JPH081305Y2 - Disc brake pad wear detector mounting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a mounting structure for easily and detachably mounting a pad wear detector to a disc brake pad.

[Conventional technology]

An electric wear detector used to detect wear of a disc brake pad detects the wear limit based on the principle that when the pad wears to a set position, the electric wire inside is cut off and the current is cut off. Therefore, it is required to attach the pad in a state in which the relative position with the pad is accurately maintained and also the holding stability is excellent.

Therefore, a representative conventional example of the mounting structure used is shown in FIGS. 5 and 6.

In the structure shown in FIG. 5, a notch portion 15 communicating with a hole on the rear surface of the lining 3 is provided on the peripheral portion of the pad back plate 2, the detector 5 is fitted into the notch portion from the rear, and an inlet of the notch portion is provided to prevent coming off. It is closed with a piston or shim.

Further, in the structure of FIG. 6, a metal tube 17 is press-fitted into the through hole 16 provided in the back plate 2 from the front side of the back plate, and the detector 5 is inserted into this tube to detect the check claw 18 in the tube. It is to be locked to the constricted part of the body.

[Problems to be solved by the device]

The mounting structure shown in Fig. 5 needs to prevent the detector from coming off.
The mounting position of the detector is restricted by the pressing portion of the pad. Further, in order to eliminate the restriction, it is necessary to interpose a shim or the like between the pad and the pressing member (outer pawl of the piston or caliper), and in either case, the degree of freedom in detection is insufficient.

On the other hand, in the mounting structure shown in FIG. 6, since the detector once mounted on the pad cannot be removed by the check claw, even if the detector can be reused when the pad is replaced, the detector must be replaced. , Financial loss.

The present invention seeks to provide a mounting structure effective for solving these problems.

[Means for solving the problem]

In this invention, a cutout portion having a larger inner diameter d than the width W of the inlet portion is provided in the peripheral portion of the pad back plate. Also,
In the wear detector, the width S of the narrow part is smaller than W, the width S ₁ of the wide part
Is a flat constricted portion with W <S ₁ <d, a protrusion having a diameter larger than d, which is located in front of and behind the constricted portion and is in contact with the front and rear surfaces of the back plate, and a retainer locking groove. Then, the constricted part of this wear detector is inserted in the cutout part of the pad back plate in a specific direction, and is rotated by approximately 90 ° at the insertion end position. After that, a retainer including an entrance of the cutout portion, two detent portions fitted into the locking groove, and an elastic arm clasped to the outer periphery of the rear side of the detector is assembled to prevent the detent of the detector.

[Action]

Since the width S of the narrow width portion of the constricted portion of the detector is smaller than the entrance width W of the cutout portion, the narrowed portion can be freely inserted into and removed from the cutout portion in a specific direction. Also, the width of the widening part of the constriction
Since S ₁ is larger than W, it cannot be removed in the entrance direction of the notch if it is rotated by a predetermined angle in the depth of the notch. At this time, the large-diameter portion before and after the constriction serves as a stopper to prevent the detector from moving in the axial direction. Can be held.

Also, if you remove the retainer, the detent will be released and you can remove it in the reverse order of mounting.

〔Example〕

 1 to 4 show an embodiment of the present invention.

As shown in FIG. 1, a notch portion 4 having a hole d on the inner side than the width W of the inlet portion is provided in the peripheral portion of the pad back plate 2. The notch 4 in the figure is formed in the center of the pad 1 on the disk center side. Further, as shown in FIG. 4, the lining 3 is partially removed at a portion corresponding to the notch in order to avoid interference with the detector.

On the other hand, in the wear detector 5, the width S of the narrow portion is S <W and the width S ₁ of the wide portion is W <S ₁ <d The protrusions 7 and 8 and the retainer locking groove 9 are provided. The retainer locking groove 9 provided at two places on the outer periphery of the rear portion of the detector is located on the extension line of the end face 5a in the narrow width direction, the groove bottom of which extends from the tip to the protruding portion 8.

The axial length of the constricted portion 6 is substantially equal to the thickness of the pad back plate 2.

Reference numeral 10 in FIG. 1 is a retainer that prevents the detector from rotating. This retainer 10 is a 90 ° bent detent that fits into one end and the other end of a flat portion 11 that is placed along the end face 5a of the detector, one at the inlet of the notch 4 and the other at the retainer locking groove 9 of the detector. It has parts 12 and 13. Further, on both sides of the flat portion 11, there are provided a pair of elastic arms 14 on the back surface side of the back plate 2 so as to hold the outer periphery of the detector from both sides.

The detector 5 is inserted into the notch 4 with the constricted portion 6 rotated 90 ° from the state shown in FIG. 1, and then rotated by approximately 90 ° in the depth of 4 and attached to the back plate 2. After that, as shown in FIGS. 2 and 3, when the retainer 10 is attached to the outer periphery of the rear portion of the detector 5 so as to be hugged and assembled, the retainer 12 is fitted to the entrance of the notch 4 to prevent the retainer from rotating. The detent portion 13 fitted in the groove 9 detents the detector. Also, in this state, the protrusion 7 is on the front surface of the back plate,
8 hits the rear surface of the back plate. Therefore, the detector 5 is prevented from rotating and moving in the axial direction, and is stably held in a fixed position.

Further, when the retainer 10 is removed, the detent is released, so that the retainer 10 can be removed from the notch.

〔effect〕

As described above, in this invention, the detector is engaged with the notch of the back plate by the relative rotation with the pad back plate so that there is no movement in both the axial direction and the radial direction, and then the detector is rotated by the removable retainer. Since it is stopped so as to satisfy the requirement for holding the fixed position, the mounting position of the detector is not limited, and extra parts such as shims are unnecessary.

Also, the detector can be replaced with a new pad and reused, which is advantageous in terms of the layout and effective use of the detector.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an example of a mounting structure of the present invention, FIG. 2 is a bottom view of a main part showing a mounting state of a wear detector, FIG. 3 is a rear view thereof, and FIG. 4 is a pad. FIG. 5 is a front view showing a notch forming portion of the back plate, and FIGS. 5 and 6 are sectional views showing an outline of a conventional mounting structure. 1 ... Pad, 2 ... Pad back plate, 3 ... Lining,
4 ... Notch, 5 ... Detector, 6 ... Constriction, 7, 8
…… Projection, 9 …… Retainer locking groove, 10 …… Retainer,
11 …… Flat part, 12, 13 …… Rotation prevention part, 14 …… Elastic arm.

Claims (1)

[Scope of utility model registration request] 1. A notch having a larger inner diameter d than the width W of the inlet is provided in the peripheral portion of the pad back plate, and the wear detector has a width S of the narrow portion smaller than W and a width of the wide portion. S ₁
Is a flat constricted portion with W <S ₁ <d, a protrusion having a diameter larger than d that is located in front of and behind the constricted portion and is in contact with the front and rear surfaces of the back plate, and a retainer locking groove. After inserting the constriction part of the wear detector into the notch of the pad back plate with a specific orientation, rotate it by about 90 °, and then insert the notch and the two detents that fit into the locking groove. A wear detector mounting structure for a disc brake pad, in which a retainer having an elastic arm clinging to the rear side outer periphery of the detector is assembled to prevent the detector from rotating.