FR2629887A1 - SLIDING CALIPER BRAKE WITH MECHANICAL CONTROL - Google Patents

Abstract

A caliper 2 housed in the brake support 1 slides parallel to the axis of rotation of the wheel to be braked, with two branches 2 'and 2' ', which overlap a brake disc (not shown). A piston housed in the first branch 2 'is rigidly associated with a pressure plate 6 of a first jaw 4 carrying a brake lining 4'. A mechanically controlled spacer device is based on the piston and the first branch 2 '; a second jaw 3 placed on the second branch 2 '' carries a brake lining 3 '. Guides 8 are placed on the brake support 1 with a view to guiding and supporting the two jaws 3, 4.

Description

The present invention relates to a disc brake with sliding caliper with

  mechanical control, consisting of a fixed brake support, a caliper housed in the brake support, sliding parallel to the axis of rotation of the wheel to be braked, caliper with two branches, which overlap a brake disc integral in rotation with the wheel, with a piston housed in the first branch of the caliper, sliding parallel to the axis of rotation of the wheel, piston which is connected to a pressure plate, with a first jaw placed on the pressure plate,

  shoe that carries an applicable brake lining

  be one of the sides of the brake disc, of a mechanically controlled spacer device, which rests on the

  piston and on the first branch of the stirrup, a second

  me jaw placed on the second branch of the caliper, jaw which carries a brake lining-applicable against the other side of the brake disc and guides placed on the brake support for guidance and support of both

jaws. -

  In a sliding caliper disc brake of this type,

  described in document DE-OS 34 31 773, the pressure plate

  sion is connected to the piston via an adapter centering. This consists of a cylindrical projecting part, of low height, concentric on the surface

  front of the piston, projection which bites into a cy-

  the corresponding shallow indric of the pressure plate

  if we. The purpose of adaptation centering is to allow

  pendulum movements of the pressure plate, in order to

  Make sure that the corresponding brake lining comes over its entire surface in contact with the brake disc. We oppose

  thus asymmetrical wear of the brake lining.

  However, it appeared during the tests carried out that, under the effect of corrosion, fouling, deformations caused by the load and wear, manifested on the support of the jaws resistance to sliding, which

  opposed regular wear of the linings or prevented

drink it.

  The problem of the present invention is to improve

  the sliding caliper disc brake of this type, in the sense that despite the influences described, it forces

  the trim to regular wear by means of the

  ment of the shape of the piston in its bore.

  This problem is resolved in accordance with this

  invention, in that the pressure plate is rigidly connected

the piston.

  With the rigid connection of the piston with the pressure plate, a one-piece element is obtained, of which the

  center of rotation, compared to the form of realization

  known in two parts, is, during the process of

  braking, displaced relative to the lateral support of the

  brake choir and in relation to the brake surface. More precisely, the center of rotation moves on the one hand of the piston towards the external edge of the pressure plate forming an element with the piston and moreover , gets closer to the friction surface of the thickness

  pressure plate. Adjusting the shape of the pis-

  tone and pressure plate produced in the bore of the piston reduces the rotational torques which favor oblique wear, the pressure on the edge concerning the pilot piston not undergoing, in the zone of the normal coefficients of friction, no increase. But, for its part, adjusting the shape leads to the essential advantage that

  variations in the coefficient of friction and increases

  non-influencing resistance due to friction

  cannot be manifested unfavorably by

  the surface pressure reserves, so that the usu-

  re parallel is guaranteed over the entire thickness

of the filling.

  An example of a preferred embodiment of the present

  The invention is shown in the accompanying drawings and is

  explained more fully in the following.

  Figure 1 shows a top view, in section through

  tial, of a conventional sliding caliper disc brake, and Figure 2 is a representation similar to that

  of figure 1, which shows a disc caliper disc brake

  smoothing according to the present invention.

  The mechanically operated sliding caliper disc brake

  pic shown in the accompanying drawings consists of a brake support 1 fixed relative to the brake disc (not shown) and a caliper 2 housed in the sliding brake support parallel to the axis of rotation of the device

  that brake. Caliper 2 has two branches 2 'and 2 "overlapping

  singing the brake disc. A parallel sliding piston 5

  the axis of rotation of the brake disc is housed in

  the first branch 2 'of the stirrup 2. A spacer device

  mechanically controllable, which rests on the pis-

  tone 5 and on the first branch 2 'of the caliper, is used for the sliding of the piston 5. As soon as the configuration of this

  spacer is not in opposition to the pre-

  sente invention, there is no need to explain it here further. However, it should be noted that the DE-OS document

  31 42 799 gives all the details of such a device

  temento On the two sides of the brake disc are placed a first and a second shoe 3, 4, which respectively carry a brake lining 3 'and 4' applicable

  on the side of the brake disc facing it. The first-

  re jaw 3 is placed on the second branch 2 "of 1 '

  caliper 2 and the second jaw 4 on a pressure plate

  sion 6. The two jaws 3 and 4 are guided laterally along guides 8 of the brake support 1. These guides, when applying the brake absorb the forces which do not manifest and act parallel to the linings 3 'and 4' of brake. The pressure plate 6 is connected to the piston by an adaptation centering 10. This consists

  a cylindrical projecting part of low height,

  centered on the front surface of the piston 5, a projection which

  bites into a shallow cylindrical recess corresponding to

on the pressure plate 6.

