Hot Runner Actuator with Threaded Piston and Electric Motor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing actuators for hot runners in injection molding apparatuses face challenges such as contamination risks with hydraulic fluids, compressibility issues with pneumatic systems, and bulkiness in electric actuators, which affect the precision and efficiency of molding material flow control.
Innovation Solution
An actuator design featuring an electric motor with a fixed and rotating part, a piston, and a valve pin holder, allowing for both fluid pressure and electric mode operation to control the valve pin, enabling precise and forceful control of molding material flow through a threaded connection and anti-rotation mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic actuators are used to deliver high force for their size, then force output is improved, but contamination risk increases due to hydraulic fluid leaks
Solution Approach 1:
The actuator is divided into two independent systems: a hydraulic system for force generation and an electric system for precision control. The electric motor provides rotational motion that is converted to linear motion by a screw mechanism, while hydraulic pressure provides the force. This segmentation allows each system to perform its optimal function without the harmful effects of the other.
Solution Approach 2:
The patent combines hydraulic and electric actuation systems into a single integrated actuator. The electric motor drives a screw mechanism that moves a piston, while hydraulic pressure acts on the piston to provide force. This merging allows the actuator to achieve both high force and precise control, eliminating the contamination risk of purely hydraulic systems while maintaining the force advantage over purely electric systems.
2Object-affected harmful factors
If pneumatic actuators are used for clean operation, then contamination risk is reduced, but control precision deteriorates due to air compressibility
Solution Approach 1:
The actuator separates the functions of force generation and precision control into two independent systems. The hydraulic system provides force, while the electric motor with screw mechanism provides precise positional control. This segmentation eliminates the compressibility issue that plagues pneumatic systems by using an incompressible hydraulic fluid for force generation while maintaining electric control precision.
Solution Approach 2:
The screw mechanism acts as an intermediary between the electric motor and the hydraulic piston. It converts the rotational motion of the electric motor into linear motion that precisely controls the piston position, while the hydraulic fluid provides the force. This intermediary mechanism allows precise control without the compressibility problems of pneumatic systems.
3Object-affected harmful factors
If electric actuators are used for clean and accurate operation, then contamination risk and precision are improved, but device size increases due to bulkiness
Solution Approach 1:
The actuator segments the functions of force generation and precision control into separate systems. The electric motor provides precise rotational control, while the hydraulic system provides force. This allows the actuator to be more compact than a purely electric actuator of equivalent force output, since the hydraulic system can generate higher force in a smaller volume.
Solution Approach 2:
The patent uses hydraulic pressure to generate force, which allows for a more compact design compared to purely electric actuators. The hydraulic fluid transmits force efficiently, enabling smaller actuator dimensions while maintaining the clean operation and precision control benefits of electric actuation.
4Measurement precision
If a threaded connection is used between piston and valve pin holder, then positioning precision is improved, but device complexity increases due to anti-rotation mechanism
Solution Approach 1:
The actuator merges the positioning and force transmission functions into a single threaded connection. The screw mechanism provides both precise positioning through its lead geometry and force transmission through the threaded engagement. The anti-rotation feature is integrated into the valve pin holder design, combining multiple functions into unified components rather than separate elements.
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
This design provides a clean, precise, and forceful control of molding material flow, reducing contamination risks and bulkiness, while enabling accurate and efficient operation in both pressure and electric modes, suitable for various injection molding systems including co-injection and sequential injection.
Implementation Method 1
The rotating electric motor part is electromagnetically coupled to the fixed electric motor part and connected to the piston
Implementation Method 2
The piston is slidable along the axis in response to fluid pressure applied to the fluid chamber
Implementation Method 3
The valve pin holder is threadably connected to the piston for connecting to a valve pin. The threaded connection of the piston and the valve pin holder is aligned with the axis
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
An actuator for a hot runner has a piston (206) and a valve pin holder (214) threadably connected to the piston. The piston can be translated by fluid pressure and rotated by an electric motor (211). The valve pin holder is rotationally fixed, and therefore moves along the thread (207) when the piston is rotated. A valve pin (130) connected to the valve pin holder moves in response to fluid pressure and also in response to the electric motor rotating the piston.