WO2015092198A2

WO2015092198A2 - Friction clutch system

Info

Publication number: WO2015092198A2
Application number: PCT/FR2014/053166
Authority: WO
Inventors: Hervé MAUREL; Roel Verhoog
Original assignee: Valeo Embrayages
Priority date: 2013-12-16
Filing date: 2014-12-04
Publication date: 2015-06-25
Also published as: FR3014977A1; WO2015092198A3; CN105793595A

Abstract

The invention relates to a friction clutch system (10) which comprises a drive plate (16) rotating about an axis of rotation (100) of the clutch system and intended for being rotatably secured to a crankshaft (12), a non-deformable pressure plate (18) rotating about the axis of rotation (100) and translatably movable parallel to the axis of rotation (100) between an engaged position and a disengaged position, and at least one friction disc (20) arranged between the engine plate (16) and the pressure plate (18), in contact with the engine plate (16) and the pressure plate (18) in the engaged position. An actuator (34) translates the pressure plate from the disengaged position to the engaged position. A rotary abutment (42) is inserted between the actuator (34) and the pressure plate (18). The rotary abutment (42) is translatably stationary relative to the pressure plate (18) and relative to the actuator (34). By ensuring that the pressure plate does not deform axially during the engagement and disengagement movements, and forms an integral movable device with the rotary abutment and the actuator, which moves as a unit, the movements and the forces of the actuator of the pressure plate are integrally transmitted, with very short travel, high-energy efficiency and low hysteresis.

Description

FRICTION CLUTCH SYSTEM

TECHNICAL FIELD OF THE INVENTION

The invention relates to a friction clutch system, in particular for a drive kinematic chain of a vehicle, and in particular for automated clutch functions.

STATE OF THE PRIOR ART

Dry diaphragm clutch actuators are generally controlled in racing, given the flexibility of their components and the hysteresis in force introduced by the friction joints of the diaphragms or levers. The actuators associated with these clutches generally include passive assistance devices and lengthening to bear the low efficiency and dispersions and dimensional variations of these clutches. These mechanisms complicate and increase the actuators. In addition, the actuating strokes being important because of the gear ratios, they penalize the size of the clutch and the actuator.

In US 8,096,395 is described a normally open clutch system, having a friction disc clamped between a pressure plate and a motor plate connected to a crankshaft. The pressure plate is actuated by a piston of a hydraulic actuator. The hydraulic actuator is fixed in rotation, and the movements of the piston are transmitted to the pressure plate by means of a rolling stop. To return the pressure plate and the piston to a disengaged position, an elastic member is interposed between the pressure plate and the friction disk. This construction imposes an important stroke for the piston, which must, during the clutch, compress the intermediate elastic element.

SUMMARY OF THE INVENTION

The invention aims to overcome the disadvantages of the state of the art and to provide a simple clutch system ensuring high efficiency, low hysteresis and low actuation stroke. To do this is proposed, according to a first aspect of the invention, a friction clutch system comprising: a motor plate rotating about an axis of rotation of the clutch system and intended to be secured in rotation a crankshaft, - a non-deformable pressure plate rotating about the axis of rotation and movable in translation parallel to the axis of rotation between an engaged position and a disengaged position, at least one friction disk disposed between the motor plate and the pressure plate, in contact with the motor plate and the pressure plate in the engaged position, an actuator fixed in rotation and movable in translation to translate the pressure plate in translation from the disengaged position to the engaged position, and a rotary stop interposed between the actuator and the pressure plate, fixed in translation relative to the pressure plate and with respect to the actuator.

By ensuring that the pressure plate does not deform axially during clutch movement and disengagement, and forms with the rotary stop and the actuator a movable mobile unit moving a block, it ensures an integral transmission of the movements and forces of the actuator to the pressure plate, with a very short stroke, a high energy efficiency and a low hysteresis. Preferably, the rotary stop is rolling.

