GB2150653A

GB2150653A - Friction clutch with two-part flywheel

Info

Publication number: GB2150653A
Application number: GB08428835A
Authority: GB
Inventors: Oswald Friedmann
Original assignee: LuK Lamellen und Kupplungsbau GmbH
Current assignee: LuK Lamellen und Kupplungsbau GmbH
Priority date: 1983-12-02
Filing date: 1984-11-15
Publication date: 1985-07-03
Also published as: IT8423605A1; DE3447925C2; DE3447925A1; IT8423605A0; AT395343B; GB8428835D0; ES8701322A1; IT1177219B; ATA339585A; ES546922A0; GB2150653B; BR8406107A

Abstract

A torque transmitting arrangement has at least two coaxially disposed flywheel masses (3, 4) which are limitedly rotatable relative to each other against the action of a damping means (13). The flywheel mass (3) can be connected to an internal combustion engine shaft (5) and the other can be connected by way of a friction clutch to the input member (10) of a transmission. The flywheel masses (4, 3) are limitedly axially displaceable relative to each other in dependence on actuation of the friction clutch and can thereby vary the action of the damping means (13). <IMAGE>

Description

SPECIFICATION Torque transmitting arrangement The invention relates to a torque transmitting arrangement including a means fgr absorbing or compensating for rotary shocks, in particular fluctuations in torgue of an internal combustion engine, having at least two coaxially disposed flywheel masses which are limited rotatable relative to each other against the action of a damping means, of which the one, first flywheel mass can be connected to the internal combustion engine and the other second flywheel mass can be connected by way of a friction clutch to the input member of a transmission, and wherein the friction clutch is actuable by way of a release system.

A torque transmitting arrangement of that kind is disclosed for example in DE-OS No 28 26 274. In that arrangement, the flywheel mass which can be connected to the input member of a transmission is rotatably mounted, with the interposition of a flanged sleeve, on an axial extension portion of the flywheel mass which is connected to the crankshaft of an internal combustion engine.

In that design, the arrangement of the flanged sleeve is such that the radial flange of the sleeve carries the force required for release of the friction clutch which is provided on the flywheel mass which can be connected to the input member of a transmission, the radial flange transmitting the force applied thereto, to the flywheel mass which is connected to the internal combustion engine. By virtue of that design configuration, when the friction clutch is actuated, the radial flange of the flanged sleeve is gripped between the two flywheel masses with a high force, thereby producing a very high frictional moment between the two flywheel masses. However, such a high level of frictional moment is a disadvantage for many situations for use as it detrimentally affects the function of the damper means which is provided between the two flywheel masses.Such impairment of the function of the damper means has a particularly adverse effect during release and engagement of the friction clutch, as the clutch plate is not released by the friction clutch over a large part of the actuating travel which is covered by the release system or the radially inward tips of the tongue portions of the diaphragm spring, that is to say, the internal combustion engine and the input member of the transmission are still connected together.

The fact that the mode of operation of the damper means is detrimentally affected, precisely over the above-indicated range of clutch actuation travel, mean that oscillations of substantial amplitudes can occur between the internal combustion engine and the transmission, and results in an increased level of load on the drive shaft and vibration and noise which adversely affect the degree of comfort.

The present invention was based on the problem of providing a torque transmitting arrangement which is improved in fuction in comparison with the previously disclosed arrangements of the kind set forth in the opening part of this specification, and which ensures an increased range of use, while also permitting better and easier adaptation to the respective situation of use and also being capable of being manufactured in a particularly simple and inexpensive fashion.

According to the invention, in a torgue transmitting arrangement of the kind set forth in the opening part of this specification, that is achieved in that the flywheel masses are limitedly axially displaceabcle relative to each other in dependence on actuation of the friction clutch.

Such axial displaceability as between the two flywheel masses can be utilised in a particularly advantageous fashion for varying the damping characteristic of a friction means which is operatively disposed between the two flywheel masses. In that connection, it may be particularly advantageous if the axial displaceability of the two flywheel masses relative to each other takes place against the action of a force storage means which applies to the flywheel mass which can be connected to the input member of a transmission, a force which is in opposition to the release force for the friction clutch provided on the flywheel mass which can be connected to the input member of the transmission.

