WO2011135215A1

WO2011135215A1 - Double clutch in particular for a motor vehicle

Info

Publication number: WO2011135215A1
Application number: PCT/FR2011/050508
Authority: WO
Inventors: Christophe Mollier
Original assignee: Valeo Embrayages
Priority date: 2010-04-28
Filing date: 2011-03-14
Publication date: 2011-11-03
Also published as: DE112011101472B4; MX2012012553A; DE112011101472T5; FR2959542B1; FR2959542A1

Abstract

The present invention relates to a double clutch (10) comprising two clutch mechanisms (12, 14) which are capable of coupling an input shaft (16) to an internal output shaft (18) and an external output shaft (20), respectively, the internal output shaft (18) being mounted coaxially inside the external output shaft (20), in which each clutch mechanism (12, 14) comprises at least one diaphragm (30, 50) which is capable of being moved axially between an engaged clutch position and a disengaged clutch position, the double clutch (10) comprising actuation means (54, 56) which comprise at least one actuation abutment (58, 60) to move the diaphragm (30, 50) between said positions, and control means which are capable of controlling the axial movement of said abutment (58, 60), in which diaphragm the control means (54) of one (60) of the abutments comprise a control rod (62) which, held inside the internal output shaft (18) is capable of sliding axially to cause the movement of the abutment (60) between at least two positions corresponding to said engaged and disengaged clutch positions of the diaphragm (30), characterized in that said abutment (60) controlled by the control rod (62) is supported by the internal output shaft (18).

Description

The present invention relates to a double clutch, in particular for a motor vehicle.

The present invention relates more particularly to a double clutch, in particular for a motor vehicle, comprising two coaxial clutch mechanisms able to selectively couple an input shaft with an internal output shaft and an output output shaft, respectively. outlet being mounted coaxially inside the external output shaft, wherein each clutch mechanism comprises at least one friction disk interposed axially between a reaction plate and a pressure plate which is integral in rotation with the plate of reaction and mounted axially movable relative thereto, and which comprises a diaphragm adapted to be axially displaced between an engaged position and a disengaged position, the double clutch comprising actuating means which, associated with each clutch mechanism comprise at least one actuating stop for moving the diaphragm between said engaged positions and disengaged yée and control means of the stop capable of controlling the axial displacement of said stop.

Numerous double clutches of this type are known from the state of the art, for example from document FR 2 893 370.

Such a dual clutch has the recognized advantage of combining a reduction in vehicle consumption with the comfort of use obtained thanks to the fact that gear shifts are effected, without breaking the torque, by a controlled slip of two friction discs of the clutch, one being in the clutch phase while the other is in the disengagement phase.

In some cases, the control means of one of the abutments comprise a control rod which is housed inside the inner output shaft in the form of a hollow shaft, said control rod being adapted to slide axially to cause the displacement of the stop between at least two positions corresponding to said engaged and disengaged positions of the diaphragm.

In such an application, the two output shafts are therefore in the form of coaxial hollow shafts, the outer output shaft surrounding the inner output shaft itself traversed by the control rod.

The control rod is slidably mounted in an axial direction corresponding to the axis of rotation of the double clutch and carries the stop intended for the actuation of the diaphragm of one of the mechanisms of the double clutch, generally that of the clutch mechanisms arranged on the motor side.

In such an application, it is also known to take advantage of the use of a second hollow shaft as an internal output shaft containing the control rod for lubricating the rod in particular to increase the efficiency of the gearbox.

When such lubrication is used by means of a fluid such as oil, it is then necessary to ensure a seal between the control rod and the internal output shaft.

Generally, means for guiding the control rod relative to the shaft are also provided, such as a sliding bearing arranged radially between the control rod and the shaft.

However, the known solutions for such a particular application are not entirely satisfactory, in particular problems of reliability of the sealing means have been observed which lead to leakage of the lubricating fluid out of the cavity of the internal output shaft. .

In case of leaks, it will be understood that the lubricating fluid is then likely to spread in the mechanisms of the dry double clutch and to affect the proper functioning especially in the vicinity of the friction surfaces between the friction discs and trays pressure and reaction. The object of the present invention is to remedy in particular the aforementioned drawbacks of the solutions of the state of the art and to propose a simple, reliable and economical solution.

