(19)
(11)EP 2 791 526 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
11.12.2019 Bulletin 2019/50

(21)Application number: 12856820.1

(22)Date of filing:  17.12.2012
(51)International Patent Classification (IPC): 
F16D 13/52(2006.01)
F16D 69/00(2006.01)
F16D 13/60(2006.01)
(86)International application number:
PCT/US2012/070130
(87)International publication number:
WO 2013/090905 (20.06.2013 Gazette  2013/25)

(54)

SEGMENTED FRICTION MATERIAL FOR CLUTCHES

SEGMENTIERTES REIBUNGSMATERIAL FÜR KUPPLUNGEN

MATÉRIAU DE FRICTION SEGMENTÉ POUR EMBRAYAGES


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 16.12.2011 US 201113328159

(43)Date of publication of application:
22.10.2014 Bulletin 2014/43

(73)Proprietor: Eaton Corporation
Cleveland, OH 44122 (US)

(72)Inventors:
  • CHAVDAR, Bulent
    St. Clair Shores, MI 48081 (US)
  • ROTH, Scott, T.
    Auburn Hills, MI 48326 (US)

(74)Representative: Schwan Schorer & Partner mbB 
Patentanwälte Bauerstrasse 22
80796 München
80796 München (DE)


(56)References cited: : 
EP-A2- 2 028 382
KR-A- 20110 011 072
US-A1- 2004 074 733
US-A1- 2008 179 161
US-B2- 6 712 190
DE-A1-102010 021 900
US-A1- 2003 051 967
US-A1- 2007 193 847
US-A1- 2008 302 625
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    CROSS-REFERENCE TO RELATED APPLICATION



    [0001] This application claims priority to U.S. Patent Application No. 13/328,159, filed December 16, 2011.

    TECHNICAL FIELD



    [0002] The present teachings relate to friction material for clutches, and more particularly to a friction material having a configuration suitable for wet clutch applications.

    BACKGROUND



    [0003] The present teachings generally relate to a friction material that can be used in clutch applications, such as a multi-plate wet clutch pack in a limited slip differential system. Friction plates and the friction material on the plates affect the reliability and quality of clutch engagement.

    [0004] Friction clutch plates are disclosed in US2003/0051967A1, DE102010021900A1, EP2028382A2, US2004/0074733A1.

    [0005] When wet clutches engage and slide against each other, the contacting friction surfaces generate heat. Oil can be applied to the friction plates to cool the contacting components, either by center-fed forced cooling (where oil is pumped through channels in the center of an input shaft and exits through holes in the center of a clutch hub to flow into the clutch pack) or splash cooling (where a differential housing is filled with oil that splashes on the clutch plates). Forced cooling systems allow adjustment of the oil flow rate based on the cooling demand, but incorporating the pump and fluid channels adds complexity to the differential system.

    [0006] By contrast, splash cooling is a passive cooling method and does not require any special modifications to the differential system. However, the clutch packs in LSD systems are always engaged (e.g., adjacent friction plates and separator plates are always in contact with each other). This makes it difficult for sufficient oil to reach the clutch interface and cool the clutch. In other words, splash-cooled wet clutches tend to have low cooling efficiency.

    SUMMARY



    [0007] One aspect of the present teachings is directed to a friction plate for a clutch assembly. The friction plate comprises a core plate having an inner diameter and a first outer diameter and a plurality of friction segments made of a friction material. A plurality of grooves are disposed between said plurality of friction segments, wherein each segment has tapered sides so that the grooves have a first width adjacent the first outer diameter and a second width, which is smaller than the first width, adjacent the inner diameter.

    [0008] Another aspect of the present teachings is directed to a clutch assembly having a plurality of the friction plates described above disposed in an alternating fashion with a plurality of separator plates.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0009] 

    Figure 1 is an exploded view of a wet clutch pack according to one aspect of the teachings;

    Figure 2A is a plan view of a friction plate that can be used in the system of Figure 1;

    Figure 2B is a close-up view of the friction plate in Figure 2A;

    Figure 2C is a close-up perspective view of the friction plate in Figure 2A;

    Figure 3 is a plan view of friction material that can be used in the friction plate of Figure 2;

    Figure 4 is a plan view of another arrangement of friction material that can be used in the friction plate of Figure 2.


