WO1997017551A1

WO1997017551A1 - Actuating devices for systems such as clutches or gearboxes

Info

Publication number: WO1997017551A1
Application number: PCT/FR1996/001760
Authority: WO
Inventors: Dominique Crasset
Original assignee: Dominique Crasset
Priority date: 1995-11-09
Filing date: 1996-11-08
Publication date: 1997-05-15
Also published as: FR2741128A1; AU7576296A

Abstract

A cyclic actuating device for systems such as clutches or gearboxes, comprising an input shaft (1), an output shaft and a dog interlocking system therebetween. The device includes a first rotary member (5) driven by the input shaft, a second rotary member (6) drivable by the first rotary member, and a third rotary member (7) driven by the second rotary member and arranged to drive the output shaft, said rotary members being movable with respect to one another; a control member (4) for causing mutual engagement of the first and second rotary members at the start of the cycle; and a first resilient means (8) which, as it is decompressed, presses the control member in a direction in which it causes mutual engagement of said first and second rotary members at the start of the cycle. Said rotary members are arranged to return the first resilient means to the compressed position at the end of the cycle.

Description

DEVICES FOR ACTUATING SYSTEMS SUCH AS CLUTCHES

OR GEARBOXES

The present invention relates to improvements to devices for actuating systems such as clutches or gearboxes.

Such a device is known from documents FR-A-2688747 and EP-A-0630495, the descriptions of which will be considered as an integral part of the present application. More specifically, the first of these documents describes a device for actuating a system such as a clutch or a gearbox associated with an engine, in particular for an automobile, and comprising control means and an actuating member. , this device further comprising:

- a first shaft driven in rotation by the motor,

- a second shaft secured to the actuating member,

- coupling means for coupling the second shaft to the first shaft under the action of the control means, - means for uncoupling the second shaft from the first shaft after a rotation of the second shaft by a predetermined angle, and

- return means for returning the second shaft to its initial position after its uncoupling from the first shaft.

More specifically, the second document provides means for keeping the coupling means coupled until the second shaft has rotated the predetermined angle.

Generally, the coupling means consist of a friction clutch. A problem then arises due to the wear of the members, discs or cones, of this clutch. This is the reason why the first aforementioned document suggests the use of dogs.

The present invention aims to provide means for using such dogs in a rational and efficient manner. To this end, the subject of the invention is a device for cyclically actuating systems such as clutches or gearboxes, of the type comprising an input shaft and an output shaft, and a dog-type fastening system between the two trees, characterized in that it comprises:

a first rotary member driven by the input shaft, a second rotary member capable of being driven by the first rotary member, and a third rotary member driven by the second rotary member and arranged to drive the output shaft, said rotary members being movable relative to each other,

a control member capable of bringing into engagement, at the start of the cycle, the first and second rotary members,

elastic means for pressing, by decompressing the control member in a direction in which it brings, at the start of the cycle, said first and second rotary members into engagement,

- Said rotary members being arranged to return, at the end of the cycle, said elastic means to the compressed position.

In a preferred embodiment, at least the first and second, or the second and third, rotary members, are arranged to cooperate by a combination of ramps.

Also in a preferred embodiment, said control member is a fourth rotary member and is arranged to cooperate with at least one stop member, said control member and said stop member being provided with a set of cooperating stop surfaces . More particularly, said control member may include a plate at the periphery of which are formed recesses arranged to cooperate with shoulders of the stop member.

In a particular embodiment, said first elastic means comprise a belleville washer bearing, on the one hand on a housing of the device and, on the other hand, on said control member, which is arranged to slide along the axis of said rotary members.

The device according to the invention may comprise second elastic means arranged to press said first rotary member in the direction of said control member It can also include third elastic means arranged to press said second rotary member towards said third rotary member.

It can also include means for automatically returning said control member to its cycle start position at the end of the cycle.

