Construction Machine
AssigneeHitachi Construction Machinery Co., Ltd.
InventorsHidekazu MORIKI, Akira KANAZAWA, Takaaki CHIBA, Shinya IMURA, Yasutaka TSURUGA
Life of this patent
Estimating the term…
Abstract
To provide a construction machine that can highly precisely control branch flows from a hydraulic pump to a plurality of hydraulic actuators without being affected by load conditions. A controller (100) has a meter-out valve control section (140) configured to calculate a target opening area of a second meter-out valve (65a) (65b) according to a pressure difference between a supply pressure and a second meter-in pressure, or calculate a target opening area of a first meter-out valve (55a) (55b) according to a pressure difference between the supply pressure and the first meter-in pressure.
Claims5
A construction machine comprising:
- a tank;
- a hydraulic pump;
- a first hydraulic actuator and a second hydraulic actuator each having two supply and discharge ports;
- a first meter-in valve provided on a hydraulic line connecting the first hydraulic actuator to the hydraulic pump;
- a second meter-in valve provided on a hydraulic line that establishes communication between the second hydraulic actuator and the hydraulic pump;
- a first meter-out valve provided on a hydraulic line that establishes communication between the first hydraulic actuator and the tank;
- a second meter-out valve provided on a hydraulic line that establishes communication between the second hydraulic actuator and the tank;
- a first pressure sensor that senses a first meter-in pressure that is a load pressure on the first hydraulic actuator;
- a second pressure sensor that senses a second meter-in pressure that is a load pressure on the second hydraulic actuator;
- a third pressure sensor that senses a supply pressure that is a delivery pressure of the hydraulic pump;
- and
- a controller having a meter-in valve control section configured to calculate a target opening area of the first meter-in valve according to a pressure difference between the supply pressure and the first meter-in pressure, and calculate a target opening area of the second meter-in valve according to a pressure difference between the supply pressure and the second meter-in pressure, wherein
- the controller has a meter-out valve control section configured to calculate a target opening area of the second meter-out valve according to the pressure difference between the supply pressure and the second meter-in pressure, or calculate a target opening area of the first meter-out valve according to the pressure difference between the supply pressure and the first meter-in pressure.
Dependencies are inferred from the claim text.