[0007] Preferably, the motor plate and the pressure plate are connected in rotation. Furthermore, one or more elastic return elements of the pressure plate to the disengaged position, located for example radially outside the friction disc, can be provided between the motor plate and the pressure plate. This produces a normally open clutch system. According to a particularly advantageous embodiment, the system comprises tabs elastically rotating links between the motor plate and the pressure plate, reminding the pressure plate to the disengaged position. The resilient tongues, in the form of leaf springs, are preferably fixed at one end to the pressure plate and at another end to the motor plate. The clutch system according to the invention is particularly suitable for an automated clutch. The actuator preferably comprises a hydraulic receiver connected to a hydraulic generator by a hydraulic circuit. According to a particularly advantageous embodiment, the hydraulic circuit comprises a pressure regulator between the hydraulic generator and the hydraulic receiver. It is then possible to provide a control module for assigning a pressure setpoint to the pressure regulator according to a clutch control signal. It is therefore advantageous for the hydraulic circuit to include a pressure sensor in the hydraulic circuit, which makes it possible to regulate the pressure of the actuator. In other words, it replaces the sophisticated control in displacement used in the usual way with the diaphragm clutch actuators by pressure control, so force, much simpler. The hydraulic generator may be a hydraulic pump, preferably a volumetric or centrifugal hydraulic pump.

According to one embodiment, the system comprises an elastically deformable connection interface between the motor plate and a crankshaft, which allows a decoupling in axial translation and / or bending between the crankshaft and the clutch system. This connection can in particular be achieved by a flexible sheet star, having a central hub fixed to the crankshaft and branches fixed to the motor plate. Preferably, the clutch system comprises a thrust bearing axial force recovery interposed directly or indirectly between the motor plate and a housing element. The thrust bearing may, if necessary, be arranged in the crankcase, between the crankcase and the crankshaft, in the event that the crankshaft is rigidly connected in translation to the engine plate. Alternatively, the thrust bearing can be mounted on the motor plate, between the latter and a housing element separating the motor from the clutch system, for example on a wall exterior of a crankcase or an inner wall of a clutch housing. Preferably, the thrust bearing is located inside the clutch housing, which contains the motor plate, the friction disk, the pressure plate, and preferably the actuator. In the presence of a flexible sheet for the elastic connection interface between the crankshaft and the motor plate, it can be provided that the branches of the star sheet pass through openings in the motor plate. Alternatively, an indeformable piece intermediate between the motor plate and the thrust bearing may be provided, which may be mounted on the motor plate together with the elastic connection interface. Advantageously, the non-deformable support piece of the thrust bearing is fixed to the motor plate by screws also serving for fixing the elastic connection interface. These arrangements offer an advantage of compactness and simplicity compared to a solution, also conceivable, of a housing element located axially between the connecting web and the motor plate. The thrust bearing can be of any suitable type, including smooth contact or rolling, and preferably comprises a bearing, preferably ball, axial or oblique contact. It can also be a roller bearing or needle.

According to one embodiment, the thrust bearing is in plane contact with the housing element, in a plane perpendicular to the axis of rotation. The rotating thrust bearing then contributes to the stiffening of the rotating assembly and the decoupling between the crankshaft and the engine plate.

Alternatively, the thrust bearing may be in linear contact with the housing element and be able to pivot about a pivot axis perpendicular to the axis of rotation, secant with the axis of rotation. Voluntarily leaving the motor plate a degree of freedom of pivoting to possibly accompany the bending of the crankshaft during the phases of explosions of the engine cylinders. This solution will be particularly interesting when all cylinders have the same orientation (in-line cylinders) or orientations close, perpendicular or substantially perpendicular to the pivot axis.

To provide not one, but two degrees of freedom of pivoting the motor plate, the thrust bearing can also be constituted by a spherical bearing.

The friction disk is preferably connected to a hub for fixing a gearbox input shaft, optionally with the interposition of a torsion damper.