For some situations of use, it may be advantageous for the flywheel masses to be of a plate-like configuration and to be axially limitedly movable towards each other in dependence on release of the friction clutch and axially limitedly movable away from each other again upon clutch engagement. However, for other situations of use it may be desirable for the torque transmitting arrangement to be such that the flywheel masses are axially limitedly movable away from each other in dependence on release of the friction clutch and axially limitedly movable towards each other again upon clutch engagement.

Particularly in the case of a torque transmitting means wherein the flywheel masses are axially limitedly movable towards each other in dependence on release of the friction clutch, it may be appropriate for the friction clutch which is fixed on the second flywheel mass which can be connected to the input member of a transmission to be what is referred to as a press-type clutch. In the case of a torque transmitting arrangement wherein the flywheel masses are axially limitedly movable away from each other in dependence on release of the friction clutch, it may be desirable for the friction clutch which is fixed on the second flywheel mass to be what is referred to as a pull-type clutch, in which re spect it may then also be advantageous for the two flywheel masses to be braced towards each other by way of at least on force storage means.In a torque transmitting arrangement wherein a press-type clutch is fixed on the second flywheel mass on the other hand, it may be desirable for the two flywheel masses to be urged away from each other by at least one force storage means. The force storage means may be formed, in a particularly advantageous manner, by a diaphragm spring.

In accordance with a further feature of the invention, it may be desirable for the axial displacement of the two flywheel masses relative to each other to be restricted by abutments. It may also be advantageous if the flywheel masses are in or can be brought into frictional or sliding engagement with each other by way of at least two friction or sliding surfaces, wherein the damping action of said connection can be variable in dependence on actuation of the friction clutch. In that respect, the variation in the damping action of the friction or sliding connection may take place in dependence on, that is to say, as a function of, the axial movement of the two flywheel masses relative to each other.It may be advantageous in that arrangement if, upon release of the friction clutch, the damping action of the friction or sliding connection decreases, while depending on the situation of use it may be desirable for the damping action to be either only partially or however completely removed.

In accordance with a further feature of the invention, it may be advantageous for the friction or sliding connection to be formed by at least one friction or sliding lining which is provided between the two flywheel masses and which may be provided between mutually facing faces of the two flywheel masses which are of a disc-like configuration. In that connection, it may be advantageous for the friction or sliding lining to be disposed in an annular arrangement and possibly, when the friction clutch is not actuated, to be gripped between the two flywheel masses by the force storage means which urge the two flywheel masses towards or away from each other.Advantageously, the construction of the torque transmitting arrangement in that case may be such that, upon disengagement of the friction clutch, the clamping effect on the friction ring and thus also the damping action thereof are eliminated. For some situations of use however it may also be advantageous for the clamping action on the friction ring to be only reduced upon release of the friction clutch, by virtue of the axial displacement between the two flywheel masses which takes place when that occurs, so that even when the friction clutch is in the disengaged condition, there is still a damping effect in respect of the friction ring, although at a reduced level.

It may also be particularly advantageous for the two flywheel masses to be mounted rotatably relative to each other by way of a rolling bearing, wherein one of the bearing races may advantageously be axially fixed to the second flywheel mass and the other mav be axially displaceable on an axial extension portion provided on the first flywheel mass. In that arrangement, it may be desirable for the force storage means which urges the flywheel masses towards or away from each other to engage the axially displaceable race of the rolling bearing and to secure same against rotary movement relative to the flywheel mass which carries that bearing race.

It may also be advantageous for the damping means to comprise periphery operative force storage means and/or friction or sliding means which are operative in addition to the friction or sliding connection which is provided between the two flywheel masses and which is variable in dependence on actuation of the friction clutch. That ensures that there is a wide range of possible variations for the purposes of producting quite definite damping characteristics, whereby the arrangement can also be satisfactorily adapted to the respective situation of use.

The invention will now be described in greater detail with reference to Figs. 1 and 2.

In the drawings: Figure 1 is a cross-sectional view of a torque transmitting arrangement according to the invention, and Figure 2 is another embodiment of a torque transmitting arrangement according to the invention.

