LOAD HANDLING REGENERATION METHOD AND LOAD HANDLING REGENERATION SYSTEM OF BATTERY TYPE INDUSTRIAL VEHICLE

摘要

An energy recovering system in a hydraulic lift device of a battery operated industrial truck. With the system, working oil can be supplied to other hydraulic actuators while energy recovering operation is performed by the hydraulic lift device, occurrence of pressure pulsation in the working oil can be prevented, and energy recovering efficiency is increased. The hydraulic lift device comprises a lift cylinder(1) for lifting a fork F, an electric motor (4) rotated by power supply from a battery (5), a hydraulic pump(3) for supplying pressurized oil to the lift cylinder(1), a control valve(14) disposed in a pressurized oil supply path(23), and a controller(17). The controller(17) controls the opening of the control valve (14) and rotation speed of the electric motor(4) which functions as an electric generator driven by the hydraulic pump(3) rotated by the action of the pressurized oil returning from the lift cylinder (1) when a load is lowered so that the generated electricity charges the battery(5) to recover the potential energy of the load.