FR2546248A1 - Cable control device for a clutch mechanism of the pulled type - Google Patents

Abstract

The clutch mechanism comprises a clutch release bearing 30 mounted slideably along a driven shaft 18 and adapted to intervene by traction on the elastic clutch engagement means 24 of the said mechanism, an axial drive component 40 of the release bearing 30 is harnessed at two diametrically opposed points 41, 42 to the ends of a control cable 43 passed over a return for coupling to a control member between two end sections 43A, 43B guided parallel to the said driven shaft. <IMAGE>

Description

 The present invention relates generally to clutch mechanisms of the so-called "pulled" type comprising a clutch release bearing mounted to slide relative to a driven shaft and adapted to act by traction on the elastic clutch means, in particular the fingers radials of a diaphragm forming in its peripheral part Belleville washer between cover and pressure plate of the mechanism.

 The control of declutching stops of this kind usually operates by means of a fork adapted to act on two diametrically opposite arms formed to have an effect on an appropriate piece for driving the stop.

 This arrangement raises various problems both from the point of view of design, manufacture and assembly and in terms of maintenance of the mechanism. These problems result in particular from the fact that the fork must pass through the clutch housing, bending stresses, wear problems at the points of attack, as well as friction at the articulation of the fork.

 The present invention offers a radical solution to avoid all of these difficulties thanks to a cable control particularly suitable for clutch mechanisms of the type under consideration.

 Cable controls have already been offered (cf.

in particular US Pat. No. 3,841,454), but in the context of a clutch of the advanced type and at the cost of undesirable complications resulting from the need to use means for transforming linear movements by rotation and vice versa.

 The cable control device proposed according to the invention is essentially characterized in that in a clutch mechanism of the pulled type comprising a clutch release bearing slidably mounted on the lcg of a driven shaft, an axial drive part of said stop clutch release is coupled at points diametrically opposite the ends of a control cable passed over a coupling gear to a control member between two end sections guided parallel to said driven shaft.

 Thanks to this arrangement one is led to a simple, reliable and space-saving device as which the comaiida cable can work exclusively in traction.

The characteristics and advantages of the invention will moreover derive from the description which follows, by way of example, with reference to the accompanying drawings in which
Figure 1 is a schematic view in axial section of a clutch mechanism equipped according to the invention
Figure 2 is a schematic perspective view of the clutch control associated with the gearbox
Figure 3 is a schematic view in axial section of another form of control of the clutch release bearing
FIGS. 4 to 6 are similar views showing other alternative embodiments,
According to the embodiment chosen and shown in FIG. 1, the invention is applied to a clutch mechanism 10 intended, in the usual way, for being mounted on a reaction plate ll partially and schematically shown, secured to the flywheel 12 d1a driving shaft 13, for example the crankshaft of an internal combustion engine propelling a motor vehicle. A friction disc 14 inserted between the reaction plate 11 and a pressure plate 20 is carried by a web 15 which is coupled via a shock-absorbing coupling assembly 16 to a grooved end portion 17 of a driven shaft 18, in this case the input shaft of a gearbox 19.

 Also usually, the clutch mechanism includes a cover 21, a generally annular part by which it is adapted to be attached to the reaction plate 11 and which has a central opening 22 on the front and around it an annular bead. 23 providing support for the peripheral zone of a diaphragm 24. The latter constitutes, by its peripheral zone, a Belleville washer exerting an elastic action between the support zone 23 on the cover, on the one hand, and a circular series of members support 25 provided for this purpose on the pressure plate 20, on the other hand. Radially inside this peripheral zone, forming elastic means of actuation of the pressure plate, the diaphragm is conventionally fragmented into radial fingers 26 which are adapted to cooperate by their radially internal ends with a clutch release bearing 30.

 This is a clutch of the so-called pulled type where the associated disengaging stopper is intended to act by pulling on the radial fingers 26 of the diaphragm in a direction tending to pull them in the direction of the gearbox 19.

 The declutching stop 30, which is conventionally equipped with a ball bearing 31 for this purpose comprises on the radially internal side a driving element 32 penetrating inside the clutch mechanism beyond the diaphragm and bearing opposite from the terminal part of the fingers 26 an annular attack piece suitable for driving these fingers towards the outside of the mechanism when the disengaging stopper is itself moved in direction. In view of this axial movement the stopper is mounted on a support annular or sleeve 34 adapted to slide on a guide 35 formed for this purpose around the shaft 18. From the radially outer side the support 34 is capped with a cover 36 of generally cylindrical shape enveloping the outer ring of the bearing 31 and having on its periphery a plurality of axial slots 37 in which are adapted to engage elastically a corresponding series of coupling tabs 38 formed for this purpose on the periphery of the support 34. The cover 36 presents Finally, opposite the gearbox 19, a flange or flange 40.

 The cover thus formed thus constitutes, with the sleeve 34, the element for operating the stop 30.

 To the flange 40 are coupled according to the invention the two ends 41 and 42 of a control cable 43.

