WO2001048391A1 - Method for producing a friction lining, in particular for motor vehicle - Google Patents

Method for producing a friction lining, in particular for motor vehicle Download PDF

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Publication number
WO2001048391A1
WO2001048391A1 PCT/FR2000/003556 FR0003556W WO0148391A1 WO 2001048391 A1 WO2001048391 A1 WO 2001048391A1 FR 0003556 W FR0003556 W FR 0003556W WO 0148391 A1 WO0148391 A1 WO 0148391A1
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WO
WIPO (PCT)
Prior art keywords
friction
temperature
lining
swelling
clutch
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Application number
PCT/FR2000/003556
Other languages
French (fr)
Inventor
Christian Biot
Original Assignee
Valeo
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Filing date
Publication date
Application filed by Valeo filed Critical Valeo
Priority to DE10084293.3T priority Critical patent/DE10084293B4/en
Priority to JP2001548874A priority patent/JP2003518596A/en
Publication of WO2001048391A1 publication Critical patent/WO2001048391A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
    • F16D69/02—Composition of linings ; Methods of manufacturing
    • F16D69/025—Compositions based on an organic binder
    • F16D69/026—Compositions based on an organic binder containing fibres
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D2200/00—Materials; Production methods therefor
    • F16D2200/0082—Production methods therefor
    • F16D2200/0086—Moulding materials together by application of heat and pressure

Definitions

  • Figures 1 to 3 each show the thermogram of a friction lining sample, defined below, which has been subjected to differential thermal analysis.
  • These raw materials can include, as is known, threads, binders, fillers.
  • the wires can consist of mineral fibers such as glass fibers, organic fibers, such as polyacrylonitrile fibers, metallic wires, such as copper, brass or other wires.
  • the binders, of the thermosetting type can be a combination of phenolic resins, melamine resins and rubbers.
  • the fillers can be vulcanizing agents for rubber, such as sulfur, fillers making it possible to adjust the friction such as zircon, silicates, kaolins, silico-aluminates, sulphides, for example pyrites or others, silicas, ceramic beads, carbon black, coke, graphites, oxides, such as magnesia, iron oxides, or the like, calcium carbonate, mica, strong bases, such as potash or soda, amionic, nonionic surfactants, organic fillers such as cardolites or the like.
  • vulcanizing agents for rubber such as sulfur
  • fillers making it possible to adjust the friction
  • fillers such as zircon, silicates, kaolins, silico-aluminates, sulphides, for example pyrites or others, silicas, ceramic beads, carbon black, coke, graphites, oxides, such as magnesia, iron oxides, or the like, calcium carbonate, mica, strong bases, such as potash or soda, amionic, noni
  • the shaping of the mixture can be a hot pressure molding operation or an injection molding operation.
  • the filling thus formed is then subjected to a press cooking operation; depending on the raw materials used, this operation, which aims to correctly polymerize the filling, is carried out between 180 and
  • the lining thus produced has certain drawbacks; in particular, in use at high temperature, it is subject to a swelling phenomenon, which, in certain applications, can harm the organ which it equips, as explained below.
  • the object of the present invention is to avoid these drawbacks.
  • the lining is heat treated again to reduce its swelling in use.
  • This so-called anti-swelling treatment which is carried out after all of the above conventional operations, is carried out at a temperature equal to or higher than the maximum temperature used during stabilization in an oven, preferably at a temperature above 250 ° C. , for example between 250 and 300 ° C, advantageously between 270 and 300 ° C.
  • the filling is kept at this temperature for 6 to 12 hours, advantageously under low load, for example less than 0.1 bar to avoid its buckling during the treatment.
  • This treatment can of course be carried out in an oven or in the press; in the latter case, it is preferable, in order to avoid its fogging, to allow the filling to cool in the press until its temperature has dropped below 100 ° C.
  • the invention has a particular advantage.
  • a conventional friction clutch generally comprises a reaction plate, possibly in two parts to form a damping flywheel or a flexible flywheel, fixed in rotation on a first shaft, usually a driving shaft such as the crankshaft of the combustion engine. internal of a vehicle, and supporting by its external periphery a cover to which is attached at least one pressure plate.
  • the pressure plate is integral in rotation with the cover and the reaction plate while being able to move axially under the biasing of elastic engagement means with axial action controlled by declutching means;
  • the engagement means may consist of helical springs, or one or two Belleville washers mounted in series or in parallel, subjected to the action of declutching levers forming the declutching means;
  • the engagement and disengagement means belong to the same part, for example a metal diaphragm bearing on the cover; the diaphragm can be mounted in series or in parallel with a Belleville washer to provide assistance with the declutching force, as described for example in document FR-A-2 753 758.
  • a friction disc carrying friction linings at its outer periphery, integral in rotation with a shaft, usually a driven shaft such as the input shaft of the gearbox, is interposed between the pressure plate and the reaction plate so as to be clamped together when the clutch is in the engagement position.
