Busbar Filter Cover Fastening to Reduce Stress and Abrasion

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Solution Overview

Problem

Existing busbar units with integrated filter devices face challenges in manufacturing complexity, size, and mechanical stability, particularly due to complex molds and processes, and conventional fastening methods cause mechanical stress and abrasion.

Innovation Solution

A positive-locking connection between a cover and busbar assembly is implemented using an elastically deformable fixing device, which engages behind the busbars, along with restoring elements to secure the filter device in place, reducing mechanical stress and allowing for automated assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the filter device is positively fitted into the housing to ensure mechanical stability, then the filter device is securely fixed, but the cover and busbar assembly are subjected to undesirable mechanical loads

Engineering Contradiction:
Improvemechanical stabilityVSAvoidmechanical loads
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

A dedicated fixing device is introduced as an intermediary component between the filter device and the busbar assembly. This fixing device includes fixing elements that engage with the busbar assembly, transferring mechanical loads away from the cover and busbars to specialized fastening structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fixing device is segmented into multiple fixing elements distributed along the filter device. This segmentation allows the mechanical loads to be distributed across multiple engagement points with the busbar assembly, reducing stress concentration on any single component.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If spring elements are used to fix the common-mode filter inside the housing, then the filter is securely mounted, but abrasion occurs which can accumulate and lead to malfunctions

Engineering Contradiction:
Improvefilter mountingVSAvoidabrasion
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The fixing elements are designed as simple, robust structures that engage with the busbar assembly without requiring complex spring mechanisms. By using straightforward mechanical engagement features rather than reusable spring elements, the design eliminates the abrasion problem while maintaining effective mounting.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If the cover is designed to bear mechanical loads to restrict movement, then the filter device is secured, but the cover structure becomes more complex and massive

Engineering Contradiction:
Improvemovement restrictionVSAvoidcover structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The function of bearing mechanical loads and restricting filter device movement is extracted from the cover and transferred to a dedicated fixing device. The cover is reduced to its primary function of enclosing the filter device, while the fixing device handles the mechanical fastening and load-bearing responsibilities.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This solution simplifies manufacturing, reduces mechanical stress, and prevents abrasion, while ensuring stable and secure attachment of the filter device to the busbar assembly.

Implementation Method 1

The fixing device has several fixing elements which are elastically deformable when the cover is placed on top, allowing it to snap into place behind the busbar assembly

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3977826B1Device having a bus bar assembly, a filter device and a cover, associated production method, and power converter and drive apparatus
Publication Date: 2025.11.19 VALEO EAUTOMOTIVE GERMANY GMBH
  • EP3977826B1 patent drawingFigure 1
  • EP3977826B1 patent drawingFigure 2
  • EP3977826B1 patent drawingFigure 3~4

AI summary

The invention relates to a device (1), comprising: a bus bar assembly (2), which has two bus bars (3, 4); and a filter assembly (5), comprising a filter device (7), which surrounds the bus bars (3, 4) in a filter segment (6), and a cover (8), which covers the filter device (7), wherein the cover has a fastening device, which is designed to engage behind the bus bar assembly (2) in order to fasten the cover (8) to the bus bar assembly (2).