Resin Molded Circuit Board Casing Vibration Noise Reduction
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Solution Overview
Problem
Conventional electronic circuit apparatuses face challenges in preventing noise and damage from vibrations, as well as heat management and increased construction member count, particularly in vehicle-mounted engine ECUs.
Innovation Solution
An electronic circuit apparatus with a resin-molded casing that seals the circuit board and connector, incorporating a heat radiation portion protruding from the casing to efficiently dissipate heat and reduce vibration-induced noise, while integrating attachment portions to minimize construction members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the circuit board is fixed in the casing with a cover attached after assembly, then the connector can be partially exposed for external connection, but foreign matter such as water can enter the casing and vibration causes noise and component deviation
Solution Approach 1:
The patent combines the protective casing and circuit board fixation into a single integrated resin molded component. The circuit board is embedded directly into the resin casing during molding, eliminating the need for separate cover attachments and internal fixings. This merging of functions provides complete sealing against foreign matter while preventing vibration-induced noise and component deviation, all without increasing the number of construction members.
2Reliability
If multiple construction members are used to seal and fix the circuit board, then protection against vibration and foreign matter is improved, but mounting labor and assembly complexity increase
Solution Approach 1:
The circuit board is positioned and fixed into the resin casing during the molding process itself, before the casing hardens. This preliminary action of embedding the circuit board during manufacturing eliminates the need for subsequent assembly steps of attaching covers and fixings. The single-step molding process simultaneously achieves sealing, fixation, and structural integrity, dramatically reducing mounting labor and assembly complexity while maintaining high reliability.
3Reliability
If the circuit board is sealed in a box-shaped casing with air ambient, then protection is provided, but heat generated by circuit components cannot be radiated effectively
Solution Approach 1:
The patent replaces the traditional box-shaped rigid casing with a resin molded casing that incorporates a heat radiation portion. This resin structure acts as both protective shell and heat dissipation medium. The heat radiation portion is specifically designed with surface characteristics that enhance thermal radiation, allowing heat from circuit components to be effectively transferred to and radiated from the casing surface, thus maintaining protection while solving the heat dissipation problem.
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 effectively restricts vibration-induced noise and damage, maintains circuit component temperatures within operational ranges, and reduces the number of construction members and assembly labor, enhancing reliability and heat management.
Implementation Method 1
a casing made of a resin. The casing is molded to seal a part of the connector, and a whole of the circuit board and the circuit components in the resin
Implementation Method 2
the casing has a heat radiation portion which protrudes outward from the casing. The circuit components include an electronic unit which generates heat. The heat radiation portion is arranged at a position corresponding to that of the electronic unit
Data Source
AI summary
An electronic circuit apparatus has a casing, a circuit board at which electronic members and power transistors are mounted, and a connector for connecting the circuit board with an external electrical circuit. The casing is insertion-molded by a resin, with the circuit board where the electronic members, the power transistors and the connector have been mounted being held at a predetermined position in a die for molding the casing through the resin. Thus, in the electronic circuit apparatus, damage to circuit components and noise due to a vibration excitation can be restricted, without increasing the number of construction members of the electronic circuit apparatus.