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 the 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.
3 Assignments
0 Petitions
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
9 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 the 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. - View Dependent Claims (2, 3, 4, 5, 7, 8, 9)
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6. 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 the 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 the 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