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:
Jun. 16, 1992
Filed:
Nov. 05, 1990
Frederick J Adams, Avon, GB;
TRW Cam Gears Limited, Avon, GB;
Abstract
A power assisted vehicle steering system of the speed responsive kind has a ram 6 fluid flow to chambers 4 and 5 of which from a pump 9 is directed by an open center steering valve 1. Communication between the chambers 4 and 5 is permissible through a by-pass valve 13 adjustable by a solenoid 17 in response to vehicle speed to open such communication as speed increases (and thereby decrease power assistance) and vice versa. The valve 13 has a spool 22 which is spring loaded relative to a control spindle 18 of the solenoid. Adjustment of the spool 22 in response to speed variations opens or closes by-pass ports 14 and 15 to opposite ends of a restrictor 32 which provides such fluid flow communication. A spring loaded spool 41 in the valve 13 is responsive through chambers 39 and 40 to fluid pressure at opposite sides of the restrictor 32. When the fluid pressure differential across the restrictor 32 exceeds a predetermined differential, the spool 41 is displaced to direct fluid pressure to spool chamber 55. This displaces the spool 22 against its spring biasing 27 and relative to the rod 18 thereby closing the ports 14 and 15 (and communication between the ram chambers) so that increased power assistance becomes available irrespective of the vehicle being at high speed.