Thermostat Housing Hook Structure to Prevent Frame Detachment
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Solution Overview
Problem
Conventional thermostat devices with synthetic resin housings experience durability issues and frame detachment due to spring load, as the legs deform and separate, causing the frame to fall off.
Innovation Solution
The thermostat device incorporates a housing with inward-protruding hooking portions featuring an engaged portion and auxiliary portions on the legs, along with R-chamfered edges and ribs, to prevent leg separation and frame detachment by distributing the spring load effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the housing is changed from metal to synthetic resin for cost reduction and weight reduction, then cost and weight are reduced, but durability is reduced and the spring load causes the tips of the legs to deform and separate, causing the frame to fall off
Solution Approach 1:
The hooking portion is divided into multiple functional segments: an engaged portion that contacts the frame, auxiliary portions that provide additional support, and a boundary portion that distributes stress. This segmentation allows each part to perform its specific function optimally, preventing overall leg deformation while maintaining synthetic resin construction
Solution Approach 2:
The hooking portion has non-uniform cross-sectional dimensions with the engaged portion having different width and thickness compared to the auxiliary portions. The boundary portion between the hooking portion and leg has optimized dimensions to distribute stress. This local variation in geometry concentrates structural strength where needed while maintaining overall lightweight construction
2Ease of operation
If the entire tip portion of the legs is protruded inward to form hooking portions, then the frame can be hooked on, but the spring load causes the legs to deform and open, allowing the frame to fall off
Solution Approach 1:
The hooking portion is segmented into an engaged portion for frame contact and auxiliary portions for structural support. This segmentation allows the engaged portion to provide easy frame installation while the auxiliary portions maintain leg stability under spring load
Solution Approach 2:
The engaged portion has asymmetric dimensions relative to the auxiliary portions, with specific width and thickness ratios optimized for frame engagement. The boundary portion has different dimensions from the tip portion, creating an asymmetric geometry that distributes stress away from the leg-root connection while maintaining ease of frame installation
3Reliability
If R-chamfering is applied to the boundary portion and side surfaces, then stress concentration is prevented and durability is improved, but manufacturing complexity increases
Solution Approach 1:
R-chamfering is applied to the boundary portion and side surfaces of the hooking portion, replacing sharp corners with curved transitions. This curvature distributes stress evenly and prevents stress concentration while maintaining relatively simple manufacturing through standard chamfering operations
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 inhibits leg separation and prevents frame detachment, enhancing durability and ease of assembly while maintaining effective temperature control.
Implementation Method 1
a thermo-element having one end disposed inside the housing and performing a telescopic operation in response to temperature
Implementation Method 2
a coil spring 53 for biasing the valve body 52 in a closing direction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a thermostat device from which a frame can be prevented from falling out by suppressing the opening of the legs of a housing. This thermostat device is provided with a housing 1, a valve body 15 provided on an outer periphery of a thermoelement 17 which is inserted inside the housing 1, and a frame 19 supporting one end of a coil spring 16 that urges the valve body 15, wherein: the housing 1 includes a hollow main body portion 20 having an opening at one end, a pair of legs 21, 21, which stand upright from the opening edge of the main body portion 20, and hook portions 21a which are formed projecting inward from distal end portions of the legs 21, and on which the frame 19 catches; each hook portion 21a includes an engaged portion positioned in the center in the width direction of the leg 21, and auxiliary portions which are continuous with the engaged portion and which are positioned at both ends in the width direction of the leg 21; an end surface c of the engaged portion on the leg 21 root side thereof is positioned farther from a distal end of the leg 21 than end surfaces a, b of the auxiliary portions on the leg 21 root side thereof; and the frame 19 abuts the end surface c of the engaged portion.