Friction disk having a groove pattern formed by a friction lining pad

Abstract

The present invention relates to a rectangular friction lining pad (11-13) for a friction disc (19) having a substantially rhomboid-like or parallelogram-shaped design, which friction lining pad (11-13) is a friction surface having an inner diameter (83) and an outer diameter (84) and has, in a fixed state on a carrier disc (18), two pad grooves (8) defined by the friction lining pad (11-13) and an embossed groove (9) which meet at an intersection point (81, 82) located inside the friction surface. The friction disc (19) comprises a carrier disc (18) and a number of friction lining pads (11-13) of this type, preferably of the same design and size. A groove pattern with the pad grooves (8) and the embossed grooves (9) is formed by the carrier disc (18) and the friction lining pads (11-13).

Description

Technical Field

[0001] The present invention relates to a groove pattern for a friction disk having the features described in the preamble of claim 1.

Background Art

[0002] Grooves or groove patterns, also referred to herein as pad shapes, are used to cool the disk by oil flow even when the switching element is in the closed state. The grooves or groove patterns cut through the oil film, thereby stabilizing the friction value. Thereby, the desired friction behavior is realized during switching. The idling behavior is improved and the drag torque is reduced.

[0003] Scope of application of the present invention: Wet multi-plate clutches and brakes are for a wide range of applications in conventional power shift transmissions, new hybrid modules for high-load drive trains, or switchable e-axles, in which case they form high-performance components that meet high requirements. In automotive applications, the requirements for reducing CO2 emissions and improving the efficiency of the drive train are extremely important. In addition to reducing load-dependent losses in the switching element, attention must be paid to the heat load and sufficient cooling. When the friction characteristics, heat balance, and efficiency affect each other, the groove pattern of the friction disk plays a central role (see FIG. 1).

[0004] International Publication No. 2016 / 180540 (A1) discloses an annular wet friction lining having a first set of grooves that connect the inner peripheral portion and the outer peripheral portion, extend linearly without extending or intersecting in the radial direction. U.S. Patent No. 6,293,382 (B1) has an additional second set of grooves, each groove of which connects two adjacent grooves of the first set of grooves.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is, in the case of a friction disk, to minimize the drag loss by means of an appropriate groove pattern (see FIG. 2) and to optimize the cooling capacity (see FIG. 4).

Means for Solving the Problem

[0006] This problem is solved by a groove pattern having the features described in claim 1.

[0007] Therefore, the groove pattern according to the present invention for a friction disk is contemplated such that the groove pattern is formed using friction lining pads, the friction lining pads have a diamond-like shape, and each friction lining pad has a grooved impression.

[0008] In this way, the drag torque is further reduced.

[0009] The diamond-shaped friction lining pads are attached to a carrier disk, for example, a carrier plate. The carrier disk substantially has an annular disk shape. On the inner or outer radial side of the carrier disk, there are provided toothing portions used to provide a non-rotatable connection with the disk carrier. On the inner and outer radial sides, advantageously, the edges of the carrier disk remain independent of the friction lining pads. Thus, when attaching the carrier disk, tolerances in the size and / or shape of the friction lining pads can be corrected. Further, the friction lining pads are advantageously uniformly spaced from each other in the circumferential direction. The spacing between the friction lining pads in the circumferential direction results in grooves between the friction lining pads. Such grooves are hereinafter referred to as pad grooves. The pad grooves extend obliquely with respect to the radial direction due to the diamond-like shape of the friction lining pads. Depending on the rotational direction of twisting the friction disk, in this case, the steel disk rotates faster than the friction disk, resulting in either a locking action or a pumping action. Both actions will be described in detail in the following description of the drawings. The oil flow can be optimized from the inner radial side to the outer radial side between the steel disk and the friction disk by the embossed grooves in the friction lining pads, especially taking into account the cooling capacity. Particularly advantageously, the locking action resulting from the locking effect can be varied most effectively by the interaction between the diamond-like friction lining pads, the pad grooves, and the embossed grooves.

