Drum brake assembly device, drum brake, and drum brake assembly method

Abstract

The present invention is an assembly device for a drum brake, a drum brake, and an assembly method for a drum brake with which it is possible to favorably assemble an elastic member and a hold-down pin to a back plate and a brake shoe of a drum brake through automatic assembly. An assembly device 21 includes: an inserting means 22 for holding a base end side of a hold-down pin 9 and inserting the hold-down pin 9 into a first insertion hole 2a formed in a back plate 2 and a second insertion hole 3d formed in a shoe web 3a; and a positioning means 23 for holding and positioning the inserted hold-down pin 9. The assembly device further includes a rotating means 24 that, after the hold-down pin 9 is positioned by the positioning means 23, rotates the hold-down pin 9 in a state in which holding of the hold-down pin 9 by the inserting means 22 and the positioning means 23 is released, to perform assembling.

Description

【Technical Field】 【0001】 The present invention relates to an assembling device for a drum brake, a drum brake, and a method for assembling a drum brake. More specifically, the present invention relates to an assembling device for a drum brake that automatically assembles an elastic member and a hold-down pin to a back plate and a brake shoe of a drum brake, a drum brake, and a method for assembling a drum brake. 【Background Art】 【0002】 Conventionally, in a drum brake for a vehicle, a pair of brake shoes are arranged opposite to each other on a back plate, and the brake shoes are elastically supported on the back plate via an elastic member and a hold-down pin. The assembly of the elastic member and the hold-down pin is generally performed manually. The shaft portion of the hold-down pin is inserted into insertion holes formed in the back plate and the brake shoe, and a base-end locking portion provided on the base-end side of the shaft portion is locked to the back plate, and a tip-end locking portion provided on the tip-end side of the shaft portion is locked to the elastic member (see, for example, Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2016-169780 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 However, in order to improve efficiency, when attempting to automatically assemble an elastic member and a hold-down pin as in Patent Document 1 described above using an assembling device, there is a gap between the back plate and the brake shoe, so it is necessary to regulate so that the hold-down pin does not fall during assembly. 【0005】 Therefore, the present invention aims to provide a drum brake assembly device, a drum brake, and a drum brake assembly method that prevent the hold-down pin from falling over during assembly and enable good assembly of the elastic member and hold-down pin to the drum brake back plate and brake shoe by automatic assembly. [Means for solving the problem] 【0006】 To achieve the above objective, the drum brake assembly device of the present invention is characterized by having, when assembling an elastic member and a hold-down pin to a brake shoe having a back plate and a shoe web, an insertion means for inserting the hold-down pin through a first insertion hole formed in the back plate, a second insertion hole formed in the shoe web, and the elastic member, and a positioning means for holding the hold-down pin inserted by the insertion means and positioning it in a predetermined position. 【0007】 Furthermore, the drum brake assembly method of the present invention is characterized in that, when assembling an elastic member and a hold-down pin to a brake shoe having a back plate and a shoe web, the method comprises an insertion step of inserting the hold-down pin through a first insertion hole formed in the back plate, a second insertion hole formed in the shoe web, and the elastic member; a positioning step of holding the hold-down pin inserted in the insertion step and positioning it in a predetermined position; and a rotation step of rotating the hold-down pin positioned in the positioning step to assemble it. [Effects of the Invention] 【0008】 According to the drum brake assembly device and assembly method of the present invention, it is possible to prevent the hold-down pin from falling over during assembly and to improve the ease of assembly by automatically assembling the hold-down pin. [Brief explanation of the drawing] 【0009】 [Figure 1] This is a front view of a drum brake illustrating a first embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of the line II-II in Figure 1. [Figure 3] This is a front view of the drum brake before the hold-down mechanism is assembled to the backplate and shoe web. [Figure 4] This is an explanatory diagram showing the first step in the assembly method of the present invention, which involves assembling a hold-down mechanism to the back plate and shoe web. [Figure 5] This is also an explanatory