Resin Housing Control Valve Thermal Expansion Mismatch
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Solution Overview
Problem
Conventional control valves with resin-made housing and metal screws experience thermal expansion issues due to differing linear expansion coefficients, leading to plastic deformation and axial force deterioration of the screws.
Innovation Solution
A control valve design featuring a resin housing with metal connection pipes and fastening members, where the connection pipes and fastening members are made of materials with lower linear expansion coefficients than the housing, reducing thermal expansion differences and maintaining axial force integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the connection pipe is made of synthetic resin to match the housing material, then the overall structure can be made of the same material for ease of manufacture, but the connection pipe expands more than the metal screw due to thermal expansion, causing the screw to be pulled outward and deteriorating its axial force
Solution Approach 1:
The patent applies local quality by making the connection pipe and fastening member materials different from the housing material. Specifically, when the housing is made of synthetic resin, the connection pipe is made of metal with a lower linear expansion coefficient, and the fastening member is made of a material with an even lower linear expansion coefficient. This localized material differentiation resolves the thermal expansion mismatch problem while maintaining ease of manufacture through standardized material selection for each component.
Solution Approach 2:
The patent applies parameter changes by carefully selecting materials with specific linear expansion coefficient values. The connection pipe material is chosen to have a lower linear expansion coefficient than the housing, and the fastening member material is chosen to have an even lower linear expansion coefficient. This parameter optimization ensures that during thermal expansion, the fastening member expands less than the connection pipe, preventing axial force deterioration.
2Reliability
If the fastening member is made of metal with lower linear expansion coefficient than the connection pipe, then thermal expansion difference is reduced, but the material selection becomes more restrictive and complex
Solution Approach 1:
The patent systematically addresses material selection complexity by establishing clear parameter hierarchies: the connection pipe material must have a lower linear expansion coefficient than the housing, and the fastening member material must have a lower linear expansion coefficient than the connection pipe material. This structured parameter approach simplifies the selection process despite the multiple material requirements.
Solution Approach 2:
The patent employs composite material strategy by combining different materials (synthetic resin for housing, metal for connection pipe, and specialized alloy for fastening member) each optimized for their specific function. This composite approach allows each component to be made from the most suitable material for its thermal and mechanical requirements, resolving the reliability issue while managing complexity through functional specialization.
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 configuration effectively suppresses axial force deterioration and plastic deformation of screws, enhancing the reliability and longevity of the control valve by minimizing thermal expansion-induced stress.
Implementation Method 1
thermal expansion due to temperature variation occurs... linear expansion coefficient... thermal expansion of the connection pipe causes the screw to be pulled outward
Data Source
AI summary
A control valve for use in a heat exchange circuit of an engine of an automobile includes a housing and a connection pipe. The housing includes a communication port structured for introduction or discharge of fluid. The connection pipe is fastened to the communication port of the housing with a fastening member. The housing is made of resin. Each of the connection pipe and the fastening member is made of material, such as metal, less in linear expansion coefficient than the housing.