Conical Rivet Busbar Joint for Thermal Expansion and Vibration

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Solution Overview

Problem

Existing busbar connections require multiple parts, are time-consuming to assemble, and lack vibration resistance, with conical washers providing insufficient thermal expansion compensation and requiring maintenance checks.

Innovation Solution

A rivet with an integrated conical washer that acts as a spring, ensuring proper surface pressure and thermal expansion compensation, allowing for faster assembly and quality control through visual inspection, and reducing the number of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard bolted joints with conical washers are used, then thermal expansion compensation is provided, but the assembly is time-consuming and requires multiple quality checks

Engineering Contradiction:
Improvethermal expansion compensationVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent combines the fastening function (bolt) and the thermal expansion compensation function (conical washer) into a single integrated rivet component. The rivet features a conical working surface that directly contacts the busbar, eliminating the need for separate conical washers and reducing assembly steps while maintaining thermal expansion compensation capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rivet is designed to perform multiple functions simultaneously: mechanical fastening, electrical conduction, and thermal expansion compensation. The conical surface provides both the fastening mechanism and the compliant feature for thermal movement, while the rivet body conducts electricity between busbars

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Stress or pressure

If multiple parts are used in standard joints, then proper surface pressure can be maintained, but the device complexity increases and quality control becomes more difficult

Engineering Contradiction:
Improvesurface pressureVSAvoidnumber of parts
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The patent integrates the functions of multiple components (bolt, conical washer, nut) into a single rivet component. The rivet includes an integrated conical working surface that maintains proper surface pressure on the busbar while reducing the total part count and simplifying quality control

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If standard rivets are used, then assembly is faster than bolted joints, but vibration resistance is insufficient without additional features

Engineering Contradiction:
Improveassembly speedVSAvoidvibration resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent combines the speed advantages of riveting with the vibration resistance of bolted joints by integrating a conical working surface directly onto the rivet. This allows for rapid single-step installation while the conical geometry provides mechanical interlocking that resists vibration-induced loosening

Inventive Principle:
Principle #5Merging (Combining)

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

The rivet provides a reliable, vibration-resistant connection with improved thermal stability, reducing assembly time by up to 50% and eliminating the need for additional quality checks.

Implementation Method 1

the collar is made such that is capable for elastic deformation during assembly and is configured to act as a spring

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The rivet is combined with the conical washer. Such combination would minimize a negative impact of a thermal elongation on joint properties

Methodology Applied
Scientific EffectThermal expansion compensation: Thermal Expansion

Data Source

PatentEP4246003B1A rivet, a busbar joint of electrical cabinets comprising a rivet
Publication Date: 2025.10.15 ABB (SCHWEIZ) AG
  • EP4246003B1 patent drawingFigure 1
  • EP4246003B1 patent drawingFigure 2
  • EP4246003B1 patent drawingFigure 3

AI summary

The present disclosure relates to an electrical joint used to connect busbars and method to making it. A busbar joint of electrical cabinets comprising at least two electrical busbars (5, 6), namely a first electrical busbar (5) and a second electrical busbar (6), with a hole in each electrical busbar (5, 6), electrically and mechanically connected with each other characterized in that comprises at least one rivet, wherein each rivet comprises a top head (1), a collar (2), a pin (3) and a bottom head (4) wherein the top head (1) is connected to a first end (3a) of the pin (3) through the collar (2) wherein the collar (2) has a conical shape, wherein an outer diameter of the collar (2) is facing toward the pin (3) and the bottom head (4) is placed on a second end (3b) of the pin (3); the pin (3) is placed into the holes of electrical busbars (5, 6) in such a way that the collar (2) is in contact with the first electrical busbar (5) and the bottom head (4) is in contact with the second electrical busbar (6), wherein the collar (2) is elastically deformed.