JPH112268A - A device for limiting the displacement of the parking lever for drum brakes - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To be able to freely set the amount of displacement, to prevent the inner cable of the control cable from being worn at the bent portion of the control cable in the cable guide portion, and to greatly improve the life of the control cable. An object of the present invention is to provide a displacement limiting device for a parking lever for a drum brake. SOLUTION: A conduit is slidably inserted into the conduit,
An inner cable provided with an abutment member at one end so that a parking lever in the brake drum can be operated in an operating direction, the control cable having the conduit fixed to a stationary portion, and a predetermined position of the conduit. One end is fixed, the other end is fixed to the parking lever, an urging means for urging the parking lever in a non-operation direction, the inner cable is slidably inserted, and one end is in contact with the end of the conduit. A stationary member having a predetermined length and a compressive load resistance provided so that the other end can contact the parking lever, and a tubular stopper member supported by a guide member provided at the stationary portion. And

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for limiting the amount of displacement of a parking lever for a drum brake (hereinafter simply referred to as "limiter"). More specifically, the present invention relates to a restriction device characterized by a tubular stopper member having a predetermined bending stiffness and a length provided to be inserted into an inner cable of a control cable for operating a parking lever in a brake drum.

[0002]

2. Description of the Related Art FIG.
As a device for limiting the maximum operation rotation position of a parking lever used for a brake drum 100 as shown in FIG.
As shown in FIG. 2, a stopper member S which is crimped to an intermediate portion of an inner cable Cin through which a bracket-shaped cable guide G is inserted is disclosed. In this case, the distance X between the position of the stopper member S and the cable guide when the brake is not operated is the displacement of the parking lever L.

Further, Japanese Patent Publication No. 7-10108 discloses a stopper member comprising a U-shaped cable guide or a cylindrical cable guide G through which an inner cable Cin is inserted, as shown in FIG. Have been. In this case, the distance X between the connection position between the parking lever and the inner cable Cin and the free end of the cable guide G when the brake is not operated is the displacement of the parking lever L.

[0004] Since each of the above-mentioned conventional restriction devices has a structure utilizing a cable guide provided on the back plate 2 of the brake drum 100 (see FIG. 7), the configuration and mounting position of the restriction device itself become complicated. However, there is a problem that there is no degree of freedom for setting the displacement amount.

Japanese Utility Model Publication No. Sho 62-13891 discloses a compression coil spring B inserted by an inner cable Cin inserted through a bracket-shaped cable guide G, as shown in FIG. An urging member including a compression coil spring B in which the guide G side is tightly wound and the other side is in contact with the parking lever L is disclosed. This is intended to reduce the inner cable wear of the cable guide portion, but is not sufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a drum brake which can freely set the amount of displacement, can prevent the control cable from being worn at the bent portion of the control cable in the cable guide portion, and can greatly improve the life of the control cable. An object of the present invention is to provide a parking lever displacement amount limiting device.

[0007]

SUMMARY OF THE INVENTION The limiting device of the present invention has a contact member which is slidably inserted into a conduit and has an end at one end so that a parking lever in a brake drum can be operated in an operating direction. A control cable in which the conduit is fixed to a stationary part, one end is fixed to a predetermined position of the conduit, the other end is fixed to a parking lever, and the parking lever is moved in a non-operation direction. A biasing means for biasing, the inner cable is slidably inserted, a predetermined length and a predetermined length provided so that one end is in contact with the end of the conduit and the other end is in contact with the parking lever. It is characterized by comprising a tubular stopper member having compression load performance and supported by a guide member provided in the stationary portion.

It is preferable that the biasing means is a compression coil spring, and the stopper member is a flat steel wire close-contact spring inserted through the inside of the compression coil spring.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS The limiting device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view of an essential part showing an example of a limiting device according to an embodiment of the present invention, FIG. 2 is a schematic explanatory view of a control cable for a brake drum including the limiting device of FIG. 1, and FIG. It is explanatory drawing which shows the state in which the 1 limiting device was provided in the back plate of the brake drum.

As shown in FIGS. 1 to 3, a limiting device 1 according to the present embodiment includes a conduit 10 and a sliding drum 10 which is slidably inserted into the conduit 10.
0 (see FIG. 7), the inner cable 2 having an abutment member 21 at one end so that the parking lever L in the operating direction can be operated in the operating direction.
0, and the conduit 10 has a control cable C fixed to the back plate 2 (stationary portion). In addition, inner cable 20
Is preferably coated with a coating material such as polyamide or polyethylene.

