Hydraulic valve control device for heavy construction equipment
AssigneeVolvo Construction Equipment Holding Sweden AB
InventorJin Wook Kim
Life of this patent
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Abstract
An actuator is prevented from an abrupt descent by supplying a high-pressure hydraulic fluid drained upon the descent of the actuator to a path on a supply side of the actuator, provided is a main spool mounted in a path between a hydraulic pump and the actuator and controlling the drive of the actuator, a poppet mounted in a path between the main spool and the actuator and preventing the actuator from the descent, a spool mounted between a back-pressure and a feedback path of the poppet and communicating the back-pressure chamber with a path at an outlet of the main spool upon switching, and a fluid flow-reducing path communicating the back-pressure with the feedback path upon the switching of the spool and reducing hydraulic fluid drained from the actuator.
Claims3
A hydraulic valve control device for heavy construction equipment, comprising:
- a hydraulic pump;
- an actuator connected to the hydraulic pump and driven upon hydraulic fluid supplies;
- a main spool mounted in a path between the hydraulic pump and the actuator and switched upon a pilot signal pressure to control start, stop, and direction switching of the actuator;
- a poppet mounted to be opened and closed at a path between the main spool and the actuator and preventing the actuator from being descended;
- a spool mounted between a back-pressure chamber and a feedback path of the poppet and switched upon an application of the pilot signal pressure to communicate the back-pressure chamber with a path on an outlet of the main spool;
- said spool having a minute through hole orifice defining
- a fluid flow-reducing path connecting the back-pressure chamber and the spool and communicating the back-pressure chamber with the feedback path upon the switching of the spool to reduce hydraulic fluid drained from the actuator.
Dependencies are inferred from the claim text.