FRICTION PLATE

Abstract

A friction plate for a wet multiplate clutch includes a carrier element and a friction lining. The friction lining is adhesively bonded to the carrier element, is formed of friction lining pieces, and includes at least four annular sectors. A first one of the at least four annular sectors has a first groove pattern. A second one of the at least four annular sectors has a second groove pattern, different than the first groove pattern.

Claims

1-10. (canceled)

11. A friction plate for a wet multiplate clutch comprising: a carrier element; and, a friction lining, adhesively bonded to the carrier element, formed of friction lining pieces, and including at least four annular sectors, wherein: a first one of the at least four annular sectors comprises a first groove pattern; and, a second one of the at least four annular sectors comprises a second groove pattern, different than the first groove pattern.

12. The friction plate of claim 11, wherein the at least four annular sectors comprises: a first type of annular sector with a first groove pattern; and, a second type of annular sector with a second groove pattern, different than the first groove pattern.

13. The friction plate of claim 12, wherein the first type of annular sector is arranged alternately with the second type of annular sector in a circumferential direction in an A, B, A, B pattern where A denotes the first type of annular sector and B denotes the second type of annular sector.

14. The friction plate of claim 12, wherein a first one of the first type of annular sector is adjacent to a second one of the first type of annular sector.

15. The friction plate of claim 14, wherein pairs of the first type of annular sector are arranged alternately with pairs of the second type of annular sector in a circumferential direction in an A, A, B, B pattern where A denotes the first type of annular sector and B denotes the second type of annular sector.

16. The friction plate of claim 11 wherein each one of the at least four annular sectors has the same shape and size as the other ones of the at least four annular sectors.

17. The friction plate of claim 11, wherein the first one of the at least four annular sectors comprises a stamped groove pattern.

18. The friction plate of claim 11 wherein the first one of the at least four annular sectors comprises a plurality of the friction lining pieces spaced apart from one another to form a groove pattern having grooves with groove bottoms formed by the carrier element.

19. The friction plate of claim 11, wherein each one of the at least four annular sectors is spaced apart from the other ones of the at least four annular sectors in a circumferential direction to form a radially extending groove having a groove bottom formed by the carrier element between pairs of the at least four annular sectors.

20. The friction plate of claim 11, wherein a quantity of the at least four annular sectors is less than or equal to six times an internal radius of the friction plate in centimeter units.

21. A friction plate comprising: a carrier plate including a first plurality of annular sectors; a first friction lining arranged on a first one of the first plurality of annular sectors and including a first groove pattern; and, a second friction lining arranged on a second one of the first plurality of annular sectors and including a second groove pattern, different than the first groove pattern.

22. The friction plate of claim 21 wherein the first friction lining is a first plurality of friction lining pieces and the first groove pattern is formed as grooves between each one of the first plurality of friction lining pieces.

23. The friction plate of claim 22 wherein the first groove pattern is a rain tire design.

24. The friction plate of claim 23 wherein the second friction lining is a second plurality of friction lining pieces and the second groove pattern is formed as radial grooves between each one of the second plurality of friction lining pieces.

25. The friction plate of claim 22 wherein the second friction lining is a single friction lining piece and the second groove pattern is a stamped waffle design or a stamped micro waffle design.

26. The friction plate of claim 21 wherein: the first friction lining is a single friction lining piece and the first groove pattern is a stamped groove pattern; and, the second friction lining is a single friction lining piece and the second groove pattern is a stamped groove pattern.

27. The friction plate of claim 26 wherein the first groove pattern is a waffle design and the second groove pattern is a micro waffle design.

28. The friction plate of claim 21 wherein the first friction lining and the second friction lining are arranged on the first plurality of annular sectors in an A,B,A,B pattern or an A,A,B,B pattern where A denotes the first friction lining and B denotes the second friction lining.

29. The friction plate of claim 21 wherein the first friction lining and the second friction lining are affixed to the first plurality of annular sectors by adhesive bonding.

