We have developed a novel energy-saving hydraulic pump system Super Unit that comprises a high-efficiency motor, low-inertia pump and an inverter controller (We call this type of system ‘hybrid’). Compared with conventional hydraulic pumps each driven by a constant speed induction motor, our novel hydraulic pump system driven by a high-efficiency variable-speed IPMSM (Interior Permanent Magnet Synchronous Motor) features energy-saving of 40% or more when used for an injection molding machine which is a typical application of this new pump system.
By means of a pressure feedback control function and run speed control software on the controller, the pressure and fl ow rate of the hydraulic fluid are accurately controlled according to a command from the controller of the molding machine. This control software allows a high-torque high-precision motor to drive a low-inertia pump: as a result, high-speed high-response control of hydraulic actuators is realized, thereby the quality of molding products obtainable from injection machines controlled by our system is higher compared with quality resulting from conventional systems. A series of our variable-speed pump system products adopting hybrid hydraulic pressure technology are available for NC lathes, machining centers and other industrial machines such as a press machine.