Resin-Sealed ECU Layout to Reduce Control Board Warping
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Solution Overview
Problem
The existing electronic control units face issues with warping and deformation due to molding pressure from sealing resin, leading to reduced reliability and increased costs, as the size reduction of the metal base results in a smaller fixed area for the electronic circuit board.
Innovation Solution
An electronic control unit design where the enclosure has a resin volume imbalance, with a larger volume on one surface side than the other, and a gate mark is formed to ensure even resin flow, reducing pressure differences and warping, and the control board is arranged to partially overlap the gate mark projection, allowing for balanced resin charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the metal base size is reduced to decrease weight and cost, then the fixed area of the electronic circuit board is reduced, but the electronic circuit board is more likely to warp and deform under molding pressure
Solution Approach 1:
The gate mark is designed with asymmetric resin volume distribution, having a larger volume on one surface side of the control board and a smaller volume on the other surface side. This asymmetric configuration allows the resin to exert balancing pressures on both surfaces of the control board during molding, preventing warping even when the metal base size is reduced.
2Ease of manufacture
If the metal base size is reduced to decrease cost, then the fixed area of the electronic circuit board is reduced, but the control board stability under molding pressure deteriorates
Solution Approach 1:
The gate mark employs asymmetric resin volume distribution to achieve stable control board positioning during molding. The larger resin volume on one side and smaller volume on the other side create balanced pressure distribution, maintaining control board stability while allowing reduction of the metal base size for cost efficiency.
Solution Approach 2:
The gate mark structure provides localized pressure distribution through its asymmetric design, with different resin volumes on opposite sides of the control board. This local quality variation in resin distribution ensures uniform pressure application on the control board surface, preventing deformation during the molding process.
3Reliability
If sealing resin is charged to complete molding, then the control board is sealed and protected, but molding pressure causes warping when the fixed area is small
Solution Approach 1:
The gate mark is configured with asymmetric resin volumes on opposite sides of the control board. This asymmetric design ensures that during resin charging, the pressure distribution on both surfaces of the control board is balanced, preventing warping and maintaining manufacturing precision while providing effective sealing protection.
Solution Approach 2:
The invention changes the resin volume parameter in the gate mark design, creating a deliberate imbalance with larger volume on one side and smaller volume on the other. This parameter modification optimizes the pressure distribution during molding, ensuring both effective sealing and control board flatness.
Data Source
AI summary
Reliability is to be improved. A control board 2 on which an electronic component 1 is mounted and an enclosure 3 in which the control board 2 is sealed with sealing resin 5 are included, wherein the enclosure 3 has a shape in which a volume of resin on one surface side of the control board 2 is larger than a volume of resin on the other surface side, a gate mark 21a is formed in the enclosure 3, a length of the gate mark 21a in a thickness direction of the control board 2 is larger than a thickness of the control board 2, the control board 2 is located such that a side surface partially overlaps a projection region of the gate mark 21a, and the control board 2 is arranged toward the other surface side relative to a center of the gate mark 21a.