Patent attributes
The present invention provides a valve nozzle that can restrain property changes of an injecting melted resin by more strictly controlling the temperature of the injecting melted resin, wherein in the internal space or the rear space of a valve nozzle main body, a gate opening and closing mechanism is disposed which includes a torpedo provided with a coolant channel, a piston including a head portion, a shaft portion that is continued from the head portion and disposed in the internal space of the torpedo by being provided with a gap to serve as a resin flow channel on its outer circumferential surface, a tapered surface that is connected to the rear end of the shaft portion and serves as a surface for receiving the pressure of a resin in the resin flow channel, and a coil spring that presses the rear end part of the piston toward a gate, and when the pressure of the melted resin is at a predetermined value or less, the piston is pressed by the coil spring toward the gate to close the resin flow channel, and when the pressure of the resin reaches a predetermined value or more, it overcomes the pressing force of the coil spring and the head portion of the piston withdraws from the gate of the nozzle head to release the gate.
