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:
Sep. 12, 1989
Filed:
Dec. 13, 1988
Thomas M Atkins, Ann Arbor, MI (US);
Brian C Tuck, Ann Arbor, MI (US);
Edward N Fuller, Manchester, MI (US);
Peter Every, Livonia, MI (US);
Kelsey Hayes Company, Romulus, MI (US);
Abstract
A vehicle braking system such as an anti-lock brake system and/or a traction control utilizes a separate solenoid-actuated, two position, three-way valve in each controlled channel of the brake system for controlling the application of pressure to the respective wheel brake circuit. The valve includes a first port connected to the controlled wheel brake(s), a second port connected to an outlet of a hydraulic pump, and a third port connected to the inlet of the hydraulic pump. The valve is only moveable between a first position wherein the outlet of the pump is connected to the wheel brake to increase pressure to the wheel brake, and a second position wherein the wheel brake is connected to the inlet of the pump to decrease pressure to the wheel brake. An electronic control is provided for operating the valve to control the application of pressure to the selected wheel brakes. The control cyclically moves the valve between the first and second positions during a predetermined time period to alternately increase and decrease pressure to the wheel brake. More specifically, the control generates a pulse-width-modulated signal to modulate the time periods during which the valve is maintained in either the first or second positions to control the effective pressure to the wheel brake to obtain a net increase, decrease, or constant pressure to the wheel brake during the predetermined time period.