Self-Aligning Radial Rolling Bearing for Shaft Deflection
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Solution Overview
Problem
Conventional ball bearings have a low load capacity and are prone to damage from misalignment and high contact stress due to angular shaft deflection, especially in high-temperature applications with significant radial and torsional loads.
Innovation Solution
A bearing device featuring an annular inner race with an axially convex surface and enlarged radial shoulders, along with a filleted lip, to maintain contact with the shaft and accommodate angular deflection, reducing contact stress and preventing misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional ball bearings are used, then low friction rotation is achieved, but load capacity is limited and misalignment damage occurs
Solution Approach 1:
The inner race is provided with a convex surface (crowned raceway) that has a curved profile along the raceway. This curvature allows the bearing elements to remain in contact with the raceway even when angular misalignment occurs, distributing the load more evenly and preventing edge loading that would cause damage. The curved surface essentially absorbs the misalignment through its geometric form.
Solution Approach 2:
The invention modifies the geometric parameters of the inner race by adding a convex surface with specific curvature radius. This parameter change transforms the rigid, flat raceway into a compliant, curved surface that can accommodate angular deflection. The curvature radius is specifically designed to match or exceed the bearing element diameter, ensuring proper contact geometry under misaligned conditions.
2Stability of the object's composition
If bearing elements are made of ceramic for high temperature stability, then dimensional stability improves, but fracture resistance worsens
Solution Approach 1:
The convex surface on the inner race acts as a cushioning element that prevents concentrated stress on the bearing elements. By distributing the load across a broader area and eliminating edge loading, the design preemptively protects brittle ceramic bearing elements from fracture while maintaining the dimensional stability benefits of ceramic materials at high temperatures.
3Stability of the object's composition
If the inner race is rigidly attached to the shaft, then rotational stability improves, but accommodation of angular shaft deflection worsens
Solution Approach 1:
The convex surface creates a point or line contact between the inner race and shaft rather than a broad surface contact. This geometric configuration allows the inner race to pivot slightly relative to the shaft, accommodating angular deflection while maintaining rotational stability through the bearing elements that transmit the rotational load.
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 withstands high radial and torsional loads by maintaining contact between the balls and races, preventing structural failure and extending the lifespan of the bearing device in high-temperature, high-pressure applications.
Implementation Method 1
The balls maintain separation between the races and reduce rotational friction between them
Implementation Method 2
The inner race further includes an axially convex surface along an innermost diameter of the inner race, the convex surface shaped to directly engage the exterior surface of the shaft when mounted thereto, such that the inner race remains in contact with the shaft while simultaneously accommodating radial deflection of the shaft
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A bearing device for supporting a shaft to rotate relative to an outer hub includes: an annular outer race mountable within an interior bore of the hub, the outer race including an inwardly facing radial groove sized to receive a rounded bearing element; and an annular inner race mountable to an outwardly curved exterior surface of the shaft. The inner race includes an outwardly facing radial groove sized to receive the bearing element, the respective radial grooves of the inner and outer races together forming an annular raceway to retain the bearing element when the bearing device is assembled. The inner race further includes an axially convex surface along an innermost diameter of the inner race, the convex surface shaped to directly engage the exterior surface of the shaft when mounted thereto, such that the inner race remains in contact with the shaft while accommodating radial deflection of the shaft.