JP2013092202A - Drum brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drum brake device which facilitates assembling of a brake shoe by retaining a bending part of a rim of the brake shoe which applies a braking force through friction engagement with a rotary drum, so as to be held between a spring material fixed to a backing plate and a ledge surface formed on a packing plate.SOLUTION: In the drum brake device, the brake shoe applying a braking force through friction engagement with the rotation drum is supported with pressure, against a backing plate. In the drum brake device, a spring material for holding the rim part in an intermediate part of a pair of brake shoes is fixed to the backing plate. The spring material and ledge surface formed on the packing plate hold the rim part of the brake shoe.

Description

  According to the present invention, a bent portion of a rim of a brake shoe that frictionally engages a rotating drum to apply a braking force is held so as to be sandwiched between a spring material fixedly fixed to the backing plate and a ledge surface formed on the backing plate. Thus, the present invention relates to a drum brake device that can easily assemble a brake shoe.

  FIG. 4 (a) is a plan view of a drum brake device having a conventional shoe hold-down device. A pair of brake shoes 3, 3 are mounted on the backing plate 1 by the shoe hold-down devices 4, 5, respectively. It is supported so as to press against it. The opposite ends of the brake shoes 3, 3 are in contact with the anchor portion 6 fixed on the backing plate 1, and the other ends of the brake shoes 3, 3 are connected to the wheel cylinder 7. A rotating drum (not shown) is disposed on the outer peripheral side of the brake shoes 3 and 3 with a predetermined gap, and the brake shoes 3 and 3 are frictionally engaged with the inner peripheral surface of the rotating drum by the operation of the wheel cylinder 7. By doing so, braking is performed.

  FIG. 4B is an AA enlarged cross-sectional view in FIG. 4A and shows one shoe hold-down device 5. Since the other shoe hold-down device 4 has the same structure and operation as the one shoe hold-down device 5, only one shoe hold-down device 5 will be described here.

  The shoe hold down device 5 includes a shoe hold pin 9, a pair of cups 10, 11 having a disc shape as a whole, and a compression coil spring 12 sandwiched between the two cups 10, 11. . The shoe hold pin 9 passes through the through hole 1a formed in the backing plate 1 and the notch 3b opening toward the inner peripheral edge of the shoe web 3a at the end 9b opposite to the head 9a. And the compression coil spring 12 is inserted between the shoe web 3a and the head 9a of the pin, so that the brake shoe 3 is pressed against the backing plate 1 with a predetermined preload and is attached so as to be expanded. ing.

  FIG. 4 (c) is an enlarged view of the portion X in FIG. 4 (a), and shows the engagement relationship between the shoe hold pin 9 and the upper cup 10. FIG. The head 9a of the shoe hold pin 9 has a horizontally long shape, and is assembled so that the engagement between the two is prevented by turning 90 degrees after passing through the long hole 10a formed in the center of the upper cup 10. I am doing.

  As shown in FIG. 4 (b), the through hole 1a formed in the backing plate 1 is braked to the extent that the shoe hold pin 9 is disengaged from the notch 3b of the shoe web 3a due to the expansion movement of the brake shoe 3 or the like. In order to prevent the shoe 3 from tilting toward the inner peripheral side, a cylindrical projection 1b is formed on the peripheral edge thereof by burring.

  By the way, apart from the above-described conventional shoe hold-down device, the present applicant has proposed a configuration in which the brake shoe is supported by a spring material in order to solve the later-described problems of the device (patent) Reference 1). As a brake shoe positioning mechanism composed of a single piece, there has also been proposed a shoe hold down device configured to support a single piece brake shoe with a cantilever spring (Patent Document 2).

JP 2003-130100 A Special table 2003-519766

  The above-described conventional shoe hold-down device is composed of four component parts including a shoe hold pin 9, two cups 10 and 11, and a compression coil spring 12, and the cup 10 is formed with a long hole 10a, and a pin head 9a. Has a special shape such as a horizontally long shape, and the backing plate 1 is subjected to burring processing. When the brake shoe 3 is assembled on the backing plate 1, the backing plate 1, the brake shoe 3, and the two cups 10 , 11 as well as 90 degree twisting work of the shoe hold pin 9 or the cup 10 is necessary, and not only cost for processing parts but also complicated work is required for assembly. .

