CA2101923A1

CA2101923A1 - Brake shoe

Info

Publication number: CA2101923A1
Application number: CA002101923A
Authority: CA
Inventors: Wilfried Schnack; Volker Fasbender
Original assignee: Individual
Current assignee: Textar GmbH
Priority date: 1991-02-16
Filing date: 1992-02-12
Publication date: 1992-08-17
Also published as: EP0570442A1; AU1198992A; KR970005073B1; DE59202254D1; BR9205623A; WO1992014945A1; JP3347726B2; KR930703555A; TR26032A; ES2073290T3; JPH06505084A; EP0570442B1; SK85593A3; PL169906B1; ZA921051B; DE4104812C1; CZ160093A3

Abstract

Abstract A brake pad In a brake pad comprising a lining support plate (1) and a frictional lining (2), as well as a damper shim (3) arranged on the side of the lining support plate (1) averted from the frictional lining (2) and being secured against displacement and twisting, it is provided that the lining support plate (1) and the damper shim (3) each have throughgoing recesses (5, 6, 7, 8) aligned with and adapted to each other, and that the recesses (7, 8) of the damper shim (3) have projections (9) pro-truding towards the lining support plate (1) and extend-ing at least over a portion of the recess, the projec-tions engaging the corresponding recesses (5, 6) of the lining support plate (1) with a fit that allows for a limited clearance of motion of the damper shim (3).

(Fig. 1)

Description

Translation of th~ PCT-application PCT/EP92/00297 as filed , Brake pad The invention is directed to a brake pad according to the precharacterizing part of claim 1 or 13, as well as to a cutting tool according to claim 19.

Known brake pads comprise a lining support plate and a friction lining, as well as a damper shim arranged on the side of the lining ~upport plate facing away from the friction lining and being secured against displace-ment and twisting.

Such a brake pad is known from DE-27 13 377 A, wherein the damper ~him is glued in between protruding edge portions of the support plate so that a positive connec-tion of the lining support and the damper shim is ob-tained. The known damper shim is clamped between the edge portions with a bias, thereby deteriorating the damping performance.

From ~E-34 25 406 A, a brake pad for a disk brake i6 known, wherein the damper shim is fixed to the outer periphery of the lining support plate by means of sheet metal parts rectangularly projecting from the edge.

From EP-0 373 333 A2, a brake pad i8 known that has a damper shim being arranged between a retaining spring and a lining support, the damper shim being secured on the lining support against displacement and twisting. In this case, the damper shim is held positively and in form fit on the lining support. To this end, the damper shim is provided with bowl-shaped bosses engaging re-cesses of the support plate. The bowl-shaped bosses have conically extending bowl walls that are subject to heavy wear at the rotating edges of the recesses of the sup-port plates. It is a further disadvantage that the fric-tion lining also comes into contact with the damper shim through the recesses when the damper shim is glued thereon, thereby causing possible undesired distortions of the damper shim relative to the lining support plate.

It is the object of the invention to develop a brake pad of the type mentioned initially such that the damping performance of the damper shim is optimized, while pro-viding a good fixing of the position of $he damper shim.

According to claim 1, the problem is solved by the pres-ent invention by providing the lining support plate and the damper shim, respectively, with two throughgoing recesses aligned with and adapted to each other; provid-ing the recesses of the damper shim with projections protruding towards the lining support plate and extend-ing over at least a portion of the circumference of the recess, with the projections engaging the corresponding reces6es in the lining support plate in a fit that al-lows a limited clearance of motion for the damper shim.
The damper shim, which adheres to a gummed lining sup-port plate by means of an adhesive coating, is position-ally aligned by the at least two mutually adapted re-cesses of the lining support plate and the damper shimby virtue of beads or projections of the receæses of the damper shim engaging the recesses of the lining support plate. Due to the fact that the damper shim al60 has 2 rece6s, the frictional lining pressed onto the lining support plate side facing the damper shLm, cannot press on the damper shim to distort the same, whereby the damping performance of the damper shim would be degrad-ed.

The movability of the damper shim within the rece6ses of the lining 6upport plate may be determined within close predetermined limits, the tolerance of movement of the damper 6him may be defined individually for different brake pad types.