[0010] The friction lining pad is a friction surface having an inner diameter and an outer diameter. The pad grooves are formed by the spacing between the friction lining pads. The friction surface has the shape of an annular surface having an inner diameter and an outer diameter. In that case, since the friction surface is defined by the friction lining pads, it may have size deviations not only related to the inner diameter but also related to the outer diameter in terms of tolerances. According to a main aspect of the present invention, the two intersections of the embossed grooves of each friction lining pad having the pad grooves defined by the friction lining pads are both necessarily inside the friction surface, and thus are arranged radially between the inner diameter and the outer diameter of the friction surface.

[0011] According to a preferred embodiment of this groove pattern, the inner pad angle at the pad corner has an angle of 40 to 145 degrees. Each pad corner includes an inner pad angle. Based on the rhomboid-like shape of the friction lining pad, each friction lining pad includes two inner opposing angles greater than 90 degrees and two inner opposing angles less than 90 degrees. The specified size range is related to this. Two of the inner angles are preferably 40 to 50 degrees. The other two inner angles are preferably 125 to 145 degrees.

[0012] In a further preferred embodiment of this groove pattern, it is characterized in that all pad corners are rounded along the peripheral contour. This has been shown to be advantageous in view of the flow around the friction lining pad.

[0013] In a further preferred embodiment of this groove pattern, it is characterized in that the radius of curvature of the pad corner is 1 millimeter or more. This has been shown to be sufficient in view of the flow around the friction lining pad.

[0014] In a further preferred embodiment of this groove pattern, the friction lining pad is characterized in that, for each friction lining pad, it has a width and a height with a ratio of width to height of less than 2. The ratio of the width to the height of the friction lining pad is preferably between 1.5 and 1.7. This ratio of width to height is advantageously applied in both directions in which the friction disc can be twisted.

[0015] In a further preferred embodiment of this groove pattern, one pad groove with a groove width is arranged between two adjacent friction lining pads, and the groove width is smaller than the groove width of the embossed groove of the friction lining pad. The width of the pad groove is relatively mutually defined by the spacing of the rhomboid-like friction lining pads. The smaller groove width of the pad groove is particularly advantageous because the pad groove preferably has a greater groove depth than the embossed groove.

[0016] In a further preferred embodiment of the present groove pattern, the branch angle between the pad groove and the embossed groove is characterized by being 90 to 100 degrees. A particularly preferred branch angle between the pad groove and the embossed groove is 90.4 degrees. The presented angle range results in the embossed groove extending substantially intersecting the pad groove. This has been shown to be extremely effective taking into account the desired influence on the oil flow in the required groove pattern.

[0017] In a further preferred embodiment of the present groove pattern, the embossing depth of the embossed groove corresponds to a maximum of 50 percent of the thickness of the friction lining pad. This has been shown to be advantageous taking into account the manufacture and attachment of the friction lining pad.

[0018] In a further preferred embodiment of the present groove pattern, all the friction lining pads have the same shape and size. This has also been shown to be advantageous taking into account the manufacture and attachment of the friction lining pads. The term same shape and size includes manufacturing tolerances.

[0019] The present invention further relates to a friction lining pad for the groove pattern described above. The friction lining pads can be handled individually.

[0020] Further advantages and advantageous embodiments of the present invention are the subject of the following drawings and their description.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0022] · The angle (1) in FIG. 6 is 40 to 145 degrees (for details, refer to FIG. 9). · The outer edge of the pad is rounded along the circumference, preferably 1 mm or more (refer to FIG. 7(2)). · The double-row design considering the central molding results in substantially the same pad surface in a triangular shape for the inner row and the outer row, and a base shape without considering the molding. The pad is formed as a rhombus. · The ratio of the width (3) of the pad to the height (4) is less than 2 (preferably 1.5 to 1.7) (refer to FIG. 7). · The width of the molding (5) is wider than the width of the groove (6) (refer to FIG. 8). · The ratio of the groove angle to the molding angle (7) is 90 to 100 degrees, preferably 90.4 degrees (refer to FIG. 8).

