Groove structure for a friction plate

Abstract

The invention relates to a groove structure (10) for a friction plate, wherein the groove structure (10) is formed by means of friction linings (11, 12) and the friction linings (11, 12) have a trapezoidal design. The invention is characterized in that each friction lining (11, 12) has an embossed groove.

Description

Technical Field

[0001] This invention relates to a groove structure for a friction plate. Background Technology

[0002] A groove or groove structure—also referred to as a pad geometry within the scope of this document—is used to cool the oil flow through the fins even when the shift element is closed. The groove or groove structure breaks up the oil film, thereby stabilizing the friction value. This achieves the desired frictional performance during shifting, improves idling performance, and reduces drag torque.

[0003] Application areas of this invention: Wet plate clutches and brakes are widely used in traditional power-shift transmissions, new hybrid modules in high-load powertrains, or switchable E-axles, and are high-performance, high-load components. The requirements for lower CO2 emissions and improvements in powertrain efficiency are of great significance in automotive applications. In addition to reducing load-independent losses in shifting elements, thermal load and adequate cooling must also be considered. The groove structure of the friction plates plays a crucial role in the conflict zone of frictional characteristics, thermal balance, and efficiency. (See also...) Figure 1 ) WO 2016 180 540 A1 discloses an annular wet friction liner having a first set of grooves consisting of linearly extending grooves that connect an inner circumference and an outer circumference without intersecting.

[0004] US 2009 0 211 867 A1 discloses an annular wet friction liner having a first set of grooves and a second set of grooves formed by embossing grooves, the friction liner connecting an inner circumference and an outer circumference to form a trapezoidal friction pad, the friction pad forming an annular friction liner.

[0005] US 3,972,400 A1 discloses an annular wet friction liner having a first group of grooves consisting of radially and linearly extending grooves and a second group of grooves consisting of non-radially and linearly extending grooves connecting an inner circumference and an outer circumference. Summary of the Invention

[0006] The purpose of this invention is to minimize drag loss by using a suitable groove structure in the friction pad (see [link]). Figure 2 ), and improved cooling (see Figure 7 ).

[0007] Therefore, according to the invention, a groove structure for a friction pad is proposed, the groove structure being formed by means of a friction pad, and the friction pad having a trapezoidal shape, characterized in that each friction pad has an embossed groove.

[0008] The extension of the embossing grooves forms a waffle-shaped structure.

[0009] The embossing grooves extend from one another to form a common waffle-shaped structure on all the pads.

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

[0011] The friction pads preferably have an isosceles trapezoidal shape. The trapezoidal friction pads are fastened to a support plate, such as a support substrate. The support plate is essentially shaped like a circular disc. Toothed portions are provided on the support plate radially inward, providing a torsional connection with the support element. Advantageously, the edges of the support plate remain free of friction pads radially inward and radially outward. Therefore, tolerances in the dimensions and / or shape of the friction pads can be compensated for when fastened to the support plate. Furthermore, the friction pads are advantageously spaced evenly from each other in the circumferential direction. However, the trapezoidal friction pads are advantageously oriented alternately radially inward and radially outward with their correspondingly longer base sides. Grooves between the friction pads are formed by the spacing between them in the circumferential direction. These grooves are referred to below as dividing grooves. The dividing grooves extend radially at an inclination due to the trapezoidal shape of the friction pads. Due to the alternating orientation of the friction pads, the dividing grooves are also alternately arranged at an inclination in the radial direction.

[0012] A preferred embodiment of the groove structure is characterized in that the groove structure includes at least eight friction pads arranged in rings, wherein a dividing groove is provided between each pair of adjacent friction pads in the circumferential direction. The dividing grooves are defined by adjacent friction pads in the circumferential direction. The dividing grooves are open in both the radially inward and radially outward directions. The groove depth of the dividing grooves is limited by a bearing plate.

[0013] Another preferred embodiment of the groove structure is characterized in that the embossed groove in the friction pad has a larger groove width compared to the dividing groove between the friction pads. The width of the dividing groove is defined by the spacing between the trapezoidal friction pads relative to each other. The smaller groove width of the dividing groove is therefore particularly advantageous because the dividing groove preferably has a larger groove depth compared to the embossed groove. The embossing depth of the embossed groove is at most fifty percent of the thickness of the friction pad. This proves advantageous in the production and fastening of the friction pad.