In the limiting device 1, one end e1 is fixed at a predetermined position of the conduit 10, and the other end e is fixed to the parking lever L.
2 is fixed, and includes a compression coil spring 30 (biasing means) for biasing the parking lever L in the direction of the arrow A (non-operating direction).

Further, the restriction device 1 includes a stopper member 3 supported by a pillow-shaped guide member 40 provided on the back plate 2.

The stopper member 3 is made of a flat steel wire contact spring 3a having a tubular outer shape, and has an inner cable 20 therein.
Are slidably inserted. One end E of the stopper member 3
a is in contact with the end of the conduit 10 and the other end Eb is in contact with the parking lever L. That is, when the parking lever L is not operated, the parking lever L is separated from the one end Ea of the stopper member 3 by the distance δ, and the distance from when the parking lever L is operated to abut on the one end Ea of the stopper member 3. δ is the parking lever L
Is the movable distance. The stopper member 3 has a predetermined length (8
5 mm) and the prescribed shrinkage load resistance (compression load of 1.18 kN: 12,000 to 1,000,000 times with drum stroke)
And

Further, the stopper member 3 has a thickness of about 0.05 to
0.15 N · m ^2, preferably has a bending stiffness 0.1 N · m ^2. In other words, the stopper member 3 of the present invention
Have both flexibility and rigidity.

The material of the flat steel wire contact spring 3a used as the stopper member 3 is made of Japanese Industrial Standard (JIS) G
A 3506 SWRH62A hard steel wire is suitably employed. The flat steel wire spring 3a has a width W of 2.76 m.
m, the thickness t is 1.3 mm, and the outer diameter D ₁ is 7.
Is 43 mm, the inner diameter _{D 2} is 4.8 mm (see FIG. 1).

[0017]

Next, the limiting device of the present invention will be described based on embodiments, but the present invention is not limited to only such embodiments.

Examples and Reference Examples 1 and 2 A control cable (inner cable) having the structure shown in Table 1
And a durability test was performed under the following test conditions.

[0019]

[Table 1]

Test conditions Load: 1.18 kN Stroke: Endurance by drum stroke: Endurance limit: 1 million times Speed: 30 cpm Ambient temperature: room temperature

As a result, in the case of Reference Example 1, the inner cable was broken at 193,000 times, and in the case of Reference Example 2, the inner cable was broken at 28,000 times.

On the other hand, in the case of the embodiment, it was found that the inner cable did not break even 1,000,000 times.

[0023]

According to the limiting device of the present invention, the displacement can be easily set only by replacing the stopper member. Further, the displacement of the parking lever can be limited without changing the conventional drum brake device.

Further, according to the limiting device of the present invention, the abrasion of the compression coil spring and the inner cable of the control cable can be prevented, and the life of the control cable can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing an example of a restriction device according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory view of a brake drum control cable including the restriction device of FIG. 1;

FIG. 3 is an explanatory diagram showing a state in which the limiting device of FIG. 1 is provided on a back plate of a brake drum.

FIG. 4 is an explanatory diagram illustrating an example of a conventional restriction device.

FIG. 5 is an explanatory diagram showing another example of the conventional restriction device.

FIG. 6 is an explanatory diagram showing still another example of the conventional restriction device.

FIG. 7 is an explanatory diagram showing an example of a conventional brake drum.

[Description of Signs] 1 Limiting device 2 Back plate 3 Stopper member 3a Flat steel wire tight contact spring 10 Conduit 20 Inner cable 30 Compression coil spring 40 Guide member C Control cable

Claims (2)

[Claims] 1. A conduit and slidably inserted into the conduit,
An inner cable provided with an abutment member at one end so that a parking lever in the brake drum can be operated in an operating direction, the control cable having the conduit fixed to a stationary portion, and a predetermined position of the conduit. One end is fixed, the other end is fixed to the parking lever, an urging means for urging the parking lever in a non-operation direction, the inner cable is slidably inserted, and one end is in contact with the end of the conduit. A drum brake having a predetermined length and a compressive load resistance provided so that it can come into contact with the other end of the drum and a parking lever, and a tubular stopper member supported by a guide member provided at a stationary portion. Parking lever displacement limiter. 2. The urging means is a compression coil spring,
2. The displacement limiting device for a parking lever for a drum brake according to claim 1, wherein the stopper member is a flat steel wire contact spring inserted through the inside of the compression coil spring.