    DETAILED DESCRIPTION



    [0010] Figure 1 illustrates components in a wet clutch 10 according to one aspect of the teachings. The wet clutch 10 can include friction plates 12 and separator plates 14 arranged in an alternating manner.

    [0011] As shown in Figures 2A, 2B, and 2C, the friction plate 12 can include a core plate 16 and a friction lining 18 bonded to the core plate 16 via any known process. The separator plate 14 and the core plate 16 may both be made of steel. The core plate 16 may have ears 17 to act as clutch guides.

    [0012] The friction lining 18 can be formed as a plurality of segments 20 with side surfaces 21 forming grooves 22 in between the segments 20. The friction lining 18 may be formed of any appropriate material, such as a paper-based friction material containing aramid or other high-strength fibers and fillers and saturated with a thermosetting resin, such as a phenolic resin. Options for the friction material structure include woven, pultruded or compression-molded structures. Options for the friction material itself may include polyamide, carbon, ceramic, or any combination thereof. These options are only examples: the specific material and material structure is not critical to the teachings, and those of ordinary skill in the art will recognize that other options are within the scope of the teachings.

    [0013] Grooves 22 act as fluid paths to allow oil to flow between the friction plates 12 and separator plates 14 for cooling. Deeper grooves 22 improve cooling efficiency and reduces thermal degradation of the friction lining 18 because deeper grooves 22 allow more cooling oil to circulate between the plates 12, 14. The grooves 22 can be made in various ways, such as molding grooves into the friction lining 18 or cutting the friction lining 18 to form the grooves 22. Cutting or machining allows formation of deeper grooves 22 (i.e., thicker side surfaces 21) than molding and therefore can potentially improve the cooling efficiency of the wet clutch 10. However, cutting the friction lining 18 material can create fuzziness and loose fibers at the cut edges due to fibers in the friction lining 18 material. The fuzzy edges can restrict oil flow, and the loose fibers can contaminate the oil.

    [0014] The friction lining 18 shown in Figures 1 through 3 solves the above problems by dividing the friction lining 18 into discrete segments 20. Creating separate segments 20 maximizes the depth of the grooves 22 and provides smooth side surfaces 21 that do not impede oil flow.

    [0015] The number and shape of the segments 20 as well as the direction (e.g., radial vs. angled), width, and shape of the grooves 22 all affect the cooling efficiency of the wet clutch 10 and control the amount of thermal degradation in the friction lining 18. For example, if the segments 20 are too large, there will be fewer grooves 22, thereby reducing the amount of oil circulating through the wet clutch 10, diminishing cooling efficiency, and increasing thermal degradation of the friction lining 18. However, if there are too many segments 20 and grooves 22, the increased number of grooves 22 reduces the load capacity of the wet clutch 10 by reducing the land area of the friction lining 18, thereby increasing the amount of friction load each segment 20 must bear. This can potentially increase the wear rate of the friction lining 18 and reduce its compression fatigue life and reliability.

    [0016] The number of friction segments 20 forming the friction lining 18 can be optimized to provide the best compromise between cooling efficiency and load capacity. Figures 2 and 3 illustrate two possible aspects of the teachings for purposes of illustration and not limitation. Figure 3 illustrates a friction lining 18 arrangement having twelve friction segments 20 and twelve grooves 22, while Figure 4 illustrates a friction lining 18 arrangement having sixteen friction segments 20 and sixteen grooves 22.

    [0017] In both of these aspects, adjacent side surfaces 21 of the grooves 22 may taper slightly inward from an outer diameter of the core plate 16 to an inner diameter of the core plate 16. The side surfaces 21 of the segments 20 can be straight, flared outward, or tapered slightly inward so that the sides surfaces of adjacent segments 20 form the inwardly tapering grooves 22. Outer edges of the friction segments 20 form an outer diameter of the friction lining 18, while inner edges of the friction segments 20 form an inner diameter of the friction lining 18. In one aspect, the width of the tapered grooves 22 may be about 5 mm at the friction lining's 18 outer diameter and about 3 mm at the friction lining's 18 inner diameter to allow oil to flow into the wet clutch 10 easily.