The pressure plate preferably has friction surfaces in contact with the friction disc and preferably located radially outside the rotary stop. Similarly, the motor plate preferably has friction surfaces in contact with the friction disc and preferably located radially outwardly of the thrust bearing.

According to another aspect of the invention, it relates to an assembly comprising an internal combustion engine, and a clutch system as described above, the engine plate is fixed to the crankshaft of the engine.

According to another aspect of the invention, it relates to an assembly comprising an internal combustion engine with cylinders in line parallel to a reference axis perpendicular to the axis of rotation, and a clutch system. as described above, of the type comprising a thrust bearing bearing axial forces, interposed directly or indirectly between the motor plate and a housing element, in linear contact with the housing element so as to be able to rotate around a pivot axis perpendicular to the axis of rotation, secant with the axis of rotation, the pivot axis at an angle of 90 °, or between 80 ° and 100 ° with the axes of the cylinders.

The invention also relates to a friction clutch system comprising: a motor plate rotating about an axis of rotation of the clutch system and intended to be secured in rotation to a crankshaft, a non-deformable pressure plate rotating about the axis of rotation and movable in translation parallel to the axis rotation between an engaged position and a disengaged position,

elastic tongues for connecting in rotation between the motor plate and the pressure plate, reminding the pressure plate towards the disengaged position,

at least one friction disk disposed between the motor plate and the pressure plate, in contact with the motor plate and the pressure plate in the engaged position, said friction disk being connected to a hub for fixing a shaft of gearbox input with the interposition of a torsion damper,

an actuator fixed in rotation and movable in translation to translate the pressure plate in translation from the disengaged position to the engaged position,

a rotary stop interposed between the actuator and the pressure plate, fixed in translation relative to the pressure plate and relative to the actuator.

BRIEF DESCRIPTION OF THE FIGURES

Other features and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures, which illustrate: FIG. 1, a section of a clutch system according to a first embodiment of FIG. embodiment of the invention; Figure 2, a section of a clutch system according to a second embodiment of the invention; Figure 3, a section of a clutch system according to a third embodiment of the invention; Figure 4 is a side view of a clutch system according to a fourth embodiment of the invention; FIG. 5, a detail of a crankcase element of the clutch system of FIG. 4. For the sake of clarity, identical or similar elements are marked by identical reference signs throughout the figures.

DETAILED DESCRIPTION OF EMBODIMENTS

In Figure 1 is illustrated a dry clutch system 10, which allows to establish and release a coupling between a motor shaft, here the end of a crankshaft 12, and a receiving element, here a tree not shown flute fitting into a splined hub 14 of the clutch system 10. The clutch system 10 comprises a motor plate 16 constituting a flywheel integral with the crankshaft 12 and rotating about an axis of rotation 100 of the system a non-deformable pressure plate 18 rotating about the axis of rotation 100, and a friction disk 20 disposed between the motor plate 16 and the pressure plate 18, and equipped with friction linings 22.

In this embodiment, the friction disc 20 is connected to the splined hub 14 via a torsion damper 24, although this stage can be omitted. By way of purely illustrative and non-limiting example, FIG. 1 shows a torsion damper 24 comprising a web 26 fixed to the splined hub and situated axially between two guide washers 28, the friction disk 20 being fastened to one of the two washers. In a known manner, springs 30 are arranged between the guide washers 28 and the web 26, so as to allow a small amplitude elastic angular deflection between the washers and the web around the axis of rotation 100.

The pressure plate 18 is movable in translation relative to the motor plate 16 parallel to the axis of rotation 100 between a disengaged position without contact with the friction linings 22 and an engaged position, wherein at least some of the linings 22 of the friction disc 20 are in contact with the motor plate 16 and at least some of the friction linings 22 of the friction disc 20 are in contact with the pressure plate 18.

Spring blades 32 are fixed at one end to the pressure plate 18 and at another end (not visible in Figure 1) to the motor plate 16, so as to substantially secure the pressure plate 18 and the motor plate 16 in rotation and resiliently return the pressure plate 18 to the disengaged position, in a direction opposite to the motor plate 16, to the right in Figure 1.