[0014] Another preferred embodiment of the groove structure is characterized in that the ratio of the area of ​​the dividing groove to the area of ​​the imprinting groove is at least 1:2, preferably between 1:2 and 1:4. The area of ​​the imprinting groove is at least twice the size of the area of ​​the dividing groove. Therefore, the dragging torque can be effectively reduced.

[0015] Another preferred embodiment of the groove structure is characterized in that the interior angles of the pads in the corner portions have a degree between 60 and 120 degrees. Interior angles are formed in each corner portion. Due to the trapezoidal shape of the friction pads, each friction pad includes two adjacent interior angles in the circumferential direction with a degree greater than 90 degrees and two adjacent interior angles in the circumferential direction with a degree less than 90 degrees.

[0016] Another preferred embodiment of the groove structure is characterized in that all pad corners are rounded along their circumferential contour. This proves advantageous in terms of flow around the friction pad.

[0017] Another preferred embodiment of the groove structure is characterized in that the rounding radius at the corner of the pad is greater than or equal to one millimeter. This proves sufficient for the flow around the friction pad.

[0018] Another preferred embodiment of the groove structure is characterized in that each friction pad has an X-shaped embossed portion, wherein the intersection of the X-shaped embossed portions is centrally located about the respective friction pad. The X-shaped embossed portions, also referred to as intersecting embossed portions, are self-symmetrical. Each X-shaped embossed portion includes four centrally intersecting grooves, which may also be called main grooves. Furthermore, depending on the size of the friction pad, the X-shaped embossed portions also include additional grooves laterally to the four main grooves; these additional grooves may also be called edge grooves or auxiliary grooves. The edge grooves or auxiliary grooves are also only partially formed depending on the size of the friction pad.

[0019] Another preferred embodiment of the groove structure is characterized in that the X-shaped embossing portion has groove angles between 90 degrees and 110 degrees in both the radially inner and radially outer directions, wherein the X-shaped embossing portion has groove angles between 80 degrees or 90 degrees and 100 degrees in opposite circumferential directions. The radially inner and radially outer directions can also be referred to as lower and upper in terms of groove angles. Similarly, the opposite circumferential directions can also be referred to as right and left in terms of groove angles. Particularly preferably, the groove angles in the opposite circumferential directions, i.e., the left and right groove angles, have degrees between 85 degrees and 95 degrees.

[0020] Another preferred embodiment of the groove structure is characterized in that the friction pad has a width and a height having a width-to-height ratio less than 2.5 for each friction pad. The width-to-height ratio of the friction pad is preferably between 3.1 and 2.4. This width-to-height ratio is advantageously applicable in two rotational directions in which the friction pad can be twisted relative to the steel sheet.

[0021] Another preferred embodiment of the groove structure is characterized in that the friction pad is aligned at the groove of the inner tooth portion of the carrier sheet. Therefore, direct oiling of the friction pad, especially the X-shaped embossed portion of the friction pad, can be achieved in a simple manner and method.

[0022] Another preferred embodiment of the groove structure is characterized in that the dividing angle of the friction pad is between 140 degrees and 160 degrees. The dividing angle describes the degree of inclination of the dividing groove relative to the radial direction extending through the central intersection of the X-shaped embossed portion of the corresponding friction pad.

[0023] Another preferred embodiment of the groove structure is characterized in that all friction pads have the same shape and size. This also proves advantageous in the manufacture and installation of the friction pads. The term "same shape and size" includes manufacturing tolerances.

[0024] The present invention also relates to a friction pad for the previously described groove structure. The friction pad may be traded separately. Attached Figure Description

[0025] Further advantages and advantageous designs of the present invention are the subject of the following figures and descriptions.

