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. 22, 2022
Filed:
May. 21, 2018
Kawasaki Jukogyo Kabushiki Kaisha, Kobe, JP;
Hideyasu Muraoka, Akashi, JP;
Tomomichi Nose, Akashi, JP;
Nobuyuki Kinoshita, Kakogawa, JP;
Takashi Okashiro, Kakogawa, JP;
Moriyuki Sakamoto, Kobe, JP;
KAWASAKI JUKOGYO KABUSHIKI KAISHA, Kobe, JP;
Abstract
A hydraulic drive system of construction machine including: turning motor; turning operation device that outputs turning operation signal corresponding to inclination angle of operating lever; turning direction switching valve including spool and driver, driver receiving command current and driving spool, turning direction switching valve increasing amount of hydraulic liquid supplied to turning motor and amount of hydraulic liquid discharged from turning motor with increase in command current; controller that feeds command current to turning direction switching valve, wherein command current increases in accordance with increase in turning operation signal; and pressure sensor that detects outflow pressure of turning motor. Where turning operation signal decreases, when outflow pressure of turning motor, which is detected by pressure sensor, is higher than threshold and is increasing, controller feeds command current to turning direction switching valve, wherein a moving speed of spool is kept to be less than or equal to limiting value.