JPH081307Y2 - Brake pad wear detector mounting structure - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pad wear detector mounting structure.

[0002]

2. Description of the Related Art In order to detect the wear of a brake pad or lining, it has long been practiced to insert a detector (generally called a probe) at the wear limit position of the pad. There have been many ideas. Among these structures, a structure in which the detachability of the probe is taken into consideration is disclosed in, for example, Japanese Utility Model Publication No. 58-42665. This is because the pad back plate is provided with a through hole that leads to a blind hole in the friction material, and a cylindrical holding member is fixed to that hole, and a check claw cut and raised on the inner surface side of this holding member is attached to the step portion of the outer circumference of the probe. The probe that is locked and inserted into the holding member is held in a fixed position.

According to this structure, the outer circumference of the probe is partially recessed to form the above-mentioned step portion. Therefore, when the check claw is locked to the step portion, the probe is prevented from rotating by the contact pressure of the claw. To be done. Further, when the probe is rotated with a strong force, the portion without the step becomes a cam and the check claw comes off the step, and the probe can be pulled out from the holding member.

[0004]

The structure described above requires a holding member, and simplification of the structure is not yet sufficient. In addition, dedicated equipment such as a press machine is required when the holding member is press-fitted into the through hole of the pad back plate and when the probe is inserted into the holding member, which tends to increase the cost.

Further, since it is difficult to rotate the attached probe with a fingertip, a tool such as a spanner is required at the time of extraction, and there is a possibility that the probe may be damaged by the tool or the check claw.

[0006] As described above, the conventional mounting structure remains unsatisfactory in terms of probe attachment / detachment, cost, and reliability.

An object of the present invention is to provide a mounting structure capable of eliminating these dissatisfactions.

[0008]

In the present invention, in order to solve the above problems, a non-circular through hole is provided in the back plate of the brake pad. Then, a probe having a head portion having a size that cannot pass through the hole, a body portion that passes through the hole, and a groove portion provided on the outer periphery of the body portion that penetrates the hole is inserted into the through hole. Further, the body of the probe is shaped so as to be fitted into the through hole in a non-circular shape so as to prevent the probe from rotating, and further, the snap ring is locked to the groove portion passing through the through hole to prevent the probe from coming off.

It should be noted that the snap ring may be provided with a locking piece for preventing rotation and a spring force generating portion for preventing displacement of the probe described in the embodiments.

[0010]

Since the probe is directly inserted into the through hole of the pad back plate and prevented from coming off by the snap ring, the structure is simplified and it is advantageous in cost.

Further, since the probe can be inserted into and removed from the through hole without resistance by removing the snap ring, the probe can be easily attached and detached without exerting an unreasonable force.

[0012]

1 to 5 show a first embodiment. As shown in FIG. 1, the back plate 2 of the pad 1 is provided with a through hole 4 composed of two parallel surfaces and two arcuate surfaces that are concentrically located and face each other. 3 is a pad friction material,
The hole 4 is at a position avoiding this friction material. The size of the through hole 4 is related to the relationship of a> b.

The probe 5 is inserted into the through hole 4 and is prevented from coming off by the snap ring 6.

The probe 5 has a head portion 5a having a size that cannot pass through the through hole 4, a body portion 5b that passes through the hole 4, and a groove portion 5c into which the snap ring 6 is fitted.

The head portion 5a is provided on the rear side where the electric wire 7 is drawn out because it is complicated because the electric wire 7 for detection needs to pass through the hole 4 first when it is on the detection end side.

The body 5b has a cross-sectional shape similar to that of the hole 4 and is slightly smaller than the hole 4. Dimension d between arc surfaces
Is larger than the dimension b between the planes of the holes, and therefore can be inserted into and removed from the hole 4 without resistance, and after insertion, it is restricted by the plane of the hole 4 and is prevented from rotating.

As shown in FIG. 2, the groove portion 5c is provided on the outer periphery of the body portion that penetrates the hole 4. With this configuration, the head and the snap ring prevent the probe from coming off the hole.

The snap ring 6 has a wide entrance width w as shown in FIG. 5 so that the snap ring 6 can be fitted into the groove 5c by pushing with a finger. In this case, if w> c, the snap ring may fall off spontaneously when it rotates. Therefore, the illustrated snap ring 6 is provided with an abutting piece 6b which is continuous with the fitting portion 6a with the groove portion. Is locked to the outer peripheral surface of the back plate 2 to prevent rotation.