Preferably, the recess in the lining 6upport plate is formed stepped, the recess widening ~owards the damper shim. The stepped design of the recess opening offers the advantage that even if excessive friction material should emerge through the recess, the same will ~ot contact the beads or projections of the recesses of the damper shim ~o that an abutment of the lining material on the damper shim is reliably prevented.

The projections of the recesses of the damper shim may encompass the entire circumference of the recess, there-by forming a bead that can form a stopper for any di-rection the damper shim may move.

Prefera~ly, the projections extend at right angles from the damper shim. The projections may then engage the reces~ in the predetermined fit, i. e. in the manner of a clearance fit, without there being a risk of a wear on the edges at the recess opening.

The recess opening of the lining support plate may be chamfered on the damper 6him side.

According to claim 13, a further solution to the objects provides that the lining support plate and the damper shim each have at least one throughgoing recess aligned with the respective other one, that the recess or the reces6es of the damper shim have at least two 6traight edges - seen in top plan view, that the straight edge6 extend oppositely inclined to each other relative to the radial axis extending through the axis of ymmetry of the lining 6upport plate, that the 6traight edge6 have tongue~ projecting towards the lining support plate and engaging corresponding recesses of the lining support plate with a fit that allows for a limited movement of the damper shim.

The invention allows to exactly fix the damper shim in its po~ition by means of the mutually aligned and adapt-ed throughgoing recesses, without any occurrence of distortions between the lining support plate and the damper shim, because a limited space for movement i8 left between the tongues projecting towards the lining support plate and engaging the recesses of the same, and these recesses. The damper shim is reliably prevented from slipping onto the support plate or being twisted, even when strong shearing and torsional forces occur in combination with the vibrations induced during a ~ra~ing operation.

The positional fixing of the damper shim is particularly advantageous when the brake pad becomes hot since, in this instance, the adhesive connecting the damper shim with the support plate softens, whereby the damper shim is actually floatingly supported on the lining support plate so that it is displaceable. The inventive solu-tions according to claim 1 and 13, respectively, allow for a positional fixing of the damper shim despite a floating arrangement of the damper shim.

It i8 an essential advantage of the tongues over deep-drawn ~eads that they are not susceptible to ruptures.
~, Advantageously, it i8 provided that the recesses in the lining support plate are circular. Such recesses of the lining support plate are technically easier to produce.

It may be provided that the recesses of the damper shim each have two parallel straight edges. Such rectangular recesses can be produced in one production step with a simple tool shaped like a gable roof.

Preferably, the recesses of the damper shim converge relative to each other in the radial direction. In such a geometrical arrangement of the recesses, the induction of forces from the damper shim into the lining support plat~ i8 more favourable under load conditions, the optimum angle of inclination depending on the brake type and being variable accordingly.

The cutting tool for making the recesses in the damper shim, according to claim 13, may advantageously be used to bend the tongues into their final position for the assembly step. Thus, additional tools for bending the tongues and, accordingly, an additional production step are eliminated. In particular, the recesses of the damp-er shim necessary for the positional fixing thereof are not made by punching, but by a combined cutting and bending process. No finishing work is needed for the recesses made this way.

The following is a detailed description of embodiments of the present invention with reference to the accom-panying drawings.

In the Fi~ures Fig. 1 is a brake pad with a damper shim glued thereon, Fig. 2 is a sectional view along line II-II in Fig. 1, Fig. 3 shows the lining support plate, Fig. 4 is a sectional view along line IV-IV in Fig. 3, Fig. 5 is a partial sectional view of a damper shim in the area of a recess, Fig. 6 is an embodiment with conical recesses in the lining support plate, Fig. 7 is a further embodiment of a damper shim, Flg. 8 is a damper shim with cut recesses for positional f lxing, Fig. 9 shows the cutting tool, Fig. 10 illustrates the punching of the damper shim contour with the recesses of the damper shim being cut simultaneously, Fig. 11 illustrates the connection of the damper shim and the lining support plate, Fig. 12 illustrates the position of the tongues in the recess of the lining support plate, and Fig. 13 illustrates a further embodiment of the damper shim.
-The brake pad illustrated in Fig. 1 con6ists of a liningsupport plate 1, accommodating a lining 2 on its one side and a damper shim 3 on the ~i~e averted from the lining 2. Preferably, the damper shim 3 is glued on the lining support plate 1.

