| 摘要 |
PURPOSE:To enable the minimizing of the thermal displacement of a head stock by causing air suction through a suction port continuous to the head stock inside, and air discharge through an exhaust port continuous from the head stock inside to the atmosphere. CONSTITUTION:The rotation of a driving shaft 6 driven by a motor 9, is transmitted to a main shaft 5 via gears 7 and 8, and this main shaft 5 begins to rotate. With the rotation of the aforesaid shafts 5 and 6, bearings 10-15 and the gearing part of the gears 7 and 8 are heated and in particular, the bearings at the main shaft of larger diameter are heated by friction with air in a head stock 16, as well. On the other hand, however, the rotation of the gear 8 causes an air flow in a casing 17 and the outside air of low temperature is sucked into the casing 17 through its suction port 20. Concurrently, the rotation of the gear 7 discharges air from the casing 17 through its exhaust port 19. As a result, the inside of the casing 17 is exposed to effective heat exchange with the atmosphere and cooled. |
