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. 20, 2001
Filed:
Nov. 09, 1999
Hitoshi Oyama, Itami, JP;
Koichi Hashida, Itami, JP;
Sumitomo Electric Industries, Inc., Osaka, JP;
Abstract
A proportional pressure control valve of the type in which a spool is driven by an electromagnet to control the load pressure to a value corresponding to the electromagnet energizing current is provided to simplify and reduce the cost of such valve. The number of springs has been reduced to one by biasing the spool with a spring through an actuating element of the electromagnet. Also, by providing a reaction force piston near a low-pressure pressure chamber, the need to form a hole in the actuator at a functionally important portion has been eliminated. Furthermore, arrangement is such that the load pressure acts on the spool in the same direction with the force of the electromagnet to supplement it. Further, the actuating element is formed integrally with the spool to eliminate any sliding portions from the actuating element, and a gap is formed between the actuation element and the member surrounding the actuating element to reduce the sliding resistance thereof.