Busbar Angle Part for Secure Cable Lug Connection

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Solution Overview

Problem

Existing electric drive systems face reliability issues due to inadequate contact pressure and secure connections, particularly when using cable lugs with smaller wall thicknesses, which can lead to unsafe connections and increased risk of fire.

Innovation Solution

The implementation of a conductor rail angle part with a metallic threaded bushing and a cable lug connection system, where the cable lug is screwed to the busbar angle part at a distance from the contact area, allowing for high contact pressure and secure connections, and enabling the cable to be aligned in various spatial directions, thus preventing contact problems and fires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a cable lug with small wall thickness is directly connected to the busbar, then the device complexity is reduced, but the connection reliability deteriorates due to insufficient clamping force

Engineering Contradiction:
Improveconnection structure complexityVSAvoidconnection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a busbar angle part as an intermediary component between the cable lug and the busbar. This angle part has sufficient wall thickness to provide adequate clamping force when pressed against the busbar by a screw, while the cable lug can be securely attached to it. This mediator resolves the contradiction by enabling reliable connection without requiring the cable lug itself to have thick walls, thus maintaining simplicity while ensuring reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connection structure is segmented into three distinct components: the busbar, the busbar angle part, and the cable lug. This segmentation allows each component to be optimized independently - the busbar for current carrying, the angle part for mechanical support and clamping, and the cable lug for cable attachment. The segmentation enables the thin-walled cable lug to achieve reliable connection through the distributed clamping force provided by the angle part.

Inventive Principle:
Principle #1Segmentation

2Force

If the screw connection presses directly on the cable lug, then the clamping force is sufficient, but the cable lug may deform or fail due to its thin wall thickness

Engineering Contradiction:
Improveclamping forceVSAvoidcable lug strength
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The busbar angle part serves as a mediator that absorbs and distributes the clamping force from the screw. The screw presses the angle part against the busbar, generating sufficient friction and contact force for reliable electrical connection. The cable lug is attached to the angle part with a separate screw, experiencing only localized fastening force rather than the full clamping load. This protects the thin-walled cable lug from deformation while maintaining strong overall connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Length of moving object

If the cable lug connection point is close to the busbar, then the overall connection length is reduced, but the cable cannot be routed in multiple directions

Engineering Contradiction:
Improveconnection lengthVSAvoidcable routing flexibility
Core Design Contradiction:
Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The busbar angle part extends the connection in a spatial dimension perpendicular to the busbar surface. By positioning the cable lug attachment point on the angled surface rather than directly on the busbar, the design enables cable routing in multiple directions (up, down, left, right relative to the busbar) while maintaining a compact overall footprint. This dimensional extension provides routing flexibility without significantly increasing the connection length.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 ensures a reliable and secure electrical connection with high contact pressure, preventing contact issues and fires by maintaining the screw connection integrity and allowing for efficient current distribution with reduced current intensity for signal electronics.

Implementation Method 1

a screw, in particular a screw head of the screw, in particular via a washer, presses the busbar angle part against the busbar and thus presses the busbar against the insulating part

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

a metallic threaded bushing is connected and/or arranged in a material-fit manner, in particular overmolded with plastic material

Methodology Applied
Scientific EffectThreaded Fastening: Screw

Data Source

PatentEP3939395B1Drive system comprising a first module
Publication Date: 2023.08.02 SEW EURODRIVE GMBH & CO KG
  • EP3939395B1 patent drawingFigure 1
  • EP3939395B1 patent drawingFigure 2
  • EP3939395B1 patent drawingFigure 3

AI summary

Drive system comprising a first module, in particular a supply module or axle module, wherein an insulating part is arranged on a sheet-metal part of the first module that functions as a housing part, in which insulating part a metal threaded bushing is connected and/or arranged in a cohesive manner, in particular in a manner encapsulated by injection moulding with plastic, wherein a busbar is received at least partially in an elongate recess, in particular a groove, of the insulating part, wherein a busbar bracket is placed and arranged on the busbar on that side of the busbar which is averted from the insulating part, wherein a screw, in particular a screw head of the screw, presses the busbar bracket part against the busbar, in particular by means of a washer, and said busbar is therefore pressed against the insulating part, wherein a cable shoe which is connected to a cable is screwed onto the busbar bracket part by means of a further screw (3).