Abstract
A multi-plate clutch, in particular a dual-plate clutch, for coupling a drivetrain of a motor vehicle engine having at least one transmission input shaft, in particular for a dual clutch is provided, having a counter plate for introducing a torque from the driveshaft, a clutch plate for channeling the torque to the transmission input shaft, the clutch plate having a first lining ring for frictionally engaged torque transfer and a second lining ring which is movable axially relative to the first lining ring for frictionally engaged torque transfer, a separator plate which is movable axially relative to the counter plate, the separator plate being positioned between the first lining ring and the second lining ring in the axial direction, and a contact plate which is movable axially relative to the counter plate by an actuating element to frictionally compress the clutch plate, the first lining ring being positioned between the contact plate and the separator plate in the axial direction and the second lining ring being positioned between the separator plate and the counter plate, there being n separator plates and n+1 lining rings provided, the movement of the separator plate in the axial direction being coupled with the movement of the contact plate in the axial direction by means of a coupling mechanism, where over at least part of the distance between an open position of the contact plate corresponding to the disengaged position of the multi-plate clutch and a maximum closed position of the contact plate corresponding to the engaged position of the multi-plate clutch when the lining rings are worn, a current distance translation ratio i(s.sub.A) of the axial displacement of the contact plate to the axial displacement of the separator plate which is furthest distant in the axial direction from the contact plate at an axial position s.sub.A of the contact plate deviates from i(s.sub.A)=n+1, and/or a current distance translation ratio i(s.sub.A).sub.j of the axial displacement of the contact plate to the axial displacement of a jth separator plate at an axial position s.sub.A of the contact plate deviates from i(s.sub.A).sub.j=(n+1)/j where j is counted starting from the counter plate in the direction of the contact plate. Because the distance translation ratio of the coupling mechanism deviates from n+1, the multi-plate clutch can easily be adapted to differently-dimensioned lining rings, so that transmission of an especially high torque is enabled with the help of a friction clutch with different configurations of a motor vehicle drivetrain.
Claims
1. A multi-plate clutch, in particular a dual-plate clutch, for coupling a driveshaft (12) of a motor vehicle engine to at least one transmission input shaft (16, 18), in particular for a dual clutch (10), having a counter plate (22) for introducing a torque from the driveshaft (12), a clutch plate (32) for channeling the torque to the transmission input shaft (16, 18), the clutch plate (32) having a first lining ring (28) for frictionally engaged torque transfer and a second lining ring (30) which is movable axially relative to the first lining ring for frictionally engaged torque transfer, a separator plate (34) which is movable axially relative to the counter plate (22), the separator plate (34) being positioned between the first lining ring (28) and the second lining ring (30) in the axial direction, and a contact plate (26) which is movable axially relative to the counter plate (22) by an actuating element (24) to frictionally compress the clutch plate (32), the first lining ring (28) being positioned between the contact plate (26) and the separator plate (34) in the axial direction and the second lining ring (30) being positioned between the separator plate (34) and the counter plate (22), there being n separator plates (34) and n+1 lining rings (28, 30) provided, the movement of the separator plate (34) in the axial direction being coupled with the movement of the contact plate (26) in the axial direction by means of a coupling mechanism (44), where over at least part of the distance between an open position of the contact plate (26) corresponding to the disengaged position of the multi-plate clutch (20) and a maximum closed position of the contact plate (26) corresponding to the engaged position of the multi-plate clutch (20) when the lining rings (28, 30) are worn, a current distance translation ratio i(s.sub.A) of the axial displacement of the contact plate (26) to the axial displacement of the separator plate (34) which is furthest distant in the axial direction from the contact plate (26) at an axial position s.sub.A of the contact plate (26) deviates from i(s.sub.A)=n+1 and/or a current distance translation ratio i(s.sub.A).sub.j of the axial displacement of the contact plate (26) to the axial displacement of a jth separator plate (34) at an axial position s.sub.A of the contact plate (26) deviates from i(s.sub.A).sub.j=(n+1)/j, where j is counted starting from the counter plate (22) in the direction of the contact plate (26).
2. A multi-plate clutch according to claim 1, characterized in that the value of the current distance translation ratio i(s.sub.A), at least in a segment between the open position of the contact plate (26) and the maximum closed position of the contact plate (26), in particular at least in a segment between the open position of the contact plate (26) and a closed position of the contact plate (26) that corresponds to the engaged position of the multi-plate clutch (20) with unworn lining rings, is 0.00<|i(s.sub.A)(n+1)|/(n+1)5.0, in particular 0.01|i(s.sub.A)(n+1)|/(n+1)2.5, preferably 0.05|i(s.sub.A)(n+1)|/(n+1)1.5, more preferably 0.07|i(s.sub.A)(n+1)|/(n+1)1.0 and by particular preference 0.10|i(s.sub.A)(n+1)|/(n+1)0.8.
3. A multi-plate clutch according to claim 1 or 2, characterized in that the current distance translation ratio i(s.sub.A) between the open position of the contact plate (26) and the maximum closed position of the contact plate (26), in particular between the open position of the contact plate (26) and a closed position of the contact plate (26) corresponding to the engaged position of the multi-plate clutch (20) with unworn lining rings (28, 30), changes at least once; in particular, the current distance ratio i(s.sub.A) changes continuously.
