Injection Nozzle Shutter Stroke Control by Hydraulic Volume Metering
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Solution Overview
Problem
Current fluid-powered actuators in injection molding machines lack precise control over stroke adjustment, particularly for complex parts requiring precise positional control of shutters, which is typically achieved with expensive and complex electric actuators.
Innovation Solution
A method and system utilizing a hydraulic actuator with a movable piston and auxiliary tank to control the fluid volume, allowing precise displacement of the shutter by determining and adjusting the volume of fluid transferred between the actuator chamber and the auxiliary tank, enabling precise adjustment of stroke and intermediate positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electric actuators are used to control shutter position, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex electronic control systems with a hydraulic-mechanical system. A piston displaces a predetermined volume of fluid into or from the actuator chamber, creating a direct mechanical-linkage between fluid volume and shutter position. This eliminates the need for complex electronic command and control devices while maintaining precise stroke adjustment capability.
Solution Approach 2:
The patent changes the control parameter from electrical signals to fluid volume. By determining and displacing a predetermined volume of fluid, the system directly controls shutter position through hydraulic pressure and volume displacement, simplifying the control mechanism while preserving precision.
2Device complexity
If fluid-powered actuators are used to reduce cost, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The patent calculates and determines the predetermined volume of fluid required for the desired shutter stroke before actuation. This pre-determination of fluid volume ensures that when the fluid is displaced into or from the chamber, the shutter achieves the exact required position, maintaining precision without complex control systems.
Solution Approach 2:
The patent introduces a piston as an intermediary mechanism that converts fluid volume displacement into linear shutter movement. The piston's displacement of a predetermined fluid volume creates a direct, proportional relationship between fluid volume and shutter position, enabling precise control through simple hydraulic actuation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables cost-effective and precise control of the shutter's stroke and speed in injection molding machines, improving the quality of complex parts by allowing for precise positional control and efficient fluid management without the need for complex electronic control systems.
Implementation Method 1
a piston which is movably mounted in the chamber, displaced linearly thanks to the thrust of the fluid
Implementation Method 2
The predetermined amount of fluid is measured and determined before injecting it into the chamber. By means of the calculation of the amount of fluid injected in the chamber, e.g. through a flow-meter
Data Source
Figure 1
Figure 2~3
AI summary
A method is described for operating an actuator (10) adapted for moving by means of a pressurized fluid the shutter (12) of an injection nozzle for molten material into a mould, wherein the shutter (12) moves from a closing position, in which there is no passage of molten material through the nozzle, to an opening position, in which there is passage of molten material through the nozzle, and the shutter (12) comprises a chamber (18), and a piston (14) which is movably mounted in the chamber (18), displaced linearly thanks to the thrust of the fluid and connected to the shutter (12) to move it. The shutter (12) is moved by inserting or removing the predetermined amount of fluid into/from the chamber (18).