[0023] - Optimization of the manufacturing quality by the optimized pad shape. - Improvement of the drawability and end quality by, for example, groove molding and reduction of the drag torque when the friction device is in the open state. - Robust wear characteristics over the service life of the pad ends and pad corners. By maintaining the end shape (slight rounding (1)), strong and consistent hydrodynamic characteristics (wedge action) and, thus, stable friction characteristics are provided. The application cost of control is reduced. - Rapid removal of the oil film according to a further preferred embodiment of the invention, wherein the branch angle (7) is 90 to 100°, preferably 90.4°. - Depending on the angular position of the groove, an oil conveying action (FIG. 3A) or a locking action (FIG. 3B) corresponding to the relative rotational direction of the steel disk facing the friction disk can be realized (directivity). The cooling capacity (see FIG. 4) can be varied according to the application depending on the relative rotational direction between the friction disk and the steel disk. This inflow can be arbitrarily formed by the pad-type pressing portion ("pressed groove" in FIG. 5) (see FIG. 8: pressing depth, width (5), angle (7)) and optimized for each application.

[0024] In FIG. 1, three Cartesian coordinate graphs are shown superimposed vertically. On the x-axis 20, one rotational speed each is depicted in appropriate units when the wet multi-plate clutch 1 having the friction portion 15 is operating. On the y-axis 21, the volume flow rate is depicted in appropriate units. On the y-axis 22, the clearance volume efficiency is depicted in appropriate units. On the y-axis 23, the drag torque is depicted in appropriate units.

[0025] In FIG. 1, it is specifically shown how the air introduction 26 is performed by the conveyed volume flow rate 24 when the conveyed volume flow rate 24 exceeds the supplied volume flow rate 25. When this limit is exceeded, the clearance volume efficiency 26 decreases and the lubrication clearance contains air. When this limit is exceeded, the supplied volume flow rate 25 contains air. Below FIG. 2, it is shown that the air introduction 26 occurs in the case of the maximum drag torque 27.

[0026] In FIG. 2, it is shown how the displacement of air introduction 28 to a low rotational speed is achieved in the drag torque curve 30 by the friction part 15 to which stress is applied. The groove pattern illustrated in FIG. 3 can improve the conveyance action of the cooling medium and / or the lubricating medium.

[0027] FIG. 3 includes FIGS. 3A and 3B. In FIGS. 3A and 3B, a groove pattern 10 according to the present invention, also referred to as a groove design, is illustrated. The groove pattern 10 includes friction lining pads 11 to 13; 14 to 16 disposed on the carrier disk 18. The carrier disk 18 having the friction lining pads 11 to 13; 14 to 16 is referred to as a friction disk 19.

[0028] All of the friction lining pads 11 to 13; 14 to 16 have a diamond-like shape with rounded corners. The friction lining pads 11 to 13; 14 to 16 are circumferentially spaced apart from each other such that one pad groove 8 is formed between two adjacent friction lining pads 12, 13; 14, 15, respectively. The pad groove 8 is limited to the depth of the carrier disk 18. The pad groove 8 extends obliquely with respect to the radial direction.

[0029] Furthermore, each of the friction lining pads 11 to 13; 14 to 16 has one embossed groove 9. The embossed groove 9 extends intersecting the pad groove 8. Furthermore, the pad groove 8 has a groove depth larger than that of the embossed groove 9. The groove depth of the embossed groove 9 is up to 50 percent of the thickness of the friction lining pads 11 to 13; 14 to 16. The groove depth of the pad groove 8 corresponds to the thickness of the friction lining pads 11 to 13; 14 to 16.

[0030] In a multi-plate clutch, a plurality of friction discs 19 with steel discs are arranged within a disc package. In FIGS. 3A and 3B, the rotational directions during operation of the friction discs 19 are indicated by arrows 60; 70. In that case, the condition applies that the assigned steel discs rotate faster than the respectively assigned friction discs 19. Forces acting during operation are indicated by arrows 61 - 64; 71 - 74, which result from an oil flow from the radially inner side to the radially outer side between the friction discs 19 and the steel discs.

