Hydraulic system for construction machinery

Abstract

Disclosed is a hydraulic system for controlling the degree of openness of an arm regeneration valve by driving an electronic proportional control valve during a combined operation of simultaneously operating an arm and a swing device. The hydraulic system for construction machinery according to the present invention is characterized by comprising: a hydraulic pump; a control valve for controlling the discharge flow from the hydraulic pump; an arm cylinder and a swing motor, each connected to the hydraulic pump; an arm controlling device and a swing controlling device; a pressure detecting means for the hydraulic pump; a controlled amount detecting means for the arm controlling device; a controlled amount detecting means for the swing controlling device; an arm control valve for controlling the driving of the arm cylinder; a swing control valve for controlling the driving of the swing motor; an arm regeneration valve for controlling the pressure at an upstream return passage of the arm control valve when the arm naturally descends; an electronic proportional control valve for outputting a signal voltage for switching the arm regeneration valve; and a controller for performing a control so as to generate a secondary signal voltage by outputting electrical control signals to both the control valve and the electronic proportional control valve so as to correspond to detection signals inputted from the pressure detecting means and controlled amount detecting means.

Description

technical field [0001] The invention relates to a hydraulic system for a construction machine. More specifically, the present invention relates to a hydraulic system for a construction machine capable of controlling the opening degree of an arm regeneration valve through an electronic proportional control valve when a combined operation of simultaneously driving an arm and a swing device is performed. Background technique [0002] In general, the term regeneration refers to a process in which hydraulic fluid returned from the return side of a hydraulic actuator refills the flow path on the supply side to prevent cavitation due to lack of hydraulic fluid on the supply side and to ensure hydraulic Smooth operating speed of the actuator. [0003] Such as figure 1 The illustrated hydraulic system for a construction machine according to the prior art comprises: a variable displacement hydraulic pump (hereinafter referred to as "hydraulic pump") 1; [0004] Stick cylinder 2 and...

AI Technical Summary

Problems solved by technology

[0020] As described above, when the opening area of ​​the arm regeneration valve 11 is increased during the combined operation in which the arm and the swing are simultaneously driven, restriction such as cavitation occurs

For this reason, a pressure loss occurs, resulting in a decrease in efficiency

In addition, although the driving speed of the arm can be controlled by the arm regeneration valve 11, there is still a limitation in satisfying all the various operating conditions

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