WO2004063599A1

WO2004063599A1 - Power divider assembly

Info

Publication number: WO2004063599A1
Application number: PCT/AU2004/000044
Authority: WO
Inventors: Garry Rose
Original assignee: Kinetic Engineering Services Pty Ltd
Priority date: 2003-01-14
Filing date: 2004-01-14
Publication date: 2004-07-29
Also published as: AU2003900144A0

Abstract

A power divider assembly (1) including a drive input (6); first and second outputs (7, 8) arranged to be coupled to associated first and second axles (11, 12) of a vehicle (10); and a differential (20) including first and second couplers (24, 25) for transmitting torque to the first and second outputs, respectively, the couplers being driven in unison and each coupler being adapted to be individually moved out of driving engagement when the couplers rotate at different speeds.

Description

POWER DIVIDER ASSEMBLY

Field of the Invention

The present invention relates to a power divider assembly particularly, but not exclusively, for driving axles of a vehicle.

Background of the Invention

It is known to provide an open differential between a mid and rear axle of a multi-axle vehicle so that a drive system can deliver the same drive torque to each of the axles, whilst allowing the axles to rotate independently. An open differential is ideal for driving on roads but when driving conditions become more difficult, such as in an off-road environment, the open differential needs to be locked so that the axles are effectively coupled together.

The differential, in a locked condition, causes torque from the drive system to be transmitted equally to the inputs of the mid (first) and rear (second) axles. As such, the locked differential acts as a power divider, insofar as power, or torque, is divided equally between the axles, independent of associated wheel traction, whereas the open differential directs torque to the axle with least resistive load.

Placing the differential in a locked condition involves actuation of a locking mechanism such as by manually engaging a lever. A disadvantage of such a mechanism is that the vehicle needs to be stopped, before the locking mechanism is engaged. A further disadvantage is that the locking mechanism may be inadvertently left in the engaged condition after the vehicle transits from an off-road to a sealed road environment.

Object of the Invention

The present invention seeks to address the above disadvantages.

Summary of the Invention

hi accordance with the invention, there is provided a power divider assembly including: a drive input;

a first and second output arranged to be coupled to associated first and second axles of a vehicle, which are spaced apart in a lengthwise direction of the vehicle; and

a differential including first and second couplers for transmitting torque to the first and second outputs, respectively, the couplers being driven in unison and each coupler being adapted to be individually moved out of driving engagement when the couplers rotate at different speeds.

Preferably, the differential includes a housing, within which the couplers are arranged, and the drive input forms a component of the housing.

Preferably, the couplers rotatably drive concentrically arranged elements which are in turn coupled to and drive a respective one of the outputs.

Preferably, the assembly includes a clutch device to dampen backlash between the elements when the associated couplers move back into driving engagement. More preferably, the device includes a pre-loaded tapered cone on one of the elements, arranged in biased relation to a complementary surface on the other element.

Preferably, the outputs extend from a side of the differential, opposite the drive input.

Preferably, the drive input includes a drive wheel, extending radially inwardly of the housing, the drive wheel being provided between the couplers and having teeth arranged to interfit with corresponding teeth of each coupler, for driving the respective outputs.

Brief Description of the Drawings

The invention is described in more detail, with reference to the accompanying drawings, in which:

Figure 1 is a plan view of a power divider assembly;

Figure 2 is a diagrammatic side view of a vehicle; Figure 3 is a diagrammatic plan view of part of a vehicle chassis; and

Figure 4 is a cross-section view of the power divider assembly.

Detailed Description

Referring firstly to Figure 1, a power divider assembly 1 is shown as including an assembly casing 2 formed of a main housing 3, a bearing housing 4 and a chain housing 5. The assembly also includes a drive input 6 and first and second outputs 7, 8.

In Figures 2 and 3, the assembly 1 is shown mounted to a chassis 9 of a vehicle 10. The drive input 6 is coupled to an engine tail shaft 13 and the first and second outputs 7, 8 are connected to respective first and second axles 11, 12, which are spaced apart in a lengthwise direction of the vehicle 10.

Power is transferred from the input 6, through the assembly 1, to first and second axles 11, 12 by intermediate linkages 14, 15 and respective differentials 16, 17, in order to drive associated wheels 18, 19 mounted to the axles 11, 12.

The power or torque delivered to the axles 11, 12 is divided by the assembly 1, in order to ensure equal torque is applied to wheels 18, 19. For that purpose, the assembly 1 is provided with a positive-acting differential 20 (see Figure 4), which locks the outputs 1, 8 together in normal operation and selectively releases one of the outputs from driving engagement in a situation where one output is rotating at a different rate relative to the other.

