Shielded Junction Box Assembly for EMC Sealing and Fewer Parts
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Solution Overview
Problem
Existing electrical junction boxes for high voltage harnesses in vehicles require multiple parts and are costly, lacking a robust construction, effective EMC protection, and adequate water tightness.
Innovation Solution
A method involving an everted braided shield of a cable end surrounded by an isolating jacket, secured in a conductive housing with protrusions and conductive adhesive, eliminating the need for ferrules and additional components, while using complementary half-shells for improved fixation and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ferrules and additional components are used to secure the braided shield, then reliable electrical contact and mechanical fixation are achieved, but the number of parts increases and manufacturing cost rises
Solution Approach 1:
The patent combines multiple functions into the housing structure itself: the retainer section provides both mechanical fixation (through protrusions pressing against the everted braided shield) and electrical contact (through conductive adhesive), eliminating the need for separate ferrules and fasteners. This merging of functions reduces part count while maintaining reliability
Solution Approach 2:
The housing is designed as a multi-functional component that simultaneously provides mechanical support, electrical shielding, water tightness, and cable fixation. The retainer section integrates both clamping and electrical contact functions, making the housing a universal solution that replaces multiple specialized components
2Reliability
If traditional multiple-component assembly is used, then robust construction and EMC protection are achieved, but manufacturing time and cost increase
Solution Approach 1:
The conductive adhesive serves multiple purposes simultaneously: it provides electrical contact between the braided shield and housing for EMC protection, acts as a sealant for water tightness, and contributes to mechanical fixation. This multi-functionality achieves robust construction without additional components or steps
Solution Approach 2:
The braided shield is everted beforehand to create an everted section that can be directly received by the retainer section. This preliminary preparation enables the shield to be fixed and electrically contacted in a single assembly operation, improving manufacturing speed while maintaining EMC protection
3Strength
If ferrules and additional fixation components are used, then mechanical fixation strength is improved, but the number of parts and manufacturing complexity increase
Solution Approach 1:
The protrusions in the retainer section are designed to directly press against the everted braided shield, providing mechanical fixation without additional fasteners. The conductive adhesive further strengthens this connection, creating a robust fixation system that is simpler to manufacture than traditional multi-component assemblies
Solution Approach 2:
Instead of attaching a ferrule to the end of the braided shield, the patent inverts the approach by everting the shield itself and having the housing protrusions press against it. This inversion eliminates the need for separate fixation components while maintaining or improving fixation strength
4Reliability
If traditional sealing methods are used, then water tightness is achieved, but additional sealing components and assembly steps are required
Solution Approach 1:
The conductive adhesive serves dual functions as both an electrical conductor and a water seal. By applying the adhesive in the gap between the retainer section and the everted braided shield, it simultaneously ensures electrical contact and prevents water ingress, eliminating the need for separate sealing components
Solution Approach 2:
The adhesive material is used universally for multiple purposes: electrical conduction, mechanical bonding, and water sealing. This multi-functional use of a single material reduces the number of specialized components needed while achieving reliable water tightness
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
Reduces part count and manufacturing costs while ensuring robust construction, effective electromagnetic interference shielding, and enhanced water tightness without additional parts.
Implementation Method 1
an electrically conductive adhesive is applied to the retainer section and/or to the everted braided shield section of the cable end... an electrically conductive adhesive is provided between the retainer section and the everted braided shield section of the cable end such as to fixedly secure the cable end in the housing wherein the housing and the braided shield are connected in an electrically conductive manner
Implementation Method 2
said retainer section having at least one protrusion for urging against the inverted braided shield section... the protrusion which is integrally provided with the housing and the electrically conductive adhesive are sufficient to secure the cable end in the housing
Implementation Method 3
an electrically conductive adhesive is applied to the retainer section and/or to the everted braided shield section of the cable end... the cable end is fixedly secured in the housing after the housing has been closed and the adhesive has cured
Data Source
Figure 1
AI summary
An electrical junction box comprises an electrically conductive housing and at least one cable end wherein an everted braided shield section of the cable end is received in a retainer section of the housing and an electrically conductive adhesive is provided.