JP7829810B2 - Drum brake assembly device and drum brake assembly method - Google Patents

Description

This invention relates to a drum brake assembly device and a drum brake assembly method, and more specifically, to a drum brake assembly device and a drum brake assembly method for automatically assembling brake shoes onto a back plate.

Conventionally, drum brakes for vehicles have featured a back plate with a pair of brake shoes facing each other, with one end of each brake shoe in contact with the piston of the wheel cylinder and the other end with an anchor member. A return spring is stretched between the pair of brake shoes, constantly biasing both brake shoes in the direction of diameter reduction.

One method for assembling such drum brakes involved forming a temporary shoe assembly by temporarily attaching a return spring to a pair of brake shoes, and then automatically assembling this temporary shoe assembly onto a back plate to which a brake shoe expansion device was attached. For example, one method involved attaching a spring material for automatic assembly to the back plate, holding the shoe rim of the brake shoe in the temporary shoe assembly, inserting the shoe rim between the spring material and the ledge surface of the back plate to position it, and then automatically assembling the temporary shoe assembly onto the back plate (see Patent Document 1).

Patent No. 5330481

Generally, drum brake shoes are constructed by welding a shoe rim, to which the lining is attached, in a cross direction to the outside of a shoe web that is positioned parallel to the back plate. This can lead to variations in the finished product. Therefore, as described in Patent Document 1, if the shoe rim of a temporarily assembled brake shoe is held and assembled, there is a concern that product variations may affect the assembly accuracy.

Therefore, the present invention aims to provide a drum brake assembly device and a drum brake assembly method that can accurately assemble brake shoes to the drum brake backplate by automatic assembly.

To achieve the above objective, the drum brake assembly device of the present invention is characterized by comprising: a holding means that engages with an engaging portion formed on the shoe web of a shoe temporary assembly, in which a return spring is temporarily assembled to a pair of brake shoes, and holds the shoe temporary assembly in an expanded state; and a moving means that moves the holding means holding the shoe temporary assembly.

Furthermore, the drum brake assembly method of the present invention is characterized by comprising a holding step of engaging a holding means with an engaging portion formed on the shoe web of a shoe temporary assembly, which is a pair of brake shoes with a return spring temporarily attached, and holding the shoe temporary assembly in an expanded state, and a moving step of moving the holding means that holds the shoe temporary assembly using a moving means.

According to the drum brake assembly device and assembly method of the present invention, the retaining means is engaged with the shoe web of the shoe temporary assembly, and the shoe temporary assembly is held by the retaining means in an expanded state. This suppresses the impact of product variations on assembly accuracy, thereby improving assembly accuracy.

This is a front view showing an example of a drum brake. This is a schematic cross-sectional view of the line II-II in Figure 1. This is a front view showing the backplate in the preliminary assembly stage of the shoe assembly. This is a front view of the shoe assembly. This is a schematic diagram showing an expansion means of an assembly device illustrating one embodiment of the present invention, viewed from the planar side. This is a schematic diagram showing the holding and moving means of the assembly device as viewed from the side. This is a schematic diagram of the holding mechanism of the assembly device, viewed from the bottom.

Figures 1 and 2 show an example of a drum brake. The drum brake 1 has a pair of arched brake shoes 3, 3 arranged inside a back plate 2 fixed to the vehicle body.

Each brake shoe 3, 3 is formed from shoe webs 3a, 3a arranged parallel to the back plate 2, shoe rims 3b, 3b fixed to the outside of the shoe webs 3a, 3a in a direction intersecting them, and linings 3c, 3c attached to the outer circumferential surface of the shoe rims 3b, 3b. One end 3d, 3d of the shoe webs 3a, 3a is in contact with the piston 4a of the wheel cylinder 4 (the expanding device of the present invention), and the other end 3e, 3e is in contact with the operating parts 5a, 5a of the electric actuator 5 for the parking brake (the expanding device of the present invention).

Between the two brake shoes 3, 3, shoe return springs 6a and 6b (return springs of the present invention) are stretched between the inside of the wheel cylinder 4 and the inside of the electric actuator 5, constantly biasing both brake shoes 3, 3 in the diameter-reducing direction. Furthermore, an automatic braking gap adjustment device 7 is positioned on the center side of the back plate of the shoe return spring 6a on the wheel cylinder 4 side, which restricts the diameter-reduced position of the brake shoes 3, 3 outward and automatically adjusts the braking gap.