4. A multi-plate clutch according to one of claims 1 through 3, characterized in that the first lining ring (28) has a first lining springing (50) and the second lining ring (30) a second lining springing (54), the first lining springing (50) being compressible maximally in the axial direction by a first axial distance s.sub.BF1 and the second lining springing (54) being compressible maximally in the axial direction by a second axial distance s.sub.BF2 which differs from the first axial distance s.sub.BF1, where in particular 0.00<2|s.sub.BF1s.sub.BF2|/(s.sub.BF1+s.sub.BF2)2.0, preferably 0.052|s.sub.BF1s.sub.BF2|/(s.sub.BF1+s.sub.BF2)1.7, more preferably 0.102|s.sub.BF1s.sub.BF2|/(s.sub.BF1+s.sub.BF2)1.5 and by particular preference 0.202|s.sub.BF1s.sub.BF2|/(s.sub.BF1+s.sub.BF2)1.0.
5. A multi-plate clutch according to one of claims 1 through 4, characterized in that the first lining ring (28) has a first friction lining (48) with an effective axial first friction lining thickness d.sub.1 and the second lining ring (30) has a second friction lining (52) with an effective second axial friction lining thickness d.sub.2 which differs from the first friction lining thickness d.sub.1, where in particular 00<2|d.sub.1d.sub.2|/(d.sub.1+d.sub.2)<2.0, preferably 0.012|d.sub.1d.sub.2|/(d.sub.1+d.sub.2)1.8, more preferably 0.052|d.sub.1d.sub.2|/(d.sub.1+d.sub.2)1.5 and by particular preference 0.102|d.sub.1d.sub.2|/(d.sub.1+d.sub.2)1.0.
6. A multi-plate clutch according to one of claims 1 through 5, characterized in that when the contact plate (26) moves from the open position to a closed position of the contact plate (26) corresponding to the engaged position of the multi-plate clutch (20) with unworn lining rings (28, 30), the first lining ring (28) and the second lining ring (30) are frictionally compressible at different points in time and/or the compressing begins and/or ends at different points in time.
7. A multi-plate clutch according to one of claims 1 through 6, characterized in that to form the coupling mechanism (44) the contact plate (26) is connected to the counter plate (22) by means of a first leaf spring (38), the separator plate (34) is connected to the counter plate (22) by means of a second leaf spring (40), and the separator plate (34) is supported on the contact plate (26) by means of a contact pin (42) which rests against the first leaf spring (38) or the second leaf spring (40) or some other element which forms a contact point (56, 64).
8. A multi-plate clutch according to claim 7, characterized in that the separator plate (34) is supportable by means of at least two contact points (56, 64) on the first leaf spring (38) which are offset relative to one another in the circumferential direction and/or in the radial direction, to change the current distance translation ratio i(s.sub.A), the at least two contact points (56, 64) being in particular part of the same contact pin (42).
9. A multi-plate clutch according to claim 8, characterized in that the contact pin (42) preferably has a contact contour (66), in particular essentially convex, directed toward the first leaf spring (38), to change the current distance translation ratio i(s.sub.A), in particular continuously, at least in a segment of the axial movement of the contact plate (26).
10. A multi-plate clutch according to one of claims 6 through 9, characterized in that the contact pin (42) is connected to the separator plate (34) and secured against rotation.
11. A multi-plate clutch according to one of claims 6 through 10, characterized in that the contact pin (42) is prestressed pliably in the axial direction with a spring force, and/or the contact pin (42) is provided with an end stop, where the end stop blocks the movement of the contact pin (42) in one axial direction and permits it in the opposite axial direction.
12. A multi-plate clutch according to one of claims 6 through 11, characterized in that the contact pin (42) bends the first leaf spring (38) in an axial direction in the maximum closed position of the contact plate (26), in particular in a closed position of the contact plate (26) corresponding to the engaged position of the multi-plate clutch (20) with unworn lining rings (28, 30).
13. A multi-plate clutch according to one of claims 6 through 12, characterized in that the contact pin (42) is riveted to the separator plate (34), with a contact point (56, 64, 66) of the contact pin (42) that contacts the first leaf spring (38) being offset in the radial direction relative to a rivet shank (74) of the contact pin (42), while in particular the contact point (56, 64, 66), seen in the direction of the rivet shank axis, is positioned completely next to the rivet shank cross section, and/or a bearing area used only for assembly appears as an extension of the rivet shank, the bearing area completely covering the rivet shank cross section.
