| 摘要 |
<p>A chuck includes a holder body, a clamp sleeve, and a large number of needle rollers. The holder body has a shank portion, a flange, and a chuck sleeve. The clamp sleeve is fitted onto the outer circumference of the chuck sleeve such that the clamp sleeve is rotatable and axially movable relative to the chuck sleeve. The needle rollers are disposed between the chuck sleeve and the clamp sleeve over the entire circumference. The clamp sleeve is rotated to cause the needle rollers to revolve spirally along the outer circumferential surface of the chuck sleeve while rotating about their own axes in order to decrease and restore the diameter of the chuck sleeve. A thrust member is disposed between the end surface of the flange opposite the shank portion and a corresponding end surface of the clamp sleeve.</p> |
