JPS6410694B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a shun hold down device for a drum brake.

PRIOR TECHNOLOGY Conventionally, a pin type shew hold down device has been used for drum brakes. A pin passing through the web of the user, two cups provided between the web and a locking head located on the web side of the pin, and having the pin penetrated through the center thereof, and provided between the two cups, It consists of a compression spring, one end of which is fitted into a cup on the side of the locking head, and the other end fitted into a cup on the side of the web, and the pin, compression spring, and two The cup protrudes, and the pins protrude from the back side of the web all the way to the back plate.

Problems to be Solved by the Invention However, in a drum brake equipped with such a shoe hold-down device, when a parking lever, an adjustment lever, etc. are arranged on the web of the brake shoe on the back plate side of the web, However, since it is necessary to prevent these from interfering with the portion located between the web of the pin and the back plate, there is a problem in that the installation space for the parking lever, adjustment lever, etc. is limited. This becomes particularly noticeable when drum brakes are downsized in line with recent trends in vehicle weight reduction.

On the other hand, as described in Japanese Utility Model Publication No. 54-41914, for example, a linear spring member is disposed between both brake shoes with its intermediate portion fixed to the back plate, and the linear spring member is If both ends of the spring member are used to press both brake shoes against the back plate, there will be no shoe hold-down device between the brake shoes and the back plate. It is thought that sufficient space can be secured for installation of parking levers etc.

However, in this case, since the intermediate portion of the linear spring member is located on the inner circumferential side of the back plate, when assembling the drum brake to the non-rotating member on the inner circumferential side of the back plate, the linear spring member This may get in the way and interfere with the drum brake assembly work.

The present invention has been made against the background of the above-mentioned circumstances, and its object is to create a system that can secure sufficient installation space for parking levers, etc. without causing any hindrance to the assembly work of drum brakes. An object of the present invention is to provide a u-hold down device.

Means for Solving the Problems In order to achieve the above object, the present invention has a plate-shaped and arc-shaped web, and the web is disposed on the back plate in a state substantially parallel to the back plate. The drum brake includes a pair of brake shoes and an anchor block which is fixed on the back plate of the pair and comes into contact with one end of the brake shoes to receive the drag force acting on the brake shoes during braking. A shoe hold-down device for movably supporting a brake shoe along the back plate, the brake shoe being (a) attached in a cantilevered manner to a surface of the anchor block opposite to the back plate; (b) a shoe hold down bracket extending from the anchor block along an arc of the web facing the surface of the brake shoe web opposite the back plate side; and (b) a free end of the shoe hold down bracket. and a spring provided between the brake shoe and the web of the brake shoe to press the brake shoe against the back plate.

Operation and Effects of the Invention According to the shew hold down device configured as described above, the shew hold down bracket, which is attached in a cantilever manner to the surface of the anchor block opposite to the back plate side, The brake shoe is located on the side opposite to the back plate side of the web of the brake shoe, and the brake shoe is pressed against the back plate by a spring provided between the free end of the shoe hold down bracket and the web of the brake shoe. It will be done. Therefore, there is no shoe hold-down device between the brake shoe and the back plate, making it possible to secure sufficient installation space for the parking lever, etc. disposed between the brake shoe and the back plate. .

Moreover, since the shoe hold down bracket extends from the anchor block along the arc of the web while facing the surface of the web of the brake shoe on the side opposite to the back plate side,
A sufficient space can be secured on the inner circumferential side of the back plate, and thereby the above effects can be obtained without causing any hindrance to the assembly work of the drum brake to the non-rotating member.

The above-mentioned shew hold down bracket is configured to have, for example, two arm portions extending in an arc shape from the anchor block so as to form a substantially U-shape as a whole.

Further, when a retainer spring is installed between one end of a pair of brake shoes to urge both brake shoes toward the anchor block, the above-mentioned shoe hold down bracket is preferably attached to both brake shoes. The retainer spring is configured to also function as a retainer plate, with a retaining portion that prevents one end from coming off the anchor block and presses the center portion of the retainer spring toward the back plate.

The spring is preferably a compression coil spring, with one end of the compression coil spring seated on a seat formed at the free end of the show hold down bracket, and the other end of the compression coil spring made of synthetic resin. It is configured to be seated on the web via a sheet member.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIGS. 1 and 2, a pair of brake shoes 2 and 4 are disposed on a back plate 14. As shown in FIGS. One ends of the brake shoes 2 and 4 are respectively engaged with a pair of pistons (not shown) of a wheel cylinder 8 fixed on a back plate 14 by the biasing force of a return spring 6. , 4 are brought into contact with an anchor block 12 fixed on a back plate 14 by the biasing force of a retainer spring 10, respectively. Brake shoes 2 and 4 are
It has a plate-shaped and arc-shaped web 20, and the web 20 is connected to the back plate 14.
It is placed almost parallel to the A bulging portion 13 bulging toward the center of the drum brake is formed in the longitudinal center of the web 20 .

A parking lever 1 is mounted on the surface of the web 20 of the brake shoe 2 located on the back plate 14 side.
6 and an adjustment lever 18 are rotatably attached by a common pin near the wheel cylinder 8, with the parking lever 16 sandwiched between the adjustment lever 18 and the web 20. The adjustment lever 18 is biased toward the rim (clockwise in FIG. 1) by a tension spring 22, and is engaged with the parking lever 16 by a claw portion 24 at the end. A strut 2 is provided between the parking lever 16 and the web 20 of the brake shoe 2 to which it is pivotally connected, and the web 20 of the brake shoe 4.
6 is being bridged.

