GB2275511A

GB2275511A - Vehicle transmission and auxiliary drive driven by a shaft passing through hollow shaft and driven by a torque converter impeller

Info

Publication number: GB2275511A
Application number: GB9304007A
Authority: GB
Inventors: Alan Griffiths; Kirk Burwell
Original assignee: Dana Ltd
Current assignee: Dana Ltd
Priority date: 1993-02-27
Filing date: 1993-02-27
Publication date: 1994-08-31
Also published as: GB9304007D0

Abstract

A gearbox and torque converter for a heavy duty vehicle includes a hollow drive shaft (26) rotatably drivable by the turbine (24) of the torque converter (10), the impeller (12) being driven directly by the vehicle engine. The shaft (26) drives clutch housings (32, 34) of respective clutch packs (28, 30) for forward or reverse motion drive of the vehicle. An auxiliary drive or power take off shaft (44) is rotatably drivable by the impeller and extends through the gearbox within the hollow shaft (26) and through the clutch packs to an output end externally of the gearbox. An auxiliary drive device such as an hydraulic pump (48) is mountable at the rear of the gearbox coaxial with the torque converter for direct drive by the shaft (44). <IMAGE>

Description

TITLE: Vehicle Transmission and Auxiliary Drive This invention relates to a motor vehicle transmission and drive means for an auxiliary drive device.

Many motor driven vehicles, especially heavy duty primarily off-road vehicles, are equipped with auxiliary drive devices. For example, agricultural tractors are generally equipped with an auxiliary power take-off shaft for mechanical driving connection to an implement towed by the tractor, and backhoe loaders are equipped with an auxiliary drive shaft to a hydraulic pump for powering the vehicle hydraulics.

The drive to such auxiliary drive devices generally comprises an auxiliary drive shaft driven directly from the vehicle prime mover. Such an auxiliary drive shaft is driven directly from the vehicle engine so that the drive shaft speed of such auxiliary drive shaft is dependent directly on the engine speed and not on the speed of an output from the vehicle gearbox. It will be appreciated that frequently it is required to drive the auxiliary drive device when the vehicle is stationary and thus the auxiliary drive shaft speed cannot be dependent upon the output from the vehicle main gearbox. Hence it has been necessary to provide transfer gearing to drive the auxiliary drive device with such transfer gearing being driven directly from the engine. The provision of such transfer gearing is both space and weight consuming.

One known arrangement of vehicle transmission and drive means for an auxiliary drive device comprises a torque converter and gearbox and an auxiliary drive device comprising a hydraulic pump mounted above the gearbox, transfer gearing and an auxiliary drive shaft being mounted externally of the gearbox between the input side i.e. the vehicle engine side of the gearbox and the pump. In such an arrangement the auxiliary drive device may be driven via the transfer gearing and auxiliary drive shaft from the impeller of the torque converter whereas the vehicle transmission is driven from the output side of the gearbox from the turbine of the torque converter.

It is an object of the present invention to provide a motor vehicle transmission and auxiliary drive means which will offer space and weight saving advantages in comparison with known such devices.

In accordance with one aspect of the invention there is provided a motor vehicle transmission comprising a gearbox and a torque converter having an impeller drivable by a vehicle engine and a turbine driven by said impeller; a hollow drive shaft within the gearbox connected for torque transmission between the turbine and at least one clutch pack; and an auxiliary drive shaft connected at one end to said impeller and extending within the gearbox coaxially within said hollow drive shaft and through said clutch pack to an output end thereof externally of said gearbox.

Preferably two dutch packs are provided in coaxial relationship with one another, said hollow drive shaft being connected for torque transmission between the turbine and both of said clutch packs, and said auxilary drive shaft extending within said hollow drive shaft through both of said clutch packs.

One of such clutch packs is selectively operable to transmit or disconnect forward motion drive from said drive shaft to an output shaft of the gearbox and the other of such clutch packs is selectively operable to transmit or disconnect reverse motion drive from said drive shaft to said output shaft of the gearbox. The clutch packs each comprise a clutch housing and clutch plates within the housing, the housing of each said clutch pack conveniently being mechanically connected to and driven by said hollow drive shaft.

With such an arrangement it will be appreciated that the auxiliary drive device may be driven from the rear end of the gearbox by a said output end of the auxiliary drive shaft which is coaxial with the torque converter impeller turbine. Thus, for example, if it is desired to drive an auxiliary hydraulic pump such pump may be mounted directly at the rear of the vehicle gearbox coaxially with the torque converter which is at the front of the gearbox. Thus no transfer box or auxiliary drive shaft is necessary externally of the gearbox casing thereby resulting in a compact and weight saving arrangement of transmission and auxiliary drive means.

Other features of the invention will become apparent from the following description given herein solely by way of example with reference to the accompanying drawing which shows, in simplified form, a side cross-sectional view of a vehicle transmission comprising a torque converter and gearbox including drive means for an auxiliary drive device in accordance with the invention.

