JP2554095Y2 - Integrated backing plate for drum brake - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backing plate for a drum brake used for braking an automobile or the like.

[0002]

2. Description of the Related Art Drum brakes are widely used as automobile brakes. The brake is a device that brakes the wheels by pressing a lining of a brake shoe against an inner peripheral surface of a drum that is coupled to the wheels and rotates together with the wheels, and brakes the drums by a frictional force generated between the two. It is configured as illustrated in FIG. FIG. 7 is a front view of a backing plate to which components are attached.

In FIG. 7, reference numeral 1 denotes a backing plate made of a steel plate, 2 denotes a drum which overlaps the backing plate 1 with the folded edge 1a of the backing plate sandwiched between grooves on the peripheral end face, 3
Is a shaft hole for passing the axle, 4 is a bolt insertion hole for fixing the backing plate 1 to the vehicle body, 5 is a hole for fitting and fixing the base of the wheel cylinder 6, and 7 is loosened to the backing plate by the hold-down device 8. With the brake shoe attached, one end 7a is engaged with the anchor 9,
The other end 7b is engaged with the piston rod of the wheel cylinder. The anchor 9 is fixed to the backing plate by the stud 9a. 10 and 11 are brake spring return springs, and 12 is a parking brake lever. One end is pivotally connected to one brake shoe 7 by a shaft 13 and the other end is connected to a cable (not shown) guided by a cable guide 14. Is done. Reference numeral 15 denotes a hole through which a cable passes, and reference numeral 16 denotes a dust shield welded to a backing plate to prevent dust and water from entering the drum.

As described above, a large number of parts are mounted on the backing plate, and welding, caulking, etc. are required for mounting the parts, and irregularities are formed in order to properly arrange these parts. In addition, the manufacturing process becomes complicated.

[0005] Further, since the steel plate is formed to have a uniform thickness, it is not possible to increase the thickness of only the portion that requires strength. Inevitably, the weight of the plate increases.

In order to reduce the weight of the backing plate,
A method of press-forming an aluminum plate and joining it by welding or the like is also conceivable, but this method is not advantageous because it significantly increases the cost.

In order to avoid the above drawbacks and to reduce the weight, one of the present inventors proposed an aluminum-based composite material reinforced with an aluminum alloy or ceramic particles or fibers, or reinforced with silicon carbide (SiC). (In this specification, these materials are simply referred to as aluminum material.) An integral backing manufactured by a pressure casting method (a molten metal forging method or a die casting method) by making only necessary parts thick and unnecessary parts thin. The inventors invented a backing plate in which an iron piece is embedded in a plate and, if necessary, a portion which is easily worn or damaged, and filed a patent application (Japanese Patent Application No. 3-108101).

FIGS. 8 and 9 show a backing plate of the invention according to the above-mentioned application in which a cable guide is formed in the same body and other parts are removed by a pressure casting method of an aluminum material. FIG. 8 is a front view and FIG. FIG. 9 is a sectional view taken along line AA of FIG. 8.

In the backing plate made of aluminum, the brake shoe ledge surface (the flat portion of the backing plate on which the brake shoe 7 slides) and the side surface portion of the anchor 9 with which the brake shoe end 7a abuts have hardness and resistance. Although abrasion is required, these properties are not sufficient with only aluminum material. Therefore, in the above-mentioned invention, reinforcing pieces such as iron pieces are embedded in these portions to reinforce them.

FIG. 8 shows hatched portions of a backing plate made of an aluminum material, where reinforcement is desirable.

[0011]

[Problems to be solved by the invention] In order to embed reinforcing pieces on the brake shoe ledge surface or the anchor side surface at the time of pressure casting not only of aluminum material but also of light metal, light alloy or a composite material thereof, it is necessary to reinforce in a predetermined position of the mold in advance. The piece must be correctly positioned and supported so that it cannot move. If the reinforcing piece moves during casting, there is a problem that the sliding of the brake shoe is not smooth or the contact with the end 7a of the brake shoe is inconvenient.

A large number of such reinforcing pieces, such as eight to ten pieces, are required, and it takes about 20 seconds to attach them to the mold, and it is difficult to automate this attaching operation. At present, the pressure casting methods such as the molten metal forging method and the die casting method are being automated, and only the point of embedding the reinforcing piece is a bottleneck in the production of the backing plate by the pressure casting.

The present invention is intended to facilitate the mounting of the reinforcing pieces, facilitate the operation thereof, and reduce the operation time.

[0014]

According to the present invention, a plurality of reinforcing pieces to be cast on a backing plate are integrally connected to each other so that the reinforcing piece can be easily attached to a mold before casting.

[0015]

Since a large number of reinforcing pieces to be embedded in the backing plate are integrally connected, the work of attaching the reinforcing pieces to the mold can be performed much more easily and quickly than attaching the individual fine reinforcing pieces separately, and it is not possible. There is less fear of non-defective products.

[0016]

1 to 3 show a first embodiment of the present invention.
FIG. 1 is a front view of a backing plate in which reinforcing pieces are embedded.
FIG. 2 is a sectional view taken along line BB of FIG. 1, and FIG.
4 to 6 show a second embodiment, FIG. 4 is a front view of a backing plate in which the reinforcing pieces are embedded, and FIG. 5 is a DD of FIG. 6 is a cross-sectional view of only the reinforcing piece taken along line EE in FIG.

In the first embodiment shown in FIGS. 1 to 3, the shape of the reinforcing piece 17 is changed to an arc-shaped two piece located on the brake shoe ledge surface.
Each of the ledge reinforcing portions 18, 18, an anchor reinforcing portion 19 connected to one end of each of the reinforcing portions, and a shaft hole reinforcing portion 20 for reinforcing the periphery of the shaft hole 3. It is formed by connecting the part 20 with a connecting piece 21 and integrally connecting the whole.

