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:
Sep. 08, 2020
Filed:
Nov. 07, 2017
Hitachi Construction Machinery Co., Ltd., Taito-ku, Tokyo, JP;
Takamasa Kai, Tokyo, JP;
Hiromasa Takahashi, Tsuchiura, JP;
Teppei Saitoh, Tokyo, JP;
Juri Shimizu, Tsuchiura, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A construction machine includes a bidirectionally tiltable type hydraulic pump, a hydraulic cylinderhaving a cap chamberand a rod chamber, a first flow pathconnecting the hydraulic pumpand the cap chamber, a second flow pathconnecting the hydraulic pumpand the rod chamber, a discharge flow pathbranched from the first flow path, a discharge valvethat is disposed in the discharge flow pathand controls a discharge rate of hydraulic working oil from the cap chamberto the discharge flow path, an operation devicethat instructs an action of the hydraulic cylinder, and a controller. The controllercontrols the hydraulic pumpand the discharge valvesuch that at least a part of hydraulic working oil discharged from the cap chamberis discharged to the discharge flow pathwhen an operation amount of the operation devicelies within a fine operation region during a pulling action of the hydraulic cylinderin a state that a load is applied in a contraction direction. Accordingly, operability improves during fine operation of the pulling action of the hydraulic cylinder in the state that the load is applied in the contraction direction.