JP2001317571A - Dram in disc brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dram in disk brake capable of reducing manufacturing cost and preventing degradation of durability caused by rust on a shoe hold down pin for connecting a brake shoe to a backing plate and its periphery. SOLUTION: In the dram in disc brake 21, the backing plate 23 mounted to a car body side so as to cover an opening part of a dram part 3a of a rotating member 3 includes a backing plate body 25 which is an integrally molded product of a metal plate and an auxiliary plate 27 integrally formed on an inner surface of the backing plate body 25 by welding. The shoe hold down pin 10 for connecting the brake shoe 9 arranged on the backing plate 23 to a side of an inner circumference of the dram part 3a so as to enlarge is attached to the auxiliary plate 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum-in-disk brake in which a disk brake mechanism and a drum brake mechanism are integrated, and more particularly, to a reduction in manufacturing cost of a backing plate constituting the drum brake mechanism. The present invention relates to an improvement for improving durability by improving rustproofness of a shoe hold-down pin for connecting a brake shoe and its surroundings by improving waterproofness.

[0002]

2. Description of the Related Art FIGS. 5 to 8 show a schematic structure of a conventional drum-in-disk brake. As shown in FIG. 6, the drum-in-disc brake 1 integrally includes a cylindrical drum portion 3a with a bottom and a rotor portion 3b projecting radially outward from an opening edge of the drum portion 3a. Rotating member 3 attached to the wheel side in preparation for
And a backing plate 5 mounted on the vehicle body side so as to cover the opening of the drum portion 3a and supporting a brake shoe 9 (see FIG. 8) for pressing the inner peripheral surface of the drum portion 3a. By incorporating a drum brake mechanism in the center of 3, the brake by the drum brake mechanism is performed in addition to the brake by the disc brake mechanism.

As shown in FIG. 6, the backing plate 5 includes a backing plate main body 7 integrally formed of a metal plate in a thin disk shape covering the opening of the drum portion 3a,
An auxiliary plate (dust cover) 8 is formed in a substantially ring shape to cover the surface of the rotor portion 3b exposed on the outer periphery of the backing plate main body 7, and is welded to the outer surface of the backing plate main body 7. As shown in FIG. 8, a shoe hold down pin 10 is attached to the backing plate body 7. The shoe hold-down pin 10 supports the brake shoe 9 of the drum brake mechanism, and is connected to the backing plate 5 so that the brake shoe 9 can be expanded toward the inner peripheral side of the drum portion 3a. The auxiliary plate 8 is provided with a pin cover 8a for covering the penetrating portion of the backing plate main body 7 of the shoe hold-down pin 10 and a notch 8b serving as a mounting space for a caliper (not shown) of the disc brake mechanism. It is equipped with a structure.

Although not shown, the brake shoes 9
The mechanism that expands and presses the inner peripheral surface of the drum portion 3a
A well-known drum brake mechanism may be used. Further, a disk brake mechanism such as a caliper that holds the rotor portion 3b between the friction pads may be an existing known mechanism.

[0005]

However, in the above-described structure of the backing plate 5 during running on rainy weather or during car washing, water that has entered the gap 12 between the pin cover 8a and the backing plate main body 7 causes the water to enter the shoe. There is a problem that rust easily adheres to and around the shoe hold-down pin 10 due to the adhesion to the hold-down pin 10, and the shoe hold-down pin 10 falls off due to corrosion caused by the rust. In order to solve such a problem, it has been considered that the auxiliary plate 8 and the backing plate 5 are integrally formed so that the end of the shoe hold-down pin 10 is not exposed to the outside. This leads to an increase in the size of a molding die, a complex molding structure that cannot be solved by a combination of simple drawing, and a new problem of an increase in the manufacturing cost of the backing plate.

The present invention has been made in view of the above circumstances, and aims to reduce the manufacturing cost of a backing plate constituting a drum brake mechanism, improve waterproofness, and connect a brake shoe to the backing plate. It is an object of the present invention to provide a drum-in-disc brake capable of preventing a reduction in durability due to rust on a down pin and its surroundings.