  • the clutch means control the axial movement of the pressure plate when they are actuated by a declutching stop by means of the declutching means.
  • a friction clutch equipped with a wear take-up device is arranged so that one of the supports of the engagement means, either the support linked directly or indirectly to the cover, or the support linked directly or indirectly to the pressure plate, is axially adjustable, a means, called compensation, being provided to achieve this offset, in association with a means, called actuation, allowing the implementation, in fact the actuation, of said compensation means and a triggering means itself controlling the actuation means by authorizing or not the entry into function of the actuation means.
  • a wear take-up device is controlled by a means, called a detection means, sensitive to the wear of the linings, directly or indirectly, that is to say for example sensitive to the position of at least 1 one of the components of the clutch influenced by said wear, said detection means acting on one of said compensation, actuation and release means.
  • the detection means of the wear take-up device takes into account the axial distance which separates the opposite faces from the reaction and pressure plates between which the linings of the friction disc are arranged, which distance s '' reduced with wear.
  • the friction linings are subjected to a high temperature, of the order of 300 ° C. and, without the anti-swelling treatment according to the invention, the linings usually swell by an amount which can reach, axially, 0, 10 millimeter: this, of course, seriously disrupts the operation of the wear take-up device, therefore of the clutch; moreover, depending on the composition of the linings, the standard deviation relating to this swelling value of 0.1 mm is of the order of 0.02 millimeter.
  • a clutch friction lining having been the subject of an anti-swelling treatment, can also be used in a reversible rotary electrical machine of the alternator-starter type as described in patent application FR 2,782,354.
  • the reaction plate belongs to a rotary drive wheel bearing the rotor of the rotating electrical machine.
  • the temperature of the friction lining will therefore be brought to an even higher temperature than in a normal machine.
  • an alternator-starter can advantageously also be provided with a wear take-up device to reduce the axial size of the alternator-starter, which will function all the better as the friction lining has undergone an anti-treatment Oregon swelling as described in the present invention.
  • the swelling of the linings in use is reduced by at least 30%, or even 90% when the linings are latex-based; in addition, the standard deviation is reduced by half.
  • the anti-swelling treatment according to the invention is all the more effective, that is to say that the swelling of the treated lining is lower the higher it is in use. , namely that its duration and the temperature of the treatment are high. This is put highlighted by examining the differential thermal analysis thermograms carried out in an inert atmosphere on samples of the same lining treated differently.
  • a typical friction lining has been produced from the above constituents; after shaping, the filling was subjected to a press cooking operation at 190 ° C., for approximately 4 minutes 30 seconds, under 250 bars and to an oven heat treatment comprising a final level of 6 hours at 250 ° vs.
  • thermogram A sample of this lining thus conventionally produced was subjected to a differential thermal analysis; the corresponding thermogram is illustrated in Figure 1; referenced ATD, we see that it consists of an endotherm EN up to 140 ° C and that above there is a strong exotherm EX. The swelling of this lining was measured at 0.1 0 mm.
  • This lining was then subjected to increasingly sophisticated complementary treatments, including the two treatments described below.
  • a first additional treatment included a final stage of 4 h at 270 ° C.
  • figure 2 On the corresponding thermogram, figure 2, there is an endotherm EN up to approximately 140 ° C, practically identical to that of figure 1; on the other hand, from 140 ° C., the exotherm EX is much weaker than that of FIG. 1, which is characteristic of greater stabilization of the material.
  • the bulge at 300 ° C is 0.07 mm.
  • thermogram of a sample of such a lining subjected to thermal analysis differential has an endotherm which extends to a temperature of at least 300 ° C.
  • the swelling at 300 ° C As an indication, to measure the swelling at 300 ° C, one can proceed as follows; there are three equidistant points on one side of the lining, at 1 20 degrees; the thicknesses are measured and recorded at the locations identified; the lining is introduced into a ventilated oven set at 300 ° C (- 0, + 2); ten minutes later, the lining is removed from the oven, it is allowed to cool for one hour and the thicknesses are measured, and recorded, in line with the markers: the swelling can then be calculated, in millimeters.
  • the friction lining described in the present invention can be advantageously used as a clutch friction disc, in particular for a motor vehicle, carrying at its outer periphery such linings and a friction clutch comprising such a friction disc and in particular equipped with 'a wear take-up device.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mechanical Operated Clutches (AREA)
  • Braking Arrangements (AREA)

