WO2022171224A1

WO2022171224A1 - Friction lamella with a groove pattern formed by a friction lining pad

Info

Publication number: WO2022171224A1
Application number: PCT/DE2021/100929
Authority: WO
Inventors: Benjamin Baerwald; Christian DENDA
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2021-02-11
Filing date: 2021-11-24
Publication date: 2022-08-18
Also published as: JP2024500531A

Abstract

The invention relates to a trapezoidal friction lining pad (11, 12) with embossed grooves (40) for a friction lamella (19). A friction lamella (19) has a carrier lamella (18) and a plurality of trapezoidal friction lining pads (11, 12). A groove pattern (10) comprising segmentation grooves (9, 13) and embossed grooves (40) is formed by means of the carrier lamella (18) and the friction lining pads (11, 12).

Description

FRICTION DISC WITH A GROOVE PATTERN FORMED BY FRICTION PADS

The invention relates to a groove pattern for friction plates with the features according to the preamble of claim 1.

Grooves or groove patterns - referred to in this document as pad geometry - are used to cool the lamellae by oil flow even when the switching elements are closed. They cut through the oil film and thereby stabilize the coefficient of friction. This creates the desired friction behavior when shifting. The idling behavior is improved and the drag torque is reduced.

The scope of the invention:

Wet-running multi-plate clutches and brakes are widely used in conventional powershift transmissions, in new hybrid modules in highly stressed drive trains or in switchable e-axles, and they represent high-performance, highly stressed components. The demands for lower CO2 emissions and improved efficiency of drive trains in motor vehicle applications are of great importance. In addition to reducing load-independent losses in switching elements, the thermal load and adequate cooling must be taken into account. The groove pattern of the friction plate plays a central role in the area of tension between friction characteristics, heat management and efficiency. (see Fig. 1)

WO 2016 180 540 A1 discloses annular wet-running friction linings with a first set of grooves made up of straight grooves which connect the inner circumference and the outer circumference and do not intersect.

US 2009 0 211 867 A1 discloses annular wet-running friction linings with a first set of grooves which connect the inner circumference and the outer circumference and form the trapezoidal friction lining pads which form the annular friction lining, and a second set of grooves made up of embossed grooves. US 3972400 A1 discloses annular wet-running friction linings with a first groove set of radial and straight-line grooves and a second groove set of non-radial and straight-line grooves connecting the inner circumference and the outer circumference.

The invention is based on the object of minimizing the drag losses in friction discs by means of a suitable groove pattern (cf. FIG. 2) and improving cooling (cf. FIG. 7).

The object is achieved by a groove pattern with the features according to claim 1.

The groove pattern for friction plates according to the invention therefore provides that the groove pattern is formed by means of friction lining pads and the friction lining pads have a trapezoidal shape, characterized in that each friction lining pad has embossed grooves.

The course of the embossed grooves towards each other forms a waffle-shaped structure.

The course of the embossed grooves towards each other forms a common waffle-shaped structure over all pads.

In this way, the drag torque is further reduced.

The friction lining pads preferably have the shape of isosceles trapezoids. The trapezoidal friction lining pads are attached to a carrier plate, for example a carrier plate. The carrier plate essentially has the shape of a circular ring disk. Gearing is provided radially on the inside of the carrier plate, which serves to create a non-rotatable connection with a plate carrier. Advantageously, an edge on the carrier plate remains free of friction lining pads radially on the inside and radially on the outside. In this way, tolerances in the size and/or shape of the friction lining pads can be compensated for when they are fastened to the carrier disk. In addition, the friction lining pads are advantageously evenly spaced from one another in the circumferential direction. However, the trapezoidal friction lining pads are advantageously designed with their respective longer base sides alternating radially inwards and radially outwards. directed. The distances between the friction lining pads in the circumferential direction result in grooves between the friction lining pads. These grooves are referred to below as segmentation grooves. The segmentation grooves extend obliquely to a radial direction due to the trapezoidal shape of the friction lining pads. Due to the alternating orientation of the friction lining pads, the segmentation grooves are also arranged at different angles to the radial direction.