diagram showing the second step. [Figure 6] This is also an explanatory diagram showing the third step. [Figure 7] This is also an explanatory diagram showing the fourth step. [Figure 8] This is also an explanatory diagram showing the fifth step. [Figure 9] This is also an explanatory diagram showing the sixth step. [Figure 10] This is also an explanatory diagram showing the seventh step. [Figure 11] This is a front view of a drum brake showing a second embodiment of the present invention. [Figure 12] Figure 11 is a schematic cross-sectional view of the XII-XII line. [Modes for carrying out the invention] 【0010】 Figures 1 and 2 show a first embodiment of the drum brake of the present invention. The drum brake 1 has a pair of arched brake shoes 3, 3 arranged inside a back plate 2 fixed to the vehicle body, with one end of each brake shoe 3, 3 in contact with the piston 4a of the wheel cylinder 4 and the other end in contact with an electric actuator 5 for the parking brake. 【0011】 Between the two brake shoes 3, 3, return springs 6a, 6b are stretched between the inside of the foil cylinder 4 and the inside of the electric actuator 5, constantly biasing both brake shoes 3, 3 in the direction of reducing the diameter. Further, on the center side of the back plate of the return spring 6a on the foil cylinder 4 side, a brake clearance automatic adjustment device 7 is arranged to regulate the diameter-reducing position of the brake shoes 3, 3 outward and automatically adjust the braking clearance. 【0012】 The two brake shoes 3, 3 are formed in the same shape and used by being reversed, and are respectively formed by shoe webs 3a, 3a arranged parallel to the back plate 2, rims 3b, 3b fixedly provided in the intersecting direction outside the shoe webs 3a, 3a, and linings 3c, 3c adhered to the outer peripheral surfaces of these rims 3b, 3b. Further, at two locations respectively at substantially the middle positions of each shoe web 3a, 3a, hold-down mechanisms 8 are respectively provided, and the brake shoes 3, 3 are assembled to the back plate 2 through these four hold-down mechanisms 8. 【0013】 Each hold-down mechanism 8 is similarly configured and is composed of an elastic member 10 and the hold-down pin 9 for assembling the elastic member 10 to the side surface of the shoe web 3a on the side opposite to the back plate. 【0014】 The elastic member 10 includes a coil spring 11 arranged on the side surface of the shoe web 3a on the side opposite to the back plate, a retainer 12 arranged on the side of the coil spring 11 opposite to the back plate, and a cup 13 interposed between the side surface of the shoe web 3a on the side opposite to the back plate and the coil spring 11 for positioning the coil spring 11. 【0015】 Furthermore, four first insertion holes 2a for inserting the hold-down pins 9 are formed in the back plate 2. Also, two second insertion holes 3d for inserting the hold-down pins 9 are formed in each of the shoe webs 3a, 3a. Each of the first insertion holes 2a is formed at a position facing the four second insertion holes 3d when the brake shoes 3, 3 are assembled to the back plate 2. 【0016】 The retainer 12 includes a flange portion 12a placed on the upper part (opposite to the back plate side) of the coil spring 11 and a bowl-shaped insertion portion 12b inserted into the inner peripheral side of the coil spring 11. A locking hole 12c formed as a long hole is formed in the central portion of the insertion portion 12b. 【0017】 The cup 13 has a cup-shaped placement portion 13a for placing the coil spring 11 on the upper surface, a through hole 13b provided at the center of the placement portion 13a for inserting the hold-down pin 9, and an insertion piece 13c protruding from around the through hole 13b on the lower surface of the placement portion 13a. The placement portion 13a is formed to have a diameter slightly larger than the outer diameter of the coil spring 11, and when the coil spring 11 is placed on the placement portion 13a, the center of the through hole 13b and the central axis of the coil spring 11 coincide. 【0018】 The hold-down pin 9 includes a shaft portion 9a, a tip flat plate portion 9b (the flat plate portion of the present invention) provided at the tip of the shaft portion 9a, and a base end locking portion 9c provided at the base end of the shaft portion 9a. The tip flat plate portion 9b has a thickness that allows it to be inserted in the length direction of the first insertion holes 2a, the second insertion holes 3d, the through hole 13b, and the locking hole 12c, but cannot be inserted in the width direction of the locking hole 12c, and is formed in a substantially flat semi-circular shape. The base end locking portion 9c is formed to have a diameter larger than that of the first insertion hole 2a and in a conical shape that gradually increases in diameter toward the base end side. 