Starting from these two coupling points 419 42, the two strands 43A and 43B of the cable first extend parallel to the shaft 18 through two passages 44Â, 44B formed for this purpose in the cover 45 of the box. speeds on either side of the bearing 46 of the input shaft 18. They then rise vertically to exit via the upper face of the box through two other passages 48A, 48B and meet on a part deflection 50 in the form of a half-pulley coupled in any manner suitable for a linkage (not detailed) for control from any declutching control member (pedal, jack, etc00) 0
Each of the passages 44 or 48 is naturally equipped according to current techniques, with a means suitable for ensuring the seal (O-ring for example) while allowing the cable to slide. Between the passages 44A, 44B, on the one hand, and the coupling points 419 42, on the other hand, can be advantageously inserted a bellows such as 51 for protection and confinement interposed between the flange 40 of the cover of the stop and the front wall 45 of the gearbox.

In its course inside the gearbox, the cable 43 is advantageously guided by means of sheath sections 53A, 53B placed in abutment by their ends opposite the entrances of the respective passages 44 and 48. It can therefore be, at least in the sections located inside the gearbox, cables of the type known as BOWDEN with flexible sheaths butted0
According to an advantageous arrangement of the invention, the guide ducts thus formed inside the gearbox (whether flexible gainas of the BOWDEN type or others) are perforated from place to place, as indicated in 55 , so that the gearbox lining oil can invade them and thus ensure lubrication favoring the smooth sliding of the cables on their route, and this up to the coupling points 41, 42 and up to the passages 48.

 The variant embodiment of FIG. 3 differs from the previous one by the fact that the clutch release bearing 30, instead of being fitted with a containment hood of the type previously considered, comprises radial arms 60 of the kind intended to allow the classic fork control.

The cable control is carried out here by means of an annular part 61 adapted, on the one hand, to bear by means of bosses 62 on the arms 60 of the stop in a diametral plane and on the other hand, a hitch by dÙX diametrically opposite zones at the ends 41, 42 of the control cable in a diametrical plane perpendicular to the previous one. Furthermore, the passages 44 provided in the pa rsi of the gearbox have, on the inner side9, abutment clearances of the cable guide sheath 53; while on the outside they are fitted with a double sealing system, for example an O-ring 64 lined with a scraper washer 65, beyond which the cable itself extends freely to its point of hitch on the stop.

 In the variant illustrated in Figure 4, the sheath 53 has an extension 53 'through the passage 44' of diameter enlarged as a result of the box beyond a butted projection 65. The sheath opens at 66 to the Inner of a flexible sleeve 67 for confining the oil and guiding the cable.

 In the variant of FIG. 5, there is provided a rigid traction column 70 coupled at 71 to the cable 43. On the outside, a flexible sleeve 72 is formed between two O-rings around the column rigidly coupled to an annular operating part 73 a stop of the so-called autocentreusa type adapted to cooperate in a manner known per se with a spring 74 for maintaining the self-centering.

 In the variant of FIG. 6, a guide column 80 is formed around the end part of the control cable which extends through the outlet passage 81 of the gearbox up to the hitch 85 on the stop. The sheath 82 of the cable's internal guide has an end portion 83 enlarged as a result. On the outside, there is a flexible sealing sleeve 84 extending from the outlet passage 81 Up to the hitch 85 on the stop.

 As it is easy to realize, whatever the details of embodiment of the cable control according to the invention, this cable remaining taut between, on the one hand, its control member 50 and, on the other hand, its two coupling points 41, 42, to the buoy maneuvering member, it works exclusively in traction.

The mounting of the device poses no significant problem for its part since it can operate outside the clutch housing by simple successive attachment of the two ex hoppers of the cable to the traction part.
The embodiments with rigidly guided end portions of the control cable according to FIG. 5 or 6 may be preferred in certain cases in consideration of the positive nature of the guidance obtained in the axial direction. Such guidance allows the tube to be saved if necessary. guide 35 of the stop with a corresponding simplification of the sleeve 34.

 In all cases, by an appropriate choice of passages 44 and 48, it is possible to allow the BOWDEN cable confined inside the gearbox to be deployed with a radius of curvature favorable to its proper functioning.

 According to a variant, the guide of the cable inside the gearbox can be ensured by means of a profile guide of semi-circular section adapted to support the cable on the radially inner side in its curvilinear path.

Claims (5)

 1. Cable control device for clutch mechanisms of the so-called pulled type comprising a clutch release bearing mounted to slide along a driven shaft and adapted to act by traction on the elastic clutch means of said mechanism, characterized in that an axial drive part (40,6l, 73 ..) of the declutching stop (30) is coupled at two diametrically opposite points (41, 42) at the ends of an operating cable (43) passed over a return coupling (50) to a control member between two end sections (43A, 43B) guided parallel to said driven shaft.

 2. Device according to claim 1, characterized in that the driven shaft (18) being the input shaft of a gearbox (19) the control cable passes through this box by two pairs of passages (44, 48) provided for this purpose in the casing thereof.

 3. Device according to claim 2, characterized by a guide by flexible sheath abutted (53) of the cable at least on its course carried out within the gearbox.

 4. Device according to claim 3, characterized in that the guide sheath is perforated.

 5. Device according to 1 t any one of the preceding claims, characterized in that the control cable is equipped with rigidly guided end portions (70,80) o