Hydraulic systems for construction machinery

Abstract

The present invention discloses a hydraulic system which controls the opening degree 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. A hydraulic system for a construction machine according to the present invention is characterized by comprising: a hydraulic pump; a control valve controlling a discharge flow rate of the hydraulic pump; an arm cylinder and a swing motor each connected to the hydraulic pump; an arm control device and a swing control device; Pressure detection device for hydraulic pump; control amount detection device for stick control device; control amount detection device for swing control device; control stick control valve driven by stick cylinder; control swing control driven by swing motor valve; an arm regeneration valve that controls pressure at a return path upstream of the arm control valve when the arm naturally descends; an electronic proportional control valve that outputs a signal voltage for switching the arm regeneration valve; and a controller that performs control to The secondary signal voltage is generated by outputting the electronic control signal to both the control valve and the electronic proportional control valve to correspond to the detection signal input from the pressure detection device and the control amount detection device.

Description

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

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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