For this purpose, the invention proposes a double clutch of the type described above, characterized in that said stop controlled by the control rod is carried by the internal output shaft.

Indeed, the Applicant was able to identify that the sealing problems were due to strong stresses acting radially on the sealing means and that these stresses were attributable to coaxial defects between the double clutch on the one hand and the output shafts, the control rod bearing the stop on the other hand.

If in theory, the axis of displacement in the axial direction of the moving element, formed by the stop and the control rod which are connected together, must be the same as that of the clutch mechanism and particularly the diaphragm of the latter, it is clear that in reality it is not because of manufacturing tolerances.

Since the control rod is not centered relative to the associated clutch mechanism and to its diaphragm, the misalignment of the respective axes leads in operation to the occurrence of friction between the stop and the free end of the fingers of the clutch. diaphragm which cause stresses or efforts in the radial direction that are transmitted directly by the stop to the control rod carrying it.

However, it is these stresses or radial forces that are the cause of the deterioration of the sealing means causing the occurrence of the aforementioned leaks, the lubricating fluid contained in the inner output shaft being likely to escape and to spread in the clutch.

Such radial forces are also likely to deteriorate the guide means of the control rod of the stop. In addition, these problems are increased by the fact that, in a double clutch, the actuation time of the diaphragm of a clutch mechanism is of the order of 50% since there is always always the one of the clutch mechanisms that is open while the other closed, and vice versa, to allow the change of gear ratio without breaking in the transmission of the engine torque.

By comparison, it will be recalled that the stop of a simple clutch mechanism operates temporarily only to disengage when it is desired to change the gear ratio or start and stop the vehicle.

According to the invention, the principle therefore consists in decoupling the radial forces occurring due to the misalignment between the axes of axial orientation of the actuating rod and the diaphragm of the clutch mechanism.

Due to the fact that the stop is carried by the internal output shaft and no longer by the control rod as in the prior art, the radial forces resulting from the lack of coaxiality between the control rod of the stop and the diaphragm of the associated clutch mechanism are no longer transmitted by the stopper to said control rod.

Advantageously, the radial forces are integrally taken up by the internal output shaft carrying the stop, thus preserving the sealing means interposed between the inner output shaft and the control rod.

Thanks to the invention, the risks of leakage are eliminated and the reliability of the sealing means ensured.

Advantageously, the control rod is no longer subjected to radial forces, the sealing means as the guide means are at least likely to be smaller in size. Advantageously, the guide means could be removed to retain only sealing means in the applications involving the implementation of a lubricating fluid.

In the absence of such a lubricating fluid bearing means associated with the output shafts to the gearbox, the sealing means could also be removed.

According to other features of the invention:

at least the abutment is a self-centering abutment;

- The abutment comprises a sleeve having an inner cylindrical surface provided with axially oriented splines for cooperating with complementary splines of the inner output shaft;

the means for controlling the stop comprise an intermediate member which is capable of transmitting the axial displacement of the control rod to the actuating stop so that the stop is controlled in displacement between its two positions, corresponding to the engaged and disengaged from the diaphragm, when the control rod is itself moved axially relative to the internal output shaft carrying the stop;

said intermediate member is formed by a bearing comprising rolling means interposed between an outer ring which is connected in rotation to the control rod and an inner ring which is able to act on a sleeve of the abutment to cause axial displacement. between his two positions;

- The control means comprise means for adjusting the axial position of the intermediate member which is arranged between the control rod and the stop;

- The adjustment means are constituted by a screw-nut system comprising a threaded portion carried by the control rod and a nut for axially immobilizing a portion of the intermediate member;

- Guide means are interposed radially between the control rod and the inner output shaft; a lubricating fluid is introduced inside the internal output shaft and sealing means are interposed radially between the control rod and the internal output shaft;

the sealing means of the lubricating fluid consist of a dynamic seal, such as an annular lip seal.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the single figure which represents, in axial section, a half view of a double clutch according to a preferred embodiment of the invention.

By convention, the axial direction is defined by the X-X axis of rotation of the double clutch and the radial direction is orthogonal to said axis of rotation.

There is shown in Figure 1 a double clutch 10 for a motor vehicle according to a preferred embodiment of the invention, which is however given by way of non-limiting example.

