DE102021131361A1 - Groove pattern for friction discs - Google Patents

Abstract

The invention relates to a groove pattern for friction discs, the groove pattern (10) being formed by means of friction lining pads and the friction lining pads having a pentagonal shape with five pad corners. The invention is characterized in that the pad corners (31-35) are rounded.

Description

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

• Nasslaufende Lamellenkupplungen und -bremsen finden breite Anwendung in konventionellen lastschaltbaren Getrieben, in neuartigen Hybridmodulen in hochbeanspruchten Antriebssträngen oder in schaltbaren E-Achsen, und stellen dabei leistungsfähige, hoch beanspruchte Bauteile dar. Die Forderungen nach geringerem CO2-Ausstoß und Verbesserung des Wirkungsgrades von Antriebssträngen in Kraftfahrzeuganwendungen sind von großer Bedeutung. Neben der Reduzierung von lastunabhängigen Verlusten bei Schaltelementen sind die thermische Belastung und die ausreichende Kühlung zu beachten. Im Spannungsfeld von Reibcharakteristik, Wärmehaushalt und Effizienz nimmt das Nutmuster - im Rahmen dieser Schrift auch als Padgeometrie bezeichnet - der Reiblamelle eine zentrale Rolle ein. (vgl. 1).

The scope of the invention:

• Wet-running multi-plate clutches and brakes are widely used in conventional power shift transmissions, in new hybrid modules in highly stressed drive trains or in switchable e-axles, and represent high-performance, highly stressed components. The demands for lower CO2 emissions and improved efficiency of drive trains in Automotive 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. In the area of tension between friction characteristics, heat balance and efficiency, the groove pattern - also referred to as pad geometry in the context of this document - of the friction lamella plays a central role. (see. 1 ).

EP 20 66 911 B1 discloses friction plates with a Y-shaped groove pattern distributed over the circumference in the radial direction.

WO 2018 171 834 A1 and WO 2018 171 835 A1 disclose a pad geometry of pentagonal friction lining pads.

The object of the invention is to minimize the drag losses in the case of friction discs by means of a suitable groove pattern. (see. 2 ).

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

The groove pattern according to the invention for friction disks therefore provides that the groove pattern is formed by means of friction lining pads and the friction lining pads have a pentagonal shape, with the corners being rounded off.

In this way, the drag torque is further reduced.

The pentagonal shape of the friction lining pads is basically composed of a rectangle and an isosceles triangle with a base that coincides with one side of the rectangle.

A preferred embodiment of the groove pattern is characterized in that all five pad interior angles have a degree of between 85 and 135 degrees. Included in each pad corner is a pad interior angle.

A further preferred exemplary embodiment of the groove pattern is characterized in that all 5 pad corners are rounded along the 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 rounding radii in the pad corners are greater than or equal to one millimeter. This has proven advantageous with regard to the flow around the friction lining pads.

A further preferred exemplary embodiment of the groove pattern is characterized in that identical or almost identical friction lining pads are arranged in a two-row pad design. Preferably, all of the friction lining pads are of substantially the same shape and size. Friction lining pads arranged in a radially inner row are advantageously directed radially outwards with their tips. Friction lining pads arranged in a radially outer row are advantageously directed radially inwards with their tips. The friction lining pads arranged in two rows are offset from one another in the circumferential direction in such a way that there are essentially y-shaped grooves between the friction lining pads. In a particularly advantageous manner, each tip of a friction lining pad is assigned a branching point which is spaced apart in the radial direction from an inner or outer peripheral edge of the groove pattern.

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 two for each friction lining pad. The width to height ratio of the friction lining pads is preferably between 1.5 and 1.7. This width-to-height ratio advantageously applies both to so-called inner pads arranged in an inner row and to so-called outer pads arranged in an outer row.

Another preferred embodiment of the groove pattern is characterized in that the groove pattern has inner webs with a width or a cross section that is smaller than twice the width or twice the cross section of branching intermediate grooves, which in turn is smaller, in particular narrower, i.e. less wide than the outer ridges of the groove pattern. The friction lining pads are preferably designed and arranged in the groove pattern in such a way that in the groove pattern results in a reduction in the flow cross-section of ten percent from the outside to the inside.