Description
[0027] The invention will be explained below by way of example with reference to the accompanying drawings, on the basis of preferred exemplary embodiments; the features depicted below can each depict an aspect of the invention, both individually and in combination. The figures show the following:
[0028] FIG. 1: a schematic sectional view of a dual clutch,
[0029] FIG. 2: a schematic perspective view of part of the dual clutch from FIG. 1,
[0030] FIG. 3: a schematic sectional view of an implementation of a multi-plate clutch of the dual clutch from FIG. 1,
[0031] FIG. 4: a schematic sectional view of the multi-plate clutch from FIG. 3 in a disengaged position,
[0032] FIG. 5: a schematic sectional view of the multi-plate clutch from FIG. 3 in a partially engaged position,
[0033] FIG. 6: a schematic sectional view of the multi-plate clutch from FIG. 3 in an engaged position in unworn condition,
[0034] FIG. 7: a schematic sectional view of the multi-plate clutch from FIG. 3 in a maximum engaged position in worn condition,
[0035] FIG. 8: a schematic sectional view of a first embodiment of a multi-plate clutch according to the invention in a disengaged position,
[0036] FIG. 9: a schematic sectional view of the multi-plate clutch from FIG. 8 in a partially engaged position,
[0037] FIG. 10: a schematic sectional view of the multi-plate clutch from FIG. 8 in an engaged position in unworn condition,
[0038] FIG. 11: a schematic sectional view of the multi-plate clutch from FIG. 8 in a maximum engaged position in worn condition,
[0039] FIG. 12: a schematic sectional view of a second embodiment of a multi-plate clutch according to the invention in a disengaged position,
[0040] FIG. 13: a schematic sectional view of the multi-plate clutch from FIG. 12 in a partially engaged position,
[0041] FIG. 14: a schematic sectional view of the multi-plate clutch from FIG. 12 in an engaged position in unworn condition,
[0042] FIG. 15: a schematic sectional view of the multi-plate clutch from FIG. 12 in a maximum engaged position in worn condition,
[0043] FIG. 16: a schematic sectional view of a third embodiment of a multi-plate clutch according to the invention in a disengaged position,
[0044] FIG. 17: a schematic sectional view of the multi-plate clutch from FIG. 16 in a partially engaged position,
[0045] FIG. 18: a schematic sectional view of the multi-plate clutch from FIG. 16 in an engaged position in unworn condition,
[0046] FIG. 19: a schematic sectional view of the multi-plate clutch from FIG. 16 in a maximum engaged position in worn condition,
[0047] FIG. 20: a schematic sectional detail view of a fourth embodiment of a multi-plate clutch according to the invention,
[0048] FIG. 21: a schematic sectional detail view of a fifth embodiment of a multi-plate clutch according to the invention,
[0049] FIG. 22a: a schematic perspective detail view of a sixth embodiment of a multi-plate clutch according to the invention,
[0050] FIG. 22b: a schematic sectional detailed view of the multi-plate clutch from FIG. 22a,
[0051] FIG. 23: a schematic perspective detail view of a seventh embodiment of a multi-plate clutch according to the invention, and
[0052] FIG. 24: a schematic perspective detail view of an eighth embodiment of a multi-plate clutch according to the invention.
[0053] The dual clutch 10 depicted in FIG. 1 may couple a driveshaft 12 via a torsional vibration damper 14 in the form of a dual-mass flywheel to a first transmission input shaft 16 and a second transmission input shaft 18. To this end, a multi-plate clutch 20 is provided in each case, each of which has a counter plate 22 coupled to the driveshaft 12 and a contact plate 26 which is movable with the help of an actuating element 24 in the form of a rigid actuating pot, where the contact plate 26 can also compress a separator plate 34 which is positioned between a first lining ring 28 and a second lining ring 30 of a clutch plate 32, which is movable axially relative to the first lining ring 28. To this end, an actuating force from a hydraulic actuating system 36 may be introduced into the actuating element 24, in particular to engage the multi-plate clutch 20. The contact plate 26 is connected via a first leaf spring 38, and the separator plate 34 via a second leaf spring 40, at least indirectly to the counter plate 22. Connected to the separator plate 34 is a contact pin 42 which makes contact with the first leaf spring 38, whereby a coupling mechanism 44 is formed which motion-couples the separator plate 34 to the contact plate 26 in a defined distance translation ratio.
[0054] Various concepts are presented below for how the separator plates 34 may be guided in the contact plate path of the contact plate 26 in the correct ratio. The distinctive feature of the coupling mechanisms 44 presented here and based on leaf springs 38, 40 is that they can guide the separator plates 34 precisely in accordance with the requirements, even when there are friction packages of the clutch plate 32 having different plate and lining variants and/or different removal volumes per lining ring 28, 30. Furthermore, a concept is also proposed which changes the distance translation ratio between the contact plate path of the contact plate 26 and the separator plate path of the separator plate 34 depending on the wear condition of the clutch 20.
