GB1583951A - Clutches - Google Patents

Description

(54) IMPROVEMENTS RELATING TO CLUTCHES (71) We, GKN TRANSMISSIONS LTD., a British Company of Chester Road, Erdington, Birmingham B24 ORB, West Midlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to friction clutches of the dual clutch type and including two sections for respectively coupling a common input shaft to two coaxial output shafts, and with which is associated a release mechanism operative to free one of the clutch sections or both or them. Such clutches will hereafter be referred to as clutches of the kind specified.

It is common to design clutches of the kind specified to operate in the pressure of a fluid such as oil, for the purpose of assisting dissipation of frictionally generated heat from the clutch and for lubrication. Such fluid may be circulated by a system which introduces the fluid into a central region of the clutch from where it flows generally radially outwardly under centrifugal force arising from the rotation of the clutch.

A problem which can arise in a clutch equipped with such a circulation system is that the distribution of fluid between the two sections of the clutch can become uneven, particularly when one section is disengaged whilst the other remains engaged. In this condition the disengaged section can present an easier outward flow path for the fluid, and the engaged section can be without an an adequate fluid supply.

The present invention provides a dual friction clutch including two sections for respectively coupling a common input shaft to two output shafts and having an annular groove located radially inwardly of torquetransmitting components of the two sections, the groove having an inwardly directed annular opening into which, in use fluid for distribution to the two sections is introduced, such distribution being effected by two sets of fluid directing means arranged to discharge fluid from the groove under the influence of centrifugal force into two separated open spaces in the interior of the clutch such that fluid from one set is directed through one open space towards one section and fluid from the other set is directed through the other open space towards the other section of the clutch.

Because both sets of fluid directing means discharge into open space, the engaged or disengaged state of the clutch sections cannot influence the division of fluid between the two sections of the clutch and a regular division of fluid between the two sections is thus assured.

The invention has been developed in relation to a clutch of the kind specified in which each section of the clutch comprises a driving member, an axially movable presser member, and a driven member adapted to be driven by being clamped between the driving member and presser member. Thus, the driving member of the first section, incorporating the annular groove on the opposite side thereof from the driven member, may be connected to an output shaft of a prime mover, and may constitute a flywheel for such prime mover, the driving member of a second section being connected to the driving member of the first section.

As applied to a clutch of this kind, the invention provides that the driving member of the first section may be provided with generally axially extending passage means through which fluid is introduced into the inner region of the clutch, and the fluid directing means may co-operate therewith to provide for discharge of fluid to two axially spaced regions, from which fluid can flow to the two sections of the clutch.

Where the driving member of the first section constitutes a flywheel of the clutch, the passage means may be provided by a plurality of angularly-spaced apertures extending through the flywheel, the fluid directing means comprising a member cooperating with some of the apertures to direct fluid emerging therefrom to one region, and with others of the apertures to direct fluid emerging therefrom to the other region.

The invention will now be described by way of example with reference to the accompanying drawings, of which: FIGURE 1 is a longitudinal section through a clutch of the kind specified, embodying the invention, and FIGURE 2 is a view similar to Figure 1, but on an enlarged scale, Referring firstly to Figure 1, the illustrated clutch is shown as being connected to an output shaft 11 of a prime mover, such as an internal combustion engine, by bolts 12.

The clutch has two sections respectively for driving two concentric output shafts, the first section of the clutch comprising a driving member in the form of a plate 10, an axially movable presser member in the form of a plate 13, and a driven member in the form of a friction plate 14 which is clamped between the driving plate 10 and presser plate 13 when the first section of the clutch is engaged. The driving plate 10 provides a flywheel of the clutch, and driven plate 14 is connected to an internally splined boss 15 by which the first section of the clutch may be connected to an output shaft. The other section of the clutch comprises a driving member in the form of a plate 16 rotationally connected to the driving plate 10, a presser plate 17, and a driven member comprising friction plates 18a, 18b, arranged to be clamped between the driving plate 16 and presser plate 17 and which are connected to a splined boss 19 by which the second section of the clutch may be connected to a second output shaft. A plate spring 9 is provided for urging the presser plate 17 into its engaged position, and a plurality of coil compression springs 8 act on the presser plate 13 to urge it into engagement with driven plate 14.

The clutch is provided with a release mechanism for effecting seqential disengagement of the first and second sections of the clutch. This mechanism comprises an operating lever 20 which is pivoted adjacent its one end at 21 and which is provided at its other end with an adjustable pad 22 for engagement with a release ring when such release ring is moved axially. At its end beyond its pivot 21, the lever is pivotally connected to a link 23, which link is itself pivotally connected at 24 to the presser plate 13. A push rod 25 is disposed between the presser plates 13 and 17, and there is provided adjustable means indicated generally at 26 for the setting of a predetermined clear ance between the presser plate 13 and push rod 25. Thus, when the release lever 20 is operated the presser plate 13 is pulled away from its clamping engagement with the driven plate 14, and subsequently when the clear ance between the presser plate 13 and push rod 25 pre-set by the adjustment means 26 has been taken up further movement of the lever 20 will release the presser plate 17 from engagement with the driven plate assembly 18a, 18b. It will of course be appreciated that there will be provided a number, typically 3, of assemblies of release levers 20 and associated components disposed angularly about the rotational axis of the clutch.

On one side of the clutch, i.e. the input side, nearest the prime mover, the driving plate 10 (flywheel) is provided with an undercut annular groove 30 with an inwardly directed annular opening and defined in part by an annular plate 30a, providing an annular reservoir into which fluid such as oil is introduced from a suitable circulation system 30b and more fully described in our patent Specification 1557169 and copending application (Serial No. 1582128). No. 28386/76 A plurality of apertures 31, spaced angularly about the axis of the clutch, extend axially through the driving plate 10 at similar distances in directions radially thereof and open into a region of the clutch located radially inwardly of the frictionally engaging parts of the first and second sections thereof.

