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
  • F16D13/00—Friction clutches
  • F16D13/58—Details
  • F16D13/75—Features relating to adjustment, e.g. slack adjusters
  • F16D13/757—Features relating to adjustment, e.g. slack adjusters the adjusting device being located on or inside the clutch cover, e.g. acting on the diaphragm or on the pressure plate
• • 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
  • F16D13/00—Friction clutches
  • F16D13/58—Details
  • F16D13/70—Pressure members, e.g. pressure plates, for clutch-plates or lamellae; Guiding arrangements for pressure members
  • F16D13/71—Pressure members, e.g. pressure plates, for clutch-plates or lamellae; Guiding arrangements for pressure members in which the clutching pressure is produced by springs only
• • 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
  • F16D13/00—Friction clutches
  • F16D13/58—Details
  • F16D13/70—Pressure members, e.g. pressure plates, for clutch-plates or lamellae; Guiding arrangements for pressure members
  • F16D2013/706—Pressure members, e.g. pressure plates, for clutch-plates or lamellae; Guiding arrangements for pressure members the axially movable pressure plate is supported by leaf springs

Definitions

• the present invention relates to a friction clutch.
• the invention relates more particularly to a friction clutch, in particular for a motor vehicle, which is equipped with a device for compensating for wear due in particular to the wear of the friction linings, the wear take-up device intervening automatically at as the friction linings wear.
• a friction clutch of conventional design generally comprises a reaction plate, possibly in two parts, for the formation of a damping flywheel or of a flexible flywheel, which is locked in rotation on a first shaft, usually a driving shaft such as the crankshaft of the vehicle combustion engine, and supporting by its external periphery a cover to which is attached, with axial mobility, 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 stress of axially acting engagement means which are controlled by declutching means.
• the declutching means can consist of helical springs, or two Belleville washers mounted in series, subjected to the action of declutching levers forming the declutching means.
• the engagement and disengagement means belong to the same part, for example to a metal diaphragm bearing on the cover, the diaphragm being able to be mounted in series or in parallel with a Belleville washer to provide assistance to declutching effort.
• At least one 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 between these two plates when the clutch is in the engagement position to transmit the torque from the drive shaft to the driven shaft.
• the friction linings are mounted on an axially elastic support which is rigidly or resiliently coupled to a hub wedged in rotation on the driven shaft. Thanks to this arrangement, the friction disc assists the diaphragm during the clutch release operation.
• the engagement means, the cover and the pressure plate belong to a unitary assembly called friction clutch mechanism.
• 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.
• the clutch release bearing can be controlled mechanically, hydraulically or electrically.
• the control can be of the manual, automatic or semi-automatic type.
• a friction clutch in particular for a motor vehicle, of the type comprising a rear cover, a front pressure plate which is linked in rotation to the cover and which can move axially relative to the cover while being subjected to the action of elastic means recalling the pressure plate axially towards the cover, and elastic engagement means with axial action axially interposed and acting between on the one hand the cover and, on the other hand, the pressure plate via zones of support formed on an adjustment ring belonging to a wear compensation device with ramps which is interposed axially between the engagement means and the pressure plate.
• the adjustment ring belonging to the wear take-up device is mounted to rotate about its axis relative to the friction plate, under the control of a mechanism of the ratchet and worm + type in order to compensate for the wear phenomena mentioned above.
• the invention provides a friction clutch of the type mentioned above, characterized in that at least one hook is provided elastic carried by the pressure plate which permanently biases the adjusting ring, axially from back to front in the direction of the pressure plate, to maintain the ramps of the device in mutual contact. Thanks to the invention, a simple and effective solution is obtained. According to other characteristics of the invention:
• the engagement means consist of an elastic diaphragm having a peripheral portion, radially external, in the form of a Belleville washer, the external radial periphery of which cooperates with the bearing zones, and in that the elastic hook has, in axial section, general shape of a hairpin and has two branches, of generally transverse orientation linked together by a central connecting elbow, including a front branch for fixing the hook on the pressure plate and a rear branch which acts directly or indirectly, on the adjusting ring to urge the latter axially from back to front in the direction of the pressure plate;
• the adjustment ring comprises a radially inner part and of generally transverse orientation, the front transverse face of which comprises ramps which cooperate with the pressure plate and the front transverse face of which compotes the bearing zones;
