Compressor Circuit Board Thermal Stress Isolation
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Solution Overview
Problem
The existing electronic circuit apparatus for compressors experiences soldering cracks due to stress caused by the difference in linear expansion coefficients between the circuit board and the case, leading to deteriorated soldering strength and reliability issues across a wide temperature range.
Innovation Solution
The apparatus fixes one corner of the board to the case in the thickness direction, allowing movement in the flattening direction, thereby isolating the board's expansion or contraction from the case's, reducing stress on the soldering portions and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If four corners of the board are fixed to the case by fasteners, then the board is securely held in position, but stress is repeatedly applied to the soldering portion due to thermal expansion differences between the board and case
Solution Approach 1:
The patent divides the fixing function into two independent parts: one corner is fixed to the case to provide positioning stability, while the other three corners are left movable to accommodate thermal expansion. This segmentation allows the board to be securely positioned without transmitting thermal stress to the soldering portions, resolving the contradiction between positioning stability and soldering reliability.
2Manufacturing precision
If the board is rigidly fixed at all corners, then assembly precision is high, but soldering cracks occur due to repeated stress from thermal expansion
Solution Approach 1:
The patent introduces dynamic adaptability to the fixing structure by making three corners movable while keeping one corner fixed. This allows the board to dynamically adjust its position in response to thermal expansion and contraction, preventing the accumulation of stress that would lead to soldering cracks, while still maintaining sufficient assembly precision through the fixed corner.
3Reliability
If the board is allowed to move freely, then thermal stress is reduced, but assembly workability and positioning accuracy deteriorate
Solution Approach 1:
The patent applies local quality differentiation to the fixing structure: one corner is fixed to provide positioning stability and assembly precision, while the other three corners are left movable to reduce thermal stress. This localized approach ensures that each corner serves its specific function, achieving both good assembly workability and high reliability without compromising overall positioning accuracy.
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 approach ensures reliable soldering strength and assembly stability across a wide temperature range, preventing soldering cracks and maintaining circuit integrity, while also improving assembly workability and heat dissipation through the use of thermally conductive materials.
Implementation Method 1
stress is repeatedly applied to a soldering portion of the electronic part due to the difference between linear expansion coefficients of board 20 and case 10 that is caused by heat generated from the electronic part mounted on board 20 or a variation in the outside air temperature of case 10
Data Source
AI summary
An electronic circuit apparatus for a compressor includes a board and a case. One corner of the board is fixed to case such that the board cannot move in the thickness direction and is movable in the flattening direction. According to this structure, even when an electronic part generates heat or outside air temperature of the case varies, the expansion or contraction of the board in the flattening direction is not affected by the expansion or contraction of the case in the flattening direction. Therefore, it is possible to prevent the deformation of the board and stress from being repeatedly applied to a soldering portion of the electronic part. As a result, it is possible to ensure the reliability of soldering strength for a long time.