A preferred exemplary embodiment of the groove pattern is characterized in that the groove pattern comprises at least eight friction lining pads arranged as a ring, with a segmentation groove being arranged in each case in a circumferential direction between two adjacent friction lining pads. The segmentation grooves are limited in the circumferential direction by the adjacent friction lining pads. The segmentation grooves are open radially on the inside and radially on the outside. The segmentation grooves are limited in their groove depth by the carrier lamella.

A further preferred exemplary embodiment of the groove pattern is characterized in that the embossed grooves in the friction lining pads have a greater groove width than the segmentation grooves between the friction lining pads. The width of the segmentation grooves is defined relative to one another by the distance between the trapezoidal friction lining pads. The smaller groove width of the segmentation grooves is particularly advantageous because the segmentation grooves preferably have a greater groove depth than the embossed grooves. An embossing depth of the embossed grooves is at most fifty percent of a thickness of the friction lining pads. This has proven to be advantageous with regard to the manufacture and fastening of the friction lining pads.

Another preferred embodiment of the groove pattern is characterized in that the ratio of the area of the segmentation grooves to the area of the embossed grooves is at least one to two, preferably between one to two and one to four. The area of the embossed grooves is at least twice the area of the segmentation grooves. In this way, the drag torque can be effectively reduced. A further preferred exemplary embodiment of the groove pattern is characterized in that pad interior angles in pad corners have a degree of between sixty and one hundred and twenty degrees. A pad interior angle is included in each pad corner. Due to the trapezoidal shape of the friction lining pads, each friction lining pad includes two circumferentially adjacent interior angles that are greater than ninety degrees and two circumferentially adjacent interior angles that are less than ninety degrees.

A further preferred exemplary embodiment of the groove pattern is characterized in that all of the pad corners are rounded along their peripheral contour. This has proven advantageous with regard to the flow around the friction lining pads.

Another preferred exemplary embodiment of the groove pattern is characterized in that the radii of curvature in the pad corners are greater than or equal to one millimeter. This has proven to be sufficient with regard to the flow around the friction lining pads.

A further preferred exemplary embodiment of the groove pattern is characterized in that the friction lining pads each have an X embossing, with an intersection point of the X embossing being arranged centrally in relation to the respective friction lining pad. The X embossing, also known as cross embossing, is symmetrical in itself. The X embossing comprises four central grooves arranged in a cross shape, which can also be referred to as main grooves. In addition, depending on the size of the friction lining pads, the X embossing includes further grooves on the side of the four main grooves, which can also be referred to as edge grooves or secondary grooves. Depending on the size of the friction lining pads, these edge grooves or secondary grooves are also only partially formed.

Another preferred embodiment of the groove pattern is characterized in that the X embossing has groove angles of between ninety and one hundred degrees radially inside and radially outside, with the X embossing having groove angles of between eighty and ninety degrees and one hundred degrees in opposite circumferential directions, respectively. Radially inside and radially outside can also be referred to as bottom and top with regard to the groove angle. Analogously, the opposite circumferential directions, with regard to the groove angle, are also referred to as right and left. A degree of between eighty-five and ninety-five degrees is particularly preferred for the groove angles in the opposite circumferential directions, ie for the right and left groove angles.

Another preferred embodiment of the groove pattern is characterized in that the friction lining pads have widths and heights that have a width-to-height ratio that is less than 2.5 for each friction lining pad. The width-to-height ratio of the friction lining pads is preferably between 3.1 and 2.4. This width-to-height ratio is advantageous for both directions of rotation in which the friction plates can be twisted relative to steel plates.

A further preferred exemplary embodiment of the groove pattern is characterized in that the friction lining pads are aligned with tooth gaps in an internal toothing of a carrier plate. In this way, direct oiling of the friction lining pads, in particular the X embossing of the friction lining pads, is made possible in a simple manner.

A further preferred exemplary embodiment of the groove pattern is characterized in that the segmentation angles of the friction lining pads are between one hundred and forty and one hundred and sixty degrees. The segmentation angle indicates how obliquely the segmentation grooves are arranged relative to a radial line that runs through the central point of intersection of the X embossing of the respective friction lining pad.

Another preferred embodiment of the groove pattern is characterized in that all friction lining pads have the same shape and size. This has also proven to be advantageous with regard to the production and assembly of the friction lining pads. The term same shape and size includes manufacturing tolerances.