• the adjustment ring comprises a radially outer part and of generally axial orientation which extends axially from rear to front from the outer radial periphery of the radially inner part of the adjustment ring;
• the free end section of the rear branch of the elastic hook comprises a fulcrum which cooperates with a portion opposite the front transverse face of the external periphery of the Belleville washer;
• the free end section of the rear branch of the elastic hook has a rounded profile, the convexity of which is oriented axially towards the front;
• the point of contact between said rounded profile and the Belleville washer is arranged radially substantially in line with the radius of the support zones;
• the free end section of the rear branch of the elastic hook comprises a fulcrum which cooperates with a rear transverse annular face of the adjustment ring;
• Said rear transverse annular face belongs to a collar which extends radially outwards from the free front end of the radially external part of the adjustment ring;
• the free end section of the rear branch of the elastic hook has a rounded profile, the convexity of which is oriented axially towards the front;
• the front branch of the elastic hook is fixed to the pressure plate by a rivet which extends axially through the pressure plate;
• the rivet is located radially outside with respect to said fulcrum;
• the front branch of the elastic hook is shorter than its rear branch and the fixing rivet is located in the vicinity of the internal radial free end of the front branch;
• the diaphragm is supported by the internal radial periphery of its Belleville washer against an annular boss formed in the internal face of the cover which is arranged radially inward relative to said fulcrum;
• the Belleville washer is extended radially inwards by a central part fragmented into radial fingers by slots for the formation of declutching means;
• the clutch comprises a series of elastic hooks distributed angularly in a regular manner
• the elastic hooks belong to a common washer carried by the internal front face of the cover.
• FIG. 1 is an axial sectional view which illustrates the main components of a first embodiment of a clutch mechanism produced in accordance with the teachings of the invention and in which the friction clutch is illustrated in a position engaged;
• FIG. 1 is a view similar to that of Figure 1 in which the clutch is illustrated in the disengaged position;
• - Figures 3 and 4 are views similar to those of Figures 1 and 2 which illustrate a second embodiment of the invention.
• the clutch mechanism 10 illustrated in the figures is of the type described and represented in French patent application No. 96 15865, the content of which may be referred to in detail for the general structure of the clutch and more particularly that of its known means for automatically adjusting wear with ramps.
• the part of the clutch mechanism according to the invention illustrated in FIGS. 1 and 2 corresponds in particular to the lower part of FIG. 21 of French patent application No. 96 15865 and FR-A-2 753 503.
• the clutch with friction 10 is of the diaphragm type 12 and it includes a rear cover 14 which is a metal piece of pressed sheet metal of general shape of revolution around the central axis XX of the clutch.
• the diaphragm 12 of frustoconical shape in the free state, comprises a peripheral part in the shape of a Belleville washer 24 extended radially towards the center by a central part fragmented into radial fingers 20 by blind slots opening into the central opening of the diaphragm 12 delimited by the internal radial ends 18 of the fingers 20.
• the bottoms of the slots are located at the internal periphery of the Belleville washer of the diaphragm and constitute enlarged orifices intended to be crossed by balusters or legs carrying a secondary tilting support described below.
• the Belleville washer 24 of the diaphragm constitutes clutch engagement means, while the fingers 20 constitute clutch release means of the diaphragm.
• the cover 14 has a bottom 16 in the form of a generally transverse orientation wall, that is to say perpendicular to the axis XX of the clutch mechanism, and means (not shown) for fixing the cover 14 to a reaction plate (not shown).
• the clutch illustrated in the figures is of the pushed type, that is to say it is necessary, using a clutch release bearing (not shown), to act by pushing axially from back to front (c '' i.e. from right to left considering the figures) on the internal radial ends 18 of the fingers 20 of the diaphragm 12 to disengage (disengage) the clutch 10.
• the bottom 16 of the cover 14 carries a primary support 22 which, in the embodiment illustrated in the figures, is an annular stamp produced in the bottom 16 of the cover 14 which projects axially towards the rear and, from on the other hand, opposite the primary support 22, a secondary support which is for example produced in the form of profiled heads of balusters (not shown in the figures) or any other means such as a rolled crown carried by balusters .
• a primary support 22 which, in the embodiment illustrated in the figures, is an annular stamp produced in the bottom 16 of the cover 14 which projects axially towards the rear and, from on the other hand, opposite the primary support 22, a secondary support which is for example produced in the form of profiled heads of balusters (not shown in the figures) or any other means such as a rolled crown carried by balusters .