【0019】 The hold-down pin 9, formed in this manner, has its base locking portion 9c locked to the back plate 2, its shaft portion 9a inserted through the first insertion hole 2a, the second insertion hole 3d, and the through hole 13b, and its tip flat plate portion 9b inserted through the locking hole 12c. By rotating the hold-down pin 9, the tip flat plate portion 9b is locked to the retainer 12. 【0020】 Next, the assembly device 21 for assembling the hold-down mechanism 8 to the back plate 2 and brake shoes 3,3 will be described based on Figures 4 to 10. 【0021】 The assembly device 21 is an assembly device for automatically assembling the hold-down mechanism 8 to the back plate 2 and brake shoes 3, 3, and includes an insertion means 22 that holds the base end locking portion 9c of the hold-down pin 9 and inserts the shaft portion 9a of the hold-down pin 9 into the first insertion hole 2a and the second insertion hole 3d, a positioning means 23 that holds the inserted shaft portion 9a and positions it in a predetermined position, and a rotating means 24 that rotates the hold-down pin 9 for assembly. 【0022】 The insertion means 22 includes a clamp portion 22a having a pair of arms facing each other across the opening, and a support portion 22b that abuts against the base end surface 9d of the hold-down pin 9 and supports the hold-down pin 9. The positioning means 23 is inserted between the back plate 2 and the shoe web 3a and includes chuck portions 23a, 23a (Figures 6 to 9) that hold the shaft portion 9a of the hold-down pin 9. 【0023】 The rotating mechanism 24 comprises a main body portion 24a and a rotating portion 24b that is rotatably and vertically movable through the main body portion 24a. The main body portion 24a has a through hole 24c that holds the rotating portion 24b rotatably and vertically, and a holding portion 24d for detachably holding the retainer 12 is provided on the outer circumference of the opening on the lower end side (shoe web side) of the through hole 24c. The rotating portion 24b is formed in a cylindrical shape with an outer diameter that can be inserted into the insertion portion 12b of the retainer 12, and has an insertion groove 24e (Figures 9 and 10) at its lower end (shoe web side end) through which the tip flat portion 9b of the hold-down pin 9 is inserted. 【0024】 Furthermore, the operation of the insertion means 22, the positioning means 23, and the rotation means 24 is controlled by a control unit (not shown). 【0025】 Next, with reference to Figures 3 to 10, the assembly method for attaching the hold-down mechanism 8 to the back plate 2 and brake shoes 3, 3 using the assembly device 21 will be described. The assembly of the hold-down mechanism 8 is performed in two stages: first, attaching one hold-down mechanism 8 to each of the left and right brake shoes 3, 3 simultaneously; and second, attaching the remaining two hold-down mechanisms 8 simultaneously in the same manner. Here, since each hold-down mechanism 8 is configured similarly, only the method for attaching one hold-down mechanism 8 will be described. 【0026】 As shown in Figure 3, in the pre-assembly process for the hold-down mechanism 8, the brake shoes 3,3, wheel cylinder 4, electric actuator 5, shoe return springs 6a,6b, and automatic braking gap adjustment device 7 are attached to the back plate 2, respectively. 【0027】 The assembly of the hold-down mechanism 8 begins with the first step shown in Figure 4, in which the insertion piece 13c of the cup 13 is inserted into the second insertion hole 3d, the mounting portion 13a of the cup 13 is positioned on the side of the shoe web 3a opposite the backplate, and then the coil spring 11 is placed on the mounting portion 13a. 【0028】 Furthermore, the insertion means 22 is moved to a position where the central axis of the hold-down pin 9 coincides with the central axes of the first insertion hole 2a and the second insertion hole 3d, while the clamp portion 22a of the insertion means 22 clamps the outer circumference of the base end locking portion 9c of the hold-down pin 9 and the support portion 22b is in contact with the base end face 9d of the hold-down pin 9. 【0029】 Furthermore, the flange portion 12a of the retainer 12 is held by the holding portion 24d of the rotating means 24, and the rotating means 24 is moved to a position where the central axis of the rotating portion 24b coincides with the central axes of the first insertion hole 2a and the second insertion hole 3d. 【0030】 Next, in the second step shown in Figure 5, the rotating means 24 is lowered toward the coil spring side, and the flange portion 12a of the retainer 12 is brought into contact with the upper part (opposite the back plate side) of the coil spring 11. 【0031】 Next, in the third step shown in Figure 6, with the chuck portions 23a, 23a still open, the positioning means 23 is inserted between the back plate 2 and the shoe web 3a. The chuck surfaces of the chuck portions 23a, 23a are positioned on the outer circumference side of the first insertion hole 2a and the second insertion hole 3d, respectively. 