| 摘要 |
PURPOSE:To simplify structure, to minimize the influence of backlash, and to improve measurement precision and resolution by converting the rotation of a contact wheel into the rotation of a shaft perpendicular to said wheel and providing numbers of magnetic bodies at the outer periphery of the shaft. CONSTITUTION:A bevel gear 6 fixed coaxially with the contact wheel 1 which profiles a necessary route on a drawing such as a map and another bevel gear 7 engaging said gear are used in combination to convert the rotation of the contact wheel 1 into the rotation of the shaft 8 perpendicular to the contact wheel 1. Many magnetic bodies 9 are provided at axially different positions of the outer periphery of the shaft 8 where the radial phase shifts by, for example, 40 deg., and magnetic sensors 10 corresponding to the magnetic bodies 9 are arranged closely along the shaft 8, thereby counting an AND result among outputs of the respective sensors 10. The resolution is determined by the diameter of the shaft 8 and the phase pitch of the magnetic bodies 9, but the pitch is selected relatively freely by varying the length of the shaft properly, so an encoder is increased in resolution greatly which the size except the length is held constant.
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