GB2187251A

GB2187251A - Drive transmission devices

Info

Publication number: GB2187251A
Application number: GB08530418A
Authority: GB
Inventors: Peter Windsor-Smith; Raymond Alfred Tailby
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-12-10
Filing date: 1985-12-10
Publication date: 1987-09-03
Also published as: GB8530418D0

Abstract

A combined drive input clutch and retarder device (10) for location between the engine and a conventional gear box of a road vehicle comprises interleaved friction elements (26-32) manually operable for gear change purposes, and coupled with these friction elements is an additional set of friction elements (30) which are non- rotatably coupled by a coupling (24) to the common housing (16) of the device whereby the latter can function both as a conventional input clutch and as a retarder located at the low torque end of the transmission. Oil cooling for the friction elements is provided. <IMAGE>

Description

SPECIFICATION Drive transmission devices This invention relates to drive transmission devices and to change speed gear trains incorporating such devices. Particularly, but not exclusively, the invention relates to gear trains for vehicles especially highway vehicles such as trucks and automobiles, in which a drive input clutch is provided between the prime mover and the gear train itself. For example, in the case of a conventional single layshaft manual shift gear box there is conventionally provided a drive input clutch between the internal combustion engine and the gear box itself. The present invention provides a drive transmission device for use in such a situation and which has wider applications in other drive transmission situations.

The present invention is technically related to our co-pending U.K. patent application number 84 12611 which is due to be published on 11th. December 1985 under serial number GB 2159897. The latter application is unpublished at the date of filing of the present application.

We hereby incorporate in the present application by reference the entire disclosure of our aforesaid prior application. In the latter application there is disclosed a clutch device for a change speed gear train such as a conventional manual shift single layshaft gear box for trucks. The drive transmission device of the present invention is suitable for use in place of the clutch device of our prior application in many if not all of the applications of the clutch device of our prior application.

The present invention is concerned with the provision of means for retarding a transmission. Presently available retardation equipment includes standard off-the-shelf retarder units.

In addition, it has been proposed to use a gear change clutch of a multi-layshaft gear train to provide retardation.

Problems raised by these prior proposals however include the fact that standard retarders tend to be large and expensive and heavy in view of the torques they are required to transmit. As regards the multi-layshaft retardation arrangements, these are satisfactory in themselves but such cannot be provided for ordinary single layshaft gear trains, and certain other gear trains. There is therefore a need for improvements relating to retarders for use in such situations and related transmissions.

An object of the present invention is to provide a drive transmission device offering improvements in relation to matters discussed above, or generally.

According to the invention there is provided a drive transmission device (10) comprising interleaved friction elements (26, 28, 30, 32), drive input and drive output means (21, 22) for the friction elements, and actuation means (34, 36) operable to cause the friction elements to drivably couple said drive input and drive output means, characterised by retardation coupling means (24) connected to said friction elements, the arrangement being such that said actuation means can be actuated to cause said friction elements to clutch to said retardation coupling means drive inputted to the transmission device thereby to retard said drive.

Preferably, a common housing (16) is provided for the drive transmission device. Said retardation coupling means may be in the form of non-rotatable coupling means connected to said housing.

Said friction elements may comprise an interleaved set of inner and outer clutch friction elements, and an interleaved set of inner and oute retarder friction elements, each set comprising friction elements drivably connected at their inner and outer peripheries. Either the inner friction elements or the outer friction elements of both sets thereof may be drivably coupled to a common drive member (21). Preferably, it is the inner friction elements of both sets which are drivably coupled to said common drive member (21). The two outer sets of friction elements (30, 32) may be coupled respectively to said retardation coupling means and to a second drive member (22).

Preferably, said common drive member (21) forms the drive output coupling of the transmission device (10).

Preferably, fluid cooling is provided for the friction elements. The cooling may be provided by fluid such as oil or the like supplied under pressure to the friction elements.

The invention also provides the drive transmission device as defined above in combination with a torque-increasing gear train.

The drive transmission device may be provided as an input clutch for the gear train. The gear train may comprise a single layshaft gear train with the drive transmission device mounted coaxially with the main shaft of the gear train as the drive input device thereto.

The invention also provides a drive transmission device and the combination of same with a change speed gear train comprising any novel feature or novel combination of features disclosed herein.

In an embodiment described below there is provided a drive transmission device for a change speed gear train. The drive transmission device comprises a common housing for at least three sets of interleaved friction elements. The friction elements include a nonrotatable set of friction elements coupled to the housing, together with a rotatable input set and a rotatable output set of friction elements. Actuator means is provided to enable clutchable engagement of the friction elements to provide both clutch and retarder functions.

In the embodiment, a drive transmission device is provided having multiple interleaved plate type friction elements providing both drive transmission clutch and retarder functions in a common housing. The drive transmission device is preferably employed in combination with a torque increasing gear train for a highway vehicle. The device. may be provided as the drive input coupling for the gear train.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows, diagrammatically, a schematic diagram of a drive transmission device according to the invention; and Figure 2 shows an embodiment of the device of Fig. 1 incorporated as the drive input clutch of a single layshaft gear train.

In the embodiment, the reference numerals are employed to designate parts as follows: 10 : drive transmission device 12 : input shaft 14 : output shaft 16 : housing 18 : input shaft bearing 20 : output shaft bearing 22 : coupling for clutch outer plates 24 : retardation coupling member 26 : inner clutch plates 28 : inner retarder plates 30 : outer retarder plates 32 : outer clutch plates 34 : clutch actuator 36 : retarder actuator 38 I fixing bolts for retarder coupling 40 : inputjoutput shaft joint Input shaft 12 is directly coupled to the crankshaft of an engine (not shown) in a drive transmission of a conventional highway truck.

