JPH026274Y2 - - Google Patents

Description

[Detailed explanation of the idea] <Industrial application field> The present invention relates to a drum brake.

<Prior art> Generally, in a drum brake, in order to determine the gap between the brake drum and the brake shoe, the edge of the brake shoe comes into contact with a regulating device (for example, a wheel cylinder, etc.) and the return position of the brake shoe is adjusted. regulated.

The end portion of the brake shoe is fitted into a groove provided in the regulating device to restrict movement of the brake shoe in the width direction.

<Problems to be Solved by the Present Invention> The conventional drum brake described above has the following problems.

(b) When attaching or removing the brake shoe, normally grasp the brake shoe with your hand, spread it outward against the force of the shoe return spring, and insert and remove the end of the brake shoe from the groove of the regulating device. There must be.

Therefore, when the shoe return spring has a large spring force, or when the drum brake is operated while attached to the pedestal, it becomes very difficult to insert and remove the end of the brake shoe from the groove.

(b) Another method for attaching and detaching the brake shoe is to use a rod-shaped tool such as a screwdriver.

This method involves inserting a rod-shaped tool between the end of the brake shoe and the opposing surface of the regulating device, and then using this tool as a lever to push the brake shoe outward. It is.

However, according to this method, since the facing surfaces of the brake shoe and the regulating device that the bar-shaped tool comes into contact with are smooth, the tool tends to slip and it is difficult to attach and detach the brake shoe.

Moreover, if the tool slips, there is a high risk of injury to the worker.

<Purpose of the present invention> The present invention was made to solve the above-mentioned problems, and its purpose is to provide a drum brake that allows the brake shoe to be attached and detached safely and easily. do.

<Technical means for solving the problem> The present invention provides a recess in the end of the brake shoe, the regulating device, or both, in which a rod-shaped tool can be engaged without slipping. The above problems have been solved.

<Configuration of the present invention> The drum brake according to the present invention will be described below with reference to the drawings.

<A> Overall description of drum brake In this embodiment, a two-leading type drum brake in which a wheel cylinder is provided between the upper and lower sides of the brake shoe will be explained as an example.

Although the lower half of this drum brake drum is shown in FIG. 1, the upper half has a similar structure and will not be described here.

<B> Structure of the lower half of the drum brake In Fig. 1, numerals 1 and 2 are brake shoes mounted so as to be expandable and retractable.

11 and 21 are linings that are in direct contact with the brake drum, and 12 and 22 are linings 11 and 22 that are in direct contact with the brake drum.
21 is attached to the rim, and 13 and 23 are the rims 1
2 and 22 are integral webs.

Both brake shoes 1 and 2 have a protruding body 31 protruding from the back plate 3 on one side of the rims 12 and 22.
movably mounted on the top.

A wheel cylinder 6 is disposed between the lower portions of both brake shoes 1 and 2, and is fixed on the back plate 3 with bolts 5.

Furthermore, the web 1 of both brake shoes 1 and 2
A shoe return spring 4 is stretched between 3 and 23.

<C> Brake shoe expansion/contraction structure In the drum brake of this embodiment, the right brake shoe 1 is pushed out by the wheel cylinder 6 disposed at the bottom of the drum brake, and the wheel cylinder (not shown) disposed at the top of the drum brake is expanded. It has a structure in which a cylinder pushes out the brake shoe 2 on the left side of the drawing.

<D> Engagement state of brake shoe and wheel cylinder [Wheel cylinder] A blind hole 62 is formed in one side of the cylinder body 61, and the piston 7 is slidably housed inside.

This structure allows the piston 7 to slide by introducing brake oil through a hole 63 provided in the blind hole 62 and discharging it.

Furthermore, a cup 71 is provided on the outer periphery of the base end of the piston 7.
is installed to ensure a liquid-tight condition.

A flange 72 at the tip of the piston 7 is provided with teeth around the entire circumference in order to transmit rotational force to the piston 7.

Further, inside the piston 7, an adjustment bolt 8 is screwed and housed in a hole formed at the axial center position.

