CHUCK DEVICE

To fix a work piece so as to prevent generation of bending force on the work piece.SOLUTION: A chuck device includes: a chuck body; a collet having three or more grip portions which are provided inside the chuck body, and have an outer peripheral surface being a tapered surface, and an inner peripheral surface contacting a work piece; a restricting member disposed outside the collet and having an inner peripheral surface being a tapered surface contacting the outer peripheral surfaces of the grip portions; and a cylinder provided in the chuck body and moving the collet relative to the restricting member in a direction along a center axis. A cross-sectional shape of each grip portion when the inner peripheral surface of the grip portion is cut by a plane passing through a center axis of the collet, is a curve in which a side contacting the work piece is convex.SELECTED DRAWING: Figure 1 【課題】ワークに曲げ力が発生しないようにワークを固定する。【解決手段】チャック装置は，チャック本体と，前記チャック本体の内側に設けられた３以上の把持部であって，テーパー面である外周面と，ワークに接触する内周面とを有する把持部を有するコレットと，前記コレットの外側に配置され，前記把持部の前記外周面と接触するテーパー面である内周面を有する規制部材と，前記チャック本体に設けられ，前記コレットを前記規制部材に対し中心軸に沿った方向に相対移動させるシリンダと，を備え，前記把持部の前記内周面を前記コレットの中心軸を通る平面で切ったときの断面形状は，前記ワークに接触する側が凸となる曲線である。【選択図】図１