| 摘要 |
PURPOSE:To improve positioning accuracy by detecting ON-OFF state of annular and arcuate conducting parts. CONSTITUTION:In a permanent magnet-type stepping motor, a rotary shaft 27 passes rotatably through a casing 26 via bearing 28-29 of said casing 26 and a disc 30 is integrally fitted to said shaft to constitute a rotor together with a permanent magnet 31. Also, a coil 32 is wound round the inner peripheral face of the casing 26 in opposition to the permanent magnet 31. Moreover, brushes 33-34 as contacts are erected on the rotor disc 30. In this case, the inner face of the upper part of the casing 26 is fitted with a base 35 and an annular conducting part 36 and an arcuate conducting part 37 are formed on said base 35. While the rotor is rotated, the brush 33 is always in contact with the annular conducting part 36 and the brush 34 touches temporarily the arcuate conducting part 37. With this, if any phase in one phase cycle is excited in a state where both conducting parts 36, 37 are turned ON electrically, the rotor can be located in any one place. |
