WET MULTI-PLATE CLUTCH

Abstract

A wet multi-plate clutch includes a plate carrier with a pair of fluid passage openings and a friction plate rotationally fixed and axially displaceable relative to the plate carrier. The friction plate has a carrier element and a pair friction pads fastened to the carrier element and delimiting a groove. The groove includes a groove geometrical center line. The groove geometrical center line may extend radially through a one of the pair of fluid passage openings, or it may extend radially between the pair of fluid passage openings. If the groove geometrical center line extend radially between the pair of fluid passage openings, one of the pair of friction pads may include a pad geometrical center line extending along a radial extent through a one of the pair of fluid passage openings.

Claims

1. A wet multi-plate clutch, comprising clutch plates connected to a plate carrier for conjoint rotation while being displaceable in an axial direction, the plate carrier having fluid passage openings, wherein at least one of the clutch plates, or each of the clutch plates, is designed as a friction plate with a groove delimited by friction pads, wherein: at least one geometrical center line of the groove extends in the plate carrier along a radial extent through one of the fluid passage openings; or the groove extends along a radial extent through a center between two immediately adjacent fluid passage openings, and a geometrical center line of one of the friction pads extends along a radial extent through one of the two immediately adjacent fluid passage openings.

2. (canceled)

3. The wet multi-plate clutch of claim 1, wherein the groove is delimited by friction pads fastened to a carrier element.

4. The wet multi-plate clutch of claim 1, wherein all of the fluid passage openings are arranged in tooth tip regions of a toothing of the plate carrier.

5. The wet multi-plate clutch of claim 1, wherein, in addition to fluid passage openings in tooth tip regions of a toothing of the plate carrier, the plate carrier has further fluid passage openings in tooth base regions of the plate carrier.

6. The wet multi-plate clutch according to claim 5, wherein the friction plate has further grooves which extend along radial extents through the fluid passage openings in the tooth base regions of the toothing of the plate carrier.

7. The wet multi-plate clutch according to claim 5, wherein the friction plate has further embossed grooves which extend along radial extents through the fluid passage openings in the tooth base regions of the toothing of the plate carrier.

8. The wet multi-plate clutch according to claim 1, wherein the friction plate has embossed grooves which are formed in the friction pads.

9. The wet multi-plate clutch of claim 1, wherein the friction pads have the shape of trapezoids.

10. A clutch plate for a wet multi-plate clutch according to claim 1.

11. A wet multi-plate clutch, comprising: a plate carrier comprising a pair of fluid passage openings; and a friction plate rotationally fixed and axially displaceable relative to the plate carrier, the friction plate comprising: a carrier element; and a pair friction pads fastened to the carrier element and delimiting a groove, the groove comprising a groove geometrical center line: extending radially through a one of the pair of fluid passage openings; or extending radially between the pair of fluid passage openings.

12. The wet multi-plate clutch of claim 11, wherein: the groove geometrical center line extends radially between the pair of fluid passage openings; and one of the pair of friction pads comprises a pad geometrical center line extending along a radial extent through a one of the pair of fluid passage openings.

13. The wet multi-plate clutch of claim 11 further comprising: a plurality of pairs of friction pads; and a plurality of grooves delimited by the plurality of pairs of friction pads.

14. The wet multi-plate clutch of claim 11, wherein: the plate carrier comprises a toothing; the toothing comprises tooth tip regions and tooth base regions; and the pair of fluid passage openings are arranged in respective tooth tip regions; or the pair of fluid passage openings are arranged in respective tooth base regions.

15. The wet multi-plate clutch of claim 11, wherein the pair of friction pads comprise respective embossed grooves formed therein.

16. The wet multi-plate clutch of claim 11, wherein the pair of friction pads each have a trapezoidal shape.

17. A wet multi-plate clutch, comprising: a plate carrier comprising a toothing, the toothing comprising: a tooth tip region comprising a first fluid passage opening arranged therein; and a tooth base region comprising a second fluid passage opening arranged therein; and a friction plate, rotationally fixed and axially displaceable relative to the toothing, the friction plate comprising: a carrier element; and a pair of friction pads fastened to the carrier element and delimiting a groove, wherein: the groove comprises a groove geometrical center line extending radially through the first fluid passage opening; and a one of the pair of friction pads comprises an embossed groove comprising an embossed groove geometrical center line extending radially through the second fluid passage opening.

