Electric Junction Box Stiffness via Partition Wall Ribs
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Solution Overview
Problem
Existing electric junction boxes for motor vehicles face challenges in assembling due to the stiffness issues of their frame-shaped bodies made of synthetic resin, which can deform during molding, making it difficult to insert cassette blocks between partition walls, thereby increasing assembly time and man-hours.
Innovation Solution
The electric junction box incorporates connecting parts, such as connecting beams and walls, that extend between partition walls to enhance stiffness and prevent deformation, allowing easy attachment of cassette blocks, which house electric components, without altering the cassette block's shape or affecting its functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the box body is made of synthetic resin and molded by injection molding with a frame-shaped body part and partition walls, then the manufacturing process is simplified and cost is reduced, but the box body deforms during molding or when taken out from mold, making it difficult to insert cassette blocks
Solution Approach 1:
Ribs are formed protruding from the inner surface of the partition wall in advance during molding, creating preliminary structural support that prevents deformation before the cassette block is inserted. This preliminary structural action ensures dimensional stability is built into the mold itself.
Solution Approach 2:
The solution transitions from a two-dimensional flat partition wall to a three-dimensional structure by adding ribs that protrude from the inner surface. This dimensional enhancement provides structural reinforcement without compromising the injection molding process or increasing material cost.
2Adaptability or versatility
If the distance between partition walls is increased to accommodate more electric components, then the functionality and capacity of the junction box is improved, but the stiffness of the box body deteriorates, causing deformation that makes cassette block insertion difficult
Solution Approach 1:
By adding ribs that protrude from the partition wall inner surface, the structure gains three-dimensional reinforcement. This allows the partition walls to be spaced farther apart horizontally while the ribs provide vertical structural support, maintaining stiffness despite increased component capacity.
Solution Approach 2:
The partition wall structure is segmented into the wall itself and the protruding ribs. This segmentation allows the wall to serve its primary function of separating spaces while the ribs independently provide structural reinforcement, enabling greater wall spacing without losing overall stiffness.
3Adaptability or versatility
If terminal fittings and electric components are attached one by one to the box body, then the assembly is flexible and adaptable, but the assembly time and man-hour required increase significantly
Solution Approach 1:
The junction box is segmented into a box body and detachable cassette blocks. Electric components are pre-assembled on cassette blocks, which can then be quickly attached to the box body. This segmentation enables both flexibility in component arrangement and high efficiency in assembly through modular installation.
Solution Approach 2:
Cassette blocks are prepared in advance with electric components pre-assembled on them. This preliminary assembly action allows multiple components to be installed simultaneously when the cassette block is attached, dramatically reducing assembly time compared to installing each component individually.
4Manufacturing precision
If connecting parts are added to enhance stiffness and prevent deformation, then the dimensional stability is improved, but the device complexity and manufacturing steps increase
Solution Approach 1:
The ribs are merged with the partition wall structure, forming an integrated component rather than a separate attachment. The ribs and partition wall are molded as one piece, providing structural reinforcement without adding separate parts or assembly steps, thus avoiding increased device complexity.
Solution Approach 2:
The partition wall structure combines the base synthetic resin material with integrated rib structures, creating a composite geometry that provides enhanced stiffness. This is achieved through geometric composition rather than material composition, maintaining manufacturing simplicity while improving dimensional stability.
Data Source
AI summary
An electric junction box is provided, by which the cassette block, which mounts the electric components, can be easily attached to between the partition walls of the box body. The electric junction box includes: a box body including a frame-shaped body part and a partition wall partitioning a space within the body part; a cassette block which is received in between the partition walls of the box body so as to be attached to the box body; and a connecting part which connects ends of the partition walls adjacent to each other.