A further preferred exemplary embodiment of the groove pattern is characterized in that the groove angles of the intermediate grooves are between 90 and 100 degrees. A particularly preferred groove angle of the intermediate grooves is 90.2 degrees.

A further preferred exemplary embodiment of the groove pattern is characterized in that the outer webs have a radial extension that makes up 10 percent to 20 percent of the radial extension of the groove pattern. The outer webs particularly advantageously have a radial extent of 13.5 percent of the radial extent of the groove pattern.

The invention also 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.

• 1 Zusammenhänge: Lufteinzug und Schleppmoment
• 2 Aufgabe und Verbesserungen
• 3 erfindungsgemäßes Nutdesign
• 4 Dimensionierung des erfindungsgemäßen Nutdesigns
• 5 Dimensionierung des erfindungsgemäßen Nutdesigns
• 6 Dimensionierung des erfindungsgemäßen Nutdesigns
• 7 Ein inneres Pad des erfindungsgemäßen Nutdesigns
• 8 Ein äußeres Pad des erfindungsgemäßen Nutdesigns
  • • alle 5 Pad-Innenwinkel der Pad-Ecken zwischen 85 und 135 Grad (1) (Details siehe 7 und 8)
  • • alle 5 Pad-Ecken entlang der Umfangskontur verrundet (>= 1 mm) (2)
  • • zweireihiges Pad-Design mit nahezu identischen Pads: Innenpads und Außenpads als Fünfeck ausgeführt (Details siehe 7 und 8)
  • • Breiten (3) zu Höhen (4) Verhältnis jedes Pads unter 2 (vorzugsweise von 1,5 bis 1,7) (Innenpads und Außenpads analog)
  • • Breite bzw. Querschnitt Innensteg (5) < 2 * verzweigende Zwischennuten (6) < Außensteg (7) (Verkleinerung um 10% von außen nach innen)
  • • Nutwinkel (8) der Zwischennuten (6) zwischen 90 und 100 Grad, vorzugsweise 90,2 Grad
  • • Radiale Erstreckung Außensteg von 10% bis 20%, vorzugsweise 13,5% (9)
    • - Optimierung der Fertigungsqualität durch optimierte Padgeometrie.
    • - Verbesserung der Faserigkeit und der Kantenqualität und dadurch Reduzierung der Schleppmomente im geöffneten Zustand des Reibsystems.
    • - Robustes Verschleißverhalten der Padkanten und Padecken über die Lebenszeit. Erhaltung der Kantengeometrie (geringe Verrundung (1)) führt zu einem robusten, gleichbleibenden, hydrodynamischen Verhalten (Schmierkeil) und somit zu einer stabilen Reibcharakteristik. Applikationsaufwand der Regelung wird reduziert.
    • - schnellere Abfuhr des Ölfilmes durch eine weitere bevorzugte Ausführungsform der Erfindung, bei der der Verzweigungswinkel (8) zwischen 90° und 100°, vorzugsweise 90,2°, beträgt.
    • - Der Nutquerschnitt wird von innen nach außen größer (5)(6)(7) (Diffusorwirkung) und erzeugt eine zusätzliche Druckreduzierung in der Nut und verschiebt so den Lufteinzug zu niedrigen Drehzahlen. Das Schleppmoment kann somit weiter reduziert werden.
    • - Durch Zusammenführung der Zwischennuten (6) innerhalb der Reibfläche, kann durch die Reduzierung des Druckniveaus und Begünstigung des Lufteinzuges im Schmierspalt die effektiv wirksame Viskosität des Öl-Luft-Gemisches weiter reduziert werden und somit das Schleppmoment weiter verbessert werden.