[0031] Arrows 61; 71 specifically indicate centrifugal force. Arrows 62; 72 specifically indicate the flow due to the pad grooves 8, which, depending on the pad inner angles and the rotational directions 60; 70, result in the forces indicated by arrows 62; 72 due to the diamond-like shapes of the friction lining pads 11 - 13; 14 - 16.

[0032] In FIGS. 3A and 3B, the forces brought about by the relative movement between the steel discs and the friction discs 19 are indicated by arrows 63; 73. The forces resulting from forces 61 - 63; 71 - 73 are indicated by arrows 64; 74.

[0033] In FIG. 3A, when the friction discs 19 rotate slower than the assigned steel discs in the rotational direction 60, the locking action brought about by the friction lining pads 11 - 13 is specifically shown. In FIG. 3B, when the friction discs 19 rotate slower than the assigned steel discs in the rotational direction 70, the pumping action brought about by the friction lining pads 14 - 16 is specifically shown.

[0034] In FIG. 4, a bar graph consisting of the y-axis 40 and bars 41 - 44 is shown. On the y-axis 40, the cooling capacity is depicted in kilowatts. The bars 41 - 44 represent the cooling capacity for different volumes of flow rates that can be achieved with the groove pattern 10 of FIGS. 3A and 3B.

[0035] Bars 41 and 42 specifically indicate a relatively low volume flow rate of oil. Bars 43, 44 rather specifically indicate a high volume flow rate. In that case, in FIG. 3 B bars 41, 43 are assigned to the pumping action. Bars 42, 44 are assigned to the locking action in FIG. 3 A as shown.

[0036] The pumping action results in an increase in cooling capacity not only for low but also for high volume flow rates. However, as shown in FIG. 4, the cooling capacity does not change as much for high volume flow rates as it does for low volume flow rates. The locking action can be relaxed or varied depending on the application, by the specification of the embossed grooves, or by the cross-sectional area of the embossed grooves, i.e., the width and depth. The larger the cross-sectional area, the greater the oil outflow through the embossed grooves.

[0037] In FIG. 5, it is shown that the friction lining pads 11 - 13 are rounded at their pad corners 31 - 34. In FIG. 7, a radius of curvature of 2 is shown and is substantially equal at all pad corners 31 - 34. The radius of curvature 2 is preferably 1 millimeter or more.

[0038] In FIG. 6, the inner pad angle 1 of the friction lining 12 is indicated by double arrows. The inner pad angle 1 is 40 - 145 degrees. By arranging the embossed groove 9 centrally within the friction lining pad 12, a multi-row groove design with the same pad surface on the radially inner and outer sides is provided. The same pad surface has one triangular shape each, based on the diamond-like shape of the friction lining pad 12.

[0039] In FIG. 7, the width of the friction lining pad 12 is indicated by double arrow 3. The height of the friction lining pad 12 is indicated by double arrow 4. The ratio of the width 3 to the height 4 is preferably less than 2 for all friction lining pads. The ratio of the width 3 to the height 4 is preferably 1.5 - 1.7 for all friction lining pads 11 - 13; 14 - 16 of the groove pattern 10.

[0040] In FIGS. 6 and 7, auxiliary lines are drawn on the friction lining pad 12 for dimensioning. There is a gap, partially, between the auxiliary lines and the friction lining pad 12. This gap specifically indicates the tolerance that may exist due to the manufacturing conditions of the friction lining pad 12.

[0041] In FIG. 8, the groove width of the die-pressed groove 9 is indicated by the double arrow 5. The groove width of the pad groove 8 between the friction lining pads 12 and 13 is indicated by the double arrow 6. The branch angle between the pad groove 8 and the die-pressed groove 9 is indicated by the double arrow 7.

[0042] The branch angle 7 between the pad groove 8 and the die-pressed groove 9 within the complete groove pattern 10 is preferably 90 to 100 degrees, and preferably 90.4 degrees.

[0043] In FIG. 9, the pad inner angles of the friction lining pad 12 are indicated by the double arrows 51 to 54. The angles of the pad inner angles 51 to 54 are 132; 44.5; 142; 41.6 in the order of description.