We will now describe, by way of nonlimiting example, a particular embodiment of the invention, with reference to the appended schematic drawings in which: - Figure 1a is a view in axial half-section of a device according to l invention, in its rest position, with a very developed partial developed view;

- Figures 1b, 1c, and 1d are views similar to Figure 1a illustrating the device in different phases of its operation; - Figure 2 is a perspective view of the control member and its stop members;

- Figure 3 is a perspective view on a larger scale of one of these stop members;

- Figure 4 is a top view of a part of the control member;

- Figure 4a is a view along arrow IV of Figure 4;

- Figure 5 is a front view of part of the device of the figures

1; Figure 6 is a sectional view along line VI-VI of Figure 5; and - Figure 7 is a view similar to that of Figure 1a, showing another embodiment.

FIGS. 1a to 1d show a device according to the invention with its input shaft 1 (equivalent to the shaft 4 of the aforementioned document EP-A-0630495) rotatably mounted in a housing 2, where it is driven to from the engine whose clutch or gearbox is to be actuated. A receiving tree

3 (equivalent to member 10 of the aforementioned document EP-A-0630495), and also mounted for rotation in the housing 2 in the extension of the shaft 1, the means of the present invention making it possible to drive at will the receiving shaft 3 from the input shaft 1, rotating at a predetermined angle.

Are also mounted in the housing 2, concentrically with the shafts 1 and 3 and in this order, a control member 4, and a first, a second and a third rotary members 5, 6 and 7 respectively. A Belleville washer 8 resting on the housing 3 presses the control member 4 in the direction of the first rotary member 5. Furthermore, the rotary member 5 is itself pressed towards the control member by an elastic washer 9 resting on a circlip mounted on the shaft 1. The control member 4 and the first rotary member 5 are therefore resting on each other by means of a bearing 10 and can move together axially.

Similarly, the second rotary member 6 is pressed towards the third rotary member 7 by a belleville washer 11. This third rotary member is fixed in axial translation relative to the housing 2 and to the shafts 1 and 3 and is linked in rotation to the shaft 3 by means of a disc type torque limiter 12 of known type.

Referring now to Figures 2 to 4, we see that the control member 4 has a cylindrical hub 13 secured to a plate 14 perpendicular to the axis of the hub. The plate 14 forms a projection 15 in which a hole 16 is drilled for receiving the end of a control rod (not shown), actuated for example by an electromagnet.

The periphery of the plate also forms, in three equally distributed locations, two recesses 17 and 18. Each recess 17 and 18 is formed at mid-thickness of the plate and the two recesses angularly overlap. Thus, the plate 14 forms, with its two faces and its recesses, four abutment surfaces 19 (face of the plate directed on the side of the hub), 20 (opposite face of the plate), 21 (surface of the recesses directed on the side of the hub) , and 22 (surface of recesses directed on the opposite side).

These abutment surfaces cooperate with the abutment surfaces 23 and 24 of abutment members 25 mounted integral with the housing 2 at the recesses 17,18. These surfaces 23 and 24 are formed vis-à-vis on two shoulders 26 and 27 of the members 25, the surfaces 23 facing surfaces 19 and 21 and the surfaces 24 facing surfaces 20 and 22. The shoulders 26 and 27 have radii slightly smaller than that of recesses 17 and 18 so as to be able to penetrate them.

The rotary member 5 is produced in the general form of a plate carrying at its periphery, on the side of the rotary member 6, two projections 28 forming ramps 29. The elastic washer 9 forms at its periphery two notches

30 in which the projections 28 are engaged and its central hole 31 is bordered by grooves 32 engaged on grooves 33 of the shaft 1. Thus, the rotary member 5 is integral in rotation with the shaft 1.

The second rotary member 6 is also produced in the general form of a plate, but it carries projections provided with ramps on its two sides. On the side of the rotary member 5, ramps 34 are arranged to cooperate with the ramps 29 and on the opposite side, ramps 35 are arranged to cooperate with ramps 36, carried by the third rotary member 7 and which face them. The device which has just been described operates in the following manner.

The device is shown in Figure 1a at rest. The belleville washer 8 pushes the control member 4 so that its abutment surface 19 is in abutment on the surfaces 23 of the abutment members 25. The grooved washer pushes the rotary member 5 against the stop 10, maintaining the teeth 29 and 34 away from each other. The rotational movement of the input shaft is not transmitted. It will be noted that the axial force of the washer 9 is less than that of the washer 8.

