Expansion Valve Contact Surface for Low-Opening Vibration Suppression
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Solution Overview
Problem
Existing expansion valves experience vibrations and abnormal noise due to differential pressure, especially when the opening degree is small, leading to increased fluid force and noise generation.
Innovation Solution
An expansion valve design featuring a vibration-proof spring with a ring spring and a deformation adjustment surface, where the spring's deformation increases as the valve closes, providing enhanced vibration suppression and reduced sliding resistance, especially at small opening degrees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed spring force vibration proof spring is used, then the valve body and actuating bar are suppressed from vibrating at normal opening degrees, but vibration and abnormal noise occur at very small opening degrees where differential pressure is high
Solution Approach 1:
The patent applies the dynamics principle by making the vibration proof spring's spring force variable rather than fixed. The spring force increases as the valve opening degree decreases, which is achieved through the spring's geometric configuration (tapered contact surface) that causes greater deformation at smaller openings. This dynamic adjustment allows the spring to provide stronger vibration suppression exactly when differential pressure and fluid force are highest at small opening degrees, thereby eliminating abnormal noise while maintaining reliability across the full range of valve operation.
Solution Approach 2:
The patent implements parameter changes by varying the spring force parameter based on the valve opening degree. The contact surface between the actuating bar and vibration proof spring is designed with a specific shape (tapered or curved surface) that causes the spring deformation amount to increase as the valve closes. This changes the spring force parameter dynamically, providing higher damping force at small openings where it is most needed to counteract high differential pressure and prevent abnormal noise.
2Object-affected harmful factors
If a vibration proof spring with high spring force is used to suppress vibration at small opening degrees, then abnormal noise is reduced, but sliding resistance increases and smooth operation is compromised
Solution Approach 1:
The dynamics principle resolves this contradiction by making the spring force adaptive rather than constantly high. The spring provides high force only when needed (at small opening degrees with high differential pressure) and reduces force at larger opening degrees where smooth operation is prioritized. This is achieved through the geometric design of the contact surface that naturally varies the deformation amount based on valve position, ensuring high damping where required without compromising overall operational smoothness.
Solution Approach 2:
The local quality principle is applied by concentrating the high spring force effect locally at small opening degrees rather than maintaining it uniformly across all opening degrees. The tapered or curved contact surface design ensures that the increased deformation and spring force occur only in the specific local condition of small valve openings, while the rest of the operating range maintains lower sliding resistance for smooth operation.
3Object-affected harmful factors
If the spring deformation is increased to enhance vibration suppression, then abnormal noise is reduced, but the complexity of the contact surface geometry increases
Solution Approach 1:
The local quality principle addresses this contradiction by applying the complex geometric modification only to the specific contact surface area where it is needed, rather than redesigning the entire spring or actuating bar. The tapered or curved surface is a localized feature on the actuating bar that interfaces with the vibration proof spring, concentrating the geometric complexity only where it generates the beneficial effect of increased deformation at small openings, while keeping the rest of the components simple and manufacturable.
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 effectively suppresses vibrations and abnormal noise at small opening degrees while maintaining smooth operation and controllability at larger opening degrees by adjusting the deformation of the vibration-proof spring.
Implementation Method 1
The contact surface has a shape by which an amount of deformation of the vibration proof spring becomes greater as the valve body goes towards a closing direction of the valve
Data Source
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AI summary
An expansion valve includes a valve main body having a valve chamber therein, a valve body arranged within the valve chamber, a valve body support member supporting the valve body, an urging member urging the valve body toward a valve seat, an actuating bar pressing the valve body in an opening direction of the valve against urging force generated by the urging member, and a vibration proof spring suppressing vibration of the valve body or the actuating bar. The actuating bar has an outer peripheral surface of which a part constitutes a contact surface slidably contacting with the vibration proof spring, and the contact surface has a shape by which the amount of deformation of the vibration proof spring becomes greater as the valve body goes towards a closing direction of the valve.