JP2979362B2 - Speed detector - Google Patents

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 for a bearing portion which rotates relatively, and more particularly, to a rotation detecting device for detecting rotation of front and rear wheels in an anti-lock brake system of an automobile incorporated in a seal mechanism. .

[0002]

2. Description of the Related Art Hitherto, the following structure has been frequently used as an anti-skid rotation speed detecting device for preventing skid of an automobile. That is, the rotation speed detection device is a capacitance detection device composed of a toothed rotor and a sensing sensor. At this time, the rotation speed detection device is disposed apart from a sealing device that seals the bearing, and is provided with one independent rotation speed. What constitutes a detection device is common. Less than,
This will be described in detail with reference to the drawings.

In such a conventional example, as shown in FIG. 6, a toothed rotor (7) fitted on a rotating shaft (6) is rotated by a rotation speed detecting sensor (9) mounted on a hub (8). The structure which detects and detects is shown. Here, the bearing (10) is protected from intrusion of moisture or foreign matter by a sealing device (A) provided independently on its side.

[0004]

However, such a structure of the rotational speed detecting device requires a large space dedicated for mounting the toothed rotor (7) and the rotational speed detecting sensor (9), and furthermore, a sealing device. It is inevitable to have a complicated structure such as the parallel arrangement of (A), and is therefore susceptible to vibration or runout, and requires precise polishing of the press-fitted portion in order to secure the detection accuracy. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described drawbacks, and has as its object to provide a rotation speed detection device that detects a wheel rotation with reduced mounting space and dramatically improved sensing performance.

[0005]

The present invention will be described with reference to the drawings. As shown in FIG. 1, a plurality of seal members (1) and (2) which are relatively rotated are integrally incorporated. A rotational speed detecting device, wherein the seal members (1) and (2)
A variable capacitor (4) is formed by providing the electrodes (3) and (3 ') on the circumferential opposing surface of the variable capacitor (4), and the variable capacitor (4) is rotated with the rotation of the electrodes (3) and (3'). As a structure in which the facing area, the facing distance, or the capacitance of the medium between the two electrode plates changes, detecting the number of rotations using the fact that the capacitance of the variable capacitor (4) changes in response to rotation. Features.

Further, as shown in FIG. 5, a rotation number detecting device attached to a plurality of sets of seal members (1) and (2) which rotate relative to each other, wherein the seal member (1)
(2) One side of the sealing member (1 or 2) is provided with a foil electrode (3) on one side and facing the foil electrode (3).
Provided with a toothed pulsar (5), and these members (3)
The number of rotations is detected by utilizing the fact that the capacity of the condenser configured in (5) changes according to the rotation.

[0007]

According to the present invention, the above-mentioned structure has the following excellent effects. The oscillation frequency f of an oscillation circuit including a coil having an inductance L and a capacitor having a capacitance C is roughly expressed by the following equation (1). And the frequency is a function of the capacitance C. Here, since the capacitance C is proportional to the opposing area and opposing distance of the capacitor and the capacitance of the medium between the two electrode plates, the opposing area, opposing distance and the capacitance of the medium between the two electrode plates are increased with rotation. By changing the structure, the capacitance C and the rotation can be associated with each other.

In order to detect the rotation speed on the rotating side by the frequency modulation method under such an operation, for example, if the strip electrode (3) is arranged as shown in FIG. (3) The facing area increases and the frequency decreases. And, after the peak, it increases conversely. Therefore, the rotation speed can be easily calculated from the period change. When the rotational speed on the rotating side is detected by the resonance method, the electrodes (3) are opposed to each other at a narrow pitch as shown in FIG. It is of a type in which the amplitude is modulated in accordance with a change in capacity, and the rotation speed can be calculated by measuring the time between peaks.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to carry out the present invention, FIG. 1 shows an outer ring rotation type, and FIG. 2 shows an inner ring rotation type. In each case, a feeder (11) of a wiring member for detecting rotation is disposed on a fixed side. ing. In FIG. 1, a seal lip (12) is provided on a seal member (2) on the inner ring side, and a seal lip (1) on the outer ring side and a portion where the seal member (2) on the inner ring side are closely opposed to each other. The rotation speed is calculated by providing the foil electrodes (3) and (3 '). 2 is used in a case where the outer ring side is fixed oppositely to FIG. 1, and the attachment of the seal lip (12) is also arranged reversely to FIG. However, the seal lip (12) need not be arranged only on the fixed side as shown in this figure.

Next, as shown in FIG. 3, an electrode (3) is arranged on the stationary side sealing member (1) which rotates mutually.
One of the sealing members (2) facing the foil electrode (3)
It is also possible to arrange a toothed pulsar (5) in which concave and convex portions are alternately cut, and to detect the number of rotations based on a change in capacity corresponding to the rotation of these members (3) and (5). This is a very advantageous structure for mass production at low cost due to simplicity and space saving. In this structure, the embodiment in which the outer ring side is fixed has been described. However, when the inner ring side is fixed, the respective members are naturally arranged in reverse to this structure.

[0011]

According to the present invention, the sealing member (1, 2) is provided.
A variable capacitor (4) is formed by providing an electrode (3), and the rotation speed is detected based on a change in the capacitance of the variable capacitor (4). Further, the present invention does not require a pickup device for picking up the number of teeth, so that high sensitivity can be obtained and space can be saved. In this mounting, since all the members are accurately arranged by the completion of the mounting of the seal members (1, 2), the mounting process itself is reduced. In addition,
It is only necessary to form a variable capacitor (4) on the sealing members (1, 2), and the frequency discrimination circuit, the oscillation / resonance circuit, the amplification circuit, the arithmetic circuit, and the like can be configured separately, so that the arrangement is easy. Maintenance costs can also be reduced.

[0012]

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating the detection method of the present invention.

FIG. 4 is a schematic diagram showing another detection method of the present invention.

FIG. 5 is a sectional view showing another embodiment of the present invention.

FIG. 6 is a sectional view showing a conventional example not using the present invention.

[0013]

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 seal member 2 seal member 3 foil electrode 4 variable condenser 5 toothed pulsar 11 feeder 12 seal lip

Claims (2)

(57) [Claims] A plurality of sealing members (1) that rotate relative to each other.
In the rotation number detecting device attached to (2), the variable capacitors (4) are formed by providing the electrodes (3) and (3 ') on the opposing surfaces of the sealing members (1) and (2), respectively. The variable condenser (4) has a structure in which the facing area and facing distance of the strip electrodes (3) (3 ') or the capacitance of the medium between the two electrode plates change with rotation. Detection device. 2. A plurality of relatively rotating seal members (1).
In the rotation speed detecting device attached to (2), the electrodes (3) and (3) are placed on one of the seal members (1) and (2).
') And a toothed pulsar (5) on one of the sealing members (1 or 2) facing the foil electrode (3).