Abstract

The invention concerns a method for making a friction lining, in particular for a motor vehicle friction disc, which consists in mixing raw materials such as fibres, binders, fillers; in forming said mixture; in subjecting said formed mixture to a press-curing process, which method comprises an additional step which consists in thermal treatment performed at a temperature and for a duration such that a sample of said lining, subjected to a heat differential analysis, displays an endothermy up to a temperature of at least 300 DEG C to reduce the swelling of the friction lining.

Description

"Procédé de réalisation d'une garniture de friction, notamment pour véhicule automobile." "Method for producing a friction lining, in particular for a motor vehicle."
Les figures 1 à 3 représentent chacune le thermogramme d'un échantillon de garniture de friction, défini ci-dessous, qui a été soumis à une analyse thermique différentielle.Figures 1 to 3 each show the thermogram of a friction lining sample, defined below, which has been subjected to differential thermal analysis.
Pour réaliser une garniture de friction, on procède comme suit. Les différentes matières premières sont mélangées, puis le mélange est mis en forme.To make a friction lining, proceed as follows. The different raw materials are mixed, then the mixture is shaped.
Ces matières premières peuvent comprendre, comme on le sait, des fils, des liants, des charges.These raw materials can include, as is known, threads, binders, fillers.
Les fils peuvent être constitués de fibres minérales telles que des fibres de verre, des fibres organiques, telles que des fibres de polyacrylonitrile, des fils métalliques, tels que des fils de cuivre, de laiton ou autres.The wires can consist of mineral fibers such as glass fibers, organic fibers, such as polyacrylonitrile fibers, metallic wires, such as copper, brass or other wires.
Les liants, de type thermodurcissables, peuvent être une association de résines phénoliques, de résines mélamines et de caoutchoucs.The binders, of the thermosetting type, can be a combination of phenolic resins, melamine resins and rubbers.
Les charges peuvent être des agents de vulcanisation du caoutchouc, tels que le soufre, des charges permettant d'ajuster le frottement telles que du zircon, des silicates, des kaolins, des silico-aluminates, des sulfures, par exemple pyrites ou autres, des silices, des billes de céramiques, du noir de carbone, du coke, des graphites, des oxydes, tels que magnésie, oxydes de fer, ou autres, du carbonate de calcium, du mica, des bases fortes, telles que la potasse ou la soude, des surfactants amioniques, non ioniques, des charges organiques telles que des cardolites ou autres.The fillers can be vulcanizing agents for rubber, such as sulfur, fillers making it possible to adjust the friction such as zircon, silicates, kaolins, silico-aluminates, sulphides, for example pyrites or others, silicas, ceramic beads, carbon black, coke, graphites, oxides, such as magnesia, iron oxides, or the like, calcium carbonate, mica, strong bases, such as potash or soda, amionic, nonionic surfactants, organic fillers such as cardolites or the like.
La mise en forme du mélange peut être une opération de moulage sous pression à chaud ou une opération de moulage à injection.The shaping of the mixture can be a hot pressure molding operation or an injection molding operation.
La garniture ainsi formée est ensuite soumise à une opération de cuisson sous presse ; en fonction des matières premières utilisées, cette opération, qui a pour but de polymériser correctement la garniture, est conduite entre 180 etThe filling thus formed is then subjected to a press cooking operation; depending on the raw materials used, this operation, which aims to correctly polymerize the filling, is carried out between 180 and
210°C, pendant 4 à 10 minutes, sous une pression comprise entre 150 et 300 bars. La garniture est ensuite stabilisée en étuve, à une température supérieure à 230°C pendant un temps qui peut atteindre environ 24 heures.210 ° C, for 4 to 10 minutes, under a pressure between 150 and 300 bars. The filling is then stabilized in an oven, at a temperature above 230 ° C for a time which can reach approximately 24 hours.
La garniture ainsi réalisée présente certains inconvénients ; notamment, en utilisation à haute température, elle est sujette à un phénomène de gonflement, ce qui, dans certaines applications, peut nuire à l'organe qu'elle équipe, comme expliqué ci-dessous.The lining thus produced has certain drawbacks; in particular, in use at high temperature, it is subject to a swelling phenomenon, which, in certain applications, can harm the organ which it equips, as explained below.
La présente invention a pour but d'éviter ces inconvénients.The object of the present invention is to avoid these drawbacks.
Suivant l'invention, la garniture est traitée une nouvelle fois thermiquement pour réduire son gonflement en utilisation. Ce traitement, dit anti-gonflement, qui est effectué après toutes les opérations classiques ci-dessus, est conduit à une température égale ou supérieure à la température maximale utilisée lors de la stabilisation en étuve, de préférence à une température supérieure à 250°C, par exemple comprise entre 250 et 300°C, avantageusement entre 270 et 300°C. La garniture est maintenue à cette température pendant 6 à 12 heures, avantageusement sous faible charge, par exemple inférieure à 0,1 bar pour éviter son voilage pendant le traitement.According to the invention, the lining is heat treated again to reduce its swelling in use. This so-called anti-swelling treatment, which is carried out after all of the above conventional operations, is carried out at a temperature equal to or higher than the maximum temperature used during stabilization in an oven, preferably at a temperature above 250 ° C. , for example between 250 and 300 ° C, advantageously between 270 and 300 ° C. The filling is kept at this temperature for 6 to 12 hours, advantageously under low load, for example less than 0.1 bar to avoid its buckling during the treatment.
Ce traitement peut bien entendu être effectué en étuve ou sous presse ; dans ce dernier cas, on préfère, pour éviter son voilage, laisser la garniture refroidir sous presse tant que sa température n'est pas descendue en dessous de 100°C.This treatment can of course be carried out in an oven or in the press; in the latter case, it is preferable, in order to avoid its fogging, to allow the filling to cool in the press until its temperature has dropped below 100 ° C.
