PURPOSE: To prevent clogging of various types of piping and the like due to corrosion inside a cooling water passage in a lubricating oil reservoir constituted of a bearing case for housing a bearing for supporting a rotation shaft by incorporating a tube of a corrosion resistant material as a cooling water passage in the bearing case.
CONSTITUTION: In a vacuum pump, a pair of rotating bodies 2 engaging with each other are arranged in a casing 1 and bearings 5, 6 to rotating-support respective rotating bodies 2 are housed respectively in bearing cases 10, 11. The bearing cases 10, 11 are respectively serving also as lubricating oil reservoirs, and lubricating oil 38 is housed therein at a predetermined level being a level for submerging an outer circumferential surface of gears 8. In this case, a tube 15 formed of a stainless tube and the like and made of a corrosion resistant material is insert-molded integrally with each of the bearing cases 10, 11 at each bottom of the bearing cases 10, 11. Stainless pipes 17 for a cooling water supply passage are connected to both ends of each tube 15 to flow cooling water in each tube 15 so as to cool the bearing cases 10, 11.
OGAMINO HIROAKI
MURAKAMI SEIGO
USUI KATSUAKI
