JPH0894657A - Bearing built-in rotation detector - Google Patents

Abstract

(57) [Abstract] [Purpose] Bearing built-in type rotation detection device that can suppress the strength reduction of the bearing outer ring and incorporate the electromagnetic pickup into the outer ring so as to prevent magnetic flux leakage that causes output reduction. Offer of. [Structure] Sensor mounting hole 4 provided in outer ring 12 of bearing 10
Then, a non-magnetic rigid bush 5 is press-fitted, and the body of the electromagnetic pickup 1 is inserted into the bush. In this case, the strength of the outer ring is reduced due to the processing of the hole 4, and the bush 5
The magnetic flux leakage from the electromagnetic pickup to the outer ring can be prevented by the bush 5. In addition, the bush 5 can be used to center the electromagnetic pickup to eliminate the partial compression of the O-ring 7, and the reliability of the sealing of the hole inlet can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device incorporated in a bearing and used for detecting the rotational speed of a rotating body supported by an inner ring of the bearing, for example, an axle of an automobile.

[0002]

2. Description of the Related Art An electromagnetic hip-up is faced to a sensing rotor that rotates integrally with an object whose rotational speed is to be detected, and the rotation of the rotor changes the magnetic flux coupling between the iron core and the sensing rotor that pass through the center of the electromagnetic pickup. Various electromagnetic power generation type rotation detection devices have been proposed to generate an output signal according to the rotation speed of the sensing rotor from a coil concentrically arranged on the outer circumference of the iron core. It is put to practical use as a speed sensor.

It is also considered to incorporate this detection device into a bearing for effective utilization of space.

For example, in Japanese Utility Model Laid-Open No. 1-156464, a pulsar ring is attached to the outer circumference of an inner ring of a bearing, and a sensor corresponding to the pulsar ring is attached to the outer ring so as to penetrate from the outside. It is shown that an elastic ring seals between them.

When the above-mentioned electromagnetic pickup is used as the sensor, the magnetic flux leakage that causes a decrease in output must be suppressed as much as possible, but the electromagnetic pickup incorporated in the bearing has a sufficient leakage prevention function by itself due to size regulation. Difficult to do.

For this reason, as shown in FIG. 4, the sensor mounting hole 4 provided in the outer ring 12 of the bearing 10 is made larger than the body diameter of the electromagnetic pickup 1 to be inserted into the hole so that the air gap 9 provides magnetic resistance. The method of reducing the magnetic flux leakage from the electromagnetic pickup 1 to the outer ring 12 is adopted.

[0007]

In the above magnetic flux leakage prevention measures, the diameter of the sensor mounting hole 4 is made larger than the diameter of the body of the electromagnetic pickup to be inserted into the hole in order to create the air gap 9. Is not preferable in terms of maintaining strength.

Further, since the mounting hole 4 cannot be centered, the electromagnetic pickup 1 is apt to be misaligned, and the O-ring 7 is eccentrically compressed due to the misalignment, so that the reliability of sealing the hole entrance portion is lowered.

An object of the present invention is to eliminate these problems.

[0010]

In order to solve the above problems, in the rotation detecting device of the present invention, a non-magnetic material is provided between the sensor mounting hole of the bearing outer ring and the body of the electromagnetic pickup inserted in the hole. The structure is such that a bush having a rigid body, for example, a bush made of stainless steel, brass or the like, is fixed to the hole side and intervenes.

The bushes are preferably fixed by hot or cold press-fitting.

When the inlet of the hole is sealed with a seal ring such as an O-ring, a seat groove may be provided on the inner surface of the bush and the seal ring may be housed in the groove.

[0013]

With the above-mentioned bush, a part of the sensor mounting hole is backfilled, so that the strength reduction of the outer ring can be suppressed.

Further, since the bush is a non-magnetic material, the same effect as in the case where there is an air gap can be obtained with respect to the prevention of magnetic flux leakage.

Furthermore, the bush can be used to center the electromagnetic pickup to eliminate the uneven compression of the seal ring, and the reliability of the sealing of the hole inlet portion can be improved.