The pressure plate 18 is driven in translation from the disengaged position to the engaged position, to the left in Figure 1, by a hydraulic actuator 34. This actuator 34 comprises a body 36 defining an annular pressure chamber 38 and an annular piston 40 sliding axially in this chamber 38. A rotating thrust bearing 42 is interposed between the actuator 34 and the pressure plate 18, to transmit the translation movements of the piston 40 to the pressure plate 18, but to prevent the pressure plate 18 rotates the piston 40. Remarkably, the rotary stop 42 forms on one side with the piston and on the other with the pressure plate a movable element in translation of a block, without deformation, so that is assured an integral transmission of the movement of the piston to the pressure plate and singularly to the surfaces of the plate 18.1 pressure coming into contact with the toppings ion. The motor plate 16 is preferably itself undeformable, which contributes to a high reactivity of the control due to the small strokes between the disengaged position and engaged. In this embodiment, provision is made, for the recovery of the axial clutch forces exerted by the actuator 34, a thrust bearing 44 located in the crankcase, between an element 46 of the crankcase and the crankshaft 12, and constituted by a ball or roller bearing with angular or axial contact or a needle bearing or a plain bearing.

The motor plate 16, the pressure plate 18 and the friction disk 20, and the actuator 34 are disposed inside a housing 48 consisting of a body 50 closed by a cover 52 which can or not be common with a motor housing, and having a hole 52.1 passage of the end of the crankshaft 12. It is it should also be noted that, in the absence of an axial thrust bearing abutment bearing inside the crankcase, the sliding bearing provided at the bore 52.1 may also constitute a thrust bearing 144.

The actuator is powered by a hydraulic circuit 54 comprising a pump 56, for example a positive displacement pump or a centrifugal pump, delivering hydraulic fluid under pressure from a reservoir 58. The pump 56 is driven for example by an electric motor 60, itself controlled by a control circuit 62. A pressure sensor 64 is inserted into the hydraulic circuit 54 and sends a signal to the control circuit 62. A calibrated pressure drop 66 can be inserted into the circuit , or integrated with the pump 56. The pump 56 and the electric motor 60 can be arranged indifferently inside the casing 48, on an outer wall of the casing 48 or elsewhere in the vehicle.

The clutch system 10 operates in the following manner. The system is said to be normally open, in the sense that, in the absence of pressure in the feed hydraulic circuit 54, the spring blades 32 return the pressure plate 18 to the disengaged position, the friction disk 20 then being decoupled. crankshaft 12.

In response to a clutch order, received for example from an automation controlling the gear changes in a gearbox located downstream of the clutch system 10, the control circuit 62 causes the engine power supply. 60 which drives the pump 56. The work to provide to bring the system into the engaged position is low, and corresponds to the deformation of the leaf spring 32. By driving the electric motor 60 so that the pressure supplied by the pump 56 and measured by the sensor 64 corresponds to a desired clutch curve, it perfectly controls the transient phase clutch. It is also possible to provide different pressure setpoint curves as a function of time, corresponding to different clutch modes, according to the order received by the control circuit. Once the coupling between the motor plate 16 and the hub 14, thus between the crankshaft 12 and the input shaft of the gearbox, has been achieved, a coupling pressure is maintained at the level of the actuator 34. 'no declutching order is received. Upon receipt of a disengagement order, the motor 60 decreases or stops, so that the springs 32 recall the pressure plate 18, the rotary stop 42 and the piston 40 of the actuator 34 to the disengaged position, with a dynamic function of the calibrated pressure drop 66 introduced in the hydraulic circuit 54. It is also conceivable to assist the action of the springs by turning the pump in the opposite direction if a rapid disengagement is desired.

The clutch system 10 thus defined is particularly suitable for a vehicle having a running control function in the disengaged mode, which optimizes the running time without coupling the engine, for example by monitoring the torque and imposing a disengagement as soon as the engine is likely to behave like a brake.

