| 摘要 |
PURPOSE:To aim at improved accuracy of machine processing of a main spindle bearing after cooling by regulating an air rate through an air discharge passage formed on a main spindle casting with a pressure regulator valve equipped on the passage, as well as by sending air to the bearing by means of installing an air blower on the main spindle between the bearings. CONSTITUTION:A blower front impellers 25 and an air blower rear impellers 26 are to be installed on a main spindle 2 to suck in by rotation of the main spindle 2 at a location between a front bearing 3 and a rear bearing 4, which support the main spindle 2 of a spindle stock 1, through an air suction passage 31, provided on a main spindle casing 5, a through hole 6 and an air suction passage 37, both provided on the main spindle 2. The air thus sucked in is sent to the front and rear bearings 3 and 4 and discharged from a front and rear ladyrinthes 22 and 23 prevent dust from entering as well as cooling the front and rear bearings 3 and 4. Also, the air flow rate is controlled independently to the respective front and rear bearings 3 and 4 at the slip stream side of both air blower impellers 25 and 26 by drilling an air discharge passages 35 on the main spindle casing 5 and installing pressure regulator valves 36a and 36b for the front and rear pressurized chambers, respectively, on the ends of these air discharge passages 35. By this method, accuracy of machine processing can be improved and deterioration of grease can be prevented.
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