WO2007074259A2

WO2007074259A2 - Multi-disc clutch for a gear box of a motor vehicle and associated gear box

Info

Publication number: WO2007074259A2
Application number: PCT/FR2006/051324
Authority: WO
Inventors: Michel Raoul; Philippe Rodrigues
Original assignee: Renault S.A.S.
Priority date: 2005-12-22
Filing date: 2006-12-11
Publication date: 2007-07-05
Also published as: WO2007074259A3; FR2895475A1

Abstract

The multi-disc clutch for the gear box of a motor vehicle comprises an input element (9), at least one first disc (20) supported by said input element, an output bell (10), at least one second disc (31), a mechanical control member (11) which is used for clamping the discs and is substantially coaxial with respect to said output bell. The clutch also comprises means (40, 41) which are used for amplifying the clamping force applied on the discs mounted on the output bell and controll member and enable said controll member and output bell to be linearly remote from each other along said axis during the torque transmission.

Description

Multidisk clutch for a motor vehicle gearbox, and associated gearbox.

The present invention relates to the field of internal control devices for gearboxes for a motor vehicle.

The present invention more particularly relates to a multi-plate clutch for a parallel shaft gearbox, comprising first and second sets of discs able to come into friction contact with each other so as to ensure the transmission of a motor torque to a primary shaft of the gearbox. Such a position is generally called "engaged position".

The transition from the engaged position to a disengaged position, called the "disengaging phase", is controlled by the movement of a clutch control stop between a rest position and an active position. By returning to its rest position, the control stop allows the passage of the disengaged position to the engaged position, called "clutch phase". This clutch phase is used when shifting the gearbox to balance the rotational speeds of the crankshaft of the engine and the primary shaft of the gearbox. This clutch phase is also used when starting the vehicle, for its setting in motion from a stop position. For more details on the passage of gear ratios of a gearbox, one can for example refer to the documents FR-A-2 643 428 and FR-A-2 699 632.

In order to obtain a sufficient clamping pressure on the disks of the clutch, a hydraulic device is generally provided for controlling the displacement of the control stop. However, the use of such a member requires the provision of supply lines, a hydraulic fluid distributor, as well as control and compensation chambers. The implementation of these elements inside the gearbox housing can be relatively difficult and substantially increases the total volume of the transmission.

The present invention therefore aims to overcome these disadvantages by providing a multi-plate gearbox clutch for obtaining a satisfactory clamping pressure on the discs without using a hydraulic control member.

For this purpose, the multidisc clutch for a motor vehicle gearbox is provided with an input element, at least a first disk, an output bell, at least a second disk, a mechanical control member for clamping the discs substantially coaxial with the exit bell.

The clutch also comprises means for amplifying the clamping force applied to the discs mounted on the outlet bell and on the control member, said means being able to allow a relative linear distance from the control member. and the output bell along said axis, when transmitting a torque.

With such a clutch, it becomes possible to obtain a sufficient clamping pressure on the clutch discs, using only mechanical control members. Indeed, the existence of such means between the output bell and the control member makes it possible to obtain, during the transmission of the torque, a relative distance of these two elements, which increases the pressure applied to the disks. In a preferred embodiment, the amplification means mounted on the control member comprises an inclined ramp adapted to cooperate with a complementary ramp of the amplification means mounted on the output bell. The use of such ramps thus makes it possible, when transmitting torque from the input shaft to the output shaft, to amplify the clamping force applied to the discs in a relatively simple and economical manner. .

Advantageously, the clutch comprises elastic members mounted between the outlet bell and the control member.

The control member may be configured to maintain, in a rest position, the clamping of the discs under the effect of the elastic members.

Preferably, the clutch comprises guides for the elastic members and centering pins of said guides.

Preferably, the input element comprises an inlet bell centered on the output shaft which is the primary shaft of the gearbox.

In one embodiment, the control member slides along said axis on the exit bell. The control member may advantageously comprise a thrust bearing for controlling the clutch and disengagement maneuvers.

Preferably, the controller comprises the second series of disks. The clutch may be provided with a single adjusting washer mounted between the inlet bell and a clutch housing.

The present invention also relates to a gearbox for a motor vehicle comprising a clutch as defined above. The present invention will be better understood in the study of a detailed embodiment described by way of nonlimiting example, and illustrated by the appended drawings, in which:

FIG 1 shows a partial sectional view of a motor vehicle gearbox showing the mounting of a clutch according to the invention disposed at the entrance of said box; and

FIG 2 is a sectional view along the axis II-II of Figure 1.

The gearbox, referenced 1 as a whole, comprises a clutch housing 2 inside which is mounted a multi-disc clutch 3 disposed on a primary shaft 4 of the box.

The primary shaft 4, extending substantially along its axis 5, is mounted at one end of the clutch housing 2 via a bearing 6, which can be for example a ball bearing. Inside the clutch housing 2, intermediate shafts 7 and 8 of the gearbox are also mounted here.

