Insulated Bearing Bushing Structure to Prevent Lining Separation

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Solution Overview

Problem

Existing roller bearings in electric motors and electrical machines face issues with electrical discharges and vibrations due to potential differences between the shaft and housing, leading to component damage and requiring costly hybrid solutions or insulation sleeves that can separate during operation.

Innovation Solution

A bearing device with a single-piece bushing and integrated insulation lining, featuring flanges that extend beyond the ring surfaces, providing mechanical strength and secure integration to prevent separation, made from materials like steel and synthetic or elastomer for temperature resistance and insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an insulation sleeve with bushing and lining is used to prevent electrical discharge, then electrical insulation is improved, but the insulation lining may separate from the bushing during operation

Engineering Contradiction:

Improveelectrical insulationVSAvoidintegration of insulation lining and bushing

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The bushing is divided into multiple axial portions with flanges at different positions, creating distinct functional zones that work together to secure the insulation lining through overmolding on multiple surfaces

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The insulation lining is nested within the bushing structure, with the lining overmolded onto the bushing's exterior surface and flange inner faces, creating a integrated nested assembly that prevents separation

Inventive Principle:

Principle #7Nested doll (Nesting)

2Device complexity

If the insulation lining is over-molded on the bushing without additional elements, then the device complexity is reduced, but the mechanical strength and integration may be insufficient

Engineering Contradiction:

Improvenumber of additional elementsVSAvoidmechanical strength of insulation integration

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The bushing flanges extend axially beyond the bearing rings, adding an axial dimension to the integration scheme. The insulation lining is overmolded not only on the radial surface but also on the axial faces of the flanges, creating multi-surface integration that enhances mechanical strength without adding separate components

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Strength

If the bushing extends radially beyond the bearing ring surfaces, then the mechanical strength is improved, but the device complexity increases

Engineering Contradiction:

Improvemechanical strength of bushingVSAvoidbushing structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The bushing flanges serve multiple functions simultaneously: they provide structural reinforcement for mechanical strength, create additional overmolding surfaces for insulation integration, and extend axially to distribute loads. This multi-functionality reduces the need for separate components despite the extended geometry

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 enhances mechanical strength and reliability by preventing insulation displacement and shearing stresses, ensuring effective electrical insulation and temperature stability, thus reducing component damage and vibrations.

Implementation Method 1

The insulation lining is made of electrically insulating material

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

The risk of relative displacements between the insulation lining and the bushing in the axial direction is avoided in particular during variations of temperatures

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20260022738A1Bearing device with integrated electrical insulation, in particular for a motor or an electrical machine, and associated production method

Publication Date: 2026.01.22 AB SKF SKF PATENT DEPARTMENT

AI summary

A bearing device includes a ring having a cylindrical surface and first and second axially spaced end surfaces, a bushing, and an electrically insulating insert overmolded between and connecting the bushing and the cylindrical surface of the second ring. The bushing includes an cylindrical portion and a first annular flange extending radially from a first axial end of the cylindrical portion and a second annular flange extending radially from a second axial end of the cylindrical portion, and a portion of the ring is located axially between the first and second annular flanges. A minimum axial distance between the first annular flange and the second annular flange is greater than the maximum axial width of the ring, and the electrically insulating insert is overmolded onto the cylindrical portion and onto the first annular flange and onto the second annular flange and onto the ring.