Valve system in an injection molding system

Patent metadata

Field	Value
Publication number	US-10359124-B2
Application number	US-201715788099-A
Country	US
Kind code	B2
Filing date	Oct 19, 2017
Priority date	Nov 21, 2014
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

An injection molding apparatus including:
a valve pin driven by an actuator, the valve pin extending axially through at least a portion of the channel length of the fluid flow channel, the fluid flow channel including a throat, downstream flow of the injection fluid being restricted by a bulb portion of the pin, the valve pin having an intermediate position where downstream flow of injection fluid is unrestricted and a fully downstream position where downstream flow of injection fluid is stopped at both the gate and at the throat, wherein the actuator is driven by a valve assembly comprised of a spool mechanically driven by first and second actuators or solenoids that each separately engage the spool at opposing axial ends to effect movement of the spool back and forth between the drive fluid flow positions.

First claim

What is claimed is:

1. An injection molding apparatus comprising an injection molding machine, a manifold that receives injection fluid from the machine and routes the injection fluid during the course of an injection cycle from an upstream end toward a downstream end of a fluid flow channel disposed in the manifold or a nozzle communicating with the manifold, the fluid flow channel having a flow axis and a channel length, the fluid flow channel communicating at the downstream end with a gate to a cavity of a mold, the apparatus including:
a valve pin driven by an actuator, the valve pin extending axially through at least a portion of the channel length of the fluid flow channel, the valve pin having an upstream end interconnected to the actuator and a downstream end and a bulbous protrusion having an outer circumferential surface disposed between the upstream and downstream ends, the valve pin being drivable by the actuator axially upstream and downstream through the fluid flow channel,
the fluid flow channel including a throat having an inner circumferential surface having a selected throat configuration and throat diameter,
wherein the outer circumferential surface of the bulbous protrusion and the throat are adapted to enable a restricted flow of the injection fluid from an upstream side of the bulbous protrusion to a downstream side of the bulbous protrusion that reduces tensile forces on the pin when the bulbous protrusion is axially aligned with the throat,
the valve pin being drivable to a maximum downstream position where a distal tip end of the valve pin closes the gate and stops flow of the injection fluid through the gate,
wherein the fluid flow channel and the valve pin are configured or adapted such that the valve pin is movable axially upstream and downstream between an upstream position where the downstream flow of the injection fluid is restricted by the bulbous protrusion being axially aligned with the throat of the channel, an intermediate position where downstream flow of injection fluid is unrestricted and a fully downstream position where downstream flow of injection fluid is stopped at both the gate and at the throat.

2. The apparatus of claim 1 wherein:
the actuator is driven by a valve assembly comprised of a housing and a spool slidably mounted and controllably movable back and forth along an axis within the housing between two or more drive fluid flow positions,
the spool being mechanically driven by first and second actuators or solenoids that each separately engage the spool at opposing axial ends to effect movement of the spool back and forth between the drive fluid flow positions.

3. The apparatus of claim 2 wherein the actuators or solenoids are drivable in only one linear direction and adapted such that the first solenoid or actuator drives the spool in a first linear direction and the second solenoid or actuator drives the spool in a second linear direction opposite the first linear direction, the first and second solenoids or actuators being drivable at different times such that the spool is driven by only one or the other of the first and second solenoids or actuators at any one selected point in time.

4. The apparatus of claim 2 wherein the actuators or solenoids are controllably energizable to drive the spool a distance or length of travel or at a velocity of travel that is proportional to the degree or amount of voltage, current or power that is applied to the actuators or solenoids.

5. The apparatus of claim 1 wherein the bulbous portion has a diameter that is between about 0.01 and about 0.20 mm less than the throat diameter.

6. The apparatus of claim 1 wherein in the upstream position of the valve pin the bulbous portion is axially aligned with the throat, the valve pin including a reduced diameter neck portion that aligns with the throat when the pin is in the intermediate position to enable unrestricted flow of the injection fluid.

7. The apparatus of claim 1 wherein the valve pin includes an upstream portion configured or adapted to stop flow of injection fluid through the flow channel when the valve pin is in the fully downstream position.

8. The apparatus of claim 1 wherein the upstream position of the valve pin is a start position at a beginning of an injection cycle where the bulbous protrusion is axially aligned with the throat, the bulbous protrusion and the throat being adapted to enable a restricted flow of the injection fluid from an upstream side of the bulbous protrusion to a downstream side of the bulbous protrusion that reduces tensile forces on the pin.

9. The apparatus of claim 8 wherein the actuator is interconnected to a controller that includes a program that instructs the actuator to position the valve pin at the beginning of the injection cycle such that the bulbous protrusion is axially aligned with the throat.

10. The apparatus of claim 8 wherein the actuator is drivable at a rate of travel between zero and a maximum rate of travel, the actuator being interconnected to a controller that includes a program that instructs the actuator to drive the valve pin downstream from the start position to the maximum downstream position defining a stroke length, the program including instructions that instruct the actuator to drive the valve pin downstream at a rate of travel beginning from the start position along at least a portion of the stroke length that is less than the maximum rate of travel.

11. The apparatus of claim 1 wherein the bulbous portion and the throat are configured or adapted to enable a restricted flow of injection fluid that reduces a difference in pressure between fluid disposed upstream of the throat and fluid disposed downstream of the throat when the bulbous portion and the throat are axially aligned.

12. A method of forming a part by operation of the apparatus of claim 10 comprising injecting an injection fluid from the injection molding machine into the manifold and controlling flow of the injection fluid into the cavity by use of the controller such that the actuator is instructed to drive the valve pin downstream from the start position to the gate closed position at a rate of travel beginning from the start position along at least a portion of the stroke length that is less than the maximum rate of travel.

13. An injection molding apparatus comprising an injection molding machine, a manifold that receives injection fluid from the machine and routes the injection fluid during the course of an injection cycle from an upstream end toward a downstream end of a fluid flow channel disposed in the manifold or a nozzle communicating with the manifold, the fluid flow channel having a flow axis and a channel length, the fluid flow channel communicating at the downstream end with a gate to a cavity of a mold, the apparatus including:
a valve pin driven by an actuator, the valve pin extending axially through at least a portion of the channel length of the fluid flow channel, the valve pin having an upstream end interconnected to the actuator and a downstream end and a bulbous protrusion disposed between the upstream and downstream ends, the valve pin being drivable by the actuator axially upstream and downstream through the fluid flow channel,
the fluid flow channel including a throat having an inner circumferential surface having a selected throat configuration and throat diameter,
the fluid flow channel and the valve pin being configured or adapted such that the valve pin is movable axially upstream and downstream between an upstream position where the downstream flow of the injection fluid is restricted by the bulbous protrusion of the pin when the bulbous protrusion is axially alig

Assignees

• Synventive Molding Solutions Inc

Inventors

• Galati Vito
• Tan Zhuang Rui

Classifications

• F15B13/0442

  with proportional solenoid allowing stable intermediate positions · CPC title

• F15B2211/3111

  the pump port being closed in the centre position, e.g. so-called closed centre · CPC title

• B29C2945/76083

  Position · CPC title

• B29C2045/2886

  closing at a distance from the gate · CPC title

• F15B2211/3144

  the positions being continuously variable, e.g. as realised by proportional valves · CPC title