18. The wet multi-plate clutch of claim 17, wherein the pair of friction pads each have a trapezoidal shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Further configurations of the present disclosure are the subject of the following figures and the description thereof. Specifically:

[0024] FIG. 1 shows a clutch plate designed as a friction plate having friction pads which are fastened to a carrier element which is connected for conjoint rotation to a plate carrier designed as an inner plate carrier, according to a first exemplary embodiment;

[0025] FIG. 2 shows a variant of the first exemplary embodiment having a plate carrier designed as an outer plate carrier;

[0026] FIG. 3 shows a view similar to that in FIG. 1 according to a second exemplary embodiment;

[0027] FIG. 4 shows a view similar to that in FIG. 2 according to a second exemplary embodiment;

[0028] FIGS. 5 to 8 show enlarged representations of FIGS. 1 to 4 to illustrate further details of the exemplary embodiments;

[0029] FIG. 9 shows three Cartesian coordinate diagrams to illustrate relationships between an air intake and a drag torque; and

[0030] FIG. 10 shows two further Cartesian coordinate diagrams to illustrate the task and the improvements which are achieved with the exemplary embodiments described.

DETAILED DESCRIPTION

[0031] A wet multi-plate clutch includes two plate carriers, one of which is designed as an outer plate carrier and the other as an inner plate carrier, and of which only one plate carrier is shown in each of the figures. A wet multi-plate clutch also includes a plate pack with clutch plates. The clutch plates are designed alternately as friction plates and as steel plates. Inner plate carrier and outer plate carrier are equipped with a toothing. The toothing alternately has a tooth tip region and a tooth base region. In the following, the radially outer toothing regions are referred to as tooth tip regions both in the case of the outer plate carriers and also in the inner plate carriers, while the radially inner toothing regions are referred to as tooth base regions.

[0032] Within the scope of this document, only the regions 1 between the friction pads that are free of friction linings are explicitly referred to and addressed as grooves 1. In addition to these grooves 1, embossed grooves are also shown in the figures. These are referred to and addressed as embossed grooves in the context of this document.

[0033] In the plate carriers, in the inner plate carrier, which is also referred to as the inner multi-plate carrier and/or in the outer plate carrier, which is also referred to as the multi-outer plate carrier, there are fluid passage openings (oil bores 2) distributed over the circumference at various axial positions, through which a fluid got into a friction space. A space that may be designed as an annular space between the two plate carriers is referred to as a friction space. Because of the axial displacement, the axial position of the, or some of the, clutch plates changes when the multi-plate clutch is actuated. The clutch plates essentially have a rectangular profile. Depending on the axial position of the friction plates, the friction lining of one friction plate or several friction plates may be located above or in front of one of the oil bores 2 (fluid passage openings) and thus impede the fluid supply into the friction space. In this case, only a restricted flow cross-section is available for the fluid, which impairs the flow of the fluid and generally increases the flow resistance for the fluid.

[0034] The arrangement of the grooves allows the profile of the friction plate to be fluidically improved in such a way that the flow resistance is reduced and thus the supply of fluid to the multi-plate clutch is improved and the drag torque is reduced.

[0035] Due to the arrangement of the grooves, the profile of the friction plate can be improved in terms of flow in such a way that the flow resistance is increased and thus an increase in the cooling effect is achieved by deflecting the oil flow.

[0036] FIG. 1 and FIG. 2 show the arrangement of the grooves to be radial to the oil bore in the plate carrier. FIG. 1 shows this using the example of an inner plate carrier and FIG. 2 using the example of an outer plate carrier.

Reduction of the Drag Torque Through Optimal De-Oiling of the Friction System Through Direct Oil Supply

[0037] Internal toothing (FIG. 1): Optimum radial flow through the friction system and improvement in de-oiling/displacement of the air intake towards lower rotational speeds (reduction of drag torque). The bores are shown here in the tooth tip region of the internal toothing. With the same arrangement of the grooves, namely radial to the oil bore, the bores can alternatively also be provided in each case at the tooth base region of the internal toothing. In the case of additional bores in the tooth base region, either no further grooves are provided or, alternatively, further grooves or embossed grooves are provided to be radial to the additional bores in the tooth base region.

[0038] External toothing (FIG. 2): Optimum radial flow through the friction system and improved de-oiling on the outer plate carrier. Reduction of the accumulation of the cooling oil on the outer diameter and reduction of the shear in the oil (reduction of drag torque). The bores are shown here in the tooth tip region of the external toothing. With the same arrangement of the grooves, namely radial to the oil bore, the bores can alternatively also be provided in each case on the tooth base region of the external toothing. In the case of additional bores in the tooth base region, either no further grooves are provided or, alternatively, further grooves or embossed grooves are provided to be radial to the additional bores in the tooth base region.

[0039] FIG. 3 and FIG. 4 show the arrangement of the grooves offset to the oil bore in the plate carrier:

Increasing the Cooling Effect by Redirecting the Oil Flow in the Friction System

[0040] Internal toothing (FIG. 3): Redirecting the cooling oil volume flow leads to better distribution of the cooling oil in the friction system and a larger contact area for convective heat transfer (cooling oil/steel fins).