This reinforcing piece 17 is used for the backing plate 1.
1 and 2 are embedded in an aluminum material and joined as shown in FIGS.

In the second embodiment shown in FIGS. 4 to 6, the wheel cylinder 6 and the anchor 9 are also formed as part of the reinforcing piece 17a as the wheel cylinder reinforcing portion 6a and the anchor reinforcing portion 19a, and a plurality of ledge reinforcing portions 18a are provided. It is made separately, and the wheel cylinder reinforcement 6a, the anchor reinforcement 19a, the ledge reinforcement 18
a of each of the shaft hole reinforcing portions 20a for reinforcing the edge of the shaft hole 3.
Connected to the connecting pieces 21a, 21b and 21c to
"a" is integrally formed in the shape of a wheel and buried when casting an aluminum material to form a backing plate.

The reinforcing pieces 17, 1 of the first and second embodiments described above.
7a is formed integrally by connecting the ledge surface, the anchor side surface, and the reinforcing portion for reinforcing the periphery of the shaft hole with the connecting pieces 21, 21a and 21b, so that the backing plate is attached to the mold when pressure-casting the backing plate. Only needs to be done once.

In the backing plate of the first embodiment shown in FIGS. 1 to 3, the wheel cylinder 6 and the anchor 9 are made of aluminum simultaneously with the pressure casting of the aluminum backing plate, and the bolt insertion holes 4 are also formed in the aluminum. However, the second embodiment of FIGS. 4 to 6 has a wheel cylinder,
Since the anchor is also made as a part of a reinforcing piece of a material stronger than the aluminum material, it becomes stronger than the backing plate of the first embodiment, and separately from the backing plate which does not heat-treat the heat treatment of the wheel cylinder, inner diameter finishing etc. There are advantages to do. Although the aluminum material is used as the material of the backing plate in this embodiment, magnesium or a magnesium alloy, zinc, or a zinc alloy may be used in consideration of vibration damping.

[0022]

[Effect of the Invention] (1) Since the reinforcing pieces are formed by integrally connecting reinforcing parts dispersed at several places of the backing plate, this is embedded in a light metal such as aluminum or a light alloy or a composite material thereof. When the backing plate is subjected to pressure casting, the number of steps for attaching the mold to the mold is simplified, and reliable attachment can be quickly performed.

(2) It becomes easy to automate the production of a backing plate in which a reinforcing piece is embedded in a light metal such as aluminum or a light alloy or a composite thereof.

(3) If the wheel cylinder is formed as a part of the reinforcing piece, a wheel cylinder having high strength and high dimensional accuracy can be manufactured.

[Brief description of the drawings]

FIG. 1 is a front view of a backing plate showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a partial perspective view of a reinforcing piece as viewed in a direction indicated by an arrow C in FIG. 1;

FIG. 4 is a front view of a backing plate showing a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line DD of FIG. 4;

FIG. 6 is a sectional view of only the reinforcing piece taken along line EE in FIG. 4;

FIG. 7 is a front view of a conventional backing plate to which components are attached.

FIG. 8 is a front view of the backing plate of the invention according to the pressure casting method.

FIG. 9 is a sectional view taken along line AA of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Backing plate 1a Folding edge 2 Drum 3 Shaft hole 4 Bolt insertion hole 5 Hole 6 Wheel cylinder 6a Wheel cylinder reinforcement 7 Brake shoe 7a End 7b End 8 Hold down device 9 Anchor 9a Tack 10 Return spring 11 Return spring 12 Parking Brake lever 13 Axis 14 Cable guide 15 Hole 16 Dust shield 17 Reinforcement piece 17a Reinforcement piece 18 Ledge reinforcement 18a Ledge reinforcement 19 Anchor reinforcement 19a Anchor reinforcement 20 Shaft hole reinforcement 20a Shaft hole reinforcement 21 Connection piece 21a Connection piece 21b Connecting piece 21c Connecting piece

Claims (4)

(57) [Scope of request for utility model registration] 1. A backing plate manufactured by pressure casting of a light metal such as aluminum or a light alloy or a composite material thereof, wherein a high-strength reinforcing piece is embedded and reinforced during the pressure casting to form an integral type for a drum brake. In the backing plate, the reinforcing piece (17) includes a ledge reinforcing portion (18) for reinforcing a brake shoe ledge surface,
An integrated backing plate for a drum brake, wherein an anchor reinforcing portion (19) for reinforcing an anchor and a shaft hole reinforcing portion (20) for reinforcing the periphery of the shaft hole are integrally connected. 2. A ledge reinforcing portion (18) of a reinforcing piece (17).
Has an arc shape, and the anchor reinforcing portion (19) is connected to one end of the ledge reinforcing portion (18) so as to reinforce the side surface of the anchor, and the shaft hole reinforcing portion (20) and the ledge reinforcing portion (18) are connected to each other. 2. An integrated backing plate for a drum brake according to claim 1, wherein the backing plate is integrally connected by connecting pieces (21). 3. A plurality of ledge reinforcing portions (18a) for intermittently reinforcing a brake shoe ledge surface.
2. The integrated backing plate for a drum brake according to claim 1, wherein the backing plate is integrally connected to the shaft hole reinforcing portion (20a) by a plurality of connecting pieces (21a). 4. The reinforcing piece (17a) further includes a shaft hole reinforcing part (2).
0a) has a wheel cylinder reinforcing part (6a) connected by a connecting piece (21b), and the anchor reinforcing part (19a) is connected to a shaft piece reinforcing part (20a) by a connecting piece (21c).
2. The integrated backing plate for a drum brake according to claim 1, wherein the backing plate is connected by: