JPH03251909A - Rotary encoder positioning method - Google Patents

Abstract

PURPOSE:To facilitate the attachment of a rotary encoder by providing a magnetic disk to a rotary shaft and a hub respectively and securing the coincidence between both reference points via a positioning jig. CONSTITUTION:A hub 21 of a rotary encoder 2 is tentatively fitted at the edge of a rotary shaft 11 so that a magnetic disk 27 is set opposite to a magnetic disk 27 via a gap (g). A positioning jig 3 contains the magnetic sensors 31, 32 on both sides of the jig 3 and includes the reference points P4 and P5 so that both sensors 31 and 32 are coincident with each other and back to back. Then the jig 3 is put into the gap (g) and revolved around the shaft 11, and the sensor 31 detects a reference point P1 of the disk 13. The point P1 is set at the point P4 and the jig 3 is stopped at this coincident position between both points P1 and P4. Then the hub 21 is revolved and a reference point P3 of the disk 27 is detected by the sensor 32. Then the point P3 is set at the point P5 and the hub 21 is stopped at the coincident position between both points P3 and P5. The coincidence is secured among the circumferential directions of the points P1, P2 and P3. Thus, the attachment of the encoder 2 is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary encoder that detects the rotational position of a rotating shaft such as a servo motor, and particularly relates to a method of aligning the origin positions of a servo motor and a rotary encoder.

[Prior Art] Conventionally, when detecting the rotational position of a rotating shaft of a servo motor, a magnetic rotary motor is used, in which scales and origin marks are magnetically written at equal intervals in an annular shape on a rotating disk that rotates with the rotating shaft. Encoders and optical rotary encoders with slits and origin marks on a rotating disk are used. In both cases, in order to detect the rotational position of the servomotor and control the servomotor, the origin is when the magnetic pole positions of the stator and rotor of the servomotor are in a predetermined relationship, and the position of the magnetic pole of the servomotor and the rotary Align the origin of the encoder scale.

In this case, as a first conventional example, a method is disclosed in which a servo motor is rotated to a rotation reference position and an origin mark is written on a rotating disc of a rotary encoder when the rotation reference position is reached (for example, in 64-63809).

In addition, as a second conventional example, in the case of an AC servo motor,
Direct current corresponding to the rated current is applied to the stator windings to excite them and lock the rotor. In this state, the stator and rotor have a constant positional relationship, so the origin position is aligned by aligning the reference position of the rotation axis of the servo motor and the rotary encoder.

[Problems to be Solved by the Invention] By the way, in the first conventional example, a device for writing the origin position is required when setting the origin position, and a servo motor attached to a machine such as a robot is rotated for maintenance etc. Each time the encoder is replaced, an origin writing device is required, which requires a lot of time and effort for maintenance work.

Further, in the second conventional example, a large-capacity DC power supply is required to lock the servo motor, and the rotary encoder can be attached only when the rotation shaft of the servo motor is locked. Therefore, since the rotary encoder cannot be installed while the servo motor is attached to the mating machine, there are drawbacks such as difficulty in replacing the encoder at the customer's site.

An object of the present invention is to easily align the origin with high precision by checking the origin of the motor, which is marked with the motor positioned at a predetermined position, and the origin of the encoder using a magnetic sensor. It is something to do.

[Means for Solving the Problems] The present invention provides a method for positioning a reference point of a rotating shaft of a servo motor and an origin of a rotating disk of a rotary encoder.
A magnetic disk having a reference point on the rotating shaft of the servo motor and a magnetic disk having a reference point matching the origin of the rotating disk on the hub of the rotary encoder are provided, and the magnetic disk provided on the rotating shaft is This is a method for positioning a rotary encoder, in which a reference point and a reference point on a magnetic disk provided in a hub of the rotary encoder are detected by a positioning jig, and the positions of both reference points are made to coincide with each other.

[Operation] A magnetic disk with a reference point is provided on the rotating shaft, a magnetic disk with a reference point that coincides with the origin of the rotating disk is provided on the hub of the rotary encoder, and a positioning jig is used to set the reference points of both magnetic disks. Since the origin is detected and the reference point is made to match, there is no need to lock the servo motor with a large-capacity DC power supply, and if there is a positioning jig,
The rotary encoder can be easily installed while the servo motor is attached to the mating machine.