In Figure 2 is illustrated a clutch system according to a second embodiment of the invention, which differs from the previous essentially by the guide mode of the motor plate 16 and its coupling to the crankshaft 12. In this mode in fact, the thrust bearing bearing 44 is integrated in the casing 48 of the clutch system 10, directly between the motor plate 16 and the cover 52 of the casing, and is in the form of a bearing ball bearing with axial load, having a first bearing ring 44.1 in direct plane bearing against an inner face of the cover 52 of the casing, a second bearing ring 44.2 in direct plane bearing against the motor plate 16. By plane bearing means here a support in three non-aligned points at least, prohibiting any pivoting. In practice, one of the rings 44.1, 44.2 is preferably hooped on the cover 2 of the housing or the motor plate 16, the other ring being in simple axial support, with the possibility of positioning radially free. The motor plate 16 is connected to the crankshaft 12 via a flexible sheet star 70 passing through openings in the motor plate 16 and fixed to the motor plate 16 and the crankshaft 12 by screws 72 , 74. This flexible sheet 70 carries an elastic connection interface giving the crankshaft 12 freedom of movement in flexion and in translation relative to the motor plate 16. The other components of the clutch system 10 are identical to those of the previous embodiment, which will be referred to for their detailed description. As illustrated, the thrust bearing 44 is located radially inside the friction linings 22, thus radially inside the corresponding annular contact face 16.1 of the motor plate 16. Similarly, the rotary stop 42 is located radially inside the friction linings 22, thus radially inside the corresponding contact face 18.1 of the pressure plate 18.

During the clutching and holding phases in the engaged position, the forces exerted by the actuator in the axial direction (to the left in the figure) are taken up by the thrust bearing 44. All the mechanical functions of the system clutch are then united in the housing of the clutch 48.

In Figure 3 is illustrated a variant of the clutch system of Figure 2. To simplify the geometry and the embodiment of the motor plate 16 and thermally isolate the motor plate 16 of the thrust bearing 44, there is provided a part 76 deformable 44.2 support of the rings of the thrust bearing 44, which is fixed to the motor plate 16 by screws 72 also for fixing the star sheet 70 forming the elastically deformable interface between the crankshaft 12 and the plate 16. The other composting clutch system are identical to the previous embodiments.

In Figure 4 has been illustrated another variant of the clutch system of Figure 2, in a side view without the housing. In this view, there is a plate 80 intended to be attached to or part of the crankcase, on which is formed or attached a cylindrical bearing surface 82 for abutment bearing 44. This plate 80 has been illustrated. only in FIG. 5, to better visualize the cylindrical bearing surface 82 which extends along a diameter of a hole 84 through which the end of the crankshaft passes. The thrust bearing 44, bearing against this cylindrical surface 82 along a nip, can pivot about a pivot axis perpendicular to the axis of rotation 100 and secant (at least in a central position) with the axis The other components of the clutch system are identical to those of the previous embodiments. We understands that in this configuration, the motor plate 16 can follow the bending of the crankshaft 12 induced by the explosions in the cylinders of the engine. This arrangement is particularly useful for an inline engine, inducing a first mode of bending deformation of the crankshaft with a fixed bending axis, despite the rotation of the crankshaft.

In another variant not shown, there may be a thrust bearing 44 consisting of a spherical bearing.

Naturally, the examples shown in the figures and discussed above are given for illustrative and not limiting. It is explicitly provided that the various illustrated embodiments can be combined with one another to propose others.

The clutch system may comprise more than one friction disk 20, more than one pressure plate 18 and more than one motor plate 16.

The hydraulic circuit can be of any type adapted to the control of the actuator 34. If there is also a constant pressure hydraulic circuit in the vehicle, one can control the supply of the chamber 36 of the actuator 34 with valves opening or closing the supply of the chamber 36. A valve may also be provided to isolate the chamber 36 to limit consumption in the hydraulic circuit. To limit power consumption, a non-return valve can be placed just downstream of the pump 56 and the fixed restriction 66 can be replaced by a controlled flow solenoid valve.