The torque transmitting arrangement 1 shown in Fig. 1, for absorbing or compensating for rotary shocks or pulses, comprises a flywheel 2 which is divided into two flywheel masses 3 and 4. The flywheel mass 1 is fixed on a crankshaft 5 of an internal combustion engine (not shown) by way of screws 6. A friction clutch 7 which is of the kind referred to as a press-type clutch is secured to the flywheel mass 4 by way of screws (not shown). Provided between the pressure plate 8 of the friction clutch 7 and the flywheel mass 4 is a clutch disc 9 which is carried on the input shaft 10 of a transmission (not shown). The pressure plate 8 of the friction clutch 7 is urged towards the flywheel mass 4 by a diaphragm spring 1 2 which is pivotally mounted on the clutch cover 11. By actuation of the friction clutch 7, the flywheel mass 4 and thus also the flywheel 2 can be coupled to and uncoupled from the input shaft 10 of the transmission, by way of the clutch disc 9.

Disposed between the two flywheel masses 3 and 4 is a damping means 1 3 which acts in opposition to relative rotary movement as between the two flywheel masses.

The two flywheel masses 3 and 4 are mounted rotatably relative to each other by way of a bearing arrangement 14. The bear ing arrangement 14 comprises a rolling bearing 15, the outer race 15a of which is nonrotatably carried in a receiving bore 1 6 in the flywheel mass 4 while the inner bearing race 15b is non-rotatably carried on the shoulder 1 7 of a projection 18, which faces away from the crankshaft 5, of the flywheel mass 3.The rolling bearing 1 5 is held on the projection 1 8 on the flywheel mass 3 by means of a shaped sheet metal member 1 9. The member 1 9 is connected to the flywheel mass 3 by way of a rivet connection 20 and engages axially behind the inner bearing race 15b, with a radially extending outer edge portion 19a.

The damping means 1 3 has force storage means in the form of coil springs 21 of which only one is shown in the drawing, and friction means in the form of a friction ring 22 for damping the springs 21.

The input member of the damping means 1 3 is formed by two discs 23 and 24 which are non-rotatably connected together at an axial spacing by way of spacer pins 25. At its periphery, the disc 24 has radially extending arms 24b which bear against the face 26 of an annular axial projection 27 on the flywheel mass 3 and are secured thereto by means of a rivet connection 28. Disposed between the two discs 23 and 24 is a flange-like component 29 which forms the output member of the damping means 1 3. At its outer periphery, the output member 29 has radially extending arm portions 30 which are axially displaced relative to the radial regions 31 of the output member 29, which extend between the two discs 23 and 24.The radial arm portions 30 bear against the face 32 of the flywheel mass 4 and are there secured to the flywheel mass 4 by way of a rivet connection 33. The radial arm portions 30 and the radial arms 24b are angularly displaced relative to each other, as considered in the peripheral direction of the flywheel 2.

Provided in the discs 23 and 24 and in the output member 29 are openings 23a, 24a and 29a in which the coil springs 21 of the damping means 1 3 are accommodated. In that connection, the openings 23a, 24a and 29a as well as the coil springs 21 disposed therein are so arranged and dimensioned, as considered in the peripheral direction of the damping means 13, as to provide a multistage damping characteristic. The output member 29 also has arcuately curved openings 29b through which the spacer pins 25 project. The relative rotary movement as between the two flywheel masses 3 and 4 is limited to the spacer pins 25 abutting against the end regions of the arcuately curved openings 29b.

The friction ring 22 which provides for friction damping is gripped between the disc 24 and the radial portions 31 of the output member 29 when the friction clutch 7 is not in the released condition. The gripping action is produced by a force storage means in the form of a diaphragm spring 34 which bears against the radially extending regions of the shoulder 1 7 and which urges the inner bearing race 15b in a direction away from the crankshaft 5, whereby the flywheel mass 4 and the components secured thereon are urged away from the flywheel mass 3.

In order to ensure the necessary axial displaceability of the flywheel mass 4 relative to the flywheel mass 3, the inner bearing race 15b is axially displaceably but non-rotatably carried on the projection portion 1 8 or the sheet metal member 19. For the purposes of securing the bearing race 15b against rotational movement, the member 1 9 has a radially projecting projection 1 9b which engages into a longitudinal groove 1 sic in the bearing race 15b. In order to ensure that a friction ring 22 which is partially worn is gripped between the output member 29 and the disc 24, an axial re-adjustment clearance is provided between the bearing race 15b and the radially extending outer edge portions 19a.

