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. 15, 1994
Filed:
Sep. 14, 1993
Hitachi, Ltd., Tokyo, JP;
Abstract
A method of producing an oil-free screw compressor has the following steps: preparing a semi-finished metallic female rotor which has a spiral profile, and a semi-finished metallic male rotor which has a spiral profile; forming a metallic coating film containing particles of grinding material on the surface of the semi-finished female rotor; forming, on the surface of the semi-finished male rotor, a coating film of a material softer than the metallic coating film on the female rotor; grinding the surfaces of the semi-finished rotors into predetermined configurations; mounting the ground rotors on bearings so that the rotors are assembled in a rotor casing with a substantially constant spacing held between the axes of the semi-finished rotors; mounting timing gears on the rotors so as to drivingly connect the rotors each other; and driving the rotors by driving means while restraining the back lash in the rotating direction by means of the timing gears and applying a compression load to the rotors so that the coating film on the female rotor grinds and generates the coating film on the surface of the male rotor, thereby completing profiling of the male rotor and establishing a desired minimum gap between both rotors.