Furthermore, two hold-down mechanisms 8 for assembling the brake shoes 3, 3 to the back plate 2 are provided at approximately the midpoint of each shoe web 3a, 3a. Each hold-down mechanism 8 is similarly configured and consists of an elastic member 10 and a hold-down pin 9 for assembling the elastic member 10 to the side of the shoe web 3a opposite the back plate.

The elastic member 10 comprises a coil spring 11 positioned on the side of the shoe web 3a opposite the backplate, a retainer 12 positioned on the side of the coil spring 11 opposite the backplate, and a cup 13 interposed between the side of the shoe web 3a opposite the backplate and the coil spring 11 to position the coil spring 11.

Furthermore, the back plate 2 has four through holes 2a through which the hold-down pins 9 are inserted. In addition, approximately in the center of each shoe web 3a, a first through hole 3f (engaging part of the present invention) is formed on the wheel cylinder side for inserting the hold-down pins 9, and a second through hole 3g is formed on the electric actuator side for inserting the hold-down pins 9.

Next, the assembly device 31 for assembling the brake shoes 3, 3 to the back plate 2 will be described based on Figures 5 to 7. The assembly device 31 is an assembly device for automatically assembling a temporary shoe assembly 21 (Figure 4), which consists of brake shoes 3, 3, shoe return springs 6a, 6b, and an automatic braking gap adjustment device 7, onto the back plate 2 (Figure 3), to which the wheel cylinder 4 and electric actuator 5 are attached.

The assembly device 31 includes an expansion means 32 for expanding the shoe temporary assembly 21 against the spring force of the shoe return springs 6a and 6b, a holding means 33 for holding the shoe temporary assembly 21 in the expanded state, and a moving means 34 for moving the holding means 33.

As shown in Figure 5, the expanding means 32 includes a mounting portion 32a on which the shoe temporary assembly 21 is placed, an operating portion 32b, first contact portions 32c, 32c that contact one end 3d, 3d of the shoe web 3a, 3a of the shoe temporary assembly 21 placed on the mounting portion 32a, and second contact portions 32d, 32d that contact the other end 3e, 3e, respectively.

Each first contact portion 32c has a first contact surface 32e that contacts one end 3d of the shoe web 3a, and each second contact portion 32d has a second contact surface 32f that contacts the other end 3e of the shoe web 3a. Furthermore, the first contact surface 32e and the second contact surface 32f are formed with different shapes, for example, with different contact areas that contact one end 3d or the other end 3e.

The actuation unit 32b is, for example, a cylinder device. The actuation of one actuation unit 32b acts almost simultaneously on two first contact portions 32c and two second contact portions 32d, bringing the first contact surface 32e into contact with one end 3d of the shoe web 3a and the second contact surface 32f into contact with the other end 3e of the shoe web 3a. Further actuation of the actuation unit 32b moves the first contact portions 32c and the second contact portions 32d in the expanding direction of the brake shoe 3, causing the brake shoes 3, 3 to expand against the spring force of the shoe return springs 6a, 6b. Furthermore, because the shapes of the first contact surface 32e and the second contact surface 32f are different, the amount of expansion on one end of the shoe web 3a and the amount of expansion on the other end can be made different, allowing adjustment of the expansion amount even with the actuation of just one actuation unit 32b.

As shown in Figures 6 and 7, the holding means 33 comprises a pair of arm portions 33c, 33c, each having an inner diameter holding portion 33a inserted into a first through hole 3f of the shoe web 3a and a positioning portion 33b inserted into a second through hole 3g; a base 33d to which the pair of arm portions 33c, 33c are attached in an expandable manner; adjustment mechanisms 33e, 33e provided on the base 33d for adjusting the amount of expansion of the arm portions 33c, 33c; and a connecting portion 33f provided on the upper part of the base 33d.

The inner diameter holding portion 33a comprises a cylindrical insertion portion 33g inserted into the first through hole 3f, a plurality of chuck portions 33h protruding from the outer circumference of the insertion portion 33g, and a chuck drive mechanism 33i that extends and retracts the chuck portions 33h. When the insertion portion 33g is inserted into the first through hole 3f, the chuck drive mechanism 33i operates, causing the chuck portions 33h to protrude and press against the inner circumferential wall of the first through hole 3f, thereby holding the inner diameter (inner circumferential wall) of the first through hole 3f. The positioning portion 33b is formed of a pin member that can be inserted into the second through hole 3g.

The moving means 34 consists of a robot arm connected to the connecting portion 33f of the holding means 33.

Furthermore, the operation of the expanding means 32, the holding means 33, and the moving means 34 is controlled by a control unit (not shown) provided in the assembly device 31.