The motor plate 16 can be sized to be the only flywheel, or can be lightened if another flywheel exists upstream of the clutch system.

Claims

Friction clutch system (10) comprising:

a motor plate (16) rotating about an axis of rotation (100) of the clutch system and intended to be secured in rotation to a crankshaft (12),

a non-deformable pressure plate (18) rotating about the axis of rotation (100) and movable in translation parallel to the axis of rotation (100) between an engaged position and a disengaged position, resilient tongues (32) of connection in rotation between the motor plate (16) and the pressure plate (18), reminding the pressure plate (18) towards the disengaged position,

at least one friction disk (20) disposed between the motor plate (16) and the pressure plate (18), in contact with the motor plate (16) and the pressure plate (18) in the engaged position, said disk friction device being connected to a fixing hub (14) of a gearbox input shaft with the interposition of a torsion damper,

an actuator (34) fixed in rotation and movable in translation to translate the pressure plate in translation from the disengaged position to the engaged position,

a rotary stop (42) interposed between the actuator (34) and the pressure plate (18),

characterized in that the rotary stop (42) is fixed in translation relative to the pressure plate (18) and with respect to the actuator (34).

Friction clutch system according to one of the preceding claims, characterized in that the actuator (34) comprises a hydraulic receiver (34) connected to a hydraulic generator (56) by a hydraulic circuit (54).

Friction clutch system according to claim 2, characterized in that the hydraulic circuit (54) has a control (62) for regulating the pressure in the hydraulic circuit (54) according to a clutch control signal.

Friction clutch system according to any one of claims 2 to 3, characterized in that it comprises a pressure sensor (64) in the hydraulic circuit (56).

Friction clutch system according to any one of the preceding claims, characterized in that it comprises a connection interface (70) elastically deformable between the motor plate (16) and the crankshaft (12).

Friction clutch system according to any one of the preceding claims, characterized in that the clutch system (12) comprises a thrust bearing (44) axial force recovery interposed directly or indirectly between the motor plate (16) and a housing member (46, 52).

Friction clutch system according to the combination of claims 5 and 6, characterized in that it comprises a non-deformable piece (76) for supporting the thrust bearing (44) fixed to the motor plate (16) by screws (72) also for fixing the elastic connection interface (70).

Friction clutch system according to Claim 6, characterized in that the thrust bearing (44) is located inside a clutch housing (48) containing the driving plate (16), the friction disc (20), the pressure plate (18), and preferably the actuator (34).

Friction clutch system according to claim 6, characterized in that the thrust bearing (44) is mounted on the crankshaft (12).

Friction clutch system according to one of Claims 6 to 9, characterized in that the thrust bearing (44) has an axial or angular contact ball bearing.

1 1. Clutch system according to one of Claims 6 to 10, characterized in that the thrust bearing (44) is in plane contact with the housing element (46, 52).

12. Clutch system according to any one of claims 6 to 10, characterized in that the thrust bearing (44) is in linear contact with the housing element (80) and is pivotable about a pivot axis perpendicular to the axis of rotation (100), intersecting with the axis of rotation.

A friction clutch system according to any one of the preceding claims, characterized in that the pressure plate (18) has friction surfaces (18.1) in contact with friction disk lining (22) (20). ) in the engaged position and located radially outside the rotary stop (42).

14. An assembly comprising an internal combustion engine having a crankshaft (12) and a clutch system (10), characterized in that the clutch system is according to any one of the preceding claims, the engine plate (16) of the clutch system being attached to the crankshaft (12).

15. An assembly comprising an internal combustion engine with cylinders in line parallel to a reference axis, characterized in that it further comprises and a clutch system according to claim 12, the pivot axis making an angle of 90 ° with the reference axis.