Electrically Insulated Bearing Assembly With Elastic Overmolded Insert

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Solution Overview

Problem

Existing rolling bearings in electric motors and machines face issues with electrical potential differences causing current flow, leading to component damage and vibrations, and hybrid bearings are expensive and prone to relative uncoupling.

Innovation Solution

A bearing device with an insulating sleeve and elastically deformable member integrated between the second ring and bushing, providing electrical insulation and a rigid connection, which is economical and easy to manufacture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rolling elements are replaced with ceramic to prevent electrical damage, then reliability is improved, but device complexity and cost increase

Engineering Contradiction:

Improveprotection against electrical damageVSAvoidhybrid bearing structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

An insulating insert is introduced as an intermediary element between the outer ring and the rolling elements. This insert is made of electrically insulating material and is overmolded onto the outer ring, creating an electrical barrier that protects the rolling elements from electrical damage without requiring a complete hybrid bearing redesign

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating insert is nested within the bearing structure, specifically positioned between the outer ring and the rolling elements. The insert is overmolded onto the outer ring, creating a layered configuration where the insulation layer is integrated into the existing bearing components rather than replacing entire components

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of manufacture

If an insulating insert is overmolded onto the outer ring, then manufacturing ease is improved, but relative uncoupling occurs during operation

Engineering Contradiction:

Improveovermolding processVSAvoidconnection between insulating insert and bushing

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The connection system is segmented into multiple functional zones: the overmolded insulating insert provides electrical insulation, while the elastically deformable member provides mechanical connection and positioning. This segmentation allows each component to perform its specific function optimally without compromising the other

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The elastically deformable member changes its physical parameters (shape and size) under compression, transitioning from a larger free-state configuration to a compressed state within the bearing. This parameter change enables the member to provide continuous elastic force that maintains stable connection between the insulating insert and the bearing components

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a simple insulating insert is used without additional elements, then device complexity is reduced, but connection stability deteriorates

Engineering Contradiction:

Improvenumber of additional elementsVSAvoidconnection stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The elastically deformable member provides self-adjusting connection through its inherent elasticity. As the bearing operates and experiences dimensional changes due to temperature or load, the elastic member automatically adjusts its compression level to maintain stable connection, eliminating the need for complex adjustment mechanisms or additional fastening elements

Inventive Principle:

Principle #25Self-service

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 electrical damage and vibrations while ensuring a stable connection, maintaining insulation integrity under temperature variations and reducing manufacturing complexity.

Implementation Method 1

at least one elastically deformable member which is located radially between the second ring and the bushing... the elastic member is radially in contact at least with one of the surface of the second ring and the surface of the bushing by being compressed in the radial direction

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20250341232A1Bearing device with integrated electrical insulation, notably for an electric motor or machine, and associated manufacturing methods

Publication Date: 2025.11.06 AB SKF SKF PATENT DEPARTMENT

AI summary

A bearing device includes a bearing having first and second mutually rotatable rings, the second ring having a first cylindrical surface and a second cylindrical surface radially spaced from the first cylindrical surface, and a bushing having an axial length and a first cylindrical surface and a second cylindrical surface radially spaced from the first cylindrical surface of the bushing. An elastically deformable member is located radially between the second ring and the bushing, and an electrically insulating insert is overmolded between and connects the first cylindrical surface of the bushing and the second cylindrical surface of the second ring and contacts the elastically deformable member. The elastically deformable member radially contacts the second ring and/or the bushing and is radially compressed relative to a free state of the elastically deformable member.