Dans l'application à une garniture pour disque de friction d'embrayage associé à un mécanisme d'embrayage pour constituer un embrayage à friction, notamment pour véhicule automobile, l'invention présente un avantage particulier.In the application to a lining for a clutch friction disc associated with a clutch mechanism to constitute a friction clutch, in particular for a motor vehicle, the invention has a particular advantage.
Un embrayage à friction classique comporte généralement un plateau de réaction, éventuellement en deux parties pour formation d'un volant amortisseur ou d'un volant flexible, calé en rotation sur un premier arbre, usuellement un arbre menant tel que le vilebrequin du moteur à combustion interne d'un véhicule, et supportant par sa périphérie externe un couvercle auquel est attaché au moins un plateau de pression.A conventional friction clutch generally comprises a reaction plate, possibly in two parts to form a damping flywheel or a flexible flywheel, fixed in rotation on a first shaft, usually a driving shaft such as the crankshaft of the combustion engine. internal of a vehicle, and supporting by its external periphery a cover to which is attached at least one pressure plate.
Le plateau de pression est solidaire en rotation du couvercle et du plateau de réaction tout en pouvant se déplacer axialement sous la sollicitation de moyens embrayeurs élastiques à action axiale commandés par des moyens débrayeurs ; les moyens embrayeurs peuvent consister en des ressorts hélicoïdaux, ou en une ou deux rondelles Belleville montées en série ou en parallèle, soumis à l'action de leviers de débrayage formant les moyens débrayeurs ; généralement, les moyens embrayeurs et débrayeurs appartiennent à une même pièce, par exemple un diaphragme métallique prenant appui sur le couvercle ; le diaphragme peut être monté en série ou en parallèle avec une rondelle Belleville pour assurer une assistance de l'effort de débrayage, comme décrit par exemple dans le document FR-A- 2 753 758.The pressure plate is integral in rotation with the cover and the reaction plate while being able to move axially under the biasing of elastic engagement means with axial action controlled by declutching means; the engagement means may consist of helical springs, or one or two Belleville washers mounted in series or in parallel, subjected to the action of declutching levers forming the declutching means; generally, the engagement and disengagement means belong to the same part, for example a metal diaphragm bearing on the cover; the diaphragm can be mounted in series or in parallel with a Belleville washer to provide assistance with the declutching force, as described for example in document FR-A-2 753 758.
Un disque de friction, portant des garnitures de friction à sa périphérie externe, solidaire en rotation d'un arbre, usuellement un arbre mené tel que l'arbre d'entrée de la boîte de vitesses, est intercalé entre le plateau de pression et le plateau de réaction de façon à être serré entre eux lorsque l'embrayage est en position d'engagement. Les moyens embrayeurs commandent le déplacement axial du plateau de pression lorsqu'ils sont actionnés par une butée de débrayage par l'intermédiaire des moyens débrayeurs.A friction disc, carrying friction linings at its outer periphery, integral in rotation with a shaft, usually a driven shaft such as the input shaft of the gearbox, is interposed between the pressure plate and the reaction plate so as to be clamped together when the clutch is in the engagement position. The clutch means control the axial movement of the pressure plate when they are actuated by a declutching stop by means of the declutching means.
Au cours de la durée de vie d'un tel embrayage, les garnitures de friction ainsi que les contre-matériaux, plateau de pression et plateau de réaction, s'usent, ce qui provoque une variation de la position du plateau de pression et celles des moyens embrayeurs à action axiale et de la butée de débrayage, d'où il s'ensuit, d'une part, une variation de la force de serrage du disque de friction entre les plateaux de pression et de réaction en raison des modifications des conditions de travail des moyens débrayeurs, et, d'autre part, que la force nécessaire pour débrayer s'en trouve affectée. En dotant un tel embrayage d'un dispositif de rattrapage d'usure, on évite ces inconvénients, les moyens embrayeurs, ainsi que la butée de débrayage, usuellement en appui constant sur les moyens débrayeurs, occupant la même position lorsque l'embrayage est en position d'engagement.During the service life of such a clutch, the friction linings as well as the counter materials, pressure plate and reaction plate, wear, which causes a variation in the position of the pressure plate and those axially acting engagement means and the clutch release bearing, from which it follows, on the one hand, a variation in the clamping force of the friction disc between the pressure and reaction plates due to the modifications of the working conditions of the declutching means, and, on the other hand, that the force necessary to declutch is affected. By providing such a clutch with a wear take-up device, these drawbacks are avoided, the clutch means, as well as the clutch release bearing, usually in constant support on the clutch means, occupying the same position when the clutch is in engagement position.
Un embrayage à friction équipé d'un dispositif de rattrapage d'usure est agencé en sorte que l'un des appuis des moyens embrayeurs, que ce soit l'appui lié directement ou indirectement au couvercle, ou l'appui lié directement ou indirectement au plateau de pression, est décalable axialement, un moyen, dit de compensation, étant prévu pour réaliser ce décalage, en association avec un moyen, dit d'actionnement, permettant la mise en oeuvre, en fait l'actionnement, dudit moyen de compensation et un moyen de déclenchement commandant lui-même le moyen d'actionnement en autorisant ou non l'entrée en fonction du moyen d'actionnement. Bien entendu, un dispositif de rattrapage d'usure est piloté par un moyen, dit de détection, sensible à l'usure des garnitures, directement ou indirectement, c'est-à-dire par exemple sensible à la position d'au moins l'un des constituants de l'embrayage influencée par ladite usure, ledit moyen de détection agissant sur l'un desdits moyens de compensation, d'actionnement et de déclenchement.A friction clutch equipped with a wear take-up device is arranged so that one of the supports of the engagement means, either the support linked directly or indirectly to the cover, or the support linked directly or indirectly to the pressure plate, is axially adjustable, a means, called compensation, being provided to achieve this offset, in association with a means, called actuation, allowing the implementation, in fact the actuation, of said compensation means and a triggering means itself controlling the actuation means by authorizing or not the entry into function of the actuation means. Of course, a wear take-up device is controlled by a means, called a detection means, sensitive to the wear of the linings, directly or indirectly, that is to say for example sensitive to the position of at least 1 one of the components of the clutch influenced by said wear, said detection means acting on one of said compensation, actuation and release means.