The diaphragm spring 34 is fitted in such a manner that, when the biassing force thereof is overcome, it can be pivoted by a predetermined amount X. In the embodiment illustrated in Fig. 1, that amount X represents the axial distance over which the flywheel mass 4 and thus also the components secured thereon can be axially displaced towards the flywheel mass 3 upon release of the friction clutch 7. Depending on the situation of use, the travel X may be of the order of magnitude of 0.1 to 2 mm.

The friction moment generated by the friction ring 22 may be suitably varied by altering the characteristic of the diaphragm spring 34 or 36 respectively.

Starting from the position illustrated in Fig.

1, the mode of operation of the torque transmitting means 1 is as follows: When the friction clutch 7 is in the engaged condition, the maximum friction moment generated by the friction ring 22 takes effect upon relative rotation between the two flywheel masses 3 and 4. As soon as the clutch release member 35 acts on the radially inward tips 1 2a of the tongue portions of the diaphragm spring, in order to release the friction clutch 7, the biassing force of the diaphragm spring 34 is gradually compensated, with increasing clutch release force, so that the friction moment generated by the friction ring 22 decreases with increasing clutch release force. As soon as the applied clutch release force overcomes the biassing force of the diaghragm spring 34, the spring 34 is pivoted and the flywheel mass 4 is displaced towards the flywheel mass 3 by the distance X.That displacement causes the friction ring 22 which is secured to the output member 29 to lift away from the disc 24 so that the friction ring 22 no longer generates any friction damping effect.

The bearing 15 is also axially displaced with the flywheel mass 4. The bearing 1 5 must carry the force required for release of the friction clutch 7.

For the purposes of engagement of the friction clutch 7, the axial force acting on the clutch release member 35 is gradually reduced, whereby firstly the diaphragm spring 1 2 which is pivotally mounted to the cover 11 pivots, by virtue of its spring action, and thereby displaces the pressure plate 8 towards the flywheel mass 4 so that the clutch disc 9 is gradually clamped between the flywheel mass 4 and the pressure plate 8. As soon as the force acting on the tips 1 2a of the tongue portions of the diaphragm spring becomes less than the force produced by the stressed diaphragm spring 34, the bearing 1 5 and thus also the flywheel mass 4 and the components secured thereon are moved away from the flywheel mass 3 by the distance X.By virtue of that movement, the friction ring 22 comes back into a position of bearing against the disc 24 and, as a result of the residual biassing force of the diaphragm spring 34, again generates a friction moment between the flywheel masses 3 and 4.

In accordance with another alternative embodiment, additional friction or sliding means may be provided between the flywheel masses 3 and 4, such means ensuring frictional damping between the two flywheel masses 3 and 4 when the clutch 7 is in the release condition. Such a means may be formed, for example as shown in broken lines in Fig. 1, by a diaphragm spring 36 which is arranged opposite the friction ring 22 on the other side of the flange-like component 29. The diaphragm spring 36 is braced between the flange-like component 29 and the disc 23 and is secured against rotational movement relative to the disc 23 and the flywheel mass 3 so that, upon relative rotational movement between the two flywheel masses 3 and 4 the diaphragm spring 36 rubs with its radially inward regions against the component 29.In contrast to the frictional moment produced by the friction ring 22, the frictional moment produced by the diaphragm spring 36 is maintained even when the friction clutch 7 is in a release position. Depending on the design of the diaphragm spring 36, the frictional moment produced by the diaphragm spring 36 may vary upon engagement and release of the friction clutch, by virtue of the displacement as between the two flywheel masses 3 and 4.

As the diaphragm spring 36 also provides for biassing of the two flywheel masses 3 and 4, the diaphragm spring 34 may optionally be omitted.

The torque transmitting arrangement illustrated in Fig. 2 differs from that shown in Fig.

1, essentially in that a friction clutch 107 which is of the kind referred to as a pull-type clutch is fixed on the flywheel mass 4, the friction ring 1 22 is arranged on the other side of the output member 29, and the diaphragm spring 1 34 is disposed between the inner bearing race 15b and the radially extending outer edge portions 1 9a of the shaped sheet metal member 1 9.

