Patent ID: 8127909

Claim:
A hub assembly for a bicycle, comprising: a shaft ( 12 ); a hub body ( 40 ) rotatably mounted on the shaft; a driven ring ( 43 ) secured in the hub body and having an inner wall provided with a plurality of oneway ratchet teeth ( 42 ); a drive seat ( 10 ) rotatably mounted on the shaft; a drive ring ( 13 ) secured on the drive seat and having a periphery provided with a plurality of pressing grooves ( 131 ); a rotation ring ( 20 ) mounted on the drive ring and having a periphery provided with a plurality of receiving slots ( 21 ); a plurality of pawl members ( 22 ) each pivotally mounted in a respective one of the receiving slots of the rotation ring to releasably mesh with the oneway ratchet teeth of the driven ring; a plurality of push balls ( 23 ) each movably mounted on the rotation ring and each biased between a respective one of the pressing grooves of the drive ring and a respective one of the pawl members to push the respective pawl member toward the oneway ratchet teeth of the driven ring; a mounting sleeve ( 32 ) mounted on the shaft; a damping ring ( 30 ) mounted on the mounting sleeve and attached to the rotation ring to damp a rotation movement of the rotation ring; a plurality of tension adjusting mechanisms ( 37 ) each biased between the damping ring and the mounting sleeve to adjust a damping force of the damping ring; wherein each of the receiving slots of the rotation ring has a first end provided with a receiving bore ( 212 ) connected between the drive ring and each of the receiving slots; each of the push balls is movably mounted in a respective one of the receiving bore of the rotation ring and has a first side received in and pressed by the respective one pressing groove of the drive ring and a second side abutting the respective pawl member; the rotation ring is provided with a plurality of positioning pieces ( 27 ); the damping ring has an outer wall provided with a plurality of positioning recesses ( 31 ) to fix the positioning pieces of the rotation ring respectively; the damping ring has a periphery provided with a plurality of threaded receiving holes ( 33 ) connected to the mounting sleeve to receive the tension adjusting mechanisms respectively; each of the tension adjusting mechanisms includes: a pressing ball ( 34 ) movably mounted in the respective receiving hole of the damping ring and pressing an outer wall of the mounting sleeve; an adjusting screw ( 36 ) screwed into the respective receiving hole of the damping ring; and a push spring ( 35 ) mounted in the respective receiving hole of the damping ring and biased between the pressing ball and the adjusting screw; the hub body has an inner portion provided with a receiving space ( 41 ) to receive the rotation ring and the damping ring.