Next, an assembly method for assembling the brake shoes 3, 3 onto the back plate 2 using the assembly device 31 will be described based on Figures 3 to 7.

First, as shown in Figure 3, the wheel cylinder 4 and electric actuator 5 are attached to the back plate 2 by manual or mechanical assembly, and as shown in Figure 4, a temporary shoe assembly 21 is formed by attaching the shoe return springs 6a and 6b and the automatic braking gap adjustment device 7 to the brake shoes 3, 3.

Next, in the expansion step, as shown in Figure 5, the shoe temporary assembly 21 is placed on the mounting portion 32a of the expansion means 32, and the operating portion 32b is activated to bring the first contact portions 32c, 32c into contact with one end portion 3d, 3d of the shoe web 3a, and the second contact portions 32d, 32d into contact with the other end portion 3e, 3e of the shoe web 3a. The operating portion 32b is further activated to expand the brake shoe 3 against the spring force of the shoe return springs 6a, 6b. In addition, the automatic braking gap adjustment device 7 is extended as a result.

Next, as the first movement step, the holding means 33 is moved to the upper part of the shoe temporary assembly 21 via the moving means 34.

Next, the holding process will be explained using Figures 6 and 7. The arms 33c, 33c of the holding means 33 are expanded by the adjustment mechanism 33e, aligning the position of the first through hole 3f of the shoe web 3a with the position of the inner diameter holding part 33a, and inserting the inner diameter holding part 33a into the first through hole 3f. At this time, the position of the second through hole 3g and the positioning part 33b are also aligned, and the positioning part 33b is inserted into the second through hole 3g (positioning process of the present invention).

After the insertion portion 33g is inserted into the first through hole 3f, the chuck drive mechanism 33i operates, causing the chuck portion 33h to protrude from the outer circumference of the insertion portion 33g. The chuck portion 33h is then pressed against the inner circumferential wall of the first through hole 3f, thereby holding the inner diameter of the first through hole 3f. As a result, the temporary shoe assembly 21 is held by the holding means 33 in a positioned state with the brake shoes 3, 3 expanded.

Next, the operating part 32b of the expansion means 32 is activated to return the first contact parts 32c, 32c and the second contact parts 32d, 32d to their initial state. Then, in the second moving step (the moving step of the present invention), the holding means 33, which holds the shoe temporary assembly 21 as described above, is moved via the moving means 34 to the upper part of the back plate 2 to which the wheel cylinder 4 and the electric actuator 5 are attached. Furthermore, one end 3d, 3d of the shoe webs 3a, 3a is positioned near the pistons 4a, 4a of the wheel cylinder 4, and the other end 3e, 3e of the shoe webs 3a, 3a is positioned near the operating parts 5a, 5a of the electric actuator 5.

Next, in the release step, the chuck drive mechanism 33i is activated to return the chuck portion 33h to its initial state, the inner diameter holding portion 33a is removed from the first through hole 3f, and the positioning portion 33b is removed from the second through hole 3g, thereby releasing the connection between the shoe temporary assembly 21 and the holding means 33. Consequently, the brake shoe 3 of the shoe temporary assembly 21 is reduced in diameter by the spring force of the shoe return springs 6a and 6b, with one end 3d, 3d connected to the pistons 4a, 4a of the wheel cylinder 4, and the other end 3e, 3e connected to the operating portions 5a, 5a of the electric actuator 5, and the brake shoes 3, 3 are assembled to the back plate 2. Also, the automatic braking gap adjustment device 7 returns from its extended state to its initial state.

After the brake shoes 3, 3 are assembled to the back plate 2 in this manner, each hold-down mechanism 8 is assembled across the back plate 2 and the brake shoes 3.

As described above, according to the assembly device 31 and assembly method of this embodiment, the holding means 33 holds the inner diameter of the first through hole 3f formed in the shoe web 3a, and holds the shoe temporary assembly 21 in an expanded state during assembly. Therefore, variations in the product can be suppressed from affecting the assembly accuracy, and the assembly accuracy is improved.

Furthermore, in the positioning process, by inserting the positioning part 33b through the second through hole 3g formed in the shoe web 3a to position the shoe temporary assembly 21, it is possible to prevent the shoe temporary assembly 21 from shifting position during movement in the second moving process, thereby further improving ease of assembly.