[0026] Detailed explanation: Figure 1 Relationship shown: intake and drag torque Figure 2 Show the purpose and improvement Figure 3 The groove design according to the present invention is shown. Figure 4 The dimensions of the groove design according to the present invention are shown. Figure 5 The dimensions of the groove design according to the present invention are shown. Figure 6 The dimensions of the groove design according to the present invention are shown. Figure 7 The oil flow path is shown in the tank design according to the present invention. Figure 8 The dimensions of the groove design according to the present invention are shown. Figure 9 The dimensions of the groove design according to the present invention are shown. Detailed Implementation

[0027] Pad segmentation: at least 8 pads arranged in a ring, each having a segmentation groove between them ( Figure 6 (6), Figure 9 ) Pad angle ( Figure 4 (1) Between 60 degrees and 120 degrees (see details) Figure 8 and Figure 9 ) The outer edge of the pad is rounded along the circumference, preferably >= 1mm. Figure 5 (2) Symmetrical cross-embossed areas (X embossed areas) on the trapezoidal pad Figure 7 ).

[0028] The intersection of the X-shaped embossed section at the center of the pad.

[0029] The ratio of the width (3) to the height (4) of the pad is less than 2.5 (preferably 2.1 to 2.4). Figure 5 ) The width of the embossing section, i.e., the embossing groove (5) > the width of the pad spacing, i.e., the dividing groove (6) Figure 6 ) X-groove angle ( Figure 6 ): Up / Down (7): Between 90 and 110 degrees, Right / Left (8): Between 90 degrees and 100 degrees (preferably 85 degrees and 95 degrees) Orientation of the teeth relative to the pad: direct oiling of the pad ( Figure 7 (9) Figure 9 ) The angle of the segment between 140 degrees and 160 degrees ( Figure 9 > Angle of the imprinting section (7), (8) (X groove angle, Figure 6 ) The ratio of the area of ​​the dividing part (the area of ​​the dividing groove (6)) to the area of ​​the imprinting part (the area of ​​the imprinting groove (5)) Figure 6 The ratio is at least 1:2, preferably between 1:2 and 1:4. Unlike Figures 11 and 12 in WO 2016 180 540 A1, the groove design according to the present invention does not contain an annular groove, thereby yielding the following advantages: Improve the frictional power input and utilization of thermal mass, which is lacking due to existing annular grooves.

[0030] Improve the wear performance of friction materials.

[0031] The rotationally symmetrical trapezoidal shape of the waffle results in uniform cooling and lubrication.

[0032] Improved friction coefficient creation through more efficient oil discharge.

[0033] Unlike in US 2007 0000 747 A1, the groove design according to the present invention has the same groove width as the dividing grooves between the pads in order to compensate for the oil delivery effect or accumulation effect in the internally oiled friction system.

[0034] The groove design according to the invention also does not contain purely radial grooves in order to reduce the lubricating oil wedge effect at the groove edges and reduce hydrodroplaning when switching (opening / closing) the friction system.

[0035] The groove design according to the present invention can be referred to as a trapezoidal waffle design, comprising a trapezoidal pad having an X-groove waffle imprinting portion: The embossing section causes a decrease in the fiber density at the stamped pad (resulting in a decrease in drag torque). The ratio of the dividing section (dividing groove) to the imprinting section (imprinting groove): the ratio is at least 1:2, preferably between 1:2 and 1:4. This allows for the finding of the optimal balance between cooling and degreasing in the friction system (see...). Figure 7 Through coordinated imprinting, the cooling oil can be optimally guided to the surfaces of the mating friction discs (see...). Figure 7 This improves convective heat transfer (cooling). Simultaneously, in the disconnected state, the plates can be separated (with the aid of lubricating oil), and intake can be improved (lower drag torque).

[0036] exist Figure 1 The diagram illustrates how air intake 26 is achieved through the delivered volumetric flow 24 if the intake exceeds the supplied volumetric flow 25. From this limit, the gap filling 26 decreases, and air is contained in the lubrication gaps between the plates. From this limit, the supplied volumetric flow 25 contains air. (The following...) Figure 2 As can be seen, intake 26 occurs under the condition of maximum drag torque 27.

[0037] exist Figure 2 The diagram illustrates how the load-bearing friction component 15 is used to move the intake air 28 towards lower speeds in the drag torque variation curve 30. Through... Figure 3 The groove structure shown can improve the delivery of cooling and / or lubricating media.