  In addition, when the parking brake is provided in the drum brake of this form, it is necessary to consider that the parking brake lever does not interfere with the shoe hold pin at the time of design. As a result, in order to avoid interference with the pin on the parking brake lever itself. It is necessary to form a relief portion or to make the parking lever thinner. As a result, there arises a problem that the strength of the parking lever is insufficient.

  Furthermore, with the conventionally known shoe hold-down device configured as described above, it is extremely difficult to automatically assemble the brake shoe, and it is difficult to reduce the assembling cost.

  Moreover, although there are some which were shown by the said patent documents 1 and 2 as what can reduce a number of parts compared with the said prior art example, although this also has advantages, such as few parts number, the brake shoe of Since it cannot be automatically assembled, it is a big problem in streamlining the assembly work.

  The present invention has been made in view of such a situation, and an object of the present invention is to automate the work of assembling the brake shoe on the backing plate, and further, the interference between the parking lever and the shoe hold-down device. Accordingly, it is an object of the present invention to provide a drum brake device that can increase the width of the parking lever and consequently increase the strength of the parking lever. Further, the drum brake device of the present invention includes a spring material in which a rim portion of a brake shoe that frictionally engages a rotating drum to apply a braking force is fixed to a ledge portion formed on the backing plate and a ledge surface of the backing plate. Accordingly, an object of the present invention is to provide a drum brake device that can easily hold a brake shoe and reduce the number of parts by adopting a structure that can be held so as to be sandwiched.

Technical solutions adopted to solve the above problems are:
In a drum brake device that presses and supports a brake shoe that frictionally engages with a rotating drum and applies a braking force to a backing plate, the spring material that presses and holds a rim portion of an intermediate portion of a pair of brake shoes on the backing plate The drum brake device is characterized in that the rim portion of the brake shoe is sandwiched between the spring material and a ledge surface formed on the backing plate.
The drum brake device may be configured such that a rim portion of the brake shoe is positioned between a parking lever and a backing plate.
The spring material may be attached to a position corresponding to an intermediate portion of the left and right brake shoes disposed on the packing plate.
Further, the spring material fixedly fixed to the backing plate is fixedly fixed to the backing plate on the inner peripheral side with respect to the ledge surface, and the portion located on the ledge surface is separated from the ledge surface toward the outer peripheral direction. The drum brake device is characterized in that the bent end portion is separated from the ledge surface by the rim plate thickness.
Further, the spring material fixedly fixed to the backing plate is fixedly fixed to the backing plate on the inner peripheral side with respect to the ledge surface, and the portion located on the ledge surface is bent substantially parallel to the ledge surface toward the outer peripheral direction. Further, the drum brake device is characterized in that the end portion is further bent toward the ledge surface side than the portion bent in parallel.
In the drum brake device, the spring material may be a plate spring.

According to the present invention, the following effects can be obtained.
(A) According to the present invention, the spring material fixed and fixed in advance to the ledge portion of the backing plate is fixed and fixed on the inner peripheral side of the ledge surface, and the portion located on the ledge surface is directed toward the outer peripheral direction. Since the edge is bent away from the ledge surface and the end is further away from the ledge surface than the rim plate thickness, the rim bent portion of the shoe is smoothly placed between the spring material and the ledge surface when assembling the brake shoe. Can be inserted into.
(B) Since the shape of the spring material is the configuration described in (a) above, when assembling the brake shoes, the left and right brake shoes are resisted against the spring force of the return spring and are expanded on the backing plate. The brake shoe rim can be smoothly inserted between the ledge surface of the backing plate and the spring material by the urging force of the return spring, and the brake shoe can be assembled easily. Can be automated.
(C) When the brake shoe is assembled, the brake shoe rim is disposed and fixed so that it is positioned between the parking lever and the backing plate. It is not necessary to make the pin escape, and since the entire space up to the inner periphery of the rim can be used, the width of the parking lever can be increased and the required strength can be easily secured.
Thus, it is possible to achieve a specific function and effect.

