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:
Jul. 17, 2012
Filed:
Aug. 05, 2009
Ken Tanaka, Nukata-gun, JP;
Tsutomu Nakamura, Kariya, JP;
Kenji Takeda, Okazaki, JP;
Masaru Touge, Kariya, JP;
Yasuhiro Fukagawa, Obu, JP;
Ken Tanaka, Nukata-gun, JP;
Tsutomu Nakamura, Kariya, JP;
Kenji Takeda, Okazaki, JP;
Masaru Touge, Kariya, JP;
Yasuhiro Fukagawa, Obu, JP;
Denso Corporation, Kariya, JP;
Abstract
A power supply unit superimposes alternating-current voltage on direct-current voltage and applies it to a motor. As a result, when the motor is rotated, a current containing an alternating-current component flows. Further, the motor includes a capacitor connected in parallel with one phase coil. Owing to this capacitor, the impedance of the motor circuit between brushes is varied according to the rotation of the motor. Variation in impedance appears as variation in the amplitude of the alternating-current component in motor current. A signal processing unit extracts an alternating-current component from the motor current detected by the current detection unit and generates a rotation pulse corresponding to variation in the amplitude. A rotation angle detection unit detects the rotation angle of the motor based on this rotation pulse.