The double clutch 10 comprises two clutch mechanisms, respectively a first clutch mechanism 12 and a second clutch mechanism 14.

The two clutch mechanisms 12, 14 are connected in parallel to ensure the coupling of an input shaft 16, forming a drive shaft connected to the motor, with two output shafts 18, 20 forming independent driven shafts. one of the other.

In a variant that is not shown, the two clutch mechanisms 12 and 14 are in series and the first clutch mechanism 12 makes it possible, in particular, to associate an input shaft with a rotating machine in an electric propulsion system and the second clutch mechanism 12. clutch 14 associates this rotating machine with a transmission system, for example the output shaft linked to a gearbox in the case of a motor vehicle.

The input shaft 16 is generally constituted by the crankshaft of an internal combustion engine fitted to the motor vehicle. The first output shaft 18, hereinafter internal shaft, and the second output shaft, hereinafter external shaft, are respectively formed as a hollow shaft delimiting an axially extending central cavity, the shaft internal output 18 being mounted coaxially inside the outer output shaft 20 which surrounds it over at least a portion of its length in the axial direction.

In the exemplary embodiment, the first clutch mechanism 12 is arranged on the engine side, on the right in the figure, and associated with the first internal output shaft 18, the first clutch mechanism 12 being intended to perform the functions Clutch and clutch clutch for odd gear ratios.

The second clutch mechanism 14 is arranged on the gearbox side, on the left in the figure, and associated with the second output external shaft 20, the second clutch mechanism 14 being intended to provide the clutch functions for the clutch. the even gear ratios and for reverse gear.

The first clutch mechanism 12 mainly comprises a friction disc 22 interposed axially between a reaction plate 24 and a pressure plate 26.

The friction disc 22 is rotatably connected to the internal output shaft 18 via an internally splined hub that it has at its inner radial periphery.

More specifically, the hub of the friction disk 22 comprises splines 23 of axial orientation which are intended to cooperate with complementary splines 25 of the internal output shaft 18 to ensure the transmission of the torque received from the d-shaft. entry 16.

The pressure plate 26 of the first clutch mechanism 12 is integral in rotation with the reaction plate 24 and is mounted axially movable relative thereto.

The first clutch mechanism 12 comprises a cover 28 on one side of which a diaphragm 30 is supported by means of known hinge means 32 which will therefore not be described in more detail.

The diaphragm 30 of the first clutch mechanism 12 is able to be moved axially between an engaged position and a disengaged position.

By convention, the engaged position of the diaphragm 30 corresponds to the position in which the first clutch mechanism 12 ensures the coupling of the input shaft 16 with the internal output shaft 18 and the disengaged position corresponds to the position wherein the first clutch mechanism 12 does not provide coupling of the input shaft 16 with the output external shaft 20.

Preferably, the first clutch mechanism 12 comprises a so-called automatic wear-compensating module, able to compensate for the wear of the friction linings 34 of the friction disc 22.

Advantageously, a damping flywheel 36 is interposed axially between the input shaft 16 connected to the engine and the first clutch mechanism 12.

Such a damping flywheel 36, shown only schematically in the figure, generally comprises a primary flywheel secured to the input shaft 16, a secondary flywheel equipped with a torque limiter and means for absorbing and damping the vibrations. and torque oscillations, such as springs arranged between the primary and secondary flywheels.

The secondary flywheel of the damping flywheel 36 is rotatably connected to the reaction plate 24 via the cover 28 of the first clutch mechanism 12, for example a connection 38 by meshing.

The second clutch mechanism 14 mainly comprises a friction disk 40 interposed axially between the reaction plate 24 and a pressure plate 42.

The friction disc 40 is rotatably connected to the outer output shaft 20 via an internally splined hub 44 and cooperates with complementary splines 46 of axial orientation of the external output shaft 20 to ensure the transmission of the torque received from the input shaft 16.

The pressure plate 42 of the second clutch mechanism 14 is rotationally integral with the reaction plate 24 and is mounted axially movable relative thereto.

The second clutch mechanism 14 comprises a cover 48 on one side of which a diaphragm 50 is supported by its outer radial portion forming a washer on hinge means 52, the inner radial portion of the washer of the diaphragm 50 cooperating with the plate pressure 42.