    [0018] Also, each friction segment 20 may have rounded corners 38 at the outer edges. In one aspect of the teachings, the radii of the rounded corners are generous, on the order of mm. The rounded corners 38, together with the tapered side surfaces 21 forming the grooves 22, create a funnel shape 23, directing oil from the outer diameter of the core plate 16 toward the inner diameter 30 of the core plate 16 via random splashing and gravitational forces. In other words, the funnel shape formed by the friction segments 20 funnels oil into the clutch interface

    [0019] (i.e., between the friction plates 12 and the separator plates 14). As centrifugal forces push oil out of the wet clutch 10 during differential rotation, particularly during high-speed rotation without slippage, the rounded corners 38 guide the oil back into the clutch interface to maintain cooling action during low speed rotation with high slip speed.

    [0020] As shown in Figure 2B he friction lining 18 may also be shaped so the outer edges 33 of the friction segments 20 collectively form an outer diameter that is slightly less than the outer diameter of the core plate 16, creating a margin 44 of bare metal around the perimeter of the friction lining 18. In one aspect of the teachings, the margin 44 is approximately 1-2 mm wide. This margin 44 can improve cooling efficiency, as will be described in greater detail below.

    [0021] In one aspect of the teachings, the number, shape, size, and arrangement of the friction segments 20 are selected to provide a reaction torque sufficient to provide traction if a driven wheel encounters a slip condition. In such slip conditions, the wet clutch 10 can experience high sliding speeds (e.g., greater than 500 rpm), high pressures (e.g., greater than 3 MPa), and long slip durations (e.g., greater than 5 seconds). Therefore, the friction segments 20 can be designed so the overall friction lining 18 can withstand high density power inputs (e.g., greater than 2 W/mm2).

    [0022] During clutch operation, heat generated by the friction lining 18 is absorbed by the core plate 16 and the separator plate 14. Thus, the interface between the friction plates 12 and the separator plates 14 can reach temperatures on the order of 400 C, which is hot enough to potentially degrade the friction lining 18. To optimize cooling, contact between the oil and both the core plate 16 and separator plate 14 should be maximized so the oil can quickly absorb retained heat in the plates 14, 16. Since splashed oil initially tends to sit on the outside of the wet clutch 10, the margin 44 increases the amount of metal contacting the oil before it is eased into the grooves 22, thereby improving cooling efficiency. Also, the margin 44 helps create surface tension that holds in the oil between the core plates 16 and the separator plates 14, prolonging the contract between the metal of the plates 14, 16 and thereby increasing the heat transfer between the hot metal of the plates 14, 16 and the oil.

    [0023] It will be appreciated that the above teachings are merely exemplary in nature and is not intended to limit the present teachings, their application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present teachings as defined in the claims. Furthermore, the mixing and matching of features, elements and/or functions between various examples is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise, above. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present teachings not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims.


    Claims

    1. A friction plate (12) for a clutch assembly, the friction plate comprising:

    a core plate (16) having an inner diameter and a first outer diameter; and

    a plurality of friction segments (20) made of a friction material; and

    a plurality of grooves (22) disposed between said plurality of friction segments, wherein the grooves have a first width adjacent the first outer diameter and a second width, which is smaller than the first width, adjacent the inner diameter;

    characterized in that the sides surfaces (21) of each friction segment (20) taper inwardly from a margin (44) of the first outer diameter to the inner diameter.
     
    2. The friction plate (12) of claim 1, wherein each of said plurality of grooves (22) has a funnel shape.
     
    3. The friction plate (12) of claim 1, wherein each friction segment (20) has an outer edge adjacent the outer diameter, and wherein at least one friction segment has at least one, preferably two rounded corners (38) on the outer edge.
     
    4. The friction plate (12) of claim 1, wherein each of said plurality of grooves (22) is formed by the side surfaces (21) of adjacent friction segments (20) such that each of said plurality of grooves is tapered.
     
    5. The friction plate (12) of claim 1, wherein each friction segment (20) has an outer edge such that the combined outer edges form a second outer diameter, and wherein the second outer diameter is smaller than the first outer diameter to form the margin (44) not covered by friction material on the core plate (16).
     
