Patent ID: 6280170
Filing Date: 2001-08-28
Classification: B29C

Abstract:
A hydraulic control system for an injection molding machine, comprising:a plurality of hydraulic actuators assigned respectively for driving functional units included in the injection molding machine;a hydraulic circuit including solenoid valves for serving to direct the hydraulic fluid to the optional hydraulic actuators to drive the hydraulic actuators selectively;a controller that provides flow control signals for instructing flow rates corresponding to predetermined operating speeds at which the hydraulic actuators are driven according to respective stages of an injection molding cycle;a speed control valve, disposed in the hydraulic circuit at a position downstream of the hydraulic fluid to be supplied to the hydraulic actuators on the basis of the flow control signals;a motor controller using an inverter to control the pump driving motor for rotation at a desired rotational speed; anda pump speed setting means, connected between the controller and the motor controller, for determining a rotational speed instruction given to the motor controller on the basis of the flow control signals provided by the controller.