The transmission shown in the drawing has, at its front or input end, a torque converter unit 10 comprising an impeller 12 driven directly from an output shaft 14 of the vehicle engine. The impeller 12, which comprises the casing of the torque converter, is mechanically connected to the shaft 14 by means of a bracket connector 16 and bolts 18, 20 whereby the impeller is rotatable with the shaft 14. An oil pump 22 is connected at the rear end of the torque converter for rotation with the impeller 12 at engine speed, the pump 22 providing pressurised transmission fluid to the transmission and torque converter. In known manner, the impeller 12 drives a turbine 24 at a rotational speed varying in accordance with the vehicle's resistance to motion.

A hollow transmission input drive shaft 26 is connected at its front end to the turbine 24 and is rotatable therewith, the shaft 26 extending rearwardly through the gearbox casing coaxial with the impeller 12, turbine 24 and engine output shaft 14. Within the gearbox casing there are provided two coaxial clutch packs 28 and 30 each of which has a respective clutch housing 32, 34 fast with the drive shaft 26 so as to be rotatable therewith upon drive from the turbine 24.

Each of said clutch packs is of generally conventional form having two sets of interleaved clutch plates therein whereby when the plates of one clutch pack 28 are in engagement with one another and the housing 32 is driven for rotation by the drive shaft 26, forward motion is imparted to the vehicle and when the clutch plates of the other clutch pack 30 are in engagement with one another and the housing 34 is driven, reverse motion is imparted to the vehicle.

As is illustrated schematically in the drawing the clutch pack 28 at the forward end of the gearbox is operable to impart forward motion drive to the vehicle via a drive gear 36 and intermediate gearing (not shown) to an output shaft 38 at the rear of the gearbox. A drive gear 40 of the other clutch pack 30 is operable to impart drive through gearing (not shown) to impart reverse motion drive to the output shaft 38. In the drawing there is illustrated further transfer gearing to a secondary output shaft 42 in the case of a requirement for a fourwheel vehicle drive.

In accordance with the invention the drive shaft 26 is hollow and, within said drive shaft, there is coaxially arranged an auxiliary drive shaft 44 connected at its forward end 46 via the torque converter impeller 12 to the engine output shaft 14. Thus the auxiliary drive shaft 44 is always driven at engine speed irrespective of the speed of rotation of the drive shaft 26 or of either of the output shafts 38, 42 of the gearbox. The auxiliary drive shaft 44 extends rearwardly through the gearbox within the hollow shaft 26 and at the rear end of the gearbox housing the auxiliary drive shaft 44 provides an output auxiliary drive means to drive, as illustrated in this embodiment, a hydraulic pump 48 connected directly to the rear of the gearbox housing coaxial with the torque converter 10.

Although a hydraulic pump is illustrated in the drawing it will be appreciated that the auxiliary drive shaft may drive a mechanical power take-off.

Thus the whole of the auxiliary drive means is contained within the torque converter and gearbox thereby effecting considerable saving in space and enabling the auxiliary drive device, whether it be hydraulic or mechanical, to be taken directly from the rear of the gearbox coaxial with the torque converter.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A motor vehicle transmission comprising a gearbox and a torque converter having an impeller drivable by a vehicle engine and a turbine driven by said impeller; a hollow drive shaft within the gearbox connected for torque transmission between the turbine and at least one clutch pack; and an auxiliary drive shaft connected at one end to said impeller and extending through the gearbox within said hollow drive shaft and through said clutch pack to an output end externally of said gearbox.

2. A motor vehicle transmission as claimed in claim 1 wherein two clutch packs are provided in coaxial relationship with one another, said hollow drive shaft being connected for torque transmission between the turbine and both of said clutch packs, and said auxiliary drive shaft extending within said hollow drive shaft through both of said clutch packs.

3. A motor vehicle transmission as claimed in claim 2 wherein one of said two clutch packs is selectively operable to transmit or disconnect forward motion drive from said hollow drive shaft to an output shaft of the gearbox and the other of said clutch packs is selectively operable to transmit or disconnect reverse motion drive from said hollow drive shaft to said output shaft of the gearbox.

4. A motor vehicle transmission as claimed in any one of the preceding claims wherein the or each said clutch pack comprises a clutch housing and clutch plates within the housing, the housing of said clutch pack being mechanically connected to and driven by said hollow drive shaft.

5. A motor vehicle transmission as claimed in any one of the preceding claims including an auxiliary drive device mounted at the rear of the gearbox and being drivable by said output end of said auxiliary driveshaft.

6. A motor vehicle transmission as claimed in claim 5 wherein said auxiliary drive device comprises an hydraulic pump.

7. A motor vehicle transmission as claimed in claim 5 wherein said auxiliary drive device comprises a mechanical power take-off means.

8. A motor vehicle transmission comprising a gearbox and a torque converter constructed and arranged substantially as hereinbefore described with reference to the accompanying drawing.

9. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.