The stressing of the diaphragm spring 1 34 causes the bearing 15 and thus also the flywheel mass 4 and the components secured thereto to be urged towards the flywheel mass 3. Consequently, the friction ring 1 22 which is fixed on the output member 29 is gripped between the output member 29 and the disc 23. There is an axial clearance between the radially extending portions of the shoulder 1 7 and the inner bearing race 15b in order to permit re-adjustment, that is to say, axial displacement of the flywheel mass 4 towards the flywheel mass 3, in the event of wear on the friction ring 1 22.

The diaphragm spring 1 34 is once again fitted in such a manner that, when its biassing force is overcome, it can be pivoted or compressed by a predetermined amount X so that the friction ring 1 22 can lift away from the disc 23 when the friction clutch is released.

The embodiment illustrated in Fig. 2 may also include an additional diaphragm spring 1 36 which produces a frictional moment, even when the friction clutch is in a release position. When such a diaphragm spring 1 36 is provided, the diaphragm spring 1 34 may possibly be omitted.

Starting from the position shown in Fig. 2, the mode of operation of the torque transmitting arrangement is as follows: When the friction clutch 107 is in the engaged condition, the maximum friction moment which is produced by the friction ring takes effect upon relative rotary movement as between the two flywheel masses 3 and 4. As soon as the inner tips 11 2a of the tongue portions of the diaphragm spring are urged away from the flywheel mass 3, the biassing force of the diaphragm spring 1 34 is gradually compensated, the increasing clutch release force, so that the frictional moment produced by the friction ring 1 22 decreases.

As soon as the clutch release force applied to the tips 11 2 of the tongue portions of the diaphragm spring exceeds the biassing force of the diaphragm spring 134, the diaphragm spring 1 34 is pivoted or compressed and the flywheel mass 4 is moved away from the flywheel mass 3 by the distance X. That displacement causes the friction ring 1 22 which is secured to the output member 29 to lift away from the friction disc, so that there is no longer any friction damping effect.

In the operation of engaging the friction clutch 107, as soon as the force applied to the tips 11 2 of the tongue portions of the diaphragm spring falls below the force of the stressed diaphragm spring 134, the flywheel mass 3 and thus also the output member 29 with the friction ring 1 22 secured thereto is moved towards the flywheel mass 3 whereby the friction ring 1 22 comes to bear again against the disc 23 and can produce a frictional moment.

It will be appreciated that the nature of the variation in friction during the clutch release and clutch engagement operations can be influenced by suitable matching as between the diaphragm springs 34, 36 and 134, 1 36 respectively, which permit the relative axial displaceability of the two flywheel masses 3 and 4, and the variation in the force for release of the friction clutch 7. For some situations of use it may even be advantageous for the diaphragm spring 34 or 1 34 to have a somewhat higher biassing force than the maximum actuating force required for actuating the friction clutch 7 so that, during actuation of the friction clutch 7, the frictional moment produced by the friction rings 22 or 1 22 is admittedly reduced but is not entirely eliminated.

Claims

1. A torque transmitting arrangement including a means for absorbing or compensating for rotary shocks, in particular fluctuations in torque of an internal combustion engine, having at least two coaxially disposed flywheel masses which are limitedly rotatable relative to each other against the action of a damping means, of which the one, first flywheel mass can be connected to the internal combustion engine and the other, second flywheel mass can be connected by way of a friction clutch to the input member of a transmission, wherein the friction clutch is actuable by way of a release system, characterised in that the flywheel masses (3, 4) are limitedly axially displaceable relative to each other in dependence on actuation of the friction clutch (7, 107).

2. A torque transmitting arrangement according to claim 1 characterised in that the flywheel masses (3, 4) are of a plate-like configuration and are axially limitedly displaceable towards each other in dependence on release of the friction clutch (7) and are axially limitedly movable away from each other again upon clutch engagement.

3. A torque transmitting arrangement according to claim 1 characterised in that the flywheel masses (3, 4) are axially limitedly movable away from each other in dependence on release of the friction clutch (107) and axially limitedly movable towards each other again upon clutch engagement.

4. A torque transmitting arrangement according to one of claims 1 or 2 characterised in that a so-called press-type clutch (7) is secured to the second flywheel mass (4).

