Thermostat Device Segmented Case Design
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Solution Overview
Problem
Conventional thermostat devices for automobile engines face challenges in assembly and durability due to deformation of the stainless steel case, leading to inadequate sealing and increased costs, with issues in machining and assembly affecting the reliability and water-tightness of the thermal expansion unit.
Innovation Solution
A thermostat device design featuring a thermal expansion unit with a piston and guide member offset in both axial and diametrical directions within the element case, utilizing a seal member and O-ring to prevent deformation and ensure proper sealing, and using a coil spring bearing member to alleviate stress on the element case, allowing for easier assembly and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the element case is made of stainless steel material with direct pushing structure, then the weight is reduced and fuel efficiency is improved, but machining and assembly difficulties arise leading to increased cost
Solution Approach 1:
The element case is divided into multiple portions with different functions: a first portion for receiving the thermal expansion unit, a second portion for guiding the first valve, and a third portion for inserting the guide member and seal member. This segmentation allows each portion to be optimized independently for its specific function, resolving the manufacturing and assembly difficulties while maintaining the weight benefits of stainless steel material.
Solution Approach 2:
Different portions of the element case are given different local qualities and dimensions. The first portion has a diameter configured for receiving the thermal expansion unit, the second portion has a smaller diameter for guiding the first valve, and the third portion has specific dimensions for inserting the guide member and seal member. This local quality differentiation enables proper assembly and machining while maintaining overall weight reduction.
2Ease of operation
If the first valve is fitted onto the element case, then the cooling water route is controlled, but the seal member cannot maintain seal due to case deformation
Solution Approach 1:
The guide member and seal member are inserted into the element case before the first valve is fitted. The guide member is positioned in advance to guide the first valve during assembly, and the seal member is installed beforehand to ensure proper sealing. This preliminary action prevents case deformation from compromising the seal, as the sealing components are already in place and properly positioned before the valve fitting process.
Solution Approach 2:
The guide member acts as an intermediary between the element case and the first valve. It is inserted into the case and provides a guiding surface that directs the first valve during assembly, preventing misalignment and deformation of the case. The guide member mediates the interaction between the valve and case, ensuring proper positioning and maintaining sealing integrity.
3Ease of operation
If the guide member is inserted into the element case, then the piston is held, but assembly becomes complicated due to interference with first valve fitting
Solution Approach 1:
The guide member is inserted into a third portion of the element case that is offset from the second portion where the first valve is fitted. This spatial separation in different dimensions (different portions of the case) allows both the guide member and first valve to coexist without interference, simplifying the assembly process while maintaining the piston guidance function.
4Loss of substance
If the element case diameter is reduced for guide member insertion, then material usage is reduced, but the first valve cannot be properly fitted
Solution Approach 1:
The element case is segmented into different portions with different diameters optimized for specific functions. The first portion has a diameter suitable for receiving the thermal expansion unit, the second portion has a reduced diameter for guiding the first valve with minimal material, and the third portion has specific dimensions for the guide member and seal member. This segmentation reduces overall material usage while ensuring each component can be properly fitted.
Solution Approach 2:
The element case exhibits local quality variations in diameter across different portions. The second portion has a smaller diameter than the first portion, optimized for guiding the first valve with minimal material. This local quality differentiation allows proper valve fitting while reducing material usage in the specific region where the valve interacts with the case.
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 enhances the assembly process, improves the reliability and durability of the thermostat device by preventing deformation and ensuring proper sealing, while reducing the number of parts and production costs, and allows for a thinner, more responsive thermal element with reduced material usage.
Implementation Method 1
a thermal expansion unit that expands with a temperature increase and contracts with a temperature decrease, the thermal expansion unit built into an element case so as to be susceptible to effects of heat from outside the element case
Data Source
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AI summary
A thermo-element for a thermostat device includes an element assembly and is configured in such a manner that the themo-element has a simple structure which allows the themo-element to be easily assembled and to be small-sized and lightweight and that the thermoelement has excellent properties of durability, wear resistance, etc. A thermo-element (21) having incorporated in a case (31) a heat expansion body (32) which expands and contracts according to a change in temperature comprises: a piston (33) disposed along the axis direction within the case, having an inner end exposed to the inside of the heat expansion body, protruding outward from the opening on one end side of the case, and advancing and receding as the heat expansion body expands and contracts; a guide member (34) which is disposed within the case by being inserted from the opening on said side of the case and slidably holds the piston; and a poppet-like first valve element (poppet-like member) (22) fitted to an outside portion of the case, said outside portion being that which is located near the opening on said side of the case, and opening and closing a fluid flow path. A fit-in section (41) of the first valve element, said fit-in section being that which is fitted to the outside portion of the case, and insertion sections (42,43) of the guide member which are inserted within the case are arranged so as to be positionally displaced fiom each other in the axis direction and radial direction of the case.