[0055] The basic structure of the multi-plate dual clutch 10 is visible in FIG. 1. The actuating forces of the clutch actuation system 36 can be transmitted to the contact plates 26 of the sub-clutches 20 by means of actuating bearings 46 and pressure pots 24. The friction package of the respective sub-clutch 20 is then compacted by the contact force which thus develops. The friction package contains the contact plate 26, the first lining ring 28, the separator plate 34, the second lining ring 30 and the axially stationary counter plate 22. The two lining rings 28, 30 of a sub-clutch 20 together form a multi-part clutch plate 32, each part of which is connected axially movably but torsionally rigidly to one of the transmission input shafts 16, 18. The contact plate 26 and the separator plate 34 are connected to the clutch 20 so that they are axially movable but fixed in the radial and tangential directions. Since only the contact plate 26 is actively moved by the actuating system 36, the separator plate 34 moves depending on the contact plate 26. The way the contact plate movement is distributed over the removal volume of the two lining rings 28, 30 (removal volume refers to the increase in the gap dimension between the plates 22, 26, 34 adjacent to the lining rings 28, 30 in excess of the clamped plate thickness) depends on the movement of the separator plate 34 which is located between the two lining rings 28, 30 of the friction package. The way in which the separator plate 34 moves relative to the contact plate 26 thus has great influence on the behavior of the clutch 20. The correct movement diagram makes it possible to ensure that both lining rings 28, 30 of the clutch plate 32 can clear (disengage) correctly, and when the individual lining rings 28, 30 become engaged or are again disengaged during the engaging or disengaging process. Since the movement of the separator plate 34 is important, the separator plate 34 should be guided exactly depending on the movement of the contact plate. To this end, various embodiments of the mechanical coupling mechanism 44 are presented below.
[0056] As shown in FIG. 2, the separator plates 34 and the contact plates 26 are connected by means of leaf springs 38, 40 with parts that are fixed relative to the clutch. The leaf springs 38, 40 serve to center the plates 26, 34 and to transmit torque. At the same time, the leaf springs 38, 40 are elastic in the axial direction and thus make guided axial movement of the separator and contact plates 26, 34 possible. Both plates 26, 34 have a plurality of leaf springs 38, 40 or leaf spring assemblies distributed around their circumference. In order to synchronize the separator plate movement in the correct relationship to the contact plate movement, the separator plate 34 is supported on one or more first leaf springs 38 of the contact plate 26.
[0057] The basic principle is shown in FIG. 3, in which the three platescontact plate 26, separator plate 34 and counter plate 22are depicted schematically, between which the two lining rings 28, 30 of the clutch plate 32 are located. The first lining ring 28 has a first lining springing 50 provided on both sides with a first friction lining 48, while the second lining ring 30 has a second lining springing 54 provided on both sides with a second friction lining 52. Both the contact plate 26 and the separator plate 34 are connected by means of their own leaf springs 38, 40 to the counter plate 22, which is fixed relative to the clutch. Thus, the transmission of force and the centering occur in each case directly between the movable plate (contact plate 26 or separator plate 34) and the components which are fixed relative the clutch 20 (represented here by the counter plate 22), without tangential forces and centering effect being transmitted from one of the movable plates 26, 34 to the other. Since FIG. 3 depicts only a section of a simplified implementation, in each case only one leaf spring 38, 40 is visible, which holds the contact plate 26 and the separator plate 34. It makes sense, however, to distribute a plurality of leaf springs 38, 40 around the circumference, in particular uniformly, each of which is connected on one side to the movable plate 26, 34 and on the other side to a component which is fixed relative to the clutch 20. Three positions distributed around the circumference have proven especially effective for the arrangement of the leaf springs 38, 40. It is also possible for multiple leaf springs 38, 40 to be positioned (stacked) on top of another. If the second leaf springs 40, which hold the separator plate 34, also always apply force to it in the direction of the contact plate 26 and thus in the disengagement direction of the clutch 20, simple contact points 56 are adequate to guide the separator plate 34. The contact points 56 do not lift off of the first leaf springs 38 when the clutch is disengaged 20 because of the axial force of the second leaf springs 40. Only when the clutch 20 is completely or partially engaged can the contact lift off, when the lining resiliencies 50, 54 of the two lining rings 28, 30 push the separator plate 34 into a different position than is provided for at this moment with the help of the leaf springs 38, 40 through the geometric distance coupling of the coupling mechanism 44.
[0058] To ensure that the separator plate 34 takes the correct position relative to the contact plate 26 and the counter plate 22, in particular with the clutch 20 disengaged, a guiding or coupling mechanism 44 for the separator plate 34 is formed with the help of the leaf springs 38, 40. As FIG. 3 shows, the separator plate 34 is supported on one or more first leaf springs 38 of the contact plate 26, in order to synchronize the separator plate movement in the correct ratio with the contact plate movement. Since the first leaf springs 38 are tied on one side to an axially fixed clutch component and on the other side to the contact plate 26, each leaf spring 38 carries out no axial movement on one side and on the other side the axial movement of the contact plate 26. The middle area of the first leaf spring 38 performs a smaller movement than the contact plate 26. How large this movement is depends on the circumferential position. The closer the approach to the connecting point on the contact plate 26, the greater the axial travel becomes. And leaf spring areas that are in the vicinity of the axially fixed connecting point perform almost no axial movement. Thus, the relationship of contact plate movement and separator plate movement can be established by choosing the right support position with the help of the contact pin 42. If the support point on the circumference of the clutch 20 is pushed in the direction of the contact plate attachment, the separator plate travel increases relative to the contact plate travel, and if the support point is shifted in the other direction, in the direction of the fixed connecting point, the separator plate travel is reduced. The first leaf spring 38 functions similarly to a lever that is used for distance translation. This coupling mechanism 44 of the two movable plates 26, 34 ensures that when the clutch 20 disengages, both lining rings 28, 30 of a clutch plate 32 really are relieved and disengaged, and not for example that one lining ring 28, 30 is cleared too far and the other lining ring 30, 28 in exchange too little.