[0044] In FIG. 10, the friction disk 19 described in FIG. 3A is shown with auxiliary lines, and it is specifically shown that the friction lining pads 11 to 13 form the friction surface 80. The friction surface 80 is defined radially inward by the inner diameter 83 and radially outward by the outer diameter 84. Here, tolerances may occur due to manufacturing conditions.

[0045] However, substantially, the intersections 81, 82 of the die-pressed groove 9 of the friction lining pad 12 and the two pad grooves 8 and 78 defined by the friction lining pad 12 are arranged inside the friction surface 80.

Description of Reference Numerals

[0046] 1 Pad inner angle 2 Radius of curvature 3 Width 4 Height 5 Groove width 6 Groove width 7 Divergence angle 8 Pad groove 9 Molded groove 10 Groove pattern 11 Friction lining pad 12 Friction lining pad 13 Friction lining pad 14 Friction lining pad 15 Friction lining pad 16 Friction lining pad 18 Carrier disk 19 Friction disk 20 x-axis 21 y-axis 22 y-axis 23 y-axis 24 Conveyed volume flow rate 25 Supplied volume flow rate 26 Air introduction 27 Drag torque 28 Air introduction 30 Drag torque curve 31 Pad corner 32 Pad corner 33 Pad corner 34 Pad corner 40 y-axis 41 Rod 42 Rod 43 Rod 44 Rod 51 Pad inner angle 52 Pad inner angle 53 Pad inner angle 54 Pad inner angle 60 Rotation direction 61 Arrow 62 Arrow 63 Arrow 64 Arrow 70 Rotation direction 71 Arrow 72 Arrow 73 Arrow 74 Arrow 78 Pad groove 80 Friction surface 81 First intersection point 82 Second intersection point 83 Inner diameter 84 Outer diameter

Claims

**Claim 1**: A friction disk having a groove pattern (10), wherein the groove pattern (10) is formed using a plurality of friction lining pads (11 - 13; 14 - 16), the friction lining pads (11 - 13; 14 - 16) have a diamond - like shape with two opposite sides perpendicular to the radial direction, the plurality of friction lining pads (11 - 13; 14 - 16) are arranged spaced apart from each other in the circumferential direction, and constitute a friction surface (80) having the shape of an annular surface with an inner diameter (83) and an outer diameter (84). In the friction disk, each of the friction lining pads (11 - 13; 14 - 16) has a grooved - pressed groove (9), and the grooved - pressed groove (9) intersects at a first intersection point (81) and a second intersection point (82) both arranged inside the friction surface (80) with two pad grooves (8; 78) defined by each of the friction lining pads. Among the pad interior angles (1) of the pad corner portions, which are the corner portions of the friction lining pads (11 - 13; 14 - 16), two opposite interior angles greater than 90 degrees have an angle between 125 and 145 degrees. The branch angle (7) between the pad groove (8; 78) and the grooved - pressed groove (9) is an angle between 90 and 100 degrees, characterized by a friction disk. **Claim 2** The friction disk according to claim 1, characterized in that all of the pad corner portions are rounded along their peripheral contours. **Claim 3** The friction disk according to claim 1 or 2, characterized in that the radius of curvature (2) of the pad corner portion is 1 millimeter or more. **Claim 4**: The ratio of the height (4), which is the radial length, to the width (3), which is the circumferential length, of each of the friction lining pads (11 - 16) is less than 2, characterized by a friction disk according to any one of claims 1 to 3. **Claim 5** The friction disk according to any one of claims 1 to 4, characterized in that between two adjacent friction lining pads (11 - 16), one pad groove (8; 78) having a groove width (5) is arranged, and the groove width (5) is smaller than the groove width (6) of the grooved - pressed groove (9) of the friction lining pads (11 - 16). **Claim 6** The embossing depth of the embossed groove (9) corresponds to a maximum of 50 percent of the thickness of the friction lining pads (11 to 16), the friction disk according to any one of claims 1 to 5.

7. All of the friction lining pads (11 to 16) have the same shape and the same size, the friction disk according to any one of claims 1 to 6.

8. A friction lining pad (11 to 16) for a friction disk according to any one of claims 1 to 7.

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