Furthermore, the present invention is not limited to the above-described embodiment where one end of each brake shoe is in contact with the piston of the wheel cylinder and the other end with the operating part of the electric actuator. It may also be the case where both ends of each brake shoe are in contact with the piston of the wheel cylinder, or where one end of each brake shoe is in contact with the piston of the wheel cylinder and the other end with the anchor member.

Furthermore, the expanding means of the present invention is not limited to having four contact portions that abut one end and the other end of the shoe web, as in the above-described embodiment, with either a first contact surface or a second contact surface formed on each contact portion. It may also be provided with two contact portions that have both a first contact surface and a second contact surface, and these two contact portions expand the brake shoe 3.

1...Drum brake, 2...Back plate, 2a...Through hole, 3...Brake shoe, 3a...Shoe web, 3b...Shoe rim, 3c...Lining, 3d...One end, 3e...Other end, 3f...First through hole (engaging part), 3g...Second through hole, 4...Wheel cylinder (expansion device), 4a...Piston, 5...Electric actuator (expansion device), 5a...Actuating part, 6a, 6b...Shoe return spring (return spring), 7...Automatic braking gap adjustment device, 8...Hold-down mechanism, 9...Hold-down pin, 1 0...Elastic member, 11...Coil spring, 12...Retainer, 13...Cup, 21...Shoe temporary assembly, 31...Assembly device, 32...Expanding means, 32a...Mounting part, 32b...Operating part, 32c...First contact part, 32d...Second contact part, 32e...First contact surface, 32f...Second contact surface, 33...Holding means, 33a...Inner diameter holding part, 33b...Positioning part, 33c...Arm part, 33d...Base, 33e...Adjustment mechanism, 33f...Connecting part, 33g...Insertion part, 33h...Chuck part, 33i...Chuck drive device, 34...Moving means

Claims (6)

In a drum brake assembly device, a shoe assembly, in which a pair of brake shoes with a return spring temporarily attached is assembled to a back plate on which an expansion device for expanding the brake shoes is pre-installed, and the brake shoes are connected to the expansion device,
A holding means for holding the shoe temporary assembly in an expanded state against the spring force of the return spring,
A moving means for moving the holding means,
The shoe temporary assembly is provided with an expanding means for expanding the shoe ,
The retaining means engages with an engaging portion formed on the shoe web of the brake shoe to hold the shoe temporary assembly ,
The expanding means comprises an operating part and contact parts that contact both ends of the shoe web, respectively, when the operating part is operated.
The shape of the first contact surface of the contact portion that abuts against one end of the shoe web and the shape of the second contact surface of the contact portion that abuts against the other end of the shoe web are made different.
The assembly device for a drum brake is characterized in that the actuation part operates the contact part substantially simultaneously with the operation of a single actuation part . The drum brake assembly device according to claim 1, characterized in that the engaging portion is a first through-hole formed in the shoe web, and the retaining means is inserted through the first through-hole and includes an inner diameter retaining portion that holds the inner diameter of the first through-hole. The drum brake assembly device according to claim 2, characterized in that the retaining means is inserted through a second through-hole formed in the shoe web and includes a positioning part for positioning the retaining means and the shoe temporary assembly. In a drum brake assembly method, a shoe assembly, in which a pair of brake shoes and a return spring are temporarily attached, is assembled onto a back plate to which an expanding device for expanding the brake shoes is pre-installed, and the brake shoes are connected to the expanding device,
The expansion step involves expanding the shoe temporary assembly,
A holding step in which the shoe temporary assembly is held by the holding means by engaging the holding means with an engaging portion formed on the shoe web of the brake shoe, which is expanded against the spring force of the return spring,
A moving step of moving the holding means, which holds the shoe temporary assembly, to a predetermined position on the upper part of the back plate by the moving means,
The system includes a holding release step for releasing the holding state by the holding means,
The expansion step involves bringing contact portions, which contact both ends of the shoe web and have different shapes—a first contact surface that contacts one end of the shoe web and a second contact surface that contacts the other end of the shoe web—into contact with both ends of the shoe web by the operation of the operating part, thereby expanding the shoe temporary assembly.
The method for assembling a drum brake is characterized in that the actuation of one actuation part causes the contact part to act substantially simultaneously . The engagement portion is a first through-hole formed in the shoe web,
The drum brake assembly method according to claim 4 , characterized in that the holding step involves inserting the inner diameter holding portion into the first through hole and holding the inner diameter of the first through hole. The drum brake assembly method according to claim 5 , characterized in that the holding step includes a positioning step of inserting a positioning portion through a second through hole formed in the shoe web and positioning the holding means and the shoe temporary assembly.