[0059] The exact function of the separator plate guidance with the help of the coupling mechanism 44 will now be described on the basis of the subsequent figures. A basic layout diagram will be used for this, which shows the three platescounter plate 22, separator plate 34 and contact plate 26and the two lining rings 28, 30. These parts depicted in the lower area of the basic layout diagram correspond to a radial section through the clutch 20. Also shown is a first leaf spring assembly having a plurality of first leaf springs 38, which connects the contact plate 26 to the counter plate 22 and on which the separator plate 34 may be supported. This upper area of the basic layout diagram corresponds to the tangential course of the arrangement of the first leaf springs 38 in the clutch 20. To be able to better depict the movement of the movable plates 26, 34, in the figure, the contact plate 26 and the separator plate 34 are also each supplied with imagined pointers 58, 60 which indicate the movement or position change of the plates 26, 34 on an imagined fixed scale 62.
[0060] The first FIGS. 4 through 7 show the coupling mechanism 44 in the form of a leaf spring guide in a clutch 20 having two equivalently constructed lining rings 28, 30, in which the lining springing 50, 54, the necessary clearing distance and the lining wear which occurs over the life of the clutch are exactly the same. An especially preferred embodiment of the invention will not be explained until subsequently, when the solutions for the unlike lining rings 28, 30 are presented. However, for an easier start, and as a starting basis for the variants which are more difficult to understand, the coupling mechanism 44 for like lining rings 28, 30 will nevertheless be described here.
[0061] FIG. 4 shows the leaf spring guide with the clutch 20 disengaged, with the contact plate 26 in an open position. Both lining rings 28, 30 are completely load-free, so that the lining springing 50, 54 has assumed its greatest thickness. In addition, the clutch 20 is disengaged, so that both between the counter plate 22 and the separator plate 34 and between the separator plate 34 and the contact plate 26 there is a greater interval than the unclamped thickness of the lining rings 28, 30, and thus another gap exists between the lining rings 28, 30 and their neighbor components 22, 34, 26, at least on one side of each lining ring 28, 30. Since the focus here is on a leaf spring guide of the coupling mechanism 44 for like lining rings 28, 30, the separator plate 34 is supported exactly in the middle of the free area of the first leaf spring assembly 38, which is not supported by its neighbor components 22, 26. In this embodiment, the contact point 56 is realized by a contact pin 42 in the form of a rivet with a round-topped head.
[0062] FIG. 5 shows the leaf spring guide 44 with the contact plate 26 moved slightly inward. Since the separator plate 34 is supported exactly in the middle of the leaf spring assembly 38, in principle the separator plate travel is essentially exactly half as great as the contact plate travel. This is also indicated by the two pointers 58, 60 on the scale 62. This reduces the interval between the counter plate 22 and the separator plate 34 by the same measure as the interval between the separator plate 34 and the contact plate 26. In the depicted example, this has now led to the result that for both lining rings 28, 30 the separation distance has disappeared and the lining rings 28, 30 are now in contact with their neighbor components 22, 34, 26 on both sides.
[0063] In FIG. 6, the clutch 20 has been engaged still further, so that the lining springing 50, 54 of both lining rings 28, 30 has also been compressed. As soon as the lining springings 50, 54 of the two lining rings 28, 30 are compressed, their forces also act in the axial direction on the separator plates 34, and not only the forces of the leaf springs 38, 40 and of the coupling mechanism 44. With like lining rings 28, 30 having the same lining springing 50, 54, the separator plate 34 is always in axial force equilibrium when the lining springing 50, 54 of the two lining rings 28, 30 is compressed the same distance. This is the case when the separator plate 34 is always moved half as far as the contact plate 26, whereby in this example the force equilibrium of the lining springing 50, 54 always wants to place the separator plate 34 in the same position as the leaf spring guide 44. Both mechanisms, leaf spring guide 44 and force equilibrium therefore work together without any problems. This is also true in the case of advancing lining wear, as long as it occurs with equal severity on both lining rings (FIG. 7).
[0064] A preferred embodiment of the invention is depicted in FIGS. 8 through 11, in which a leaf spring guide 44 for a clutch 20 having different lining rings 28, 30 is depicted. To this end, by way of example, the second lining ring 30 between the counter plate 22 and the separator plate 34 is equipped with none or only very little second lining springing 54. The first lining ring 28 between the separator plate 34 and the contact plate 26 on the other hand has a long first lining springing 50. Because of the different lengths of lining springing 50, 54, the lining rings 28, 30 now also require different removal volumes, so that both can be cleared sufficiently far but not farther than necessary. The separator plate 34 therefore now no longer travels half the distance of the contact plate 26, but is guided by the coupling mechanism 44 so that it travels less than half of the contact plate distance. The separator plate 34 therefore continues to be supported on the free leaf spring area between the two leaf spring linking points, but the support point is positioned so that its distance from the axially immovable attachment point of the first leaf spring 38 to the counter plate 22 is significantly shorter than the distance to the movable connection point of the first leaf spring 38 with the contact plate 26.