A generally annular dished element 32 is secured to the inside face of the plate 10, and provides means for directing of the fluid emerging through the apertures 31 to the two section of the clutch as required.

The element 32 is formed, in its end face which contacts the plate 10, with a number of holes which are in register with some of the apertures 31 in the plate. This arrangement constitutes one set of fluid directing means, in that fluid passing through these apertures leaves the element 32 at its open end 33, and can pass in open space through apertures 35 formed in the inner portion of the driven plate 14 to reach the torque transmitting parts 16, 17, 18, of the second section of the clutch. (See Figure 1.) At positions corresponding to others of the apertures 31 in the plate 10, the element 32 is not apertured but is displaced inwardly as at 34. This arrangement constitutes a second set of fluid directing means in that fluid passing through these apertures 31 is directed outwardly through open space to the region of the torque transmitting parts 10, 13, 14, of the first section of the clutch.

(See Figure 2.) By this construction in which both parts of the divided fluid flow pass through open space, appropriate fluid distribution to both sections of the clutch is achieved, irrespective of whether one section is disengaged. With one or more closed conduits in place of open space, back pressures in the conduit which vary with operation of the clutch could vary the distribution of the fluid.

It will be appreciated that various modifications can be made to the specific construction described above. For example, the ele ment 32 could be formed integrally with the driving plate 10 (flywheel) rather than b ing a separate component. or the particular form of the element could be arranged to discharge fluid at a different position from the remainder of the apertures, to achieve the required distribution of fluid.

WHAT WE CLAIM IS:- 1. A dual friction clutch including two sections for respectively coupling a common input shaft to two output shafts and having an annular groove located radially inwardly of torque-transmitting components of the two sections, the groove having an inwardly directed annular opening into which, in use, fluid for distribution to the two sections is introduced, such distribution being effected by two sets of fluid directing means arranged to discharge fluid from the groove under the influence of centrifugal force into two separated open spaces in the interior of the clutch such that fluid from one set is directed through one open space towards one section and fluid from the other set is directed through the other open space towards the other section of the clutch.

2. A clutch according to claim 1 wherein each section comprises a driving member, an axially movable presser member, and a driven member adapted to be driven by being clamped between the driving member and the presser member, the driving member for the first section incorporating the annular groove on the opposite side thereof from the driven member and being provided with axially extending passage means through which fluid is introduced into the inner region of the clutch, the fluid directing means co-operating with said passage means to provide for discharge of fluid to two axially spaced open spaces, from which fluid can flow to the two sections of the clutch.

3. A clutch according to claim 2 wherein the passage means is provided by a plurality of angularly spaced apertures extending through the driving member of the first section, the fluid directing means comprising a member co-operating with some of the apertures to direct fluid emerging therefrom to one open space, and with others of the apertures to direct fluid emerging therefrom to the other open space.

4. A clutch according to claim 3 wherein the apertures extend through said driving member at similar distances in directions radially of the flywheel.

5. A clutch according to one of claims 3 and 4 wherein the fluid directing means is provided by a dished element into which fluid from some of the apertures flows and from which fluid is directed to one of the sections of the clutch.

6. A clutch according to claim 5 wherein said dished element is so formed as to direct fluid flowing from others of the apertures, to the other section of the clutch.

7. A clutch according to claim 2 wherein the fluid directing means is formed integrally with, or is connected to, the driving member of the first section.

8. A friction clutch of the dual clutch type, constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. ment 32 could be formed integrally with the driving plate 10 (flywheel) rather than b ing a separate component. or the particular form of the element could be arranged to discharge fluid at a different position from the remainder of the apertures, to achieve the required distribution of fluid. WHAT WE CLAIM IS:-

1. A dual friction clutch including two sections for respectively coupling a common input shaft to two output shafts and having an annular groove located radially inwardly of torque-transmitting components of the two sections, the groove having an inwardly directed annular opening into which, in use, fluid for distribution to the two sections is introduced, such distribution being effected by two sets of fluid directing means arranged to discharge fluid from the groove under the influence of centrifugal force into two separated open spaces in the interior of the clutch such that fluid from one set is directed through one open space towards one section and fluid from the other set is directed through the other open space towards the other section of the clutch.

2. A clutch according to claim 1 wherein each section comprises a driving member, an axially movable presser member, and a driven member adapted to be driven by being clamped between the driving member and the presser member, the driving member for the first section incorporating the annular groove on the opposite side thereof from the driven member and being provided with axially extending passage means through which fluid is introduced into the inner region of the clutch, the fluid directing means co-operating with said passage means to provide for discharge of fluid to two axially spaced open spaces, from which fluid can flow to the two sections of the clutch.

3. A clutch according to claim 2 wherein the passage means is provided by a plurality of angularly spaced apertures extending through the driving member of the first section, the fluid directing means comprising a member co-operating with some of the apertures to direct fluid emerging therefrom to one open space, and with others of the apertures to direct fluid emerging therefrom to the other open space.

4. A clutch according to claim 3 wherein the apertures extend through said driving member at similar distances in directions radially of the flywheel.

5. A clutch according to one of claims 3 and 4 wherein the fluid directing means is provided by a dished element into which fluid from some of the apertures flows and from which fluid is directed to one of the sections of the clutch.

6. A clutch according to claim 5 wherein said dished element is so formed as to direct fluid flowing from others of the apertures, to the other section of the clutch.

7. A clutch according to claim 2 wherein the fluid directing means is formed integrally with, or is connected to, the driving member of the first section.

8. A friction clutch of the dual clutch type, constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.