Friction disc having groove pattern formed by friction lining pad

Abstract

The present invention relates to a trapezoidal friction lining pad (11, 12) with embossed grooves (40) for a friction disc (19). The friction disc (19) comprises a carrier disc (18) and a number of trapezoidal friction lining pads (11, 12). A groove pattern (10) including dividing grooves (9, 13) and embossed grooves (40) is formed by the carrier disc (18) and the friction lining pads (11, 12).

Description

[Technical field]

[0001] The present invention relates to a groove pattern for a friction disc having the features according to the preamble of claim 1. [Background technology]

[0002] A groove or groove pattern, also referred to in this document as pad geometry, is used to cool the disk by oil flow even when the switching element is closed. The groove or groove pattern breaks up the oil film and thus stabilizes the friction value. This creates the desired friction behavior during switching. The idling behavior improves and the drag torque is reduced.

[0003] Fields of application of the present invention: Wet multi-plate clutches and brakes are intended for a wide range of applications in conventional powershift transmissions, new hybrid modules in highly loaded drivetrains or switchable e-axles, where they are high-performance components that meet high demands. In automotive applications, the need to reduce CO2 emissions and increase the efficiency of the drivetrain are of crucial importance. Attention must be paid to low load-dependent losses in the switching elements as well as thermal loads and sufficient cooling. Where friction properties, heat balance and efficiency interact, the groove pattern of the friction discs plays a central role. (See Figure 1)

[0004] WO 2016 180 540 A1 discloses an annular wet friction lining comprising a first groove set of non-intersecting, straight-extending grooves connecting an inner periphery and an outer periphery.

[0005] US 2009 0 211 867 (A1) discloses an annular wet friction lining with a first groove set and a second groove set consisting of embossed grooves that join the inner and outer periphery to form a trapezoidal friction lining pad that forms an annular friction lining.

[0006] US Pat. No. 3,972,400 (A1) discloses an annular wet friction lining with a first groove set of radially and linearly extending grooves and a second groove set of non-radially and linearly extending grooves connecting the inner and outer periphery. Summary of the Invention [Problem to be solved by the invention]

[0007] The objective of the present invention is to minimize drag losses (see FIG. 2) and improve cooling (see FIG. 7) in the case of friction discs by means of a suitable groove pattern. [Means for solving the problem]

[0008] This problem is solved by a groove pattern having the features of claim 1.

[0009] The groove pattern according to the invention for a friction disc therefore provides for the groove pattern to be formed using friction lining pads, the friction lining pads having a trapezoidal structure and each friction lining pad having embossed grooves. The paths between the embossed grooves form a honeycomb-like structure. The inter-groove paths of the embossed grooves form a honeycomb-like structure that is common on all pads.

[0010] In this way the drag torque is further reduced.

[0011] The friction lining pads preferably have an isosceles trapezoidal structure. The trapezoidal friction lining pads are attached to a carrier disk, for example a carrier plate. The carrier disk has a substantially annular disk structure. The carrier disk is provided radially inward with toothings, which are used to provide a non-rotatable connection with the disk carrier. Radially inward and radially outward, the edges of the carrier disk preferably remain independent of the friction lining pads. Thus, when attaching the carrier disk, tolerances in the size and / or structure of the friction lining pads can be compensated for. Furthermore, the friction lining pads are preferably uniformly spaced apart from one another in the circumferential direction. However, the trapezoidal friction lining pads are preferably aligned alternately with their respective longer base sides radially inward and radially outward. Due to the spacing of the friction lining pads from one another in the circumferential direction, grooves between the friction lining pads result. These grooves are referred to below as dividing grooves. Due to the trapezoidal structure of the friction lining pads, the dividing grooves run obliquely to the radial direction. Since the friction lining pads are aligned alternately, the dividing grooves are likewise arranged alternately at different inclinations relative to the radial direction.

[0012] A preferred embodiment of the groove pattern is characterized in that the groove pattern comprises at least eight friction lining pads arranged in an annular manner, with one dividing groove being arranged between each pair of circumferentially adjacent friction lining pads. The dividing groove is limited in the circumferential direction by the adjacent friction lining pads. Radially inwardly and radially outwardly, the dividing groove is open. The groove depth of the dividing groove is limited by the carrier disk.

