JPS6179103A - Temperature and abrasion degree sensor for brake - Google Patents

Abstract

PURPOSE:To detect the temperature of brake liquid and the degree of abrasion of a brake lining by providing a temperature sensing element for brake temperature detection and a movable body which presses the piston in a brake cylinder, and varying electric continuity. CONSTITUTION:The temperature sensing element 12 which detects an abnormal rise in the temperature of the brake liquid 5 and the movable body 13 which presses the piston 4 in the cylinder 3 are provided in the cylinder 3, and when the piston 4 moves owing to the abrasion of brake linings 1 and 1a, the movable body 13 falls off the piston 4. Then, the electric continuity between the movable body 13 and a case which contains the temperature sensing element 12 and movable body 12 varies according to the movement of the movable body 13 through a conductive seal material 16 provided on the slide surface between the case 14 and movable body 13, which is utilized to detect the abrasion limits of the linings 1 and 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used in brake safety devices for automobiles, railway vehicles, etc., and is used to detect abnormal temperature of brake fluid and detect wear limit of brake lining. This relates to a degree sensor.

Conventional Structure and Problems Therein FIG. 1 shows a cross-sectional view of a conventional disc brake equipped with a brake lining wear limit sensor, and FIG. 2 shows an enlarged cross-sectional view of the vicinity of this sensor. In Fig. 1, 1.1a is the brake lining, 2.2a is the back metal, and the piston 4 in the cylinder 3 is connected to the brake fluid 5.
Due to the movement by the hydraulic pressure, the girotaro is sandwiched between the brake linings 1 and 1a from both sides, and a braking action is produced by the frictional force generated at the contact surfaces. Therefore, if the sensor 7 is installed in the brake lining 1 (or 1a), when the brake lining 1 wears out due to friction with the brake lining 1 (or 1a), the tip of the sensor 7 will also be scraped off, so this can be utilized. Thus, the wear limit of the brake lining 1 can be detected.

Next, the details of the wear limit detection of brake lining 1 will be explained in the second section.
This will be explained according to the diagram. In Figure 2, 8 is a metal wire, 9
1 is a case, and 10 is an external lead wire, which constitutes a sensor 7. Since the sensor 7 is embedded in the brake lining 1 via the metal backing 2, when the brake lining 1 wears out and is scraped from the initial position A to the limit position B,
The sensor 7 is also scraped together and the metal wire 8 is broken. At this time, the resistance of the sensor 7 seen from the external drawer #10 changes from zero to infinity, and the wear limit of the brake lining 1 can be detected.

However, this sensor only detects the wear limit of the brake lining and has the disadvantage that it is disposable.

On the other hand, from the safety aspect of the brake system, it is necessary to prevent paper lock (a condition in which the brake fluid becomes ineffective due to air bubbles forming inside due to abnormal temperature rise) that occurs when the brakes are used continuously, especially on downhill slopes. Therefore, there is a strong demand for a sensor that can also detect abnormal temperature rises in brake fluid.

Purpose of the Invention The present invention provides a brake system that has both the functions of detecting the wear limit of brake linings and detecting abnormal temperature rises of brake fluid.
The present invention aims to provide a wear rate sensor.

Structure of the Invention In order to achieve the above object, the structure of the present invention includes a heat-sensitive element for detecting an abnormal temperature rise of brake fluid, a movable body that presses a piston in a brake cylinder, and a movable body that presses a piston in a brake cylinder. The movable body is structured to fall off the piston when the piston moves due to wear, and a conductive sealing material is provided on a sliding surface between the movable body and a case that houses the heat-sensitive element and the movable body. The brake lining is configured to include a mechanism that also detects the wear limit of the brake lining by utilizing the fact that electrical continuity between the movable body and the case changes in accordance with the movement of the movable body. .

Explanation of an actual winding example FIG. 3 shows an actual winding example of the present invention. In FIG. 3, reference numeral 11 denotes a sensor according to the present invention, which is installed in the cylinder 3 at a position where it comes into contact with the brake fluid 6 and the piston 4.

Next, FIG. 4, which is an enlarged sectional view of the sensor according to the present invention, will be described. In FIG. 4, one lead wire of a heat-sensitive element 12 (for example, S + Mister) that detects the temperature of the brake fluid 5 is attached to the inner bottom surface of the movable body 13, and the other lead wire is insulated on the top surface of the movable body 13. Ushita is attached to the electrical plate 18 attached via the plate 17. The electrode plate 18 is connected to an external lead terminal 22 via a compression coil spring 19, and the external lead terminal 22 is insulated from a metal case 24 by two insulators 20, 23 and an O-ring 21.
Fixed. Further, a part of the outer peripheral surface of the movable body 13 is composed of an insulating cylinder 15 having the same outer diameter as the movable body 13, and a conductive sealing material 16 provided on the sliding surface between the movable body 13 and the case 24 is normally The insulating tube 15 is arranged so as to be in direct contact with the outer circumferential surface of the movable body 13, and to be in contact with the outer circumferential surface of the insulating tube 16 when the brake lining is worn out. Here, the conductive sealing material 16 not only turns on and off electrical continuity between the case 24 and the movable body 13, but also allows the brake fluid 6 to
Preventing it from entering inside. Further, even if the brake fluid 5 enters the inside of the case 24, a seal is provided by the O-ring 20 so that the brake fluid 5 does not leak out to the outside of the sensor.

Next, the operating principle will be explained. Sensor 1 according to the present invention
1, the tip of the movable body 13 contacts the piston 4 in the cylinder 3, and the movable body 13 is lifted by the piston 4, so that the conductive sealing material 16 directly contacts the outer peripheral surface of the movable body 13. Therefore, since the heat-sensitive element 12 is connected in series between the case 24 and the external lead-out terminal 22, an abnormal temperature rise in the brake fluid 6 can be detected. On the other hand, as the brake linings 1 and 1a wear out, the piston 4 moves to the left, and when it reaches the wear limit position, it enters the state shown in FIG. 4.

That is, the movable body 13 slips down from the side surface of the piston 4, the conductive sealing material 16 comes into contact with the insulating cylinder 16 located on the upper outer peripheral surface of the movable body 13, and the case 24 and the movable body 13 are in an electrically open state. become. Thereby, the wear limit of the brake lining 1.1a can be detected.

Effects of the Invention As mentioned above, according to the temperature and wear degree sensor of the present invention,
A single sensor has both the functions of detecting the temperature of the brake fluid and the degree of wear of the brake lining, and has the advantage that it is not disposable and can be used semi-permanently.

It also has a disconnection detection function because it is electrically opened only when wear of the brake lining is detected.

Furthermore, since the conductive sealing material has both the on/off function of electrical conduction and the sealing function, the structure is simple and can be manufactured at low cost.

[Brief explanation of drawings]

1 and 2 are configuration diagrams showing a conventional sensor for detecting the wear limit of a brake lining, FIG. 3 is a configuration diagram showing the mounting state of a brake temperature and wear degree sensor according to the present invention, and FIG. The figure is a sectional view showing the internal configuration of the sensor. 1. Brake lining for 1a, 3...
Cylinder, 4... Piston, 6... Brake fluid, 11... Sensor, 12...
Heat-sensitive element, 13...Movable body, 16...
Conductive sealing material, 24... Case. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 AB/3

Claims (1)

[Claims] A heat-sensitive element that detects the temperature of brake fluid, a movable body that presses a piston that moves in response to wear of the brake lining, and a case that houses the heat-sensitive element and the movable body, the movable body and the case A brake temperature and wear sensor that uses conductive sealing material on the sliding surface.