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:
Nov. 13, 2001
Filed:
Oct. 26, 1999
Manabu Nonaka, Narashino, JP;
Akira Yamauchi, Narashino, JP;
Seiko Instruments Inc., , JP;
Abstract
A vacuum pump comprises an inlet port into which a gas is introduced, an outlet port from which the gas is discharged, a stator, a motor, and a rotor opposing the stator and driven by the motor to undergo rotation to cooperate with the stator to force the gas from the inlet port to the outlet port. The rotor has a body, a spiral thread disposed on the body, and a thread groove disposed between adjacent lines of the spiral thread. An axial length of the spiral thread is shorter than an axial length of the rotor so that a terminal end portion of the spiral thread terminates short of an axial end of the rotor. The terminal end portion of the spiral thread slopes inward toward a surface portion of one of the thread grooves. A junction surface between a terminal end portion of the slope of the spiral thread and the surface portion of the thread groove forms a recessed portion.