JP2016142400A - Back plate for vehicular drum brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a back plate for a vehicular drum brake in which water droplet or the like can be prevented from immersing into an inside of a drum brake.SOLUTION: A dust shield 2b provided with an annular edge part 2d protruded toward an annular groove 7a arranged at an outer peripheral part of a brake drum 7 and freely fitted into the annular groove 7a is fixed to an outer peripheral side of an inside part of a back-plate main body 2a for storing in an expandable or shrinkable manner a brake shoe slidably contacted with the brake drum 7. The annular edge part 2d is formed while its protruding edge 2e is gradually inclined at an outer peripheral side of the brake drum, freely fitted into the annular groove 7a in a labyrinth seal manner and at the same time a water passage pocket 15 is formed between a base end side of the annular edge part 2d and the back-plate main body 2a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a back plate of a drum brake for a vehicle used in a traveling vehicle such as an automobile or a motorcycle, and more specifically, an annular groove provided in an outer peripheral portion of a brake drum in a back plate body that accommodates a brake shoe in an expandable / contractible manner. The present invention relates to a back plate of a vehicle drum brake to which a dust shield having an annular edge portion that is loosely fitted to the vehicle is attached.

  2. Description of the Related Art Conventionally, in a vehicle drum brake, a dust shield having an annular edge portion loosely fitted in an annular groove provided in an outer peripheral portion of a brake drum is attached to an outer peripheral portion of a back plate body that accommodates a brake shoe in a freely expandable and contractible manner Known to prevent rainwater and dust from entering the brake. The dust shield is provided integrally with a ledge portion that guides the brake shoe so that the brake shoe can be expanded and contracted, and has an annular edge projecting perpendicularly from the ledge portion toward the annular groove of the brake drum (for example, Patent Document 1). (See, for example, Patent Document 2) In some cases, an annular edge protrudes perpendicularly from the dust shield body welded to the inner periphery of the back plate body toward the annular groove.

Utility model registration No. 3141969 JP 2002-295544 A

  However, in the above-mentioned Patent Document 1 and Patent Document 2, since the annular edge portion of the dust shield protrudes at a right angle with respect to the back plate main body, water droplets such as rain water entering from the outside are caused by the annular edge portion. There was a risk that the tip part would fall into the annular groove of the brake drum and enter the drum brake along the wall surface of the brake drum.

  Accordingly, an object of the present invention is to provide a vehicular drum brake back plate capable of preventing water droplets such as rainwater from entering the drum brake.

  In order to achieve the above object, the back plate of the drum brake for a vehicle according to the present invention is provided on the outer periphery of the brake plate on the inner peripheral side of the back plate main body that accommodates the brake shoe slidingly contacting the brake drum. In a back plate of a drum brake for a vehicle mounted with a dust shield provided with an annular edge that protrudes toward the annular groove and is loosely fitted in the annular groove, the annular edge is braked on the protruding end side more than the base end side. A water channel pocket is formed between the back plate main body and the base end side of the annular edge portion to store water droplets that have entered between the back plate and the brake drum. It is characterized by.

  Further, it is preferable that the annular edge portion is formed so that the protruding end side is gradually inclined toward the outer peripheral side of the brake drum.

  According to the back plate of the drum brake for a vehicle of the present invention, water droplets that have entered from the gap between the back plate body and the brake drum are received by the annular edge of the dust shield, and are also the base end side of the annular edge. Since it is guided to the plate body side and accommodated in the water channel pocket, water drops do not enter the drum brake.

  Further, by forming the projecting end side of the annular edge portion to be gradually inclined toward the outer peripheral side of the brake drum, it is possible to prevent water droplets from entering the drum brake by simple processing.

It is principal part sectional drawing of the back plate which shows the 1st form example of this invention. It is II-II sectional drawing of FIG. It is a front view of the drum brake for vehicles which shows the 1st example of the present invention. It is principal part sectional drawing of the backplate which shows the 2nd example of a form of this invention.

  FIGS. 1 to 3 are views showing a first embodiment of the back plate of the vehicle drum brake of the present invention. The vehicle drum brake 1 of this embodiment is provided on the inner surface of the back plate 2 fixed to the vehicle body. A pair of brake shoes 3, 4 formed in an arcuate shape is disposed, and one end of each brake shoe 3, 4 is in contact with the piston of the wheel cylinder 5 and the other end is in contact with the anchor 6.

  In the vehicle drum brake 1, the brake shoes 3, 4 are expanded outward in the radial direction of the back plate 2, and the linings 3 a, 4 a provided on the outer periphery of the brake shoes 3, 4 are used as the brake drum 7. One of the brake shoes 3 is supported by one end of a parking lever 8 on a support shaft, and the other end of the parking lever 8 is provided with a parking lever 8. A brake cable 9 for towing the vehicle is connected.