The differential 20 is formed of two housing components 21, 22 which define a cavity 23 for receipt of the couplers 24, 25. The first component 21 is formed of the drive input 6 itself and carries a drive wheel 26 which extends radially inwardly, between each of the couplers 24, 25, while the second component 22 is rotatably mounted on bearings 27 in the housing 3. Springs 30 are provided in the cavity 23 to bias the couplers 24, 25 toward the drive wheel 26, to cause corresponding teeth (not shown) on each of the couplers 24, 25 and the drive wheel 26 to intermesh for driving engagement.

The couplers 24, 25 are mounted, with limited axial movement, to respective co-axial elements 28, 29 which connect the couplers 24 , 25 to associated outputs 7, 8. More specifically, the first element 28 connects through a connecting gear 46 to the first coupler 24 of the differential 20 and the first output 7. The second element 29 extends from the second coupler 25, partway along the length of the first element 22, and has a cog wheel 30 which drives an endless chain 31 through the chain housing 5, in order to rotate an associated cog wheel 32 in the housing 4. The wheel 32 is integrally formed with a rotatable shaft 33 which is mounted on bearings 34 and which is directly coupled to the second output 8. The shaft 33 can, of course, instead be used to direct torque forward to an alternative second output or, indeed, be used for torque transmission both forwardly and rearwardly.

As such, rotation of the couplers 24, 25 in unison results in the outputs 7, 8 also rotating in unison. If, however, one of the couplers 24, 25 is caused to rotate at a different rate relative to the other, it will be forced away from the drive wheel 26 by reactive forces between the teeth, against the relevant spring bias and that will in turn disengage the associated element 28, 29 from driving engagement until the rotational speeds of the couplers are again matched.

When the couplers 24,25 are again re-engaged, or in a situation between drive on and drive off, a degree of backlash may occur and a clutch device 40 is installed to dampen that affect. The device 40 is in the form of a tapered cone 41, provided on the element 28. The cone 41 has a multistart thread 42 on its external surface 43, for lubrication, and is held in preloaded relation with a complementary surface 44 formed internally of the concentrically arranged element 29. The preloading is effected by bias force exerted by spring or belleville washers 45, which force the clutch device 40 into engagement with the element 29, to maintain a resistive force between the outputs, so as to provide the required dampening affect.

Accordingly, the assembly 1 allows for power to be divided equally between both outputs 7, 8, as required, whilst the application of power or torque to one of the axles 11, 12 may be automatically interrupted if that axle starts spinning at a different rate relative to the other axle. The torque can then be relatively smoothly reapplied when the couplers 24,25 re-engage, by virtue of clutch device 40.

Another advantage of the assembly 1 is that the drive input 6 actually forms part of the differential housing and that reduces component parts and simplifies the overall construction of the differential 20. A further advantage associated with the construction of the assembly 1 is that both the first and second co-axial elements 28, 29 extend away from the input 6, and that positions both outputs 7, 8 on a side of the differential 20 opposite the drive input 7. Such an arrangement allows the differential 20 to be readily installed and accessed for maintenance.

The invention has been described by way of example only and many modifications and variations may be made thereto without departing from the spirit and scope of the invention described.

Claims

The claims:

1. A power divider assembly including: a drive input; a first and second output arranged to be coupled to associated first and second axles of a vehicle, which are spaced apart in a lengthwise direction of the vehicle; and a differential including first and second couplers for transmitting torque to the first and second outputs, respectively, the couplers being driven in unison and each coupler being adapted to be individually moved out of driving engagement when the couplers rotate at different speeds.

2. A power divider assembly as claimed in claim 1 , wherein the differential includes a housing, within which the couplers are arranged, and the drive input forms a component of the housing.

3. A power divider assembly as claimed in claim 1 or 2, wherein the couplers rotatably drive concentrically arranged elements which are in turn coupled to and drive a respective one of the outputs.

4. A power divider assembly as claimed in any one of claims 1 to 3, wherein the assembly includes a clutch device to dampen backlash between the elements when the associated couplers move back into driving engagement.

5. A power divider assembly as claimed in claim 4, wherein the device includes a pre- loaded tapered cone on one of the elements, arranged in biased relation to a complementary surface on the other element.

6. A power divider assembly as claimed in any one of claims 1 to 5, wherein the outputs extend from a side of the differential, opposite the drive input.

7. A power divider assembly as claimed in claim 2, wherein the drive input includes a drive wheel, extending radially inwardly of the housing, the drive wheel being provided between the couplers and having teeth arranged to interfit with corresponding teeth of each coupler, for driving the respective outputs.