Rolling Bearing Grounding Member With Soft Contact for Electrolytic Corrosion

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Solution Overview

Problem

Existing electrolytic corrosion prevention methods for rolling bearings in electric vehicles generate abrasion powder that contaminates lubricating oil, damage mating members, and require additional processing or space, limiting their versatility.

Innovation Solution

An electrolytic corrosion prevention member featuring a spring plate with an annular portion and radial elastic portions made of conductive material, combined with a soft conductive member that abuts against the rotating ring, effectively prevents electrolytic corrosion without generating significant abrasion powder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conductive member is used to prevent electrolytic corrosion, then electrolytic corrosion is prevented, but abrasion powder is generated that contaminates lubricating oil and damages mating members

Engineering Contradiction:
Improveelectrolytic corrosion preventionVSAvoidabrasion powder generation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs a soft conductive member made of electrically conductive rubber that can be easily replaced. This member is designed to be consumable, allowing it to be replaced periodically without affecting the bearing itself. The soft material generates minimal abrasion powder compared to metal conductive members, and when worn out, the entire soft conductive member can be discarded and replaced as a unit, protecting the expensive bearing from damage.

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

Solution Approach 2:

The patent changes the material parameters of the conductive member from hard metal to soft electrically conductive rubber. This parameter change reduces the hardness and abrasiveness of the conductive member, thereby minimizing abrasion powder generation. The soft material deforms elastically under contact pressure, reducing mechanical wear on both the conductive member and the bearing raceway, while maintaining sufficient electrical conductivity to prevent electrolytic corrosion.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If metal conductive members are used, then electrolytic corrosion is prevented, but metal powder is generated through sliding contact

Engineering Contradiction:
Improveelectrolytic corrosion preventionVSAvoidmetal powder generation
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent uses a composite material structure where a soft conductive rubber layer is applied on a support structure. The electrically conductive rubber contains conductive fillers (such as carbon black or metal particles) dispersed in a rubber matrix. This composite structure provides both the electrical conductivity needed to prevent electrolytic corrosion and the softness required to minimize metal powder generation through sliding contact, combining the benefits of both metal and non-metal materials.

Inventive Principle:
Principle #40Composite materials

3Reliability

If existing corrosion prevention methods are implemented, then electrolytic corrosion is prevented, but additional processing or space is required

Engineering Contradiction:
Improveelectrolytic corrosion preventionVSAvoidadditional processing and space requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the corrosion prevention function with the bearing assembly by integrating the soft conductive member directly into the bearing unit structure. The conductive member is positioned between the bearing and the motor housing, combining electrical conductivity, mechanical support, and corrosion prevention in a single integrated component arrangement. This eliminates the need for separate corrosion prevention devices and reduces overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The soft conductive member serves multiple functions simultaneously: it provides electrical conductivity to prevent electrolytic corrosion, acts as a mechanical buffer to reduce vibration and shock, and serves as a wear surface that protects the bearing raceway. This multi-functionality reduces the need for additional components and processing steps, simplifying the overall bearing unit design.

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

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 solution effectively prevents electrolytic corrosion of rolling bearings, minimizes damage to mating members, and can be used with existing bearings without additional processing or increased space, enhancing versatility.

Implementation Method 1

a spring plate (10A) including an annular portion (11A) and a plurality of elastic portions (13A) that extend continuously from the annular portion in a radial shape

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

being formed of a thin plate of a conductive material; and a soft conductive member mounted on a surface of the elastic portion

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4542066A1Electrolytic corrosion prevention member for rolling bearing and electrolytic corrosion prevention rolling bearing unit
Publication Date: 2025.04.23 NSK WARNER
  • EP4542066A1 patent drawingFigure 1A~1C
  • EP4542066A1 patent drawingFigure 2~3
  • EP4542066A1 patent drawingFigure 4A~4B

AI summary

An electrolytic corrosion prevention member for a rolling bearing, the electrolytic corrosion prevention member being mounted on a rolling bearing unit including the rolling bearing in which one bearing ring is a fixed ring and the other bearing ring is a rotating ring in order to prevent electrolytic corrosion of the rolling bearing, the electrolytic corrosion prevention member includes: a spring plate including an annular portion and a plurality of elastic portions that extend continuously from the annular portion in a radial shape and being formed of a thin plate of a conductive material; and a soft conductive member mounted on a surface of the elastic portion that faces the rotating ring. The soft conductive member is capable of abutting against a side surface of the rotating ring.