  The brake shoes 3 and 4 are elastically held on the back plate 2 by shoe hold pins 10 and shoe hold springs 11, respectively. A shoe return spring 12 and a connecting spring 13 are stretched between the brake shoes 3 and 4 on the inner side of the wheel cylinder 5 and the outer side of the anchor 6, respectively. The brake is automatically biased in the direction of diameter reduction, and an automatic braking gap adjusting device 14 is disposed on the center side of the back plate of the shoe return spring 12 on the wheel cylinder side.

  The brake drum 7 is formed in a bottomed cylindrical shape, and is braked when the brake shoes 3 and 4 are expanded and the linings 3a and 4a are in sliding contact with the inner peripheral portion. An annular groove 7 a is formed on the outer surface of the brake drum 7 facing the back plate 2.

  The back plate 2 is a back plate main body 2a formed by pressing one steel plate, and similarly a dust shield formed by pressing one steel plate and attached to the inner peripheral side of the back plate main body 2a. 2b. The back plate body 2a is formed in a disc shape having a hole for inserting a knuckle and a hub unit (both not shown) in the center, and a drum brake including the brake shoes 3 and 4 and the anchor 6 therein. These various structural members are arranged and attached to the vehicle body by bolting the inner peripheral side to a knuckle.

  The dust shield 2b is provided on the inner peripheral side and is attached to the back plate body 2a by spot welding or the like, and an annular edge provided on the outer peripheral side and protruding toward the annular groove 7a side of the brake drum 7 2d. The annular edge 2d is formed so that the protruding end 2e side is gradually inclined toward the outer periphery of the brake drum, enters the annular groove 7a, and is loosely fitted into the annular groove 7a in a labyrinth manner, and the annular edge 2d. A water channel pocket 15 is formed between the base end side of this and the back plate body 2a.

  As shown in FIG. 1, the vehicle drum brake 1 of the present embodiment formed as described above has a water droplet W <b> 1 such as rainwater entering the inside through a gap between the back plate body 2 a and the brake drum 7. The invading water droplet W1 is received by the annular edge 2d, guided to the proximal end side of the annular edge 2d along the inclination of the annular edge 2d, and accommodated in the water channel pocket 15. Thereby, it is possible to prevent the water droplets W1 from entering the interior of the vehicle drum brake 1, and there is no possibility that rust is generated on various components inside the drum brake. Further, the annular edge 2d can be formed by simple processing, and there is no risk of increasing costs.

  FIG. 4 shows a second embodiment of the present invention. Components that are the same as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The annular edge 2g of the dust shield 2f of the present embodiment includes a first right angle portion 2h protruding perpendicularly in the direction of the annular groove 7a from the mounting portion 2c, and an outer peripheral side of the brake drum 7 from the tip end portion of the first right angle portion 2h. And a second right angle portion 2i projecting at right angles to the front end of the first right angle portion 2h and the second right angle portion 2i enter the annular groove 7a and loosely fit into the annular groove 7a in a labyrinth form. . In the present embodiment, the water channel pocket 16 is formed by the first right-angle portion 2h, the second right-angle portion 2i, and the back plate body 2a, so that the volume of the water channel pocket 16 can be increased.

  The present invention is not limited to the application to the leading / trailing type drum brake as in the above-described embodiments, and the structure of the drum brake is arbitrary. Further, the present invention can be applied to a drum-in disc brake in which a disc brake is provided on the outer peripheral side of the drum-in disc rotor and the drum brake is disposed on the inner peripheral side.

DESCRIPTION OF SYMBOLS 1 ... Drum brake for vehicles, 2 ... Back plate, 2a ... Back plate main body, 2b ... Dust shield, 2c ... Mounting part, 2d ... Ring edge, 2e ... Projection end, 2f ... Dust shield, 2g ... Ring edge, 2h ... 1st linear part, 2i ... 2nd linear part, 3, 4 ... Brake shoe, 3a, 4a ... Lining, 5 ... Wheel cylinder, 6 ... Anchor, 7 ... Brake drum, 7a ... Annular groove, 8 ... Parking lever , 9 ... Brake cable, 10 ... Shoe hold pin, 11 ... Shoe hold spring, 12 ... Shoe return spring, 13 ... Connection spring, 14 ... Automatic brake clearance adjusting device, 15, 16 ... Water pocket

Claims (2)

  An annular edge that protrudes toward the annular groove provided in the outer peripheral portion of the brake drum and is loosely fitted in the annular groove is formed on the inner outer peripheral side of the back plate main body that accommodates the brake shoe slidably contacting the brake drum. In the vehicular drum brake backplate provided with the dust shield, the annular edge is positioned on the outer peripheral side of the brake drum from the base end side of the projecting end side, and the base of the back plate body and the annular edge portion is provided. A back plate of a drum brake for a vehicle, wherein a water channel pocket is formed between the end side to store water droplets that have entered between the back plate and the brake drum.   The back plate of a drum brake for a vehicle according to claim 1, wherein the annular edge portion is formed so that the protruding end side is gradually inclined toward the outer periphery side of the brake drum.

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