JPH07218248A - Bearing with rotation angle detector - Google Patents

Abstract

PURPOSE:To stably and exactly detect rotational angle of a rotor by letting an inductor probe provided in a ring on one side of the bearing touch a coded pattern made of an inductor body and insulator body formed on a rotary wheel side. CONSTITUTION:An insulation layer 3 is formed on the end surface of an outer wheel 1 of bearing, and on it, an induction body pattern 4 is formed in concentric of the bearing shaft axis. This pattern 4 is coded so as to express the absolute angle with the combination of plural numbers by covering the inductor with insulator at a specific angle. The inductor circle in the center operates as a common electrode. On the other hand, a probe 5 formed with inductor is fixed on an inner wheel 2 and the pattern 4 corresponding to the angle is short-circuited to the common electrode. The rotational angle (absolute angle) is detected through digital values depending on the path between the pattern 4 and the common electrode. With this constitution, it is not affected by electric noise and detection accuracy does not lower till the pattern 4 chips off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing with a rotation angle detector, and more particularly to a bearing with a rotation angle detector for detecting the relative rotation angle of first and second rotating bodies that rotate coaxially.

[0002]

2. Description of the Related Art FIG. 3 is a view showing a usage state of a conventional rotation angle detecting device, and is a front view showing a main part of a joint part 33 of an articulated robot, and FIG. 4 is a partially broken view of FIG. It is the side view shown. In the joint part 33 of the multi-joint robot, a rotary shaft 31 a provided at the end of one arm 31
Is rotatably provided via a bearing 34 in a support hole 32a provided at the end of the other arm 32.
Further, the joint portion 33 is provided with a rotation angle detection device 36 for detecting an angle between the arms 31 and 32, and a rotation shaft 36 a of the rotation angle detection device 36 has a coupling 35.
Is connected to the rotary shaft 31a via a rotary angle detecting device 3
The 6 main body is fixed to the arm 32 via a support member 37. A variable resistor (not shown) whose electric resistance value changes according to the rotation angle θ of the rotation shaft 36a is provided in the rotation angle detection device 36, and based on the electric resistance value of this variable resistor, The angle θ between the arms 31 and 32 is detected,
Furthermore, the operations of the arms 31 and 32 are controlled.

[0003]

However, in the above-mentioned articulated robot, many problems of the rotation angle detection device 36 and a short life thereof have been problems. The cause is that the resistor of the variable resistor used in the rotation angle detection device 36 is quickly worn by the violent operation of the articulated robot. Further, since the output signal is an analog amount, it is likely to be affected by electrical noise from the outside, which may cause a malfunction of the device.

Therefore, a main object of the present invention is to provide a bearing with a rotation angle detector which can stably and accurately detect the rotation angle of a rotation pair.

[0005]

A bearing with a rotation angle detector according to claim 1 is a separate body or a contactor made of a conductor provided on one ring of the bearing, and a conductor and an insulator on the rotating ring side of the bearing. And a plurality of coded concentric circle patterns or patterns on the same peripheral surface.

In the invention according to claim 2, the concentric pattern or the pattern on the same circumference according to claim 1 is formed by directly patterning an insulating pattern on the rotating wheel side.

In the invention according to claim 3, the contact position of the contact according to claim 1 and the concentric circle pattern are shifted so that there is a phase difference so that one kind of concentric circle pattern is provided, and thus the incremental angle detection is performed. Make up a container.

[0008]

In the bearing with rotation angle detector according to the present invention, the concentric pattern or the pattern on the same circumference in which the conductor and the insulator are arranged and the contact formed from the conductor move on the pattern. , The rotation angle is detected by a digital amount indicating the presence or absence of conduction.