Both the lining support plate 1 and the damper shim 3 of the embodiment shown in Fig. 1 each have at least two circular recesses 5, 7 and 6, 8 adapted to each other, the recesses 7, 8 of the damper shim 3 having projec-tions 9 protruding towards the lining support plate 1 and engaging the recesses S, 6 of the lining support pl~te. The rece6ses 7, 8 of the damper shim 3 are con-centric with the corresponding recesses 5, S of the lining support plate 1.

Fig. 2 illustrates an embodiment in which the lining support plate 1 has a stepped recess 6, the recess por-8 2101~23 tion 12 on the lining side having a smaller diameterthan the recess portion 10 on the damper shim side.
Moreover, the lining-side recess portion 1~ is of slightly conical design so that the recess opening in the lining-side recess portion 12 narrows towards the damper shim 3. The projections 9 of the damper shim 3 that may also consist of a crimp, engage the widened rece6s portion 12, the outer diameter~ of the projec-tion6 being smaller by a defined measure than the inner dimension of the damper-side recess portion 10 so that the damper shim 3, though being principally fixed in the reces6es 5, 6 of the lining support plate 1, still has the possibility of bi-axial movement defined by the predetermined play. Thus, the position of the damper shim 3 is fixed with sufficient accuracy and rigidity, yet the damping performance is not degraded by absolute positive and form-fit connections. This results in an improved vibration damping.

It is also essential in this context that, upon pressing the brake lining 2 onto the support, the brake lining may pass through the recesses S, 6 by different extents without coming into contact with the damper shim 3, whereby the damping performance thereof would be deteri-orated.

Fig. 3 illu~trates the lining support plate 1 with the recesses 5, 6. It should be noted that circular recesses 5, 6, 7 and 8 are particularly suitable, yet the princi-ple of inserting the damper shim 3 into the recesses of the lining support plate 1 with a predetermined fit may also be applied to other kinds of recess ~hapes.

Further, the rece66es 5, 6 in the lining support plate 1 may be provided without 6teps but with walls extending rectangular to the 6urface of the lining support plate.

In a further embodiment without s$epped recesses 5, 6, the walls of the recesses 5, 6 may be conically enlarged towards the damper shim 3 80 that there will be no col-lision with the damper shim 3, even if lining material 2 should pass through the recesses 5, 6.

It is evident from the embodiment of Fig. 4, that the damper-~ide recess portion 10 is chamfered at the recess edge æo as to better prevent wear of the damper shim 3.

As can be seen in Fig. 5, the projections 9 of the damp-er shim 3 preferably project at right angles from the damper shim 80 that even in the case where the damper-side recess openings of the recesse~ 5, 6 are not cham-fered, wear of the damper ~him is largely prevented.

It is also essential that the projections 9 do just not contact the recess walls of recesses 5, 6 but are spaced therefrom by about 0.2 to 0.5 mm, for example.

With stepped reces6es 5, 6 of the linin~ support plate 1, the projections 9 are at a sufficient distance from the steps 80 that even when axial forces are taken up, it is ensured that the projections 9 of the damper shim do not contact the lining support plate 1 in the axial direction.

The recesses 5, 6, 7, 8 may also have a polygonal outer contour so that they may simultaneou~ly 6erve a6 a con-10 21~923 trivance against turning. In this case, one recess inthe damper shim 3 and the lining support plate 1, re-spectively, may be sufficient.

Fig. 7 illustrate6 a further embodiment of a damper shim 3 with specially designed recesse6 7, 8. The recesses 7, 8 consist of a substantially circular punched out hole 14 that is interrupted by tongues 16, however, which, in this embodiment, are arrangsd at an angular distance of 90' 80 that two tongues 16 face each other, re~pective-ly, in a recess 7, 8. The tongues 16 are bent by 90 relative to the surface of the damper shim 3 and enter the respective circular or polygonal recess 5, 6 ~f the lining support plate 1. In the embodiment of Fig. 7, the projections 9 consist of the rectangular flat tongues 16.

Fig. 8 illustrates a damper shim 3 fnr a brake pad con-sisting of a lining support plate 1 and a friction lin-ing 2, which damper shim i~ preferably glued onto the side of the lining ~upport plate 1 averted from the friction lining 2.

