Patent ID: 9676039
Date: 2017-06-13
CPC Classifications: B23B,Y10T

Claim:
1. A tool holder having a chuck section that grasps an cutting tool at a leading side and a shank section that is at a trailing side of the tool holder, comprising: a holder body that is composed with a main body and a distal extending portion ( a sleeve, which has an annular shape and is a physically separated part from the holder body, disposed at the leading side of the holder body and capable of deforming in a radial direction with respect to the rotational axis for grasping the grasped cutting tool through an action of a pressure medium, the sleeve having a trailing portion that is at the trailing side and that is inserted inside the distal extending portion in a predetermined length in order to be secured therein; a support portion, which has an annular shape and is a physically separated part from the holder body and the sleeve, disposed over the sleeve in the radial direction such that a contacting portion with the sleeve is at the leading side and distant from the distal extending portion of the holder body in the rotational axis; and a pressure chamber provided circumferentially between the support portion and the sleeve, wherein the main body of the holder body includes a pressure guide passageway for transmitting a pressure through the pressure medium to the pressure chamber, a pressure-medium storage space has an annular shape and is formed in a space sandwiched in the rotational axis by a part of the holder body, which faces the leading side, and a part of the support part, which faces the trailing side, the pressure-medium storage space positioning between the pressure guide passageway and the pressure chamber in the rotational axis, a communication passageway, which has an annular shape around the rotation axis and through which the pressure medium commutes, is formed to annularly connect the pressure-medium storage space with the pressure chamber, the communication passageway is located outer than the pressure chamber in the radius direction, a section in the rotational axis where the distal extending portion exists is defined as a distal section (DS), and the distal extending portion of the holder body, the sleeve and the support portion are layered in the radial direction within the distal section.