| 摘要 |
PURPOSE:To eliminate the backlash between a worm and a worm gear, by dividing the worm gear in a speed reducing mechanism comprising the worm and the worm gear, and linking the divided parts with a spring. CONSTITUTION:The speed reducing mechanism 5 comprising the worm 3 and the worm gear 4 is provided on a rotary shaft 2 of the pulse motor 1. The speed reducing mechanism 5 and a pointer shaft 7 of a pointer 6 are linked by a spiral spring 8. The pointer shaft 7 is supported upright in a tubular body 10, which is provided in the measuring instrument body 9 and filled up with oil, by a ball 11 at the lower end of the pointer shaft 7 and a damper 12 at the outer surface of the pointer shaft 7. The worm gear 4 is divided at the central engaging part with the worm 3. The divided part are linked by the torsion spring 13, which is enclosed in the recessed part formed in the bearing surface of the gear, with a phase being shifted. |