30. The friction plate of claim 21 wherein: the carrier plate comprises a first axial side and a second axial side; the first plurality of annular sectors is disposed on the first axial side; a second plurality of annular sectors is disposed on the second axial side; and, the friction plate comprises: a third friction lining arranged on a first one of the second plurality of annular sectors and including a third groove pattern; and, a fourth friction lining arranged on a second one of the second plurality of annular sectors and including a fourth groove pattern, different than the third groove pattern.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Further advantages, features and details of the dislosure will emerge from the following description, in which various illustrative embodiments are described in detail with reference to the drawings. In the drawings:

[0034] FIG. 1 shows a simplified section through an axial double clutch having two sub-clutches embodied as multiplate clutches;

[0035] FIG. 2 shows an enlarged detail of FIG. 1 having two axially nested plate packs;

[0036] FIG. 3 shows a detail view of a friction plate in section;

[0037] FIG. 4 shows a simplified illustration of various friction linings for the friction plate from FIG. 3 in plan view;

[0038] FIG. 5 shows an enlarged detail of FIG. 4 in section, wherein the illustration is not to scale or is independent of a friction lining thickness; and

[0039] FIGS. 6 to 10 show further illustrations of friction linings for the friction plate from FIG. 3 in plan view.

DETAILED DESCRIPTION

[0040] An axial double clutch 10 having two axially nested sub-clutches 1, 2 is illustrated in simplified form in FIG. 1. The sub-clutches 1, 2 are embodied as wet multiplate clutches. Wet means that a cooling medium, such as cooling oil, also referred to for short as oil, is fed to the multiplate clutches 1, 2 for cooling.

[0041] The multiplate clutch 1 includes a hub 3, which can be connected for conjoint rotation to a transmission input shaft (not shown). The multiplate clutch 2 includes a hub 4, which can be connected for conjoint rotation to a second transmission input shaft (likewise not shown), which is may be embodied as a hollow shaft.

[0042] The two multiplate clutches 1, 2 include a common input part 5. The input part 5 is connected for conjoint rotation to a drive shaft (not shown). A bearing device 6 is arranged between the input part 5 and the hub 3 of the multiplate clutch 1. A further bearing device 7 is arranged between the two hubs 3, 4 of the multiplate clutches 1, 2.

[0043] The input part 5 of the double clutch 10 is connected for conjoint rotation to a common outer plate carrier 8 for both multiplate clutches 1, 2. The outer plate carrier 8 is rotatably mounted relative to a fixed housing with the aid of a bearing device 9. The fixed housing is indicated only by a symbol at bearing device 9.

[0044] The multiplate clutch 1 includes an inner plate carrier 11, which is connected for conjoint rotation to the hub 3. The multiplate clutch 2 includes an inner plate carrier 12, which is connected for conjoint rotation to the hub 4. An axis of rotation of the double clutch 10 is indicated by a chain dotted line 13. The hubs 3, 4 can rotate relative to one another and relative to the outer plate carrier 8 about the axis of rotation 13.

[0045] A supporting element 15, which extends radially inward in steps from the outer plate carrier 8, is secured on the outer plate carrier 8. The supporting element 15 is used for the axial support of actuation elements 16, 18 via the spring elements 17, 19.

[0046] Actuation element 16 is used to actuate multiplate clutch 1 and extends through a plate pack of multiplate clutch 2. Actuation element 18 is used to actuate multiplate clutch 2.

[0047] An arrow 21 indicates an actuating force, which is applied to actuation element 16 via an actuation bearing 23 in order to actuate multiplate clutch 1. An arrow 22 indicates an actuating force, which is applied to actuation element 18 via an actuation bearing 24 in order to actuate multiplate clutch 2.

[0048] As indicated by the arrows 21, 22, the axially nested wet double clutch 10 illustrated in simplified form in FIG. 1 is actuated from one side, the side on the right in FIG. 1, with a passage through for the actuation of multiplate clutch 1. In such axial double clutches, in which the individual multiplate clutches 1, 2 are arranged axially in series, the thickness of the individual plates is of decisive importance for managing with the axially available installation space.

[0049] In the partial view of FIG. 1 illustrated in FIG. 2, it can be seen that the first multiplate clutch 1 includes a total of seven outer plates 31, 32 and a total of six friction plates 33. The outer plates 31, 32 and the friction plates 33 are arranged alternately in a plate pack in such a way that in each case one friction plate 33 is arranged between two outer plates 31, 32.

[0050] Multiplate clutch 2 includes a plate pack with a total of seven outer plates 41, 42 and six friction plates 43 situated axially adjacent to the plate pack of multiplate clutch 1. The outer plates 41, 42 are arranged alternately with the friction plates 43 in the multi-plate pack of multiplate clutch 2 which is on the right in FIG. 2, in precisely the same way as the plates in the plate pack of multiplate clutch 1 which is arranged on the left in FIG. 2.

