GB1582128A - Clutches - Google Patents

Description

(54) IMPROVEMENTS RELATING TO CLUTCHES (71) We, GKN TRANSMISSIONS LIMITED, 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 partcularly of the kind in which frictionally engaging torque transmitting elements of the clutch operate in the presence of a liquid such as oil, for example for the purpose of assisting in dissipation of frictionally generated heat from the elements, there being provided means for establishing a circulation of the liquid when the clutch is in use, the liquid being introduced into a central region of the clutch and flowing generally radially outwardly therefrom. Such a clutch, commonly termed a wet clutch, will hereafter be referred to as a clutch of the kind specified.

One form of liquid circulation system which has been proposed hitherto involves the provision, in the driving element of the clutch, of a radially undercut annular groove into which the liquid is introduced by a pipe leading from a collection chamber disposed in the upper region of the clutch housing (which chamber collects liquid flung up by the clutch when rotating) and from which the liquid flows to the torque-transmitting elements of the clutch. The formation of the groove as radially undercut ensures that liquid tends to be retained therein by centrifugal force and does not escape other than by way of the torque-transmitting elements of the clutch. However, the introduction of liquid into the groove by a single pipe can lead to irregular flow of liquid through the torque-transmitting elements, and imposes a severe limitation on the rate of delivery of liquid to the clutch.

It is an object of the present invention to provide a clutch of the kind specified in which these disadvantags are overcome or reduced.

According to the present invention, we provide a clutch of the kind specified wherein a part of the clutch which, in use, rotates, is provided with an annular liquid-receiving formation, and the means for establishing circulation of liquid includes collector means arranged to collect liquid thrown up by rotation of the clutch and conduit means extending downward from the collector means so that liquid flows down the conduit under gravity and having an annular exit concentric with and inwardly of the liquid receiving formation from which liquid can pass into the liquid-receiving formation.

The feeding of liquid from conduit means into the liquid-receiving formation by way of the annular exit facilitates the achievement of a more even distribution of the liquid circumferentially of the clutch, and in addition to this permits a relatively greater flow of liquid than has hitherto in general been possible.

The annular portion of the conduit means and its exit may be defined at least in part by a fixed annular member of the clutch, or at least in part by a component which in use rotates. Preferably however the annular portion and its exit are defined between both such a fixed annular member and such a component which in use rotates, e.g. a shaft on which the clutch is mounted.

This invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 is a section through part of a clutch embodying the invention, Figure 2 is an axial view of part of the clutch of Figure 1, and Figure 3 is a side elevation of the part shown in Figure 2.

Referring firstly to Figure 1, the illustrated clutch comprises a driving element 10 which is connected to an output shaft 11 of a prime mover, e.g. an internal combustion engine, by bolts as 12. The driving element 10 is provided at its periphery with a starter ring gear 9, and constitutes a flywheel for the prime mover.

Axially movable relative to the driving element 10, but rotationally fast therewith, there is provided a pressure element in the form of a plate 13. Between the driving element 10 and pressure plate 13 there is disposed a driven element 14 having annular friction surfaces 15, the element 14 being riveted to a member 16 which is itself secured to an internally splined hub 17 for connection to an output shaft, not shown.

The pressure plate 13 is spring biased to the left, with reference to the drawing, by spring means not shown, for bringing the surfaces 15 of the driven element 14 into torque transmitting frictional engagement with the opposed faces of the driving element 10 and pressure plate 13, a release mechanism (not shown) being provided for controlling such movement to engage or discharge the clutch as required.

The face of the driving element 10 nearest the prime mover is provided with an annular member 18 which, in combination with a groove formation 19, defines a radially undercut annular groove 20. A plurality of circumferentially distributed apertures 21 extend through the element 10, and communicate with a distribution member 22 which provides for appropriate distribution of liquid passing through apertures 21 to appropriate parts of the clutch. Thus, liquid introduced into the groove 20 tends to remain held therein due to centrifugal force arising from rotation of the clutch in use, and escapes by way of apertures 21 to be distributed through the torque transmitting components of the clutch such as surfaces 15.

For introducing liquid into the groove 20 so as to ensure a circulation of such liquid when the clutch is in operation, there is provided an arrangement which includes an assembly most clearly shown in Figures 2 and 3. This assembly includes a collector 25 made of sheet metal and of somewhat pyramidal form having an open mouth 26.

The mouth 26 is so positioned relative to the rotating parts of the clutch, and the housing in which the clutch is disposed, as to receive liquid thrown around by one at least of the rotating parts and to convert some at least of the kinetic energy of such thrown liquid into a pressure head to cause the ]iquid to flow from the collector through a rectangular section sheet metal passage 27.

The walls of the passage 27 are joined by welding at a line 28 to an annular member 29 which is secured, by bolts passing through apertures as 30, to a stationary wall 31, which may for example be the end wall of the crank case of the internal combustion engine. Between the member 29 and wall 31 there is provided a seal carrier 32 which supports two guide seals 33 arranged in back-to-back relation and engaging the shaft 11.

The member 29 is of stepped shape towards its inner periphery, so as to define, in combination with the seal carrier 32, seals 33, and shaft 11, an annular passageway 34. The innermost axially extending portion 35 of the member 29 terminates at a position to define in combination with the shaft 11 an annular exit which lies within the groove 20 so that liquid issuing therefrom enters the groove.

In use, liquid trapped by the collector 25 passes through conduit means, provided collectively by the passage 27 and the annular passage 34. Because the end part of the passage 34 is partly defined by a member, i.e. the shaft 11, which is rotating, the fluid acquires a certain degree of angular motion in this portion of the passage, and thus enters the groove 20 over an annular region rather than from one point alone.

The liquid then passes through the apertures 21 to circulate through the torque transmitting part of the clutch to again be thrown into the collector.