The seat groove for the seal ring is effective for correctly positioning the seal ring, but if the seat groove is provided on the inner surface of the bush, the groove can be processed more easily than when it is provided on the outer ring. The seal ring diameter to be used is small.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the rotation detecting device of the present invention. In the figure, 10 is a bearing 13 between the inner ring 11 and the outer ring 12.
It is a bearing incorporating. Further, reference numeral 1 is an electromagnetic pickup which forms a rotation detecting device in combination with the sensing rotor 3.

At the center of the electromagnetic pickup 1 is provided an iron core 2 for flowing magnetic flux to the sensing rotor 3. Moreover, although a magnet, a coil for power generation, etc. are provided inside thereof, these are not shown.

The sensing rotor 3 is fixed to the outer periphery of the inner ring 11 as shown in the figure.

On the other hand, in the electromagnetic pickup 1 to be assembled to the outer ring 12, a non-magnetic bush 5 made of stainless steel or brass is press-fitted into a sensor mounting hole 4 provided in the outer ring, and the body portion on the tip side is attached to the bush. Fit and set screw 6 to outer ring 1
Fixed to 2.

Reference numeral 7 is an O-ring interposed between the electromagnetic pickup 1 and the bush 5. In the figure, the O-ring 7 is provided with a seat groove 8 which is concentric with the inner surface on the inlet side inner surface of the bush 5, and is housed therein. However, as shown in FIG. 2, it may be provided on the inner surface in the longitudinal direction. Further, as shown in FIG. 3, if the outer peripheral surface on the inlet side is provided and stored therein, the inlet portion of the press-fitting interface of the bush can also be sealed.

The bush 5 is the electromagnetic pickup 1
There is a thickness that can break the magnetic flux coupling between the body part of the outer ring and the outer ring 12. The thickness of the outer ring can be made smaller than that of the air gap 9 in FIG. 4 by reinforcing the bush 5 so that the strength of the outer ring can be suppressed to a small value.

[0023]

As described above, according to the present invention,
The air gap, which was provided between the electromagnetic pickup and the outer ring of the bearing to reduce the leakage of magnetic flux, is filled with a bush of non-magnetic material that has rigidity, so that the strength of the outer ring can be suppressed and the bearing strength can be reduced. Can be kept.

The bush may be used to center the electromagnetic pickup to enhance the sealing effect of the seal ring at the hole entrance portion, or a seat groove for the seal ring may be provided in the bush to facilitate machining of the groove. it can.

[Brief description of drawings]

FIG. 1A is a cross-sectional view showing an example of a rotation detection device of the present invention. FIG. 1B is a partially cutaway front view of the same device.

FIG. 2 is a sectional view of a bush in which the processing position of the seal ring seat groove is changed.

FIG. 3 is a cross-sectional view of a bush in which the processing position of the seal ring seat groove is changed.

FIG. 4 is a sectional view of a conventional bearing-embedded sensor.

[Explanation of symbols]

 1 Electromagnetic pickup 2 Iron core 3 Sensing rotor 4 Sensor mounting hole 5 Non-magnetic bush 6 Set screw 7 O-ring 8 Seat groove 9 Air gap 10 Bearing 11 Inner ring 12 Outer ring

Claims (2)

[Claims] 1. A magnetic field coupling between a sensing rotor fixed to the outer periphery of an inner ring of a bearing and an electromagnetic pickup mounted so as to penetrate the outer ring from the outside so that the inner ring rotates to couple the magnetic field between the sensing rotor and the iron core of the electromagnetic pick. In a bearing-embedded rotation detection device that changes the strength of the electromagnetic pickup to obtain an output signal according to the rotation speed of the inner ring, between the sensor mounting hole of the outer ring and the body of the electromagnetic pickup inserted in the hole. , A bearing built-in type rotation detecting device, characterized in that a non-magnetic rigid bush is fixedly provided on the hole side. 2. The bearing built-in type rotation detecting device according to claim 1, wherein a seal ring is housed in a seat groove provided on an inner surface of the bush and interposed between the bush and the electromagnetic pickup.