JPH11325138A - Wear detection sensor for vehicle brakes - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention relates to a sensor structure using a commercially available harness that does not require special processing. It is an object of the present invention to provide a vehicle brake wear detection sensor that can be attached. A wear detection sensor according to the present invention forms a sensor section (14) formed by connecting leads (11a) of a pair of lead wires (11) at one end of a harness (10) where a pair of lead wires (11) are bundled. A structure in which the sensor unit 14 is positioned and fixed by sandwiching the sensor unit 14 between the pair of cover members 15a is employed. And lead wires 11
Therefore, even if the total length of the lead wires is long, it is not necessary to bundle the assembled lead wires 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake wear detection sensor for detecting a wear limit of a friction material used in a vehicle braking device.

[0002]

2. Description of the Related Art In a braking device mounted on an automobile (vehicle), for example, a disc brake device, a brake pad (brake friction material) is worn and a remaining thickness is reduced so as to secure a stable braking effect. When the wear limit is approached, an indicator device is provided to inform the driver that the brake pad is worn, that is, it is time to replace the brake pad.

This indicator device has a structure in which a wear detection sensor is used to electrically detect a wear limit of a brake pad and inform a driver of replacement time by turning on an indicator lamp.

In a wear detection sensor used in an indicator device, a conductor sensor using a metal piece is formed at the tip of a pair of lead wires, and the sensor is molded by a resin member. A structure in which a holder that can be incorporated into a brake pad is formed is used. Then, by fixing the holder to the back metal of the brake pad and projecting a sensor built in the holder from the pad side by a predetermined amount, when the brake pad wears to near the wear limit,
The sensor portion and the holder are worn, and the abrasion proceeds to the disconnection of the sensor portion, and the time for replacing the brake pad can be detected from the disconnection.

[0005]

Incidentally, it is desired that the wear detecting sensor has high reliability at low cost. For this purpose, a simple structure is required for the wear detection sensor.

However, a structure in which a resin piece is formed around a metal piece, such as the above-mentioned wear detection sensor, to be used as a holder requires special processing. Can not do.

For this reason, a wear detection sensor employing resin molding is expensive in cost. Therefore, Japanese Utility Model Publication No. 2-19638,
As disclosed in Japanese Patent No. 32873, there has been proposed a wear detection sensor in which a sensor portion made of a conductor is incorporated in a holder without using a resin molding process which is difficult in terms of cost.

In the former (Japanese Utility Model Publication No. 2-19638), a holder is formed by a member having a radially penetrating insertion hole at the tip end and a pair of grooves extending in the axial direction continuous with the insertion hole on the outer peripheral portion. Then, one lead wire is inserted into the insertion hole, and the inserted lead wires on both sides are accommodated in the groove.
This is a structure in which a sensor section is formed inside the holder.

In the latter case (JP-A-9-32873), a holder is formed by a member having a U-shaped groove which is continuous from the front end to the outer periphery on the outer surface, and one lead wire is formed into a loop. Each of the loop portions is fitted into a groove of the holder to form a sensor portion inside the holder.

However, none of them is suitable for a wear detection sensor having a long lead wire. To explain this point, the wear detection sensor normally leads the lead wire continuously from the disc brake attached to the front axle to the vehicle body side so that splashes from tires and road surfaces do not enter the inside of the connector. It is wired and connected to a notification circuit using an indicator lamp on the body frame side with a connector. The middle lead wire allows the vertical stroke of the suspension device and the steering area of the front wheels.

At this time, the total length of the lead wire extending from the sensor portion is short in a passenger car because the lower surface of the body frame is close to the ground, but a vehicle such as a truck in which the lower surface of the body frame is located far away from the ground. In this case, a long lead wire having a considerably long dimension is required (for example, about 1 m).

In the case of a wear detecting sensor having a long lead wire, a pair of lead wires is used to secure the rigidity of the portion from the disc brake to the body frame and to prevent the other portions from being affected. Is required to be bundled.

However, the former structure is a structure in which a lead wire is inserted through an insertion hole penetrating in the radial direction of the holder, so that there is no problem in the case of a short lead wire. An operation of bundling the pair of lead wires that have been inserted is required, and the man-hour and cost spent for assembling the wear detection sensor to the vehicle may be increased.

Unlike the former structure, the latter sensor structure has a structure in which a lead wire is fitted in a U-shaped groove, and therefore, the positioning of the inverted lead wire portion serving as the sensor unit tends to be unstable. For this reason, if the lead wire is short, the lead wire is long, and the location where the lead wire is to be wired, the twisted pair of lead wires or a special slidable tube must be used separately. Using fixing means such as fixing the sensor unit by inserting
It is necessary to position the sensor unit, and as in the former case, the man-hour and cost for assembling the wear detection sensor to the vehicle also increase.

