Hybrid excavator boom actuating system and method for controlling same
First Claim
1. A boom actuating system for use with a hybrid excavator, comprising:
- an electric motor operated as a motor or a generator;
an electricity storage device configured to store electricity generated in the electric motor;
a hydraulic pump motor driven by the electric motor to supply hydraulic fluid to a boom;
a boom control valve configured to selectively connect or disconnect an outlet line and an inlet line of the hydraulic pump motor to or from a head or a rod of a boom cylinder operating the boom;
a motor bypass valve connected to the outlet line and the inlet line to interconnect the outlet line and the inlet line or disconnect the outlet line from the inlet line; and
a controller configured to control the electric motor, the hydraulic pump motor, the boom control valve, and the motor bypass valve;
wherein in a case where a flow rate discharged from the head of the boom after the descending of the boom is initiated is equal to or larger than a predetermined value, the controller operates the hydraulic pump motor, and switches the motor bypass valve so as to disconnect the outlet line and the inlet line.
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Accused Products
Abstract
The present disclosure relates to a hybrid excavator boom actuating system and to a method for controlling the same. The boom actuating system comprises: an electric motor serving as a motor or a generator; an ultra capacitor for storing electricity generated by the electric motor; a hydraulic pump motor driven by the electric motor to supply hydraulic fluid to a boom; a boom control valve which has a closed circuit for selectively connecting or disconnecting an outlet line and an inlet line of the hydraulic pump motor to or from a head or a rod side of the boom; a main pump driven by the engine to supply hydraulic fluid to a bucket, a travel motor or an arm; a motor bypass valve connected to the outlet line and the inlet line to interconnect the outlet line and the inlet line or disconnect the outlet line from the inlet line; and a controller for controlling the electric motor, the hydraulic pump motor, the boom control valve and the motor bypass valve.
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Citations
7 Claims
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1. A boom actuating system for use with a hybrid excavator, comprising:
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an electric motor operated as a motor or a generator; an electricity storage device configured to store electricity generated in the electric motor; a hydraulic pump motor driven by the electric motor to supply hydraulic fluid to a boom; a boom control valve configured to selectively connect or disconnect an outlet line and an inlet line of the hydraulic pump motor to or from a head or a rod of a boom cylinder operating the boom; a motor bypass valve connected to the outlet line and the inlet line to interconnect the outlet line and the inlet line or disconnect the outlet line from the inlet line; and a controller configured to control the electric motor, the hydraulic pump motor, the boom control valve, and the motor bypass valve; wherein in a case where a flow rate discharged from the head of the boom after the descending of the boom is initiated is equal to or larger than a predetermined value, the controller operates the hydraulic pump motor, and switches the motor bypass valve so as to disconnect the outlet line and the inlet line. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of controlling a boom actuating system for use with a hybrid excavator, comprising:
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detecting an amount of operation of a boom joystick; determining whether a boom descends according to the operation of the boom joystick; when descending of the boom is initiated, switching a motor bypass valve so as to interconnect an outlet line and an inlet line; determining whether the flow rate discharged from a head of the boom is equal to or larger than a predetermine value; and when the flow rate is equal to or larger than the predetermine value, operating a hydraulic pump motor, and switching the motor bypass valve so as to disconnect the outlet line and the inlet line.
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Specification