Bus Bar Connection Structure with Insulation Paper Rotation Prevention
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Solution Overview
Problem
Conventional bus bar connection structures face issues with maintaining electrical and mechanical connections to circuit boards due to thermal stress, which can cause loosening and insulation breakdown, especially when using metal circuit boards for heat dissipation.
Innovation Solution
Incorporating an insulation paper piece between the bus bar and the nut or bolt, along with a rotation-preventing recess to prevent the insulation paper piece from rotating and deforming under torque, ensuring stable electrical and mechanical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulation paper piece is used between the bus bar and the nut or bolt, then electrical insulation is improved, but the insulation paper piece may undergo plastic deformation under thermal stress and torque
Solution Approach 1:
The patent introduces a rotation-preventing part as an intermediary component that works together with the insulation paper piece. This rotation-preventing part prevents the insulation paper piece from rotating during tightening, thereby preventing plastic deformation while maintaining the electrical insulation function. The intermediary component solves the contradiction by adding a mechanical constraint without compromising the insulation property.
Solution Approach 2:
The patent employs a composite structure combining the insulation paper piece with the rotation-preventing part. This composite approach integrates the electrical insulation function of the paper piece with the mechanical rotation-preventing function of the dedicated component, achieving both electrical insulation stability and resistance to deformation under thermal stress and torque.
2Reliability
If the insulation paper piece is disposed between the lower nut and the circuit board or between the bus bar and the head part of the bolt, then electrical connection reliability is improved, but the insulation paper piece may rotate due to torque generated during fastening
Solution Approach 1:
The rotation-preventing part serves as an intermediary between the fastening operation and the insulation paper piece. It intercepts the rotational torque generated during fastening and prevents it from being transmitted to the insulation paper piece, thereby eliminating the rotation issue while maintaining proper electrical connection.
Solution Approach 2:
The rotation-preventing part is designed to engage with the insulation paper piece before the tightening torque is fully applied. This preliminary engagement prevents the insulation paper piece from rotating during the fastening process, ensuring it remains in the correct position throughout the operation.
3Temperature
If metal circuit boards are used for heat dissipation, then thermal management is improved, but thermal shock can cause loosening of the bolt and insulation breakdown
Solution Approach 1:
The insulation paper piece acts as a thermal intermediary between the metal circuit board and the fastening components. It provides electrical insulation and helps distribute thermal stress, reducing the impact of thermal shock on the bolt connection and preventing loosening while maintaining effective heat dissipation through the metal circuit board.
Data Source
AI summary
A bus bar connection structure includes a housing, a circuit board including metal, and a bus bar that are disposed in order from a lower side, a lower nut including metal and disposed in an upper surface-side of the housing in a state in which the lower nut is embedded in the housing, and a bolt including metal. On an upper surface of the circuit board, an insulation layer and a copper foil pattern are formed in order from a lower side. An insulation paper piece is disposed between the lower nut and the circuit board. The bolt is screwed into the lower nut in a state in which the bolt is inserted through the insulation paper piece, the circuit board, the insulation layer, the copper foil pattern, and the bus bar. A rotation-preventing part is further provided, the rotation-preventing part preventing the insulation paper piece from rotating due to torque generated during fastening of the bolt.