JP2010117200A - Optical rotary encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical rotary encoder capable of coping with reduction in size and diameter of a servo motor and having high reliability in which fixing strength of a rotary part is secured. <P>SOLUTION: In the optical rotary encoder including the rotary part 10 to which a glass-made rotary code plate 11 is fixed to a metal-made rotary boss 12 which is attached to a rotary shaft, the rotary boss 12 includes a protruding part 12b for centering on a seat surface 12a on which the rotary code plate 11 is mounted. The rotary code plate 11 includes a plurality of cutout parts 11a (or hole parts) on a concentric circle disposed opposite the seat surface 12a, and fixed by connecting the seat surface 12a with the cutout parts 11a (or hole parts) via an adhesive 13. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure of a rotating part that improves the adhesion strength between a glass rotary code plate and a metal rotary boss of an optical rotary encoder.

  The optical rotary encoder forms a large number of slit patterns for displaying the rotation angle (position) on a rotary code plate, and detects the light transmitted through the slit to measure the rotation angle. This optical rotary encoder is attached to a rotating shaft of a servo motor, for example, and used in a wide range of environments as a drive source for an FA device or the like, and requires high positional accuracy.

  The optical rotary encoder detects the rotation angle of the servo motor rotation and provides position information to the servo amplifier. However, since it is used in a wide range of environments, the rotary part of the optical rotary encoder Is generally composed of a metal rotating boss and a glass rotating sign plate, and is fixed with an adhesive. And it was necessary to withstand high angular acceleration, high-speed rotation, and temperature change.

On the other hand, in order to provide a rotary encoder that can withstand high angular acceleration / high-speed rotation and withstand temperature changes, a central hole is formed in the center of the rotating glass plate, and the rotating shaft has a smaller diameter than the central hole. A flange is formed so that the center convex part protrudes, and the lower surface of the rotating glass plate is brought into contact with the flange through the center hole in this axial center convex part, and the center hole is formed by a bonding auxiliary ring made of a thin metal plate having a diameter slightly larger than the center hole. Adhering the rotating glass plate covers the gap between the shaft and the shaft center convex part, and further overlays a retaining ring on the upper surface of the rotating glass plate and fills the adhesive between the outer peripheral surface of the shaft center convex part and the upper surface of the rotating glass plate A method has been proposed (see, for example, Patent Document 1).
JP-A-9-236450

  The problem to be solved is that along with the miniaturization of servo motors, it is necessary to cope with the reduction in diameter and thickness of optical rotary encoders in addition to high angular acceleration, high-speed rotation, and temperature changes. It is a point that a fixed space cannot be secured and the fixing strength of the rotating part cannot be secured.

  According to the technique of Patent Document 1 described above, it is necessary to add a mechanical fixing such as a retaining ring in addition to the adhesive, which not only complicates the assembly process but also increases the length in the axial direction. .

  In addition, since the bonding area between the rotary code plate and the rotary boss is reduced by reducing the diameter, there is a problem that the adhesive strength is insufficient and the rotary code plate is easily peeled off.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problems, and to provide a highly reliable optical rotary encoder that can cope with a reduction in the size and diameter of a servo motor and that secures the fixing strength of a rotating part.

In order to solve the above-described problem, the optical rotary encoder according to claim 1 has a rotating portion in which a glass rotation code plate is fixed to a metal rotating boss, and the rotating boss is attached to a rotating shaft. In the rotary encoder, the rotating boss has a centering convex portion on a seating surface on which the rotating code plate is mounted, and the rotary code plate has a plurality of notches or holes on a concentric circle facing the seating surface. And the seating surface and the notch or hole are connected and fixed by an adhesive.

  According to a second aspect of the present invention, in addition to the first aspect, the optical rotary encoder is provided with a recess on a concentric circle of the seating surface facing the notch or the hole.

  Furthermore, in addition to claim 2, the optical rotary encoder according to claim 3 secures an adhesive strength in the axial direction at the seat surface, and rotates in the rotational direction at the notch or the hole and the recess. Use different types of adhesives to ensure adhesive strength.

  According to the optical rotary encoder of the first aspect, since the bearing surface of the rotating boss and the cutout portion or the hole portion of the rotating code plate are connected and fixed with the adhesive, the insufficient adhesive strength due to the insufficient adhesive area is improved. Can do.

  According to the optical rotary encoder of the second aspect, since the concave portion is provided on the seating surface of the rotating boss and is adhered to the cutout portion or the hole portion of the rotary code plate, the adhesive that has entered the concave portion is rotated in the rotation direction. On the other hand, since it plays the role of a wedge, the adhesive strength in the rotational direction is further increased.

  Furthermore, according to the optical rotary encoder of claim 3, different types of adhesives that secure the adhesive strength in the axial direction at the seating surface and secure the adhesive strength in the rotational direction at the notch portion or the hole portion and the concave portion are provided. By using it, it is possible to obtain a highly reliable optical rotary encoder that can cope with a reduction in diameter and secures the fixing strength of the rotating portion.

  In an optical rotary encoder having a rotating part in which a glass rotary code plate is fixed to a metal rotary boss and attaching the rotary boss to a rotary shaft, the rotary boss is mounted on a seat surface on which the rotary code plate is mounted. The rotating code plate has a plurality of notches or holes on a concentric circle facing the seat surface, and the seat surface and the notches or holes are formed with an adhesive. It is connected and fixed, and is provided with a recess on a concentric circle of the seating surface facing the notch or hole. Hereinafter, embodiments will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view of a rotary code plate according to Embodiment 1 of the present invention. In FIG. 1, a glass rotary code plate 11 is provided with two arc-shaped notches 11a outside a central hole portion 11b. In the vicinity of the outer periphery, bright and dark slits (not shown) are provided.