[0013] A further preferred embodiment of the groove pattern is characterized in that the embossed grooves in the friction lining pads have a groove width that is greater than the dividing grooves between the friction lining pads. The dividing groove widths are relatively mutually defined by the spacing of the trapezoidal friction lining pads. The smaller groove width of the dividing grooves is particularly advantageous, since the dividing grooves preferably have a groove depth that is greater than the embossed grooves. The embossed grooves have a maximum embossing depth of 50 percent of the thickness of the friction lining pads. This has been found to be advantageous with a view to the manufacture and installation of the friction lining pads.

[0014] A further preferred embodiment of the groove pattern is characterized in that the ratio of the area of ​​the dividing groove to the area of ​​the embossed groove is at least 1:2, preferably 1:2 to 1:4. The area of ​​the embossed groove is at least twice the area of ​​the dividing groove. Therefore, the drag torque can be effectively reduced.

[0015] A further preferred embodiment of the groove pattern is characterized in that the pad interior angles at the pad ends have an angle of 60 to 120 degrees. Each pad end includes a pad interior angle. Due to the trapezoidal structure of the friction lining pads, each friction lining pad includes two circumferentially adjacent interior angles that are greater than 90 degrees and two circumferentially adjacent interior angles that are less than 90 degrees.

[0016] A further preferred embodiment of the groove pattern is characterized in that all pad edges are rounded along the peripheral contour, which has proven to be advantageous with respect to the peripheral flow of the friction lining pads.

[0017] A further preferred embodiment of the groove pattern is characterized in that the pad ends have a radius of roundness of at least 1 mm, which has been found to be sufficient having regard to the flow around the friction lining pads.

[0018] A further preferred embodiment of the groove pattern is characterized in that the friction lining pads each have one X-shaped embossment, the intersection of which is arranged centrally with respect to the friction lining pad. The X-shaped embossments, also called cross embossments, are symmetrical. The X-shaped embossments include four central grooves arranged in a cross shape, which may also be called main grooves. Furthermore, the X-shaped embossments include further grooves on the side of the four main grooves, which may also be called edge grooves or secondary grooves, depending on the size of the friction lining pad. These edge grooves or secondary grooves are formed even only partially, depending on the size of the friction lining pad.

[0019] A further preferred embodiment of the groove pattern is characterized in that the X-shaped embossments have groove angles of 90-110 degrees radially inward and radially outward, and the X-shaped embossments have groove angles of 80-110 degrees or 90-110 degrees opposite in the circumferential direction. The radially inward and radially outward can also be referred to as lower and upper sides, taking into account the groove angles. Similarly, the opposite circumferential directions can also be referred to as right and left sides, taking into account the groove angles. Particularly preferably, the opposite circumferential groove angles, i.e. right and left groove angles, have angles of 85-95 degrees.

[0020] A further preferred embodiment of the groove pattern is characterized in that the friction lining pads have a width and height such that for each friction lining pad the width to height ratio is less than 2.5. The width to height ratio of the friction lining pads is preferably between 3.1 and 2.4. This width to height ratio advantageously applies in both directions in which the friction disc can twist relative to the steel disc.

[0021] A further preferred embodiment of the groove pattern is characterized in that the friction lining pads are aligned with the tooth grooves of the internal toothing of the carrier disk, thus making direct lubrication of the friction lining pads, in particular the X-shaped depressions of the friction lining pads, possible in a simple manner.

[0022] A further preferred embodiment of the groove pattern is characterized in that the friction lining pads have a split angle of 140 to 160 degrees. The split angle indicates how obliquely the split grooves extending through the central intersection of the X-shaped embossments of each friction lining pad are disposed relative to the radius.

[0023] A further preferred embodiment of the groove pattern is characterized in that all friction lining pads have the same structure and size. This has also proven to be advantageous with a view to the manufacture and installation of the friction lining pads. The term same structure and size includes manufacturing tolerances.

[0024] The invention further relates to a friction lining pad for the groove pattern described above.The friction lining pad can be addressed individually.

