JPH1163053A - Wear detector for brake pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reusable wear detector for a brake pad. SOLUTION: In a recess 21 formed in a brake pad 14, the end of a pin 23 protruded from a base 12 is stored. When the brake pad 14 pushed against a rotor 10 is worn out to a specified thickness, the pin 23 is pushed by the rotor 10, slid and put in contact with a pair of detecting terminals 32, 32 to make a short circuit between both terminals 32, 32. Then, a detecting circuit is driven. In this way, the brake pad 14 is detected to be worn out to a specified thickness. If the brake pad 14 is only replaced and the pin 23 is energized by an energizing magnet 26, the flange 24 of the pin 23 is put in contact with the step surface 22A to return the pin 23 to an original position. This wear detector 20 is thus reusable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brake pad wear detecting device.

[0002]

2. Description of the Related Art For example, Japanese Utility Model Laid-Open Publication No.
A wear detecting device 1 as shown in FIGS. 4 to 6 is disclosed. The wear detecting device 1 is used for detecting wear of the brake pad 2.
Inside, the electric wire 3 is arranged to be folded back at the tip. FIG. 5 shows that the wear detecting device 1 is
It was shown that it was attached to. The brake pad 2 is fixed to the base 4, and when the brake pad 2 is worn to a predetermined position by the rotor 6, the wear detecting device 1 starts to wear at the same time. Then, when the internal electric wire 3 is finally cut, the circuit constituted by the electric wire 3 is opened, and the wear of the brake pad 2 is detected (see FIG. 6).

[0003]

However, in such a wear detecting device 1, since the irreversible change of cutting of the electric wire 3 occurs, it cannot be reused.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reusable brake pad wear detecting device.

[0005]

In order to achieve the above object, the invention of claim 1 is provided in a brake device for bringing a brake pad attached to a base into contact with a rotor, and detects wear of the brake pad. A pin receiving hole formed so as to communicate with the base and the brake pad, a pin slidably received in the pin receiving hole, and a magnetic member provided on the base and provided on the pin. An urging magnet for urging the pin from the base side to the brake pad side by magnetic force, positioning means for positioning the tip of the pin at a predetermined thickness position of the brake pad in the pin receiving hole, and a brake pad comprising: Wear to a certain thickness,
And a detecting means for detecting that the pin has been pushed by the rotor and slid to the side opposite to the urging force.

According to a second aspect of the present invention, in the brake pad wear detecting device according to the first aspect, the biasing magnet is an electromagnet.

According to a third aspect of the present invention, in the second aspect, a coil is wound around the outer peripheral surface of the cylindrical body to constitute a biasing magnet, and the hollow core of the cylindrical body is formed with a pin receiving hole. This is characterized in that a pin can be inserted into the air core portion.

[0008]

According to the first aspect of the present invention, the pin is urged by the urging magnet so as to project to a predetermined position on the brake pad side of the pin receiving hole, and the positioning means is provided. Is positioned by Then, when the brake pad is pressed against the rotor and worn down to a predetermined thickness, the pin is pushed by the rotor and slides, and the detecting means is activated. This makes it possible to detect that the brake pad has been worn down to a predetermined thickness. Then, if only the brake pad is replaced and the pin is urged by the urging magnet, the pin returns to the original position where it was positioned by the positioning means.

Thus, the brake pad wear detecting device of the present invention can be reused. Moreover, since the pin is biased by the magnetic force of the biasing magnet, there is little risk of creep deformation when the pin is biased by an elastic force such as a spring, and the pin can be used for a long time.

According to the second aspect of the present invention, since the urging magnet is an electromagnet, the magnetic force does not weaken over time unlike a permanent magnet, and can be used for a longer time.

