JPH0754889A - Abrasion alarm device for disk brake - Google Patents

Abstract

PURPOSE:To install simply a sensor plate on a friction pad for a disk brake CONSTITUTION:A dowel 31 is protruded on the back plate 24 of a friction pad 23, and a sensor plate 32 which consists of a U-shaped fixed part 33 having a fitting hole for fitting the dowel 31, a spring part 34 curved the back side of the back plate 24 from the fixed part 33, and a vibration part 35 extending from the spring part 34 to a disk D side is prepared. A bent piece part 38 standing up from the fixed part 33 is provided on the sensor plate 32, the fixed part 33 of the sensor plate 32 is inserted to the back plate 24 serving the bent piece part 38 as a guide, the dowel 31 is rode over by means of slight expansion of the fixed part 33, and also a position is fixed by utilizing the pushing force of the vent piece part 38 and fitting of the dowel 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake wear alarm device for warning the wear limit of a friction pad of a disc brake.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 7, a wear alarm device of this type is generally provided with a friction pad 3 composed of a back plate 1 and a lining material 2 bonded to the surface of the back plate 1 as described above. A dowel 4 is provided on the back surface of the side edge portion of the plate 1, and the sensor plate 5 is fitted to the dowel 4 to prevent the caulking. The sensor plate 5 includes a fixing portion 6 which fits the dowel 4 and is closely attached to the back plate 1, a spring portion 7 in which the back surface side of the back plate 1 is bent from the fixing portion 6, and a disk from the spring portion 7. When the lining material 2 of the friction pad 3 reaches the wear limit L, the oscillating portion 8 linearly extended toward D
The vibrating portion 8 comes into contact with the disk D, and an abnormal noise is generated to inform the wear limit. A similar wear alarm device is disclosed in Japanese Utility Model Laid-Open No. 4-31346. Further, in the figure, 9 is a recess formed when the dowel 5 is stretch-formed.

[0003]

However, according to the above-mentioned conventional wear alarm device, since it is indispensable to prevent the sensor plate 5 from being caulked against the friction pad 3, a separate caulking step is set when the disc brake is assembled. However, there is a problem that an increase in cost burden cannot be avoided. Also, the caulking work is performed with the friction pad 3
Since it has to be performed in a narrow range of the side edge portion of the back plate 1 which avoids the interference with the lining material 2, it is very troublesome, and it takes a lot of time for the caulking work to sacrifice the productivity. There was also.

The present invention has been made in view of the above problems of the prior art, and provides a wear alarm device for a disc brake in which a sensor plate can be easily attached to a friction pad without using crimping. With the goal.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a friction pad comprising a back plate and a lining material bonded to the surface of the back plate, the back plate being in contact with a disk. In a disc brake wear alarm device having a sensor plate that generates a sound and warns the wear limit of the lining material, a dowel is provided on the back side of the side edge portion of the back plate,
The sensor plate includes a fixed portion having a U-shaped cross section that can be inserted into a side edge portion of the back plate, a spring portion in which the back surface side of the back plate is bent from the fixed portion, and a straight line from the spring portion toward the disk. The fixed portion has a distance between the two facing pieces set to be smaller than the thickness of the back plate including the dowel, and the dowel is fitted to one of the facing pieces. And a back plate which is erected on both sides of the one opposing piece with the engaging hole therebetween and stands up toward the other opposing piece of the fixing portion and cooperates with the other opposing piece. It is characterized in that a bent piece portion for sandwiching is provided.

