Waterproof Junction Box with Integrated Drainage Wall
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Solution Overview
Problem
Existing electrical junction boxes in vehicles face challenges in preventing water intrusion due to complex configurations, particularly with double-wall drainage structures that can allow water to enter through gaps between the body case and upper cover.
Innovation Solution
A simplified configuration featuring a lower case and upper case with a first wall portion in intimate contact with the outer surface and a second wall portion extending upward, where the upper end of the lower case is inserted between the inner and second wall portions with a clearance, facilitating easy assembly and water discharge through inclined and gap structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double-wall drainage structure is used to prevent water intrusion, then water discharge capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the waterproofing function and drainage function into a single integrated structure. The upper case's outer wall serves both as a waterproof barrier and as a drainage path, eliminating the need for separate double-wall drainage structures. Water that enters through the gap is discharged through the outer wall's downward slope, combining protection and drainage in one component.
Solution Approach 2:
The outer wall of the upper case is designed to perform multiple functions: it provides structural support, creates a waterproof seal through intimate contact with the lower case, and simultaneously serves as a drainage channel with its downward slope. This multi-functional design eliminates the need for dedicated drainage structures while maintaining water discharge capability.
2Reliability
If stepped shapes are used at the seam to prevent water intrusion, then water intrusion resistance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The outer wall's downward slope automatically guides water away from the seam area without requiring precisely formed stepped shapes. The gravitational force acting on water combined with the slope creates a self-draining system that compensates for minor variations in seam alignment, reducing the need for high manufacturing precision while maintaining waterproofing effectiveness.
Solution Approach 2:
The patent changes the geometric parameter of the outer wall by introducing a downward slope instead of relying on stepped shapes. This parameter change transforms the waterproofing mechanism from one dependent on precise mechanical interlocking to one that uses gravitational drainage, thereby reducing manufacturing precision requirements while maintaining or improving water intrusion resistance.
3Reliability
If intimate contact between outer wall and lower case is implemented, then water intrusion prevention is improved, but ease of operation during assembly deteriorates
Solution Approach 1:
The upper case is segmented into an inner wall and an outer wall that are spatially separated. The outer wall makes intimate contact with the lower case for waterproofing, while the inner wall maintains a gap to facilitate assembly. This segmentation allows different parts of the upper case to serve different functions: the outer wall for sealing and the inner wall for ease of assembly.
Solution Approach 2:
The patent resolves the assembly conflict by transitioning to a three-dimensional configuration where the inner and outer walls are offset in space. The inner wall is positioned closer to the lower case's opening to facilitate assembly, while the outer wall extends further down to ensure intimate contact for waterproofing. This dimensional arrangement allows both requirements to be satisfied simultaneously.
Data Source
AI summary
Provided is an electrical junction box including a lower case and an upper case joined to the lower case, wherein the upper case includes an inner wall that opposes an inner surface of the lower case and an outer wall that opposes an outer surface of the lower case, the outer wall has a first wall portion that is in intimate contact with the outer surface of the lower case and a second wall portion that extends upward continuously from the first wall portion, and an upper end of the lower case is inserted between the inner wall and the second wall portion with clearances CL1 and CL2.