On connaît différents types de dispositif de rattrapage d'usure, décrits par exemple, dans les documents FR-A-2 753 503, GB-A-2 294 983, GB-A- 2 294 301 , US-A-5 564 541 , FR-A-2 599 446 ou autres.Different types of wear take-up device are known, described for example in the documents FR-A-2 753 503, GB-A-2 294 983, GB-A- 2 294 301, US-A-5 564 541 , FR-A-2 599 446 or others.
Il est aisé de comprendre que le moyen de détection du dispositif de rattrapage d'usure prend en compte la distance axiale qui sépare les faces en regard des plateaux de réaction et de pression entre lesquelles sont disposées les garnitures du disque de friction, laquelle distance s'amenuise avec l'usure. En fonctionnement, les garnitures de friction sont soumises à une température élevée, de l'ordre de 300°C et, sans le traitement anti-gonflement selon l'invention, usuellement les garnitures gonflent d'une quantité pouvant atteindre, axialement, 0, 10 millimètre : ceci, bien évidemment, perturbe gravement le fonctionnement du dispositif de rattrapage d'usure, donc de l'embrayage ; par ailleurs, en fonction de la composition des garnitures, l'écart type afférent à cette valeur de gonflement de 0, 1 0 millimètre est de l'ordre de 0,02 millimètre.It is easy to understand that the detection means of the wear take-up device takes into account the axial distance which separates the opposite faces from the reaction and pressure plates between which the linings of the friction disc are arranged, which distance s '' reduced with wear. In operation, the friction linings are subjected to a high temperature, of the order of 300 ° C. and, without the anti-swelling treatment according to the invention, the linings usually swell by an amount which can reach, axially, 0, 10 millimeter: this, of course, seriously disrupts the operation of the wear take-up device, therefore of the clutch; moreover, depending on the composition of the linings, the standard deviation relating to this swelling value of 0.1 mm is of the order of 0.02 millimeter.
Avantageusement, une garniture de friction d'embrayage ayant fait l'objet d'un traitement anti-regonflement, peut égalemant être utilisée dans une machine électrique tournante réversible de type alternateur-démarreur telle que décrite dans la demande de brevet FR 2,782,354. En effet; dans ce type de machine, le plateau de réaction appartient à un volant d'entraînement en rotation portant le rotor de la machine électrique tournante. La température de la garniture de friction sera donc portée à une température encore plus élevée que dans une machine normale. De plus, un alternateur-démarreur peut avantageusement également être doté d'un dispositif de rattrapage d'usure pour réduire l'encombrement axial de l'alternateur-démarreur, qui fonctionnera d'autant mieux que la garniture de friction aura subi un traîtement anti-regonflement tel que décrit dans la présente invention.Advantageously, a clutch friction lining having been the subject of an anti-swelling treatment, can also be used in a reversible rotary electrical machine of the alternator-starter type as described in patent application FR 2,782,354. Indeed; in this type of machine, the reaction plate belongs to a rotary drive wheel bearing the rotor of the rotating electrical machine. The temperature of the friction lining will therefore be brought to an even higher temperature than in a normal machine. In addition, an alternator-starter can advantageously also be provided with a wear take-up device to reduce the axial size of the alternator-starter, which will function all the better as the friction lining has undergone an anti-treatment Oregon swelling as described in the present invention.
Grâce au traitement anti-gonflement selon l'invention, le gonflement des garnitures en utilisation, mesuré axialement, est réduit d'au moins 30 %, voire de 90 % lorsque les garnitures sont à base de latex ; de plus, l'écart type est réduit de moitié.Thanks to the anti-swelling treatment according to the invention, the swelling of the linings in use, measured axially, is reduced by at least 30%, or even 90% when the linings are latex-based; in addition, the standard deviation is reduced by half.
L'efficacité du traitement anti-gonflement selon l'invention peut s'expliquer par le résultat de nombreux essais effectués.The effectiveness of the anti-swelling treatment according to the invention can be explained by the result of numerous tests carried out.
Ces essais ont montré en particulier qu'à la température d'utilisation, de l'ordre de 300°C, les garnitures non traitées conformément à l'invention perdent du poids et le gonflement est d'autant plus important que la perte de poids est importante ; dès lors, grâce au traitement anti-gonflement, la perte de poids de la garniture a lieu lors de sa fabrication et le traitement antigonflement est avantageusement conduit en sorte de faire perdre à la garniture le poids qu'elle aurait perdu en utilisation si elle n'avait pas subi ce traitement anti-gonflement.These tests have shown in particular that at the operating temperature, of the order of 300 ° C., the linings not treated in accordance with the invention lose weight and the swelling is all the more important as the weight loss is important; therefore, thanks to the anti-swelling treatment, the weight loss of the filling takes place during its manufacture and the anti-swelling treatment is advantageously carried out so as to make the filling lose the weight that it would have lost in use if it did not had not undergone this anti-swelling treatment.
Des essais ont montré également que, en utilisation, une garniture classique voit sa porosité augmenter ; cet accroissement de porosité correspond à une élimination des liants à faible masse moléculaire, à une réduction des contraintes et à une stabilisation du réseau ; le traitement antigonflement selon l'invention donne à la garniture une porosité quasiment stable qui n'évoluera pas, ou très peu, en utilisation et son gonflement s'en trouvera très limité.Tests have also shown that, in use, a conventional packing sees its porosity increasing; this increase in porosity corresponds to an elimination of low molecular weight binders, a reduction in stresses and a stabilization of the network; the anti-swelling treatment according to the invention gives the lining an almost stable porosity which will not change, or very little, in use and its swelling will be very limited.
