Insulating Ring for Electric Motor Bearing Protection
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Solution Overview
Problem
Rolling bearings in electric motors are prone to premature degradation due to electrical leakage currents, which cause electric arcs and overheating, and existing insulation methods are inadequate for high-frequency currents and complicate mounting.
Innovation Solution
A titanium or titanium alloy ring with a dielectric coating is interposed between the shaft and the bearing, providing both electrical and thermal insulation, effectively shielding the bearing from leakage currents and reducing heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic dielectric layer is added to insulate the bearing, then protection against leakage currents is improved, but ease of mounting deteriorates
Solution Approach 1:
The insulation function is separated into a distinct ring component that can be independently manufactured and optimized. This segmentation allows the bearing to remain in its standard, easily mountable form while the separate ring provides the necessary electrical insulation, thus maintaining ease of mounting while achieving protection.
Solution Approach 2:
The insulating ring acts as an intermediary component that can be easily fitted between the shaft and the bearing. This mediator provides the required electrical insulation without requiring modification of either the shaft or the bearing, preserving the simplicity of the mounting process.
2Reliability
If a ring with dielectric coating is used for insulation, then protection against both low and high frequency currents is improved, but device complexity increases
Solution Approach 1:
The insulating ring is designed to perform multiple functions simultaneously: it provides electrical insulation against both low and high frequency leakage currents, and it can be integrated into the existing bearing assembly without requiring additional components or complex installation procedures. This multi-functionality reduces the overall device complexity despite adding a protective component.
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 protects the bearing from both low and high-frequency leakage currents, prolongs its service life by preventing overheating, and simplifies mounting without altering the standard bearing design.
Implementation Method 1
a ring which is interposed between the shaft and the rolling bearing and which is insulated from the shaft by a dielectric coating
Implementation Method 2
titanium having a coefficient of thermal conductivity at least three times lower than that of steel... which further contributes to reducing the transmission heat from the shaft to the bearing
Data Source
Figure 1~2
AI summary
The device has a ring (B) arranged between a shaft (A) of an electric motor and a rolling bearing. The ring is electrically isolated from metallic deflectors (17) arranged in contact with the shaft by a dielectric coating (19). The dielectric coating covers an inner surface (20) and an end surface (21) of the ring. The end surface of the ring is abutted against a shoulder (22) of the shaft. The dielectric coating is made of ceramics. The ring is blocked in position on the shaft by press-fit. An independent claim is also included for a rolling bearing mounted on a shaft of an electric motor, comprising a protecting device.