Stepper Motor Expansion Valve With Integrated Stop and Low Wear
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Solution Overview
Problem
Existing expansion valves are complex, prone to high wear, and expensive to manufacture, making them difficult to replace and maintain.
Innovation Solution
A compact expansion valve design utilizing a stepper motor, a hollow shaft, a center spool, and a spiral body with a sliding ring, which allows for axial movement and reduced wear through a threaded connection, and incorporates a sleeve element with a compression spring and force transmission element for torque decoupling, enabling easy replacement and pressure balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a complex stopper structure with multiple components (stopper, engagement element, annular support pin) is used to define end positions, then the expansion valve can achieve precise axial movement control, but the device complexity increases significantly
Solution Approach 1:
The patent combines the stopper, engagement element, and support pin into a single integrated stop element with an L-shaped design. The horizontal portion engages with the rotor while the vertical portion contacts the valve needle, eliminating the need for separate components and reducing overall structural complexity while maintaining precise axial movement control
Solution Approach 2:
The integrated stop element serves multiple functions simultaneously: it acts as a stopper to define end positions, an engagement element to connect with the rotor, and a support structure for the valve needle. This multi-functionality reduces the number of components needed while achieving the same precise control objective
2Reliability
If multiple separate components (rotor, spool, hollow shaft, spiral body) are used to transfer rotational movement to axial movement, then the expansion valve achieves reliable force transmission, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent integrates the hollow shaft and spiral body into a single component, eliminating the need for separate force transmission elements. The integrated design maintains reliable torque transmission from the rotor to the valve needle while reducing the number of parts that require assembly and maintenance
3Reliability
If a complex configuration with multiple components is used, then the expansion valve achieves reliable functionality, but the ease of replacement and maintenance deteriorates
Solution Approach 1:
The patent divides the expansion valve into two main replaceable segments: the motor assembly (stator and rotor) and the valve assembly (valve needle, seat, and integrated stop element). This segmentation allows the valve components to be replaced independently of the motor, significantly improving maintenance ease while maintaining reliable functionality
Solution Approach 2:
The valve needle and seat are designed as separate, extractable components from the housing, allowing them to be removed and replaced without disassembling the entire valve or motor assembly. This extraction capability simplifies maintenance operations while preserving the reliability of the overall system
4Reliability
If traditional expansion valve designs are used, then the valve achieves pressure reduction functionality, but wear increases due to complex moving parts and contact surfaces
Solution Approach 1:
The valve needle and seat are extracted as separate, easily replaceable components with simplified geometries that reduce contact stress and wear. The integrated stop element also has fewer contact surfaces compared to traditional multi-component designs, further reducing wear points and extending service life while maintaining pressure reduction functionality
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
The design results in a compact, low-wear expansion valve with simplified replacement and maintenance, reduced complexity, and cost-effective production, while maintaining reliable functionality.
Implementation Method 1
Threading an inner thread in an outer thread transposes the rotation of the rotor into a linear movement
Implementation Method 2
a compression spring and a force transmission element
Data Source
AI summary
An expansion valve operable by a stepper motor, the expansion valve including a housing; a hollow shaft arranged in the housing; a valve base that supports the hollow shaft and closes the housing; a rotor that is drivable by a stator of the stepper motor; a center spool arranged within the hollow shaft and drivable by the rotor so that a rotation of the center spool is transferrable by a threaded connection into an axial movement of the center spool that opens or closes the expansion valve; and a spiral body that includes a thread turn and that is arranged about an enveloping surface of the hollow shaft and that is drivable by the rotor, wherein a stop body is arranged at the hollow shaft and movable in the thread turn of the spiral body.