Circuit Assembly with Conductive Rivet Positioning
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Solution Overview
Problem
Conventional circuit assemblies for electrical junction boxes face challenges in productivity due to positional shifts during thermocompression bonding and the risk of improper soldering of connection chips, leading to unreliable electrical connections between the busbar and the control circuit.
Innovation Solution
The integration of a circuit assembly with aligned through holes in the busbar and circuit board, secured by conductive rivets that also serve as electrical connectors, eliminating the need for thermosetting adhesives and enabling precise positioning and electrical connection without thermocompression bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermocompression bonding is used to bond the busbar and circuit board together with an adhesive sheet, then the circuit board can be fixed to the busbar, but the circuit board may move during bonding and cannot be positioned precisely
Solution Approach 1:
Through holes are formed in the busbar and circuit board before bonding, and positioning pins are inserted into these holes to establish precise relative positioning between the busbar and circuit board before the bonding process begins. This preliminary positioning action prevents movement during thermocompression bonding and ensures accurate alignment.
2Reliability
If a connection chip is used as an intermediary to electrically connect the busbar and control circuit, then electrical connection can be achieved, but the connection chip may move while solder is melted and cannot be soldered at the predetermined position
Solution Approach 1:
The connection chip is positioned on the circuit board and temporarily fixed before soldering. Through holes are provided that allow the busbar to be exposed and positioned relative to the connection chip. The positioning pins establish precise alignment between the busbar, connection chip, and control circuit before the soldering process begins, preventing movement during melting and ensuring accurate soldering at the predetermined position.
3Strength
If thermocompression bonding is used to fix the circuit board, then the circuit board can be bonded to the busbar, but the process is time-consuming and reduces productivity
Solution Approach 1:
Through holes and positioning pins are prepared in advance to establish precise positioning between the busbar and circuit board before bonding. This preliminary preparation enables faster alignment and reduces the time required for thermocompression bonding, thereby improving manufacturing efficiency while maintaining bonding strength.
4Strength
If adhesive sheets are used to bond the busbar and circuit board, then the components can be joined, but residual stress causes deformation and cracks
Solution Approach 1:
Through holes are formed and positioning pins are inserted to establish precise mechanical positioning between the busbar and circuit board before bonding. This mechanical positioning structure distributes and reduces residual stress during and after the bonding process, preventing deformation and cracks that would otherwise occur with adhesive-only bonding.
Data Source
AI summary
A circuit assembly includes a circuit board having a control circuit controlling the flow of electric current in a power circuit is integrally formed with a top of a plate-shaped busbar. The circuit assembly includes a busbar that is provided with a first through hole, a circuit board in which both surfaces are provided with circuit patterns and that is provided with a second through hole that is aligned with the first through hole, an insulating sheet that is arranged on one side of the circuit board and is interposed between the busbar and the circuit board, and a conductive rivet that is inserted into the first through hole and the second through hole and fixes the circuit board to a top of the busbar. The rivet includes a body inserted into the first through hole and the second through hole, and a head protruding from the circuit board.