It is a top view of the state which assembled | attached the brake shoe to the backing plate of this invention. It is a perspective view of the state which separated the backing plate assembly and the brake shoe assembly. It is AA sectional drawing in FIG. (A) is a perspective view of a spring material, (b) is a three-view drawing of a spring material. (A) is a perspective view of a spring material as another example, and (b) is a three-view drawing of the spring material. 4 (a), 4 (b), and 4 (c) are explanatory views of shoe holddown of a conventional drum brake.

  The present invention relates to a drum brake device that presses and supports a brake shoe that frictionally engages a rotating drum and applies a braking force to a backing plate. The backing plate presses a rim portion at an intermediate portion of a pair of brake shoes. A drum brake device in which a spring material to be held is fixed and fixed, and the rim portion is sandwiched between the spring material and the ledge surface formed on a backing plate. According to the present invention, the brake shoe is assembled. Since the rim part of the brake shoe is placed and fixed so that it is located between the parking lever and the backing plate, the parking lever does not need to be shaped to escape the shoe hold down pin as in the past. Also, since the space up to the inner circumference of the rim can be used, the parking lever Can take width larger, it is easy to secure the required strength. When assembling the brake shoes, place the left and right brake shoes on the backing plate in an expanded state against the spring force of the return springs, and then release the brake shoes. The force can be inserted smoothly between the ledge surface of the backing plate and the spring material, and the assembly of the brake shoe can be easily automated.

 Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a drum brake according to the present invention, and FIG. 2 is a perspective view showing a state in which a backing plate assembly and a brake shoe assembly according to the present invention are separated. 3 is a cross-sectional view taken along the line AA in FIG.

  In FIG. 1, the drum brake of the present invention has a pair of brake shoe assemblies 51, 51, which are arranged on a backing plate 52. The opposite ends of the brake shoes 51a, 51a abut on the anchor portion 53 fixed on the backing plate 52, and the other ends of the brake shoes 51a, 51a are connected to the wheel cylinder 54, so that the wheel cylinder 54 operates. As a result, the brake shoes 51a and 51a are expanded and frictionally engaged with an inner peripheral surface of a rotating drum (not shown), whereby braking is performed. In the figure, reference numeral 60 is a known spring, and 61 is a known strut assembly.

  2 and 3, a ledge surface 55 is formed on the backing plate 52 at a position corresponding to an intermediate portion between the two brake shoes 51a, 51a disposed on the backing plate 52. Here, the intermediate portion is in a substantially intermediate portion between the wheel cylinder and the anchor portion in FIG. 1 and is within a width of about ± 15 degrees with respect to the X axis. The ledge surface 55 is formed on the backing plate 52 by pressing or the like, and a spring material (in this example, a leaf spring) 56 is fixed and fixed 58 on the backing plate 52 on the inner peripheral side of the ledge surface 55. Yes. A rim bent portion (rim portion) 57 is formed in each brake shoe 51a provided with a friction material.

  2, 3, and 4, the spring material 56 is configured by bending a leaf spring, and the bottom of the leaf spring is located on the inner peripheral side of the ledge surface 55 of the backing plate 52 with spots, screws, rivets. It is fixed by an adhering means such as adhesion. 3 and 4, the spring material 56 has a rising portion 56 a that rises from the bottom, and is further bent from the rising portion toward the ledge surface 55 of the backing plate 52 (reference numeral 56 b). The end portion 56c located is separated from the ledge surface 55 toward the outer peripheral direction, that is, the end portion of the spring material 56 is separated from the ledge surface 55 from the rim portion (rim plate thickness) 57 of the brake shoe 51a. It is configured to be bent as it goes. By configuring the spring material 56 in such a shape, the rim portion of the shoe can be smoothly inserted between the spring material 56 and the ledge surface 55 when each brake shoe 51a is assembled.

