JPH047815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a direct-coupled encoder suitable for detecting the amount of rotation of a rotating device such as a servo motor.

[Conventional technology]

In recent years, in the field of automatic control, there has been significant progress in the miniaturization and higher precision of equipment. In particular, in rotating equipment such as servo motors, the motor itself is not only smaller, but also an encoder (rotary encoder) that detects the amount of rotation is directly connected to and built into the motor, thereby integrating the motor and detector. The aim is to reduce the overall size and improve precision.

FIG. 2 is a sectional view showing the configuration of such a direct-coupled encoder. In this diagram, motor 1
A journal 3 is formed in the casing 2, and a ball bearing 5 is fitted into the journal 3 via a wave washer 4 for buffering. The ball bearing 5 supports a rotating shaft 6 of the motor 11, and a rotary slit plate 8 of an encoder 7 is fixed to one end of the rotating shaft 6 so as to rotate together with the rotating shaft 6. A large number of fine slits extending in the radial direction are carved concentrically on the outer peripheral edge of the rotating slit plate 8, and when the rotating slit plate 8 rotates, these slits (slits on the rotating side) are activated by the photoelectric switch of the detection unit 9. (not shown). As a result, the photoelectric switch outputs a number of pulses proportional to the amount of rotation of the rotating slit plate 8, that is, the amount of rotation of the rotating shaft 6.

The detection section 9 is provided with a fixed slit 10 for converging the light from the photoelectric switch, and the components 8 and 9 constitute the encoder 7.

The encoder 7 described above is widely used in the field of automatic control of servo motors and the like because it can detect even minute amounts of rotation with extremely high accuracy.

[Problem that the invention seeks to solve]

Incidentally, in the encoder 7, the thrust load applied to the rotating shaft 6 causes the rotating shaft 6 to move in the thrust direction by the clearance of the ball hair ring 5 and the deflection of the wave washer 4, so that it is not fixed to the rotating shaft 6. The rotating slit plate 8 also moves by that amount, and the rotating slit plate 8 and the fixed side slit 1
There was a phenomenon in which the gap G with respect to 0 changed. When the gap G widens, the detection light beam from the detection section 9 leaks, causing a problem in that accurate rotation amount detection cannot be performed.

This invention attempts to solve the above problems.

[Means for solving problems]

In order to solve the above problems, the present invention provides a thrust bearing fitted onto a rotating shaft of a rotating device,
a detection unit base fixed to the thrust bearing and slidably attached to the casing of the rotating device in the thrust direction; and an urging means for urging the detection unit base in a direction to press the thrust bearing; The detection unit of the encoder is attached to the detection unit base.

[Effect]

According to the above configuration, since the detection unit base and the rotating shaft always move together, the gap G between the detection unit fixed to these and the rotating slit plate is always constant, which prevents the detection light beam from leaking. can do.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing the configuration of an embodiment of the present invention, and parts corresponding to those in FIG. 2 are given the same reference numerals and explanations will be omitted.

In this figure, one end of the rotating shaft 6 protrudes to the outside of the casing 2, and a thrust bearing 11 is fitted into this protruding portion. On the other hand, a thrust bearing 1 is attached to the outer peripheral edge of the casing 2.
A cylindrical wall portion 12 is formed to surround 1, and a detection base 13 fixed to a thrust bearing 11 is fitted into the inner periphery of this wall portion 12 so as to be slidable in the thrust direction. Further, the detection unit base 13 is
The thrust bearing 11 is biased in the direction of pressing by a biasing means 16 consisting of a screw 14 and a spring 15 fitted onto the screw 14 . That is, a spring 15 is fitted around a screw 14 that is loosely fitted into a through hole 17 formed at one corner of the detection base 13 and fixed to the casing 2, and the detection base 13 is moved downward in the figure, that is, in a thrust direction. The bearing 11 is biased in the direction of pressing. Further, this detection unit base 13 includes a detection unit 9.
is fixed, and components 8 to 17 constitute a direct-coupled ender 18.

In such a configuration, when the rotating shaft 6 moves upward in the figure, the detection unit base 13 fixed to the thrust bearing 11 also moves together with the rotating shaft 6. Furthermore, even when the rotating shaft 6 moves downward in the figure, the force of the biasing means 16 causes the detection unit base 1 to
3 moves together with the rotating shaft 6. In this way, since the detection unit base 13 always moves together with the rotating shaft 6, the gap G between the fixed side slit 10 of the detection unit 9 fixed thereto and the rotating slit plate 8 is always kept constant. It is possible to prevent the detection light from spreading.

〔Effect of the invention〕

As explained above, in this invention, the detection part is attached to the rotating shaft via the detection part base and the thrust bearing, and the gap between the fixed side slit of the detection part and the rotating slit plate is always kept constant. , the amount of rotation can always be detected with high precision without spreading the detection light of the detection unit.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention, and FIG. 2 is a sectional view showing the structure of a conventional direct-coupled encoder. 1...Motor (rotating equipment), 2...Casing, 6
...Rotating shaft, 7, 18... Encoder, 8... Rotating slit plate, 9... Detecting section, 11... Thrust bearing, 13... Detecting section base, 16... Biasing means.

Claims (1)

[Claims] 1. In a direct-coupled encoder that includes a rotating slit plate directly attached to the rotating shaft of a rotating device and a detection unit that detects the slit formed on the rotating slit plate, a thrust plate fitted onto the rotating shaft of the rotating device a bearing; a detection unit base fixed to the thrust bearing and slidably attached to the casing of the rotating device in the thrust direction;
A direct-coupled encoder, comprising: urging means for urging the detection unit base in a direction to press the thrust bearing, and the detection unit is attached to the detection unit base.