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. 18, 2002
Filed:
Jul. 25, 2001
Louis C. Harms, Evanston, IL (US);
Zilek Liberfarb, Morton Grove, IL (US);
Parker-Hannifin Corporation, Cleveland, OH (US);
Abstract
This invention generally concerns electronically controlled hydraulic valves for use in electro-hydraulically controlled transmissions. The proportional pressure control valve includes a hollow cage pierced by cage tank ports , cage clutch ports , and cage pump ports . The cage pump ports receive fluid from a pump. The cage clutch ports supply fluid to a hydraulic actuator. The cage tank ports return fluid from the valve to a tank from where fluid circulates back to the pump. Main spool controls fluid flow between cage clutch ports and cage pump ports or cage tank ports . An electro-magnetically operated pilot valve regulates fluid pressure applied to a control pressure surface . A feedback pressure passage , having a feedback restriction orifice , restrains the rate fluid flows between the cage clutch ports and the feedback pressure surface .