PURPOSE: To feed an amount of gas necessary enough to cool a motor to the peripheral part of a motor, to prevent the increase of a coil temperature, and to improve reliability by providing a regulation valve to control the flow of gas sucked in a closed container according to the numbers of revolutions of a motor and a compression mechanism.
CONSTITUTION: On a condition that the coil temperature of a motor 7 is not increased so much, an adjusting valve 27 is switched to a direction as shown, and low pressure gas is guided to the interior of a closed container 1 through a main suction pipe 25. In which case, most of low pressure gas is sucked directly in a compression mechanism 2 through the suction port 21 of a bearing part 4. Meanwhile, on a condition that the coil temperature of the motor 7 is rapidly increased, low pressure gas is guided through an auxiliary suction pipe 26 to the interior of the closed chamber 1 through an auxiliary suction pipe 26. In which case, after most of low pressure gas flows from a position below the motor 7 through communication holes 28 and 29 and a gap between the closed container 1 and stator 7b and a gap between a rotor 7a and the stator 7b, it is sucked in a compression mechanism 2 through the suction port 21 formed in the bearing part 4, whereby the motor 7 is sufficiently cooled.
HARADA TERUMARU
NISHIWAKI FUMITOSHI
SHINTAKU HIDENOBU
NAKADA HIDEKI