[0051] The outer plates 31, 32 and 41, 42 of the multiplate clutches 1, 2 are embodied as steel plates. The required heat capacity of the steel plates entails a lower limit in the thickness thereof, which, depending on the requirements on the respective clutch, especially as regards the energy input, cannot be exceeded since otherwise the temperatures which arise during the operation of the multiplate clutches 1, 2 would assume values that are too high.

[0052] Limits are likewise imposed by dimensional accuracy, in particular flatness due to undulation/conicity, e.g., in the handling of the parts during assembly, especially as regards susceptibility to accidental bending, or the stiffness of the plates, which has an effect on the pressure distribution in the plate pack.

[0053] The outer plates 31, 32; 41, 42 of the multiplate clutches 1; 2 are provided with external teeth, which are used to form a connection for conjoint rotation to the common outer plate carrier 8. The friction plates 33; 43 of the multiplate clutches 1; 2 are provided with internal teeth, which are used to form a connection for conjoint rotation to the associated inner plate carrier 11; 12.

[0054] The friction plate 33 from FIG. 2 is illustrated in cross section on an enlarged scale in FIG. 3. The friction plate 33 includes a carrier element 50, which is fitted with friction linings 51, 52 on two mutually opposite sides. The friction linings 51, 52 can be formed integrally or in several parts.

[0055] The friction linings 51, 52 are preferably paper linings. The paper linings 51, 52 are firmly connected in a materially integral manner, e.g., by adhesive bonding, to the carrier element 50. A thickness of friction lining 52 is denoted by arrow 53, 54.

[0056] The carrier element 50 is embodied, for example, as a carrier plate 55 with a defined thickness, as indicated by arrows 56, 57. Radially on the inside, carrier plate 55 is advantageously equipped with internal toothing, which is used for connection for conjoint rotation to the inner plate carrier (11 in FIG. 2) of the multiplate clutch.

[0057] As for the steel plates, i.e. the outer plates 31, 32; 41, 42, there are likewise lower limits for the thickness of the carrier elements 50, in particular carrier plates 55, especially as regards surface pressure at the tooth contact. The lining thickness 53, 54 of the friction lining 52 furthermore has an effect on the drag torques which occur during operation. Moreover, the lining thickness 53, 54 of friction lining 52 is a decisive parameter for oil flow occurring through the lining grooves during the operation of the multiplate clutch.

[0058] In multiplate clutches, the oil flow from radially on the inside to radially on the outside is inherent in the principle involved and results from the inertia of the oil and from the rotation of the clutch components, which take the oil along and impart to it a rotary motion. Here, the oil is part of a tribological system of the multiplate clutch together with the friction lining, which is usually formed from paper, and the mating plates or outer plates, which are usually embodied as steel plates.

[0059] Conventional friction linings have a thickness of 0.75 millimeters, for example. In order to save axial installation space, it is possible to reduce the friction lining thickness, in particular paper thickness, if, by way of compensation, the groove design or lining pattern of the groove is modified in such a way that the trend is toward the provision of wider and/or deeper grooves in order to avoid significantly restricting the flow cross sections since this, in turn, could have a negative effect on the operation of the multiplate clutch, especially as regards drag torques, cooling behavior, floating effects and friction coefficient behavior.

[0060] In the context of the present invention, tests and studies have been carried out to determine how an optimum ratio of the lining thickness on one side, in particular the friction lining thickness 53, 54, to the thickness 56, 57 of the carrier plate 55 can be optimized. In the process, it has been found that a ratio of the friction lining thickness 53, 54 to the carrier plate thickness 56, 57 of 0.25 to 0.85 is the optimum. In specific applications, this ratio makes it possible to ensure that a double clutch can be implemented in an available installation space. Depending on the number of plates, it is possible, by maintaining the optimum ratio, to save installation space totaling several millimeters.

[0061] A detail of a carrier element 60 is illustrated in plan view and in section in FIGS. 4 and 5. The carrier element 60 is a carrier plate of the kind denoted by 55 in FIG. 3, for example. To illustrate friction lining grooving, friction lining pieces 61 to 66; 71 to 74 and 80 are mounted on the carrier element 60. The friction lining pieces 61 to 66; 71 to 74 and 80 are preferably firmly connected in a materially integral manner, in particular by adhesive bonding, to the carrier element 60.

[0062] Friction lining pieces 61 to 63 are of substantially diamond-shaped design. Friction lining pieces 64 to 66 are of substantially triangular design. Here, friction lining pieces 61 to 66 are provided with rounded edges.

