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:
Mar. 19, 1996
Filed:
Nov. 07, 1994
Malcolm J McArthur, Escondido, CA (US);
Harvey Jansen, Tempe, AZ (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
Problems such as slow frequency response and low reliability when operating with contaminated fluids of variable viscosity are alleviated in a low pressure hydraulic system (10) which utilizes a single stage, electro-hydraulic, clevis-type pressure control valve (40). The valve (40)includes a control piston (106) referenced to a control pressure within a control pressure cavity (60) to provide a feedback of control pressure which converts the valve (40) from an integral to a proportional control device, thereby enhancing stability of the hydraulic system (10). Compensation for changes in fluid viscosity, as a result of changes in fluid temperature, is provided by fabricating a bifurcated portion (98) and/or a metering bridge portion (62) of the valve (10) from materials having dissimilar coefficients of thermal expansion. Exemplary embodiments of a hydraulic system (10) suitable for use in either vehicular or stationary applications involving pressure actuated devices, such as a clutch (16), automatic transmissions or anti-lock brakes, are provided.