On the surface of the anchor block 12 opposite to the back plate 14 side, a shew hold down bracket (hereinafter abbreviated as bracket) 28, which has a generally U-shape, is riveted in a cantilevered manner at its center. has been done. Both arm portions of the bracket 28 are attached to the webs 20 of the brake shoes 2 and 4.
The anchor block 1 is attached along the arc of the web 20 while facing the surface opposite to the back plate 14 side of the anchor block 1.
The bracket 28 is provided with an edge 32 that stands up at right angles to the periphery of the bracket 28, reinforcing the bracket 28 itself against external forces in a direction perpendicular to the plate surface of the bracket 28. are doing. Note that both arm portions of the bracket 28 move away from the web 20 of the brake shoes 2 and 4 toward the tip, but the web 2
It fits within the width of the shurim located on one side of 0. Further, the bracket 28 is provided with a presser portion 30 that presses the retainer spring 10 toward the back plate 14, and the bracket 28 also serves as a retainer plate.

The free end of the bracket 28 is opposed to the bulge 13 of the web 20 of the brake shoes 2, 4, and a cylindrical protrusion 36 is provided at this free end, as shown in FIG. A sheet portion 34 having a sheet portion 34 is formed parallel to the web 20. One end of a compression coil spring 38 is fitted into this protrusion 36 .
The other end of 8 is seated on a disk-shaped synthetic resin sheet member 40 with raised edges. The compression coil spring 38 presses the seat member 40 against the web 20 and presses the entire brake shoe 2, 4 against the back plate 14.

The shoe hold-down device configured as described above can press the brake shoes 2 and 4 against the back plate 14 only from the front side (the side opposite to the back plate 14 side), and does not protrude at all from the back side. Therefore, sufficient installation space is secured for the parking lever 16, the adjustment lever 18, etc., which are arranged on the back side of the web 20, that is, between the web 20 and the back plate 14, and accordingly, the drum brake This makes it easier to downsize.

Furthermore, both arm portions of the bracket 28 extend in opposite directions from the anchor block 12 along the arc of the web 20 while facing the surface of the web 20 of the brake shoes 2 and 4 on the side opposite to the back plate 14 side. Since it is made to protrude and is accommodated in the space formed by the web 20 and the seal rim, a sufficient space can be secured on the inner peripheral side of the back plate 14. This results in
When assembling the drum brake to a non-rotating member such as an axle tube using bolts or the like on the inner circumferential side of the back plate 14, the shew hold-down device does not interfere with the assembly work of the drum brake.

Further, according to this embodiment, since the sheet member 40 is made of synthetic resin with a small coefficient of friction, the web 2
0, and hardly interferes with the movement of the brake shoes 2 and 4.

Next, another embodiment of the shut-down device is shown in FIG. In the figure, a circularly bulging coil spring fitting part 46 is formed in the center of the seat part 44 of the bracket 28, and a hole 48 is formed in the center of the coil spring fitting part 46. . The sheet member 58 includes a cup 50 made of synthetic resin with a small coefficient of friction, a knob portion 56 that stands upright at the center of the cup portion 50, has a head 52 at the tip, and has a protrusion 54 in the middle. It consists of The engagement between the seat member 58 and the seat portion 44 of the bracket 28 is achieved by forcing the protrusion 54 through the hole 48, thereby allowing the seat member 58 to be disposed between the seat portion 44 and the cup portion 50. The compression coil spring 38 is brought into a preloaded state. When assembling brake shoes 2 and 4,
Pinch the knob 56 to release the compression coil spring 3.
By pulling up against the elastic force of 8,
Since a sufficient space can be easily secured between the seat member 58 and the back plate 14, the assembly work of the brake shoes 2 and 4 can be performed efficiently.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a state in which a shuffle down device according to an embodiment of the present invention is assembled to a drum brake. FIG. 2 is a cross-sectional view taken in FIG. FIG. 3 is an enlarged view showing a main part of a cross section taken along the line - in FIG. 1. Fourth
This figure shows the main parts of another embodiment of the present invention, and corresponds to FIG. 3. 2, 4: Brake shoe, 10: Retainer spring, 12: Anchor block, 14: Back plate, 20: Web, 28: Shoe hold down bracket, 30: Presser section, 34, 44: Seat section, 38: Compression Coil spring, 40,5
8: Sheet member.

Claims (1)

[Scope of Claims] 1. A pair of brake shoes having plate-shaped and arc-shaped webs and disposed on the back plate in a state where the webs are substantially parallel to the back plate;
and an anchor block fixed on the back plate and in contact with one end of the brake shoe to receive the drag force acting on the brake shoe during braking, in which the brake shoe is connected to the back plate. A shoe hold down device movably supported along a plate, the shoe hold down device being cantilevered to a surface of the anchor block opposite to the back plate side, and supporting the back plate of the web of the brake shoe. a shu-hold down bracket extending from the anchor block along an arc of the web while facing opposite sides; a free end of the shu-hold down bracket and the web of the brake shoe; A shoe hold-down device for a drum brake, comprising a spring provided between the brake shoe and the back plate for pressing the brake shoe against the back plate. 2. The shew hold down for a drum brake according to claim 1, wherein said shew hold down bracket is provided with two arm portions extending in an arc shape from said anchor block, forming a generally U-shape as a whole. Device. 3 A retainer spring is stretched between one ends of the pair of brake shoes for urging both brake shoes toward the anchor block, and the shoe hold down bracket has one end of both brake shoes pressed against the anchor block. The drum brake according to claim 1 or 2, further comprising a presser portion that prevents the retainer spring from coming off from the block and presses the center portion of the retainer spring toward the back plate, and that also serves as a retainer plate. Show hold down device. 4. The spring is a compression coil spring, and one end of the compression coil spring is seated on a seat portion formed at the free end of the shew hold down bracket, and the other end is seated on a seat member made of synthetic resin. The shun hold down device for a drum brake according to claim 1, 2, or 3, which is seated on the web.