JPS5850121Y2 - Drum brake squeal prevention structure - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a structure intended to prevent squealing when braking is applied to a drum brake.

When considering the cause of the problem of so-called "squeal" during braking, the main cause is that the center of compression of the left and right type 0 brake shoes on the inner peripheral surface of the drum is symmetrical with respect to the center of the drum. It is said that there is.

Therefore, by making a difference in the tension angle of the pair of left and right brake shoes, in other words, by using brake shoes of different shapes, it is possible to prevent squeal by configuring the suppression center so that it is not located on the diameter line of the drum. However, in such a configuration, the left and right brake shoes are not compatible, making the assembly process complicated, and when replacing parts due to lining wear, each brake shoe must be prepared separately. There are disadvantages such as the need to press the button.

From this point of view, the present invention provides a drum brake squeal prevention structure in which the left and right brake knees are used as they are in the same shape, and the suppression center of these brakes is not located on the diameter line of the drum.

The present invention will be explained below based on the embodiments shown in the drawings.
The figure shows an example of a so-called twinplex two-way drum brake. 1 is a backing plate, 2
, 2 are a pair of left and right plate knees supported on the backing plate 1 by supports 3, 3 so as to be able to expand and slide, and linings 4, 4 which are pressed against the inner peripheral surface of the drum (not shown) are 6-type rim 5 fixed to the outer peripheral surface
5, and a web 6.6 fixed to the widthwise center portion of the inner peripheral surface of the rims 5, 5 so as to protrude radially inward along the circumferential direction.
and supports 3, 3 for the backing grate 1.
are fitted into elongated holes 7, 7 formed in the web 6.6.

Reference numerals 8 and 8 are return springs that apply spring force radially inward to the brake shoes 2, 2, and are connected to pins 9.9 fixed to the backing plate 1 and webs 6.6 of the brake shoes 2, 2. It is stretched between the provided pins 10.10.

Reference numerals 11 and 12 designate wheel cylinders fixed to the backing plate 1 so as to be located between the inner ends of the pair of brake shoes 2, 2, each housing a pair of pistons.

One end of the brake shoe 2.2 engages with two sides 11a or 12a of the -44 piston, and the other end engages with the other piston 11b or 12b.

When the drum 75 is rotated clockwise due to the operation of the wheel cylinder, the piston 11a or 12a becomes part of the anchor, and the pair of brake shoes 2, 2 are expanded against the return springs 8, 8. .

The feature of the present invention is that in addition to the above configuration, one of the wheel cylinders 11 has a pair of pistons 11a.

The corresponding deviation of 11b is that the length L21t'z between the engagement part with the key shoe 2.2 is different from the length Ll in the case of the other wheel cylinder 12 (L2>Ll), and this is To explain in terms of the angle from the diameter line a of the drum, in this example, the wheel cylinder 1 located at the upper side of the figure
Since brake shoe 1 is longer, the compression center of the left and right brake shoes 2.2 is not located on the diameter line of the drum even though the pair of brake shoes 2.2 have the same shape and the tension angle θ2=04. This makes it possible to prevent squeal while maintaining brake shoe compatibility compared to conventional drum brakes.

The present invention can also be applied to twin brex one-way drum brakes.

As mentioned above, the drum brake squeal prevention structure according to the present invention is able to prevent squeal by simple improvement compared to the conventional structure, and its practical benefits are extremely large.

[Brief explanation of drawings]

The figure is a front view showing an embodiment of the drum brake according to the present invention. 1...Backing plate, 2...Brake shoe 3...Support, 4...
Lining, 5... Rim, 6... Web, 1... Long hole, 8... Return shibane, 9
...Pin, 10...Pin, 11.12
...Wheel cylinder, 11a, 12a, 1
1b, 12b...Piston.

Claims (1)

[Scope of utility model registration request] In a drum brake in which a pair of wheel cylinders each having an expansion mechanism are disposed between the opposite sides of a pair of left and right brake shoes forming a type 6, the pair of brake shoes are formed in the same shape, and the pair of brake shoes are formed in the same shape. A drum brake characterized in that the length between the engaging part with the pair of brake shoes on one of the wheel cylinders is different from the length between the engaging part with the pair of brake shoes on the other wheel cylinder. Anti-squeal structure.