Patent ID: 9079755
Filing Date: 2015-07-14
Classification: B60L,B66F

Abstract:
1. An energy reclaiming system for an electric forklift truck, including an electronic device operated by a motor when a working machine is raised and operated by a generator when the working machine is lowered, a hydraulic pump/motor connected to the electronic device and configured to perform two functions of a hydraulic pump and a hydraulic motor, a main control valve unit including a lift cylinder operating unit connected to the hydraulic pump/motor and configured to operate a lift cylinder and a secondary consumer operating unit connected to the hydraulic pump/motor and configured to operate a secondary consumer, and a control lever including a control valve configured to control the lift cylinder or the secondary consumer through the lift cylinder operating unit and the secondary consumer operating unit of the main control valve unit, respectively, the energy reclaiming system comprising: a working fluid return line provided with a flow amount limiting valve configured to interrupt a flow of a return flow amount generated by the lift cylinder when the working machine is lowered; and an energy reclaiming unit installed in the working fluid return line and configured to, if the return flow amount generated when the working machine is lowered is smaller than a flow amount consumed by the secondary consumer, reclaim the return flow amount to an oil tank, and, if the return flow amount generated when the working machine is lowered is larger than the flow amount consumed by the secondary consumer, guide the return flow amount to the hydraulic pump/motor; wherein the energy reclaiming unit includes a hydraulically controlled two position valve installed in the working fluid return line and having a first position for, if a return pilot pressure when the working machine is lowered is smaller than a supply pilot pressure during an operation of the secondary consumer, opening a passage of the working fluid generated by the lift cylinder to the oil tank, and a second position for, if the return pilot pressure when the working machine is lowered is larger than the supply pilot pressure during an operation of the secondary consumer, opening the passage of the working fluid generated by the lift cylinder to the hydraulic pump/motor.