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:
Oct. 20, 2015
Filed:
Nov. 15, 2012
Aisin Seiki Kabushiki Kaisha, Kariya-shi, JP;
AISIN SEIKI KABUSHIKI KAISHA, Kariya-Shi, Aichi, JP;
Abstract
In order to realize, without inviting cost increase, a control for maintaining a pressure of fluid delivered from a pump at a target value, a pump control unit is provided with a driver control unit controlling a rotational speed of a hydraulic pump through adjustment of a duty ratio of a PWM signal driving excitation coils of an electric motor. Further, the pump control unit is provided also with a signal correction circuit configured to convert a current flowing in the excitation coils to a voltage signal with using a shunt resistor and to divide the voltage signal with using a voltage division ratio setting circuit and to shorten an ON signal of the PWM signal by increasing the divided voltage. The voltage division ratio setting circuit has a characteristics of setting the divided voltage higher, the longer an ON period of the PWM signal.