Drive unit for a motor-assisted bicycle.

摘要

A drive unit for a motor-assisted bicycle, having a driven portion manually including an axis of pedal crank (101) for transmitting a leg-power and a driven portion motor including a motor (M) to generate power assistance synthesized with a leg-power, wherein said drive unit (1) includes a case (70, 70L, 70R) which contains said manually operated portion and said driven portion motor that is made of resin by molding and having a supporting portion (90a, 91a, 92a) for mounting said case (70, 70L, 70R) in a vehicle body; characterized in that said case (70, 70L, 70R) rotatably supports the shaft (116) of said motor (M) and said pedal crank shaft (101); wherein a reinforcing member (105, 106, 107) is inserted in said hanger portion (90a, 91a, 92a) upon resin molding of said case and is connected to at least one of a plurality of other reinforcing members for reinforcing other parts, to form an integral reinforcing plate.