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:
Dec. 31, 2002
Filed:
May. 24, 2001
Hiroaki Kitamoto, Komatsu, JP;
Kaoru Hasegawa, Tatsunokuchi-machi, JP;
Kenjiro Shimada, Komatsu, JP;
Komatsu Ltd., Tokyo, JP;
Abstract
Hydraulic pressure is controlled, which has such advantages that a generation of peak pressure (shoot pressure) can be lowered, mis-operation due to biting of particles can be reduced, or the cost thereof can be reduced. First, a large amount inflow command current is supplied to a proportional solenoid from a time point t to a time point t . Consequentially, pilot pressure rises in a pilot pressure receiving chamber, so that a pressure control valve allows a large amount of hydraulic fluid to flow in a clutch or brake cylinder. At this time, potential detected by a pressure switch becomes zero level. Next, at the time point t , a filling command small current is supplied to the proportional solenoid, thereby decreasing the amount of hydraulic fluid, which flows from an input port to an output port. This state is maintained from the time point t to a time point t . At the termination of filling, peak pressure will not be generated, and a speed-changing shock in a clutch will not be generated, so that smooth switching can be accomplished.