JPH04237659A - Installation structure for wheel speed sensor - Google Patents

Abstract

PURPOSE:To prevent the deterioration of function due to the adhesion of mud or generation of rust by installing a wheel speed sensor in compact form on a rigid axle equipped with a drum brake. CONSTITUTION:As for a rigid axle 20 equipped with a hub casing 1 for supporting the axle 2 on a car body side through a bearing on the outer periphery of the axle 2, a sensor rotor 30 for detecting the wheel speed is fixed on the axle 2 contiguously to the bearing 10 in the hub casing 1, and a sensor is installed in the hub casing 1 in proximity to the outer periphery of the sensor rotor 30.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for a wheel speed sensor, and more particularly to a mounting structure for a wheel speed detection sensor for an anti-lock (skid) brake system in a drum brake.

0002

[Prior Art and Problems] Conventionally, wheel speed sensors for anti-lock brake systems have been developed as a means to prevent brake locks at high speeds, and have been put to practical use, particularly in disc brakes that have high braking and heat dissipation effects at high speeds.

On the other hand, drum brakes are still difficult to abandon due to their high braking load, self-boosting effect, low-speed braking force, parking braking force, etc., and are still used on all wheels and wheels of trucks, buses, commercial vehicles, etc. Used in the rear axles of passenger cars.

[0004] Unlike disc brakes, this drum brake has one aspect in which it is difficult to arrange a sensor rotor and a sensor on each axle due to space limitations. This is because with disc brakes, there is space within the wheel rim between the disc and the inner edge of the hub, making it relatively easy to install the sensor rotor for the anti-lock brake system, whereas with drum brakes, that space is limited. This is because all of the space is taken up by the brake drum and back plate.

[0005] Although there are examples in which the wheel cylinder, brake shoe, parking brake link structure, etc. inside the drum brake are rearranged to create space inside the drum brake and a wheel speed sensor is installed, the structure is complicated and special parts are required. This was not a desirable method because it required the use of a drum brake and the functions of the drum brake tended to be limited.

[0006] Therefore, the inventor of the present invention came up with the idea of installing a wheel speed sensor using the slight dead space of a rigid axle type drive shaft, which is often equipped with a drum brake, and as a result of intensive study, the present invention was arrived at. .

[0007]

OBJECTS OF THE INVENTION An object of the present invention is to compactly attach a wheel speed sensor to a rigid axle type drive shaft, which is often equipped with a drum brake, by making slight modifications without making any fundamental design changes.

Another object of the present invention is to provide a mounting structure for a wheel speed sensor that is built into a hub casing and is free from functional deterioration due to dirt due to adhesion of mud or rust.

[0009]

According to the present invention, in a wheel speed sensor mounting structure in which a sensor rotor is fixed to the outer periphery of an axle and the sensor is mounted close to the outer periphery of the sensor rotor, the sensor rotor is attached to the axle adjacent to a bearing in a hub casing. A mounting structure for a wheel speed sensor is provided, characterized in that the sensor is mounted on a hub casing.

The present invention will be explained in detail below using examples.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan sectional view of an embodiment of the present invention.

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

1 and 2, 1 is a hub casing, 2 is an axle, 3 is an axle hub, 4 is a wheel, 5 is a brake drum, 8 is a back plate, 10 is a ball bearing, 11 is a bearing retainer, and 20 is a 30 is a sensor rotor, 31 is a sensor, and 32 is a sensor cord.

The gear-like sensor rotor 30 has a bearing 11
is fixed to the axle 2 adjacent to the axle 2. An oil seal 20 is fixed to the hub casing 1 adjacent to the sensor rotor 30 so that its lip 20A contacts the annular portion 30A of the sensor rotor 30, thereby preventing gear oil from flowing in from the differential gear.

Naturally, the inner race of the bearing 11 is fixed to the axle 2, and the outer race is fixed to the hub casing, and the bearing 11 is provided with a bearing retainer 11 on at least one side of the sensor rotor for bearing lubrication. This prevents grease and the like from contaminating the sensor rotor 30.

The wheel speed sensor 31 is normally a magnetic sensor, which is also fixed to the hub casing 1, with the tip of the sensor provided close to the outer periphery of the sensor rotor 30. A pulse signal (alternating current) corresponding to the rotational speed of the axle 2 obtained by the sensor 31 is transmitted to the CPU near the engine room via the sensor cord 32.

Originally, the bearings of the rigid axle type drive shaft are lubricated by the gear oil stored in the differential gear (including the final reduction gear), so if the oil seal 20 is not present, the sensor rotor 30 and This is because the sensor 31 may be contaminated with gear oil, making it impossible to accurately measure the wheel speed. For the same reason, a bearing retainer 11 is provided on at least one side (or both sides) of the bearing 11, which is lubricated with grease, on the sensor rotor side to prevent the sensor rotor 30 and the sensor 31 from being contaminated by grease.

The suspension system of the rigid axle according to the present invention is not limited to two parallel leaf springs in the front and rear, but four to four coil springs.
5 multi-link type etc. are also included.

The present invention is not limited to rigid axles, but can also be applied to independent suspensions. In that case, the inner oil seal 20 of the above embodiment can be omitted.

As shown in FIG. 3 (a cross-sectional plan view of another example of the concept), the inner tip 5A of the brake drum 5 itself is processed with a gear (attached at the time of casting, machined later, or formed with another gear-shaped ring). ) and attach the back plate 8.
If the wheel speed sensor 31 is fixed to the outer peripheral portion 8A of the wheel, the diameter of the sensor rotor becomes maximum without providing a sensor rotor, and wheel speed can be measured with high accuracy even at low speeds.

[0021]

[Effects of the Invention] By carrying out the present invention, all of the above objects are achieved.

In other words, the wheel speed sensor can be mounted compactly within the hub casing. Therefore, there is an effect that functional deterioration due to dirt and rust can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a plan sectional view of an embodiment of the present invention.

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

FIG. 3 is a plan cross-sectional view of another conceptual example.

[Explanation of symbols]

1 Hub casing 2 Axle 4 Wheel 5 Brake drum 8 Back plate 10 Bearing 11 Bearing retainer 20 Oil seal 30 Sensor rotor 31 Sensor

Claims (1)

[Claims] Claim 1: A wheel speed sensor mounting structure in which a sensor rotor is fixed to the outer periphery of an axle and the sensor is mounted close to the outer periphery of the sensor rotor, wherein the sensor rotor is disposed on the axle adjacent to a bearing in a hub casing; A wheel speed sensor mounting structure characterized in that the sensor is attached to a hub casing.