Both the lining support plate 1 and the damper shim 3 each have two mutually aligned recesses 5, 7 and 6, 8, the recesses 7, 8 of the damper shim 3 having tongues 16 projecting towards the lining support plate 1 in the form of projections and being adapted to the recesses 5, 6, the tongues engaging the circular recesses 5, 6 of the lining support plate 1.

~he rece~se~ 7, 8 of the damper shim 3 are substantially rectangular, the 6hort sides having no tongues, while 11 210~3 the long sides of the rectangular recesses 7, 8 are provided with the already mentioned tongues 16 project-ing towards the lining support plate 1, the tongues forming straight edges 15 when seen in top plan view.

Preferably, the recesse~ 7, 8 are inclined towards each other at a small angle relative to the radial axis 18 of the disk brake belonging to the brake pad, the radial axis extending through the axis of symmetry of the brake pad; thereby, the recesses slightly converge radially outwardly.

The arrangement of the recesses 7, 8 in Fig. 8, i.e.
under two oppositely extenqing angles ~, ~ relative to the radial axis 18, is particularly suited for an ad-vantageous fixing of the damper shim in the radial di-rection of the disk brake.

Preferably, the angle of inclination to the radial axis 18 is within the range from 0 to 5 and is set individ-ually for each vehicle and each type of brake. The angle to be selected may depend on the following parameters:
lining size, lining rigidity, frictional conditions and frictional forces.

The tongues 16 of the recesses 7, 8 are movable within a tolerance with respect to thP reces~es 5, 6 so that the narrow lateral end faces 17 of the tongues 16 will not contact the recesses 5, 6 in a condition free of forces acting, whereby the damping performance of the damper shim is not impaired.

12 ~101923 Under loaded conditions, a two-point contact of the tongues 16 occurs within the recesses 5, 6 so that a favourable induction of forces into the lining support plate 1 may occur and a slipping of the damper ~him 3 onto the lining support plate 1 is reliably prevented.

The position of the damper shim 3 is thus fixed with sufficient accuracy and fixedness, the damping perfor-mance not being impaired by positive or form-fit connec-tions. This results in an improved vibration damping.

As evident from Fig. 11, the frictional lining 2 cannot come into contact with the tongues 16 when the damper shim 3 i8 glued into the recesses 5, 6 of the lining support plate 1 60 that the damping performance of the damper shim 3 cannot be degraded by the frictional lin-ing 2.

Fig. 10 illustrates the production step for making the damper shim 3 with punching tools 22 that define the outer contour of the damper shim 3, as well as with cutting tools 20 that do not punch, but cut the recesses 7, 8 of the damper shim 3. The associated cutting tool 20 with its cutting tip is shown in perspective view in Fig. 9. The cutting tip has the shape of a gable roof, similar to the roof of a house standing upside down. The cutting tool forms a double T-shaped cut with a main cutting line in the center between the straight edgeR 15 and two further cutting lines extending orthogonal thereto and being made by the lateral front edges of the cutting tool 20, the further cutting lines intersecting the short sides of the substantially rectangular reces~es 7, 8 without forming tongues 16.

Due to the special design of the cutting tool 20, the two tongues 16 are simultaneously formed as a double T-shaped cut during the cutting operation and are bent when the cutting tool 20 moves deeper so that two pro-duction steps, namely punching and bending, are replaced with one single cutting step using a single cutting tool 20.

After the cutting tool 20 has been withdrawn, the tongues may spring back slightl~ 80 that the desired clearance between the tongues 16 and the walls of the recesses 5, 6 is left, while simultaneously retaining the optimum positioning of the damper shim 3.

In the embodiment of Fig. 13, only one recess, e.g. a triangular one with an isosceles or equilateral rela-tionship of the sides, may be provided wherein only the legs of equal length have tongues 16 or all straight edges 15, in the case of a equilateral recess.

In particular with an equilateral relationship of the sides of the tongues 16 triangularly engaging the re-cesses 5, 6, the axis of symmetry, extending through the point of the tongues 16 forming a triangle, may take an angle of inclination a, ~ relative to the radial axis 18, given an arrangement of the recesses 7, 8 in symme-try with the radial axis 18.