[0063] Parallel fluid channels are formed between friction lining pieces 61 to 66. The fluid channels are delimited by the carrier element 60 and friction lining pieces 61 to 66 and extend parallel to one another. The fluid channels are also referred to as grooves.

[0064] As regards the groove design, it should in principle be ensured that an adequate flow cross section for the required cooling oil volume flow is formed to enable said cooling oil to flow through the plate pack without flowing past or building up and promoting unwanted floating of the friction linings.

[0065] Various groove designs are shown by way of example in FIG. 4. Friction lining piece 80 is relatively large and is provided with a stamped groove pattern 81, which is referred to as a waffle pattern. Compared with the waffle pattern 81 with large friction lining pieces, which are also referred to as individual pads, in which the waffle pattern is merely stamped, i.e., the waffle grooves have only a small groove depth, a groove design with smaller or narrower friction lining pieces or individual pads is preferable when using very thin friction linings. In this case, overstamping does not necessarily have to take place since the individual pads already have a sufficiently small area and, in terms of their depth, the intermediate regions/grooves always extend as far as the carrier element 60.

[0066] Thus, the flow cross section of the oil can be maintained despite the relatively thin lining, advantageously while simultaneously keeping the proportion accounted for by grooves unchanged. The proportion accounted for by grooves designates the proportion of the total annular area of the friction linings which has grooves or which does not come into contact with the steel plate.

[0067] Since the surface pressure at the friction contact between the friction lining and the steel plates cannot be increased arbitrarily, the proportion accounted for by grooves must be approximately maintained, even in the case of relatively thin friction linings. Otherwise, an unwanted temperature increase at the friction contact would be the result or it would be necessary to enlarge the annular surface, which, in turn, would entail disadvantages in respect of the radial installation space.

[0068] The groove pattern formed by friction lining pieces 61 to 66 is also referred to as a rain tire pattern. This rain tire pattern has proven advantageous in combination with the claimed ratio of the friction lining thickness to the carrier plate thickness of 0.25 to 0.85.

[0069] As an alternative, a groove pattern with the narrower friction lining pieces 70 to 74 has proven advantageous. In this case, the profile of the grooving or of the pads or friction lining pieces 71 to 74 can also deviate from the radially outward direction and can slope, for example.

[0070] The slope relative to the radial direction may be dependent on a direction of rotation of the plates. By means of the appropriate slope, oil can also be distributed selectively in the circumferential direction in order to achieve an improved cooling performance by means of a larger surface over which flow occurs.

[0071] Various illustrative embodiments of friction linings 90; 110; 130; 140; 160 for a friction plate of the kind illustrated in FIG. 3 and denoted by 33 are illustrated in FIGS. 6 to 10. The friction lining has the form of a circular ring with an internal radius and an external radius. The carrier element (55 in FIG. 3) of the friction plate (33 in FIG. 3) can have the same friction lining 90; 110; 130; 140; 160 on each of the two sides. However, it is also possible for different friction linings 90; 110; 130; 140; 160 to be arranged on the sides of the carrier element (55 in FIG. 3).

[0072] The different friction linings 90; 110; 130; 140; 160 are subdivided over their entire circumference into annular sectors 91 to 95. Annular sectors 96, 97 with three dots indicate that the arrangement of the annular sectors 91 to 95 which is shown in FIGS. 6 to 10 is continued over the entire circumference of the friction lining 90; 110; 130; 140; 160.

[0073] Annular sectors 91 to 95 all have the same shape and the same size. A radially extending groove 101, 102, 103, 104 is arranged between each of two annular sectors 91, 92; 92, 93; 93, 94; 94, 95. The grooves 101 to 104 extend as far as the carrier element (55 in FIG. 3).

[0074] Capital letters A, B, A, B, A in FIGS. 6 to 9 are used to indicate that the annular sectors 91 to 95 have different groove patterns alternately in the circumferential direction. Thus, any desired groove pattern or groove design or lining design A and B can be combined.

[0075] In the case of the friction lining 110 illustrated in FIG. 7, the annular sectors 91, 93, 95 have groove pattern A. In FIG. 7, groove pattern or groove design A is formed in each case by three friction lining pieces 111, 112, 113. Friction lining pieces 111 to 113 are configured and arranged in such a way that the groove pattern 114 obtained has grooves which extend as far as the carrier element or carrier plate (55 in FIG. 3). The groove pattern 114 is also referred to as a rain tire design.

