| 摘要 |
PURPOSE:To prevent the degree of accuracy from deteriorating due to the rise of temperature and as well to prevent a drop in insulation due to water leakage, by circulating cooling gas in a magnetic chuck. CONSTITUTION:A thermally-insulated gas inflow pipe 2 for feeding cooling gas into a magnetic body 1 is connected through an inlet nipple 20 to the body 1 at one side thereof, and a gas discharge pipe 3 for discharging cooling gas from the body 1 is connected through a discharge nipple 30 to the body 1 on the other side thereof. Cooling gas is fed into the magnetic body 1 through the gas inflow pipe 2 by means of a cooling and circulating device 4 to cool the magnetic chuck. Heated cooling gas returns through the discharge pipe 3 to the cooling and circulating device 4 where the heated gas is cooled down and then is again fed into the body 1 therefrom. The cooling and circulating device 4 controls the flow of cooling gas in accordance with a temperature signal from a temperature sensor which is not shown, through a feed-back circuit 5. With this arrangement, heat generation from a chuck coil and heat generated in grinding from the outside may be prevented, thereby the degree of accuracy in the magnetic chuck may be maintained. |