The invention further relates to a friction lining pad for a groove pattern as described above. The friction lining pads can be traded separately.

Further advantages and advantageous configurations of the invention are the subject matter of the following figures and their description. They show in detail:

Figure 1 Connections: air intake and drag torque

Figure 2 Objective and Improvements

Figure 3 groove design according to the invention

FIG. 4 dimensioning of the groove design according to the invention

FIG. 5 dimensioning of the groove design according to the invention

FIG. 6 dimensioning of the groove design according to the invention

FIG. 7 Oil course in the groove design according to the invention

FIG. 8 dimensioning of the groove design according to the invention

FIG. 9 dimensioning of the groove design according to the invention

• Segmentation of the pads: at least 8 pads arranged as a ring, with a segmentation groove in between (Fig. 6 (6), Fig. 9)

• Pad angle (Fig, 4 (1)) between 60 and 120 degrees (details see Fig. 8 and Fig.

9)

• Pad outer edges rounded along the circumference, preferably >= 1 mm (Fig. 5

(2))

• Symmetrical cross embossing (X embossing) on trapezoidal pad (Fig. 7). Intersection of the X embossing in the middle of the base pad.

• Pad width (3) to height (4) ratio less than 2.5 (preferably from 2.1 to 2.4) (Fig. 5)

• Width of the embossing, i.e. the embossing groove (5) > width of the pad spacing, i.e. the segmentation groove (6) (Fig. 6)

• X-groove angle (Fig. 6): top / bottom (7): between 90 and 110 degrees, right / left (8): between 90 and 100 degrees (preferably 85 and 95 degrees)

• Alignment of teeth to pad: direct oiling of the pad (Fig. 7 (9), Fig. 9)

• Angle of segmentation (Fig. 9) between 140 and 160 degrees > angle of overstamping (7), (8) (X-groove angle, Fig. 6)

• Ratio of the segmentation (area of the segmentation grooves (6)) to the embossing (area of the embossed grooves (5)) (FIG. 6): at least 1:2, preferably between 1:2 and 1:4 Unlike in WO 2016 180 540 A1, Fig. 11, Fig. 12, there is no annular groove in the groove design according to the invention, resulting in the following advantages:

• Improvement of the friction power input and utilization of the thermal mass, which is missing due to an existing annular groove.

• Improvement of the wear behavior of the lining material.

• Rotationally symmetrical trapezoidal waffle results in an even cooling and lubrication.

• Improvement of the coefficient of friction through more effective oil drainage.

In contrast to US 2007 0000 747 A1, the groove design according to the invention has the same groove width of the segmentation grooves between the pads in order to compensate for the conveying effect or damming effect of the oil in internally oiled friction systems.

There are also no purely radial grooves in the groove design according to the invention, in order to reduce lubricating wedge effects on the groove edges and to reduce hydroplaning when shifting (opening/closing) the friction system.

The groove design according to the invention can be described as a trapezoidal waffle design, comprising trapezoidal pads with X-groove waffle embossing:

The embossing leads to a reduction in the fibrousness on the punched pads (reduction of drag torque)

Ratio of segmentation (segmentation grooves) and overstamping (stamping grooves): number of divisions in a ratio of at least 1:2, preferably between 1:2 and 1:4. An optimum between cooling and de-oiling of the friction system can thus be found (cf. FIG. 7). The cooling oil can be guided optimally to the surface of the counter-friction disc (cf. FIG. 7) by means of a coordinated embossing, and the convective heat transfer can thus be improved (cooling). At the same time, when open, the slats can be separated (by means of the lubricating oil) and the intake of air can be improved (lower drag torque).

FIG. 1 illustrates how air is drawn in 26 by a conveyed volume flow 24 when this exceeds the supplied volume flow 25 . From this limit, the degree of gap filling 26 decreases and the lubricating gap between the lamellae contains air. Above this limit, a supplied volume flow contains 25 air. In FIG. 2 below, one can see that the intake of air 26 occurs at a maximum drag torque 27 . FIG. 2 shows how, with the claimed friction part 15, a displacement of the air intake 28 to a low speed in a drag torque curve 30 is reached. The conveying effect of the cooling and/or lubricating medium can be improved by the groove pattern shown in FIG.

