Miniaturized Electrical Junction Box with Adjustable Divided Portions

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Solution Overview

Problem

Conventional electrical junction boxes for electric vehicles become larger due to increased power flow, necessitating larger dimensions and increased size, which is exacerbated by resin molded covers requiring larger dimensional tolerances.

Innovation Solution

The electrical junction box features a plurality of divided portions with fastening portions that allow for precise positioning and connection, using elongated holes for adjustment, enabling the box to be miniaturized without compromising assembly efficiency or increasing the number of fastening processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the size of the electrical junction box is increased to accommodate higher power flow and larger electric components, then the power handling capability is improved, but the overall device size and dimensional tolerance requirements increase

Engineering Contradiction:
Improvepower handling capabilityVSAvoiddevice size
Core Design Contradiction:
PowerVSVolume of stationary object

Solution Approach 1:

The electrical junction box is divided into a cover and a box body as separate components. The cover can be detached from the box body, allowing for modular assembly and disassembly. This segmentation enables compact design while accommodating power handling requirements through optimized component arrangement rather than simply increasing overall size.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If larger dimensional tolerance is set for resin molded covers, then manufacturing ease is improved, but the external size of the junction box increases due to required margins

Engineering Contradiction:
Improvemanufacturing toleranceVSAvoidexternal dimension
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

Fastening holes are provided in advance at specific positions on both the cover and box body before assembly. These pre-positioned holes enable precise alignment and secure connection, eliminating the need for excessive dimensional tolerance margins. The preliminary placement of fastening features allows tight tolerances while maintaining ease of assembly.

Inventive Principle:
Principle #10Preliminary action

3Volume of stationary object

If the junction box is miniaturized by reducing dimensional tolerance margins, then device size is reduced, but assembly precision requirements increase

Engineering Contradiction:
Improvedevice sizeVSAvoidassembly precision
Core Design Contradiction:
Volume of stationary objectVSManufacturing precision

Solution Approach 1:

The fastening holes are designed to enable self-aligning assembly between the cover and box body. The holes are positioned such that during assembly, the components naturally guide themselves into the correct position through the overlapping hole alignment, reducing the need for high-precision external fixtures or complex assembly procedures despite the miniaturized dimensions.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3539831B1Electrical junction box
Publication Date: 2022.05.04 YAZAKI CORP
  • EP3539831B1 patent drawingFigure 1~2
  • EP3539831B1 patent drawingFigure 3

AI summary

There is provided an electrical junction box which is intended to be miniaturized. The electrical junction box 1 has a plurality of electric components and an installing portion on which the plurality of electric parts are installed. The installing portion is composed of a plurality of divided portions, and has fastening portions for connecting the adjacent divided portions to each other, while adjusting the positions of the adjacent divided portions relative to each other.