[0025] Further advantages and advantageous embodiments of the invention are the subject of the following drawings and their description. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a diagram showing the relationship between air intake and drag torque. [Diagram 2] FIG. 1 is a diagram showing problems and improvements. [Diagram 3] FIG. 1 illustrates a groove design according to the present invention. [Figure 4] FIG. 13 illustrates dimensions of groove designs according to the present invention. [Diagram 5] FIG. 13 illustrates dimensions of groove designs according to the present invention. [Figure 6] FIG. 13 illustrates dimensions of groove designs according to the present invention. [Figure 7] FIG. 13 illustrates oil flow in a groove design according to the present invention. [Figure 8] FIG. 13 illustrates dimensions of groove designs according to the present invention. [Figure 9] FIG. 13 illustrates dimensions of groove designs according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Pad division: At least eight pads are arranged in a ring, with one division groove between each pad (Figure 6 (6) and Figure 9) The pad angle (Figure 4(1)) is 60 to 120 degrees (see Figures 8 and 9 for details) The outer edge of the pad is rounded along the periphery, preferably by 1 mm or more (Figure 5 (2)) A symmetrical cross-shaped section (X-shaped section) is placed on the trapezoidal pad (Fig. 7). The intersection of the X-shaped sections is in the center of the lining pad. The width (3) to height (4) ratio of the pad is less than 2.5 (preferably 2.1 to 2.4) (FIG. 5). The width of the embossed portion, i.e., the embossed groove (5), is greater than the width of the pad spacing, i.e., the dividing groove (6) (Figure 6) X-groove angle (Fig. 6): Upper / lower (7): 90~110 degrees, Right side / left side (8): 90-100 degrees (preferably 85-95 degrees) - Alignment of the gear cutting part with respect to the pad: Direct lubrication to the pad (Fig. 7 (9), Fig. 9) The angle of the dividing section (Figure 9) is 140 to 160 degrees, which is larger than the angle of the overlapping embossing sections (7) and (8) (X-shaped groove angle, Figure 6). Ratio of the dividing portion (area of ​​the dividing groove (6)) to the overlapping embossing portion (area of ​​the embossing groove (5)) (FIG. 6): at least 1:2, preferably 1:2 to 1:4

[0028] Unlike figures 11 and 12 of WO 2016 180 540 A1, in the case of the groove design according to the invention there is no ring groove, which results in the following advantages: Improved friction force application and utilization of thermal mass lost through existing ring grooves. Improved wear properties of lining materials. The rotationally symmetric trapezoidal honeycomb provides uniform cooling and lubrication. Improved friction value build-up due to more effective oil evacuation.

[0029] Unlike US 2007 0000 747(A1), the groove design according to the present invention has split grooves with equal groove width between pads in case of internally lubricated friction systems to compensate for oil transport or stagnation effects.

[0030] Also, in the groove design according to the invention, there are no purely radial grooves in order to reduce the lubricating effect of the groove edges when switching (open / closed) the friction system and thus prevent hydroplaning.

[0031] The groove design according to the present invention may be referred to as a trapezoidal honeycomb design and has a trapezoidal pad with an X-groove honeycomb impression.

[0032] The overlapping die section results in less fibrousness (lower drag torque) in the stamped pad.

[0033] The ratio of the division section (division groove) to the overlapping embossing section (embossing groove):number of divisions is at least 1:2, preferably 1:2 to 1:4. This allows both cooling and de-oiling of the friction system (see FIG. 7). By adjusting the overlapping embossing section, the cooling oil can be appropriately guided to the opposing friction disc (see FIG. 7), thereby improving the convective heat transfer (cooling). At the same time, the separation of the discs (using lubricating oil) can be performed in an open state, improving the air intake (reduced drag torque).

[0034] In Figure 1 it is shown how the delivered volume flow 24 causes air intake 26 when it exceeds the supplied volume flow 25. Above this limit the gap volume efficiency 26 decreases and the lubrication gap contains air. Above this limit the supplied volume flow 25 contains air. In the lower part of Figure 2 it is shown that air intake 26 occurs in the case of maximum drag torque 27.

[0035] In figure 2 it is shown how the stressed friction section 15 achieves a shift in the drag torque curve 30 towards lower speeds of the air intake 28. The groove pattern shown in figure 3 allows for improved transport of the cooling and / or lubricating media.

