Patent ID: 6824491
Filing Date: 2004-11-30
Classification: F16H

Abstract:
A power transmission device comprising:a frame having a plurality of slots defined through a wall thereof, a plurality of axial grooves defined through the wall of the frame, a plurality of protrusions extending from an inside surface of the frame and a ridge defined on an outer surface of the frame; a transmission mechanism comprising a shifting gear having inner teeth engageable with first planet gears and second planet gears, the first planet gears having outer teeth and the shifting gear having an annular groove defined in an outer periphery thereof, a plurality of notches defined in the outer surface of the shifting gear so as to engage with the protrusions of the frame; a torque feedback mechanism comprising a pushing wheel and a sliding ring, each of the sliding ring and the pushing wheel having a plurality of inclined faces, a C-shaped clamp and a compression spring which is mounted to the frame and limited between ridges of the frame and the clamp, the sliding member having ribs which are inserted in the axial groove of the frame so that the sliding ring is movable axially along the axial groove, the clamp having a plurality of pins extending through the slots of the frame and engaging the annular groove of the shifting gear so as to selectively restrain the shifting gear in a first position and engaging the first planet gears and the second planet gears, and selectively restrain the shifting gear in a second position and only engaging the second planet gears; wherein when the pushing wheel is rotated, the inclined faces of the pushing wheel drive the inclined faces of the sliding ring which pushes the shifting gear and drives the compression spring so as to generate axial force; wherein when the shifting gear is in the first position, the shifting gear co-rotate with the first planet gears and the second planet gears; and wherein when the shifting gear is in the second position, the notches of the shifting gear engage the protrusions of the frame for rotatably fixing the shifting gear.