Bearing Closure Element Diverts Current to Shaft
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Solution Overview
Problem
High-speed spindle bearings in electric motors, generators, and machines experience damage and failure due to electrical currents passing through rolling elements, leading to fluting, noise, premature failure, and significant costs from machine downtime and repair.
Innovation Solution
A bearing design incorporating a closure element, such as a seal or shield, secured between the outer and inner rings to divert electrical currents from the rolling elements to the shaft, utilizing a current conducting layer to establish a path from the outer ring to the inner ring, thereby bypassing the rolling elements and minimizing contact friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic rolling elements are used for current insulation, then electrical current resistance is improved, but cost increases and complete protection is not achieved
Solution Approach 1:
The invention extracts the current conduction function from the rolling elements and transfers it to the closure element. The closure element is positioned to contact both the outer and inner rings, creating a dedicated current path that bypasses the rolling elements entirely, thus protecting them from current damage without requiring expensive ceramic materials.
Solution Approach 2:
The closure element acts as an intermediary current conductor between the outer ring and inner ring. It provides a controlled path for electrical currents to flow through the bearing assembly without passing through the rolling elements, thereby protecting the rolling elements from current-induced damage.
2Reliability
If ceramic coated outer rings are used for current insulation, then current resistance is improved, but manufacturing cost increases and coating wear reduces effectiveness
Solution Approach 1:
The invention removes the current insulation function from the outer ring coating and relocates it to the closure element. This eliminates the need for expensive ceramic coatings on the outer ring while maintaining current protection through the closure element's contact path between the outer and inner rings.
3Reliability
If electrical conductive grease is used for current conduction, then current conduction is improved, but bearing lubrication performance deteriorates
Solution Approach 1:
The closure element serves as a solid intermediary for current conduction between the outer and inner rings, replacing the need for conductive grease. This solid-state current path maintains bearing lubrication performance while providing reliable current conduction without introducing contaminants.
4Reliability
If dissipative brushes are used in shaft seal for current grounding, then current grounding is improved, but device complexity and space requirements increase
Solution Approach 1:
The invention merges the current conduction function with the bearing closure element itself, eliminating the need for separate dissipative brushes or independent shaft seals. The closure element is integrated into the bearing assembly and provides both mechanical closure and electrical current path functions in a single component.
5Reliability
If slip rings are used for current conduction, then current conduction is improved, but wear increases and reliability decreases
Solution Approach 1:
The closure element acts as a wear-free intermediary for current conduction between the outer and inner rings. Unlike slip rings that require sliding contact and suffer from wear, the closure element provides a controlled current path without relative motion, eliminating wear while maintaining current conduction capability.
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
Effectively prevents electrical current damage to the rolling elements, reduces machine noise and downtime, and maintains lubrication while minimizing wear and contamination, enhancing the reliability and efficiency of high-speed applications.
Implementation Method 1
a current conducting layer, to establish a path from the outer ring to the inner ring
Data Source
AI summary
At least one closure element is arranged between an outer ring and an inner ring of a bearing. The closure element aids in ensuring electric current is kept away from the rolling elements by diverting electric current from the outer ring to the inner ring of the bearing and onto a shaft of an associated machine. The closure element can take the form of either a seal or a shield. The closure element is arranged in the outer ring and contacts at least one of the notches of the inner ring. Preferably, more than one closure element is used.