[0076] Annular sectors 92, 94 each include just one friction lining piece or pad 115 with a stamped groove pattern 116. The stamped groove pattern 116 can also be referred to as a micro-waffle design. The grooves in groove pattern 116 are only stamped and do not extend as far as the carrier element.

[0077] In the case of the friction lining 130 illustrated in FIG. 8, the groove pattern 116 from FIG. 7 is combined with a groove pattern 136 stamped in each case into a friction lining piece 135. The groove pattern 136 is also referred to as a waffle design. Waffle design 136 includes significantly larger rectangles than the micro-waffle design 116.

[0078] In the case of the friction lining 140 illustrated in FIG. 9, the rain tire design 114 from FIG. 7 is combined with a groove pattern 145 in annular sectors 92, 94. Groove pattern 145 is formed by friction lining pieces 141 to 144, which have substantially the shape of annular sectors but have only a small extent in the circumferential direction. A radial groove is in each case left between respective pairs of friction lining pieces 141, 142; 142, 143; 143, 144. Like the radial grooves 101, 102 and 103, 104 adjacent to annular sectors 92 and 94, the radial grooves extend as far as the carrier element.

[0079] FIG. 10 indicates that the annular sectors 91, 92; 93, 94; etc. can also have the same paired groove patterns A, A; B, B. Groove pattern 114 or 116 can be used for groove pattern A, for example. Groove pattern 136 or 145 can be used for groove pattern B, for example.

[0080] The friction linings 90; 110; 130; 140; 160 have a lining thickness of 0.5 or 0.8 millimeters, for example. Each friction lining 90; 110; 130; 140; 160 includes at least four annular sectors 91 to 95. A maximum number of the annular sectors 91 to 95 depends on the radius, especially the internal radius, of the friction linings 90; 110; 130; 140; 160. The annular sectors 91 to 95 advantageously have an extent of at least ten millimeters in the circumferential direction.

REFERENCE LABELS

[0081] 1 multiplate clutch

[0082] 2 multiplate clutch

[0083] 3 hub

[0084] 4 hub

[0085] 5 input part

[0086] 6 bearing device

[0087] 7 bearing device

[0088] 8 outer plate carrier

[0089] 9 bearing device

[0090] 10 double clutch

[0091] 11 inner plate carrier

[0092] 12 inner plate carrier

[0093] 13 axis of rotation

[0094] 15 supporting element

[0095] 16 actuation element

[0096] 17 spring element

[0097] 18 actuation element

[0098] 19 spring element

[0099] 21 arrow

[0100] 22 arrow

[0101] 23 actuation bearing

[0102] 24 actuation bearing

[0103] 31 outer plate

[0104] 32 outer plate

[0105] 33 friction plate

[0106] 41 outer plate

[0107] 42 outer plate

[0108] 43 friction plate

[0109] 50 carrier element

[0110] 51 friction lining

[0111] 52 friction lining

[0112] 53 arrow

[0113] 54 arrow

[0114] 55 carrier plate

[0115] 56 arrow

[0116] 57 arrow

[0117] 60 carrier element

[0118] 61 friction lining piece

[0119] 62 friction lining piece

[0120] 63 friction lining piece

[0121] 64 friction lining piece

[0122] 65 friction lining piece

[0123] 66 friction lining piece

[0124] 71 friction lining piece

[0125] 72 friction lining piece

[0126] 73 friction lining piece

[0127] 74 friction lining piece

[0128] 80 friction lining piece

[0129] 81 groove pattern

[0130] 90 friction lining

[0131] 91 annular sector

[0132] 92 annular sector

[0133] 93 annular sector

[0134] 94 annular sector

[0135] 95 annular sector

[0136] 101 groove

[0137] 102 groove

[0138] 103 groove

[0139] 104 groove

[0140] 110 friction lining

[0141] 111 friction lining piece

[0142] 112 friction lining piece

[0143] 113 friction lining piece

[0144] 114 groove pattern

[0145] 115 friction lining piece

[0146] 116 groove pattern

[0147] 130 friction lining

[0148] 135 friction lining piece

[0149] 136 groove pattern

[0150] 140 friction lining

[0151] 141 friction lining piece

[0152] 142 friction lining piece

[0153] 143 friction lining piece

[0154] 144 friction lining piece

[0155] 145 groove pattern

[0156] 160 friction lining