The diaphragm 50 of the second clutch mechanism 14 is adapted to be displaced axially between an engaged position and a disengaged position.

The double clutch 10 comprises actuating means, respectively first and second actuating means 54 and 56.

The second actuating means 56 comprise a stop 58 and control means in displacement of the stop 58 formed for example by an actuator, here hydraulic, able to selectively move a stop 58 in the axial direction to actuate the diaphragm 50 between the positions engaged and disengaged.

In a variant, the actuator associated with the stop 58 is of the electromechanical type.

The first actuating means 54, associated with the first mechanism 12 comprise an actuating stopper 60 for moving the diaphragm 30 between said engaged and disengaged positions.

The first actuating means 54 also comprise means for controlling the abutment 60 able to control the axial displacement of said abutment 60 associated with the diaphragm 30.

In the particular application of the double clutch 10 according to the invention, the control means of the stop 60 comprise a rod 62 which is housed inside the internal output shaft 18 in the form of a hollow shaft.

The control rod 62 is able to slide axially to cause displacement of the stopper 60 between at least two positions corresponding to said engaged and disengaged positions of the diaphragm 30.

According to the invention, the double clutch 10 is characterized in that said stop 60 controlled by the control rod 62 is carried by the internal output shaft 18.

Advantageously, the radial loads resulting from the coaxiality defects between the control rod 62 of the abutment 60 and the associated first clutch mechanism 12, more particularly its diaphragm 30, are only transmitted to said internal output shaft 18 and no longer to the control rod 62.

Preferably, the stop 60 is a self-centering stop.

Advantageously, the self-centering stop 60 is able to compensate for such coaxiality defects between the clutch mechanism 12 and the internal output shaft 18.

The self-centering stop 60 comprises at least one sleeve 64 and a bearing, said bearing comprising rolling means 66 interposed between an outer ring 68 intended to urge the fingers of the diaphragm 30 associated with the first clutch mechanism 12, and an inner ring 70 linked in rotation to said sleeve 64 by means of an elastic washer 72 for application.

Thanks to such an arrangement, the inner ring 70 is clamped between the spring washer 72 which urges it and a radial bearing face of the sleeve.

The self-centering abutment 60 thus allows a displacement in the radial direction between the sleeve 64 and the bearing capable of performing the self-centering function by compensating coaxiality defects between the internal output shaft 18 bearing the abutment 60 on the one hand and the diaphragm 30 of the clutch mechanism 12 on the other hand. Advantageously, the abutment 60 comprises a sleeve 64 comprising an internal cylindrical surface provided with splines 74 of axial orientation intended to cooperate with complementary splines 25 of the internal output shaft 18. As a variant, the internal cylindrical surface of the sleeve 64 is provided with a single drive means of the key or equivalent type.

By means of which the abutment 60 is, via its sleeve 64, rotatably connected by means of shapes to said internal output shaft 18, while remaining free to move axially in a determined stroke to actuate the diaphragm 30 between them. positions engaged and disengaged.

Advantageously, the control means of the abutment 60 comprise an intermediate member 76 which is capable of transmitting the axial displacement of the control rod 62 to the stop 60 of actuation.

Thus, the stop 60 is controlled in displacement between its two positions (corresponding to the engaged and disengaged positions of the diaphragm 30) when the control rod 62 is itself displaced axially with respect to the internal output shaft 18 carrying the stop 60 .

Preferably, said intermediate member 76 is formed by a bearing, such as a ball bearing, comprising rolling means 78 interposed between an outer ring 80 which is rotatably connected to the control rod 62 and an inner ring 82 which is able to act on a sleeve 64 of the stop 60 to cause the axial displacement between its two positions.

The inner ring 82 cooperates with an adjacent radial face 84 of the sleeve 64 of the abutment 60.

In a variant not shown, the structure of the ball bearing is reversed. An outer ring is connected in rotation to the control rod 62 and an inner ring is able to act on a sleeve 64 of the abutment 60 to cause axial displacement between its two positions. The inner ring cooperates with an adjacent radial face 84 of the sleeve 64 of the abutment 60.

Advantageously, the control means formed by the rod 62 comprise means 86 for adjusting the axial position of the intermediate member 76 constituted by the bearing which is arranged between the control rod 62 and the abutment 60 of the first clutch mechanism. 12.