[0036] In figures 3 to 9 a groove pattern 10 according to the invention, also called groove design, is shown. The groove pattern 10 comprises friction lining pads 11, 12 arranged on a carrier disc 18. The carrier disc 18 with the friction lining pads 11, 12 is called friction disc 19.

[0037] The friction lining pads 11, 12 all have a trapezoidal structure with rounded ends. The friction lining pads 11, 12 are spaced apart from one another in the circumferential direction, so that a dividing groove 9, 13, 14 is formed between each two adjacent friction lining pads 11, 12. The dividing grooves 9, 13, 14 are limited to the depth of the carrier disk 18.

[0038] In Fig. 3, the short base side of the trapezoidal friction lining pad 11 is arranged radially inward. The short base side of the trapezoidal friction lining pad 12 is arranged radially outward. It follows from this that the dividing grooves 9, 13 are arranged obliquely to the radius in opposite directions, as shown in Fig. 3.

[0039] 3, the carrier disk 18 is further shown to have an internal toothing 17 with teeth 15 and tooth spaces 16 between the teeth 15. The friction lining pads 11, 12 are each assigned to a tooth space 16.

[0040] Furthermore, the friction lining pads 11, 12 are provided with an X-shaped depression 40. In Fig. 3, the friction lining pad 12 with its X-shaped depression 40 is shown aligned with the tooth gap 16 of the internal toothing 17 of the carrier disk 18.

[0041] 4, the friction lining pad 12 is shown to include a total of eight embossed grooves 41-48 along with the X-embossed portion 40. The embossed grooves 41-44 are arranged in a cross shape, with the X represented by the center 49, which is indicated by a circle in the center of the friction lining pad 12. The friction lining pad 12 is symmetrical about a centrally located axis of symmetry 50.

[0042] The embossed grooves 41-44 are also referred to as main or central grooves. The embossed grooves 45-48 are also referred to as edge or secondary grooves. The edge grooves 45 and 46 are not always completely formed due to the trapezoidal structure of the friction lining pad 12.

[0043] Each pad end of the friction lining pad 12 is assigned a pad interior angle 1. At least eight trapezoidal friction lining pads 11, 12 are preferably mounted on the carrier disk 18. The angle of the pad interior angle 1 is 60 to 120 degrees.

[0044] In figure 5 the width of the friction lining pad 12 is indicated by a double arrow 3. The height of the friction lining pad 12 is indicated in figure 5 by a double arrow 4. All edges of the friction lining pad 12 are provided with a rounding radius 2.

[0045] In Fig. 6 the groove width of the embossed groove 41 in the friction lining pad 12 is indicated by a double arrow 5. The groove width of the dividing groove 13 is indicated by a double arrow 6. All dividing grooves 9, 13 preferably have substantially the same groove width 6. The embossed grooves 41-48 also preferably have substantially the same groove width 5.

[0046] The groove angle between embossed groove 43 and embossed groove 44 is indicated by double arrow 7. Groove angle 7 is also referred to as radially inner or lower groove angle 7. Similarly, groove angle 7 between embossed groove 41 and embossed groove 42 is also referred to as radially outer or upper groove angle 7.

[0047] The groove angle between embossed groove 41 and embossed groove 43 is indicated on the left side of Figure 6 by double arrow 8. The similar groove angle between embossed groove 42 and embossed groove 44 is referred to as the right side groove angle. Left side groove angle 8 and right side groove angle 7 are also referred to as circumferentially opposed groove angles.

[0048] In Fig. 7, the four pad ends are assigned the reference numbers 31 to 34. All pad ends 31 to 34 of the friction lining pad 12 are rounded. The friction lining pad 12 is aligned with its long base side in the center of the tooth groove 16 of the internal toothing 17 of the carrier disk 18.

[0049] The arrows 59 indicate the inflowing cooling medium, in particular oil. The oil 59 is fed, for example, via the external toothing of a disk carrier (not shown). In FIG. 7, the arrows 51-54 show how the oil 59 fed radially inwards is distributed to the X-shaped impressions 40 of the friction lining pad 12. The oil 59 then flows out radially outwards of the friction disk 19.

