JPH04302722A - Pad abrasion warning device - Google Patents

Abstract

PURPOSE:To provide an abrasion warning sensor of a brake pad unnecessary to be replaced even when the brake pad is displaced. CONSTITUTION:In a pad abrasion warning device which gives a warning of the abrasion limit of a brake pad electrically, an abrasion warning sensor 1 which furnishes a back plate welded integrally to the brake pad, a plate 4 fixed to a mounting 30 and to push the above brake plate when the above brake pad reaches the abrasion limit, and a switching means 5 to be turned ON by moving the above plate 4 pushed by the back plate, is provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for electrically detecting the wear limit of brake pads in a disc brake and issuing an alarm.

0002

[Prior Art] A conventional technique of this type is, for example, Japanese Patent Publication No. 52-8950, in which notches and through holes are formed in each of the brake pad and the back plate that is integrally bonded to the brake pad. A sensor is inserted into the notch and through hole to detect the wear limit of the brake pad.

0003

[Problems to be Solved by the Invention] However, in the prior art as described above, the sensor is not removable, and when replacing the brake pads, even an unused sensor must be replaced. Even if it were removed and reused, it would be extremely unreasonable due to cost and other considerations.

[0004] Therefore, it is conceivable to install a removable sensor, but one is to detect the wear limit of the brake pads by disconnection of the conductor, and the other is to detect the limit of wear of the brake pads when the conductor is disconnected. In the former case, once the wear limit of the brake pads has been detected, the conductor is cut, making it impossible to reuse the sensor. In the latter case, the length of the conductor changes due to friction between the conductor and the disc rotor, and if you try to reuse it as is, it will not be possible to accurately detect the wear limit of the brake pads, and the harness will be damaged. If the brake pad is missing, there is a problem in that even if the brake pad reaches its wear limit and the conductor comes into contact with the disc rotor, the brake pad's wear limit cannot be detected.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the need for replacing a wear warning sensor even when replacing brake pads, and to improve reliability.

[0006]

[Structure of the invention]

[0007]

[Means for Solving the Problems] The technical means taken by the present invention to solve the above-mentioned technical problem is to provide a pad wear warning device that electrically warns the wear limit of brake pads by bonding them together with the brake pads. a back plate that is fixed to a mounting that is integrally fixed to the vehicle body, and a plate that presses the back plate when the brake pad reaches its wear limit; and a plate that presses the back plate when the brake pad reaches its wear limit. and a wear warning sensor having a switch means that is turned on when the wear warning sensor is moved.

[0008]

[Operation] The above technical means operates as follows. The wear limit of the brake pads can be detected by the back plate pressing the plate and coming into contact with the switch means.

Furthermore, due to this effect, there is no need to replace the wear warning sensor when replacing the brake pads, and since the sensor wear warning sensor is installed on the mounting, when the wear warning sensor is installed on the brake pads and back plate, it is not necessary to replace the wear warning sensor. In comparison, since the heat and vibration are small, the reliability of the wear warning sensor itself is improved.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments to which the present invention is applied will be described in detail below with reference to the accompanying drawings.

In FIG. 1, a disc brake caliper 20 includes a disc rotor 21 (see FIG. 4) that rotates integrally with a wheel (not shown) by hydraulic pressure, an inner brake pad 22 (see FIG. 4), and an outer brake pad 23 (see FIG. 4).
The wear warning sensor 1 electrically detects the wear limit of the inner brake pad 22 or the outer brake pad 23 and issues an alarm. Now, a case will be described in which the wear limit of the inner brake pad 22 is detected.

In FIG. 2, which shows a cross-sectional view taken along the line A-A shown in FIG. 1, the wear warning sensor 1 is formed on a mounting 30 fixed to a suspension (not shown). , is fitted into a stepped hole 31 having a large diameter portion 31a and a small diameter portion 31b. The wear warning sensor 1 includes a body 2 made of thermosetting resin and has a large diameter portion 2a and a small diameter portion 2b that fit into the large diameter portion 31a and the small diameter portion 31b of the stepped hole 31, respectively. A harness 3 is embedded inside the body 2. A plate 4 extending from the body 2 and a hemispherical switch portion 5 protruding from the body 2 are connected to the harness 3 by soldering. The plate 4 and the switch portion 5 may be made of conductive materials such as copper.

The wear warning sensor 1 detects the wear limit of the inner brake pad 22 when the plate 4 is pressed against the inner back plate 24 and comes into contact with the switch portion 5. This allows the wear limit to be set arbitrarily.

Next, an explanation will be given of the operation when the wear limit of the inner brake pad 22 is detected when the inner brake pad 22 is worn down due to friction with the disc rotor 21 during the braking operation.

In FIG. 4, when the driver depresses the brake pedal (not shown), a booster (not shown) is activated.
The increased hydraulic pressure is applied to the master cylinder (not shown).
The piston 26 slides toward the disc rotor 21, and the inner brake pad 22, which is in contact with the tip of the piston 26, moves toward the disc rotor 21 and comes into contact with the disc rotor 21. , which performs braking action.

Furthermore, the outer brake pad 23 has a cylinder portion 25 that moves toward the inner side via the disc brake caliper 20 due to the reaction force of the hydraulic pressure, and comes into contact with the disc rotor 21 side in the same way as the inner brake pad 22. ,
Perform braking action.

When the degree of wear of the inner brake pad 22 reaches the wear limit, the driver further depresses the brake pedal (not shown), and the inner back plate 24
Disc rotor 2 integrated with inner brake pad 22
When sliding to the 1 side, the inner back plate 24 presses the plate 4. As a result, the plate 4 comes into contact with the switch portion 5 (see FIG. 3), thereby detecting the wear limit of the inner brake pad 22.

In the present invention, the wear warning sensor 1 is installed on the inner mounting 30, but it may also be installed on the outer side.

Further, in the above embodiment, a separate circuit is provided, and once the wear limit of the inner brake pad 22 or the outer brake pad 23 is detected, the inner brake pad 22 or the outer brake pad 23 is removed by that circuit. It is possible to keep a warning of the wear limit of 23.

[0020]

[Effects of the Invention] According to the present invention, the wear limit of the brake pads can be detected by the back plate pressing the plate and coming into contact with the switch part, so there is no need to replace the wear warning sensor when replacing the brake pads. .

[0021] Furthermore, since the wear warning sensor is installed on the mounting, heat and vibration are smaller than when the wear warning sensor is installed on the brake pad or back plate, so the reliability of the wear warning sensor itself is improved. It also has the effect of

[Brief explanation of drawings]

FIG. 1 is a plan view of a disc brake caliper in which an embodiment of the present invention is installed.

FIG. 2 is a sectional view taken along line AA shown in FIG. 1.

FIG. 3 is an enlarged view of main parts showing the positional relationship between the back plate and the wear warning sensor when the wear warning sensor detects the wear limit of the brake pad.

FIG. 4 is a sectional view of a disc brake caliper in which this embodiment of the present invention is installed.

[Explanation of symbols]

1... Wear warning sensor 4...Plate 5...Switch part 22...Inner brake pad 24...Inner back plate 30...Mounting

Claims (1)

[Claims] 1. A pad wear warning device that electrically warns the wear limit of brake pads, wherein the brake pads are fixed to a back plate that is integrally bonded to the brake pads and a mounting that is integrally fixed to the vehicle body. A pad wear warning sensor comprising: a plate against which the back plate is pressed when the wear limit is reached; and a switch means that is turned on when the plate moves while being pressed by the back plate. Device.