| 摘要 |
PURPOSE:To eliminate the need for thrust adjustment and washers in an eddy current type tachometer by providing a circumferential groove to a revolving shaft, fitting said groove into the fitting hole of a metallic plate fixed to a body and suspending the shaft freely rotatably. CONSTITUTION:A revolving shaft 4 fixed with a magnet 5 is a synthetic resin and is molded in one body with a stem part 4a to be inserted slidably into the boss part 1b of a body 1, gear teeth 4b, and a magnet holding part 4e. Further, a circumferential groove 4f is formed in the side end part of the gear teeth 4b of the part 4a. Said groove fits into the fitting hole 3d of a yoke 3. To this end, the fitting hole consists of a small diameter part provided at the center and a large diameter part provided in continuation with said small diameter part. In assembling, the step part 4a is passed into the large diameter part and the groove 4f is matched with the position of the fitting hole; thereafter, the groove 4f is fitted into the small diameter part. |