The present invention has been made in view of the above circumstances, and has as its object the structure of a sensor unit using a commercially available harness that does not use special processing, regardless of the length of the lead wire. Another object of the present invention is to provide a vehicle brake wear detection sensor that can be mounted on a vehicle without increasing the number of steps and costs.

[0016]

According to a first aspect of the present invention, there is provided a wear detecting sensor according to the first aspect, wherein a pair of lead wires are connected at one end of a harness in which the pair of lead wires are bundled. Is formed, and a structure is adopted in which the sensor portion is sandwiched and positioned by a pair of cover members,
The sensor unit is housed in the holder without any special processing such as resin molding or a separate fixing means for positioning, and even if the total length of the lead wire is long, it is assembled. This eliminates the need for subsequent work of binding lead wires.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on a first embodiment shown in FIGS. FIG. 1 shows a chassis portion of a front side of an automobile (vehicle), for example, a truck. A front axle 3 is mounted on the left end of the front axle 2 via a knuckle 4 and a spindle (not shown). A rotor 5 is also mounted on the front wheel hub, and 6 is mounted on the front wheel hub 5. Front wheel

The knuckle 4 is connected to a steering handle (not shown) in the cab via a steering mechanism (not shown). When the steering handle is operated, the front wheels 6 are steered in the vehicle width direction. It is like that.

Around the rotor 3, a caliper 9 which constitutes a disc brake device together with the rotor 3 is arranged. The caliper 9 has a pair of built-in brake pads 7 (brake wear material) arranged with the rotor 3 interposed therebetween. A hydraulic line (both not shown) connected to the brake pedal extends from a built-in piston portion (not shown) of the caliper 9 that presses the brake pad 7, and when the brake pedal is depressed, the piston is pressed by hydraulic pressure, The rotor 3 is sandwiched between the pair of brake pads 7 (application of braking force).

A wear detection sensor 8 for electrically detecting a wear limit of the brake pad 7 is provided on one brake pad 7.
Is assembled. The wear detection sensor 8 employs a structure using a commercially available honey which is a main part of the present invention. 2 and FIG. 4 show an overall view of the wear detection sensor 8, and FIG.

Describing the structure of the friction detecting sensor 8, reference numeral 10 in the figure denotes a harness. Harness 10
It is a commercially available product in which a pair of lead wires 11 is bundled with, for example, a synthetic resin material 12. As the harness, a pair of lead wires bundled by a sheath tube may be used. At one end of the harness 10, a sensor part 14 made of a conductor is formed by connecting the leads 11a derived from the tips of the two lead wires 11 to each other, for example, by a horizontal swaging ring 10a. The other end of the harness 10 is connected to a connector 13 for connecting a notification circuit.

The sensor section 14 is built in the holder 15 using a structure that does not require special processing.
Specifically, as shown in FIG. 3, the holder 15 is formed of a pair of flat cover members 15a that sandwich the harness end including the sensor unit 14 from both sides (up and down). A concave portion 16 for accommodating the entire harness end including the sensor portion 14 is formed on the inner surfaces of both cover members 15a. Further, a pair of through-holes 17a are formed in the plate surface portion of each cover member 15a, for example, in the central portion, avoiding the concave portion 16, and the sensor portion 14 is sandwiched between the two cover members 15a, and the harness end is accommodated in the concave portion 16. And then both cover members 1
5a is fastened by fastening means, for example, a screw 17 and a nut 18, so that the sensor portion 14 is provided between the cover members 15a.
Is to be pinched.

As a holder mounting means, a holder 15
A pair of protrusions 19 projecting to the left and right sides are formed on the outer periphery of the harness side of the (cover member 15a), and the snap ring fitting grooves 20 are similarly formed on the left and right sides of the tip side of the holder 15 (cover member 15a). It is formed.

As shown in FIGS. 1 and 4, the holder 15 is assembled to, for example, a back metal 7a of the brake pad 7 so as to be aligned with the brake pad 7. Specifically, the holder 15 is attached to the holder 1 from the back side of the back metal 7a.
5 through a through hole 7b formed in the back metal 7a.
After the protrusion 19 is inserted until the opening edge of the through hole 7b abuts, the snap ring fitting groove 2 is inserted from the front side of the back metal 7a.
By fitting the snap ring 21 at 0, the sensor section 14 is positioned at a point corresponding to the wear limit of the brake pad 7.