  When the mechanical spacing device placed in the first branch 2 ′ of the stirrup 2 is actuated, the

  piston 5 is then set in motion yers the top,

  ment in Figure 1, until the lining 4 'placed on the second auxiliary jaw 4 comes into contact with the brake disc. The resulting reaction force has

  as a consequence that the entire stirrup 2 as well as the arrangement

  tif spacing is, relative to the brake support 1 moved downward, in accordance with Figure 1, until in the same way the lining 3 'placed on the

  first jaw 3 comes into contact with the brake disc.

  In the second jaw 4, having regard to the reports ac-

  tifs generated by the moment coming from the braking force

  ge FB on the brake surface and distance L'B from the

  port of the pressure plate 6 to the piston 5, asymmetrical wear occurs on the entry face of the disc

  brake. But, the relatively short axial length of the cen-

  adaptation trage 10 of the pressure plate 6 in the piston 5 allows a slight pendulum movement of the plate

  pressure 6, which must oppose asymmetrical wear

  than brake lining 4 '. However, it appeared

  during tests, that under the influence of corrosion,

  fouling and deformation caused by load and wear, there was stiffness on the jaw support A and that the eccentric application of the force was no longer sufficient to ensure absolutely regular wear of

the garnish.

  Figure 1 illustrates the forces generated during mid-

  brake application, which cause around the

  point P 'a pivoting of the assembly composed of the lining

  re brake 4 ', shoe 4 and pressure plate

  sion 6. This is the braking force FB acting

  on the brake lining 4 'and the corresponding pressing force

  laying FA as well as the friction force FR, which

  both act on the jaw 4. The force of rubbing-

  ment FR is here the product of the pressing force FA by the coefficient of friction with respect to the brake support 1. The force FQ with the lever arm lq represents the

  surface charge, which opposes forces and mo-

that come into play.

  The sum of all the moments having to be zero, we arrive at the following equality: I FA x A - FR x 1 '- FB x L'B + FQ (lq - 1') = 0 or FA x L ' A A xvx 1 '- FB x L'B + FQ (lq - 1') - O In the form of configuration according to the present invention shown in Figure 2 of the accompanying drawings, form

  in which the pressure plate and the piston are received

  nis in a single element 6, the assembly constituted by the brake lining 4 'and the jaw 4 pivots around the point P under the influence of the braking forces. Since,

  in this case too, the sum of all the moments must also

  In addition to being zero, the following equality follows: II FA x LA - FR x 1 FB x LB + FQ (lq - 1) = 0 or FA xLA - FAx rx 1 - FB x LB + 'FQ (lq - 1) = 0 Since, in the known embodiment of FIG. 1, the center of rotation P 'is located very close to the axis of the piston, this results in a large lever arm 1 q This means that the rise of the surface charge is low and the corresponding recall moment is low. Because, with equal values for FA, FB and FQ, the

  center of rotation P, according to the conforming embodiment

  me to the present invention, has been moved to the brake surface and to the jaw support A, all the lever arms which come into play are thereby shortened. A shorter lever arm 1 implies a rapid rise in the surface charge, here the recall time

  is high and therefore very regular wear is obtained

  the entire width of the brake lining.

  Since, in the embodiment according to the present invention shown in Figure 2, the center of rotation P is moved very close to the brake surface and the jaw support, and that all the lever arms

  shortened, the stiffness of the jaw support

  re have little influence on the regular wear of the lining. Thus, having regard to the active ratios generated by the moment of the braking force FB on the brake surface

  and the supporting force FA, as well as the friction force

  ment FR, asymmetrical wear occurs on the input side of the disc. This has the consequence that at the center of rotation P tun much higher resistant moment is

  generated by the application of an extremely eccentric force

  that, which opposes the asymmetrical wear of the lining. Departing from the embodiment shown, in which the pressure plate and the piston are formed as a single piece 6, these two pieces can

  also be rigidly connected by means of an as-

  semblageo This can be done by bolting or welding.

Claims (3)

  1. Disc brake 'With sliding caliper Mechanically operated   nique, consisting of a fixed brake support, a caliper housed in the brake support, sliding parallel to the axis of rotation of the wheel To be braked, caliper with two branches, which overlap a brake disc integral in rotation of the wheel, of a piston housed in the first branch of the sliding caliper parallel to the axis of rotation of the wheel, piston which is connected to a pressure plate, of a first jaw placed on the pressure plate , shoe which carries a brake lining which can be applied against one of the sides of the brake disc, of a mechanically controlled spacer device, which rests on the piston and on the first branch of the caliper, a second jaw placed on the second branch of the caliper, jaw which carries a brake lining applicable against the other side of the brake disc and of guides placed on the brake support for the purpose of guiding and supporting the two jaws, characterized in that the   pressure plate (6) is rigidly connected to the piston (5).   2. Disc brake A with sliding caliper Mechanically operated   screw according to claim 1, characterized in that the pressure plate (6) is rigidly connected to the piston (5)   by means of an assembly process.   3. Disc brake With sliding caliper Mechanically operated   screw according to claim 1, characterized in that the pressure plate (6) and the piston (5) are shaped as a one-piece item.