JP2007057027A - Brake shoe for drum brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake shoe adopted for a drum brake, which is reduced in manufacturing cost by reducing its manufacturing processes. <P>SOLUTION: A circularly curved rim part 2 and a web 3 bent in a L-shape from one side edge 2a of the rim part 2 and extending to the inside in the radial direction are integrally provided with press molding. The web 3 has an input part 5, a shoe holding part 8, an adjuster fitting part 9 and spring engaging parts 6, 7. Ledge abutting parts 10-12 for abutting on a ledge face 22 of a packing plate are formed by the web 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brake shoe for a drum brake in which the manufacturing process is reduced to reduce the manufacturing cost.

  A brake shoe for a drum brake mounted on a passenger car or a small truck is generally a combination of members obtained by press-forming steel plates.

  For example, a brake shoe known as a T-shaped brake shoe, as shown in FIG. 8, forms a shoe having a T-shaped cross section by welding and attaching a web 32 in the middle of the inner surface of the arc-shaped rim 31 in the width direction. A lining 33 is attached to the outer periphery of the rim 31 of the shoe to form a finished product. The web 32 is formed with a brake input portion, a shoe holding portion, an adjuster fitting portion, a spring engaging portion, and the like (all not shown).

  As shown in FIG. 9, a brake shoe (shown in the figure) adopting a shoe having a U-shaped cross section formed by integrally attaching a press-formed web 42 to both sides of a press-formed rim 41 by projection welding. 43 is also known as a lining).

  However, the T-shaped brake shoe and the brake shoe having a U-shaped cross section require a step of forming the rim and the web as a single unit and a step of welding both of them, which increases the number of manufacturing steps and increases the cost. There are drawbacks. Since the brake shoe of FIG. 9 has about 8 to 10 projection welds, the labor and time required for welding are less than that of the brake shoe of FIG. 8, but two members (rim and web) are used. Since a separate processing step and a welding step are indispensable, this structure also increases the cost.

  Therefore, as a measure for reducing the cost, a method of manufacturing a brake shoe only by a pressing process is adopted. A brake shoe manufactured by only the pressing process is disclosed in Patent Document 1 below, for example.

  The brake shoe is formed by bending a blank into an arc, and bending both sides of the blank toward the inside of the arc so that the cross-section is U-shaped. A flange part (web) that is continuous from side to side is generated. After that, both ends of the rim portion are folded inward in the radial direction, the folded portion and the end of the flange portion are overlapped and crushed, and the reinforced end portion (M-type reinforcing portion) is Cause it to occur. And the notch groove (groove for latching a strut) used as the input part of a parking brake is formed in the strengthened end.

  The brake shoe disclosed in Patent Document 1 omits the welding process, and is more productive than the welded brake shoe. However, since two steps are required for crushing both ends by the press, the effects of reducing the number of manufacturing steps and improving the productivity are not sufficient, and the cost reduction effect is reduced accordingly.

In addition, one end and the other end of the spring engagement part (mounting hole) is provided in one side flange (web), the spring engagement part on one end side and the spring on the anchor side on the spring engagement part on the other end side Each adjuster side spring is locked, but in this structure, the amount of offset from the reference position to the spring locking point with respect to the shoe increases, so the shoe must The moment of rotation in a direction different from the direction of rotation about the axis acts on the shoe, which adversely affects the durability of the ledge surface of the backing plate and the ledge contact portion on the shoe side that presses against the ledge surface.
JP 2002-227889 A

  An object of the present invention is to reduce the manufacturing cost by reducing the manufacturing process of the brake shoe.

  In order to solve the above problem, in the present invention, the rim portion of the brake shoe and the web are press-molded integrally. Specifically, a web that is bent in an L shape from the side edge and extends inward in the radial direction is provided by press molding at one side edge of the arc-shaped rim. The web is provided with an input portion (an input portion for parking brake for engaging the strut), a shoe holding portion and a spring engaging portion, and a ledge contact portion is formed by the web.

  If necessary, the web can be further provided with an adjuster fitting portion. The present invention can also be applied to a brake shoe of a drum brake having an anchor, and the brake shoe is provided with an engaging portion with the anchor and an abutting portion with respect to the anchor instead of the adjuster fitting portion.

  Note that the web may be either provided independently on one end side, the central portion, and the other end side of the rim portion, or provided as a series of webs.

  As an example of the brake shoe of the present invention, an input portion, a spring engagement portion, and a ledge contact portion are provided on the web on one end side of the rim portion, a shoe holding portion and a ledge contact portion are provided on the web of the rim portion central portion, and the rim portion It can be considered that a spring engaging portion, a ledge contact portion and an adjuster fitting portion are formed on the web on the other end side.

