VARIABLE DIAMETER GEAR DEVICE AND VARIABLE TRANSMISSIONS USING SUCH DEVICES

摘要

A variable diameter gear device for use in a variable ratio transmission system includes a gear tooth set deployed around an axle which defines an axis of rotation. The gear tooth set includes at least two displaceable gear tooth sequences, each including a multiple gear teeth spaced at a uniform pitch, and a diameter changer mechanically linked to the axle and to the gear tooth set. The diameter changer is deployed to transfer a turning moment between the axle and the gear tooth set, and to displace the gear tooth set so as to vary a degree of peripheral coextension between the gear tooth sequences. Specifically, the diameter changer transforms (he gear device between at least two states in which the gear tooth set is deployed to provide an effective cylindrical gear with differing effective numbers of teeth. The gear device may be used either in direct engagement with another- gear wheel or as part of a chain-based transmission system.