JPH1078066A - Brake shoe for drum brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise in braking and prevent strength from degrading even if wear to a lining regresses by forming a recessed part having a bottom surface parallel to the peripheral surface of a rim. SOLUTION: Recessed parts 11, 11 whose cross-section shape running along the peripheral surface of the rim 4 is triangular are formed on both sides of the front end part of a lining 5, out of a vertical surface 9 whose ridge 5d serves as an upper end and a bottom surface 10 which spreads parallel to the peripheral surface of the rim 4 laterally from the bottom of the vertical surface 9. The positions of ridges 5c, 5d to drum inner periphery are still in the initial condition and unchangeable even if the lining 5 is worn, so that a noise reduction effect in the initial condition is maintained. By making the front end part of the ridge 5d on both sides of the end part parallel to the drum rotation direction and cutting drum rotation side upper end part diagonally, a diagonal surface may be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake shoe for a drum brake, which is brought into pressure contact with an inner peripheral surface of a drum at the time of braking to brake wheels via a drum by a frictional action.

[0002]

2. Description of the Related Art Drum brakes have been used for a long time as braking devices for automobiles, and there are various types, but the basics of operation are the same for all types. That is,
As shown in FIG. 10, a drum 1 that rotates in conjunction with wheels
A brake shoe 2 composed of a web 3, a rim 4, and a lining 5 attached to the peripheral surface of the rim, and having an overall
It is provided movably on a backing plate (not shown), and supplies pressure oil to a wheel cylinder (not shown) to push the brake shoe 2 toward the peripheral wall 1a of the drum 1 during braking, and presses the lining 5 against the inner peripheral surface 1b of the peripheral wall 1a. Then, the drum 1 is braked by the frictional action. Thereby, the wheels linked to the drum are braked.

[0003] In the brake shoe constructed as described above, if the end face of the lining 5 is cut off vertically as shown in FIG. Generates noise. That is, although the inner peripheral surface 1b of the drum is finished in a smooth cylindrical shape,
It is inevitable that minute irregularities remain. The large number of minute projections rapidly and continuously collide with the ridge 5a on the inflow side during braking, so that the lining vibrates at the portion of the ridge 5a, thereby generating a loud noise.

In order to avoid the above phenomenon, FIGS.
When the slope 6 is formed by cutting the portion of the ridge line 5a and the ridge line is retracted to the ridge line 5b, the collision between the ridge line 5b and the minute convex portion on the inner peripheral surface of the drum is alleviated and noise is reduced. .

However, in this case, the fulcrum 7 of the web 3
Is larger than the distance b between the ridge line 5a and the fulcrum 7, which undesirably reduces the strength of the end portion of the brake shoe.

Therefore, a configuration described in Japanese Utility Model Laid-Open No. 7-18041 has been proposed. This configuration, as shown in FIG.
In the configuration shown in FIG. 10, both side surfaces of the end are cut off from a ridgeline 5d that is inclined with respect to the drum infeed direction to form inclined surfaces 8,8. As a result, the ridge line 5c does not recede from the edge of the lining, but is shorter than the ridge line 5a (FIG. 10), so that the generated noise is reduced and the strength can be prevented from being reduced.

[0007]

In the brake shoe 2 having the structure shown in FIG. 13, when the lining 5 is worn due to the use of the brake, the slope 8 gradually becomes smaller, and the ridge 5c is formed.
The longer the effect, the earlier the effect fades. In the case where the lining 5 is press-molded with a mold, the size of the slope 8 varies due to the polishing finish after the molding, and it becomes difficult to obtain a brake shoe of a fixed shape.

[0008]

The present invention has solved the above-mentioned problem by forming a concave portion having a bottom surface substantially parallel to the peripheral surface of the rim instead of the slope 8 in the configuration shown in FIG. It is.

[0009]

The end of the lining 5 on the drum reciprocating side is a ridge line 5c.
Does not recede, the strength of the end of the brake shoe does not decrease. Further, since the ridgeline 5c is shorter than the ridgeline 5a, noise generation is reduced. Also, even if the lining wears due to the use of the brake, the cross-sectional shape of the concave portion along the peripheral surface of the rim 4 does not change, so that the noise prevention effect is unchanged. Furthermore, by setting the thickness of the lining at the bottom of the recess to the limit thickness of the lining, the wear state of the lining can be easily known visually through a viewing hole provided in the backing plate.

[0010]

1 to 9 show an embodiment of the present invention with respect to one end of a brake shoe. FIG. 1 is a side view of a first example, FIG. 2 is a plan view thereof, and FIG. Perspective view of the
4 is a side view of the second example, FIG. 5 is a plan view thereof, FIG. 6 is a plan view of the third example, FIG. 7 is a perspective view thereof, FIG. 8 is a side view of the fourth example, and FIG. FIG. Hereinafter, the same parts as those of the conventional example are denoted by the same reference numerals, and the description thereof will be omitted.

