| 摘要 |
<p>An electric drive includes a driven ratchet base (17) rotatably mounted on a crank axle, a chain wheel (52) secured to the driven ratchet base to rotate therewith, a drive bevel gear (41) for rotating the driven ratchet base, a drive ratchet base (25) for rotating the driven ratchet base in one direction only and having a first engaging bevel gear (256), a ring element (23) secured on the crank axle to rotate therewith, two fixed axles (232) extending from the ring element each having a second engaging bevel gear (26) meshing with the first engaging bevel gear, a retaining bevel gear (27) meshing with the second engaging bevel gear and fixedly retained by the housing, and a torsion sensing device (30) for sensing the torsion exerted on the crank axle. <IMAGE></p> |
