Expansion Valve Sub-Valve Segmentation for Weight and Precision
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Solution Overview
Problem
Conventional expansion valves in heat pump type refrigeration cycle systems face difficulties in controlling refrigerant flow rate due to pressure loss and valve leakage, particularly due to the weight and accuracy issues of valve seat members.
Innovation Solution
The expansion valve design incorporates a lightweight sub-valve with a guide member formed by press work and a valve seat member formed by cutting, featuring a disk-like flange portion and ring-like annular boss, crimped and spot-welded for accuracy and stability, with guide plates arranged to prevent foreign particle entrapment and ensure smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the valve seat member is formed by press work to reduce weight, then the ease of operation is improved, but the manufacturing precision of the valve port deteriorates
Solution Approach 1:
The valve seat member is divided into two parts: a guide member formed by press work (for lightweight and smooth operation) and a valve seat portion formed by cutting (for high precision valve port). This segmentation allows each part to be optimized for its specific function while being manufactured by the most suitable method.
Solution Approach 2:
Different manufacturing methods are applied to different parts of the valve seat member: press work is used for the guide member where weight reduction is beneficial, while cutting is used for the valve seat portion where precision is critical. This local quality approach ensures optimal performance in each region.
2Strength
If the valve seat member is made thick and heavy to ensure structural strength, then the reliability is improved, but the ease of operation deteriorates
Solution Approach 1:
The valve seat member is segmented into a guide member and a valve seat portion. The guide member is made thin and lightweight for smooth operation, while the valve seat portion maintains sufficient thickness for structural strength and sealing capability.
Solution Approach 2:
The guide member is designed as a thin-walled structure formed by press work, which provides sufficient structural strength for guiding motion while minimizing weight to enable smooth operation during valve opening and closing.
3Ease of manufacture
If the valve port is formed by press work to simplify manufacturing, then the ease of manufacture is improved, but the manufacturing precision deteriorates causing valve leakage
Solution Approach 1:
The valve seat member is segmented so that the valve port is formed in the valve seat portion by cutting rather than press work. This ensures high manufacturing precision for the valve port while the guide member is still efficiently manufactured by press work.
Solution Approach 2:
The cutting process is applied specifically to the valve seat portion where the valve port is located, ensuring high precision for the critical sealing interface, while other non-critical parts are manufactured by press work for efficiency.
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 reduces pressure loss, enhances flow control, and prevents valve leakage, providing a reliable and stable operation by reducing the sub-valve's weight and improving the accuracy of the valve port, while maintaining low pressure loss across flow directions.
Implementation Method 1
a guide member arranged to slidably contact with an inner circumferential face of the valve housing
Implementation Method 2
when a refrigerant flows from the first port to the second port, the sub-valve is seated on a circumference of the second port due to difference in pressures in the first port and the second port
Data Source
AI summary
There is provided an expansion valve which, by moving the sub-valve in a valve housing, controls the flow rate of a refrigerant in a first flow direction and releases the refrigerant to flow in a second flow direction, wherein the sub-valve is reduced in weight and a valve port is provided with high accuracy. The sub-valve includes a guide member formed by press work and a valve seat member formed by cutting. The sub-valve is seated on a sub-valve seat of a valve seat ring when the pressure in a main valve chamber is high, and is moved away from the sub-valve seat when the pressure in the main valve chamber is low. The sub-valve is reduced in weight by forming the guide member by press work, and the valve port is formed with improved accuracy by forming the valve seat member by cutting.