Stepper Expansion Valve Travel Stop Using a Single Coil Spring
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Solution Overview
Problem
Conventional stepper motor expansion valves require intricate and costly intertwined springs for safety stalls or hard stops, leading to increased component count, assembly time, and complexity.
Innovation Solution
A single coil spring or wave washer is used as a travel limit member, movable along the shaft's threads to provide safety stalls or hard stops for fully open and closed positions, eliminating the need for intricate springs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intricate intertwined springs are used for safety stalls, then the valve can achieve hard stops for fully open and closed positions, but the component count, assembly time, and complexity increase
Solution Approach 1:
The patent combines multiple spring functions into a single spring component. The one-coil spring performs both the safety stall function and the hard stop function for both fully open and fully closed positions, eliminating the need for separate intertwined springs. This merging reduces component count while maintaining the reliability of the safety stall mechanism.
Solution Approach 2:
The single one-coil spring is designed to perform multiple functions: it provides the safety stall function, creates hard stops for both fully open and fully closed positions, and guides the valve member's movement. This multi-functional design eliminates the need for separate components for each function, reducing overall device complexity.
2Reliability
If intricate intertwined springs are used for safety stalls, then the valve can achieve hard stops for fully open and closed positions, but the assembly time increases
Solution Approach 1:
By merging multiple spring components into a single one-coil spring, the assembly process is simplified. Instead of installing and positioning multiple intertwined springs, the assembler only needs to install one spring component, significantly reducing assembly time while maintaining the hard stop function.
Solution Approach 2:
The patent extracts and eliminates the unnecessary complexity of multiple intertwined springs, keeping only the essential one-coil spring that provides the required hard stop function. This extraction removes redundant components that would otherwise increase assembly time.
3Device complexity
If a single coil spring is used as travel limit member, then component complexity is reduced, but precise control of refrigerant flow must be maintained
Solution Approach 1:
The one-coil spring is integrated with the valve member and shaft to provide continuous mechanical feedback during operation. As the valve member moves, the spring's compression and extension provide tactile and mechanical feedback that ensures precise positioning and maintains control precision, compensating for the reduced component complexity.
Solution Approach 2:
The spring is designed to be dynamic and responsive to the valve member's movement. It provides variable resistance and force throughout its range of motion, allowing for precise control adjustments while maintaining simplicity. The dynamic characteristics of the spring ensure that refrigerant flow control precision is maintained despite the simplified configuration.
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 solution reduces component complexity, simplifies assembly, and lowers costs while maintaining precise control of refrigerant flow, enhancing the operational efficiency and reliability of the valve.
Implementation Method 1
A single coil spring or wave washer is used as a travel limit member, movable along the shaft's threads to provide safety stalls or hard stops for fully open and closed positions
Data Source
AI summary
A valve includes a shaft having threads along at least a portion of a length of the shaft. A travel limit member (e.g., a coil spring, a washer, etc.) is disposed within one or more of the threads. The travel limit member may comprise a coil spring configured to be movable within the threads along the shaft when the shaft is rotated relative to the coil spring. The coil spring is configured to be operable for providing: a safety stall or hard stop for a fully open position of the valve when the coil spring is within the top thread and/or runs out of the threads after having traveled upwardly along the shaft within the threads; and a safety stall or hard stop for a fully closed position of the valve when the coil spring contacts a stop after having traveled downwardly along the shaft within the threads.