Cylindrical Roller End Geometry to Prevent Edge Contact Noise
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Solution Overview
Problem
Cylindrical roller bearings experience edge contact issues under high axial loads or skew conditions, leading to temperature rise, seizing, and squeaking sounds, which existing solutions fail to completely prevent due to manufacturing variations and uneven grease distribution.
Innovation Solution
The design features chamfered portions and inclined surfaces on the roller end surfaces, with specific intersection angles ensuring continuous contact between the roller and flange surfaces, preventing edge contact and applying a constant axial pre-load to maintain roller alignment and reduce squeaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the roller end surface is formed with a curve having a relatively large radius of curvature (close to linear shape), then manufacturing is easier and the structure is simpler, but a discontinuous edge portion is generated at the intersection with the flange chamfer, causing edge contact under axial load or skew conditions
Solution Approach 1:
The roller end surface is formed with a curved surface having a specific radius of curvature that ensures continuous contact with the flange guide surface. The curvature is optimized to match the flange geometry, eliminating discontinuous edge portions while maintaining ease of manufacture through standardized curvature values.
2Reliability
If the roller end surface is formed with a sharp edge to prevent edge contact, then contact surface continuity is improved, but manufacturing precision requirements increase and the structure becomes more complex
Solution Approach 1:
The radius of curvature of the roller end surface is specifically controlled within a defined range to achieve continuous contact with the flange guide surface. By optimizing the curvature parameter, the patent eliminates edge contact without requiring excessive manufacturing precision or complex geometries.
3Object-affected harmful factors
If a constant axial pre-load is applied to maintain roller alignment and prevent squeaking, then noise reduction is achieved, but the device complexity increases due to additional pre-load mechanisms
Solution Approach 1:
The bearing structure itself generates the necessary pre-load effect through its geometric design. The curved roller end surfaces and flange guide surfaces are configured to maintain continuous contact and proper roller alignment through their inherent geometry, eliminating the need for separate pre-load mechanisms while still preventing squeaking sounds.
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
This configuration enhances axial resistance, prevents edge load-induced heat generation, and effectively silences the bearing by ensuring continuous surface contact and proper lubrication, even under high loads and skew conditions.
Implementation Method 1
end surfaces of the rollers are in sliding contact with the flange portion
Implementation Method 2
in a cylindrical roller bearing at the time of grease lubrication
Data Source
AI summary
A roller includes chamfered portions and roller inclined surfaces formed on both axial ends of a roller outer circumferential surface. When in a cross section taken along a plane including a rotation axis of the roller and a bearing central axis, an intersection angle between a tangent line of the roller inclined surface at the first position of the roller inclined surface corresponding to an end portion of a guide surface and a perpendicular line of the rotation axis is defined as α, an intersection angle between a tangent line of the roller inclined surface at the second position corresponding to a boundary between the chamfered portion and the roller inclined surface and a perpendicular line of the rotation axis is defined as β, and an intersection angle between the guide surface and a perpendicular line of the bearing central axis is defined as θ, α<θ<β is satisfied.