectively, located to the rear and to one side of the kart, with an associated rear wheel 14.

A transverse rear drive shaft 16 is supported at each fetid (only one end shown in the drawings) by a suitable bearing 18, substantially centrally iti a plate 20 of generally triangular shape. The plate 20 is preferably formed of aluminium, having one side horizontal and secured at respective end locations along said one side on the lower chassis member 12 by means of bolts 22 e igagi tig internally threaded bosses 24 oti the chassis member 12: At its upper apex the plate 20 is similarly secured to the upper chassis member 10.The drive shaft 16 extends through the plate 20 towards the platie common to the chassis members 10, 12 for a purpose hereinafter described.

The wheel 14 has a hub shaft 26 which is rotatably supported within a mounting 28, the latter having a sleeve 30 swithin which the hub shaft 26 is mounted by a suitable bearing and a pair of laterally spaced mounting arms 32 which are substantially vertically arranged. At the lower elides the arms 32 have ati i interconnecting horizontal bar extending laterally beyond each of the arms 32 and being internally threaded to receive a securing bolt 34 which extends through, to collect with, a spherical rod etid bearirig 36.The bearings 36 are secured to the lower chassis member 12 by means of threaded mounting sections 38 engagillg ill internally threaded bosses 40. The latter are aligtied with the bosses 24 oii opposite sides of the lower chassis member 12. At their upper ends the arms 32 are interconnected by a bolt 42 which, between the arms 32, extends through, to connect with, a further spherical rod bearing 36 which is similarly secured to the upper chassis member 10 in alignment with the securing location of the bearing plate 20'.

The wheel hub shaft 26 extends inwardly of the mounting 28 and at its inner end has a coupling flange 44.

At its inner end the drive shaft 16 is also provided with a coupling flange 46, the flanges 44, 46 being secured to respective sides of a coupling 48. The latter is formed of a rigid circular casing which encloses four bonded rubber ball joints 50, 900 spaced apart. The flange 44 is secured by bolts 52 to one opposed pair of the joints 50, while the flange 46 is secured by means of bolts 54 to the other opposed pair of the joints 50.

The drive shaft 16 carries a sprocket (not shown) which connects to an engine sprocket by a suitable chain.

The shaft 16 also carries a disc for a rear brake. The design of connection to the chassis is such that the drive shaft 16, in use, transmits only the drive and braking forces and does not take the weight of the kart and the driver, thus obviating or mitigating bending of the drive shaft.

The mounting of the mounting 28 in the spherical rod erid bearings 36 allows the hubs and therefore the wheels 14 to be movable, whereby to be capable of being set at different angles, providing for al teratioti to the camber aiid toe iri of the rear wheels. This provides the kart with improved corllerilig performance. When the. camber, toe in or toe out is being adjusted, this is achieved entirely by means of the adjustable hubs and the bonded rubber ball joints of the coupling 48, with no movement of the drive shaft 16.The bonded rubber ball joints of the coupling 48 permit a coiit i nuous angle of 50 to be used while running, the ball joints being the only flexible parts of the drive system oiice the wheels have been adjusted and set to the desired arigl e.

It should be appreciated that other forms of coupling may be utilised such as a 4, 6 or 8 sided arinular angular unit hay rig metal iiiserts bonded in position. Such coupling are possible due to the mounting a rrarigemeiit of the drive axle system not requiririg a cardari shaft or celltering device between the drive axle arid the hub shafts, thus allowing high speeds to be obtained.

A spacer could be provided aground the shaft 16 extending between the bearings 18 for each wheel o the shaft 16. This spacer would be fitted to bear the forces applied when the flange 46 is secured to the drive shaft 16, usually by a bolt. Otherwise these forces are borne entirely by the mounting of the respective bearing 18 on the shaft 16, usually a grub screw, which may not allow sufficient tightening of the flange 16 for a firm assembly. Various other modifications may be made without departing from the invention. For example the configuration of the various components may differ from that described and shown provided the assembly functions as necessary.

Claims

1. A drive axle assembly comprising a drive shaft, means providing a bearing for the drive shaft and for mouriti1ig the latter on a chassis at a plurality of locations spaced from the shaft axis, means for rotatably supporting a wheel hub arrangement and for mounting the latter o the chassis, and means for drivingly couplirig the wheel hub arrangement to the drive shaft.

2. A assembly accordirig to claim 1, iri which the mounting means for the drive shaft comprises a plate which is adapted to be securely fixed to chassis members positioned above and below the shaft axis, relating to the disposition in use.

3. Ari assembly according to claim 2, in which the mouriting plate has a triangular configuration, adapted to be secured at one apex to the upper chassis member aid at the other apices to the lower chassis member.

4. Ai1 assembly according to ariy of claims 1-3, i which the coupling means comprises a rubber bushed coupling, to one side of which is secured a coupling flange on the drive shaft, arid to the other side of which is secured a coupling flange on the wheel hub arrangement.

5. Ai1 assembly according to claim 4, in which the coupling comprises a rigid casing which encloses four rubber ball joints at locations spaced 900 apart, the coupling flange of the drive axle being secured to the ball joints at one opposed pair of the locations, and the coupl i rig flange of the wheel hub arrangement being secured to the ball joints at the other opposed pair of the locatioris.

6. An assembly according to ariy of the preceding claims, in which the wheel hub mounting means is connected to the chassis by spherical rod erid bearings whereby the wheel hub arrangement may be moveable in the connections to provide adjustment to the camber and toe in or toe out of a respective wheel.

7. Ari assembly according to any of the preceding claims, in which the wheel hub mounting is adapted to be connected to a pair of chassis members spaced above and below the hub axis relative to the disposition i use, with oe coririoctioii to the upper chassis member and two connections to the lower chassis member in a triangular configuration.

8. A drive axle assembly substantially as hereinbefore described with reference to the accompanying drawings.

9. Ay novel subject matter or combination including novel subject mater herein disclosed in the foregoing specification or claims and/or shown iri the drawings, whether or riot within the scope of or relating to the same i riverition as any of the preceding claims.