  The brake shoe forms a step in the rim width direction on the web provided on one end side and the other end side of the rim portion to form an offset portion and a non-offset portion with no bias on the other side edge side of the rim portion. It is preferable to provide the spring engaging portion at the offset portion of the web.

  In the brake shoe of the present invention, the rim portion and the web are formed by one press molding, so that the manufacturing process can be reduced to the minimum and the manufacturing cost can be reduced.

  In addition, if the web provided on one end side and the other end side of the rim portion is formed with an offset portion that is biased toward the other side edge of the rim portion and a spring engaging portion is formed on the offset portion, It is possible to suppress the action of a rotational moment in a direction different from the rotational direction, and the durability of the ledge surface and the ledge contact portion can be improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a drum brake brake shoe according to the present invention will be described below with reference to FIGS.

As shown in the figure, the brake shoe 1 of the present invention is made by integrally forming a rim portion 2 and a web 3 which are curved in an arc shape from a single plate-like blank by press working. Here, the web 3 is provided independently on one end side, the central portion, and the other end side of the rim portion 2. For convenience of explanation, the web on one end side is 3 ₋₁ , the central web is 3 ₋₂ , and the web on the other end side is 3 ₋₃ . Each of the webs _3-1 to _3-3 is formed on one side edge 2a of the rim portion 2, bent into an L shape, and extends toward the radially inner side (inside the arc of the rim portion 2). .

The web 3 _-1 at one end of the rim portion 2, an input unit 5 for a parking brake, the spring engaging portion 6 and the ledge contact portion 10 of the anchor side are respectively provided. In addition, the web 3 _-2 central portion of the rim portion 2, the shoe holding portion 8 and the ledge abutting portion 11 is provided, further, the web 3 _-3 at the other end of the rim portion 2, the adjuster fitting A portion 9, an adjuster-side spring engagement portion 7, and a ledge contact portion 12 are provided.

Exemplary brake shoe 1, the web 3 _-1 one end and the other end of the rim portion _2, 3 _-3 offset portion by causing a step in the rim width direction biased in the other side edge 2b side of the rim portion 13 and a non-offset portion 14 having no bias, respectively, and spring engaging portions 6 and 7 are provided in the offset portion 13 of this web, and the reference position of the spring locking point with respect to the shoe (center of the spring installation portion) C The amount of offset in the axle direction from (see FIG. 5) becomes almost zero or very small. For this reason, a rotational moment in a direction different from the original rotational direction does not act on the shoe. Even if the rotational moment is generated, it is negligibly small. Therefore, an excessive force is not applied to the ledge surface provided on the backing plate or the ledge contact portion provided on the shoe.

The input unit 5 and the adjuster fitting unit 9 are provided in the offset unit 13 of the webs 3 _-1 and 3 _-3 . Depending on the type of the drum brake, a brake shoe provided with an engagement portion with the anchor or a contact portion with respect to the anchor may be employed instead of the adjuster fitting portion 9.

  In the figure, reference numeral 15 denotes an anchor reaction force receiving portion. When the lining 4 is affixed to the outer peripheral surface of the rim portion 2 of the shoe configured as described above, the illustrated brake shoe 1 is completed. In this brake shoe 1, the web 3 is provided only on one side of the rim portion 2, so that the web 3 is provided as an independent web at three locations, particularly when the thickness of the material steel plate used is the conventional U-shaped. Although it may be thicker than that used for the brake shoe having a cross section, the increase in material cost due to this can be sufficiently absorbed by reducing the manufacturing process.

  The web 3 can be provided as a series of webs as shown in FIG. The series of webs 3 have an input portion 5, a spring engaging portion 6 and a ledge contact portion 10 at one end side, a shoe holding portion 8 and a ledge contact portion 11 at the center portion, and an adjuster fitting portion 9 at the other end side. The brake shoe 1 formed with the spring engaging portion 7 and the ledge contact portion 12 has the same rigidity and strength as the brake shoe provided with the web 3 independently of the brake shoe provided with the web 3 independently. Can be secured by using a thin plate material, which is advantageous in terms of material cost. As shown in the figure, the series of webs 3 in FIG. 6 are also formed with an offset portion 13 biased toward the other side edge 2b of the rim portion on one end side and the other end side, and spring engagement with the offset portion 13 is performed. It is preferable to provide the parts 6 and 7.

