Electrical Bushing Joint With Compressible Thermal Stress Buffer
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Solution Overview
Problem
Electrical bushings face premature failure due to mechanical stress caused by different thermal expansion coefficients of materials used in the locking compound and interfaces, especially in outdoor applications with varying temperatures.
Innovation Solution
Incorporating a compressible material within the joint between the flange and core, which compresses or expands to mitigate thermal expansion effects, allowing for a wider temperature range and higher load tolerance, and enabling the use of more durable locking compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a locking compound is used to fixate the core and flange, then the joint strength is improved, but the reliability deteriorates due to mechanical stress from thermal expansion differences
Solution Approach 1:
A compressible material is introduced as an intermediary element between the core and flange, filling the joint volume alongside the locking compound. This mediator absorbs thermal expansion differences through compression and expansion, preventing stress transmission to the locking compound and interface joints, thereby maintaining reliability while preserving strength
Solution Approach 2:
The compressible material changes its volume parameter in response to thermal expansion and contraction of the core and flange. By adjusting its compression state, it compensates for dimensional changes, preventing stress buildup that would otherwise compromise joint reliability
2Adaptability or versatility
If the bushing operates in a wide temperature range, then the adaptability is improved, but the reliability deteriorates due to repeated thermal stress
Solution Approach 1:
The compressible material is pre-installed in the joint volume to provide cushioning before thermal stress occurs. During temperature cycles, it proactively absorbs expansion and contraction forces, preventing stress accumulation that would lead to premature failure, thus enabling reliable wide-temperature operation
3Strength
If a rigid locking compound is used, then the joint strength is improved, but the ease of manufacture deteriorates due to sensitivity to thermal expansion
Solution Approach 1:
The compressible material serves as a buffer intermediary that decouples the rigid locking compound from thermal expansion effects. This allows the use of rigid, high-strength locking compounds without worrying about thermal stress sensitivity, simplifying manufacturing requirements
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 solution enhances the long-term reliability and mechanical properties of electrical bushings by reducing mechanical stress and allowing operation in a broader temperature range and under higher loads, while enabling the use of more robust locking compounds.
Implementation Method 1
Due to different coefficients of thermal expansion of the materials used for the bushing, repeated mechanical stress within the cured locking compound and at interfaces to the core and the flange may result in premature failure of the joint
Implementation Method 2
the compressible material being configured to compress or expand in response to a change in the volume of the joint
Data Source
AI summary
An electrical bushing is specified, the bushing including a flange with a lower part and an upper part affixed to one another and further including a core surrounded by the flange, wherein the flange is affixed to the core by a locking compound disposed in a volume of a joint between the flange and the core, and wherein the volume of the joint further includes a compressible material, the compressible material being configured to compress or expand in response to a change in the volume of the joint.Furthermore, a method of producing an electrical bushing is specified.