| 摘要 |
PURPOSE:To enable a braking force to be adjusted in accordance with scatters, if any, of torque generated in a stepping motor on a production basis, by a construction wherein at least one of a pair of brake members is provided with a plurality of spring-fitting parts at intervals so that a friction exerted on an output shaft of a stepping motor can be adjusted by changing the fitting position of a spring. CONSTITUTION:The output shaft 5 of the stepping motor 1 is protruded forward from the center of a circular hole 6 provided at a central part of a fitting plate 2, and is braked by both brake shoes 16. The braking force, namely, the force F exerted on the shaft 5 by the brake shoe is F=(l/L).T, wherein L is the distance between the point of application and a fulcrum of the brake member 11, T is a tensile force of the spring 15 and l is the distance between the tensile force applying point and the fulcrum, and accordingly, the force F is increased with the distance l. The value of the distance l can be changed at three stages l1-l3 according to the positions of three recessed parts 14 of the brake member 11. Namely, the braking force can be adjusted at three stages by selectively fitting the spring 15 to one of the three recessed parts 14. |