The clutch 3 is provided with an inlet bell 9, an outlet bell 10, and a control member 11.

The inlet bell 9 comprises a stepped axial tubular portion 12 mounted in part on the primary shaft 4, via a ring 13 attached to an axial end of said shaft. A part

12a of the tubular portion 12 is axially projecting from said end of the shaft 4. The portion 12a is splined so as to receive a driving torque via a damping flywheel (not shown). The inlet bell 9 thus forms the input element of the clutch 3.

In order to seal the clutch housing 2, the portion 12a comprises, at its free axial end, a plug 14. For this purpose, it is also provided between a closing cap 2a of the housing 2 clutch and the tubular portion 12, a dynamic seal.

The portion 12a of tubular portion 12 is extended, axially on the side opposite the stopper 14, by a first radial portion 16 extending inside the casing 2 in the vicinity of the cover 2a, which is itself extended by a second portion radial 17. The second radial portion 17 is here attached to the first portion 16 by welding. Of course, it is also conceivable to use other fastening means such as screws, or to make the bell 9 in one piece, by stamping and folding a blank sheet of steel.

The second radial portion 17 is extended, from a free edge of large diameter, by an axial portion 18 extending on the opposite side to the cover 2a. On its outside, the axial portion 18 supports a mass of inertia 19 sized to increase the overall inertia of the clutch 3 and reduce the transmitted forces. The inner portion of the axial portion 18 includes a first set of discs 20 attached through splines.

The outlet bell 10 is provided with a sleeve 21 mounted on the primary shaft 4 and provided, at its bore, axial grooves adapted to cooperate with corresponding splines of said shaft for the transmission of a torque to the tree 4.

The sleeve 21 also comprises, at a free end, a first radial portion 22 extending in the vicinity of the radial portion 16 of the bell 9. The radial portion 22 is extended by a second substantially radial portion 23. Said second portion 23 is here reported on the first portion 22 by welding. Of course, it is also possible to make the bell 10 in one piece, by stamping and folding a blank sheet of steel. The second radial portion 23 is extended, from a free edge of large diameter, by axial protuberances 24 extending on the opposite side to the inlet bell 9 and circumferentially spaced from each other. The protuberances 24 are arranged radially between the primary shaft 4 and the axial portion 18 of the inlet bell 9.

On the first radial portion 22 of the outlet bell 10 is attached a stop disk 25 in frictional contact with opposed radial surfaces of the portions 16 and 22 of the bells 9 and 10. Alternatively, it may be possible to replace this disc friction by a needle stop, or a suitable surface treatment.

The control member 11 is mounted to slide axially on the outlet bell 10, via a guide ring 27 mounted on the outer cylindrical surface of the sleeve 21 of said bell. For this purpose, the control member 11 comprises a sleeve 26 provided with a bore inside which said ring 27 is mounted.

The sleeve 26 is extended, at an axial end located in the vicinity of the radial portion 22 of the outlet bell 10, by a radial collar, itself radially extended by a portion

28. The substantially radial portion 28 is here reported by welding.

The portion 28 has a radial dimension substantially equal to that of the radial portion 23 of the outlet bell 10. The portion 28 is extended axially, in the direction of said bell 10, by protuberances 29 spaced circumferentially relative to each other.

The protuberances 29 are dimensioned and arranged so as to be located circumferentially between the protuberances 24 of the outlet bell 10. Each protuberance 29 is extended to from its free end by a radial flange 30 extending outwards towards the axial portion 18, being disposed axially close to the radial portion 17 of the inlet bell 9.

On the outer portions of the protuberances 29 are provided grooves axially slidably receiving a second series of discs 31. The flanks 30 are located axially between the discs 31 and the radial portion 17 of the inlet bell 9. The flanks

30 are able to bear against said discs 31, via a first flat washer-shaped pressure plate 30a, fixed on the sidewalls so as to allow the discs 20, 31 to be clamped and the transmission a couple between the input and output bells 9 and 10.

For this purpose, a second plate 30b of pressure, in the form of a flat washer, is also mounted on the protuberances 29. The plate 30b is axially opposite the plate 30a, considering the discs 21. The second plate 30b is positioned axially by the intermediate of an elastic ring 32, for example of the circlip type, mounted on the protuberances 24 of the outlet bell 10.

In order to allow clutch and clutch maneuvers, a control stop 33 is mounted on the sleeve 26 of the control member 11. The stop 33 can be actuated via a fork 34 to slide axially the control member 11 on the outlet bell 10. In a rest position of the stop 33, the flanks 30 exert an axial force on the discs 20, 31, to maintain the clutch 3 in the closed position.

For this purpose, the clutch 3 comprises at least one elastic member 35, mounted here between the radial portion 28 of the control member 11 and the radial portion 23 of the outlet bell 10. elastic 35 is located radially in the vicinity of the protuberances 24 and 29, and may for example be a helical spring.