The other end of the honey 10 is continuously wired from the caliper 9 to the frame 1. Then, on the vehicle body side (not shown), the connector 13 at the honeys end and the connector 22 on the notification circuit (both not shown) employing, for example, an indicator lamp are connected, and water from tires or road surface is sprayed inside the connector. The upper and lower strokes of the suspension device and the steering area of the front wheels 6 are escaped in the middle harness portion while preventing the vehicle from entering the vehicle. Reference numeral 10b denotes a fixture for fixing the harness 10.

The wear detecting sensor 8 thus assembled
When the brake pad 7 is worn to near the wear limit, the conductor (lead 11a, caulking ring 1)
0a) and the wear of the holder 15, and further the wear progresses to the disconnection of the conductive portion of the sensor portion 14, and the detection of this disconnection turns on the indicator lamp, prompting the driver to replace the brake pad 7.

According to the structure of the wear detecting sensor 8, since the structure of the holder 15 is a cover type, that is, a structure in which the sensor portion 14 is sandwiched between a pair of cover members 15a, a special processing that increases costs and man-hours is required. That is, no resin molding is required, and the cost can be reduced.

In addition, the sensor section 14 includes a cover member 15
Since the positioning is reliably performed and fixed inside the holder 15 by the holding by the “a”, a special process and parts for separately positioning the sensor unit 14 are unnecessary, and the cost can be reduced from this point as well.

In addition, the wear detecting sensor 8 simultaneously forms the sensor portion 14 and the harness 10 connected to the sensor portion 14 by directly connecting the leads 11a of the bundled lead wires 11, so that a commercially available harness is used. Of course, even when a long lead wire 11 is used, such as when assembling to a truck as in the present embodiment, work such as bundling the lead wire 11 is performed after the assembly of the sensor unit 14 is completed. It is not necessary, and the man-hour and cost spent for assembling the wear detection sensor 8 can be reduced. In other words, regardless of the length of the lead wire 11, the wear detection sensor 8 can be assembled into an automobile (vehicle) without unnecessary man-hours and costs.

Therefore, it is possible to provide the wear detecting sensor 8 which is excellent in cost and further in handling. FIG. 5 shows a second embodiment of the present invention.
An embodiment will be described. In the present embodiment, the leads 11a derived from the tips of the two lead wires 11 are
0 to form a sensor portion 14 made of a conductor.

The same effect as that of the first embodiment can be obtained by such a caulking structure of the lead 11a. However, FIG.
In FIG. 7, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the above embodiment, the pair of lead wires 11 bundled using the synthetic resin material 12 is used. However, the present invention is not limited to this, and the pair of lead wires 11 may be bundled using other means. You may.

Further, in the above-described embodiment, an example was given in which the wear detection sensor of the present invention was assembled to the disc brake device of the truck. However, the present invention is not limited to this, and the wear detection sensor is applied to other vehicles and other braking devices. May be.

[0034]

As described above, according to the first aspect of the present invention, a structure in which a sensor portion formed by connecting a pair of bundled lead wires is sandwiched and positioned by a pair of cover members is provided. Since the adoption is employed, the sensor unit can be housed in the holder unit without any positional shift without using special processing such as resin molding or fixing means for positioning separately, and with an inexpensive structure. Moreover, since the pair of bundled lead wires is used as a harness, commercially available lead wires can be used, and even when the total length of the lead wires is long, there is no need to bundle the assembled lead wires.

Therefore, a wear detection sensor which can be mounted on a vehicle without reducing man-hours and costs irrespective of the length of the lead wire, and which is excellent in cost and handleability, can be realized. Can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing a wear detection sensor according to a first embodiment of the present invention, together with a disc brake device to which the sensor is assembled.

FIG. 2 is a perspective view for explaining the overall structure of the wear detection sensor.

FIG. 3 is an exploded perspective view of the wear detection device.

FIG. 4 is a cross-sectional view of the wear detection sensor along the line AA in FIG. 2;

FIG. 5 is a cross-sectional view of a wear detection sensor according to a second embodiment of the present invention.

[Explanation of symbols]

 8: Wear detection sensor 10: Harness 10a: Caulking ring 11: Lead wire 12: Synthetic resin member 14: Sensor part 15: Holder 15a: Cover member.

Claims (1)

[Claims] 1. A wear detection sensor for a vehicle brake, wherein a sensor portion made of a conductor is built in a holder and the wear is detected by disconnection of the sensor portion due to wear of a friction material for a brake, and a pair of lead wires are bundled. The sensor unit is formed by connecting the pair of lead wires at one end side of the harness provided, the holder is formed by a pair of cover members, and the sensor unit is sandwiched by the pair of cover members and the holder is formed. A wear detection sensor for a vehicle brake, wherein the sensor is positioned within the vehicle.