SCREW-TYPE FLUID MACHINE

摘要

A vacuum pump has rotating shafts individually connected to a pair of screw-like rotors and also has a pair of shaft holding bodies extending in the housing. The shaft holding bodies support the rotating shafts by base bearing sections and end bearing sections. Each pair of the base bearing section and the end bearing section is fixed in the axial direction relative to a corresponding rotating shaft and shaft holding body. Lubricant oil is contained in a oil containing space in a gear case attached to the housing. A cooling water path in which cooling water for cooling the lubricant oil flows is formed in the gear case. An electromagnetic valve controls the flow rate of the cooling water in the cooling water path. A temperature sensor is provided in the oil containing space and measures the temperature of the lubricant oil. According to the temperature measured by the temperature sensor, a control device controls the magnetic valve in order that the temperature of the lubricant oil in the oil containing space is maintained constant. Application of an axial load on the bearing sections is suppressed even if the bearing sections are fixed in the axial direction to the rotating shafts and the shaft holding bodies.