JPH066297Y2 - Drum brake for vehicles with parking brake - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a vehicle drum brake equipped with a parking brake, and more particularly to a smooth operation of the parking brake and a detent for a shoe hold spring that holds the brake shoe. The drum brake structure is intended.

[Conventional technology]

Conventional drum brakes with parking brakes
A brake shoe that expands by hydraulic pressure of a wheel cylinder is elastically held by a back plate by a shoe hold down pin and a plate-shaped shoe hold spring, and on the expansion side of the brake shoe, a side surface of the back plate of the web of the shoe is provided. One end of the parking lever arranged in parallel with is pivotally supported by a lever pin, and when the brake cable connected to the other end of the parking lever is pulled, the parking lever rotates about the lever pin as a fulcrum, As a result of the reaction, the brake shoe expands, and the lining of the shoe slides against the inner peripheral surface of the brake drum to perform the braking action.

Since the parking lever is pivotally supported on the web side of the brake shoe as described above, the traction force of the brake cable is transmitted to the web of the brake shoe by an unbalanced load, which causes a loss of rotational power and rattling of the parking lever. This is the reason for this, and for this reason, for example, Japanese Utility Model Laid-Open No. 50-113781.
As disclosed in Japanese Patent Laid-Open Publication No. 2005-163, there is known a structure in which a parking lever is formed so as to sandwich both sides of a brake shoe, and a lever pin is supported by both ends to solve these problems.

[Problems to be solved by the invention]

However, in the above-mentioned one, the weight of the brake lever is increased to make the entire brake heavy, the traction resistance of the brake cable is increased, and the cost is inevitably increased due to the increase in the material.

Therefore, the present invention has an object to provide a vehicle drum brake which is capable of preventing a loss of rotational power and rattling of a parking lever and also preventing a shoe hold spring from rotating while reducing weight and cost. There is.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention elastically holds a brake shoe on a back plate with a shoe hold down pin and a shoe hold spring, and the brake shoe is arranged on the expansion side of the brake shoe in parallel with the web side surface of the brake shoe. In a vehicle drum brake with a parking lever pivotally supported, a cut is provided in the web, and the cut piece is bent and arranged parallel to the web with a gap toward the parking lever side, and the parking lever is provided in the gap. Through the web, the parking lever is held by the web and the cut piece, and a tongue piece is formed on the shoe hold spring, and the tongue piece is locked in the cutout hole of the web in which the cut piece is cut out. It is characterized in that the hold spring is stopped.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

The drum brake 1 includes a pair of brake shoes 2 and 3,
The back plate 4 fixed to the vehicle body is elastically supported by the shoe hold down pin 5 and the shoe hold spring 6, respectively, and the fulcrum side end portions 2b and 3b on one side of the arcuate webs 2a and 3a are supported by the anchor 7. At the same time, the expansion side end portions 2c and 3c on the other side are disposed in contact with the pistons 9 and 9 of the wheel cylinder 8 that hydraulically expands the shoes 2 and 3, respectively.

The shoe hold down pin 5 has its base end 5a locked to the back surface of the back plate 4, and is connected to the webs 2a and 3a.
A shoe hold spring 6 formed by bending a spring plate into a U-shape is contracted between the web 2a and 3a and the engaging portion 5b at the tip protruding to the side opposite to the back plate. The brake shoes 2 and 3 are held.

Each of the brake shoes 2 and 3 includes the webs 2a and 3a,
Rims 2d, which are arranged to cross the outer edges of the webs 2a, 3a,
3d and the linings 10 and 10 attached to the outer peripheral surfaces of the rims 2d and 3d. The brake shoes 2 and 3 are contracted in the vicinity of the anchor 7 and the wheel cylinder 8 between the webs 2a and 3a. Even when the return springs 11 and 12 for urging the linings 10 are stretched, and the linings 10 and 10 are worn near the return spring 12 on the expansion side, a gap with a brake drum (not shown) is expanded. An automatic braking gap adjusting device 13 that automatically compensates for this and maintains a constant braking gap is provided.