The first example shown in FIGS. 1 to 3 is a ridge line 5d shown in FIG.
Instead of the inclined surface 8 having the upper edge as the upper edge, a vertical surface 9 having the ridge line 5d as the upper edge and a bottom surface 10 extending from the bottom of the vertical surface 9 to be substantially parallel to the peripheral surface of the rim 4 are provided. Recesses 1 having a triangular cross section along the peripheral surface of the rim on both sides of the rim
1 and 11 are formed. For this reason, even if the lining 5 is worn, the positions of the ridge lines 5c and 5d with respect to the drum inner peripheral surface 1b remain unchanged in the initial state, so that the noise reduction effect in the initial state of the lining 5 of the prior invention of FIG. You.

In the second example shown in FIGS. 4 and 5, the lining surface is beveled at the ridge line 5c in FIG.
Is formed. The ridge line 5c slightly moves to the ridge line 5e. According to this configuration, noise generated due to friction of the ridge line 5e with the inner peripheral surface of the drum is further reduced. Rim 4
The distance c between the fulcrum 7 and the ridge line 5e is larger than the same distance b in the first embodiment, but is not as large as the conventional distance a (FIG. 11), so that the decrease in brake shoe strength is small.

FIGS. 6 and 7 show a ridge line 5 on both sides of the end portion.
This is an example in which the leading end of d is made parallel to the drum inflow direction, and the upper end of the drum inflow side is beveled to form a slope 13. According to this configuration, even if the lining is worn, the ridge 5
Since the length of f does not increase, there is no increase in noise due to the increase in the length of the ridgeline 5f.

FIGS. 8 and 9 show a fourth example of the slope 13 of the third example.
Is formed to extend to the bottom end portion of the concave portion 11 to form a slope 13a. When the lining is worn down to the bottom of the concave portion 11, the contact between the wider end of the lining and the inner peripheral surface of the drum can be loosened. In any of the above-described embodiments, the thickness of the lining at the bottom of the concave portion 11 is set to the wear limit thickness of the lining, so that the wear state can be easily visualized from the viewing hole formed in the corresponding backing plate. You can know. As an example of the wear limit thickness, the drum inner diameter is 3
For a brake having a thickness of 20 mm and a lining thickness of 10 mm, the appropriate wear limit thickness was 2 mm for a type in which the lining was bonded to a rim, and 4 to 5 mm for a rivet connection type.

[0015]

【The invention's effect】

(1) Slope 8 on both sides of the leading edge of the lining drum
The initial effect of the prior invention (FIG. 13), in which the noises during braking are not reduced and the strength is not reduced by forming 8, can be maintained even if the lining wear progresses.

(2) Recess 11 for obtaining this effect
Can be formed at once when the lining is pressed.

(3) By press molding, a lining with dimensional accuracy and constant quality can be obtained.

(4) If a viewing hole is formed in the backing plate of the brake and the side of the lining is viewed from here, the wear condition of the lining can be easily known.
That is, by setting the thickness of the lining at the bottom of the concave portion 11 to the wear limit thickness of the lining, it is possible to visually know the replacement time of the lining.

[Brief description of the drawings]

FIG. 1 is a side view of a first example of an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a perspective view of this.

FIG. 4 is a side view of a second example of the embodiment.

FIG. 5 is a plan view of this.

FIG. 6 is a plan view of a third example of the embodiment.

FIG. 7 is a perspective view of this.

FIG. 8 is a side view of a fourth example of the embodiment.

FIG. 9 is a plan view of this.

FIG. 10 is a side view showing a basic type of a brake shoe for a drum brake.

FIG. 11 is a side view showing a conventional example in which the leading end of the lining into the drum is obliquely cut.

FIG. 12 is a plan view of the same.

FIG. 13 is a perspective view of a brake shoe of the invention of the related art in which this is improved.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drum 1a Peripheral wall 1b Inner peripheral surface 2 Brake shoe 3 Web 4 Rim 5 Lining 5a-5f Ridge line 6 Slope 7 Support point 8 Slope 9 Vertical surface 10 Bottom surface 11 Concave side Slope 13, 13a Slope

Continued on the front page (72) Inventor Hideaki Shima 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation

Claims (2)

[Claims] The rim comprises a web (3), a rim (4) and a lining (5) mounted on the periphery of the rim.
In the brake shoe for a drum brake having an overall shape of an arc, the leading end of the lining on the drum inflow side is a vertical surface, and on both sides thereof, a vertical surface (9) approaching each other toward the leading end of the lining; A brake shoe for a drum brake, wherein a bottom surface (10) substantially parallel to the peripheral surface forms a recess (11) having a triangular cross section parallel to the peripheral surface of the rim. 2. The brake shoe for a drum brake according to claim 1, wherein the thickness of the lining at the bottom of the concave portion is set to a lining wear limit thickness.