L'expérience a montré que le traitement anti-gonflement selon l'invention est d'autant plus efficace, c'est-à-dire que le gonflement de la garniture traitée est d'autant moins élevé en utilisation, qu'il est puissant, à savoir que sa durée et la température du traitement sont élevées. Ceci est mis en évidence par l'examen des thermogrammes d'analyse thermiques différentielles effectués en atmosphère inerte sur des échantillons d'une même garniture traités différemment.Experience has shown that the anti-swelling treatment according to the invention is all the more effective, that is to say that the swelling of the treated lining is lower the higher it is in use. , namely that its duration and the temperature of the treatment are high. This is put highlighted by examining the differential thermal analysis thermograms carried out in an inert atmosphere on samples of the same lining treated differently.
A titre d'exemple, on a réalisé une garniture de friction type à partir des constituants ci-dessus ; après mise en forme, la garniture a été soumise à une opération de cuisson sous presse à 1 90°C, pendant environ 4 minutes 30 secondes, sous 250 bars et à un traitement thermique en étuve comportant un palier final de 6 h à 250°C.By way of example, a typical friction lining has been produced from the above constituents; after shaping, the filling was subjected to a press cooking operation at 190 ° C., for approximately 4 minutes 30 seconds, under 250 bars and to an oven heat treatment comprising a final level of 6 hours at 250 ° vs.
Un échantillon de cette garniture ainsi réalisée classiquement a été soumis à une analyse thermique différentielle ; le thermogramme correspondant est illustré par la figure 1 ; référencé ATD, on voit qu'il est constitué d'un endotherme EN jusqu'à 140°C et qu'au dessus on a un fort exotherme EX. Le regonflement de cette garniture a été mesuré à 0.1 0 mm.A sample of this lining thus conventionally produced was subjected to a differential thermal analysis; the corresponding thermogram is illustrated in Figure 1; referenced ATD, we see that it consists of an endotherm EN up to 140 ° C and that above there is a strong exotherm EX. The swelling of this lining was measured at 0.1 0 mm.
On a ensuite soumis cette garniture à des traitements complémentaires de plus en plus poussés dont les deux traitements décrits ci-dessous .This lining was then subjected to increasingly sophisticated complementary treatments, including the two treatments described below.
Un premier traitement complémentaire comportait un palier final de 4 h à 270°C. Sur le thermogramme correspondant, figure 2, on a un endotherme EN jusqu'à environ 140°C, pratiquement identique à celui de la figure 1 ; en revanche, à partir de 140°C, l'exotherme EX est beaucoup plus faible que celui de la figure 1 , ce qui est caractéristique d'une plus grande stabilisation du matériau. Avec ce traitement, le regonflement à 300°C est de 0,07 mm.A first additional treatment included a final stage of 4 h at 270 ° C. On the corresponding thermogram, figure 2, there is an endotherm EN up to approximately 140 ° C, practically identical to that of figure 1; on the other hand, from 140 ° C., the exotherm EX is much weaker than that of FIG. 1, which is characteristic of greater stabilization of the material. With this treatment, the bulge at 300 ° C is 0.07 mm.
Un second traitement complémentaire a été plus poussé que celui décrit précédemment : il comportait un palier final de 8 h à 270°C. Sur le thermogramme correspondant, figure 3, on a un endotherme EN jusqu'à environ 650°C et pratiquement plus d'exotherme. Le matériau est donc très bien stabilisé, ce qui se traduit par un regonflement à 300°C extrêmement faible, de l'ordre de 0,01 mm, ce qui assure une sécurité totale du fonctionnement des rattrapages de jeu automatiques.A second additional treatment was further developed than that described above: it included a final stage of 8 h at 270 ° C. On the corresponding thermogram, Figure 3, we have an EN endotherm up to about 650 ° C and practically more exotherm. The material is therefore very well stabilized, which results in an extremely low swelling at 300 ° C, of the order of 0.01 mm, which ensures total safety in the operation of the automatic play compensations.
Ainsi, une caractéristique importante d'une garniture de friction ayant subi le traitement anti-gonflement selon l'invention est que le thermogramme d'un échantillon d'une telle garniture soumis à une analyse thermique différentielle présente un endotherme qui s'étend jusqu'à une température d'au moins 300°C.Thus, an important characteristic of a friction lining having undergone the anti-swelling treatment according to the invention is that the thermogram of a sample of such a lining subjected to thermal analysis differential has an endotherm which extends to a temperature of at least 300 ° C.
A titre indicatif, pour mesurer le gonflement à 300°C, on peut procéder comme suit ; on repère sur une face de la garniture trois points equidistants, à 1 20 degrés ; on mesure et on enregistre les épaisseurs aux endroits repérés ; on introduit la garniture dans une étuve ventilée réglée à 300°C (- 0, + 2) ; dix minutes après, on sort la garniture de l'étuve, on la laisse refroidir pendant une heure et on mesure, et on enregistre, les épaisseurs au droit des repères : le gonflement peut alors être calculé, en millimètre. La garniture de friction décrite dans la présente invention peut être avantageusement utilisée comme disque de friction d'embrayage, en particulier pour véhicule automobile, portant à sa périphérie externe de telles garnitures et un embrayage à friction comportant un tel disque de friction et notamment équipé d'un dispositif de rattrapage d'usure. As an indication, to measure the swelling at 300 ° C, one can proceed as follows; there are three equidistant points on one side of the lining, at 1 20 degrees; the thicknesses are measured and recorded at the locations identified; the lining is introduced into a ventilated oven set at 300 ° C (- 0, + 2); ten minutes later, the lining is removed from the oven, it is allowed to cool for one hour and the thicknesses are measured, and recorded, in line with the markers: the swelling can then be calculated, in millimeters. The friction lining described in the present invention can be advantageously used as a clutch friction disc, in particular for a motor vehicle, carrying at its outer periphery such linings and a friction clutch comprising such a friction disc and in particular equipped with 'a wear take-up device.

