Electronic Expansion Valve Disc Spring to Prevent Sludge Buildup
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Solution Overview
Problem
Existing refrigerant flow rate control devices using electromagnetic valves suffer from sludge buildup due to sliding contact, leading to potential clogging and malfunction after numerous cycles, requiring axial direction guides and being costly.
Innovation Solution
An electronic expansion valve employing a disc spring with spiral slits as an elastic member, eliminating the need for axial direction guides and reducing sludge formation by increasing radial rigidity and optimizing axial direction driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coil spring is used as a return elastic member, then the valve body can be closed by elastic force, but radial force acts on the valve body causing sliding contact and sludge generation
Solution Approach 1:
The coil spring is divided into multiple independent spiral elastic members, each providing elastic force while reducing radial force components. The segmentation of the elastic function across multiple elements reduces the harmful radial forces that cause sliding contact and sludge generation.
Solution Approach 2:
The spiral elastic members are configured with asymmetric geometry where the spiral shape provides elastic recovery force in the axial direction while the geometry inherently minimizes radial force components. This asymmetric design allows the elastic member to provide closing force without generating the radial forces that cause sliding contact.
2Ease of operation
If axial direction guides are added to regulate valve body movement, then the valve body can be properly driven in the axial direction, but the device complexity increases
Solution Approach 1:
The axial direction guide structure is completely removed from the system. Instead of adding guides to regulate movement, the invention extracts the guiding function by designing the spiral elastic members and valve body interaction to naturally constrain movement to the axial direction through their geometric configuration and force vectors.
Solution Approach 2:
The valve body and spiral elastic members are designed to self-regulate their interaction without external guiding structures. The geometry of the spiral elastic members and their mounting configuration automatically ensures proper axial direction driving through the direction of applied forces, making the system self-guiding.
3Ease of operation
If sliding contact between valve body and guide occurs, then the valve body can be regulated in axial direction, but sludge is generated and transferred in refrigerant causing clogging
Solution Approach 1:
The invention converts the potential harmful sliding contact into beneficial direct contact. By eliminating guides and using the spiral elastic members to directly drive the valve body in the axial direction, the design transforms what would be a harmful sliding interface into a controlled direct driving mechanism that avoids sludge generation while maintaining proper valve regulation.
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 solution provides a low-cost, stable refrigerant cycle operation over long periods by preventing sludge buildup and eliminating the need for axial direction guides, ensuring reliable valve operation.
Implementation Method 1
a solenoid that suctions the valve body to open the small hole
Implementation Method 2
an elastic member urging the valve body to close the small hole, and the elastic member is a disc spring having a plurality of slits formed in a spiral form
Data Source
AI summary
An electronic expansion valve (50) includes a small hole (54a) that expands a refrigerant, a valve body (55c) that opens and closes the small hole, an elastic member (70) that urges the valve body to close the small hole, and a solenoid (61) that suctions the valve body to open the small hole, and expands the refrigerant by opening and closing the valve body. The elastic member is a disc spring in which a plurality of slits (73) formed in a spiral form is provided at mutually equal pitches on the perimeter. Therefore, there is no need for a guide, the occurrence of sludge due to sliding is suppressed, and the electronic expansion valve operates stably over a long period.