A groove pattern 10 according to the invention, which is also referred to as a groove design, is shown in FIGS. The groove pattern 10 includes friction lining pads 11 , 12 which are arranged on a carrier plate 18 . The carrier disk 18 with the friction lining pads 11, 12 is referred to as the friction disk 19.

The friction lining pads 11, 12 all have a trapezoidal shape with rounded corners. In the circumferential direction, the friction lining pads 11, 12 are spaced apart from one another in such a way that a segment groove 9, 13, 14 is created between two adjacent friction lining pads 11, 12. The depth of the segmentation grooves 9 , 13 , 14 is limited by the carrier lamella 18 .

FIG. 3 shows that a short base side of the trapezoidal friction lining pad 11 is arranged radially on the inside. A short base side of the trapezoidal friction lining pads 12 is arranged radially on the outside. The result is that the segmentation grooves 9, 13, as can be seen in FIG. 3, are each arranged obliquely to a radial in opposite directions.

In addition, one can see in FIG. The friction lining lagpads 11, 12 are each associated with a tooth gap 16.

The friction lining pads 11, 12 are also equipped with an X embossing 40. In FIG. 3 one can see that the friction lining pad 12 with its X embossing 40 is aligned with the tooth gap 16 of the internal toothing 17 of the carrier plate 18 .

In FIG. 4 one can see that the friction lining pad 12 with the X embossing 40 comprises a total of eight embossed grooves 41 to 48 . The embossed grooves 41 to 44 are arranged in the shape of a cross and represent an X with a center 49 defined by a circle in the Center of the friction lining pads 12 is indicated. The friction lining pad 12 is symmetrical in relation to a centrally arranged axis of symmetry 50 .

The embossed grooves 41 to 44 are also referred to as main grooves or central grooves. The embossed grooves 45 to 48 are also referred to as marginal grooves or secondary grooves. The edge grooves 45 and 46 are not always completely formed due to the trapezoidal shape of the friction lining pad 12 .

A pad inner angle 1 is assigned to each pad corner of the friction lining pad 12 . On egg ner carrier plate 18 at least eight trapezoidal friction lining pads 11, 12 are preferably attached. The inner pad angles 1 measure between sixty and one hundred and twenty degrees.

A width of the friction lining pad 12 is indicated by a double arrow 3 in FIG. A height of the friction lining pad 12 is indicated by a double arrow 4 in FIG. All corners of the friction lining pad 12 are provided with radii of curvature 2 .

A groove width of the embossed groove 41 in the friction lining pad 12 is indicated by a double arrow 5 in FIG. A groove width of the segment menting groove 13 is indicated by a double arrow 6 . All segmentation grooves 9, 13 preferably have essentially the same groove width 6. The embossed grooves 41 to 48 also preferably have essentially the same groove width 5.

A groove angle between the embossed grooves 43 and 44 is indicated by a double arrow 7 . The groove angle 7 is also referred to as the radially inner or lower groove angle 7 be. Similarly, the groove angle 7 between the embossed grooves 41 and 42 is referred to as the radially outer or upper groove angle 7 .

A double arrow 8 indicates a groove angle on the left in FIG. 6 between the embossed grooves 41 and 43 . The analogous groove angle between the embossed grooves 42 and 44 is referred to as the right groove angle. The left groove angle 8 and the right groove angle 7 are also referred to as circumferentially opposite groove angles. In FIG. 7, reference numbers 31 to 34 are assigned to the four pad corners. All pad corners 31 to 34 of the friction lining pad 12 are rounded. The longer base side of the friction lining pad 12 is aligned centrally with the tooth gap 16 of the internal toothing 17 of the carrier plate 18 .

Entering cooling medium, in particular oil, is indicated by an arrow 59 . The oil 59 is supplied, for example, via an external toothing of a Lamel lenträgers, not shown. Arrows 51 to 54 indicate in FIG. 7 how the oil 59 supplied radially inside is distributed in the X embossing 40 of the friction lining pad 12 . The oil 59 then escapes radially on the outside of the friction plate 19 .