• the secondary supports can be those described in document FR-A-2 456 877.
• the diaphragm 12 by the internal periphery of its Belleville washer 24, is thus pivotally mounted between the primary 22 and secondary supports.
• the diaphragm 12 is in contact with support zones 28 which will be described later.
• the invention is not limited to the case of a friction clutch of the pushed type but it also finds application in the case of a clutch of the pulled type in which it is necessary to act in axial traction, that is to say that is to say from front to back, on the internal radial ends 18 of the fingers 20 of the diaphragm 12 to disengage (disengage) the clutch.
• FR-A-2 606477 see document FR-A-2 606477.
• the friction clutch 10 also includes a pressure plate 30 which is a massive annular part of revolution and which is delimited axially towards the front by a transverse friction face 32 which is intended to cooperate with a friction disc (not shown ), carrying at its outer periphery friction linings, which itself cooperates with the reaction plate (not shown).
• the reaction plate is intended to be locked in rotation on a driving shaft, such as the crankshaft of the internal combustion engine, while the friction disc is rotationally integral with a driven shaft (not shown) such as the input shaft of the vehicle transmission gearbox.
• the pressure plate 30 is integral in rotation with the cover 14 by means of elastic tongues of generally tangential orientation (not shown) which at the same time constitute elastic means for returning the pressure plate 30 in the direction of the cover 14, c that is to say that the pressure plate is permanently stressed axially from front to back (from left to right considering the figures) in the direction of the internal face 17 of the bottom 16 of the cover 14.
• the elastic axially acting engagement means constituted by the diaphragm 12 in a position independent of the wear of the linings of the friction disc, and to a lesser extent of the wear of the pressure plates 30 and reaction whose faces, called friction, also wear out in contact with the linings of the friction disc, there is a wear compensation device of generally known design of the ramp type.
• the wear take-up device 34 comprises ramp means, arranged circumferentially. More specifically, these ramp means comprise a ramp adjustment ring 36 which is a piece of cut and stamped sheet metal.
• the adjustment ring 36 generally comprises a radially inner part 38, of generally transverse orientation, which extends inward and which is interposed axially between the pressure plate 30 and the Belleville washer 24 of the diaphragm 12, and a radially outer part 40 of axial orientation.
• the radially inner part 38 of the ring 36 has ramps 44 arranged circumferentially and oriented axially forward towards the pressure plate 30, then the bearing zones 28 oriented axially backwards towards the washer Belleville 24 and the cover 14, these support zones 28 being for example constituted by the rounded rear edge of stamped arcs of a circle which are centered on the axis XX of the clutch and which are arranged radially to the outside with respect to the ramps 44. Thanks to the wear take-up device, the distance D between the friction face 32 of the pressure plate 30 and the bearing zones 28 of the ring 36 increases as the wear of friction linings.
• the pressure plate 30 has, on its rear transverse face 31, facing the internal face 17 of the bottom 16 of the cover 14, studs 46, which are here produced integrally by molding with the annular body of the pressure plate 30, which are distributed circumferentially at a distance from each other which corresponds to that which circumferentially separates two ramps 44 from the ring 36, each of the studs 46 being intended to cooperate individually with a ramp 44.
• the studs 46 belong to protrusions cooperating with the internal periphery of the part 40 for centering thereof.
• the ramp means 36, 44, 46 are arranged axially between the pressure plate 30 and the Belleville washer 24 of the diaphragm 12 so that the studs 46 cooperate with the ramps 44 while the diaphragm 12, 24 cooperates with the zones of support 28 which thus constitute the support means by means of which the diaphragm 12 acts on the pressure plate 30.
• the ramp means being metallic and obtained by stamping, the studs 46 being molded and machined, advantageously being chamfered to cooperate with the ramps 44.
• the ring 36 is rotated relative to the pressure plate 30 by means of a crown toothed device 48 which extends radially outwards the front axial end 50 of the radially outer part of axial orientation 40 of the ring 36.
• the crown 48 is intended to be rotated in the event of wear by the diaphragm via a control tab not shown.
• the adjusting ring 36 will rotate relative to the pressure plate 30, increasing the axial distance separating the bearing zones 28 from the rear friction face 32.
• This radially outer part 40 of the ring 36 extends axially from rear to front between the external peripheral zone 26 of the Belleville washer 24 of the diaphragm 12 and the pressure plate 30 and it comprises, in a known manner, a series of holes 52 for its lightening and for facilitating the circulation of air inside the mechanism for its cooling.
