초록 ▼

An energy efficient general purpose injection molding employs a hydraulic drive for injection and clamp machine functions and an electric drive for screw recovery. Both drives use AC "squirrel cage" induction motors under vector control. Speed command signals for the vector controls are generated by

An energy efficient general purpose injection molding employs a hydraulic drive for injection and clamp machine functions and an electric drive for screw recovery. Both drives use AC "squirrel cage" induction motors under vector control. Speed command signals for the vector controls are generated by the machine's controller utilizing state transition and predictive signal techniques to account for motor and motor/pump response latencies. Hydraulic drive efficiency is improved by varying motor speed/pump output to match cycle requirements to retain hydraulic drive advantages for mold clamp and injection functions while improving the electric drive performance for screw recovery.

대표청구항 ▼

[ What is claimed is:] [1.] An energy conserving hybrid injection molding machine comprising:an injection unit for injecting molding material into the mold cavity of a mold, said injection unit including a screw member rotatably and translatably carried in a tubular barrel, said barrel having an end

[ What is claimed is:] [1.] An energy conserving hybrid injection molding machine comprising:an injection unit for injecting molding material into the mold cavity of a mold, said injection unit including a screw member rotatably and translatably carried in a tubular barrel, said barrel having an end in fluid communication with said mold cavity;a first drive unit coupled to said injection unit for rotating said screw in said barrel; said first drive unit including a first AC induction motor, a mechanical coupling connecting said first AC induction motor with said screw and a vector control drive for controlling the operation of said first AC motor pursuant to a variable rotate command signal;a second drive unit coupled to said injection unit for translating said screw in said barrel; said second drive unit including a second AC induction motor, a hydraulic constant delivery pump driven by said second AC induction motor, a first hydraulic coupling between said pump and said screw for translatably moving said screw within said barrel and a second vector control drive for variably controlling the speed of said second AC induction motor pursuant to a variable injection command signal;a machine controller for generating said command signals to cause said molding machine to perform a given molding cycle, said machine controller including motor speed sensors measuring the speed of said first and second AC motors; and,said vector control drive for each motor including means for calculating maximum torque and flux current components passing through stator windings only from a speed signal comparing a motor speed signal with a set command speed signal whereby the torque produced by the AC motors is not used to control the motors.