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:
Aug. 19, 2025
Filed:
Aug. 31, 2022
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Ryohei Fukuchi, Tsukuba, JP;
Shota Ishida, Tsukuba, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A construction machine including a solenoid valve that reduces a boom lowering pilot pressure for a second directional control valve and a controller that controls the solenoid valve is provided. The controller computes a first opening degree command value in such a manner that a communication area between a boom lowering pressure reducing valve and a pressure receiving chamber of the second directional control valve decreases in association with a bottom pressure of a boom cylinder, computes a second opening degree command value in such a manner that the communication area increases in association with increase in a boom lowering operation amount, decides a minimum opening degree command value as an opening degree command value of the solenoid valve when an elapsed time after boom raising operation is shorter than a set time and decides a minimum selected value of the first and second opening degree command values as the opening degree command value of the solenoid valve when the elapsed time is equal to or longer than the set time, and outputs a command signal according to the decided opening degree command value to the solenoid valve.