In order to allow guiding of each elastic member 35, the clutch 3 also comprises at least one cylindrical centering pin 36, fixed on the radial portion 23 of the outlet bell 10 and at least one tubular guide 37 able to slide on said pawn. The guide 37 comes into frictional contact against the radial portion 28 of the control member 11.

One end of each elastic member bears against the radial portion 23 of the outlet bell 10, the other end being in contact with the radial portion 28 of the control member 11 via a collar radial friction of the guide 37.

Thus, each resilient member 35 mounted under prestressing exerts an axial force on the control member 11 in the direction of the clutch housing 2, making it possible to obtain a tightening of the discs 20 and 31. Alternatively, it could also be possible to provide an elastic member consisting of a diaphragm.

In order to obtain an amplification of the clamping force applied to the discs 20 and 31, the clutch 3 also comprises lugs 40 and seats 41 mounted on the control member 11 and on the outlet bell 10.

The lugs 40 and the seats 41 are here respectively disposed on the radial portion 28 and on the radial portion 23 in the vicinity of the elastic members 35, being offset radially inwardly.

Of course, it is also conceivable to mount the lugs 40 on the outlet bell 10, and the seats 41 on the control member 11. As illustrated in FIG. 2, each lug 40 comprises a convex surface 40a corresponding in shape with a concave surface 41a of the associated seat 41 forming a guide. The surfaces 40a and 41a comprise inclined ramps, for example between 30 ° and 60 ° relative to a direction of movement of the control member.

11 relative to the outlet bell 10, considering a plane of Figure 2 which is perpendicular to the plane of Figure 1.

In an engaged position, as shown in FIG. 1, the driving torque passes through the inlet bell 9 to the control member 11 via the disks 20, 31 which are in frictional contact with the with each other. The pair then passes from the control member 1 1 to the outlet bell 10, via the lugs 40 and seats 41. The primary shaft 4 is thus rotated about its axis 5. During the transmission of the torque between the control member

11 and the outlet bell 10, the surfaces 40a and 41a make it possible to cause the control member 11 to slide on the outlet bell 10 in the direction of the casing 2, which increases the clamping force applied to the disks. 20 and 31 initially applied by the elastic member 35, and this as soon as the instantaneous input torque exceeds the torque transmissible by the disks, said transmittable torque being an increasing function of the axial tightening force experienced by the disks.

The lugs 40 and the seats 41 thus form means for amplifying the clamping force applied to the disks 20 and

31 by ensuring the linear distance of the radial portion 28 of the control member 11 relative to the radial portion 23 of the outlet bell 10. To ensure the recovery of the axial forces exerted during the clutch and clutch maneuvers and to axially position the clutch 3 on the primary shaft 4 of the gearbox, there is also provided a needle stop 42 and a washer support 43 mounted between an axial end of the sleeve 21 of the control member 11 and the clutch housing 2, and a single adjusting washer 44 and a needle stop 45 disposed between the radial portion 16 of the bell input 9 and the flange 2a of said housing. The multi - disc clutch for a motor vehicle gearbox according to the invention is provided with an input bell integral with a rotation of an input shaft, of at least a first disk supported by the input bell, an output bell integral with rotation of an output shaft, at least a second disk, a mechanical control member for clamping the disks which is substantially coaxial with the exit bell, and Transformation elements of a rotational movement of the input bell into translation movement of the control member along said axis to amplify the clamping force applied to the discs.

Claims

Multidisk clutch for a motor vehicle gearbox, characterized in that it is provided with an input element (9), at least a first disk (20) supported by the input element, an outlet bell (10), at least a second disk (31), a mechanical control member (1 1) for clamping the disks which is substantially coaxial with the exit bell, the second disc (31) being supported by the control member (1 1), and means (40, 41) for amplifying the clamping force applied to the discs mounted on the exit bell and on the member control means, said means being able to allow a relative linear distance of the control member and the output bell along said axis, when transmitting a torque, the control member (1 1) sliding on the output bell (10) during transmission of the torque.

2-clutch according to claim 1, wherein the amplification means (40) mounted on the control member comprises a ramp (40a) inclined adapted to cooperate with a complementary ramp (41 a) of the amplification means (41). ) mounted on the outlet bell. 3-clutch according to claim 1 or 2, comprising elastic members (35) mounted between the outlet bell and the control member.

4-Clutch according to claim 3, wherein the control member (1 1) is configured to maintain, in a rest position, the clamping of the discs under the effect of the elastic members.

5-Clutch according to claim 3 or 4, comprising guides (37) for the resilient members and centering pins (36) of said guides. 6-clutch according to any one of the preceding claims, wherein the input element comprises an inlet bell (9) centered on an output shaft which is the primary shaft of the gearbox.

7-clutch according to any one of the preceding claims, provided with a single adjusting washer mounted between the input member and a clutch housing (2).

8-gearbox for a motor vehicle, comprising a clutch according to any one of the preceding claims.