    6. The friction plate (12) of claim 1, wherein the friction material comprises at least one material selected from paper, high-strength fibers, thermosetting resin, polyamide, carbon, and ceramic.
     
    7. The friction plate (12) of claim 1, wherein the friction material is one selected from a woven material, a paper-based material, a pultruded material, and a compression-molded material.
     
    8. A clutch assembly, comprising
    a plurality of friction plates (12), each friction plate having

    a core plate (16) having an inner diameter and a first outer diameter; and

    a plurality of friction segments (20) made of a friction material; and

    a plurality of grooves (22) disposed between said plurality of friction segments, wherein the grooves have a first width adjacent the outer diameter and a second width smaller than the first width adjacent the inner diameter;

    wherein side surfaces (21) of each friction segment (20) taper inwardly from a margin (44) of the first outer diameter to the inner diameter;
    and
    a plurality of separator plates (14) alternately disposed between said plurality of friction plates.
     
    9. The clutch assembly of claim 8, wherein each of said plurality of grooves (22) has a funnel shape.
     
    10. The clutch assembly of claim 8, wherein at least one of the core plate (16) and the separator plate are made of steel.
     
    11. The clutch assembly of claim 8, wherein each friction segment (20) has an outer edge adjacent the outer diameter and at least one, preferably two rounded corners (38) on the outer edge.
     
    12. The clutch assembly of claim 8, wherein each of said plurality of grooves (22) is formed by the side surfaces (21) of adjacent friction segments (20) such that each of said plurality of grooves is tapered.
     
    13. The clutch assembly of claim 8, wherein each friction segment (20) has an outer edge such that the combined outer edges form a second outer diameter, and wherein the second outer diameter is smaller than the first outer diameter to form the margin (44) not covered by friction material on the core plate (16), and wherein preferably the margin of the core plate faces the separator plate (14) such that fluid can directly and simultaneously contact the margin of the core plate and the separator plate.
     
    14. The clutch assembly of claim 8, wherein the friction material comprises at least one material selected from the consisting of paper, high-strength fibers, thermosetting resin, polyamide, carbon, and ceramic.
     
    15. The clutch assembly of claim 8, wherein the friction material is one selected from a woven material, a paper-based material, a pultruded material, and a compression-molded material.
     


    Ansprüche

    1. Reibungsplatte (12) für eine Kupplungsanordnung, wobei die Reibungsplatte Folgendes umfasst:

    eine Kernplatte (16), einen Innendurchmesser und einen ersten Außendurchmesser aufweisend; und

    mehrere Reibungssegmente (20), gefertigt aus einem Reibungsmaterial; und

    mehrere Nuten (22), angeordnet zwischen den mehreren Reibungssegmenten, wobei die Nuten eine erste Breite angrenzend an den ersten Außendurchmesser und eine zweite Breite, die kleiner als die erste Breite ist, angrenzend an den Innendurchmesser, aufweisen; dadurch gekennzeichnet, dass die Seitenflächen (21) der einzelnen Reibungssegmente (20) von einem Rand (44) des ersten Außendurchmessers nach innen zum Innendurchmesser aufeinander zulaufen.


     
    2. Reibungsplatte (12) nach Anspruch 1, wobei jede der mehreren Nuten (22) eine Trichterform hat.
     
    3. Reibungsplatte (12) nach Anspruch 1, wobei jedes Reibungssegment (20) eine äußere Kante angrenzend an den Außendurchmesser hat, und wobei zumindest ein Reibungssegment mindestens eine, vorzugsweise zwei abgerundete Ecken (38) an der äußeren Kante hat.
     
    4. Reibungsplatte (12) nach Anspruch 1, wobei jede der mehreren Nuten (22) durch die Seitenflächen (21) von aneinander angrenzenden Reibungssegmenten (20) gebildet wird, sodass jede der mehreren Nuten konisch ist.
     
    5. Reibungsplatte (12) nach Anspruch 1, wobei jedes Reibungssegment (20) eine äußere Kante hat, sodass die kombinierten äußeren Ränder einen zweiten Außendurchmesser bilden, und wobei der zweite Außendurchmesser kleiner als der erste Außendurchmesser ist, um den Rand (44) zu bilden, der nicht durch Reibungsmaterial auf der Kernplatte (16) bedeckt ist.
     