  FIG. 2 is a cross-sectional view of the rotating part of the present invention. The rotating unit 10 includes the rotary code plate 11 and the rotating boss 12 illustrated in FIG. 1 and is fixed with an adhesive 13. The rotating boss 12 is made of stainless steel and includes a seating surface 12a on which the rotating code plate 11 is mounted, a convex portion 12b for centering the rotating code plate 11, and a shaft hole 12c into which the rotating shaft is inserted. Can be obtained by:

  A feature of the present invention is that a plurality of cutout portions 11 a are provided on a concentric circle facing the seating surface 12 a of the rotating boss 12 on the glass rotary code plate 11, and the seating surface 12 a and the cutout portion 11 a are connected and fixed by an adhesive 13. In the point. Thereby, the adhesive strength in both the axial direction and the rotational direction can be increased.

FIG. 3 is a sectional view of an essential part of the optical rotary encoder. In FIG. 3, the light receiving element 14 is attached to a predetermined position of the light receiving circuit board 15 together with peripheral circuit components by soldering. The fixed code plate 16 is bonded and fixed in alignment with the light receiving element 14.

  The rotating unit 10 described in FIG. 2 is fixed to a rotating shaft 17 of the motor. The light emitting element 18 is attached to the light emitting circuit board 19 together with peripheral circuit components by soldering. When the light emitting circuit board 19 and the light receiving circuit board 15 are attached to the encoder frame 20, the optical axis is adjusted so that the optical axis of the light emitting element 18 is orthogonal to the light receiving part of the light receiving element 14, and the rotating part and the fixed part are separated. Optical rotary encoder.

  In the first embodiment, the rotary code plate 11 is provided with the cutout portion 11a. However, even if a plurality of holes (not shown) are provided on the concentric circle facing the seating surface 12a of the rotary boss 12, the same applies. can do.

In particular, when the optical rotary encoder has a small diameter, if the cutout portion is provided in the rotary code plate, both the sign portion and the rotary boss are not affected, and a sufficient effect can be obtained with the same size as the conventional one.
(Embodiment 2)
FIG. 4 is a cross-sectional view of the rotating portion of the second embodiment. The difference from the first embodiment is only that a concave portion is provided on the seating surface of the rotating boss, and the difference will be mainly described.

  In FIG. 4, a recess 22 c is provided in the seat surface 22 a of the metal rotating boss 22. The recess 22c can be obtained by cutting as in the first embodiment by providing the recess 22c over the entire circumference at a position facing the notch 11a of the rotary code plate 11. Moreover, even if it changes the notch part 11a of the rotation code | symbol plate 11 into a hole part, it can implement similarly.

  The adhesive 13 is applied to the seating surface 22a of the rotating boss 22 and the rotating code plate 11 is placed thereon, and once cured. Further, a different adhesive 23 is applied from the notch 11a to the recess 22c and cured. The adhesive 23 applied to the notch 11a enters the recess 22c, exhibits a wedge effect, and increases the adhesive strength.

  For example, an anaerobic adhesive is used for the adhesive 13 in order to ensure the adhesive strength in the axial direction, and an epoxy adhesive is used for the adhesive 23 in order to ensure the adhesive strength in the rotational direction.

  With the above-described configuration, the diameter can be reduced, and an optical rotary encoder that can withstand high angular acceleration and high-speed rotation can be obtained by increasing the adhesive strength.

  The optical rotary encoder of the present invention is particularly effective for reducing the diameter, but it goes without saying that a normal optical rotary encoder can also be implemented. Further, the rotating boss is not limited to stainless steel, and a metal that is close to the expansion coefficient of glass and has good workability is desirable.

  The optical rotary encoder of the present invention is useful for miniaturization of a servo motor.

The top view of the rotation code | symbol plate in Embodiment 1 of this invention Sectional drawing of the principal part of the rotation part in Embodiment 1 of this invention Sectional drawing of the principal part of the optical rotary encoder in Embodiment 1 of this invention Sectional drawing of the principal part of the rotation part in Embodiment 2 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rotation part 11 Rotation code | symbol 11a Notch part 11b Center hole part 12, 22 Rotation boss 12a, 22a Seat surface 12b, 22b Protrusion part 13, 23 Adhesive 14 Light receiving element 15 Light receiving circuit board 16 Fixed code board 17 Rotating shaft 18 Light emission Element 19 Light emitting circuit board 20 Encoder frame 22c Recess

Claims (3)

In an optical rotary encoder that has a rotating part in which a glass rotation code plate is fixed to a metal rotating boss, and attaches the rotating boss to a rotating shaft,
The rotating boss has a centering projection on a seating surface on which the rotation code plate is mounted,
The rotary code plate has a plurality of notches or holes on a concentric circle facing the seat surface,
An optical rotary encoder, wherein the seating surface and the notch or hole are connected and fixed with an adhesive.   The optical rotary encoder according to claim 1, wherein a concave portion is provided on a concentric circle of the seating surface facing the notch or the hole.   3. The optical rotary encoder according to claim 2, wherein different types of adhesives are used to secure an adhesive strength in the axial direction at the seating surface and secure an adhesive strength in the rotational direction at the notch or the hole and the recess.

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