LATHE AND SPINDLE UNIT FOR MILLER

PROBLEM TO BE SOLVED: To provide a tool motor spindle having a small structure that is simplified as much as possible.SOLUTION: A spindle unit for a machine tool includes a processing spindle 1, which is rotatably supported by and attached to spindle bearings separated in an axial direction, and an electric driving motor in a spindle case 2. The processing spindle includes: a tool clamp device 8 located at the head side; a non-rotary ring cylinder 10 which is located at the rear side and operates the clamp device 8 through a rotary tie rod 9; and a rotary bush 16 which supplies a coolant and/or a lubricant to a tool through a hydraulic line 4 which penetrates through the processing spindle 1 in a longitudinal direction. At least a part of the non-rotary ring cylinder 10 is housed in a rear end part of the processing spindle 1. 【課題】可能な限り単純化された小型の構造体を呈する工具モーター主軸を提供する。【解決手段】主軸ケース２内で、軸方向に離間した主軸軸受において回転的に軸受取付けされている加工主軸１と、電動駆動モーターとを備える工作機械用主軸ユニットを提供する。この加工主軸は、ヘッド側に、工具用のクランプ装置８と、後側に、回転タイロッド９を介して上記クランプ装置８を作動させる非回転リングシリンダー１０と、上記加工主軸１を長手方向に貫通する油圧管路４を通して、上記工具に冷却剤及び／又は潤滑剤を供給する回転ブシュ１６とを含む。少なくとも上記非回転リングシリンダー１０の一部が上記加工主軸１の後端部に収まる。【選択図】図１