[Example] The present invention will be described with reference to embodiments shown in the drawings.

FIG. 1 is a side sectional view showing an embodiment of the present invention, in which a hub 21 of a rotary encoder 2 is attached to a rotating shaft 11 of a servo motor l.
This is to ensure that it is fixed. A support part 22 is fixed to the bracket 12 of the servo motor l, and a light emitter 23 and a light receiver 24 of the rotary encoder 2 provided on the support part 22 sandwich a slit 26 of a rotating disk 25 fixed to the hub 21. They are arranged so as to generate a detection signal for the position of the rotating disk 25.

When assembling the rotary encoder 2, as shown in FIGS. 2 and 3, the magnetic disk 13 is fixed to the rotating shaft 11 of the servo motor l, and when the magnetic pole of the servo motor l is at the reference position, In this case, a DC excitation current is applied to the stator winding to magnetize the magnetic disk 13 at the reference point P1 while the rotor is locked.

Further, as shown in FIG. 4, a rotating disk 25 and a magnetic disk 27 are fixed to the hub 21 of the rotary encoder 2 in parallel, and the magnetic disk 27 is attached in the same radial direction as the origin position P2 of the rotating disk 25. A reference point P is magnetized at the position. In addition, in the optical rotary encoder, the origin is provided in the rotating disk 25 by the slit 26, and in the magnetic encoder, the origin is provided by the magnetization pattern.

Next, as shown in FIG.
are slid to face the magnetic disk 13 through the gap g, and are fitted to temporarily fit the magnetic disk 13. Then, magnetic sensors 31 and 32 are provided on both sides in advance, and the reference points P4. A positioning jig 3 provided with P is prepared in advance, and the positioning jig 3 is inserted into the gap g as shown in FIG.

Next, the positioning jig 3 is rotated around the rotating shaft 11 to set a reference point P1 on the magnetic disk 13 of the rotating shaft 11.
is detected by the magnetic sensor 31, the reference point P1 is aligned with P4, and the positioning jig 3 is stopped at that position.

Next, rotate the hub 21 of the rotary encoder 2,
The reference point P of the magnetic disk 27 is detected by the magnetic sensor 32, the reference point P is aligned with P5, and the hub 21 is moved at that position.
The reference points P1 and P2 are stopped as shown in Fig. 5(b).
, P, are aligned in the circumferential direction.

In this state, the hub 21 of the rotary encoder 2 and the rotating shaft 1
1 and fixed.

[Effects of the Invention] As described above, according to the present invention, a magnetic disk with a reference point is provided on the rotating shaft, and a magnetic disk with a reference point that coincides with the origin of the rotating disk is provided on the hub of the rotary encoder. A positioning jig detects the reference points of both magnetic disks and aligns the origin and reference point. This has the effect of making it easier to install the clear encoder and making it possible to replace the encoder at the customer's site.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention, and FIG.
A front sectional view taken along the cross section shown in the figure, FIGS. 3, 4, and 5 (a) and 5 (b) are perspective views illustrating the middle of the process. DESCRIPTION OF SYMBOLS 1... Servo motor, 11... Rotating shaft, 12... Bracket, 13... Magnetic disk, 2... Rotary encoder, 21... Hub, 22... Support part, 25 - Rotating disk, 26 ...Slit, 27...Magnetic disk,
3...Positioning jig, 31, 32...Magnetic sensor 1st
Figure ■ ■ Figure 2

Claims (1)

[Claims] 1. A method for positioning a reference point of a rotating shaft of a servo motor and an origin of a rotating disk of a rotary encoder, comprising: a magnetic disk having a reference point on the rotating shaft of the servo motor; and the rotary encoder. A magnetic disk having a reference point that coincides with the origin of the rotating disk is provided on the hub of the rotary encoder, and the reference point of the magnetic disk provided on the rotating shaft and the reference point of the magnetic disk provided on the hub of the rotary encoder are positioned. A method for positioning a rotary encoder, characterized in that the positions of both of the reference points are matched by detection using a jig. 2. The method for positioning a rotary encoder according to claim 1, wherein the positioning jig has two magnetic sensors on both sides, and the reference points are arranged back to back so that the positions match.