[0041] External toothing (FIG. 4): Redirecting the cooling oil volume flow leads to a damming effect on the cooling oil. This leads to improved wetting of the steel laminations by the cooling oil and thus leads to an improved cooling effect.

[0042] Alignment of the Groove Relative to the Bore in the Plate Carrier with Regard to Oil Removal and Drag Torque

[0043] FIG. 5: Grooving/segmentation 1 of the friction lining of the friction plates is adapted to the toothing pitch of the plate carrier: Alignment of the groove/segmentation 1 is oriented to be radial in the direction of the oil bores 2 of the inner plate carrier. Grooving can be done, for example, by embossing, milling, or punching (segmentation). The number of holes can differ from the number of grooves/segmentation of the friction lining. The diameter of the oil bore 2 and the width of the groove can vary.

[0044] FIG. 6 is analogous to FIG. 5, but having oil bores 2 in the outer plate carrier: Alignment of the groove/segmentation 1 is oriented to be radial in the direction of the oil bores 2 of the outer plate carrier.

Alignment of the Groove Relative to the Hole in the Plate Carrier with Regard to Cooling

[0045] FIG. 7: Grooving/segmentation 1 of the friction lining of the friction plates is adapted to the toothing pitch of the plate carrier: Radial alignment of the groove/segmentation 1 in the circumferential direction offset from the radial through oil bores 2 of the inner plate carrier. Grooving can be done, for example, by embossing, milling, or punching (segmentation). The number of holes can differ from the number of grooves/segmentation of the friction lining. Oil bore diameter and groove width may vary.

[0046] FIG. 8 is analogous to FIG. 7, but having oil bores 2 in the outer plate carrier: Radial alignment of the groove/segmentation 1 in the circumferential direction offset from the radial through oil bores 2 of the outer plate carrier.

General Drag Torque, Oil Removal, Air Intake

[0047] FIG. 9 shows the causal relationships.

[0048] FIG. 10 shows the goal/improvement:

Shifting the Onset of the Air Intake to Lower Rotational Speeds

[0049] Oil removal/air intake is improved by the radial arrangement of the groove in a radial extent to the bore in the plate carrier. FIG. 9 illustrates how an air intake 26 is effected by a conveyed volume flow 24 if this exceeds the supplied volume flow 25. From this limit, the gap fill level 26 decreases and the lubricating gap between the plates contains air. Above this limit, a supplied volume flow 25 contains air. The bottom of FIG. 10 shows that the air intake 26 occurs at a maximum drag torque 27.

[0050] The air intake is improved by the radial arrangement of the groove in a radial extent to the bore in the plate carrier. In FIG. 10, it is shown how a shift of the air intake 28 to a low rotational speed is achieved in a drag torque curve 30. The conveying effect of the cooling and/or lubricating medium can be improved by the groove/segmentation 1 shown in FIGS. 1 through 8.

[0051] In the FIGS. 1, 2 and 3, 4 two exemplary embodiments for the design of a clutch plate 4, 5; 6, 7 for a wet multi-plate clutch 10 are each depicted in a top view of a section of the clutch plate 4, 5; 6, 7.

[0052] The clutch plates 4 and 6 in FIGS. 1 and 3 are hooked with an internal toothing into a complementary external toothing of a plate carrier 8 designed as an internal plate carrier. The clutch plates 5 and 7 in FIGS. 2 and 4 are suspended with an external toothing in a complementary internal toothing of a plate carrier 9 designed as an external plate carrier.

[0053] The internal toothing of the clutch plates 4, 6 is provided on a carrier element 15. The carrier element 15 is, for example, a carrier sheet onto which trapezoidal friction pads 11 to 14 are glued. The outer toothings of the clutch plates 5, 7 in FIGS. 2 and 4 each provided on a carrier element 55 are glued to the friction pads 51, 52. Like the friction pads 11 to 14 in FIGS. 1 and 3, the friction pads 51, 52 each have the shape of a trapezium, the longer base side of which is arranged to be radially inward on the respective carrier element 15; 55.

[0054] Arrows in FIGS. 1 to 4 indicate how a fluid, e.g., oil, is guided through a friction space for cooling and/or lubrication, which friction space in the multi-plate clutch 10 essentially has the shape of an annular space. In FIGS. 1 and 2, radial arrows illustrate how the fluid passes unhindered radially through a groove 1 between the friction pads 11 to 14; 51, 52. In FIGS. 3 and 4, branched arrows indicate how the fluid entering radially on the inside flows through the groove 1 to bypass the friction pads 11 to 14; 51, 52.