[0007]

A drum-in-disc brake according to the present invention for achieving the above object has a cylindrical drum portion having a bottom and a flange formed radially outward from an opening edge of the drum portion. A rotating member integrally provided with a protruding rotor portion and attached to the wheel side, and a brake shoe attached to the vehicle body side so as to cover the opening of the drum portion and pressing the inner peripheral surface of the drum portion are supported. In addition to the braking by the disc brake mechanism acting on the rotor portion, the drum backing plate also performs braking by a drum brake mechanism acting on the drum portion.
A backing plate body, which is an integrally molded product of a metal plate,
An auxiliary plate integrated with an inner surface of the backing plate body, and a shoe hold configured to connect the brake shoe disposed on the backing plate to the auxiliary plate so as to be able to expand to an inner peripheral side of the drum portion. A down pin is attached.

According to the above construction, the backing plate has a structure in which the auxiliary plate to which the shoe hold-down pin is attached is integrated with the backing plate main body covering the opening of the drum portion, so that the shoe hold-down pin is formed. The ends of the pins are covered by the backing plate main body and are not exposed to the outside, so that when running on rainy weather or during car washing, water is prevented from entering at or around the ends of the shoe hold-down pins. Therefore, a decrease in rust resistance due to water infiltration of the shoe hold-down pin and its surroundings is prevented, and a decrease in durability due to rust can also be prevented. In addition, the backing plate is composed of two parts, a simple substantially thin dish-shaped backing plate main body and an auxiliary plate that is fixed to the inner surface of the backing plate by welding or the like. Since it is not a product, it is possible to avoid complexity and enlargement of a molding die, and eventually, it is possible to reduce the manufacturing cost of the backing plate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a drum-in-disk brake according to the present invention will be described below in detail with reference to the drawings. FIGS. 1 to 4 show an embodiment of a drum-in-disk brake according to the present invention.
FIG. 2 is a front view of a backing plate of a drum-in-disc brake, FIG. 2 is a sectional view taken along the line II-II of FIG.
1 is a sectional view taken along the line III-III in FIG. 1, and FIG.
FIG. 4 is a sectional view taken along the line IV-IV.

As shown in FIGS. 1 and 2, a drum-in-disc brake 21 of this embodiment has a cylindrical drum portion 3a having a bottom and a flange extending radially outward from an opening edge of the drum portion 3a. Rotating member 3 integrally provided with a rotor portion 3b projecting in a shape and attached to a wheel side (not shown)
And a backing plate 23 that is attached to a vehicle body (not shown) so as to cover the opening of the drum portion 3a and supports the brake shoe 9 (see FIG. 4) that presses the inner peripheral surface of the drum portion 3a. In addition to braking by the disk brake mechanism acting on the rotor section 3b, braking is also performed by the drum brake mechanism acting on the drum section 3a.

The backing plate 23 is shown in FIGS.
As shown in FIG. 2, the backing plate body 25 is an integrally molded product of a metal plate, and the auxiliary plate 27 is integrated with the inner surface of the backing plate body 25 by welding.

As shown in FIGS. 2 and 4, the backing plate body 25 has an inner disk portion 25a covering the opening of the drum portion 3a, and is provided continuously with the outer periphery of the inner disk portion 25a to form the rotor portion 3b. As shown in FIG. 1, the outer disk portion 25b has a notch 25c serving as a mounting space for a caliper constituting a disc brake mechanism. The inner disk portion 25a is drawn and formed so as to be one step lower than the outer disk portion 25b, but the entire backing plate main body 25 is an integrally molded product having a substantially thin plate-like structure. In addition,
As shown in FIG. 1, on the surface of the inner disk portion 25a, ledge portions 29 for providing a ledge surface 29a serving as a sliding surface of the brake shoe 9 are formed in a plurality of protruding positions in the circumferential direction outside the auxiliary plate 27. Have been.

