JPH0587822A - Rotational speed detecting device for rolling bearing - Google Patents

Abstract

PURPOSE:To provide a rotation detecting device capable of detecting rotation accurately from low speed zone and high in durability against high temperature. CONSTITUTION:A pulsar ring 4 is installed on a rotating outer ring 3 of a rolling bearing 1, and a detecting ring 7 is installed on an stationary inner ring 2. Then multiple teeth 9, 10, and 10' of equal pitch are provided around the periphery of these both rings 4 and 7, respectively. The detecting ring 7 is divided in circumferential direction, the teeth 10 and 10' at the divided portion are deviated by half pitch, and coils L10 and L20 are wound on the divided portions, respectively. The coil L is excited by high-frequency voltage and, when the rings 4 and 7 are rotated relatively, an inductance of the coils L10 and L20 is varied due to variation in magnetic resistance. By extracting the variation, the rotational speed of a rolling bearing can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed detecting device for a rolling bearing, which is used, for example, for detecting the rotation speed of a wheel in a vehicle and the rotation angle of a steering shaft.

[0002]

2. Description of the Related Art In an anti-skid braking system installed in an automobile, it is required to accurately detect the rotational speed of wheels from a low speed to a high speed range.

Conventionally, such wheel rotation speed detection is
A pulsar ring, which has a large number of gear-shaped teeth on its peripheral surface, is attached to a rotating member, and an electromagnetic pickup is faced to the peripheral surface of the pulsar ring, and changes in magnetic flux caused by rotation of the pulsar ring are detected as voltage changes. Is done in a way.

However, this method has a drawback in that the output voltage is lowered when the wheel rotation speed becomes low, so that the detection accuracy of the rotation speed is remarkably deteriorated, and in particular, the detection cannot be performed near the 0 speed.

On the other hand, a pulsar ring having N and S poles alternately magnetized on the peripheral surface is attached to a rotating member, and a magnetic conversion element such as a Hall element is opposed to the pulsar ring to detect the rotation speed. A method is being considered.

However, in the case of the above structure, since the magnetic conversion element is usually composed of a transistor having a PN junction, the allowable temperature is set low due to the heat resistance of the PN junction itself, and at the time of energization. Are limited to even lower available temperatures. For this reason, there is a problem that durability deteriorates in an atmosphere near the wheels, which is heated to a high temperature by a brake operation or the like.

Therefore, according to the present invention, by mounting it on a rolling bearing that supports a rotating shaft, it is possible to accurately detect the rotating speed in a wide range from a low speed to a high speed range, and further, it is durable even in a high temperature atmosphere. It is an object of the present invention to provide a rotation detecting device that does not deteriorate and can perform stable operation.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention mounts rings made of magnetic material on both bearing rings of a rolling bearing with their peripheral surfaces facing each other, and A large number of teeth are provided on the peripheral surface at the same pitch, the fixed side ring is divided into two parts in the radial direction, and the teeth of each divided part are arranged by being shifted by a half pitch in the circumferential direction, and A coil is wound around each of the divided portions, the respective coils are connected to each other, and a high frequency voltage adding means and a signal processing means for detecting a voltage change at the coil connecting portion are connected to the connected coil. ..

The signal processing means includes a circuit for rectifying and smoothing an input signal and a comparing circuit for comparing the smoothed signal with a reference value, and may be integrated in the connector. it can.

The coil may be incorporated inside an oil seal provided on one of the bearing rings.

[0011]

In the above structure, when the coil is excited by a high frequency voltage, a magnetic circuit is formed between each ring of magnetic material and the coil. When each ring relatively rotates from this state, the magnetic resistance (reactance) between the divided portion and the rotating side ring changes due to the facing state of the tooth of each divided portion of the fixed side ring and the tooth of the rotating side ring. This change in resistance
The rotational speed of the bearing can be known by extracting the voltage change at the coil connection and comparing it with a reference value.

In the above structure, since the rotational speed is detected from the change in the reactance of the coil, the circuit speed can be accurately detected even at 0 speed or the low speed range in the vicinity thereof. Further, since a magnetic ring or coil can be attached to the bearing and the high frequency power supply adding means and the signal processing means can be arranged separately from them, stable speed detection can be performed even in the vicinity of the wheel which is in a high temperature state.

