stopping groove are formed in the outer peripheral surface of the cylindrical component 116 a pressure ring 117 is mounted around the outside of the cylindrical component 116 as shown in fig2 the pressure ring 117 which is nonrotatably supported on the cylindrical component 116 while allowed to move in the axial direction is allowed to come into contact with the lock ring 114 in addition a pressure nut 118 is screwed on the outer periphery at the left end of the cylindrical component 116 a coned disk spring 119 is disposed between the pressure nut 118 and the pressure ring 117 the pressure exerted by the coned disk spring 119 can be adjusted by adjusting the fastening of the pressure nut 118 the frictional force between the lock ring 114 and the flange component 115 of the moving member 103a can be adjusted via the pressure ring 117 and the rotation of the hub shell 43 can be controlled arbitrarily for example maximizing the frictional force produced by the coned disk spring 119 makes it possible to bring the system into a locked state with minimal rotation of the hub shell 43 furthermore reducing the frictional force weakens the force with.