JPS5649916A - Encoder - Google Patents

Abstract

PURPOSE: To enable simple fitting of a slit disc to the exact position in a rotary body in relation to the encoder which transduces a rotary motion into a digital signal.

CONSTITUTION: The encoder is constituted by the rotary body 18, by a ringlike fitting face 20 provided on the side of the rotary body 18 and gearing therewith, by the elastic slit disc 30 having a fitting hole 32 whose bore is shorter than the outer diameter of the face 20 and which is pressed and arranged in the face 20 and by photoreceiving and photoemitting elements 62, 64 and 68 facing each other with the disc 30 between. Moreover, in the inner-peripheral part of the disc 30 are provided a plurality of notches 36 so that the elasticity of the positions facing each othef with the central point of the hole 32 between becomes equal. When the disc 30 is fitted to the rotary body 18 in the above constitution, the hole 32 of the disc 30 is pressed in the face 20. On the occasion, by the presence of the notches 36, the elasticity of the parts positioned symmetrically about the central point of the hole 32 in the inner- peripheral part of the disc 30 becomes equal. Thus, when the hole 32 is pressed in the face 20, the center of the hole 32 accords with the center of the face 20 and thereby the disc 30 is set on the face 20. After that, a press plate 38 is put on the face 20 and the disc is held between the plate 38 and a collar part 18a and fixed by a screw.

COPYRIGHT: (C)1981,JPO&Japio