They show in detail:

• 1 Relationships: air intake and drag torque
• 2 task and improvements
• 3 groove design according to the invention
• 4 Dimensioning of the groove design according to the invention
• 5 Dimensioning of the groove design according to the invention
• 6 Dimensioning of the groove design according to the invention
• 7 An inner pad of the groove design of the present invention
• 8th An outer pad of the groove design of the present invention
  • • all 5 pad inner angles of the pad corners between 85 and 135 degrees (1) (for details see 7 and 8th )
  • • all 5 pad corners rounded along the peripheral contour (>= 1 mm) (2)
  • • Two-row pad design with almost identical pads: inner pads and outer pads designed as a pentagon (for details see 7 and 8th )
  • • Width (3) to height (4) ratio of each pad under 2 (preferably from 1.5 to 1.7) (inner pads and outer pads analogously)
  • • Width or cross-section of inner web (5) < 2 * branching intermediate grooves (6) < outer web (7) (reduction by 10% from outside to inside)
  • • Groove angle (8) of the intermediate grooves (6) between 90 and 100 degrees, preferably 90.2 degrees
  • • Radial extension of the outer web from 10% to 20%, preferably 13.5% (9)
    • - Optimization of manufacturing quality through optimized pad geometry.
    • - Improvement of the fibrousness and the edge quality and thus reduction of the drag torques in the open state of the friction system.
    • - Robust wear behavior of the pad edges and pad corners over the lifetime. Preservation of the edge geometry (low rounding (1)) leads to a robust, constant, hydrodynamic behavior (lubrication wedge) and thus to stable friction characteristics. Application effort of the control is reduced.
    • - Faster removal of the oil film by a further preferred embodiment of the invention, in which the branching angle (8) is between 90° and 100°, preferably 90.2°.
    • - The cross-section of the groove increases from the inside to the outside (5)(6)(7) (diffuser effect) and creates an additional pressure reduction in the groove and thus shifts the intake of air to low speeds. The drag torque can thus be further reduced.
    • - By combining the intermediate grooves (6) within the friction surface, the effectively effective viscosity of the oil-air mixture can be further reduced by reducing the pressure level and promoting the intake of air in the lubricating gap, thus further improving the drag torque.

In 1 three Cartesian coordinate diagrams are shown one above the other. A speed during operation of the wet-running multi-plate clutch 1 with the friction part 15 is plotted in a suitable unit on an x-axis 20 . A volume flow is plotted in a suitable unit on a y-axis 21 . A gap filling degree is plotted in a suitable unit on a y-axis 22 . A drag torque is plotted in a suitable unit on a y-axis 23 .

In 1 is illustrated how an air intake 26 takes place through a conveyed volume flow 24 when this the supplied volume flow exceeds 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 2 below you can see that the air intake 26 occurs at a maximum drag torque 27 .

In 2 It is shown how a displacement of the air intake 28 to a low speed in a drag torque curve 30 is achieved with the claimed friction part 15 . through the in 3 shown groove pattern, the conveying effect of the cooling and / or lubricating medium can be improved.

In 3 a groove pattern 10 according to the invention is shown, which is also referred to as a groove design. The groove pattern 10 includes friction lining pads 11 to 17 which are arranged in two rows on a carrier plate 18 . The carrier disk 18 with the friction lining pads 11 to 17 is referred to as the friction disk 19 .

The friction lining pads 11 to 17 all have a pentagonal shape with rounded corners. The friction lining pads 15 to 17 are arranged in a radially inner row, while the friction lining pads 11 to 14 are arranged in a radially outer row of the groove pattern 10, which is designed in two rows. Tips of the friction lining pads 15 to 17 are directed radially outwards. Tips of the friction lining pads 11 to 14 are directed radially inwards.

In 9 a friction lining pad 40 with five corners 31 to 35 and five sides 41 to 45 is shown to illustrate the terminology. In the claimed groove pattern 10 all corners of the friction lining pads 11 to 17 are rounded. The corners 31 to 35 each enclose an interior angle. The size of the interior angles and also the size of the rounding radii in the corners 31 to 35 are described below with regard to the groove pattern 10 claimed.

In 4 the friction lining pad 12 is shown enlarged. Reference number 1 designates three pad interior angles. The size of the pad interior angles 1 can vary between 85 and 135 degrees.

In 5 all rounding radii in the corners of the friction lining pads 12 are denoted by 2 . A width of the friction lining pad 12 is denoted by 3 . A height of the friction lining pads 12 is denoted by 4 . A ratio of the widths 3 to the heights 4 of the friction lining pads 12 is preferably less than two. The width/height ratio of the friction lining pads is preferably between 1.5 and 1.7.

