| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively provide a structure provided with a belt groove with being offset toward a side provided with one support bearing without reducing durability. SOLUTION: An average diameter of an inner peripheral surface of a sleeve 8a in a part where an inner ring 23 forming one support bearing 21a is externally fitted and secured is made larger than an average diameter r8a of the inner peripheral surface of the sleeve 8a in a part where the inner ring 23 forming the other support bearing 21b is externally fitted and secured. An outer diameter R7b of a driven pulley 7b in a part where an outer ring 25 forming the support bearing 21b is internally fitted and secured is made smaller than an average diameter =(D1+D2)/2} in a part having a belt groove 18 formed in an outer surface of the driven pulley 7b. |
