Insulated Bearing Overmolding to Prevent Layer Shift and Corrosion

Solution Overview

Problem

Bearings used in high-voltage environments, such as electric vehicles, suffer from electrical corrosion and movement of insulating layers, which compromise their insulation and longevity.

Innovation Solution

An insulated bearing design with grooves and knurling structures on the ring surfaces to embed the insulating layer, combined with a strategic gate placement for injection molding to prevent axial and circumferential movement, and optionally an outer metal ring for enhanced durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an insulating layer is overmolded on the outer ring or inner ring, then electrical insulation is achieved, but the insulating layer undergoes axial and/or circumferential movement after long-time operation

Engineering Contradiction:

Improveelectrical insulationVSAvoidinsulating layer position stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by creating material removal portions (grooves, knurling structures, or recesses) on the surface of the bearing ring before overmolding the insulating layer. These pre-formed structural features enable the insulating layer to be mechanically embedded and anchored, preventing axial and circumferential movement during operation while maintaining electrical insulation reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs composite materials by combining the metal bearing ring with an overmolded insulating layer material. The insulating layer is integrated into the metal substrate through mechanical embedding in material removal portions, creating a composite structure that provides both electrical insulation and mechanical stability, preventing layer separation or displacement under operational loads.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the insulating layer is overmolded on the bearing ring, then electrical insulation is provided, but the insulating layer is damaged due to high-speed and high-load operation

Engineering Contradiction:

Improveelectrical insulationVSAvoidinsulating layer durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies preliminary action by creating material removal portions (grooves, knurling structures, or recesses) on the surface of the bearing ring before overmolding the insulating layer. These pre-formed structural features enable the insulating layer to be mechanically embedded and anchored, preventing axial and circumferential movement during operation while maintaining electrical insulation reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs composite materials by combining the metal bearing ring with an overmolded insulating layer material. The insulating layer is integrated into the metal substrate through mechanical embedding in material removal portions, creating a composite structure that provides both electrical insulation and mechanical stability, preventing layer separation or displacement under operational loads.

Inventive Principle:

Principle #40Composite materials

3Reliability

If the weld seam of the insulating layer is formed in the main force-loading area, then the insulating layer provides complete coverage, but the weld seam reduces the strength in the force-loading area

Engineering Contradiction:

Improveinsulating layer coverageVSAvoidforce-loading area strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by strategically positioning the gate and controlling the overmolding process so that the weld seam forms in non-critical areas away from the main force-loading zones. The material removal portions are distributed to provide adequate embedding and anchoring of the insulating layer without concentrating weak points in high-stress regions, thereby maintaining both coverage and structural strength where needed.

Inventive Principle:

Principle #3Local quality

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 design provides effective electrical insulation and prevents movement of the insulating layer, improving the bearing's electrical performance and life.

Implementation Method 1

a gate used for an injection molding machine for overmolding the insulating layer is arranged so that the weld seam of the insulating layer after overmolding avoids the main force-loading area of the insulated ring and/or is formed in the insulating layer where the thickness of the insulating layer is maximum

Methodology Applied

Scientific EffectInjection molding:

Data Source

PatentUS20250237262A1Insulated bearing and method of manufacturing the same

Publication Date: 2025.07.24 AB SKF SKF PATENT DEPARTMENT

AI summary

An insulated bearing has an outer ring and/or inner ring as an insulated ring. The insulated ring has a body with a surface having a material removal portion. An insulating layer is overmolded on the body and molded into the material removal portion. A method of manufacturing the insulated bearing includes having a gate used for an injection molding machine for overmolding the insulating layer arranged so the weld seam of the insulating layer after overmolding avoids the main force-loading area of the insulated ring and/or is formed in the insulating layer where the thickness of the insulating layer is at a maximum. The insulated bearing solves the problem of electrical corrosion of bearings used in high-voltage environments. The insulated bearing achieves good electrical insulation and also prevents axial and/or circumferential movement of the insulating layer, improving the electrical performance and life of the insulating layer and the bearing.