Claims

REVENDICATIONS
1. Procédé de réalisation d'une garniture de friction, notamment de disque de friction, en particulier pour véhicule automobile, consistant à mélanger des matières premières telles que fibres, liants, charges, à mettre en forme ledit mélange, à soumettre le mélange ainsi formé à une opération de cuisson sous presse, caractérisé en ce qu'il comporte une étape complémentaire consistant en un traitement thermique réalisé à une température et pendant une durée telles qu'un échantillon de cette garniture, soumis à une analyse thermique différentielle, présente un endotherme qui s'étend jusqu'à une température d'au moins 300°C, pour réduire le regonflement de ladite garniture de friction.1. Method for producing a friction lining, in particular a friction disc, in particular for a motor vehicle, consisting of mixing raw materials such as fibers, binders, fillers, shaping said mixture, subjecting the mixture as well formed in a press cooking operation, characterized in that it comprises an additional step consisting of a heat treatment carried out at a temperature and for a duration such that a sample of this filling, subjected to a differential thermal analysis, presents a endotherm which extends up to a temperature of at least 300 ° C, to reduce the swelling of said friction lining.
2. Procédé selon la revendication 1 , caractérisé par le fait que la température du traitement thermique complémentaire est réalisé à une température comprise entre 250 et 300°C2. Method according to claim 1, characterized in that the temperature of the additional heat treatment is carried out at a temperature between 250 and 300 ° C.
3. Procédé selon la revendication 1 ou 2, caractérisé par le fait que la température du traitement thermique complémentaire est réalisé pendant un temps compris entre 6 et 12 heures.3. Method according to claim 1 or 2, characterized in that the temperature of the additional heat treatment is carried out for a time between 6 and 12 hours.
4. Procédé selon l'une quelconque des revendications précédentes caractérisé par le fait qu'une étape de stabilisation en étuve des garnitures de friction est prévue entre l'opération de cuisson sous presse et le traitement thermique complémentaire anti-gonflement.4. Method according to any one of the preceding claims, characterized in that a stage of stabilization in the oven of the friction linings is provided between the press cooking operation and the anti-swelling complementary heat treatment.
5. Procédé selon la revendication 1 caractérisée en ce que les liants sont thermodurcissables.5. Method according to claim 1 characterized in that the binders are thermosetting.
6. Procédé selon l'une quelconque des revendications 1 à 4, caractérisé par le fait que, à la sortie de l'étape complémentaire de traitement thermique d'anti-regonflement, la garniture est refroidie sous presse jusqu'à ce que sa température ait atteint moins de 100°C. 6. Method according to any one of claims 1 to 4, characterized in that, at the end of the additional heat treatment step of anti-swelling, the lining is cooled in press until its temperature has reached less than 100 ° C.
7. Procédé selon la revendication 1 , caractérisé par le fait que la température du traitement anti-gonflement est comprise entre 270 et 300°C.7. Method according to claim 1, characterized in that the temperature of the anti-swelling treatment is between 270 and 300 ° C.
8. Procédé selon l'une quelconque des revendications 1 à 7, caractérisé par le fait que le traitement anti-gonflement est réalisé sous charge, en étuve ou sous presse.8. Method according to any one of claims 1 to 7, characterized in that the anti-swelling treatment is carried out under load, in an oven or in a press.
9. Procédé selon la revendication 8, caractérisé par le fait que la charge est inférieure à 0,1 bar.9. Method according to claim 8, characterized in that the load is less than 0.1 bar.
10. Procédé selon la revendication 1 , caractérisé par le fait que la mise en forme du mélange est une opération de moulage sous pression à chaud ou une opération de moulage à injection.10. Method according to claim 1, characterized in that the shaping of the mixture is a hot pressure molding operation or an injection molding operation.
11. Procédé selon l'une des revendications 1 à 10, caractérisé par le fait que l'opération de cuisson sous presse est conduite entre 180 et 210°C, pendant 4 à 10 minutes, sous 150 à 300 bars.11. Method according to one of claims 1 to 10, characterized in that the press cooking operation is carried out between 180 and 210 ° C, for 4 to 10 minutes, at 150 to 300 bars.
12. Procédé selon la revendication 4, caractérisé par le fait que l'opération de stabilisation en étuve est réalisée à température supérieure à 230°C pendant un temps pouvant atteindre environ 24 heures.12. Method according to claim 4, characterized in that the stabilization operation in an oven is carried out at a temperature above 230 ° C for a time which can reach approximately 24 hours.
13. Garniture de friction obtenu selon un procédé décrit selon l'une quelconque des revendications précédentes caractérisée par le fait qu'un échantillon de cette garniture soumis à une analyse thermique différentielle, présente un endotherme qui s'étend jusqu'à une température d'au moins 300°C.13. Friction lining obtained according to a process described according to any one of the preceding claims, characterized in that a sample of this lining subjected to differential thermal analysis has an endotherm which extends up to a temperature of at least 300 ° C.
14. Garniture de friction selon la revendication 13, caractérisée par le fait qu'elle est en forme de plots ou de segments destinés à équiper un disque de friction d'embrayage. 14. Friction lining according to claim 13, characterized in that it is in the form of studs or segments intended to equip a clutch friction disc.
15. Garniture de friction selon la revendication 13, caractérisée par le fait qu'elle est en forme de couronne destinée à équiper un disque de friction d'embrayage.15. Friction lining according to claim 13, characterized in that it is in the form of a crown intended to equip a clutch friction disc.
16. Disque de friction d'embrayage portant à sa périphérie externe des garnitures de friction, caractérisé par le fait que les garnitures de friction sont selon l'une des revendications 14 ou 15.16. Clutch friction disc carrying friction linings at its outer periphery, characterized in that the friction linings are according to one of claims 14 or 15.
17. Embrayage à friction, du genre comportant un plateau de réaction supportant par sa périphérie externe un couvercle auquel est attaché au moins un plateau de pression, un disque de friction étant intercalé entre le plateau de réaction et le plateau de pression, caractérisé par le fait que le disque de friction est selon la revendication 16.17. Friction clutch, of the type comprising a reaction plate supporting by its external periphery a cover to which at least one pressure plate is attached, a friction disc being interposed between the reaction plate and the pressure plate, characterized by fact that the friction disc is according to claim 16.
18. Embrayage à friction, selon la revendication 17, caractérisé par le fait qu'il est équipé d'un dispositif de rattrapage d'usure.18. Friction clutch according to claim 17, characterized in that it is equipped with a wear take-up device.
19. Embrayage à friction, selon la revendication 16 ou 17, caractérisé en ce que le plateau de réaction appartient à un volant d'entraînement portant le rotor d'une machine électrique tournante. 19. Friction clutch according to claim 16 or 17, characterized in that the reaction plate belongs to a drive wheel carrying the rotor of a rotary electric machine.
PCT/FR2000/003556 1999-12-28 2000-12-15 Method for producing a friction lining, in particular for motor vehicle WO2001048391A1 (en)