[0038] exist Figures 3 to 9 The diagram shows a groove structure 10 according to the present invention, also referred to as a groove design. The groove structure 10 includes friction pads 11 and 12 disposed on a support plate 18. The support plate 18, together with the friction pads 11 and 12, is referred to as a friction plate 19.

[0039] Friction pads 11 and 12 both have a trapezoidal shape with rounded corners. In the circumferential direction, friction pads 11 and 12 are spaced apart from each other, so that dividing grooves 9, 13, and 14 are respectively formed between two adjacent friction pads 11 and 12. The depth of dividing grooves 9, 13, and 14 is limited by the bearing plate 18.

[0040] exist Figure 3 As can be seen, the short base of the trapezoidal friction pad 11 is positioned radially inward. The short base of the trapezoidal friction pad 12 is positioned radially outward. Therefore, it can be concluded that... Figure 3 As can be seen, the dividing grooves 9 and 13 are inclined radially and set in opposite directions.

[0041] In addition, Figure 3 As can be seen, the bearing plate 18 has an internal toothed portion 17, which has teeth 15 and grooves 16 between the teeth 15. Friction pads 11 and 12 are respectively associated with the grooves 16.

[0042] Friction pads 11 and 12 are also equipped with an X-shaped embossing section 40. Figure 3 As can be seen, the friction pad 12 is aligned with the groove 16 of the inner toothed portion 17 of the carrier piece 18 by its X-shaped imprint 40.

[0043] exist Figure 4 As can be seen, the friction pad 12 with the X-shaped embossing portion 40 comprises a total of eight embossing grooves 41 to 48. The embossing grooves 41 to 44 are arranged in a cross shape and form an X with a center 49, the center being indicated by a circle at the center of the friction pad 12. The friction pad 12 is symmetrical about a centrally located axis of symmetry 50.

[0044] Imprint grooves 41 to 44 are also called main grooves or central grooves. Imprint grooves 45 to 48 are also called edge grooves or auxiliary grooves. Due to the trapezoidal shape of the friction pad 12, edge grooves 45 and 46 are not always fully formed.

[0045] Each corner of the friction pad 12 is associated with an inner angle 1. Preferably, at least eight trapezoidal friction pads 11, 12 are clamped onto the support plate 18. The inner angle 1 has a degree between sixty and one hundred and twenty degrees.

[0046] exist Figure 5 In the diagram, the width of the friction pad 12 is indicated by the double arrow 3. The height of the friction pad 12 is... Figure 5 The double arrow 4 indicates this. All corners of the friction pad 12 are rounded with a radius of 2.

[0047] exist Figure 6In the text, the width of the embossing groove 41 in the friction pad 12 is indicated by double arrow 5. The width of the dividing groove 13 is indicated by double arrow 6. All dividing grooves 9 and 13 preferably have substantially the same groove width 6. Embossing grooves 41 to 48 also preferably have substantially the same groove width 5.

[0048] The groove angle between impression grooves 43 and 44 is indicated by double arrow 7. Groove angle 7 is also called radially inner or lower groove angle 7. Similarly, the groove angle 7 between impression grooves 41 and 42 is also called radially outer or upper groove angle 7.

[0049] Between the printing grooves 41 and 43 Figure 6 The left groove angle is indicated by the double arrow 8. A similar groove angle between the imprint grooves 42 and 44 is called the right groove angle. The left groove angle 8 and the right groove angle 7 are also called opposite groove angles in the circumferential direction.

[0050] exist Figure 7 In the figure, the four corner portions of the friction pad 12 are associated with reference numerals 31 to 34. All corner portions 31 to 34 of the friction pad 12 are rounded. The friction pad 12 is aligned with its longer bottom edge relative to the groove 16 of the inner tooth portion 17 of the carrier plate 18.

[0051] Arrow 59 indicates the incoming cooling medium, particularly oil. Oil 59 is supplied, for example, via the external teeth of a plate carrier (not shown). Figure 7 Arrows 51 to 54 indicate how the radially internally supplied oil 59 is distributed in the X-imprint portion 40 of the friction pad 12. The oil 59 is then discharged radially externally at the friction plate 19.