The arrow A in FIG. 1 indicates the direction of rotation of the front wheels and the brake drum that rotates integrally with the front wheels when the vehicle is moving forward. The brake shoe 3 on the trailing side is provided on the back plate 4 side.
A parking lever 14 is provided in parallel with the web 3a, and one end 14a of the lever 14 is pivotally supported by a lever pin 15 on the expansion side end 3c of the web 3a and the other end 14b.
The towing brake cable 16 is connected to the
The substantially middle portion is held by the web 3a and the cut piece 17.

The cut-out piece 17 is formed in the vicinity of the shoe hold down pin 5 of the web 3a by leaving a side on the outer edge side in a U-shaped cut-out, and further, toward the parking lever 14 side, a gap C is formed between the web 3a and the parking lever 14. The parking lever 14 is inserted in the gap C and is held by the web 3a and the cut piece 17 on both side surfaces in the middle thereof.

Further, the shoe hold spring 6 on the side of the brake shoe 3 is rotated around the shoe hold down pin 5 as a fulcrum by the vibration during traveling or spreading by utilizing the cutout hole 18 of the web 3a obtained by cutting out the cutout piece 17. , The tongue 6a is bent and formed at the end on the web 3a side so that the tongue 6a does not come into contact with the rim 3d, and the tongue 6a is cut out.
The shoe hold spring 6 is stopped by rotating the shoe hold spring 6.

The present embodiment is configured as described above, and the parking lever 14 is pivotally supported on one side portion of the break cue 3, but the intermediate both side surfaces are held by the web 3a and the notch 17, so that the lever pin 14 is held. Parking lever 14 pivotally supported by 15
The backlash is suppressed, the unbalanced load is suppressed, the pulling of the brake cable 16 and the power transmission to the web 3a can be performed smoothly, and the transmission loss of the rotational power can be reduced.

Moreover, since it is not necessary to reshape the web 3a of the brake shoe 3 by cutting and bending the web 3a as in the conventional case, the cost is low and the weight of the brake cable is not increased. Excellent in towing.

Furthermore, since the cutout hole 18 of the cutout piece 17 is used to prevent the shoe hold spring 6 from rotating and to prevent the generation of abnormal noise, a high practical effect can be obtained.

[Effect of device]

As described above, according to the present invention, a notch is provided in the web of the brake shoe on the parking lever side, and the notch piece is bent and arranged parallel to the web with a gap toward the parking lever side, and the parking lever is placed in the gap. Through the web, the web and the notch piece hold the parking lever, and a tongue piece is formed on the shoe hold spring that holds the brake shoe, and the tongue piece engages with the cutout hole of the web obtained by cutting out the notch piece. Since it stopped and stopped the shoe hold spring, the drum brake with the barking brake that suppressed the rattling of the parking lever and suppressed the unbalanced load and reduced the transmission loss of the turning power by only simple processing, It can be provided in a lightweight and low cost.

Further, since the cutout hole is used to prevent the shoe hold spring from rotating, it is highly economical and practical.

[Brief description of drawings]

1 shows an embodiment of the present invention, FIG. 1 is a front view of a drum brake, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a sectional view taken along line III-III of FIG. . 1 ... Drum brake, 2, 3 ... Brake shoe, 2a,
3a ... Web, 2b, 3b ... End part on fulcrum side, 2c, 3c ...
Expansion side end portions, 2d, 3d ... rim, 4 ... back plate,
5 ... shoe hold down pin, 6 ... shoe hold spring, 10 ... lining, 14 ... parking lever, 14a ... one end, 14b ... other end, 15 ... lever pin,
16 ... Brake cable, 17 ... Cutout piece, 18 ... Cutout hole, A ... Rotation direction of wheel and brake drum when the vehicle moves forward, C ... Gap between web 3a and cutout piece 17

Claims (1)

[Scope of utility model registration request] 1. A brake shoe is elastically supported on a back plate by a shoe hold down pin and a shoe hold spring, and a parking lever arranged in parallel with a web side surface of the brake shoe is pivotally supported on the expansion side of the brake shoe. In a vehicle drum brake, a cut is provided in the web, and the cut piece is bent and arranged parallel to the web with a gap on the parking lever side, and the parking lever is inserted into the gap to form a web. Holding the parking lever with the cutout piece, forming a tongue piece on the shoe hold spring, engaging the tongue piece with the cutout hole of the web obtained by cutting out the cutout piece, and stopping the shoehold spring from rotating. A drum brake for vehicles with a parking brake.