摘要 |
A ratchet gear device is applied for a bicycle rear wheel having a wheel axle and a hub mounted on the wheel axle, and the ratchet gear device has a freewheel, a collar, a ratchet ring and at least one permanent magnet. The freewheel is mounted around the wheel axle and has multiple wedging teeth. The collar is magnetic, is mounted securely in the hub and has multiple engaging teeth. The ratchet ring is mounted in the collar and has multiple engaging slots and multiple ratchet teeth. The engaging slots engage the engaging teeth in the collar. The ratchet teeth engage the wedging teeth on the freewheel. The at least one permanent magnet is attached to the ratchet ring to provide a magnetic force to move the ratchet ring to an engaging position where the ratchet teeth engages the wedging teeth on the freewheel.
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