According to the third aspect of the present invention, since the pin is disposed on the axis of the coil, the magnetic force of the coil can be efficiently applied to the magnetic material of the pin. In addition, since the pin can be inserted into the air core of the coil, the entire device becomes compact in the axial direction of the pin.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows the configuration of the brake device. In FIG.
Numeral 0 denotes a disk-shaped rotor, and a pair of bases 11 and 12 are arranged on both sides thereof, and brake pads 13 and 14 are mounted on the surfaces of the bases 11 and 12 on the rotor 10 side. Then, the base 11,
12 is shifted to the rotor 10 side, and the brake pad 1
The rotation of the rotor 10 can be stopped by the frictional forces acting between the rotors 3 and 14 pressed against the rotor 10. A wear detection device 20 to which the present invention is applied is provided on the right base 12 in FIG.

FIGS. 2 and 3 show the wear detecting device 20 in an enlarged manner. As shown in the figure, a recess 21 is formed in the mounting surface 14A of the brake pad 14 to the base 12, and the base 1 is connected to the recess 21 so as to communicate with the recess 21.
2, a through hole 22 is formed in the thickness direction. The brake pad 14 side of the through hole 22 is narrowed like a step, and a flange 24 provided on a pin 23 described below abuts the step surface 22A to position the pin 23.

The pin 23 is slidably received in a pin receiving hole 22B formed by the through hole 22 and the recess 21. The pin 23 has a cylindrical shape as a whole, and has a hemispherical surface 25 at one end thereof, and a positioning flange 24 protruding toward the hemispherical surface 25 in the outer peripheral surface. Then, with the flange 24 in contact with the step surface 22A, the tip of the hemisphere 25 is
1 is set to protrude to a position of a predetermined thickness of the brake pad 14. The pins 23 are formed of a conductive magnetic material (for example, ferrite) and are magnetized to generate a magnetic flux in the axial direction.

An urging magnet 26 is mounted on the surface of the base 12 opposite to the brake pad 14. The urging magnet 26 is a bobbin 28 on which a coil 27 is wound.
Is covered with a protective case 28A.
One of the flanges 29, 29 provided at both ends of the bobbin 28 is fixed in a state of being in contact with the base 12. The coil 27 is always excited, and a magnetic flux in a direction opposite to the direction of the magnetic flux of the pin 23 is generated in the internal space 30A of the bobbin 28.

The internal space 30A communicates with the through hole 22 of the base 12, and houses the rear end of the pin 23. The pin 23 receives a repulsive force from the urging magnet 26 and is urged toward the brake pad 14. The inner space 30 </ b> A is closed by a back wall 31 extending from the flange 29 on the side opposite to the base 12, and a pair of detection terminals 32, 32 protrudes from the back wall 31 toward the pins 23. The tip of both detection terminals 32, 32 is always
The pin 23 is separated from the pin 23 (see FIG. 2), and when the pin 23 slides, the pin 23 comes into contact with the tips of the detection terminals 32, 32 to short-circuit the detection terminals 32, 32 (see FIG. 3). ). A hood 33 is provided on the right side surface in FIG. 2 of the back wall 31, and the detection terminals 32, 32 penetrate through the back wall 31 and protrude into the hood 33 to form a connector portion 34. I have. A mating connector 3 provided on an electric wire from a detection circuit (not shown)
5 is connected.

This embodiment has the above configuration, and its operation and effects will be described below. When the brake device operates, the brake pad 14 is pressed against the rotor 10 and is worn. When the thickness of the brake pad 14 is equal to or larger than a predetermined dimension, as shown in FIG. 2, the tip of the pin 23 is farther from the rotor 10 than the pressing surface 14B of the brake pad 14, so that the pin 23 is It will not be pushed and therefore the sensing circuit will not be driven.

If the pressing surface 14B of the brake pad 14 is worn down to the tip of the pin 23, the brake pad 14 is pressed against the rotor 10 and comes into contact with it.
The tip of the pin 23 also contacts the rotor 10. Here, since the tip of the pin 23 has a hemispherical surface 25, it is slippery, and the pin 23 does not catch on the rotor 10. Further, since the pin 23 is made of a material having high hardness such as ferrite, there is no fear of abrasion.