[0065] When different lining rings 28, 30 are used in a clutch 20, frequently not only the lengths of the lining springing 50, 54 and/or the removal volumes and/or disengagement distances are different, but the ratios between the lining springing lengths and the disengagement distance may also be different. If this ratio is not the same, with the coupling mechanism 44 shown in this exemplary embodiment, which guarantees a constant (or approximately constant) distance translation ratio between the movable plates 26, 34, it is not possible to guarantee a simultaneous start of the torque build-up at both lining rings 28, 30 without having to accept an unwanted tensioning of the clutch mechanism 44 when the clutch is completely engaged. FIG. 9 shows therefore that with this exemplary embodiment, when the clutch 20 is slightly engaged, the first lining ring 28 with the long first lining springing 50 first touches its two neighbor components 26, 34, and the second lining ring 30 with the shorter second lining springing 54 is not yet clamped. This differing torque build-up is accepted intentionally with this exemplary embodiment, so that when the clutch 20 is completely engaged, the coupling mechanism 44 orients the separator plate so that the contact point 56 rests against the first leaf spring 38 with (almost) no force. To that end the coupling mechanism 44 must place the separator plate 34 exactly in the position of axial force equilibrium of the two lining springings 50, 54 and the two separator plate leaf spring forces (FIG. 10). The distance translation of the coupling mechanism 44 can naturally also only be coordinated with the clearing distances of the two lining rings 28, 30 without allowing for the different lining springing lengths, so that the buildup of torque begins simultaneously at both lining rings 28, 30. But then the coupling mechanism 44 no longer becomes force-free when the clutch 20 is completely engaged, but is tensioned by the lining springings 50, 54, which want to push the separator plate 34 into a different position than the coupling mechanism 44. This can be accepted if the coupling mechanism 44 tolerates this (for example through first leaf springs 38 matched thereto as in FIG. 19 or by a pre-tensioned contact pin 42 as in FIG. 21).
[0066] The distances which the contact plate 26 and the separator plate 34 travel also change during operation of the clutch 20, since the friction lining 48, 52 of the lining rings 28, 30 wears. The lining wear on the two lining rings 28, 30 of a clutch plate 32 occurs uniformly in most cases, so that both lining rings 28, 30 become thinner by about the same amount over time. The contact plate 26 must therefore be moved farther and farther inward in order to compress the friction package completely. But since the coupling mechanism 44 of this exemplary embodiment always wants to move the separator plate 34 less than half the distance of the contact plate, the coupling mechanism 44 does not guide the separator plate 34 far enough to bring the separator plate 34 actively into the equilibrium position of the lining springings 50, 54 and the leaf spring forces with the same lining wear. The result is that the contact points 56 connected to the separator plate 34 lift off of the first leaf springs 38 (FIG. 11).
[0067] As the description of the exemplary embodiment depicted in FIGS. 8 through 11 shows, with a constant distance translation of the coupling mechanism 44 it is not possible to react individually to boundary conditions which change the distance relationships between the two lining rings 28, 30. Remedy is provided by a coupling mechanism 44 having changeable distance translation. This translation change can be achieved, for example, by two contact points 56, 64 per contact pin 42 between the separator plate 34 and the first leaf springs 38. Starting from a certain engagement travel, the first leaf spring 38, because of its changed inclination, rests on the formerly non-bearing second contact point 64, and in exchange releases the first contact point 56, which had been in contact until then. Since the two contact points 56, 64 are offset around the circumference of the clutch 20 and thus are at a different distance from the axially fixed and the axially movable tie-in of the first leaf spring 38, the distance translation of the coupling mechanism 44 changes. The operating principle is illustrated in FIGS. 12 through 15. The basic layout diagrams of FIGS. 12 through 14 differ from the embodiment depicted in FIGS. 8 through 10 only by the second contact point 64 of the contact pin 42. The lining rings 28, 30, the contact plate paths, the separator plate path and the behavior of the clutch 20 are exactly as described before. Only when the friction linings 48, 52 are worn does the second contact point 64 come to bear. And since the change of the contact points 56, 64, and thus the change of the distance translation is distance-dependent, depending on the axial position of the contact plate 26, a clutch 20 with little wear will also travel only a small distance with the second distance translation stage, and a severely worn clutch 20 a large distance. This makes it possible to tune the ratio from the distances that the separator plate 34 travels with the first distance translation ratio and the second distance translation ratio so that it always corresponds to the ratio from removal volume in new condition and the increase in removal volume due to wear. Hence, it is possible that both with a new clutch 20 and with a completely worn clutch 20 the coupling mechanism 44 is always force-free, or at least almost force-free, when the clutch 20 is fully engaged and fully closed for maximum transmission of torque.