[0009]

FIG. 1 is a diagram showing an embodiment of the present invention.
As shown in FIG. 1 (a), the bearing with a rotation angle detector includes an outer ring 1 and an inner ring 2, an insulator layer 3 is formed on an end surface of the inner ring 2, and as shown in FIG. A pattern 4 made of a conductor is formed on the top of the bearing so as to be concentric with the bearing axis. This pattern is coded so that the absolute angle can be expressed by combining a plurality of wires by covering the conductor with an insulator at an angle determined as necessary. Further, the conductor circle in the center portion acts as a common electrode and is formed on the circumference which is not cut.

On the other hand, a contactor 5 made of a conductor is attached to the inner ring 2 as shown in FIG. 1B, and the common electrode and the conductor pattern corresponding to the angle are short-circuited depending on the rotation angle. By this, by the digital value encoded by the presence or absence of conduction between each conductor pattern and the common electrode,
The absolute angle can be detected.

The same effect can be obtained even if the outer ring 1 main body is used as a common electrode and a similar pattern is formed by an insulator such as an oxide film whose end face is oxidized, and the contacts 5 are independent of each pattern. Can be miniaturized.

In the above description, the pattern 4 is formed on the end surface of the outer ring 1, and the contact 5 is attached to the outer ring 2 facing the surface.
However, the outer ring 1 may be provided with the contact 5 and the inner ring 2 may be formed with the conductor pattern 4.

Further, in the above description, the absolute type is shown, but in the case of the incremental type, the pattern pitch may be realized by two concentric circles whose phases are shifted by 90 degrees. Also, this phase difference is due to the contact 5
The contact position may be shifted on the side. At this time,
The pattern is only one kind of radial lattice pattern.

FIG. 2 is a diagram showing another embodiment of the present invention. In this embodiment, a plurality of patterns 6 as shown in FIG. 2B are formed along the axial direction on the outer peripheral surface of the inner ring 2 shown in FIG. 2A. A contact 5 is provided on the inner peripheral surface of the outer ring 1 facing the outer peripheral surface of the inner ring 2 so as to contact the pattern 6. In the embodiment shown in FIG. 2 as well, when the contact 5 comes into contact with the pattern 6, it is possible to output a coded digital signal.

In the core embodiment shown in FIGS. 1 and 2, the contact 5 is provided on the outer ring 1, but the contact 5 may be provided separately from the outer ring 1 and independently.

[0016]

As described above, according to the present invention, the concentric circle pattern or the pattern on the same circumferential surface in which the conductor and the insulator are alternately arranged, and the contact formed by the conductor moves on the pattern. By doing so, the rotation angle can be detected by a digital amount indicating the presence or absence of conduction. Moreover, since the bearing with a rotation angle detector outputs a digital value, it is not easily affected by electrical noise, and the accuracy of the resistor is deteriorated by abrasion as in the conventional case. Since the detection is performed and the digital signal is output, the accuracy does not decrease until the pattern is lacking.Therefore, using a resistor makes it possible to maintain the accuracy stably over a long period of time, and to reduce the service life. Can be lengthened.

[Brief description of drawings]

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

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

FIG. 3 is a diagram showing a usage state of a conventional rotation angle detector.

FIG. 4 is a side view showing a part of FIG. 3 in a cutaway manner.

[Explanation of symbols]

 1 Outer ring 2 Inner ring 3 Insulator layer 4, 6 Pattern 5 Contact

Claims (3)

[Claims] 1. A contact made of a conductor provided separately from the bearing or on one ring of the bearing, and a plurality of coded concentric circle patterns or the same made up of a conductor and an insulator on the rotating wheel side of the bearing. Bearing with rotation angle detector, which has a pattern on the circumferential surface. 2. The bearing with a rotation angle detector according to claim 1, wherein the concentric circle pattern or the pattern on the same circumference is formed by directly patterning an insulating pattern on the rotating wheel side. 3. An incremental angle detector is constructed by shifting the contact position between the contactor and the concentric circle pattern so as to give a phase difference so that the concentric circle pattern becomes one type. 1. Bearing with rotation angle detector.