A hot runner-type injection structure 4 is provided with: a hot runner nozzle 5; and a valve pin 6 that is provided to be able to advance and retreat in the axial line O1 direction inside the flow passage of the hot runner nozzle 5 and that opens/closes the flow passage by coming into contact/being spaced apart from a valve opening/closing part 13 which has a tip part disposed on the tip side of the hot runner nozzle 5, wherein a heat insulating groove 16, which is recessed inward toward the axial line O1 side from an outer circumferential surface and extends in the circumferential direction, is provided on the outer periphery in a valve pin contact section M in which the valve opening/closing part 13 of the hot runner nozzle 5 is formed.

A hot runner-type injection structure 4 is provided with: a hot runner nozzle 5; and a valve pin 6 that is provided to be able to advance and retreat in the axial line O1 direction inside the flow passage of the hot runner nozzle 5 and that opens/closes the flow passage by coming into contact/being spaced apart from a valve opening/closing part 13 which has a tip part disposed on the tip side of the hot runner nozzle 5, wherein a heat insulating groove 16, which is recessed inward toward the axial line O1 side from an outer circumferential surface and extends in the circumferential direction, is provided on the outer periphery in a valve pin contact section M in which the valve opening/closing part 13 of the hot runner nozzle 5 is formed.

Injection molding apparatus (1) comprising: an actuator (14, 940, 941, 942) comprising a rotor (940r, 941r, 942r) controllably rotatable by electric power, the actuator (14, 940, 941, 942) being interconnected to a controller (16) that generates drive signals (DC), an electrical drive device (940d, 941d, 942d) comprising an interface that receives the drive signals (DC) and controllably distributes electrical energy or power in controllably varied amounts according to the drive signals (DC) to a driver (940dr, 941dr, 942dr) that drives the rotor (940r, 941r, 942r), a valve pin (1040, 1041, 1042) having an axis (X) and a control surface (43, 45, 102m) drivable upstream and downstream through a downstream feed channel (17, 19, 160, 940c, 941c, 942c) the downstream feed channel having a complementary surface (47, 103s) adapted to interface with the control surface (43, 45, 102m) upstream and away from the gate.

Injection molding apparatus (1) comprising: an actuator (14, 940, 941, 942) comprising a rotor (940r, 941r, 942r) controllably rotatable by electric power, the actuator (14, 940, 941, 942) being interconnected to a controller (16) that generates drive signals (DC), an electrical drive device (940d, 941d, 942d) comprising an interface that receives the drive signals (DC) and controllably distributes electrical energy or power in controllably varied amounts according to the drive signals (DC) to a driver (940dr, 941dr, 942dr) that drives the rotor (940r, 941r, 942r), a valve pin (1040, 1041, 1042) having an axis (X) and a control surface (43, 45, 102m) drivable upstream and downstream through a downstream feed channel (17, 19, 160, 940c, 941c, 942c) the downstream feed channel having a complementary surface (47, 103s) adapted to interface with the control surface (43, 45, 102m) upstream and away from the gate.

A screw driving device includes: a plasticization motor; a rotation drive shaft provided coaxially with a screw and configured to rotate the screw; and a transmission mechanism configured to decelerate rotation of the plasticization motor and transmit the rotation to the rotation drive shaft. The transmission mechanism includes: a speed reducer whose output shaft is coupled to the rotation drive shaft; a drive rotation member provided in the plasticization motor; a driven rotation member provided on an input shaft of the speed reducer; and one endless string-shaped force transmission member wound around the drive rotation member and the driven rotation member.

A screw driving device includes: a plasticization motor; a rotation drive shaft provided coaxially with a screw and configured to rotate the screw; and a transmission mechanism configured to decelerate rotation of the plasticization motor and transmit the rotation to the rotation drive shaft. The transmission mechanism includes: a speed reducer whose output shaft is coupled to the rotation drive shaft; a drive rotation member provided in the plasticization motor; a driven rotation member provided on an input shaft of the speed reducer; and one endless string-shaped force transmission member wound around the drive rotation member and the driven rotation member.

An injection molding apparatus and method of fabricating a molded part are provided. The apparatus may include a barrel, a nozzle enclosing an end of the barrel and defining an opening in fluid communication with an inside of the barrel, and an extrusion screw positioned at least partially inside the barrel and rotatable relative to the barrel. The extrusion screw may include a screw tip. Relative axial movement between the barrel and the extrusion screw may open or close the opening of the nozzle to permit or prevent, respectively, material flow through the opening of the nozzle. The method may include clamping a mold, opening a nozzle, rotating the extrusion screw to pump a molten material into the mold until the mold is filled, closing the nozzle, and unclamping the mold to release a molded part.

An injection molding apparatus and method of fabricating a molded part are provided. The apparatus may include a barrel, a nozzle enclosing an end of the barrel and defining an opening in fluid communication with an inside of the barrel, and an extrusion screw positioned at least partially inside the barrel and rotatable relative to the barrel. The extrusion screw may include a screw tip. Relative axial movement between the barrel and the extrusion screw may open or close the opening of the nozzle to permit or prevent, respectively, material flow through the opening of the nozzle. The method may include clamping a mold, opening a nozzle, rotating the extrusion screw to pump a molten material into the mold until the mold is filled, closing the nozzle, and unclamping the mold to release a molded part.

A stepped flight is formed on a screw of an injection molding machine. The stepped flight is a flight in which a step-shaped step portion is formed on a top portion thereof. The top portion of the flight includes a large diameter portion on an upstream side and a land portion on a downstream side. When a gap ratio m of a gap H.sub.1 between the land portion and a bore of the heating cylinder to a gap H.sub.2 between the large diameter portion and the bore is defined as H.sub.1/H.sub.2, the gap ratio m is selected to be 2.3≤m≤6.4.

A stepped flight is formed on a screw of an injection molding machine. The stepped flight is a flight in which a step-shaped step portion is formed on a top portion thereof. The top portion of the flight includes a large diameter portion on an upstream side and a land portion on a downstream side. When a gap ratio m of a gap H.sub.1 between the land portion and a bore of the heating cylinder to a gap H.sub.2 between the large diameter portion and the bore is defined as H.sub.1/H.sub.2, the gap ratio m is selected to be 2.3≤m≤6.4.