In FIG. 1 b, the control member 4 has been rotated using the electromagnet, so that it is the surfaces 21 which have come to bear on the surfaces 23, the control member 4 s 'being moved to the right and the shoulders 26 having engaged in the recesses 18. The rotary member has thus also moved to the right, pushed by the washer 8 via the member 4, against the action of the washer 9. The ramps 29 and 34 have just come into contact but, by the time the clearances have been caught up, the device still does not transmit any torque.

In FIG. 1 c, the angular clearances are taken up at the level of the ramps 29 and 34 and a torque and transmitted from the input shaft 1 to the receiving shaft 3. The torque passes through the two sets of ramps 29 , 34 and 35.36. This results in an axial reaction proportional to the helix angles of the ramps, a reaction which brings the surfaces 20 and 24 into abutment. Because of this abutment, the ramps cannot disengage. In FIG. 1 d, the control member 4 has been brought back using the electromagnet to its angular starting position where the shoulders 27 can engage in the recesses 17. The two sets of ramps 29, 34 and 35.36, still subjected to a torque, provide an axial force greater than that of the belleville washer 8 and push the control member 4 to the left of the drawing. During this push, and at first, the rotary member 6 comes into abutment (Belleville washer flat), then the ramps 29 and 34 disengage. At this instant, the surfaces 22 of the control member are opposite the surfaces 24, but without coming into contact. Since the ramps 29 and 34 are disengaged, the transmitted torque is zero, as is therefore the axial reaction. This allows the belleville washer 1 1 to return the rotary member 6 against the rotary member 7, and the belleville washer 8 to push the control member 5, the bearing 10 and the rotary member 5 to the right, against the thrust of the washer 9. This translation ends when the surfaces 19 and 23 come into contact and where we therefore find ourselves in the situation of Figure 1a.

It will be observed that the withdrawal of the member 6 towards the member 7 must be faster than the return of the control member 4 and of the rotary member 5 towards the member 6. This can be done on the mass parts, axial forces of the washers, friction. It is also possible to slow the return of the member 5 by emptying the volume 37 of oil through a calibrated orifice made either in the member 5 or in the washer 9.

In the embodiment of FIG. 7, the disengaging takes place automatically at the end of the stroke.

A finger 38 is mounted integral with the receiving shaft 3 and cooperates with a boss 39 of the control member 4 to return this member to its starting angular position when the receiving shaft has rotated by the desired angle.

Claims

1- Device for cyclic actuation of systems such as clutches or gearboxes, of the type comprising an input shaft

(1) and an output shaft, and a dog-type fastening system between the two shafts, characterized in that it comprises:

a first rotary member (5) driven by the input shaft, a second rotary member (6) capable of being driven by the first rotary member, and a third rotary member (7) driven by the second rotary member, and arranged to drive the output shaft, said rotary members being movable relative to each other,

- a control member (4) capable of bringing into engagement, at the start of the cycle, the first and second rotary members, - first elastic means (8) for pressing while decompressing the control member in a direction where it brings, at the start of the cycle, said first and second rotary members in engagement,

- Said rotary members being arranged to return, at the end of the cycle, said first elastic means to the compressed position. 2- Device according to claim 1, wherein at least the first and the second, or the second and third, rotary members, are arranged to cooperate by a combination of ramps (29,34, 35,36).

3- Device according to any one of claims 1 and 2, wherein said control member is a fourth rotary member and is arranged to cooperate with at least one stop member (25), said control member and said stop member being provided with a set of cooperating stop surfaces (19-24).

4- Device according to claim 3, wherein said control member comprises a plate (14) at the periphery of which are formed recesses (17,18) arranged to cooperate with shoulders

(26,27) of the stop member.

5- Device according to any one of claims 1 to 4, wherein said first elastic means comprise a belleville washer bearing, on the one hand on a housing (3) of the device and, on the other hand, on said control member, which is arranged to slide along the axis of said rotary members.

6- Device according to any one of claims 1 to 5, comprising second elastic means (9) arranged to press said first rotary member towards said control member

7- Device according to any one of claims 1 to 6, comprising third elastic means (11) arranged to press said second rotary member towards said third rotary member.

8- Device according to any one of claims 1 to 7, comprising means (38,39) for automatically returning said control member to its cycle start position at the end of the cycle