BR-112022006522-B1 - INJECTION MOLDING APPARATUS

Abstract

HOT ROUND ASSEMBLY WITH INTERNALLY COOLED AXIALLY MOUNTED ELECTRIC ACTUATOR. A hot round injection molding apparatus that facilitates the use of electric actuators in a compact design includes a hot round tubing that defines resin channels to transport resin to nozzles that serve as conduits to introduce liquid resin into a mold cavity, a valve pin configured for linear motion along a longitudinal geometric axis of the nozzle to control the flow of liquid resin through the nozzle, and an electric actuator having a body containing an electric motor, wherein the body of the electric actuator includes channels to circulate a coolant.

Inventors

• Scott Greb
• Anton Joerg
• Christian Striegel

Assignees

• INCOE CORPORATION

Dates

Publication Date

20260310

Application Date

20200930

Priority Date

20191011

Claims (3)

1. 1. Injection molding apparatus comprising: a pipe (26) defining a resin channel (24) for transporting liquid resin from an injection molding machine towards a mold cavity (12); a nozzle (34) for transporting liquid resin from the resin channel (24) to the mold cavity (12); a valve pin (36) configured for linear motion along a longitudinal geometric axis of the nozzle (34) to control the flow of liquid resin through the nozzle (34); an electric actuator (100) having a body containing an electric motor (101) and a linear drive shaft (102) with a bore (104), wherein both the electric motor (101) and the linear drive shaft (102) are contained in the body of the electric actuator (100), and wherein the valve pin (36) is directly or indirectly coupled to the drive shaft (102) within the bore (104), such that the linear motion the drive shaft (102) produces collinear motion of the valve pin (36); wherein the hole (104) extending through the drive shaft (102) is internally threaded and the valve pin (36) is directly or indirectly coupled to the drive shaft (102) via an externally threaded valve pin nut (106) threaded engagement of the internally threaded hole (104); wherein the valve pin nut (106) has a tool head engagement structure (114) for manual positioning of the valve pin (36) and valve pin nut (106) with respect to the drive shaft (102); characterized by the fact that it further comprises an externally threaded locknut (108) threaded into the internally threaded hole (104) and disposed adjacent to one side of the valve pin nut (106) opposite the valve pin (36).
2. 2. Apparatus, according to claim 1, characterized in that the locknut (108) has a tool head engagement structure (116) for manually tightening the locknut (108) against the valve pin nut (106).
3. 3. Apparatus, according to claim 1, characterized in that the electric actuator (100) is mounted on a support (126) fixed to the pipe (26), and further comprises an anti-rotation plate (130) disposed between a bottom of the support (126) and the electric actuator (100) and fixed in a releasable manner to the bottom of the support (126), the anti-rotation plate (130) having an opening (134) for the passage of the valve pin (36), the opening (134) having a shape configured to engage a section (136) of the valve pin (36) having a non-circular profile to prevent rotation of the pin (36) around the longitudinal geometric axis of the nozzle (34).

Description

Cross-reference to related requests [0001] This application claims priority over U.S. Application No. 16/599,564, filed on October 11, 2019, which is incorporated herein by reference in its entirety. FIELD OF REVELATION [0002] This disclosure relates to a hot chamber injection molding apparatus having an electric actuator configured to circulate a coolant fluid within the actuator body to facilitate mounting the actuator in close proximity to the hot chamber tubing while preventing overheating of the actuator's electric motor, and more particularly to such an apparatus in which the actuator can be axially mounted on the hot chamber tubing without substantial lateral clearance, allowing a plurality of actuators to be mounted on the tubing in very close proximity to each other. DISCUSSION OF THE PREVIOUS TECHNIQUE [0003] U.S. Patents Nos. 9,492,960 and 9,937,648 disclose an apparatus for controlling fluid flow to a mold, comprising a pipe, a valve pin having a geometric pin shaft, a pin connector and a rod, the valve pin being actuatable into and out of open and closed positions relative to the port. An electric actuator comprising an electric motor comprising a motor housing housing a drive shaft having a drive gear and a geometric drive shaft, a transmission comprising a gear shaft, the drive gear and the drive gear being interconnected in a driven manner and arranged so that the geometric drive shaft and the gear shaft are mounted non-coaxially or arranged relative to each other, wherein either of the motor housing or the transmission housing is removablely fixed to a mounting or top fixing plate that is mounted upstream of the pipe and fixedly interconnected to a mold. [0004] US Patent No. 6,294,122 discloses an injection molding machine including an apparatus for controlling the movement of a pin comprising a plastic melt flow channel having an outlet end for supplying molten plastic injected into the channel under pressure into a mold cavity, wherein the pin comprises an elongated rod having a shaft and an end, the pin being mounted in a sliding manner within the channel for movement along its geometric axis within the channel, an electrically driven motor driveable interconnected to a drive mechanism, wherein the drive mechanism is driveable interconnected to the end of the pin, the motor being controllably driveable to drive the pin through movement along its geometric axis within the channel. [0005] EP 2679374A1 discloses an apparatus for injection molding of plastic materials, which includes a hot chamber, at least one injector, including a movable nozzle within which is a valve pin driven by a rotary electric motor and an associated transmission including a screw and nut assembly for converting the rotation of the electric motor shaft into a translation of the valve pin. At least two of the valve pin, the rotary electric motor and the screw and nut assembly are set parallel to each other. BACKGROUND TO THE REVELATION [0006] In a hot chamber injection molding apparatus, the liquid resin (molten plastic) is kept in a molten state within channels defined in a heated pipeline. The channels transport the molten plastic material from an injection molding machine to one or more nozzles that carry the molten plastic to at least one mold cavity through ports defined at an interface between the nozzle and the mold cavity. After filling the mold cavity, only the mold cavity is cooled to allow the removal of a solid molded part. The resin in the pipeline and nozzle channels is maintained at a sufficient temperature to keep the plastic in a liquid state, thus reducing cycle time and waste compared to cold chamber injection molding apparatus, where the channels carrying resin are defined within the mold plates. [0007] Due to the susceptibility of electric actuators to degradation and failure when exposed to the high temperatures required in hot runner piping, hydraulic or pneumatic actuators are typically employed in hot runner injection molding equipment to control the flow of molten resin into the mold cavity (or cavities). In these hot runner injection molding equipment employing electric actuators, the electric actuators are positioned remotely from the piping and/or are provided with external cooling means (e.g., a cooled plate between the piping and the actuator), adding considerable complexity and expense compared to the more conventionally used pneumatic or hydraulic actuators. [0008] Despite these generally recognized disadvantages of electric actuators, they also have advantages, including the ability to more precisely control valve pin movement and positioning, which in turn can have associated advantages relevant to part quality and production efficiency. SUMMARY OF THE INVENTION [0009] This disclosure addresses the need to use electric actuators to control the position and movement of the valve pin in a hot runner injection molding apparatus, while protecting the actuator from overheating and provid