[0055] In FIGS. 5 to 8, the exemplary embodiments of FIGS. 1 to 4 are enlarged and shown with additional reference numbers. As in FIGS. 1 to 4, 2 designates fluid passage openings through which the fluid is supplied radially on the inside through the respective plate carrier 8, 9. Through the groove 1, the fluid supplied radially on the inside is guided differently through the friction space, which is limited by the respective clutch plate 4; 5; 6; 7.

[0056] In the case of the clutch plates 4 and 6 illustrated in FIGS. 5 and 7, the groove 1 comprises a groove 16 which is delimited in each case by two adjacent friction pads 12, 13. In FIG. 5, the groove 16 is arranged in a radial extent of the fluid passage opening 2 of the plate carrier 8. In FIG. 7, the groove 16 is offset in the circumferential direction between two fluid passage openings 2.

[0057] In FIGS. 6 and 8, the groove 1 comprises a groove 56 which is delimited by the two friction pads 51 and 52. In FIG. 6, the groove 56 is arranged on a common radial line with the fluid passage opening 2 of the plate carrier 9. In FIG. 8, the groove 56 is arranged to be offset in the circumferential direction between two fluid passage openings 2 of the plate carrier 9.

[0058] The friction pads 11 to 14 and 51, 52 are equipped with embossed grooves 18, 19; 58, 59. The embossed grooves 18, 19; 58, 59 extend parallel to each other on each pad. The individual friction pads 11 to 14 and 51, 52 are each aligned to be radial.

[0059] In FIG. 7, the embossed groove 18 is arranged on a common radial line with the fluid passage opening 2 of the plate carrier 8. The embossed groove 19 is assigned to a fluid passage opening 2 of the plate carrier 8 that is adjacent in the circumferential direction. In FIGS. 5 and 7, a toothing of the carrier element 15 designed as an internal toothing is denoted by 17. With this toothing 17, the carrier element 15 is hooked into a toothing 50 of the plate carrier 8, designed as a complementary external toothing. Through the intermeshing of the toothings 17 and 50 is created a connection for conjoint rotation between the plate carrier 8 and the respective clutch plate 4; 6.

[0060] In FIGS. 6, 8, the carrier element 55 is equipped with a toothing 57 designed as an external toothing, which engages in a complementary toothing 60 of the plate carrier 9. A connection for conjoint rotation is also created here between the carrier element 55 and the plate carrier 9.

[0061] A geometrical center line 61 illustrates in FIG. 5 that the groove of the groove 1 between the friction pads 12 and 13 extends along a radial extent through the fluid passage opening 2 in the plate carrier 8.

[0062] A geometrical center line 62 illustrates in FIG. 6 that the groove of the groove 1 between the friction pads 51 and 52 extends along a radial extent through the fluid passage opening 2 in the plate carrier 9.

[0063] A geometrical center line 63 of the friction pad 12 is drawn in FIG. 7. Unlike what is shown in FIG. 7, the geometrical center line 63 corresponds to an axis of symmetry of the friction pad 12.

[0064] The geometrical center line 63 or axis of symmetry of the friction pad 12 extends along a radial extent through the fluid passage opening 2 in the plate carrier 8. At the same time, the geometrical center line 63 or axis of symmetry of the friction pad 12 in FIG. 7 coincides with a geometrical center line 63 of the embossed groove 18.

[0065] A geometrical center line 64 is drawn in FIG. 8, which corresponds to an axis of symmetry of the friction pad 51. The geometrical center line 64 or axis of symmetry extends along a radial extent through the fluid passage opening 2 of the plate carrier 9.

REFERENCE NUMERALS

[0066] 1 Grooving [0067] 2 Fluid passage opening [0068] 4 Clutch plate [0069] 5 Clutch plate [0070] 6 Clutch plate [0071] 7 Clutch plate [0072] 8 Plate carriers (inside) [0073] 9 Plate carrier (outside) [0074] 10 Wet multi-plate clutch [0075] 11 Friction pad [0076] 12 Friction pad [0077] 13 Friction pad [0078] 14 Friction pad [0079] 15 Carrier element [0080] 16 Groove [0081] 17 Toothing [0082] 18 Embossed groove [0083] 19 Embossed groove [0084] 20 X-axis [0085] 21 Y-axis [0086] 22 Y-axis [0087] 23 Y-axis [0088] 24 Conveyed volume flow [0089] 25 Supplied volume flow [0090] 26 Air intake [0091] 27 Drag torque [0092] 28 Air intake [0093] 30 Drag torque curve [0094] 50 Toothing [0095] 51 Friction pad [0096] 52 Friction pad [0097] 55 Carrier element [0098] 56 Groove [0099] 57 Toothing [0100] 58 Embossed groove [0101] 59 Embossed groove [0102] 60 Toothing [0103] 61 Geometrical center line [0104] 62 Geometrical center line [0105] 63 Geometrical center line [0106] 64 Geometrical center line