    6. Reibungsplatte (12) nach Anspruch 1, wobei das Reibungsmaterial zumindest ein Material umfasst, das ausgewählt wird aus Papier, hochfesten Fasern, warmhärtendem Kunststoff, Polyamid, Carbon und Keramik besteht.
     
    7. Reibungsplatte (12) nach Anspruch 1, wobei das Reibungsmaterial eines ist, das aus einem gewebten Material, einem papierbasierten Material, einem stranggezogenen Material und einem formgepressten Material ausgewählt wird.
     
    8. Kupplungsanordnung, die Folgendes umfasst:
    mehrere Reibungsplatten (12), wobei jede Reibungsplatte Folgendes aufweist:

    eine Kernplatte (16), einen Innendurchmesser und einen ersten Außendurchmesser aufweisend; und

    mehrere Reibungssegmente (20), gefertigt aus einem Reibungsmaterial; und

    mehrere Nuten (22), angeordnet zwischen den mehreren Reibungssegmenten, wobei die Nuten eine erste Breite angrenzend an den Außendurchmesser und eine zweite Breite, die kleiner als die erste Breite ist, angrenzend an den Innendurchmesser aufweisen;

    wobei Seitenflächen (21) der einzelnen Reibungssegmente (20) von einem Rand (44) des ersten Außendurchmessers nach innen zum Innendurchmesser aufeinander zulaufen;

    und

    mehrere Trennplatten (14), alternierend zwischen den mehreren Reibungsplatten angeordnet.


     
    9. Kupplungsanordnung nach Anspruch 8, wobei jede der mehreren Nuten (22) eine Trichterform hat.
     
    10. Kupplungsanordnung nach Anspruch 8, wobei zumindest eine aus der Kernplatte (16) und der Trennplatte aus Stahl gefertigt ist.
     
    11. Kupplungsanordnung nach Anspruch 8, wobei jedes Reibungssegment (20) eine äußere Kante angrenzend an den Außendurchmesser hat, und mindestens eine, vorzugsweise zwei abgerundete Ecken (38) an der äußeren Kante hat.
     
    12. Kupplungsanordnung nach Anspruch 8, wobei jede der mehreren Nuten (22) durch die Seitenflächen (21) von aneinander angrenzenden Reibungssegmenten (20) gebildet wird, sodass jede der mehreren Nuten konisch ist.
     
    13. Kupplungsanordnung nach Anspruch 8, wobei jedes Reibungssegment (20) eine äußere Kante hat, sodass die kombinierten äußeren Kanten einen zweiten Außendurchmesser bilden, und wobei der zweite Außendurchmesser kleiner als der erste Außendurchmesser ist, um den Rand (44) zu bilden, der auf der Kernplatte (16) nicht durch Reibungsmaterial bedeckt ist, und wobei vorzugsweise der Rand der Kernplatte zur Trennplatte (14) zeigt, sodass Fluid direkt und gleichzeitig in Kontakt mit dem Rand der Kernplatte und der Trennplatte kommen kann.
     
    14. Kupplungsanordnung nach Anspruch 8, wobei das Reibungsmaterial zumindest ein Material umfasst, das aus der ausgewählt wird, die aus Papier, hochfesten Fasern, warmhärtendem Kunststoff, Polyamid, Carbon und Keramik besteht.
     
    15. Kupplungsanordnung nach Anspruch 8, wobei das Reibungsmaterial eines ist, das aus einem gewebten Material, einem papierbasierten Material, einem stranggezogenen Material und einem formgepressten Material ausgewählt wird.
     


    Revendications

    1. Plaque de friction (12) pour un assemblage d'embrayage, la plaque de friction comprenant :

    une plaque de cœur (16) ayant un diamètre intérieur et un premier diamètre extérieur ; et

    une pluralité de segments de friction (20) faits en un matériau de friction ; et

    une pluralité de rainures (22) disposées entre ladite pluralité de segments de friction, lesquelles rainures ont une première largeur adjacente au premier diamètre extérieur et une deuxième largeur, qui est inférieure à la première largeur, adjacente au diamètre intérieur ;

    caractérisée en ce que des surfaces latérales (21) de chaque segment de friction (20) est effilé vers l'intérieur à partir d'une marge (44) du premier diamètre extérieur au diamètre intérieur.