5. A torque transmitting arrangement according to one of claims 1 or 3 characterised in that a so-called pull-type clutch (107) is secured on the second flywheel mass (4).

6. A torque transmitting arrangement according to one of claims 1, 3 or 5 characterised in that the two flywheel masses (3, 4) are braced towards each other by way of at least one force storage means (134, 136).

7. A torque transmitting arrangement according to one of claims 1, 2 or 4 characterised in that the two flywheel masses (3, 4) are urged away from each other by at least one force storage means (34, 36).

8. A torque transmitting arrangement according to one of claims 1 to 7 characterised in that the force storage means (34, 36; 134, 136) is formed by a diaphragm spring.

9. A torque transmitting arrangement according to one of claims 1 to 8 characterised in that the axial displacement (X) of the two flywheel masses (3, 4) relative to each other is restricted by abutments (1 7, 1 9a).

10. A torque transmitting arrangement according to one of claims 1 to 9 characterised in that the flywheel masses (3. 4) are in or can be brought into frictional or sliding engagement with each other by way of at least two friction or sliding surfaces, wherein the damping action of said connection is variable in dependence on actuation of the friction clutch (7, 107).

11. A torque transmitting arrangement to claim 10 characterised in that the damping action of the friction or sliding connection varies in dependence on the axial displacement (X) of the two flywheel masses (3, 4) relative to each other.

1 2. A torque transmitting arrangement according to one of claims 10 or 11 characterised in that, upon release of the friction clutch (7, 107), the damping action of the friction or sliding connection decreases.

1 3. A torque transmitting arrangement according to one of claims 10 to 1 2 characterised in that the damping action of the friction or sliding connection is removed upon release of the friction clutch.

14. A torque transmitting arrangement according to one of claims 10 to 1 3 characterised in that the friction or sliding connection is formed by at least one friction or sliding lining (22, 122) which is provided between the two flywheel masses.

1 5. A torque transmitting arrangement according to claim 1 4 characterised in that the friction or sliding lining is disposed between mutually facing faces of the two flywheel masses whsich are of a disc-like configuration.

1 6. A torque transmitting arrangement according to one of claims 1 4 or 1 5 characterised in that the friction or sliding lining is disposed in an annular arrangement.

1 7. A torque transmitting arrangement according to one of the preceding claims characterised in that, when the friction clutch (7, 107) is not actuated, the friction or sliding lining (22, 122) is gripped between the flywheel masses (3, 4) by the force storage means (34, 36; 134, 136) which urges the two flywheel masses (3, 4) towards or away from each other.

1 8. A torque transmitting arrangement according to one of the preceding claims characterised in that, upon release of the friction clutch (7, 107), the clamping effect on the friction ring (34, 36; 1 34, 136) is removed.

19. A torque transmitting arrangement according to one of the preceding claims characterised in that the clamping effect on the friction ring (22, 122) is reduced upon release of the friction clutch (7, 107) by virtue of the axial displacement (X) between the two flywheel masses (3, 4) which takes place when that occurs.

20. A torque transmitting arrangement according to one of claims 1 to 1 9 characterised in that the two flywheel masses are mounted rotatably relative to each other by way of a rolling bearing (15).

21. A torque transmitting arrangement according to one of claims 1 to 20 characterised in that one of the bearing races (15a) is axially fixed to the second flywheel mass (4) and the other of the bearing races (15b) is axially displaceable on an axial extension portion (18) provided on the first flywheel mass (3).

22. A torque transmitting arrangement according to one of the preceding claims characterised in that the force storage means (34, 134) which urges the flywheel masses (3, 4) towards or away from each other engages the axially displaceable race (15b) of the rolling bearing (15) and secures same against rotary movement relative to the flywheel mass (3) which carries that bearing race.

23. A torque transmitting arrangement according to one of the preceding claims characterised in that the damping means (13) comprises peripherally operative force storage means (21) and/or friction or sliding means (36, 136) which are operative in addition to the friction or sliding connection (22, 122) which is provided between the two flywheel masses (3, 4) and which is variable in dependence on actuation of the friction clutch (7, 107).

24. A torque transmitting arrangement substantially as described with reference to Fig. 1 or Fig. 2 of the drawings.