• the pressure plate 30 is permanently axially biased rearward towards the cover 14 by the tongues elastic (not shown) which link these two elements in rotation, and the bearing zones 28 of the adjustment ring 36 are kept permanently in contact with the portion facing the front transverse face 54 of the Belleville washer 24 by means of a series of elastic blades or hooks 56 which are angularly distributed regularly around the axis XX and one of which is illustrated in axial section in FIGS. 1 and 2.
• each elastic hook 56 has, in axial section, substantially the shape of a hairpin of generally transverse orientation which comprises a bend 58, produced in the form of a 180 ° fold, the convexity is oriented radially outwards and which connects two front 60 and rear 62 branches together.
• Each hook 56 is for example a piece of cut and folded sheet metal which is attached and fixed to the pressure plate 30. In the example illustrated in the figures, each hook 56 is arranged circumferentially in line with a ventilation hole 52 .
• the front branch 60 of each hook 56 has the function of ensuring the fixing of the hook 56 in a counterbore produced radially on the outside in the friction face 31 of the pressure plate 30.
• the fixing of the front branch 60 is here ensured by means of a rivet 84 which passes through a hole 86 formed in the thinned outer radial part of the pressure plate 30 and a corresponding hole formed in the front branch 60 for fixing the elastic hook 56 in the vicinity of the radially inner free end 68 of the latter.
• the various hooks 56 can for example be made in one piece in the general shape of a washer, the body in the general shape of transverse ring interconnects the parts which constitute the front branches 60 for fixing, such a washer can also be fixed to the pressure plate 30 by rivets or by any other means such as for example gluing or welding. It can be seen that, in the first embodiment illustrated in FIGS.
• the front branch 60 for fixing is generally shorter than the rear branch 62, the latter which extends radially inwards over a greater length having for the function of constituting an active elastic blade for direct or indirect return of the adjustment ring 36 in axial support towards the front, with its ramps 44 in axial support against the studs 46.
• the radially inner free end 64 of the rear branch 62 extends opposite the rear transverse face 66 of the outer radial periphery 26 of the Belleville washer 24.
• the free end 64 is shaped in a curved manner with its convexity oriented axially towards the front so as to be permanently resiliently pressed against the rear transverse face 66 of the Belleville washer 24.
• the point of application or contact of the free end 64 of the rear branch 62 is located radially substantially in line with the circumference along which extend the support zones 28 of the adjustment washer 36.
• the intermediate section 100 extends axially opposite the external peripheral edge of the external radial part 26 of the Belleville washer 24 as well as partially in front of the radially external part 40 of the adjustment ring 36.
• the ring 100 is arranged because for the high rotational speeds, it is centrifugal and is retained by the cover having an inclined portion opposite the section 100.
• one or more elastic hooks 56 makes it possible to guarantee that the ramps 44 remain in permanent contact with the studs 46 and this whatever the state of the clutch, it is ie it is in the engaged or disengaged position, and whatever the level of wear of the friction linings.
• the rear active branch or blade 62 of the elastic hook 56 acts directly on the adjustment ring 36 to press the latter axially forward towards the pressure plate 30 while that, in known manner, the latter is permanently axially stressed in the direction of the cover 14 by the rotational connecting tongues of these two elements.
• the design of the rear branch 62 is thus simpler insofar as it is generally rectilinear and of transverse orientation with its radially internal free end 64 which extends opposite a transverse annular face.
• rear 94 with which it cooperates permanently, the hook 56 being for this purpose mounted elastically prestressed.
• the rear annular face 94 is the rear face of the peripheral ring gear 48 which extends radially outwards the radially outer part 40, of axial orientation, of the adjustment ring 36.
• the free end 64 is here also shaped in a curved manner with its convexity oriented axially forward.
• the adjustment ring 36 is permanently axially tightened against the pressure plate 30 with the ramps 44 in contact with the studs 46.
• the outer periphery of the cover presented to the right of the central elbow 58 of the hook 56 has an annular rim of axial orientation preventing the hook 56 from centrifuging. Thanks to the invention, wear compensation is limited to what is necessary.

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

Applications Claiming Priority (3)

Publications (1)

Family

ID=9528835

Family Applications (1)

Country Status (4)

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Family Cites Families (7)

• 1998
  • 1998-07-21 FR FR9809285A patent/FR2782136B1/fr not_active Expired - Fee Related
• 1999
  • 1999-07-21 DE DE19981586T patent/DE19981586T1/de not_active Withdrawn
  • 1999-07-21 EP EP99932938A patent/EP1015784A1/de not_active Withdrawn
  • 1999-07-21 WO PCT/FR1999/001792 patent/WO2000005516A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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