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:
May. 24, 1994
Filed:
Oct. 28, 1992
Akihiko Yamamoto, Ibaraki, JP;
Toshihiro Yamada, Ibaraki, JP;
Tatsuo Natori, Kashiwa, JP;
Kotaro Naya, Shimizu, JP;
Motohiro Satoo, Ibaraki, JP;
Mitsuru Fujiwara, Ibaraki, JP;
Katsumi Matsubara, Ushiku, JP;
Kazuaki Shinoki, Shimizu, JP;
Hirotaka Kameya, Ibaraki, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A screw-type rotary fluid machine such as a compressor or a vacuum pump has male and female rotors which rotate within a casing, with or without mutual contact. At least one of the male and female rotors being surface-treated to have a treated surface structure. The treated surface structure is a multi-layered structures composed of a plurality of layers including a non-electrolytic Ni plating layer and at least one covering layer of organic resin. The organic resin may be one or more kinds selected from a group of engineering plastics, so as to improve mechanical strength.