In 6 the width of an inner web between the friction lining pads 15 and 16 is indicated by a double arrow 5 . The width of an outer web between the friction lining pads 11 and 12 is indicated by a double arrow 7 .

The inner webs 5 of the groove pattern 10 are connected to the outer webs 7 by intermediate grooves 6 . A groove angle between two intermediate webs 6 is denoted by 8 . A radial extension of the outer web between the friction lining pads 11 and 12 is represented by a double arrow 9 .

The inner web is wider than the intermediate grooves 6. The width 5 of the inner web is smaller than twice the width of the intermediate grooves 6. The outer webs 7 have a width which is greater than twice the width of the intermediate grooves 6. From radially outward to radially inward, a reduction of ten percent is aimed for in groove pattern 10.

The groove angle 8 between the intermediate grooves 6 is preferably between 90 and 100 degrees, preferably 90.2 degrees. The radial extent 9 of the outer groove is preferably between 10 and 20 percent of the radial extent of the groove pattern 10, preferably 13.5 percent of the radial extent of the groove pattern 10.

This in 7 The friction lining pad 15 shown is also referred to as the inner pad because it is arranged in the inner row of the two-row groove pattern. Analogously this will be in 8th Friction lining pad 12 shown is also referred to as the outer pad. By double arrows 51 to 56 are in the 7 , 8th referred to as interior angles. The degrees of the interior angles 51 to 56 are 90.366 in the order mentioned; 93.2; 131.6; 96.8; 86.8; 134.8 degrees.

Reference List

1

Pad Inner Angle

2

curve radii

3

latitudes

4

heights

5

Broad

6

intermediate grooves

7

outer ridges

8th

groove angle

9

radial extension

10

groove pattern

11

friction pad

12

friction pad

13

friction pad

14

friction pad

15

friction pad

16

friction pad

17

friction pad

18

carrier lamella

19

friction disc

20

X axis

21

y-axis

22

y-axis

23

y-axis

24

conveyed volume flow

25

supplied flow rate

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

35

pad corner

40

friction lining pad

41

side

42

side

43

side

44

side

45

side

51

Pad Inner Angle

52

Pad Inner Angle

53

Pad Inner Angle

54

Pad Inner Angle

55

Pad Inner Angle

56

Pad Inner Angle

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 2066911 B1 [0003]
• WO 2018171834 A1 [0004]
• WO 2018171835 A1 [0004]

Claims (10)

Groove pattern (10) for friction discs (19), the groove pattern (10) being formed by means of friction lining pads (11-17) and the friction lining pads (11-17) having a pentagonal shape with five pad corners (31-35), characterized that the pad corners (31-35) are rounded. groove pattern claim 1 , characterized in that all five pad interior angles (1) have a degree between 85 and 135 degrees. Groove pattern according to one of the preceding claims, characterized in that all five pad corners (31-35) are rounded along the peripheral contour. Groove pattern according to one of the preceding claims, characterized in that the radii of curvature (2) in the pad corners (31-35) are greater than or equal to one millimeter. Groove pattern according to one of the preceding claims, characterized in that identical or almost identical friction lining pads (11-17) are arranged in a two-row pad design. Groove pattern according to one of the preceding claims, characterized in that the friction lining pads (11-17) have widths (3) and heights (4) which have a width (3) to height (4) ratio which is for each friction lining pad (11- 17) is less than two. Groove pattern according to one of the preceding claims, characterized in that the groove pattern (10) has inner webs with a width (5) or with a cross section which is smaller than twice the width (5) or twice the cross section of branching intermediate grooves (6) is, which in turn are smaller, in particular narrower, than the outer webs (7) of the groove pattern (10). Groove pattern according to one of the preceding claims, characterized in that the groove angles (8) of the intermediate grooves (6) are between 90 and 100 degrees. Groove pattern according to one of the preceding claims, characterized in that outer webs (7) have a radial extension (9) which makes up 10 percent to 20 percent of the radial extension of the groove pattern (10). Friction lining pad (11-17) for a groove pattern (10) according to any one of the preceding claims.

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