[0068] The translation change of the distance translation can be achieved not only by two contact areas 56, 64 spaced apart, but also by a continuous contact contour 66, on which the first leaf spring 38 rests at a different location, depending on its angular position. It is possible then through the form of the contact pin 42 to determine not only the largest and smallest distance translation of the coupling mechanism 44, but also the course of the translation change. A continuous contact contour 66 therefore provides for a continuous translation change, in which all intermediate values of the distance translation occur. When and how rapidly the distance translation changes can be controlled by the three-dimensional form of the contact contour 66. To achieve a continuous translation change with flat first leaf springs 38, convex contact contours 66 in particular are employed. Alternatively, the contact pin 42 may also be designed with more than two contact points 56, 64, so that also more than two translation steps are produced. With a coupling mechanism 44 having multiple translation steps or a continuous translation change, at the beginning of the engaging process, for example, the coupling mechanism 44 may provide a translation ratio which is matched to the clearing distances of the two lining rings 28, 30. Next, the translation ratio may change, so that it is optimally tuned for the lining springing distances, and then the coupling mechanism 44 can adjust to the anticipated lining wear with a new translation change.
[0069] As described for the previous exemplary embodiments, it is possible that the torque build-up does not begin simultaneously in the two lining rings 28, 30 of a sub-clutch 20. Since the number of effective friction surfaces decides how much torque can be transmitted at a certain contact force, the clutch properties can be influenced greatly by the simultaneous or staggered torque build-up. Depending on the demands on the clutch 20, a simultaneous or staggered start of the torque transmission may make sense. How the torque build-up takes place can be determined by the distance translation of the coupling mechanism 44 and/or the removal volume length. So, FIG. 5, for example, shows a simultaneous start of torque, and FIGS. 9 and 13 show examples in which the first lining ring 28 on the contact plate side is the first to come into contact. Another exemplary embodiment, in which the second lining ring 30, which fits against the counter plate 22, is the first to come into contact, is shown in FIGS. 16 through 19. To make it clear that the different torque build-up occurs not only with different lining rings 28, 30, two like lining rings 28, 30 are used in the basic layout diagrams, whereas preferably differently shaped lining rings 28, 30 are used.
[0070] So that the second lining ring 30 is the first to make contact with the counter plate 22, on the one hand it is less strongly cleared than the other first lining ring 28 on the contact plate 26, and on the other hand the distance translation of the coupling mechanism 44 is tuned so that the separator plate 34 travels more than half the contact plate distance (FIGS. 16 and 17). The two measures, which are combined here, can also lead to the desired result individually. If the clutch 20 is engaged further after the start of torque transmission caused by the second lining ring 30 in contact with the counter plate 22, because of the lining springing force building up on one side, the separator plate 34 does not travel as far as it theoretically should because of the distance translation ratio of the coupling mechanism 44. This increases the force at the contact points 56 between the separator plate 34 and the first leaf springs 38, and the componentsin particular the first leaf springs 38are bent elastically (FIG. 18). If the first leaf springs are designed for this additional bending load, longer engagement distances can be realized, such as occur for example due to lining wear (FIG. 19). Alternatively, the elastic deformation may also be distributed over additional spring elements 68. FIG. 21 shows for this, for example, a contact pin 42 pre-tensioned in the separator plate 34 with the help of the spring element 68, for example in the form of a diaphragm spring. If the contact force exerted by the contact pin 42 on the first leaf springs 38 exceeds the force of the pre-tensioned spring element 68, then the contact pin 42 is shifted relative to the separator plate 34 and thereby reduces the bending of the first leaf springs 38.
[0071] In the coupling mechanisms 44 described here, the first leaf springs 38, which hold the contact plate 26, fulfill three basic tasks. They hold and center the contact plate 26, they always press the contact plate 26 in the disengagement direction, and they serve as a translation lever for the coupling mechanism 44 of the separator plate 34. These tasks may also be distributed among various components. The coupling mechanism 44, as it is presented here, has a translation element which is connected on one side to a component which is fixed axially relative to the clutch 20 and on the other side is moved along with the contact plate movement, so that between the two outer tie-in points the correct axial distance for the separator plate 34 can be measured out. Whether this coupling element is a leaf spring 38 or a lever-like element of some other design is not crucial for the operating principle of the coupling mechanism 44. One or more leaf springs 38, 40 may be utilized as a translation element, even if they do not fulfill the other clutch-relevant functions previously enumerated. Furthermore, the contact pin 42 or some other coupling element may be connected to the contact plate 26 and be supported on the second leaf spring 40, which is connected to the separator plate 34. Furthermore, in comparison to the clutch 20 designed by way of example on the basis of a dual-plate clutch, more than one separator plate 34 may be provided, which may be coupled with the contact plate 26 accordingly by means of one of the coupling mechanisms 44 described above.
[0072] In the contact points 56, 64 between the separator plates 34 and the first leaf springs 38, which fix the contact plates 26, what is important basically is not the design but only the contact, so that the first leaf springs 38 can move the separator plate 34 in the axial direction. Nevertheless, there are naturally certain solutions which are especially appropriate technically, such as the variants presented below.
