Abstract
Keywords:
ISCVT, CVT, continuously variable transmission, bicycle, traction drive
Abstract
A new continuously variable transmission for bicycles(B-CVT) was developed. The B-CVT has a new mechanism of the traction drive transmitting power through contacts between inner sphere and outer sphere. In general, a continuously variable transmission for bicycles is required to have high efficiency in power with the large torque capacity and the packageability in a narrow space. The B-CVT can be installed in the side space of rear wheel. Due to inner-outer spherical contact, the B-CVT can get above 90% power efficiency in whole range of speed ratio with satisfying the packageability. A simple chain-sprocket without shifting device is used. The device changing speed ratio is controlled by hand. A prototype of the optimal design was manufactured. The accelerating ability, the gradeability and the improved driveability are evaluated by the road test.