【0032】 Furthermore, the insertion means 22 is raised towards the coil spring side, and the hold-down pin 9 is inserted into the first insertion hole 2a (insertion process of the present invention). 【0033】 Next, in the fourth step shown in Figure 7, the insertion means 22 is raised further, and the hold-down pin 9 is inserted through the second insertion hole 3d, the through hole 13b, and the inner circumference of the coil spring 11, with the tip plate portion 9b positioned near the locking hole 12c of the retainer 12 (insertion step of the present invention). Then, the chuck portions 23a, 23a of the positioning means 23 are closed to hold the shaft portion 9a of the hold-down pin 9 (positioning step of the present invention). Furthermore, the clamp portion 22a of the insertion means 22 is opened to release the hold-down pin 9, and the hold-down pin 9 is supported by the support portion 22b. 【0034】 Next, in the fifth step shown in Figure 8, the rotating mechanism 24 is lowered in the direction of the shoe web while compressing the coil spring 11, and the flat tip portion 9b of the hold-down pin 9 is inserted into the insertion groove 24e of the rotating part 24b. 【0035】 Next, in the sixth step shown in Figure 9, the chuck portions 23a, 23a of the positioning means 23 are opened to release the hold-down pin 9. Then, the rotating portion 24b of the rotating means 24 is rotated 90 degrees to lock the tip flat portion 9b into the retainer 12 (the rotation step of the present invention). 【0036】 Next, in the seventh step shown in Figure 10, the retainer 12, which was held by the holding portion 24d of the rotating means 24, is released, and the rotating means 24 is moved upward to remove the tip flat plate portion 9b from the insertion groove 24e. Furthermore, the insertion means 22 is moved downward. 【0037】 Through the above steps, the coil spring 11 of the hold-down mechanism 8 is assembled while biasing the brake shoe 3 toward the back plate 2. 【0038】 As described above, the assembly device and assembly method of this embodiment reliably prevent the hold-down pin from falling over during assembly using the positioning means (chuck), thereby improving ease of assembly. Furthermore, by releasing the hold-down pin from being held by the insertion means and positioning means, and then rotating the hold-down pin with the rotation means to assemble it, the hold-down pin can be assembled easily and efficiently. 【0039】 Furthermore, the retainer 12 is provided with a locking hole formed by an elongated hole, and the hold-down pin has a flat plate portion at its tip that can be inserted into the locking hole, thereby improving the ease of inserting the hold-down pin. 【0040】 Furthermore, the assembly of the hold-down mechanism 8 can be done in two stages: first, by attaching one to each of the left and right brake shoes 3,3; second, by attaching the remaining two hold-down mechanisms 8; or by attaching all four hold-down mechanisms 8 simultaneously; or by attaching two hold-down mechanisms 8 simultaneously to one of the left or right brake shoes, and then attaching the remaining two hold-down mechanisms 8 simultaneously to the other brake shoe. 【0041】 Figures 11 and 12 show a drum brake 31 representing a second embodiment of the present invention. Components similar to those in the drum brake 1 of the first embodiment are denoted by the same reference numerals, and their detailed descriptions are omitted. 【0042】 The drum brake 31 has one end of each brake shoe 3, 3 in contact with the pistons 4a, 4a of the wheel cylinder 4, and the other end in contact with the anchor member 32. The hold-down mechanism 33 consists of a hold-down pin 9 and an elastic member 34 formed by bending a leaf spring into a U-shape. 【0043】 The elastic member 34 has a shoe web contact portion 34a that abuts against the side of the shoe web 3a opposite the back plate, and a bent portion 34b. The shoe web contact portion 34a has a third insertion hole 34c through which the hold-down pin 9 is inserted, and the bent portion 34b has a locking hole 34d. The shoe hold pin 9 has its base locking portion 9c locked to the back plate 2, its shaft portion 9a inserted through the first insertion hole 2a, the second insertion hole 3d, and the third insertion hole 34c, and its tip flat portion 9b inserted through the locking hole 34d. By rotating the hold-down pin 9, the tip flat portion 9b is locked to the bent piece 34b. In this embodiment, the drum brake 31 is also assembled using the assembly device 21 in a similar process to assemble the hold-down mechanism 33. 