Rotational Casing Packing Alignment for Automotive Waterproofing
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Solution Overview
Problem
Existing electrical connection boxes for automobiles face challenges in ensuring waterproof capability and airtightness due to misalignment of the cover during rotational movement, which affects the sealing of the packing against the frame peripheral wall.
Innovation Solution
A casing design with a packing groove in the cover and a position adjusting portion on the frame peripheral wall, allowing for precise alignment and pressing of the packing against the edge, enhanced by a rib-shaped position adjusting portion and taper guide for improved workability and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a packing is assembled on the cover to ensure waterproof capability and airtightness, then sealing performance is improved, but when the cover is misaligned during rotational movement, the center position of the packing is not reliably pressed against the frame peripheral wall, compromising waterproof capability and airtightness
Solution Approach 1:
The packing groove is pre-formed with a specific shape and position on the cover, and the position adjusting portion is pre-formed on the frame peripheral wall. These preliminary structural preparations ensure that when the cover is assembled and rotated, the packing groove is automatically positioned and pressed against the frame peripheral wall at the correct location, even if misalignment occurs during assembly. This preliminary action eliminates the need for precise manual alignment during assembly.
Solution Approach 2:
The position adjusting portion acts as an intermediary element between the frame peripheral wall and the packing groove. It mediates the alignment relationship by providing a reference surface that guides the packing groove into proper contact with the frame peripheral wall. This intermediary structure ensures reliable positioning without requiring high precision in the cover's rotational movement or assembly alignment.
2Reliability
If the position of the packing groove is adjusted to ensure reliable pressing against the frame edge, then waterproof capability and airtightness are improved, but the structure of the molding die becomes more complex
Solution Approach 1:
The position adjusting portion is segmented from the main body of the frame peripheral wall, forming a distinct functional element. This segmentation allows the position adjusting portion to be designed and formed independently with a specific shape (such as a protrusion or ridge) that can be easily integrated into the molding die. The segmented structure simplifies the molding die design compared to attempting to create a complex integrated position adjustment mechanism.
Solution Approach 2:
The position adjusting portion is located only at the specific location where positioning is needed, rather than throughout the entire frame structure. This local quality approach means that only a small portion of the molding die needs to be designed to create the position adjusting portion, keeping the overall molding die structure simple while achieving the desired positioning function at the critical location.
3Reliability
If a rib-shaped position adjusting portion with taper guide is provided, then waterproof capability and airtightness are ensured with minimal resin material and workability is improved, but the structure becomes more specific and detailed
Solution Approach 1:
The position adjusting portion is formed with a taper (inclined surface) rather than a vertical or abrupt edge. This curved or inclined geometry allows the packing groove to be guided smoothly onto the frame peripheral wall during assembly, improving workability. The taper shape is a simple geometric form that can be easily created in the molding die without adding significant complexity, while effectively ensuring proper positioning and sealing.
Data Source
AI summary
A wire harness wired to a vehicle has an electrical connection box at a terminal thereof. The electrical connection box includes an electronic component block to which a plurality of electronic components are assembled and a casing to be an assembly destination of the electronic component block. The casing has a structure in which an upper cover rotates and moves to cover an upper opening portion surrounded by an edge of a frame peripheral wall. The casing includes the frame peripheral wall having the upper opening portion, the upper cover covering the opening portion by rotational movement, and a packing to be assembled to the upper cover. The packing is assembled to a packing groove formed in the upper cover. The frame peripheral wall has a position adjusting portion for adjusting the position of the packing groove with respect to the edge of the frame peripheral wall.