Vehicle Junction Box Waterproofing via Asymmetric Lapping
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Solution Overview
Problem
Conventional electrical junction boxes in vehicles are prone to water ingress, particularly at inclination portions, leading to water splashing into the internal components, and the use of packing to prevent this increases component and assembly costs.
Innovation Solution
The electrical junction box design features a larger lapping amount at the inclination portion compared to the lower portion, allowing water to enter and then slowly drain out by its own weight without the need for packing, utilizing a double wall structure with an exterior and interior wall to direct water flow and drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a packing is attached between the exterior wall and interior wall to prevent water ingress, then waterproofing reliability is improved, but component cost and assembly cost increase
Solution Approach 1:
The invention extracts and eliminates the packing component from the waterproofing system. Instead of using a separate packing element attached between the exterior and interior walls, the design relies on the geometric configuration of the inclination portion and lapping amount to achieve waterproofing without this additional component, thereby reducing cost and assembly complexity while maintaining reliability
Solution Approach 2:
The structure serves its own waterproofing function through its geometric design. The inclination portion with its specific lapping amount creates a self-draining configuration that uses gravity and surface geometry to prevent water ingress, eliminating the need for separate waterproofing components like packing
2Reliability
If the lapping amount at the inclination portion is increased to prevent water ingress, then waterproofing reliability is improved, but the complexity of the frame and cover structure increases
Solution Approach 1:
The invention applies local quality by creating a non-uniform lapping amount distribution along the peripheral wall. Specifically, the inclination portion has a larger lapping amount than the lower or higher portions, concentrating the waterproofing function where water ingress is most likely to occur while maintaining simpler geometry elsewhere
Solution Approach 2:
The design employs asymmetry in the lapping amount configuration, where the lapping amount varies at different portions of the peripheral wall. The inclination portion features an asymmetrically larger lapping amount compared to other sections, creating an optimized waterproofing profile that prevents water ingress without requiring symmetric complexity throughout the entire structure
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
This design effectively prevents water from blowing into the frame's internal components, reducing the risk of water ingress and eliminating the need for packing, thus lowering costs and enhancing waterproofing without additional components.
Implementation Method 1
a lapping amount at the inclination portion is formed larger than a lapping amount between the peripheral wall and the cover at the lower portion, so that even if water enters from the engaged portion between the frame and the cover, the water slowly falls by its own weight
Data Source
AI summary
An electrical junction box provides a frame and a cover that covers an opening portion of the frame. There is a difference of elevation in an edge of the frame, and the edge includes a lower portion, a higher portion, and an inclination portion. A double wall formed of an exterior wall and an interior wall and positioning the edge of a peripheral wall between the exterior wall and the interior wall is provided to the cover. There is a difference of elevation in the edge of the interior wall similarly the frame, and the edge includes the lower portion, the higher portion, and the inclination portion. Also, a lapping amount between the peripheral wall and the interior wall at the inclination portion is formed larger than a lapping amount at the lower portion.