On the other hand, when a ring or a coil is installed inside the rolling bearing, it is desirable to seal the coil to protect it from lubricant and metal powder contained therein. In that case, the coil is integrated inside the oil seal. When it is assembled into the bearing, the dedicated seal member can be omitted, and the device can be compactly assembled into the bearing.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The rolling bearing 1 in FIG. 1 (a) is used by fixing the inner ring 2 and rotating the outer ring 3, and a pulsar ring 4 made of a ferromagnetic material is attached to the inner diameter surface of the outer ring 3 on the rotating side. ..

Further, a seal member 6 which is in sliding contact with the oil seal 5 attached to the outer ring 3 is attached to the outer diameter surface of the inner ring 2 on the fixed side, and the detection ring 7 is incorporated in the seal member 6 and the detection ring. The tip of 7 is the pulsar ring 4
Are mounted so that their peripheral surfaces face each other. The detection ring 7 is made of a ferromagnetic material, and the inner peripheral portion thereof is press-fitted and fixed to the outer diameter of the non-magnetic core metal 8 of the seal member 6.

The inner peripheral surface of the pulsar ring 4 is shown in FIG.
As shown in FIG. 5, a large number of gear-shaped teeth 9 are formed at an equal pitch over the entire peripheral surface.

On the other hand, the outer circumference of the detection ring 7 is divided into four yokes 7a, 7b, 7c, 7d in the circumferential direction, and the pitches equal to the teeth 9 of the pulsar ring 4 are provided on the outer circumferential surfaces of the respective yokes 7a-7d. In this way, a large number of teeth 10, 10 'are formed. In this case, among the four yokes 7a to 7d, the teeth 10 of one pair of adjacent yokes 7a and 7b and the teeth 10 'of the yokes 7c and 7d of the other set face the recesses of the teeth 9 of the pulser ring 4. In order to face the convex portion of each tooth 9 of the pulsar ring 4, the phase is shifted by a half pitch of the tooth in the circumferential direction. Since the high-frequency magnetic field acts on the pulser ring 4 and the detection ring 7 described above, good magnetic characteristics can be obtained by stacking silicon steel plates.

Further, the yokes 7a, 7b, 7c, 7
At the neck of d, coils L ₁ , L ₁ ', L ₂ , L
₂ 'is wound in a state of being incorporated in the sealing member 6. Of the coils, the yoke 7a,
Two sets of coils L ₁ and L ₁ ′ and coils L ₂ and L ₂ ′ corresponding to the set of 7b and the yokes 7c and 7d are connected in series with each other (hereinafter, the connected coils L ₁ and L ₁ ′ will be referred to as a whole). Coil L ₁₀ , coil L ₂ , L ₂ 'whole coil L ₂₀
Further, the coil L ₁₀ and the coil L ₂₀ are connected in series, and the high frequency voltage adding means 11 is connected to the ends of the coils L ₁₀ and L ₂₀ . This high frequency voltage adding means 11 is composed of a sine wave of several tens KHz
It intended to transmit a high-frequency voltage to the coil L _10, L _20, exciting by adding a high-frequency voltage to the coil L _10, L _20.

Further, a signal processing means 13 for inputting a voltage change of the connection portion 12 is connected to the connection portion 12 of each of the coils L ₁₀ and L ₂₀ . This means 13 comprises a rectifying circuit 14 for rectifying and smoothing the voltage signal, a smoothing circuit 15, and a comparison circuit 16 for comparing the smoothed signal with a reference value m.

The signal processing means 13, together with the high frequency power supply adding means 11, is integrally built in the power supply and output signal connector provided at a position distant from the rolling bearing 1, and is dependent on the high temperature inside and around the bearing. Elements such as internal ICs are arranged so as not to be affected.

Further, the signal processing means 13 and the coils L ₁₀ and L
_A three-core shielded cable 17 is connected to the cable ₂₀ to prevent external noise from entering.

This embodiment has the above-mentioned structure, and its operation will be described below.

When a high frequency voltage V ₁ is applied to the coils L ₁₀ and L ₂₀ of the detection ring 7 to excite them, the respective coils L ₁₀ and L ₂₀ are excited.
A magnetic circuit is formed by L ₂₀ , the detection ring 7, and the pulser ring 4.

From this state, when the rolling bearing 1 rotates and the pulsar ring 4 and the detection ring 7 relatively rotate, the magnetic resistance of the magnetic circuit changes.

In this case, as shown in FIG. 2, coil L ₁₀
When the teeth 10 of the wound yokes 7a and 7b match the unevenness of the teeth 9 of the pulsar ring 4, the teeth 10 'of the wound yokes 7c and 7d of the coil L ₂₀ are opposite to the unevenness of the teeth 9 of the pulsar ring 4. It becomes the state of. In this state, the resistance of the magnetic circuit formed by the coil L ₁₀ is smaller than the resistance of the magnetic circuit formed by the coil L _20, so that the inductance of the coil is larger in the coil L ₁₀ than in the coil L _20. Become.