The damper shim 3 may additionally have a rubber coating on one or both sides that may particularly dampen the vibrations transferred by a brake piston.

Claims

1. A brake pad comprising a lining support plate (1) and a frictional lining (2), as well as a damper shim (3) arranged on the side of said lining support plate (1) averted from said frictional lining (2) and being se-cured against shearing;

characterized in - that said lining support plate (1) and said damper shim (3) each have throughgoing recesses (5, 6, 7, 8) aligned with and adapted to each other, and - that the recesses (7, 8) of the damper shim (3) have projections (9) protruding towards said lining support plate (1) and extending at least over a portion of said recess, said projections engaging the corresponding recesses (5, 6) of said lining support plate (1) with a fit that allows for a limited clearance of motion of said damper shim (3).

2. The brake pad of claim 1, characterized in that said recesses (5, 6) are formed stepped in said lining sup-port plate (1) and have a recess portion (10) being enlarged towards said damper shim (3).

3. The brake pad of claim 2, characterized in that the lining-side recess portion (12) tapers conically towards said damper shim (3).

4. The brake pad of claim 1, characterized in that said recesses (5, 6) in said lining support plate (1) taper conically towards said damper shim (3).

5. The brake pad of one of claims 1 to 4, characterized in that said projections (9) extend around the entire circumference of said recess.

6. The brake pad of one of claims 1 to 5, characterized in that said projections (9) extend at right angles from said damper shim (3).

7. The brake pad of one of claims 1 to 6, characterized in that said recess opening (14) of said lining support plate (1) is chamfered on its damper shim side (3).

8. The brake pad of one of claims 1 to 7, characterized in that said damper shim (3) is glued to said lining support plate (1).

9. The brake pad of one of claims 1 to 8, characterized in that said recesses have a polygonal outer contour.

10. The brake pad of one of claims 1 to 8, characterized in that said lining support plate (1) and said damper shim (3) each have at least two recesses (5, 6, 7, 8) with circular contour.

11. The brake pad of one of claims 1 to 8, characterized in that said projections (9) consist of a plurality of tongues (16) spaced a equal angular distances from each other, said tongues projecting from a circular punched hole (14) of the respective recess (7, 8) and engaging a circular or polygonal recess (5, 6) of said lining support plate (1).

12. The brake pad of claim 11, characterized in that said tongues (16) are rectangular in shape.

13. A brake pad for a disk brake with a lining support plate (1) symmetric relative to a plane of said disk brake that is parallel and orthogonal to the rotational axis of said disk brake and with a frictional lining (2), as well as a damper shim (3) arranged on the side of said lining support plate (1) averted from said fric-tional lining (2) and being secured against shearing;

characterized in - that said lining support plate (1) and said damper shim (3) each have at least one throughgoing recess (5, 6, 7, 8) aligned with each other, - that, in top plan view, said recess or said recesses (7, 8) of said damper shim (3) have at least two straight edges (15), - that said straight edges (15) extend oppositely in-clined relative to the radial axis (18) extending through the axis of symmetry of said lining support plate (1), and - that said straight edges (15) have tongues (16) pro-truding towards said lining support plate and engaging the corresponding recesses (5, 6) of said lining support plate (1) with a fit that allows for a limited clearance of motion of said damper shim (3) in a direction paral-lel to said edges (15).

14. The brake pad of claim 13, characterized in that the inclination of the straight edges (15) relative to the radial axis (18) is under an angle of 0° to 5°.

15. The brake pad of claim 13 or 14, characterized in that said recesses (7, 8) each have mutually parallel straight edges (15) having tongues (16) provided there-on.

16. The brake pad of one of claims 13 to 15, character-ized in that said straight edges (15) of said recesses (7, 8) of said damper shim (3) converge outward relative to each other in radial direction.

17. The brake pad of claim 13, characterized in that said recesses (7, 8) have three straight edges (15), the tongues (16) of which triangularly engage said recesses (5, 6).

18. The brake pad of one of claims 13 to 17, character-ized in that said recesses (5, 6) of said lining support plate (1) are circular and that the clearance of motion exists between the lateral ends (17) of said tongues (16) and said recesses (5, 6) of said lining support plate (1).