Priority Applications (2)

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DE10084293.3T DE10084293B4 (en) 1999-12-28 2000-12-15 Method for producing a friction lining, in particular for motor vehicles
JP2001548874A JP2003518596A (en) 1999-12-28 2000-12-15 Realization method of friction lining especially for automobile

Applications Claiming Priority (2)

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FR9916580A FR2802999A1 (en) 1999-12-28 1999-12-28 Making friction lining for vehicle clutch by pressure curing mixture of fibers, binders and fillers and heat treating lining to reduce swelling in use
FR99/16580 1999-12-28

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EP0409495A1 (en) * 1989-07-19 1991-01-23 BP Chemicals Limited Compositions for friction elements
DE4239441A1 (en) * 1992-11-24 1994-05-26 Fichtel & Sachs Ag Low-density friction materials, esp. for dry clutch linings - by press-moulding and heating a blank contg. gas-producing, density-reducing additives, e.g., bicarbonate, organic blowing agent, water, etc.
FR2706556A1 (en) * 1993-06-18 1994-12-23 Luk Lamellen & Kupplungsbau Friction lining
DE4431642A1 (en) * 1993-09-16 1995-03-23 Luk Lamellen & Kupplungsbau Friction lining
FR2753503A1 (en) * 1996-09-17 1998-03-20 Valeo Friction clutch for motor vehicles
FR2753758A1 (en) * 1996-09-06 1998-03-27 Valeo Friction clutch, exp for motor vehicle
EP0965770A1 (en) * 1998-06-17 1999-12-22 Valeo Method of fabrication of a friction material and in particular of a friction ring for a friction disc of a clutch and friction ring of a clutch

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FR2599446B1 (en) 1986-06-03 1988-08-05 Valeo CONTINUOUSLY WEARING FRICTION CLUTCH
GB2294301B (en) 1991-11-26 1996-07-03 Luk Lamellen & Kupplungsbau Friction clutch
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EP0859918B1 (en) * 1996-09-06 2002-11-27 Valeo Friction clutch with low disengaging force
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2379563A1 (en) * 1977-02-02 1978-09-01 Porter Co Inc H K COMPOSITION FOR FRICTION ELEMENTS FREE OF ASBESTOS AND THUS OBTAINED ELEMENTS
EP0409495A1 (en) * 1989-07-19 1991-01-23 BP Chemicals Limited Compositions for friction elements
DE4239441A1 (en) * 1992-11-24 1994-05-26 Fichtel & Sachs Ag Low-density friction materials, esp. for dry clutch linings - by press-moulding and heating a blank contg. gas-producing, density-reducing additives, e.g., bicarbonate, organic blowing agent, water, etc.
FR2706556A1 (en) * 1993-06-18 1994-12-23 Luk Lamellen & Kupplungsbau Friction lining
DE4431642A1 (en) * 1993-09-16 1995-03-23 Luk Lamellen & Kupplungsbau Friction lining
FR2753758A1 (en) * 1996-09-06 1998-03-27 Valeo Friction clutch, exp for motor vehicle
FR2753503A1 (en) * 1996-09-17 1998-03-20 Valeo Friction clutch for motor vehicles
EP0965770A1 (en) * 1998-06-17 1999-12-22 Valeo Method of fabrication of a friction material and in particular of a friction ring for a friction disc of a clutch and friction ring of a clutch

Also Published As

Publication number Publication date
FR2802999A1 (en) 2001-06-29
DE10084293B4 (en) 2019-08-01
FR2803000A1 (en) 2001-06-29
JP2003518596A (en) 2003-06-10
DE10084293T1 (en) 2002-03-28
FR2803000B1 (en) 2002-12-27

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