【0044】 Furthermore, the assembly device and assembly method of the present invention are not limited to the drum brakes of the above-described embodiments, but can be applied to any type of drum brake, such as those in which both ends of the brake shoes are in contact with the piston of the wheel cylinder. [Explanation of symbols] 【0045】 1...Drum brake, 2...Back plate, 2a...First insertion hole, 3...Brake shoe, 3a...Shoe web, 3b...Rim, 3c...Lining, 3d...Second insertion hole, 4...Wheel cylinder, 4a...Piston, 5...Electric actuator, 6a,6b...Shoe return spring, 7...Automatic braking gap adjustment device, 8...Hold-down mechanism, 9...Hold-down pin, 9a...Shaft part, 9b...Tip flat plate part, 9c...Base end locking part, 9d...Base end face, 10...Elastic member, 11...Coil spring, 12...Retainer, 12a...Flange part, 12b...Insertion Entry part, 12c...locking hole, 13...cup, 13a...mounting part, 13b...through hole, 13c...insertion piece, 21...assembly device, 22...insertion means, 22a...clamp part, 22b...support part, 23...positioning means, 23a...chuck part, 24...rotating means, 24a...main body part, 24b...rotating part, 24c...through hole, 24d...holding part, 24e...insertion groove, 31...drum brake, 32...anchor member, 33...hold-down mechanism, 34...elastic member, 34a...shoe web contact part, 34b...bending part, 34c...third insertion hole, 34d...locking hole

Claims

[Claim 1] A drum brake comprising a back plate fixed to the vehicle body, a pair of brake shoes provided on the inside of the back plate so as to be expandable, an elastic member that biases the brake shoes toward the back plate, and a hold-down pin inserted through the elastic member, wherein a first insertion hole for inserting the hold-down pin is formed in the back plate, and a second insertion hole for inserting the hold-down pin is formed in the shoe web of the brake shoe, wherein the drum brake assembly device assembles the elastic member and the hold-down pin to the back plate and the brake shoes, An insertion means for holding the hold-down pin and inserting the hold-down pin through the first insertion hole, the second insertion hole, and the elastic member, A drum brake assembly device characterized by having a positioning means for holding the hold-down pin inserted by the insertion means and positioning it in a predetermined position. [Claim 2] The drum brake assembly device according to claim 1, characterized in that, after positioning the hold-down pin with the positioning means, a rotating means is provided to rotate and assemble the hold-down pin while the holding of the hold-down pin by the insertion means and the positioning means is released. [Claim 3] The drum brake assembly device according to claim 1, characterized in that the positioning means includes a chuck portion inserted between the back plate and the shoe web and holding the hold-down pin. [Claim 4] A drum brake assembled by a drum brake assembly device according to claims 1 to 3, wherein the elastic member is provided with a locking hole formed by an elongated hole, and the hold-down pin is provided with a flat plate portion on its tip side that can be inserted into the locking hole. [Claim 5] The drum brake according to claim 4, wherein the elastic member comprises a coil spring disposed on the side of the shoe web opposite the back plate and a retainer disposed on the side of the coil spring opposite the back plate, and the locking hole is formed in the retainer. [Claim 6] The drum brake according to claim 4, wherein the elastic member is formed by bending a leaf spring into a U-shape and has a shoe web contact portion that abuts against the side surface of the shoe web opposite the back plate and a bent portion, and a third insertion hole for inserting the hold-down pin is formed in the shoe web contact portion and the locking hole is formed in the bent portion. [Claim 7] A drum brake comprising a back plate fixed to the vehicle body, a pair of brake shoes provided on the inside of the back plate so as to be expandable, an elastic member that biases the brake shoes toward the back plate, and a hold-down pin inserted through the elastic member, wherein the back plate has a first insertion hole for inserting the hold-down pin and the shoe web of the brake shoe has a second insertion hole for inserting the hold-down pin, and a method for assembling the drum brake, wherein the elastic member and the hold-down pin are assembled to the back plate and the brake shoes, An insertion step of holding the hold-down pin and inserting the hold-down pin through the first insertion hole, the second insertion hole, and the elastic member, A positioning step involves holding the hold-down pin in the inserted state after the insertion step and positioning it in a predetermined position, A method for assembling a drum brake, characterized by comprising a rotation step of rotating and assembling the hold-down pin that has been positioned by the positioning step. [Claim 8] The method for assembling a drum brake according to claim 7, characterized in that the rotation step is performed in a state in which the holding of the hold-down pin by the insertion step and the positioning step is released.

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