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:
Nov. 25, 1986
Filed:
Aug. 30, 1984
William L Kelledes, Brighton, MI (US);
Walter K O'Neil, Birmingham, MI (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
An electrical power assisted steering system for a vehicle. The system includes a battery, having two terminals at different voltages and a center tap, and a bidirectional electric power assist motor having two terminals, one terminal being connected to the center tap of the battery. In an electric vehicle, said battery would be the traction battery. A control circuit responds to movement of the vehicle's steering wheel to generate a pulse width modulated (PWM) signal to drive the motor to assist in steering. The pulse widths are directly proportional to the driver's rotational displacement of the steering wheel and the amount of current flowing through the motor and inversely proportional to the speed of the vehicle. The PWM signal is applied to a selected one of two driving transistors, the first of which is connected between one of the terminals of the battery and the free terminal of the motor, the other of which is connected between the other terminal of the battery and the free terminal of the motor. Upon receipt of the PWM signal, the selected driving transistor connects the motor to its associated terminal of the battery to cause the motor to turn in a desired direction and deliver torque proportional to the width of the pulses. Also disclosed are monitoring circuits which monitor the operation of the control circuit and disconnect the motor from the battery when a malfunction is detected.