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. 04, 1993
Filed:
Feb. 27, 1992
Nobuyuki Yamashita, Hitachi, JP;
Kazuo Tahara, Hitachi, JP;
Akio Chiba, Hitachi, JP;
Masahisa Sobue, Mito, JP;
Toshimi Abukawa, Hitachiota, JP;
Shin'ichi Sakamoto, Hitachi, JP;
Shun Suzuki, Katsuta, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Koki Co., Ltd., Tokyo, JP;
Abstract
Ceramics material are not resistant to tensile force, though they are resistant to compression force. Therefore, ceramics materials, when used as the material of a commutator of an electric rotary machine, tends to be cracked and broken due to tensile stress generated in the inner peripheral portion of the commutator when the latter is press-fitted on the rotor shaft of the machine. The invention is aimed at obviating the above-described problem, so as to make it possible to produce a sliding current collector of an electric rotary machine from a ceramics material. To this end, according to the invention, an annular gap is formed between the inner peripheral surface of the ceramics commutator and the other peripheral surface of the rotary shaft and the gap is filled with a resin such as a thermosetting resin which is then thermally set to form a resin layer by which the commutator is bonded to the rotor shaft. The resin layer effectively absorbs any tensile stress which may otherwise be caused in the inner peripheral portion of the commutator due to, for example, thermal expansion of the rotor shaft. It is thus possible to securely fix the commutator to the rotor shaft without risk of cracking or damaging of the commutator.