Patent ID: 8869924
Filing Date: 2014-10-28
Classification: E02F,F15B

Abstract:
1. A hybrid excavator including a device that brings an electro-hydraulic actuator mounted thereon to a quick stop, comprising: an RCV configured to output a manipulation signal based on a manipulation amount so as to manipulate an work apparatus a first detection sensor configured to detect the manipulation signal outputted from the RCV based on the manipulation amount and output a detection signal; an electric motor; a second detection sensor configured to detect the number of rotations of the electric motor and output a detection signal; a hydraulic pump-motor connected to the electric motor; a hydraulic cylinder connected to the hydraulic pump-motor and configured to be driven to expand and contract in response to supply of hydraulic fluid thereto; first and second hydraulic valves respectively installed in first and second flow paths between the hydraulic pump motor and the hydraulic cylinder; a third hydraulic valve installed in a connection path which is connected to first and second branched flow paths that are branch-connected to first and second flow paths on the upper stream sides of the first and second hydraulic valves and first and second flow paths on the lower stream sides of the first and second hydraulic valves, respectively, and configured to compensate for or bypass a flow rate to overcome a difference in flow rates that occurs when forward and reverse rotation of the hydraulic pump-motor is changed due to a difference in cross-sectional area between a large chamber and a small chamber of the hydraulic cylinder; and a control unit configured to receive the manipulation signal of the RCV from the first detection sensor and the number of rotations of the electric motor from the second detection sensor, compare the received manipulation signal and the number of rotations with data of pre-stored working conditions, and output a control signal for application to the first hydraulic valve or the second hydraulic valve to switch the first hydraulic valve or the second hydraulic valve so that the hydraulic fluid is blocked from being fed back to the hydraulic pump-motor from the hydraulic cylinder to cause the work apparatus to be brought to a quick stop.