POWER TRANSMITTING SYSTEM FOR BICYCLE, AND PULLEY FOR BICYCLE

摘要

PROBLEM TO BE SOLVED: To prevent occurrence of abnormal sound or occurrence of jumping when tension of a toothed belt increases. SOLUTION: A pulley tooth space section 14 and a pulley tooth section 12 of a driving pulley are constituted by four circular arcs pairing with each other on both sides of the center line Y'. The third circular arc B6 and part of the second circular arc B5 connecting to the third circular arc B6 are formed so that the clearance between a power transmission surface of the pulley tooth section and a power transmission surface of a belt tooth section of the toothed belt 30 is secured to have a predetermined size to reduce interference with the toothed belt. A pulley tooth space section and a pulley tooth section of a driven pulley are also constituted by four circular arcs pairing with each other on both sides of the center line. The circular arc of the driven pulley corresponding to the fourth circular arc B7 of the driving pulley is formed so that the groove depth of the pulley tooth space section of the driven pulley is longer than tooth height of the belt tooth section. COPYRIGHT: (C)2005,JPO&NCIPI