Output shaft 14 is coupled to the input shaft of a conventional single layshaft change speed gear train of the manual shift kind. Shaft 14 is coaxial with the gear box main shaft.

Input shaft 12 is fixed to a carrier 22 for a set of annular clutch friction elements of the conventional sintered metal kind or the like for sliding engagement with other similar sets of friction elements under the control of actuators 34, 36. The other clutch plates are an inner set 26 slidably dogged to a drive output member 21 which also carries a set of retarder plates 28 interleaved with a set of outer retarder plates 30 arranged for actuation by an actuator 36.

The actuators 34, 36 are conventional fluid pressure actuators serving to compress their respective assemblies of friction elements for drive transmission purposes. The actuators are independently operable under driver control.

The retardation coupling member 24 is secured by a ring of bolts 38 to housing 16 so as to be non-rotatable therewith.

Operation of the drive transmission device will now be described.

In use, drive is transmitted from the engine via input shaft 12 to input coupling 22 and hence to the outer set of clutch plates 32 which are dogged thereto. The inner set of clutch plates 26 and 28 dogged to output coupling 21 are at this stage not rotating.

Likewise, the outer set of clutch plates 30 dogged to the retarder coupling 24 are of course also not rotating. Output shaft 14 is also not rotating.

Operation of actuators 34 causes frictional engagement of the clutch plates 32 and 26 for transmission of drive between members 22 and 21 and hence to output shaft 14. In this way, drive is transmitted to the output shaft in the manner of a conventional clutch, and all the time that actuators 36 are not operated, the drive transmission device 10 functions as a conventional clutch and drive is transmitted to output shaft 14 and hence through the gear train to the ground wheels of the vehicle.

Upon operation of actuators 36 for retardation purposes, drive from the output coupling 21 is transmitted to the non-rotating set of outer clutch plates 30 whereby retardation of the output coupling and output shaft 14 is effected. Oil under fluid pressure is fed to the clutch plates in the conventional manner to produce cooling thereof and prevent direct face to face physical engagement of the plates. Heat generated during retardation is thereby dispersed and oil cooling means may be provided to cool the oil before it is returned to the transmission device.

It is of particular significance that the transmission device 10 is located at the input end of the gear train between the gear train and the engine whereby drive input to the device is at engine torque and engine speed.

Hitherto, it has been conventional to provide retarders, in the form of specific individual bolt on assemblies at a location between the gear box of a vehicle and the ground wheels. At that location the drive input to the retarder is slower and at a higher torque and thus the retarder itself is required to be of considerable size and bulk and therefore of considerable cost.

By locating the retarder in a common housing with the input clutch assembly, considerable economies of space and original construction costs are achieved by common use of components and supports and indeed common supply of cooling fluid. Moreover, the retarding effect of the retarder is greatly enhanced by the step-down in torque which occurs between the retarder and the ground wheels in all ratios except the upper gear or gears.

In this manner, there has been provided a compact and economical clutch and retarder assembly offering considerable advantages in many vehicle applications, particularly public service vehicles.

Claims

1. A drive transmission device (10) comprising interleaved friction elements (26, 28, 30, 32), drive input and drive output means (21, 22) for the friction elements, and actuation means (34, 36) operable to cause the friction elements to drivably couple said drive input and drive output means, characterised by retardation coupling means (24) connected to said friction elements, the arrangement being such that said actuation means can be actuated to cause said friction elements to clutch to said retardation coupling means drive inputted to the transmission device thereby to retard said drive.

2. A drive transmission device according to claim 1 characterised in that a common housing (16) is provided for the drive transmission device.

3. A drive transmission device according to claim 2 characterised in that said retardation coupling means is in the form of nonrotatable coupling means connected to said housing.

4. A drive transmission device according to any one of the preceding claims characterised in that said friction elements comprise an interleaved set of inner and outer clutch friction elements (26, 32), and an interleaved set of inner and outer retarder friction elements (28, 30), each set comprising friction elements drivably connected at their inner and outer peripheries.

5. A drive transmission device according to claim 4 characterised in that the inner or the outer friction elements of both said sets of friction elements are drivably coupled to a common drive member (21).

6. A drive transmission device according to claim 5 characterised in that the inner friction elements of both sets are drivably coupled to said common drive member (21).

7. A drive transmission device according to claim 6 characterised in that the two outer sets of friction elements (30, 32) are coupled respectively to said retardation coupling means and to a second drive member (22).

8. A device transmission device according to any one of claims 5 to 7 characterised in that said common drive member (21) forms the drive output coupling of the transmission device (10).

9. A drive transmission device according to any one of the preceding claims characterised in that fluid cooling is provided for said friction elements.

10. A drive transmission device according to claim 9 characterised in that said fluid cooling is provided by oil or the like supplied under pressure to said friction elements.

11. A drive transmission device substantially as described herein with reference to the accompanying drawings.

12. A drive transmission device according to any one of the preceding claims in combination with a torque-increasing gear train.

13. The combination claimed in claim 12 characterised in that said drive transmission device is provided as an input clutch for said gear train.

14. The combination of claim 13 characterised in that said gear train comprises a single layshaft gear train with said drive transmission device mounted coaxially with the main shaft of the gear train as the drive input device thereto.