The auxiliary plate 27 has a ring shape and has a sealing flange portion 27 which is formed on an outer peripheral portion thereof and which protrudes into a seal groove 3c formed annularly along the inner periphery of the rotor portion 3b.
a, which is integrated with the backing plate main body 25 by six spot weldings indicated by arrows (a). Then, as shown in FIG.
a on the protruding piece 27b of the auxiliary plate 27 which overhangs
A shoe hold down pin 10 is attached.
The shoe hold-down pin 10 couples the brake shoe 9 of the drum brake mechanism to the inner peripheral side of the drum portion 3a so as to be able to expand.

Although not shown, the mechanism for expanding the brake shoe 9 mounted on the backing plate 23 and pressing it against the inner surface of the drum portion 3a may be a known mechanism as a drum brake mechanism. Also, the rotor portion 3b
A disc brake mechanism such as a caliper for holding the disk by a friction pad may be an existing known mechanism.

The backing plate 23 of the above-described drum-in-disc brake 21 has a structure in which an auxiliary plate 27 for mounting the shoe hold-down pin 10 is welded to the inner surface of a backing plate body 25 that covers the opening of the drum 3a. As shown in FIG. 5, the end of the shoe hold-down pin 10 is covered with the backing plate body 25 and is not exposed to the outside. And there is little risk of flooding around it. Therefore, it is possible to prevent a decrease in rust resistance due to water infiltration of the shoe hold-down pin 10 and its surroundings, thereby preventing a decrease in durability due to rust.

The backing plate 23 is composed of two parts, a backing plate body 25 having a simple thin plate shape and an auxiliary plate 27 welded to the inner surface thereof. Therefore, it is possible to avoid the complexity and enlargement of the molding die, and eventually, it is possible to reduce the manufacturing cost of the backing plate 23.

[0017]

According to the drum-in-disc brake of the present invention, the backing plate has a structure in which the auxiliary plate for attaching the shoe hold-down pin is welded to the inner surface of the backing plate body that covers the opening of the drum.
Since the end of the shoe hold-down pin is covered by the backing plate body and is not exposed to the outside, there is a possibility that the shoe hold-down pin will be exposed to water at the end of the shoe hold-down pin and its surroundings during running on rainy weather or during car washing. Few. Therefore, it is possible to prevent a decrease in the rust prevention property of the shoe hold-down pin and its surroundings, thereby preventing a decrease in durability due to rust. Further, the backing plate is composed of two parts, a simple substantially thin dish-shaped backing plate main body and an auxiliary plate welded to the inner surface thereof, and is not an integrally molded product having a complicated structure. The complexity and size of the mold can be avoided, and eventually, the manufacturing cost of the backing plate can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a backing plate of one embodiment of a drum-in-disc brake according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1;

FIG. 5 is a front view of a backing plate of a conventional drum-in-disc brake.

6 is a sectional view taken along the line VI-VI of FIG. 5;

7 is a sectional view taken along the line VII-VII in FIG.

8 is a sectional view taken along the line VIII-VIII in FIG.

[Explanation of symbols]

 Reference Signs List 3 rotating member 3a drum part 3b rotor part 3c sealing groove 9 brake shoe 10 shoe hold-down pin 21 drum-in disc brake 23 backing plate 25 backing plate body 25a inner disk part 25b outer disk part 25c notch 27 auxiliary plate 27a sealing flange part 27b protruding piece

Claims (1)

[Claims] A rotating member attached integrally to a wheel side, integrally comprising a cylindrical drum portion having a bottom and a rotor portion projecting radially outward from an opening edge of the drum portion; A backing plate mounted on the vehicle body side so as to cover the opening of the portion, and supporting a brake shoe that presses the inner peripheral surface of the drum portion, in addition to braking by a disc brake mechanism acting on the rotor portion. A drum-in-disc brake that also performs braking by a drum brake mechanism that acts on the drum portion, wherein the backing plate is a backing plate body that is an integrally molded product of a metal plate, and an auxiliary that is integrated with the inner surface of the backing plate body. And the brake shoe disposed on the backing plate on the auxiliary plate. A drum-in-disc brake, wherein a shoe hold-down pin is attached to the inner peripheral side of the drum portion so as to be expandable.