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. 18, 1999
Filed:
Mar. 29, 1996
Katsuyoshi Shirai, Anjo, JP;
Satohiko Nakano, Chiryu, JP;
Aisin Seiki Kabushiki Kaisha, Kariya, JP;
Abstract
A rotational speed sensing device for sensing a rotational speed of a rotating member includes a pulsar ring having a plurality of wall portions, a permanent magnet, a coil, a first magnetic member and a second magnetic member. The first magnetic member is provided for forming a first magnetic circuit which includes at least the inner side of the coil. The first magnetic member has a plurality of projections that are alternately positionable during rotation of the pulsar ring in a first position in which the projections oppose the wall portions and in a second position in which the projections do not oppose the wall portions while the pulsar ring is rotating. The second magnetic member is provided for forming a second magnetic circuit which does not include the inner side of the coil in such a manner that the magnetic resistance of the second magnetic circuit is lower than the magnetic resistance of the first magnetic circuit when the projections are located in the second position.