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:
Aug. 22, 2000
Filed:
Sep. 01, 1998
Tsutomu Okutomi, Kanagawa-ken, JP;
Mitsutaka Homma, Saitama-ken, JP;
Tsuneyo Seki, Tokyo, JP;
Atsushi Yamamoto, Tokyo, JP;
Takashi Kusano, Tokyo, JP;
Hiromichi Somei, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A vacuum valve which has a contact material having a constituent of high electrical conductivity such as Cu and an anti-arcing constituent including Cr in which particles whose particle size is in the range 0.1.about.150 .mu.m represent at least 90 volume %, and a ratio defined by the formula (.alpha..sub.900 -.alpha..sub.50).times.100/(.alpha..sub.900) for this contact material has a value of 8-12% and is the coefficient of thermal expansion of the contact material .alpha..sub.50 is the coefficient of thermal expansion of the contact material at 50.degree. C. The formation of channels generated at the interfaces of the Cr particles and the Cu matrix after undergoing the brazing step is suppressed, enabling the static withstand-voltage, contact resistance, and the breaking performance characteristics of the vacuum valve to be stabilized.