Further, when the brake pad 14 is worn away and the degree of wear reaches the limit of use, the pin 23 projects from the brake pad 14. When the brake operation is performed in this state, as shown in FIG. 3, the pin 23 is pushed to the inside of the inner space 30 </ b> A, and the rear end of the pin 23 contacts the two detection terminals 32. Then, both detection terminals 32,
32 is switched from a non-conductive state to a conductive state, and a detection circuit (not shown) is driven. Thereby, for example, a warning lamp provided in the detection circuit is turned on. Thereafter, when the brake operation is completed, the pin 23 is urged by the urging magnet 26 to return to the original position again, and the detection terminals 32 are again in a non-conductive state. For example, a latch circuit is provided, and the warning lamp continues to light even after the brake operation is stopped.

By this lighting, it is possible to know that the brake pad 14 has been worn down to a predetermined thickness. Then, if only the brake pad 14 is replaced and the pin 23 is urged by the urging magnet 26, the pin 23 is positioned by abutment between the flange 24 and the step surface 22A, and returns to the original state.

As described above, the wear detecting device 20 of the present invention
Can be reused. In addition, since the pin 23 is biased by the magnetic force of the biasing magnet 26, there is little risk of creep deformation when the pin 23 is biased by an elastic force such as a spring, and the pin 23 can be used for a long time. Further, the present device 20 includes a coil 27
The pin 23 is arranged on the axis of
A magnetic force can be efficiently applied to the pin 23, which is a magnetic material. Moreover, the air core of the coil 27 (the inner space 30A)
Since the rear end of the pin 23 is accommodated in the pin 23, the entire device is compact in the axial direction of the pin 23.

<Other Embodiments> The present invention is not limited to the above-described embodiments, and can be implemented with, for example, the following modifications. Belongs to the range. (1) The detecting means of the above-described embodiment includes two detecting terminals 32, 3
Although it consisted of two conducting and non-conducting,
The light emitting element and the light receiving element may be provided, and the optical path may be shielded by the movement of the pin 23. In short, the detecting means only needs to be electrically turned on / off by the movement of the pin. (2) The urging magnet 26 of the present embodiment is an electromagnet, but may be a permanent magnet. However, if the urging magnet is an electromagnet as in this embodiment, the magnetic force does not weaken over time unlike a permanent magnet, and can be used for a longer period.

[Brief description of the drawings]

FIG. 1 is a side view showing a brake device according to an embodiment.

FIG. 2 is an enlarged sectional view of a wear detecting device.

FIG. 3 is an enlarged sectional view showing a state in which a wear detection mechanism is operated.

FIG. 4 is a side view of a conventional wear detection device.

FIG. 5 is an enlarged sectional view when the abrasion detecting device is attached to a base.

FIG. 6 is an enlarged sectional view when the brake pad and the wear detecting device are worn out.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Rotor 12 ... Substrate 14 ... Brake pad 20 ... Wear detecting device recess 22A ... Step surface (positioning means) 22B ... Pin accommodation hole 23 ... Pin 24 ... Flange (positioning means) 26 ... Urging magnet 27 ... Coil 28: Bobbin (cylindrical body) 30A: Internal space (air core) 32: Detection terminal (detection means)

Claims (3)

[Claims] 1. A brake device for contacting a rotor and a brake pad attached to a base for detecting wear of the brake pad, wherein the brake device is formed so as to communicate with the base and the brake pad. A pin accommodated in the pin accommodating hole, and a pin slidably accommodated in the pin accommodating hole; and a magnetic force provided between the base and the magnetic body provided on the pin. An urging magnet for urging the pin, a positioning means for positioning the tip of the pin at a predetermined thickness position of the brake pad in the pin receiving hole, and the brake pad is worn to a predetermined thickness. Detecting means for detecting that the pin has been pushed by the rotor and slid to the side opposite to the urging force. De wear detection device. 2. The brake pad wear detecting device according to claim 1, wherein said urging magnet is an electromagnet. 3. The device according to claim 2, wherein a coil is wound around an outer peripheral surface of the cylindrical body to form the biasing magnet, and an air core of the cylindrical body communicates with the pin receiving hole. A brake pad abrasion detecting device, wherein the pin can be inserted into the air core portion.