[0006]

In the disc brake wear alarm device constructed as described above, when the U-shaped fixing portion of the sensor plate is inserted into the side edge portion of the back plate of the friction pad, a bending piece provided on one of the opposing pieces. The portion serves as a guide to easily get over the dowel and fit the dowel into the engaging hole. Moreover, after the fixing portion is inserted, the bending piece portion and the other opposing piece of the fixing portion cooperate to hold the back plate, so that the holding force and the fitting of the dowel allow the sensor plate to move. It is securely fixed to the friction pad.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 5 and 6 show the overall structure of a disc brake equipped with a wear alarm device according to the present invention. In these drawings, 11 is a carrier fixed to a non-rotating portion (not shown) of the vehicle body, and is a mounting hole 1 to the vehicle body.
2, a pair of bridge portions 14 extending from the main body portion 13 across the disc D, and a leg portion 15 extending inward from the respective bridge portions along the disc D in the radius thereof. Is equipped with. A caliper 17 is slidably supported on the carrier 11 by using a carrier pin 16 (FIG. 6). The caliper 17 includes a cylinder portion 18 in which a piston (not shown) is slidably mounted, and the cylinder portion 1
8 includes a bridge portion 19 extending over the disk D, and a pair of claw portions 20, 20 extending from the bridge portion 19 along the disk D inwardly of its radius.

The body 13 and the legs 15 of the carrier 11
As shown in FIG. 5, two step portions 21 (the main body portion 13 side is omitted) are formed facing each other at a distance from each other in the circumferential direction of the disk D.
Inner friction pad (inner pad) 22 on the side step
However, outer friction pads (outer pads) 23 are placed on the step portions 21 on the leg 15 side, respectively. Each of the friction pads 22 and 23 is composed of a back plate 24 and a lining material 25 joined to the surface of the back plate 24, and the lining material 25 is arranged so as to face the disk D. The friction pads 22 and 23 are connected to the bridge portion 14 of the carrier 11.
The upper end of the plate spring 26 is fixed by the plate spring 26 and is maintained parallel to the plate surface of the disk D. Reference numeral 27 is a squeal preventing shim, which is connected to the back surface side of the back plate 24 of each of the friction pads 22 and 23.

In such a disc brake, when brake fluid pressure acts on the oil chamber in the cylinder portion 18 of the caliper 17, a piston (not shown) advances to press the inner pad 22 against one side of the disc D, while The reaction causes the caliper 17 to move in the direction opposite to the piston and presses the outer pad 23 against the other surface of the disc D, whereby the rotation of the disc D is suppressed.

On both sides of the lower portion of the outer pad 23, there are formed ears 27 extending in the circumferential direction of the disc D as shown in FIG.
A wear alarm device 30 according to the present invention is attached.
As shown in FIGS. 1 to 4, the wear alarm device 30 is attached to the back plate 24 by utilizing the dowel 31 protruding from the back surface of the side edge of the back plate 24 of the outer pad 23 and the dowel 31. It consists of a sensor plate 32. The sensor plate 32 has a fixing portion 33 having a U-shaped cross section that can be inserted into a side edge portion of the back plate 24.
And a spring portion 34 in which the back side of the back plate 24 is bent from the fixed portion 33, and a vibrating portion 35 linearly extended from the spring portion 34 toward the disk D. The dowel 31 is formed by subjecting the back plate 24 to extrusion molding, and the recess 36 formed by the above-mentioned extrusion molding is formed on the surface of the back plate 24. Further, the fixed portion 33 is formed in a bifurcated manner from the bottom portion to the lower side.

The fixing portion 33 of the sensor plate 32 is one of the two opposing pieces 33a and 33b having a U-shape.
3a is provided with an engaging hole 37 into which the dowel 31 is fitted, and the other facing piece 33a is provided on both sides of the one facing piece 33a.
A bending piece portion 38 that stands up toward b is provided. Here, the distance between the two facing pieces 33a and 33b of the fixed portion 33 is set to be smaller than a value (t + h) obtained by adding the thickness t of the back plate 24 and the height h of the dowel 31, and The height H of the bent piece portion 38 is set to be smaller than the height h of the dowel 31 and to form a gap with the other facing piece 33b that is slightly smaller than the thickness t of the back plate 24. There is.