     
    2. Plaque de friction (12) selon la revendication 1, dans laquelle chacune parmi ladite pluralité de rainures (22) a une forme d'entonnoir.
     
    3. Plaque de friction (12) selon la revendication 1, dans laquelle chaque segment de friction (20) a un bord extérieur adjacent au diamètre extérieur, et dans laquelle au moins un segment de friction a au moins un, de préférence deux coins arrondis (38) sur le bord extérieur.
     
    4. Plaque de friction (12) selon la revendication 1, dans laquelle chacune parmi ladite pluralité de rainures (22) est formée par les surfaces latérales (21) de segments de friction adjacents (20) de façon que chacune parmi ladite pluralité de rainures soit effilée.
     
    5. Plaque de friction (12) selon la revendication 1, dans laquelle chaque segment de friction (20) a un bord extérieur de façon que les bords extérieurs combinés forment un deuxième diamètre extérieur, et dans laquelle le deuxième diamètre extérieur est inférieur au premier diamètre extérieur pour former la marge (44) non couverte par le matériau de friction sur la plaque de cœur (16).
     
    6. Plaque de friction (12) selon la revendication 1, dans laquelle le matériau de friction comprend au moins un matériau choisi parmi le papier, les fibres haute résistance, une résine thermodurcissable, un polyamide, le carbone, et une céramique.
     
    7. Plaque de friction (12) selon la revendication 1, dans laquelle le matériau de friction est l'un choisi parmi un matériau tissé, un matériau à base de papier, un matériau pultrudé, et un matériau moulé par compression.
     
    8. Assemblage d'embrayage comprenant
    une pluralité de plaques de friction (12), chaque plaque de friction ayant
    une plaque de cœur (16) ayant un diamètre intérieur et un premier diamètre extérieur ; et
    une pluralité de segments de friction (20) faits en un matériau de friction ; et
    une pluralité de rainures (22) disposées entre ladite pluralité de segments de friction, lesquelles rainures ont une première largeur adjacente au premier diamètre extérieur et une deuxième largeur, qui est inférieure à la première largeur, adjacente au diamètre intérieur ;
    et
    une pluralité de plaques de séparation (14) disposées en alternance entre ladite pluralité de plaques de friction.
     
    9. Assemblage d'embrayage selon la revendication 8, dans lequel chacune parmi ladite pluralité de rainures (22) a une forme d'entonnoir.
     
    10. Assemblage d'embrayage selon la revendication 8, dans lequel au moins l'une parmi la plaque de cœur (16) et la plaque de séparateur est faite en acier.
     
    11. Assemblage d'embrayage selon la revendication 8, dans lequel chaque segment de friction (20) a un bord extérieur adjacent au diamètre extérieur, et au moins un, de préférence deux coins arrondis (38) sur le bord extérieur.
     
    12. Assemblage d'embrayage selon la revendication 8, dans lequel chacune parmi ladite pluralité de rainures (22) est formée par les surfaces latérales (21) de segments de friction adjacents (20) de façon que chacune parmi ladite pluralité de rainures soit effilée.
     
    13. Assemblage d'embrayage selon la revendication 8, dans lequel chaque segment de friction (20) a un bord extérieur de façon que les bords extérieurs combinés forment un deuxième diamètre extérieur, et dans lequel le deuxième diamètre extérieur est inférieur au premier diamètre extérieur pour former la marge (44) non couverte par le matériau de friction sur la plaque de cœur (16), et dans lequel de préférence la marge de la plaque de cœur fait face à la plaque de séparateur (14) de façon qu'un fluide puisse directement et simultanément venir au contact de la marge de la plaque de cœur et de la plaque de séparateur.
     
    14. Assemblage d'embrayage selon la revendication 8, dans lequel le matériau de friction comprend au moins un matériau choisi parmi le papier, les fibres haute résistance, une résine thermodurcissable, un polyamide, le carbone, et une céramique.
     
    15. Assemblage d'embrayage selon la revendication 8, dans lequel le matériau de friction est l'un choisi parmi un matériau tissé, un matériau à base de papier, un matériau pultrudé, et un matériau moulé par compression.
     




    Drawing














    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description