In FIG. 8, double arrows 61 to 64 and 71 to 74 indicate inner pad angles of the friction pads 11 and 12. The inner pad angles 61 to 64 have degrees of 61.5; 119.8; 119.8; 61.5. The inner pad angles 71 to 74 of the friction lining pad 12 have degrees of 115.3; 163.4; 163.4 and 115.3.

Segmentation angles are indicated by double arrows 77, 78 in FIG. The segmentation angle 77 is 147.5 degrees and is enclosed between dash-dotted lines 76 and 79. The dot-dash line 76 corresponds to an axis of symmetry of the friction lining pad 11, which runs in the radial direction. The dot-dash line 79 extends along a leg of the friction lining pad 11 on the left in Figure 9.

The segmentation angle 78 is 157.5 degrees and is enclosed between a dash-dot line 50 and a dash-dot line 80 . The dash-dotted line 50 corresponds to an axis of symmetry of the friction lining pad 12, which runs in the radial direction. The dot-dash line 80 runs on a leg of the friction lining pad 12 on the right in Figure 9. Reference character list

1 pad inner angle

2 curve radii

3 widths

4 heights

5 groove width

6 groove width

7 groove angle

8 groove angles

9 segmentation groove

10 groove patterns

11 friction lining pad

12 friction lining pad

13 segmentation groove

14 segmentation groove

15 teeth

16 tooth gap

17 internal teeth

18 support slat

19 friction plate

20 x axis

21 y-axis

22 y-axis

23 y-axis

24 funded volume flow

25 supplied volume flow

26 air intake

27 drag torque

28 air intake

30 drag torque curve

31 pad corner

32 pad corner 33 pad corner

34 pad corner

40 X embossing

41 embossed groove

42 embossed groove

43 embossed groove

44 embossed groove

45 embossed groove

46 embossed groove

47 embossed groove

48 embossed groove

49 center

50 axis of symmetry

51 arrow

52 arrow

53 arrow

54 arrow

57 arrow

58 arrow

59 arrow

61 pad interior angles

62 pad interior angles

63 pad interior angles

64 pad interior angles

71 pad interior angles

72 pad interior angles

73 pad interior angles

74 pad interior angles

76 axis of symmetry

77 segmentation angles

78 segmentation angles

79 line

80 line

Claims

patent claims

1. Groove pattern (10) for friction plates (19), the groove pattern (10) being formed by means of friction lining pads (11,12) and the friction lining pads (11,12) having a trapezoidal shape, characterized in that each friction lining pad ( 11,12) has embossed grooves (41-48).

2. Groove pattern according to claim 1, characterized in that the groove pattern (10) comprises at least eight friction lining pads (11, 12) arranged as a ring, with a segmentation groove (9, 13, 14) is arranged.

3. Groove pattern according to claim 2, characterized in that the embossed grooves (41-48) in the friction lining pads (11,12) have a greater groove width (5) than the segmentation grooves (8,13,14).

4. Groove pattern according to claim 2 or 3, characterized in that a ratio of the area of the segmentation grooves (9,13,14) to the area of the embossed grooves (41-48) is at least 1 to 2, preferably between 1 to 2 and 1 to 4, is.

5. Groove pattern according to one of the preceding claims, characterized in that the friction lining pads (11, 12) each have an X embossing (40), with an intersection point (49) of the X embossing (40), based on the respective friction lining pad (11,12), are arranged in the middle.

6. Groove pattern according to Claim 5, characterized in that the X embossing (40) has a groove angle (7) radially inside and radially outside between ninety and one hundred and ten degrees, the X embossing (40) having groove angles (8th ) between eighty and ninety and one hundred degrees, respectively.

7. Groove pattern according to one of the preceding claims, characterized in that the friction lining pads (11,12) have widths (3) and fleas (4) which have a width (3) to fleas (4) ratio which is for each friction lining pad (11.12) is less than 2.5.

8. Groove pattern according to one of the preceding claims, characterized in that the friction lining pads (11, 12) are aligned with tooth gaps (16) of an internal toothing (17) of a carrier plate (18).

9. Groove pattern according to one of the preceding claims, marked thereby, that the segmentation angle (77,78) of the friction lining pads (11,12) is between 140 and

be 160 degrees.

10. Friction lining pad (11,12) for a groove pattern (10) according to any one of the preceding claims.