Reference is hereby drawn to our Patent Specification No. 1,557,169, to which reference should be made for further details of the construction and operation of the above described preferred embodiment of this invention. Attention is directed to claims 1 and 10 of our said Patent Specification No.

1,557,169.

WHAT WE CLAIM IS: 1. A clutch of the kind specified wherein a part of the clutch which, in use, rotates is provided with an annular liquid-receiving formation, and the means for establishing circulation of liquid includes collector means arranged to collect liquid thrown up by rotation of the clutch, and conduit means extending downward from the collector means so that liquid flows down the conduit under gravity and having an annular exit concentric with and inwardly of the liquidreceiving formation through which liquid may flow into the liquid-receiving formation.

2. A clutch according to claim 1 wherein the annular portion of the conduit means and its exit are defined at least in part by a fixed annular member of the clutch.

3. A clutch according to claim 1 wherein the annular portion of the conduit means and its exit are defined at least in part by a component of the clutch which in use rotates.

4. A clutch according to claim 1 wherein the annular portion of the conduit means and its exit are defined between a fixed annular member and a component of the clutch which in use rotates.

5. A clutch according to any one of the preceding claims wherein the annular liquid receiving formation is provided by, and on one side of a flywheel of the clutch, there being provided in the flywheel apertures at

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

Claims (1)

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

   element 10, but rotationally fast therewith, there is provided a pressure element in the form of a plate 13. Between the driving element 10 and pressure plate 13 there is disposed a driven element 14 having annular friction surfaces 15, the element 14 being riveted to a member 16 which is itself secured to an internally splined hub 17 for connection to an output shaft, not shown.

   The pressure plate 13 is spring biased to the left, with reference to the drawing, by spring means not shown, for bringing the surfaces 15 of the driven element 14 into torque transmitting frictional engagement with the opposed faces of the driving element 10 and pressure plate 13, a release mechanism (not shown) being provided for controlling such movement to engage or discharge the clutch as required.

   The face of the driving element 10 nearest the prime mover is provided with an annular member 18 which, in combination with a groove formation 19, defines a radially undercut annular groove 20. A plurality of circumferentially distributed apertures 21 extend through the element 10, and communicate with a distribution member 22 which provides for appropriate distribution of liquid passing through apertures 21 to appropriate parts of the clutch. Thus, liquid introduced into the groove 20 tends to remain held therein due to centrifugal force arising from rotation of the clutch in use, and escapes by way of apertures 21 to be distributed through the torque transmitting components of the clutch such as surfaces 15.

   For introducing liquid into the groove 20 so as to ensure a circulation of such liquid when the clutch is in operation, there is provided an arrangement which includes an assembly most clearly shown in Figures 2 and 3. This assembly includes a collector 25 made of sheet metal and of somewhat pyramidal form having an open mouth 26.

   The mouth 26 is so positioned relative to the rotating parts of the clutch, and the housing in which the clutch is disposed, as to receive liquid thrown around by one at least of the rotating parts and to convert some at least of the kinetic energy of such thrown liquid into a pressure head to cause the ]iquid to flow from the collector through a rectangular section sheet metal passage 27.

   The walls of the passage 27 are joined by welding at a line 28 to an annular member 29 which is secured, by bolts passing through apertures as 30, to a stationary wall 31, which may for example be the end wall of the crank case of the internal combustion engine. Between the member 29 and wall 31 there is provided a seal carrier 32 which supports two guide seals 33 arranged in back-to-back relation and engaging the shaft 11.

   The member 29 is of stepped shape towards its inner periphery, so as to define, in combination with the seal carrier 32, seals 33, and shaft 11, an annular passageway 34. The innermost axially extending portion 35 of the member 29 terminates at a position to define in combination with the shaft 11 an annular exit which lies within the groove 20 so that liquid issuing therefrom enters the groove.

   In use, liquid trapped by the collector 25 passes through conduit means, provided collectively by the passage 27 and the annular passage 34. Because the end part of the passage 34 is partly defined by a member, i.e. the shaft 11, which is rotating, the fluid acquires a certain degree of angular motion in this portion of the passage, and thus enters the groove 20 over an annular region rather than from one point alone.

   The liquid then passes through the apertures 21 to circulate through the torque transmitting part of the clutch to again be thrown into the collector.

   Reference is hereby drawn to our Patent Specification No. 1,557,169, to which reference should be made for further details of the construction and operation of the above described preferred embodiment of this invention. Attention is directed to claims 1 and 10 of our said Patent Specification No.

   1,557,169.

   WHAT WE CLAIM IS:

   1. A clutch of the kind specified wherein a part of the clutch which, in use, rotates is provided with an annular liquid-receiving formation, and the means for establishing circulation of liquid includes collector means arranged to collect liquid thrown up by rotation of the clutch, and conduit means extending downward from the collector means so that liquid flows down the conduit under gravity and having an annular exit concentric with and inwardly of the liquidreceiving formation through which liquid may flow into the liquid-receiving formation.

   2. A clutch according to claim 1 wherein the annular portion of the conduit means and its exit are defined at least in part by a fixed annular member of the clutch.

   3. A clutch according to claim 1 wherein the annular portion of the conduit means and its exit are defined at least in part by a component of the clutch which in use rotates.

   4. A clutch according to claim 1 wherein the annular portion of the conduit means and its exit are defined between a fixed annular member and a component of the clutch which in use rotates.

   5. A clutch according to any one of the preceding claims wherein the annular liquid receiving formation is provided by, and on one side of a flywheel of the clutch, there being provided in the flywheel apertures at

   a plurality of angularly spaced positions by which fluid may flow from said receiving formation through the flywheel to the other side thereof.

   7. A friction clutch constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.