In the wear alarm device 30 constructed as described above, when the U-shaped fixing portion 33 of the sensor plate 32 is inserted into the back plate 24 of the outer pad (friction pad) 23, the two opposing pieces 33a of the fixing portion 33 are inserted. , 33b is pushed apart by the dowel 31 to get over it, and the dowel 31 is fitted into the engaging hole 37. At this time, since the bending piece portion 38 is present on the one facing piece 33a of the fixing portion 33 having the engaging hole 37, the expansion margin, that is, the elastic deformation amount of the fixing portion 33 of the sensor plate 32 for overcoming the dowel 31. W
(Fig. 2) is slightly reduced, and the sensor plate 32 is attached to the friction pad 2
3 can be easily inserted into the back plate 24. Moreover,
By properly setting the height H of the bending piece portion 38 within the above range, after the fixing portion 33 is inserted into the back plate 24, the bending piece portion 38 and the other facing piece 33b of the fixing portion 33 are Cooperate to clamp the back plate, and the clamping force and the fitting of the dowels 31 securely fix the sensor plate 32 to the friction pad 23. Therefore, when the lining material 25 of the friction pad 23 reaches the wear limit L (FIG. 1), the vibrating portion 35 of the sensor plate 32 comes into contact with the disk D to generate abnormal noise, and the wear limit is detected. .

It is preferable that the dowel 31 has the same shape as the conventional caulking dowel 4 (FIG. 7) in the production of the back plate 24, but the dowel 4 has a considerable height for caulking. It is set high. Therefore, if the fixing portion of the sensor plate is formed so as to simply sandwich the back plate 24, the fixing portion will expand beyond the elastic limit when it is inserted. However, if the sensor plate 32 is formed as in the above-described embodiment, the bent piece portion 38 serves as a guide, and the fixed portion 33 rides over the dowel 34 (4) with a slight expansion, and thus the conventional caulking dowel 4 is provided. Can be used as it is.

[0015]

As described above in detail, according to the wear alarm device for a disc brake according to the present invention, the sensor plate can be easily and surely attached to the back plate of the friction pad by insertion. Therefore, since the caulking is unnecessary, the assembly cost of the disc brake can be reduced and the productivity can be greatly improved. Moreover, the existing dowels for caulking can be used for mounting, and the utility value thereof is great.

[Brief description of drawings]

FIG. 1 is a side view showing a wear alarm device for a disc brake according to the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a plan view of FIG. 1 viewed from the lower side.

FIG. 4 is a perspective view showing a shape of a sensor plate which constitutes the wear alarm device.

FIG. 5 is a front view showing the structure of a disc brake to which the present wear warning device is applied.

FIG. 6 is a plan view showing the structure of a disc brake to which the present wear warning device is applied.

FIG. 7 is a cross-sectional view showing a conventional wear alarm device.

[Explanation of symbols]

 23 Friction pad 24 Back plate 25 Lining material 31 Dowel 32 Sensor plate 33 Fixed part 33a Opposing piece 33b Opposing piece 34 Spring part 35 Vibrating part 38 Bending piece part D disk

Claims (1)

[Claims] 1. A sensor plate of a friction pad consisting of a back plate and a lining material bonded to the surface of the back plate, which produces a sound by contacting a disk on the back plate to warn the wear limit of the lining material. In the wear alarm device for a disc brake, the dowel is provided on the back side of the side edge of the back plate, and the sensor plate has a U-shaped fixing part that can be inserted into the side edge of the back plate. And a vibrating portion linearly extending from the spring portion toward the disc, the spring portion being bent from the fixed portion on the back surface side of the back plate, and the fixed portion including the two opposing portions. The distance between the pieces is set to be smaller than the thickness of the back plate including the dowels, and one of the facing pieces is provided with an engaging hole into which the dowel is fitted. The other facing piece standing on both sides toward the other facing piece of the fixing portion. A wear alarm device for a disc brake, which is provided with a bent piece portion for sandwiching the back plate in cooperation with the wear alarm device.