  An example of a drum brake using the brake shoe of FIG. 1 is shown in FIG. This drum brake is a duo-servo type parking brake and includes a pair of opposed brake shoes 1 and 1 each functioning as a leading shoe. Further, a brake operation mechanism 16, an adjuster 17, an anchor side spring 18, and an adjuster side spring 19 are provided. The pair of brake shoes 1, 1 are attached to a backing plate 21 using a shoe holddown 20 so as to be rotatable (swingable). The shoe hold down 20 is a well-known shoe holding means in which a cup, a pin, and a compression spring (all not shown) are combined. In FIG. 7, 23 is an anchor, and 24 is a drum.

  One of the brake shoes 1 and 1 is a primary shoe and the other is a secondary shoe. The strut 16b is engaged with the input portion 5 shown in FIG. 2 of the brake shoes 1 and 1, and the adjuster 17 is engaged with the adjuster fitting portion 9. Further, the anchor side spring 18 is engaged with the spring engaging portion 6, the adjuster side spring 19 is engaged with the other spring engaging portion 7, and the pin of the shoe hold down 20 is inserted into the hole of the shoe holding portion 8. With the force of the compression spring of the shoe hold down 20, the ledge contact portions 10 to 12 shown in FIG.

  The brake operating mechanism 16 is a parking brake input mechanism that combines a parking lever 16a, a strut 16b, a parking brake cable (not shown), and the like. , 1 lining 4 is pressed against the inner surface of the drum 24.

  Since this duo-servo type parking brake is well known, a detailed description of the operation and the like is omitted.

The present invention is not limited to a duo-servo type drum brake, for example, leading trailing (so-called LT), which is frequently used as a rear wheel brake that also serves as a parking brake.
) Type drum brakes and brake shoes used for two-leading type drum brakes.

The perspective view which shows an example of the brake shoe of this invention Front view of the brake shoe of FIG. Sectional view along line XX in FIG. Sectional drawing along the YY line of FIG. FIG. 1 shows the end of the brake shoe of FIG. 1 as viewed in the Z direction of FIG. The perspective view which shows the other example of the brake shoe of this invention Front view showing an example of a drum brake using the brake shoe of FIG. Sectional view showing an example of a conventional brake shoe The figure which shows the assembly procedure of the other example of the conventional brake shoe

Explanation of symbols

DESCRIPTION _OF SYMBOLS 1 Brake shoe 2 Rim part 3,3-1 -3-3 _-3 web 4 Lining 5 Input part 6,7 Spring engaging part 8 Shoe holding part 9 Adjuster fitting part 10-12 Ledge contact part 13 Offset part 14 Non-offset Part 15 Anchor reaction force receiving part 16 Brake operating mechanism 16a Parking lever 16b Strut 17 Adjuster 18 Anchor side spring 19 Adjuster side spring 20 Shoe hold down 21 Backing plate 22 Ledge surface 23 Anchor 24 Drum 31, 41 Rim 32, 42 Web 33, 43 Lining

Claims (5)

A rim part (2) curved in an arc shape and a lining (on the outer periphery of the rim part (2))
4) and a web (3) integrated with a rim portion bent in an L shape from one side edge (2a) of the rim portion (2) and extending inward in the radial direction. 3) is provided with an input portion (5), a shoe holding portion (8), and a spring engaging portion (6, 7), and further, a ledge contact portion (10 to 10) that contacts the ledge surface (22) of the backing plate. 12) A brake shoe for a drum brake, wherein 12) is formed by the web (3).   The brake shoe for a drum brake according to claim 1, wherein an adjuster fitting portion (9) is further provided on the web (3). The web (3) is provided independently on one end side, the central portion and the other end side of the rim portion (2), and the input portion (5) and the spring engagement are provided on the web (3 _-1 ) on one end side of the rim portion. The joint portion (6) and the ledge contact portion (10) are connected to the web ( _3-2 ) at the center portion of the rim portion, the shoe holding portion (8) and the ledge contact portion (11) are connected to the web on the other end side of the rim portion. (3 _-3) in a drum brake shoe brake according to claim 2, characterized in that formed adjuster fitting portion (9) and the spring engagement portion (7) and the ledge abutting portion (12), respectively.   The brake shoe for a drum brake according to claim 2, wherein the web (3) is provided as a series of webs.   On one end side and the other end side of the rim portion (2), an offset portion (13) biased toward the other side edge (2b) side of the rim portion is formed on the web (3), and the offset portion (13) The brake shoe for a drum brake according to claim 3 or 4, wherein the spring engaging portion (6, 7) is provided on the brake shoe.

Images