Floating Retention Nut for Busbar Clamp Load Control

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Solution Overview

Problem

Existing busbar connection systems face mechanical failure and high contact resistance due to improper clamp load, especially when dealing with busbars of varying thicknesses, which can lead to ohmic heating and open circuit events.

Innovation Solution

A floating retention nut system that axially moves along a fastener length to accommodate varying busbar thicknesses, ensuring a consistent clamp load and reducing contact resistance by using a dielectric overmold and a fastener assembly with a washer and nut retention bracket.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed retention nut is used for busbar connections, then the clamp load can be controlled for uniform thickness busbars, but the system cannot accommodate varying busbar thicknesses

Engineering Contradiction:

Improveclamp load controlVSAvoidaccommodation of varying thicknesses

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The retention nut is made floatable along the fastener length, allowing it to dynamically adjust its position to accommodate varying busbar thicknesses while maintaining proper clamp load through controlled movement constraints

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the retention nut is made floatable to accommodate varying thicknesses, then adaptability improves, but the complexity of the retention system increases

Engineering Contradiction:

Improveaccommodation of varying thicknessesVSAvoidretention system structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The retention system is divided into modular components: a floatable retention nut, a fastener, and a retention feature with controlled movement constraints, allowing independent optimization of each component while reducing overall system complexity

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If improper clamp load is applied to busbar joints, then assembly is simpler, but mechanical failure and high contact resistance occur

Engineering Contradiction:

Improveassembly simplicityVSAvoidjoint performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The floatable retention nut automatically adjusts its position along the fastener to self-regulate the clamp load, eliminating the need for complex adjustment mechanisms while ensuring proper mechanical and electrical contact

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10879659B2Variable connection retention system

Publication Date: 2020.12.29 KARMA AUTOMOTIVE LLC

AI summary

A variable connection retention system for a busbar. The retention system comprises of a dielectric overmold base. A main busbar is nested within overmold and engages a mating busbar. The overmold base includes a floating retention nut that displaces axially which engages the main busbar to the mating busbar when torque is applied.