[Brake shoe fitted state]

A groove 81 is formed in the distal end surface of the adjusting bolt 8, and the end of the web 13 of the brake shoe 1 to be pushed apart is fitted into the groove 81.

Further, a groove 6 is provided on the other end side of the cylinder body 61.
4 is recessed, and the end of the web 23 of one brake shoe 2 is fitted into this groove 64.

Further, both brake shoes 1 and 2 are operated by a shoe return spring 4 to prevent the web 1 of the brake shoes 1 and 2 from moving.
Since the ends of the grooves 3 and 23 are in contact with the bottom surfaces of the respective grooves 81 and 64, their return positions are restricted.

<E> Creation of Engagement Recess Groove One of the features of the present invention is that a depression (engagement recess D) is provided at a position where a rod-shaped tool does not slip when attaching and detaching the brake shoes 1 and 2.

Below, some examples of recessed configurations are shown.

(1) Example of an engagement recess formed on the rim [Structure] As shown on the right side of Figs. 1 and 2, an engagement recess D, which is a recess, is formed in the rim 12 of the brake shoe 1. do.

[Show attachment/detachment operation]

When removing brake shoe 1, remove rim 1.
Insert the rod-shaped tool 9 shown by the dashed line into the engagement recess D of No. 2, put the tip of the tool 9 against the end face of the adjuster bolt 8, and tighten the lever to release the web 13.
can be easily extracted from the groove 81.

This is because the rod-shaped tool 9 is engaged with the engagement recess D, and it is possible to reliably prevent the tool 9 from sliding sideways during work.

When assembling the brake shoe 1, the tool 9 is inserted obliquely from the direction of the flange 72 of the piston 7, or a dogleg tool is used.

(2) An example in which engaging recesses D are provided in the facing surfaces of the web and the body, respectively [Structure] As shown on the left side of Figs. 1 and 2, the web 23 of the brake shoe 2 and the cylinder body 61 are respectively engaged. The recessed portion D can be provided in a recessed manner.

Both engagement recesses D are formed in the direction of the shaft that supports the drum brake (the direction of the short side of the web).

[Show attachment/detachment operation]

When removing the brake shoe 1, insert the bar-shaped tool 9 into the engagement recess D formed in the web 23 and the cylinder body 61 and tighten the lever, thereby removing the web 2 while preventing the tool 9 from skidding.
3 can be easily removed from the groove 64 of the cylinder body 61.

(3) Other examples of recessed engagement recesses If it is difficult to operate the tool 9 in front of the drum brake, the rim 11 of the brake shoe 1
It is also possible to provide the engaging recess D parallel to the surface of the back plate 3 as in the example shown in FIG.

Further, it is also possible to provide an engaging recess in only one of the web 23 and the cylinder body 61.

<Other Examples> In addition to the above-mentioned two-leading type drum brake, there are also known ones in which an adjuster for adjusting the gap between the brake drum and the lining is mounted on the opposite side of the cylinder body from the piston side, and a wheel cylinder. Instead, it can be widely adopted as a type in which an adjuster device capable of regulating the return position of both brake shoes is arranged, and a shoe expansion actuating device (not shown) is arranged between the upper ends of the brake shoes.

<Effects> Since the present invention is as explained above, the following effects can be expected.

(a) Tool slippage can be reliably prevented by simply forming a simple depression in the end of the brake shoe or the regulating device that faces this end.

Therefore, it is possible to safely attach and detach the brake shoe.
And it can be done easily.

(b) It is sufficient to simply form a recess without adding or forming any new parts.

Therefore, processing is easy.

(c) It can be used in various types of drum brakes, so it has wide versatility.

[Brief explanation of the drawing]

Figure 1: Front view of the lower half of the brake drum, Figure 2: Bottom view thereof.

Claims (1)

[Scope of Claim for Utility Model Registration] In a drum brake in which the end of the brake shoe is fitted into a groove of a regulating device that regulates the return position of the brake shoe, A drum brake characterized by having a concave portion on one or both of the opposing surfaces that can be engaged with a rod-shaped tool.