Advantageously, the adjustment means 86 are constituted by a screw-nut system comprising a threaded portion 88 carried by the control rod 62 and a nut 90 intended to immobilize axially a portion of the intermediate member 76, such as the outer ring 80 of the bearing forming said member 76.

In the preferred embodiment of the invention, guiding means 92 are interposed radially between the control rod 62 and the internal output shaft 18.

Advantageously, the guiding means 92 are constituted by a smooth bearing.

Preferably, a lubricating fluid is introduced inside the internal output shaft 18 so that sealing means 94 are interposed radially between the control rod 62 and the internal output shaft 18.

Advantageously, the lubricating fluid can thus spread out of the cavity of the internal output shaft 18, to the clutch mechanisms 12 and 14.

Preferably, the sealing means 94 of the lubricating fluid consist of a dynamic seal, such as an annular lip seal.

Claims

1. Double clutch (10), in particular for a motor vehicle, comprising two coaxial clutch mechanisms (12, 14) capable of selectively coupling an input shaft (16) with respectively an internal output shaft (18) and an external shaft of outlet (20), the inner output shaft (18) being coaxially mounted within the outer output shaft (20), wherein each clutch mechanism (12, 14) has at least one friction (22, 40) interposed axially between a reaction plate (24) and a pressure plate (26, 42) which is rotationally integral with the reaction plate (24) and axially movable relative thereto, and which comprises a diaphragm (30, 50) adapted to be displaced axially between an engaged position and a disengaged position, the double clutch (10) comprising actuating means (54, 56) which, associated with each clutch mechanism ( 12, 14), comprise at least one stop (58, 60) for actuating to move r the diaphragm (30, 50) between said engaged and disengaged positions and stop control means (58, 60) adapted to control the axial displacement of said stop (58, 60), wherein the control means (54, 60) ) of one (60) of the stops comprises a control rod (62) which is housed inside the internal output shaft (18) in the form of a hollow shaft, said control rod ( 62) being axially slidable to cause displacement of the stop (60) between at least two positions corresponding to said engaged and disengaged positions of the diaphragm (30),

characterized in that said stop (60) controlled by the control rod (62) is carried by the internal output shaft (18).

2. Double clutch (10) according to claim 1, characterized in that at least the stop (60) is a self-centering stop.

3. Double clutch (10) according to one of claims 1 or 2, characterized in that the stop (60) comprises a sleeve (64) having an inner cylindrical surface provided with grooves (74). axial orientation for cooperating with splines (25) complementary to the inner output shaft (18).

4. Double clutch (10) according to claim 1, characterized in that the control means of the stop (60) comprise an intermediate member (76) which is capable of transmitting the axial displacement of the control rod (62) to the stop (60) of actuation so that the stop (60) is controlled in displacement between its two positions, corresponding to the engaged and disengaged positions of the diaphragm, when the control rod (62) is itself displaced axially relative to the internal output shaft (18) bearing the stop (60).

5. Double clutch (10) according to claim 4, characterized in that said intermediate member (76) is formed by a bearing comprising rolling means (78) interposed between an outer ring (80) which is rotatably connected to the control rod (62) and an inner ring (82) which is able to act on a sleeve (64) of the stop (60) to cause axial displacement between its two positions.

6. Double clutch (10) according to one of claims 4 or 5, characterized in that the control means (62) comprise means (86) for adjusting the axial position of the intermediate member (76) which is arranged between the control rod (62) and the stop (60).

7. Double clutch (10) according to claim 6, characterized in that the adjusting means (86) are constituted by a screw-nut system comprising a threaded portion (88) carried by the control rod (62) and a nut (90) for axially immobilizing a portion (80) of the intermediate member (76).

8. Double clutch (10) according to any one of claims 1 to 7, characterized in that guide means (92) are interposed radially between the control rod (62) and the internal output shaft (18) .

Double clutch (10) according to one of Claims 1 to 8, characterized in that a lubricating fluid is introduced into the internal output shaft (18) and that sealing means (94) are radially interposed between the control rod (62) and the internal output shaft (18).

10. Double clutch (10) according to claim 9, characterized in that the sealing means (94) of the lubricating fluid are constituted by a dynamic seal, such as an annular lip seal.