[0050] In Fig. 8, the pad interior angles of the friction lining pads 11 and 12 are indicated by double arrows 61-64 and 71-74. The pad interior angles 61-64 are 61.5 degrees, 119.8 degrees, 119.8 degrees, and 61.5 degrees. The pad interior angles 71-74 of the friction lining pad 12 are 115.3 degrees, 163.4 degrees, 163.4 degrees, and 115.3 degrees.

[0051] In Fig. 9, the split angle is indicated by double arrows 77, 78. The split angle 77 is 147.5 degrees and is sandwiched between dashed and dotted lines 76 and 79. The dashed and dotted line 76 coincides with the radially extending axis of symmetry of the friction lining pad 11. The dashed and dotted line 79 extends along the left leg of the friction lining pad 11 in Fig. 9.

[0052] The split angle 78 is 157.5 degrees and is sandwiched between dashed line 50 and dashed line 80. Dashed line 50 coincides with the radially extending axis of symmetry of friction lining pad 12. Dashed line 80 extends tangent to the right leg of friction lining pad 12 in FIG. [Explanation of symbols]

[0053] 1 Pad inner angle 2 Roundness radius 3 Width 4 Height 5 Groove width 6 Groove width 7 Groove angle 8 Groove angle 9 Dividing groove 10 Groove Pattern 11 Friction lining pad 12 Friction Lining Pad 13 Dividing groove 14 Dividing groove 15 teeth 16 Tooth space 17 Internal teeth 18 Carrier disc 19 Friction Disc 20x axis 21 y-axis 22 y-axis 23 y-axis 24 Volume flow rate delivered 25 Volume flow rate delivered 26 Air Intake 27 Drag Torque 28 Air Intake 30 Drag torque curve 31 Pad end 32 Pad end 33 Pad end 34 Pad end 40 X-shaped press section 41 Embossed grooves 42 Embossed grooves 43 Embossed grooves 44 Embossed grooves 45 Embossed grooves 46 Embossed grooves 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 inner angle 62 Pad inner angle 63 Pad inner angle 64 Pad Inner Angle 71 Pad inner angle 72 Pad inner angle 73 Pad inner angle 74 Pad Inner Angle 76 Axis of Symmetry 77 Division angle 78 division angle 79 line 80 lines

Claims

1. A groove pattern (10) for a friction disc (19), said groove pattern (10) being formed using friction lining pads (11, 12), said friction lining pads (11, 12) having a trapezoidal structure, in the groove pattern (10), each friction lining pad (11, 12) having embossed grooves (41-48), The groove pattern (10) comprises at least eight trapezoidal friction lining pads (11, 12) arranged in a ring, the friction lining pads (11, 12) being arranged in a circumferential direction with the longer base sides of the trapezoids aligned alternately radially inward and radially outward, one dividing groove (9, 13, 14) being arranged between each two adjacent friction lining pads (11, 12), the embossed grooves (41-48) in the friction lining pads (11, 12) have a groove width (5) larger than the dividing grooves (8, 13, 14), the friction lining pads (11, 12) each have one X-shaped embossment (40), and an intersection (49) of the X-shaped embossment (40) is arranged centrally with respect to each friction lining pad (11, 12).

2. A groove pattern according to claim 1, characterized in that the ratio of the area of ​​the dividing grooves (9, 13, 14) to the area of ​​the embossed grooves (41-48) is between 1:2 and 1:

4.

3. The groove pattern according to claim 1 or 2, characterized in that the X-shaped embossments (40) have groove angles (7) of 90 to 110 degrees on the radially inner side and the radially outer side, and the X-shaped embossments (40) have groove angles (8) of 80 to 110 degrees or 90 to 110 degrees on opposite sides in the circumferential direction.

4. 4. A groove pattern according to claim 1, wherein the friction lining pads (11, 12) have a width (3) and a height (4) such that for each friction lining pad (11, 12) the ratio of the width (3) to the height (4) is less than 2.

5.

5. A groove pattern according to any one of claims 1 to 4, characterized in that the friction lining pads (11, 12) are aligned with the tooth spaces (16) of the internal toothing (17) of the carrier disc (18).

6. A groove pattern according to any one of claims 1 to 5, characterized in that the split angle (77, 78) of the friction lining pads (11, 12) is between 140 and 160 degrees.

7. Friction lining pads (11, 12) for a groove pattern (10) according to any one of claims 1 to 6.

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