JPS628441Y2 - - Google Patents

Description

[Detailed description of the invention] This invention restricts the movement of the shoe assembly beyond what is necessary for its function, and prevents damage to the boot due to movement of the shoe assembly and separation of the shoe assembly from the wheel cylinder piston. The present invention relates to a shed-floating type drum brake that prevents this.

A shoe floating type drum brake generally includes a pair of shoe assemblies, one end of which is engaged with a piston of a wheel cylinder, and the other end of which is brought into contact with an anchor block. Furthermore, a shoe hold down device is attached to the center of the web of the shoe assembly to prevent the shoe assembly from floating up from the backing plate.

However, this shoe assembly does not have any fixed parts, so if it is subjected to a large impact during assembly to a vehicle or during transportation prior to that, the shoe assembly will move and detach from the wheel cylinder piston. Otherwise, there was a risk of getting stuck between the wheel cylinder piston and the wheel cylinder body and damaging the boot, etc. Such damage has a serious impact on brake performance, is extremely difficult to repair, and significantly reduces work efficiency, but no appropriate countermeasures have been taken in the past.

The present invention was developed against the background of the above-mentioned circumstances, and aims to provide a drum brake equipped with a device that restricts the movement of the shoe assembly beyond what is necessary for its function. The gist of this is that, in a shoe floating type drum brake, an engagement hole is formed near the end of the web portion of the shoe assembly on the side that comes into contact with the anchor block; An engagement piece whose tip end is substantially perpendicular to the web portion extends from a plate-like member fixed to the front or back side of the anchor block, and the tip of the engagement piece is loosely fitted into the engagement hole. The aim is to restrict the movement of the shoe assembly in the radial direction within a certain limit. The shoe floating type drum brake according to the present invention maintains the same function as a conventional brake, but by restricting the movement of the shoe assembly within a certain limit, it reduces the amount of shock that occurs before it is assembled into a vehicle. This succeeded in preventing separation from the wheel cylinder piston and damage to the boot, etc. due to movement of the assembly. Therefore,
This has the effect of increasing brake safety, eliminating troublesome work such as repair, and improving work efficiency.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, a wheel cylinder 4 is fixed on the bucking plate 2, and a pair of pistons 6 are fitted into the wheel cylinder 4 in a liquid-tight and slidable manner as shown in FIG. There is.
The piston 6 consists of a main body and an insert member 8 press-fitted into the main body, and the head of the insert member 8 is formed with an engagement groove 9 having a rectangular cross section. A boot 10 is attached between the insert member 8 and the wheel cylinder 4 to prevent foreign matter from entering. A pair of shoe assemblies 12 and 14 are arranged on the left and right sides of the wheel cylinder 4, and are urged by a return spring 16 in the direction of approaching each other. It is blocked by a strut device 17 that is stretched between them. One end of the web 18 of these shoe assemblies 12, 14 is engaged with the insert member 8, and the force applied to the piston 6 by hydraulic pressure is transmitted to the web 18 via the insert member 8. web 18
A rim 20 is attached to the outside of the rim 20, and the rim 2
A lining 22 is attached to the outside of 0.

The other end of the web 18 is brought into contact with the anchor block 26 by the biasing force of the retainer spring 24, and a circular engagement hole 28 is formed near the end. The engagement hole 28 is connected to the shoe assembly 1.
2 and 14 from moving beyond what is necessary for their function, and the size is also the minimum necessary. The engagement hole 28 has a third
As shown most clearly in FIGS. 3 and 4, the distal end of the engaging piece 32 extending from the anchor bracket 30 and having its distal end bent at right angles to the web 18 is positioned approximately at the center. It is being inserted. Anchor bracket 30 is located on the back side of anchor block 26 and is fixed to backing plate 2 by rivets 36 together with anchor plate 34 on the front side.

In the drum brake configured as described above, when hydraulic pressure is applied to the wheel cylinder 4, the piston 6 moves the shoe assemblies 12, 1.
4 is pressed against the inner peripheral surface of a brake drum (not shown), and the rotation of the brake drum is suppressed by solid friction between the lining 22 and the brake drum. In this case, the shoe assembly 12,
The movement of 14 is the engagement piece 3 that is fitted into the engagement hole 28.
It is not prevented by 2. Furthermore, as the lining 22 wears down due to repeated braking, the shoe assemblies 12 and 14 move, but this movement is not hindered by the engagement piece 32.

However, when the drum brake assembly was being transported or assembled into a vehicle, it received a strong impact from falling, etc., and the drum brake assembly 12, 1
When 4 moves on bucking plate 2,
This movement is restricted within the radius of the engagement hole 28, and will not separate from the wheel cylinder piston 6 or get between the wheel cylinder piston 6 and the wheel cylinder 4, thereby damaging the boot 10, the wheel cylinder 4, etc. .

Furthermore, the engagement piece 32 that is loosely fitted into the center of the engagement hole 28 is made by deforming and extending the anchor bracket 30, and does not require a new member to be attached during assembly work, and is completely different from the conventional one. It is no different from the work process.

Next, another embodiment of the present invention will be described based on FIG.

The embodiment shown in FIG.
2 is changed to an anchor plate 34 fixed to the front surface of the anchor block 26.
As in the previous embodiment, the engagement piece 32 is extended from the anchor plate 34 so that the tip end is perpendicular to the web 18, and the assembly work is no different from the conventional one. Furthermore, the engagement hole 28 formed on the web 18 side is square, unlike the previous embodiment.

Additionally, the engaging piece 32 may be manufactured separately from the anchor bracket 30 or the anchor plate 34, and later integrated therewith by spot welding or the like.

As explained above, the present invention restricts the movement of the shoe assembly within the functionally necessary range, and the shape and size of the engagement hole and engagement piece formed for this purpose are determined by the shape and size of each drum. Various modifications may be made depending on the function of the brake and ease of processing, and the present invention is not limited to the embodiments described in detail above.

[Brief explanation of the drawing]

Fig. 1 is a front view of a drum brake assembly which is an embodiment of the present invention, Fig. 2 is a detailed sectional view of section A in Fig. 1, Fig. 3 is a BB sectional view in Fig. 1, 4 is a perspective view taken from the direction of arrow C in FIG. 1, and FIG. 5 is a perspective view of another embodiment. 2...Bucking plate, 4...Wheel cylinder, 6...Piston, 9...Engagement groove, 12,
14...Show assembly, 18...Web,
26...Anchor block, 28...Engagement hole, 30
...Anchor bracket, 32...Engagement piece, 34...
...anchor plate.

Claims (1)

[Scope of utility model registration request] In a shoe floating type drum brake, an engagement hole is formed in the vicinity of the end of the web portion of the shoe assembly that comes into contact with the anchor block, and a plate-shaped member is fixed to the front or back surface of the anchor block. an engaging piece extending from the member, the tip of which is substantially perpendicular to the web portion;
A drum brake characterized in that the radial movement of the shoe assembly is restricted within a certain limit by loosely fitting the tip of the engagement piece into the engagement hole.