The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 16, 2003
Filed:
Feb. 26, 2002
Applicant:
Inventors:
Assignee:
Kabushiki Kaisha Toyota Jidoshokki, Kariya, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F04C 1/818 ; F04C 2/700 ; F16J 1/516 ;
U.S. Cl.
CPC ...
F04C 1/818 ; F04C 2/700 ; F16J 1/516 ;
Abstract
A Roots pump rotates a plurality of rotors by a pair of rotary shafts to draw gas. Each rotary shaft extends through a rear housing member of the Roots pump. An annular shaft seal is fitted around each rotary shaft and is received in a recess formed in the rear housing member. A helical groove is formed in a circumferential side of each rotary shaft. Each helical groove urges oil between the circumferential side of the associated shaft seal and the circumferential wall of the recess to move from a side corresponding to pump chambers toward a gear accommodating chamber when the associated rotary shaft rotates. This preferably prevents oil from leaking to the pump chambers.