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. 17, 1998
Filed:
Feb. 08, 1996
Louis C Harms, Evanston, IL (US);
Zilek Liberfarb, Morton Grove, IL (US);
Fluid Power Industries, Inc., Lincolnshire, IL (US);
Abstract
The technical field of the invention generally concerns electronically controlled valves for use in electro-hydraulically controlled transmissions. The valve 20 includes a hollow cage 42 pierced by tank ports 52, clutch ports 54, and by pump ports 56. The pump ports 56 receive fluid from a pump. The clutch ports 54 supply fluid to a hydraulic actuator. The cage clutch ports 54 supply fluid at a pressure that is proportional to an electrical control signal applied to a coil 252 of the valve 20. The tank ports 52 return fluid from the valve 20 to a tank. Located in the cage 42 is a main spool 112 that moves laterally relative to the cage 42 for controlling a flow of hydraulic fluid between the clutch ports 54 and either the pump ports 56 or the tank ports 52. An electro-magnetically operated pilot valve regulates a control pressure of fluid applied to a control pressure surface 138 at one end of the main spool 112. A feedback pressure passage 126, having a feedback restriction orifice 128, couples the pressure of fluid in the clutch ports 54 to a feedback pressure surface 114 at the opposite end of the spool 112. The orifice 128 restrains the rate at which fluid flows between the clutch ports 54 and the feedback pressure surface 114. One embodiment of the valve 20 includes a pressure spike suppression check valve 504 for relieving any abnormally high pressure that occurs in the clutch ports 54.