Patent ID: 8672103

Claim:
A main shaft drive for a machine tool, comprising: a rotation resistance applying device that applies rotation resistance to a main shaft by causing a pressing surface of a pressing member to press-contact a friction surface of a press member when the main shaft is rotationally driven, the main shaft being rotatably supported by a frame; a supplying device provided at a side of the frame, the supplying device supplying lubricant to the rotation resistance applying device; a nozzle hole for supplying the lubricant; a supplying circuit provided at at least one of the side of the frame and a side of the main shaft, the supplying circuit connecting the supplying device and the nozzle hole to each other; and a supply groove for the lubricant, the supply groove being provided so as to open to at least one of the friction surface and the pressing surface, wherein the nozzle hole opens towards the supply groove, and wherein the supply groove extends so as to surround the main shaft within a range where the friction surface and the pressing surface oppose each other, and wherein the supply groove includes a section that is provided by at least a part of the supply groove and that intersects a circumference in which a rotational center of the main shaft is a center, and a discharge opening that is connected to a location that is outside the range where the friction surface and the pressing surface oppose each other.