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:
Mar. 20, 2001
Filed:
Dec. 09, 1999
Toyoda Koki Kabushiki Kaisha, Kariya, JP;
Abstract
A vane pump is composed of a rotor that is rotatably disposed in a cam ring attached to a housing, a plurality of vanes that are slidably disposed in corresponding slits formed in the rotor in which the vane is projected from the slit upon rotation of the rotor, a pair of sidewall members that close both side portions of the cam ring to form a cavity defined by the cam ring and said sidewall members, a plurality of annular backpressure grooves that is depressively formed on contact surfaces of the sidewall members with the rotor in which adjacent two of the backpressure grooves are communicated with each other through a communication passage to introduce discharged pressure into an inside end portion of each of the slits, and depressions that are formed on at least one of the contact surfaces of the sidewall members with the rotor in which the depressions are not contacted with a part of side surface of each of the vanes.