[0052] exist Figure 8 The inner angles of friction pads 11 and 12 are indicated by double arrows 61 to 64 and 71 to 74. The inner angles 61 to 64 have degrees of 61.5, 119.8, 119.8, and 61.5. The inner angles 71 to 74 of friction pad 12 have degrees of 115.3, 163.4, 163.4, and 115.3.

[0053] exist Figure 9 In the diagram, double arrows 77 and 78 indicate the dividing angle. Dividing angle 77 is 147.5 degrees and is formed between dashed lines 76 and 79. Dashed line 76 corresponds to the radially extending axis of symmetry of the friction pad 11. Dashed line 79 runs along the radial direction of the friction pad 11. Figure 9 The left waist extends from the middle.

[0054] The dividing angle 78 is 157.5 degrees and is formed between dashed line 50 and dashed line 80. Dashed line 50 corresponds to the radially extending axis of symmetry of the friction pad 12. Dashed line 80 is located on the friction pad 12... Figure 9It extends from the right waist.

[0055] List of reference numerals 1. Pad the interior corner 2. Rounding radius 3 Width 4. Height 5 slot width 6 slot width 7. Groove Angle 8 slot angle 9. Dividing slots 10-slot structure 11 Friction Pads 12 Friction Pads 13 Dividing slots 14 Dividing slots 15 teeth 16 tooth grooves 17. Internal teeth 18 bearing plates 19 Friction Plates 20 x-axis 21 y-axis 22 y-axis 23 y-axis 24. Conveyed volumetric flow 25. Supply volumetric flow 26. Air Intake 27. Driving torque 28 Intake 30. Driving torque variation curve 31 Corner pad 32 Corner pad 33 Corner pad 34 Corner pad 40 X Imprint Section 41 Imprinting groove 42 Imprinting groove 43 Imprinting groove 44 Imprinting groove 45 Imprinting groove 46 Imprinting groove 47 Imprinting groove 48 Imprinting groove 49 Center 50 Axis of symmetry 51 arrows 52 arrows 53 arrows 54 arrows 57 arrows 58 arrows 59 arrows 61. Pad interior angle 62. Inner angle pad 63. Pad interior angle 64. Pad interior angle 71. Pad interior angle 72. Inner angle pad 73. Pad interior angle 74. Pad interior angle 76. Axis of symmetry 77 Dividing Angle 78 Dividing Angle Line 79 80 lines

Claims

1. A groove structure (10) for a friction pad (19), wherein the groove structure (10) is formed by means of friction pads (11, 12), and the friction pads (11, 12) have a trapezoidal shape, characterized in that, Each friction pad (11, 12) has an embossing groove (41 to 48) comprising a central groove (41 to 44) arranged in a cross shape and presenting an X-shaped embossed portion (40) with an intersection point (49) located at the center of the friction pad. The groove structure (10) comprises at least eight friction pads (11, 12) arranged in a ring, wherein a dividing groove (9, 13, 14) is provided between two adjacent friction pads (11, 12) in the circumferential direction, and the embossing groove (41 to 48) in the friction pad (11, 12) has a larger groove width (5) than the dividing groove (9, 13, 14).

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

4.

3. The groove structure according to claim 1, characterized in that, The X-embossing portion (40) has a groove angle (7) between 90 degrees and 110 degrees in the radial interior and radial exterior, wherein the X-embossing portion (40) has a groove angle (8) between 80 degrees or 90 degrees and 100 degrees in opposite circumferential directions.

4. The groove structure according to claim 1, characterized in that, The friction pads (11, 12) have a width (3) and a height (4), the width and the height having a ratio of width (3) to height (4), the ratio being less than 2.5 for each friction pad (11, 12).

5. The groove structure according to claim 1, characterized in that, The friction pads (11, 12) are aligned at the tooth groove (16) of the inner tooth portion (17) of the bearing plate (18).

6. The groove structure according to any one of the preceding claims, characterized in that, The dividing angles (77, 78) of the friction pads (11, 12) are between 140 degrees and 160 degrees.

7. A friction pad (11, 12) for a groove structure (10) according to any one of the preceding claims.

Images