FR2746873A1 - VEHICLE CLUTCH STOPPER AND CONTROL FORK ASSEMBLY - Google Patents

Abstract

The ends of the branches (2a) of the fork (2) have a flat surface (5) vis-à-vis each corresponding bearing zone (4) of the stop (1). Between this surface (5) and said bearing zone (4) is interposed a pad (6) of moldable rigid synthetic material, with a low coefficient of friction, this pad (6) having on one side a flat surface (7) able to slide on said flat surface (5) of the corresponding end of the fork branch (2a) during the pivoting of the latter, and on the opposite side a surface of revolution (8) with an axis parallel to the pivot axis Y of the fork, this surface (8) being adapted to pivot on a surface of complementary shape (4a) of said bearing zone (4) of the stop, during said pivoting of the fork (2). Application: automobiles.

Description

VEHICLE CLUTCH STOP ASSEMBLY AND

ORDER FORK

  The present invention relates to an assembly comprising a clutch stop associated with axial guide means and with control means for its central bearing on the diaphragm of a clutch, these control means comprising a pivoting fork, the ends of the branches can push on

support zones of said stop.

  The clutch bearing may be of any known type, for example of the ball type frequently used now,

said in constant contact.

  A problem usually arises in assemblies of the aforementioned kind, that of friction and wear at the level of the contact between the ends of the branches of the fork and what has been called above.

the "abutment support zones".

  Indeed, while the stop slides axially on its axial guide means (guide tube), the ends of the legs of the fork in contact with the bearing support zones of the stop move in an arc of circle, which is

  the cause of the aforementioned friction and wear.

  We have already tried to solve this problem by

  interposition of a low-coefficient material cushion

  friction friction between flat bearing zones of the clutch bearing and the curved ends of the arms of the fork, these ends being able to pivot in a concave cylindrical part of each bearing while an opposite flat face of each bearing slides against the corresponding flat support zone of the stop; this solution however has the drawback of requiring a convex pivoting support of complementary cylindrical shape on the ends of the legs of the fork, which in turn

  complicates manufacturing and makes it more expensive.

  The purpose of the present invention is to solve the

  problem without the disadvantages of this known technique.

  To this end, the assembly of the general type defined above is characterized, in accordance with the invention, in that said ends of the branches of the fork have

  a flat surface vis-à-vis each corresponding support zone

  laying of the stop, and in that between this surface and said support zone is interposed a pad of rigid moldable synthetic material, with a low coefficient of friction, this pad having on one side a flat surface suitable for sliding on said flat surface of corresponding end of fork leg when swiveling

  of the latter, and on the opposite side a surface of revolution-

  tion of an axis parallel to the pivot axis of the fork, this surface being able to pivot on a surface of complementary shape to said abutment support zone,

  during said pivoting of the fork.

  This avoids any hollow or raised form, specially machined, on the ends of the legs of the fork, which greatly facilitates manufacture, and reduces the cost. The plastic shoe can slide through surfaces

  contact points, on the end of the corresponding branch

  dante of the fork, the pivoting then taking place,

  via parallel axis revolution surfaces

  lele to the pivot axis of the fork, between this shoe

  and the corresponding bearing zones of the stop.

  These cylindrical surfaces of revolution can be convex on the pads and concave on the abutment support zones, but it is preferable, from the point of view of manufacture, to provide them, on the contrary, concave on the

  skids and convex on the abutment support zones.

  An assembly according to the invention can therefore be further characterized in that on the side opposite its flat sliding surface on the flat surface of the end of the corresponding fork leg, the shoe has a concave surface of revolution, said surface of complementary shape of the abutment support zones being consequently convex. According to another arrangement of the invention, each shoe is kept pivoting on the corresponding support zone of the stop by a stirrup or by legs coming from molding.