  The thing of the form shown in FIG. 5 can be used as another example of a spring material. As shown in FIG. 5, the spring member 65 has a rising portion 65a that rises from the bottom, and is further bent from the rising portion toward the ledge surface 55 of the backing plate 52 (reference numeral 65b). The end portion 65c of the portion 65b is bent toward the ledge surface side of the portion bent in parallel to the ledge surface. By providing the bent portion 65c in this way, the middle portion of the shoe can be elastically supported, and the rotational behavior of the shoe can be effectively suppressed.

  Specifically, in the case of the two shoes as exemplified here, when the brake is not applied, the middle portion of the shoe is most likely to move away from the backing plate most easily, and this is suppressed. For this, it is effective to dispose a spring material in the middle part of the shoe.

  In order to assemble the brake shoe assembly 51 on the backing plate 52 using the spring material 56, in FIG. 2, the left and right brake shoes 51a, 51a are first moved to the left and right against the urging force of the return spring 59 (in the drawing). It is expanded in the direction of arrows B and B) and arranged on the backing plate 52 in that state. At this time, since the rim portions of the brake shoes 51a and 51a are expanded to the left and right, the brake shoes 51a and 51a can be easily arranged on the backing plate 52 without interfering with the spring material 56 fixedly fixed to the backing plate 52. Thereafter, when the brake shoes 51a and 51a arranged on the backing plate 52 are unexpanded, the left and right brake shoes 51a and 51a return to the initial positions by the urging force of the return spring 59. At this time, the rims of the brake shoes 51a and 51a The plate thickness 57 is inserted between the spring material 56 and the ledge surface 55 of the backing plate 52, and both are easily assembled. As described above, in this example, the assembly work of the backing plate 52 and the brake shoe assembly 51 is facilitated, and automatic assembly is possible.

  Although the embodiments of the present invention have been described above, the shape, material, and the like of the spring material can be appropriately changed within the scope of the gist of the present invention. The type of drum brake is not limited to the leading / trailing type, but can be applied to, for example, a duo servo type. The specifications described in the examples are merely examples in all respects and should not be interpreted in a limited manner.

  INDUSTRIAL APPLICABILITY The present invention can be used for a vehicle field in which a brake is mounted, particularly for assembling a drum brake shoe assembly.

51 Brake shoe assembly 51a Brake shoe 52 Backing plate 53 Anchor part 54 Wheel cylinder 55 Ledge surface 56 Spring material 56a Standing part 56b Bending part 56c End part 57 Rim part (rim thickness)
58 Fixing and fixing 59 Return spring 60 Spring 61 Strut assembly 65 Spring material 65a Standing part 65b Bending part 65c End part

Claims (6)

In a drum brake device that presses and supports a brake shoe that frictionally engages with a rotating drum and applies a braking force to a backing plate, the spring material that presses and holds a rim portion of an intermediate portion of a pair of brake shoes on the backing plate A drum brake device characterized in that a rim portion of the brake shoe is sandwiched between the spring material and a ledge surface formed on the packing plate. The drum brake device according to claim 1, wherein the rim portion of the brake shoe is configured to be positioned between a parking lever and a packing plate. 3. The drum brake device according to claim 1, wherein the spring material is attached to a position corresponding to an intermediate portion between the left and right brake shoes arranged on the packing plate. The spring material fixedly fixed to the packing plate is fixedly fixed to the packing plate on the inner peripheral side with respect to the ledge surface, and the portion located on the ledge surface is bent away from the ledge surface toward the outer peripheral direction. The drum brake device according to any one of claims 1 to 3, wherein the end portion is configured to be separated from the ledge surface by a rim plate thickness. The spring material fixedly fixed to the packing plate is fixedly fixed to the packing plate on the inner peripheral side of the ledge surface, and the portion located on the ledge surface is bent substantially parallel to the ledge surface toward the outer peripheral direction, The drum brake device according to any one of claims 1 to 3, wherein an end portion is further bent toward the ledge surface side than the portion bent in parallel.   The drum brake device according to any one of claims 1 to 5, wherein the spring material comprises a leaf spring.

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