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:
Apr. 14, 1992
Filed:
Oct. 16, 1990
Akihiro Ohno, Okazaki, JP;
Kazumasa Kodama, Okazaki, JP;
Yoshiharu Amano, Toyota, JP;
Yukio Okamura, Toyota, JP;
Toyoda Koki Kabushiki Kaisha, Kariya, JP;
Abstract
A power steering apparatus wherein a heated state of the electric motor is detected without employing any temperature sensor. There are previously stored plural temperature characteristics each representing the relationship between the temperature variation caused per unit time in the electric motor and the load current, which are prepared, for plural motor temperatures or plural differences between the motor temperature and the ambient temperature. A temperature characteristic is selected on the basis of the present predicted motor temperature or the difference between the motor temperature and the ambient temperature. The present load current is detected, and the temperature variation caused per unit time correspondingly to such load current is calculated from the selected temperature characteristic. The unit-time temperature variations thus obtained are integrated with the lapse of time to predict the present motor temperature. Upon rise of the predicted motor temperature beyond a predetermined point, the electric motor is considered to be in a heated state.