The contact piece 6b can be used to determine whether the snap ring is assembled or not depending on whether it is in contact with the outer surface of the back plate, and the snap ring can be easily installed by inserting a screwdriver or the like between the contact plate 6b and the back plate. Since it can be omitted, it is desirable to provide it even if the condition of w> c is not satisfied. However, when the purpose is only to prevent the probe from coming off, a snap ring 16 having a narrow inlet and no contact piece is sufficient as shown in FIG. This is advantageous if cost is important.

It is not essential that the body of the probe 5 be similar to the hole 4. The point is that the hole 4 may have a non-circular fitting shape. For example, even if the hole 4 and the probe body are elliptical, the purpose of preventing rotation is achieved. In this case, both the hole and the probe have good workability, and the edges of the surface of the probe body are eliminated, so that damage to the probe is less likely to occur.

FIG. 7 shows still another embodiment of the snap ring. As shown in the figure, the snap ring 26 is provided with a locking piece 26b that engages with the outer periphery of the back plate 2 and is retained. Further, a spring force generating portion 26c is provided between the locking piece and the fitting portion 26a for the groove portion so as to contact the end face of the back plate. In this snap ring, the distance h ₁ of the fitting portion 26a from the end face of the back plate is made larger than the protrusion amount h ₂ of the groove 5c from the end face of the back plate, and the fitting portion 26a moves in the axial direction of the hole in the use state. Displace. Therefore, the spring force generating portion 26c elastically deforms to generate a spring force, and the force causes the probe head to come into pressure contact with one surface of the back plate. Since this type of detector detects the current limit and the like caused by the electric wire 7 coming into contact with the disk, it knows the wear limit, so that the axial displacement due to the machining error of the probe is applied by applying the spring force as described above. It can be said that the elimination is an effective measure in terms of detection accuracy, and furthermore, the behavior of the probe due to the axial play between the probe and the back plate can be eliminated,
It is possible to prevent damage to the probe head due to vibration.

[0022]

As described above, according to the present invention, the body is directly fitted into the through hole provided in the back plate of the pad in a non-circular shape to prevent the probe from rotating, and the probe head and the snap ring are used to form the hole. Since it is prevented from coming off, the parts cost is small, no special assembly equipment is required, and it is advantageous in terms of manufacturing and cost.

Further, since the manufacture is simple and the snap ring can be removed to freely attach / detach, replacement of the probe in case of a failure becomes easy.

Furthermore, since an unreasonable force is not applied to the probe at the time of attachment / detachment, the probe is excellent in protection and the reliability of the detector is easily maintained.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a side view showing a locked state of the snap ring.

FIG. 4 is a perspective view of a probe.

FIG. 5 is a perspective view of a snap ring.

FIG. 6 is a perspective view showing another form of the snap ring.

FIG. 7 is a side view showing another state of the snap ring in use.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pad 2 Back plate 3 Friction material 4 Through hole 5 Probe 5a Head part 5b Body part 5c Groove part 6, 16, 26 Snap ring 6a, 26a Fitting part 6b Abutting piece 26b Engaging piece 26c Spring force generating part 7 Electric wire

Claims (3)

[Scope of utility model registration request] 1. A non-circular through hole is provided on a back plate of a brake pad, and the through hole has a head portion of a size that cannot pass through the hole, a body portion that passes through the hole, and an outer periphery of the body portion that penetrates the hole. Insert the probe with the groove to be provided, make the body part non-circular fit into the through hole to prevent the probe from rotating, and remove the probe by locking the snap ring in the groove that has passed through the through hole. Brake pad wear detector mounting structure to stop. 2. The mounting structure for a brake pad wear detector according to claim 1, wherein the snap ring is provided with an abutting piece that comes into contact with the outer peripheral surface of the back plate. 3. The snap ring is provided with a locking piece that engages with the outer peripheral portion of the back plate, and the distance of separation of the snap ring fitting portion from the back plate with respect to the groove is determined by the distance from the back plate to the groove. The mounting structure for the brake pad wear detector according to claim 1, further comprising a spring force generating portion that elastically deforms between the locking portion and the locking piece.