Hydraulic excavator
AssigneeKomatsu Ltd.
InventorTakeshi Takaura
Life of this patent
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Abstract
There is provided a hydraulic excavator in which invasion of a design surface by a work implement can be suppressed. A boom-lowering proportional solenoid valve is provided in a boom-lowering pilot conduit connected to a boom-lowering pilot port. A first pressure sensor detects a pressure generated in the boom-lowering pilot conduit between a control lever and the boom-lowering proportional solenoid valve. A controller controls an opening degree of the boom-lowering proportional solenoid valve based on the pressure detected by the first pressure sensor. The controller gently increases, from zero, a current value outputted to the boom-lowering proportional solenoid valve.
Claims8
A hydraulic excavator, comprising:
- a boom;
- a pilot switching valve for said boom having a boom-lowering pilot port and controlling operation of said boom;
- a boom-lowering pilot conduit connected to said boom-lowering pilot port;
- a boom-lowering proportional solenoid valve provided in said boom-lowering pilot conduit;
- a control lever operated by an operator;
- a first pressure sensor detecting a pressure generated in said boom-lowering pilot conduit between said control lever and said boom-lowering proportional solenoid valve;
- and
- a controller controlling an opening degree of said boom-lowering proportional solenoid valve based on the pressure detected by said first pressure sensor, wherein
- said controller gently increases, from zero, a current value outputted to said boom-lowering proportional solenoid valve.
Dependencies are inferred from the claim text.