| 摘要 |
Belt pulleys with a variable effective diameter comprise identical nested driving pulleys which are mounted on identical hubs that, for their part, are in engagement with balls in female splines or slots. A single helical spring within the belt-pulley structure forces the hubs apart in order thereby to increase the effective belt-pulley diameter. The belt pulleys are made symmetrical about the belt-pulley centre plane perpendicular to the axis of the belt pulley. In an exemplary embodiment, all of the belt-pulley parts with the exception of the spring and balls are formed in a conventional manner by simple sheet-metal stampings. Permanent assembly requires only external welding running in the circumferential direction or mechanical fastening, also in the circumferential direction, in the vicinity of the periphery of each driving pulley. In another exemplary embodiment, the stamped parts can alternatively be die cast or formed in some other way and welded together. Both exemplary embodiments of the belt pulley are particularly suitable for automated assembly and mass production. Likewise disclosed are centrifugal governing arrangements which can be fastened to the belt pulley to ensure that it operates at a constant speed irrespective of the input speed, and alternative hub and rim constructions for large-volume mass production and assembly with shafts.
|
