| 摘要 |
PURPOSE:To markedly increase the operation time of a machine tool by permitting the position in the direction of the spindle of a tool to be stabilized in a short time by feeding coolant through the delay by a proper time after the start of operation of the rotary shaft on the spindle. CONSTITUTION:A spindle 1 turns a diamond wheel 2, forming a static pressure gas bearing spindle. Two stripes of screw grooves for allowing coolant to pass are formed on the outer peripheral part of a bearing housing 27 in which journal bearing parts 21a-21d are built-in. A sleeve 28 is applied onto the outer periphery of the groove to form a cooling passage 29, and the colant enters from a feeding port 30 and goes to a discharge port 31. A proper time for feeding water from the operation start time of a rotary shaft 25 is set in a timer 37, and when the set time lapses, a solenoid valve 36 is opened by the operation of the timer 37, and the water is introduced through the cooling passage 29 and reaches a recovery part 41, and thus the rise of temperature is suppressed by the cooling effect of the spindle 1. |