[0073] FIG. 20 shows the contact pin 42, which has already been designed repeatedly in the previous figures as a support rivet. The rivet 42 can be connected easily to very different separator plates 34 and separator plate materials. In addition, the rivet 42 can very easily be hardened, coated, or made of an especially hard or lubricious material. This enables the contact point 56 to be made robust and subject to little wear, and can reduce the hysteresis due to friction. The exemplary embodiment shows a rivet with two contact points 56, 64. Both the center elevation and the edge of the rivet head may be utilized as contact points 56, 64. Either one or both contact points 56, 64 may be realized and used. A rivet 42 having two contact points 56, 64 is especially attractive for coupling mechanisms 44 having changeable translation, since this eliminates the need of placing two individual rivets 42 side-by-side. In addition, a continuous transition contour 66 between the two contact points 56, 64 spaced at a maximum interval can also enable and influence a continuous translation change of the distance translation.
[0074] Instead of rotationally symmetrical rivets, the contact pins 42 may also be designed as shaped rivets, which offer the first leaf spring 38 a larger supporting surface and can make linear contact possible. If the rivet 42 is no longer rotationally symmetrical, it should be connected to the separator plate 34 in the correct orientation to achieve the correct separator plate position and the desired distance translation. FIGS. 22a and 22b show by way of example the shaped rivet 42 with the two contact points 56, 64, which is already known from the exemplary embodiment with changeable translation (FIGS. 12 through 15). In the detailed illustrations it can be seen how the shaped rivet 42 can be aligned on an axially protruding bar 72 of the contour of the separator plate 34 by means of an outer contour 70 of its non-round head. The bar 72 of the separator plate 34 simplifies the assembly alignment, and prevents the rivet 42 from unwanted turning, even during operation of the clutch.
[0075] Two other exemplary embodiments, in which the rivet 42 is aligned by a flattened rivet shank 74, are shown in FIGS. 23 and 24. The rivet heads have an axially protruding contact bar 76 that forms the contact contour 66, by which the separator plates 34 can be supported on the first leaf springs 38. The course of the distance translation can be controlled by the contour 66 of the contact bar 76. A continuous, mostly convex curvature of the contact bar 76 makes it very simple to elicit a continuous translation change, which can be adapted in particular to the lining springings 28, 30, the clearing distances and lining wear rates. To prevent damage to the contact bar 76 while the rivet 42 is being set, the riveting die may be braced next to the contact contour 66 which the first leaf springs 38 utilize. The supporting surfaces for the riveting may be located on both sides of the contact bar 76 (FIG. 23). Alternatively, a single supporting surface for the riveting process may also be provided on one side of the contact bar 76 (FIG. 24). It is expedient in this case not to locate the contact bar 76 directly extending the axis of the rivet shank 74, so that the supporting surface can largely or completely cover the rivet shank 74.
[0076] FIG. 21 shows a contact pin 42 which is inserted into an opening 78 in the separator plate 34 so that it is axially movable. On one side of the separator plate 34 the pin shaft 80 is provided with a locking ring 82, which serves as a stop and is braced against the separator plate 34. On the other side is the pin head with the contact contour 66. Between the pin head and the separator plate 34 is a pre-tensioned diaphragm spring 68, which presses the contact pin 42 against the stop formed by the locking ring 82. Because of the pre-tensioning force of the diaphragm spring 68, the contact pin 42 acts like a rigid contact point 56 and fulfills all characteristics described previously for the contact points 56, 64, as long as the contact force does not exceed the pre-tensioning force of the diaphragm spring 68. If this is the case, the contact pin 42 is shifted relative to the separator plate 34. This can limit the maximum axial forces exerted on the separator plate 34 by the coupling mechanism 44, and/or change distance ratios depending on the force.
[0077] Leaf springs 38, 40 are mainly used in dry dual clutches 10, because of their low friction. All concepts presented here may also be employed in wet-running clutches, however.
REFERENCE LABELS
[0078] 10 dual clutch [0079] 12 drive shaft [0080] 14 torsional vibration damper [0081] 16 first transmission input shaft [0082] 18 second transmission input shaft [0083] 20 multi-plate clutch [0084] 22 counter plate [0085] 24 actuating element [0086] 26 contact plate [0087] 28 first lining ring [0088] 30 second lining ring [0089] 32 clutch plate [0090] 34 separator plate [0091] 36 actuating system [0092] 38 first leaf spring [0093] 40 second leaf spring [0094] 42 contact pin [0095] 44 coupling mechanism [0096] 46 actuating bearing [0097] 48 first friction lining [0098] 50 first lining springing [0099] 52 second friction lining [0100] 54 second lining springing [0101] 56 contact point [0102] 58 first pointer [0103] 60 second pointer [0104] 62 scale [0105] 64 second contact point [0106] 66 contact contour [0107] 68 spring element [0108] 70 outside contour [0109] 72 bar [0110] 74 rivet shank [0111] 76 contact bar [0112] 78 opening [0113] 80 pin shaft [0114] 82 locking ring