  An embodiment of the invention is described below.

  below by way of non-limiting example, with reference

  Reference to the figures of the attached drawing in which: - Figure 1 shows in profile an assembly according to the invention in the clutch position; - Figure 2 is a similar view after pivoting of the fork, showing the assembly in the disengaged position; - Figure 3 is a perspective view of the guide portion of the stop, which carries the support zones; - Figure 4 is an elevational view of the stirrup; and - Figure 5 is a perspective view of the plastic shoe, this figure showing at the same time the possibility of a variant allowing to dispense with said stirrup. In these figures, there is shown in thin lines the guide tube mentioned above and which is integral with the gearbox casing, this casing carrying a ball joint 3. The clutch bearing, for example of the ball type, is referenced 1 and the fork, for example made of sheet metal, is referenced 2, its branches being referenced 2a. This fork is pivotally mounted, along an axis Y, on the aforementioned ball joint 3. The bearing zones of the stop are referenced 4 and have convex cylindrical parts 4a with axes parallel to the pivot axis Y of the ball joint 3 , itself orthogonal to the axis XX of axial displacement of the stop 1. The ends of the branches 2a of the fork 2 have a flat surface 5 with respect to the

support zones 4 of the stop.

  In this way, the action of the ends of the branches 2a of the fork on the support zones 4 of the stop 1 can

  be performed with the interposition of pads 6 such as shown

  felt: each shoe 6 has on one side a flat surface 7 suitable for sliding on the flat surface 5 of the corresponding end of the fork leg, and on the opposite side a concave cylindrical surface 8 suitable for pivoting on the support zone corresponding 4 of the stop. The comparison of FIGS. 1 and 2 shows the double displacement of the pads 6: in rotation on the zones 4 and in sliding on the flat surfaces 5 when the clutch pedal is actuated. Although the pads 6 can remain trapped between the ends of the fork legs and the stop, their assembly can be facilitated by attaching them to

  the support zones 4 by stirrups 9.

  The pads 6 may be of any suitable material.

  required with low coefficient of friction, moldable and good wear resistance. For this purpose, and only by way of example, it is possible to use PTFE, Delrin, a

  fiber-reinforced polyamide, and any material of the same type.

  In FIGS. 1 and 2, the stirrup 9 is distinct from the shoe 6. In a similar manner to a clothespin spring, the stirrup 9 generally has a U shape, as shown in FIG. 4, the bottom 9a of which is engaged in a groove 10

  practiced centrally in the flat surface 7 of the shoe 6.

  The free ends of the branches of the U each have a return 9b parallel to the bottom 9a. The returns 9b are engaged elastically in the ends of a hole 11

crossing each support zone 4.

  In the perspective view of FIG. 5, a variant has also been shown which makes it possible to dispense with a metal stirrup 9: according to this variant, the pad 6 has on its two opposite lateral faces tabs 9 'molded (shown in dashes), each of which carries at its free end a lug 9'b directed inward, the two lugs of the same shoe can thus engage elastically in the two ends of the holes

through 11 of the support zones 4.

Claims (4)

  1. Assembly comprising a clutch stop associated with axial guide means and with control means for its central bearing on the diaphragm, these control means comprising a pivoting fork whose ends of the branches can exert a thrust on bearing zones of said stop, characterized in that said ends of the legs (2a) of the fork (2) have a flat surface (5) with respect to each corresponding bearing zone (4) of the stop (1), and in that between this surface (5) and said bearing zone (4) is interposed a pad (6) of rigid moldable synthetic material, with a low coefficient of friction, this pad (6) having on one side a flat surface (7) suitable for sliding on said flat surface (5) of the corresponding end of fork leg (2a) during the pivoting of the latter, and on the opposite side a surface of revolution (8) axis parallel to the pivot axis (Y) of the idler rchette, this surface (8) being able to pivot on a surface of complementary shape (4a) of said bearing area (4) of the   stop, during said pivoting of the fork (2).   2. Assembly according to claim 1, characterized in that on said opposite side the shoe (6) has a concave surface of revolution (8), said surface (4a) of shape complementary to the bearing zones (4) of the stop ( 1) being consequently convex.   3. The assembly of claim 1 or 2, character-   laughed in that each shoe (6) is kept pivoting on the corresponding support zone (4) of the stop (1) by a stirrup (9) whose bottom (9a) is housed in a groove (10) of the flat surface (7) of the corresponding pad (6), the free ends of this stirrup each having a return (9b) parallel to said bottom (9a), the two returns of the same stirrup (9) thus being able to engage elastically in the ends of a through hole (11) in each support zone corresponding (4).   4. The assembly of claim 1 or 2, character-   laughed in that each shoe (6) has on its two opposite lateral faces molded tabs (9 ') each carrying at its free end a lug (9'b) directed inwards, the lugs of the same pad (6) which can thus engage elastically in the ends of a hole   through (11) of each corresponding support zone (4).