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:
Oct. 16, 2018
Filed:
Jun. 10, 2015
Hitachi Construction Machinery Tierra Co., Ltd., Koka-shi, Shiga, JP;
Kiwamu Takahashi, Moriyama, JP;
Kazushige Mori, Moriyama, JP;
Masamichi Ito, Koka, JP;
Yoshifumi Takebayashi, Koka, JP;
Natsuki Nakamura, Koka, JP;
Yasuharu Okazaki, Namerikawa, JP;
Kenji Yamada, Toyama, JP;
Hitachi Construction Machinery Tierra Co., Ltd., Koka-shi, JP;
Abstract
In a hydraulic driving system for construction machines, when track motorsandare operated and the delivery pressure of a main pumpincreases to a second value PSof the set pressure of a main relief valve, the set pressure of a signal pressure relief valveincreases from a third value PAto a fourth value PA, which is smaller than the second value PSof the set pressure of the main relief valve, the difference between the second value PSand the fourth value PAbeing smaller than the target LS differential pressure. With such a structure, even if one of actuators reaches the stroke end and the delivery pressure of the hydraulic pump rises to the set pressure of the main relief valve, the other actuators do not stop, and further when the main relief valve is configured to increase the set pressure during operation of a specific actuator, the load pressure of the specific actuator does not increase to the increased set pressure of the main relief valve.