Abstract: A vacuum pump draws gas by operating a gas conveying body in a pump chamber through rotation of a rotary shaft. The vacuum pump has an oil housing member, a stopper and a circumferential wall surface. The oil housing member defines an oil zone adjacent to the pump chamber. The stopper has a circumferential surface. The stopper is located on the rotary shaft to rotate integrally with the rotary shaft and prevents oil from entering the pump chamber. The center of curvature of the circumferential wall surface coincides with that of the rotary shaft. The circumferential wall surface surrounds at least a part of the circumferential surface of the stopper that is above the rotary shaft. The circumferential wall surface is inclined such that the distance between the circumferential wall surface and the axis of the rotary shaft decreases toward the oil zone.

Abstract: A vacuum pump draws gas by operating a gas conveying body in a pump chamber through rotation of a rotary shaft. The vacuum pump has an oil housing member, a stopper and a circumferential wall surface. The oil housing member defines an oil zone adjacent to the pump chamber. The stopper has a circumferential surface. The stopper is located on the rotary shaft to rotate integrally with the rotary shaft and prevents oil from entering the pump chamber. The center of curvature of the circumferential wall surface coincides with that of the rotary shaft. The circumferential wall surface surrounds at least a part of the circumferential surface of the stopper that is above the rotary shaft. The circumferential wall surface is inclined such that the distance between the circumferential wall surface and the axis of the rotary shaft decreases toward the oil zone.

Abstract: A cooling apparatus, for cooling a vacuum pump, in which a cooler 44 is arranged on a rotor housing 12, a cooler 45 is arranged on a rear housing 14 and a drive unit 33, a cooler 46 is arranged on a controller 37, a cooler 47 is arranged on an inverter 38, and a cooler 48 is mounted on the peripheral surface of an electric motor M is disclosed. The coolers 46, 47, 48 are arranged midway in a main supply pipe 49. The coolers 44, 45, on the other hand, are arranged midway in a subsidiary supply pipe 50. The energization and deenergization of an electromagnetic three-way valve 51 arranged at the diverging point of the main supply pipe 49 and the subsidiary supply pipe 50 is controlled by the controller 37.