摘要 |
An object of the present invention is to provide a machine tool such as an internal surface grinding machine having two reversible spindles for providing shape which is stable with time to a workpiece by sufficiently cooling main spindles. The configuration of the machine tool is as follows: a cooling jacket (10) is provided around the outer circumferential surface of a main spindle (100), and inlet and outlet paths (12, 13) are provided in an index unit (5). The inlet and outlet paths (12, 13) can be reversed together with the main spindle (100) and are caused to vertically confront each other through a contrarotating central axis 01. The inlet and outlet paths (12, 13) and the cooling jacket (10) are connected to each other by means of connecting pipes (14). The connecting pipes (14) form a series of flow path leading from the inlet and outlet path (12) to the inlet and outlet path (13) through the cooling jacket (10). Cooling liquid enters the inlet and outlet path (12) and flows into the inlet and outlet path (13) through the cooling jacket (10) before the main spindle is reversed, while it flows reversely after the main spindle is reversed. The cooling liquid supplied to the cooling jacket (10) cools not only the main spindle (100) itself but also the vicinity of those protions constituting heat sources such as a bearing for the main spindle. The same configuration is given to a main spindle (200). <MATH> |