| US 7,458,790 B2 | ||
| Vacuum pump with improved oil lubrication | ||
| Shinya Yamamoto, Kariya (Japan); Ryosuke Koshizaka, Kariya (Japan); Yuya Izawa, Kariya (Japan); Masahiro Inagaki, Kariya (Japan); and Kentaro Ishihara, Kariya (Japan) | ||
| Assigned to Kabushiki Kaisha Toyota Jidoshokki, Kariya-Shi (Japan) | ||
| Filed on Oct. 31, 2006, as Appl. No. 11/591,077. | ||
| Claims priority of application No. 2005-318583 (JP), filed on Nov. 01, 2005. | ||
| Prior Publication US 2007/0098585 A1, May 03, 2007 | ||
| Int. Cl. F03C 2/00 (2006.01); F04C 2/00 (2006.01); F04C 27/02 (2006.01) | ||
| U.S. Cl. 418—88 [418/94; 418/102; 418/201.1; 184/6.16; 184/6.18; 384/462; 384/474] | 11 Claims |
| 1. A vacuum pump comprising:
a housing assembly having an oil-reservoir chamber in which a lubricating oil is stored;
a pair of screw rotors disposed in the housing assembly and engaged with each other;
a pair of rotary shafts connected to the rotors, respectively;
a plurality of bearings supporting each of the rotary shafts and having an opening;
an oil-feed pump for feeding the lubricating oil from the oil-reservoir chamber to the bearing;
an oil-circulation passage provided for circulating the lubricating oil from the oil-feed pump to the oil-reservoir chamber
through the bearing;
a cover provided at the opening of the bearing to close the opening of the bearing with a clearance remained, the cover permitting
the lubricating oil to enter the bearing through the clearance; and
an oil-escape passage provided adjacent to the bearing for returning to the oil-reservoir chamber the lubricating oil not
entering the bearing.
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