On the other hand, in the opposite case of the state shown in FIG. 2, on the contrary, the inductance of the coil L ₂₀ increases and the inductance of the coil L ₁₀ decreases.

That is, the connecting portion 12 of the coils L ₁₀ and L ₂₀
The output voltage V ₂ of ₁ changes with the relative rotation of the pulser ring 4 and the detection ring 7 even if the applied voltage V ₁ of the high frequency voltage adding means 11 is constant. For this reason,
The output voltage V ₂ of the coil connecting portion 12 is supplied to the signal processing means 1
By rectifying and smoothing in 3, the carrier component f ₀ is removed, and then the processed voltage is compared with the reference value m in the comparison circuit 16 to obtain a rectangular wave signal accompanying the rotation of the pulser ring 4. You can

Here, the voltage of the reference value m in the comparison circuit 16 takes the median value of the change of the output voltage V ₂ caused by the combination of the teeth 9, 10, 10 ′ of both rings 4, 7. in practice, if a voltage value of 1/2 of a value obtained by rectifying and smoothing the V ₁ of the applied voltage, even when the applied voltage V ₁ is varied, it is possible to always set the reference value at a constant rate, Stable signal processing can be performed.

On the other hand, FIG. 3 shows another embodiment. In this example, the oil seal 2 made of rubber is provided on the outer diameter surface of the inner ring 2.
1 is attached, and the detection ring 22 and the coil L are integrally incorporated in the oil seal 21 by molding. Reference numeral 23 is a three-core cable that connects the coil L and the signal processing means. In the above structure, FIG.
A seal member 6 for sealing the coil L as shown in FIG.
Does not need to be provided separately from the oil seal 5, the structure inside the bearing is simplified, and the device can be made compact. The other structure and the signal processing structure are the same as those of the embodiment shown in FIGS.

In each of the above-described embodiments, an example in which the outer ring of the rolling bearing is rotated has been shown, but the present invention can be similarly implemented when the inner ring is rotated. In this case, the pulsar ring is attached to the rotating inner ring and the detection ring is attached to the outer ring.

[0031]

As described above, according to the present invention, one of the rings provided facing each other is divided, the teeth on the outer periphery of the divided portion are shifted by a half pitch, and the rotational speed is determined by the difference in reactance of the coil wound around the divided portion. Is detected, it is possible to accurately detect the rotation speed in a wide range from the 0th speed and its low speed range to the high speed range.

Further, since the signal processing means including a transistor and the like can be arranged separately from the magnetic material ring or coil incorporated in the bearing, the durability is stable and stable even in a high temperature atmosphere. Speed detection can be performed.

[Brief description of drawings]

FIG. 1A is a sectional view showing an internal structure of a rolling bearing of an embodiment, and b is a block diagram showing a signal processing structure of the same.

FIG. 2 is a front view showing the pulsar ring and the detection ring of the above.

FIG. 3 is a cross-sectional view showing another embodiment.

[Explanation of symbols]

1 rolling bearing 2 inner ring 3 outer ring 4 pulsar ring 6 sealing member 7 detecting ring 9 teeth 10, 10 'tooth 11 high-frequency voltage adding means 12 connecting section 13 signal processing unit 21 the oil seal 22 detector ring L _10, L ₂₀ coils

Claims (3)

[Claims] 1. Rings made of a magnetic material are attached to both races of a rolling bearing with their circumferential surfaces facing each other, and a large number of teeth are provided on the circumferential surfaces of both rings at the same pitch to fix the fixed side. The ring is divided into two parts in the radial direction, the teeth of each of the divided parts are arranged so as to be displaced by a half pitch in the circumferential direction, and the coils are wound around each of the divided parts to connect the coils to each other. Then, a rotational speed detecting device for a rolling bearing, wherein the connected coil is connected with a high-frequency voltage adding means and a signal processing means for detecting a voltage change at a connecting portion of the coil. 2. The signal processing means comprises a circuit for rectifying and smoothing an input signal and a comparison circuit for comparing the smoothed signal with a reference value, which is integrated in a connector. A rotation speed detecting device for the rolling bearing described. 3. The rotation speed detecting device for a rolling bearing according to claim 1, wherein the coil is incorporated inside an oil seal provided on one of the bearing rings.