Angular Ball Bearing Raceway Geometry for Low Heat and Impact Resistance
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Solution Overview
Problem
Existing angular ball bearings experience high heat generation and damage from external impact loads due to high surface pressure at the contact points between rolling elements and raceway surfaces, leading to potential indentation and reduced machining accuracy.
Innovation Solution
The angular ball bearing design features an inner ring raceway groove with a groove curvature radius ratio of 54% to 58% and an outer ring raceway groove with a ratio of 51% to 58%, along with a cured surface layer on the inner ring raceway groove to manage surface pressure and enhance indentation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the groove curvature radius ratios of the outer ring and inner ring are set to be large, then heat generation is reduced, but surface pressure at the contact portion increases leading to indentation damage
Solution Approach 1:
The patent applies parameter changes by precisely controlling the groove curvature radius ratios within specific ranges (outer ring: 50.5%-53%, inner ring: 52.5%-60%) and setting their difference within 2.0 percentage points. This optimization balances the reduction of heat generation through larger curvature ratios while preventing excessive surface pressure that would cause indentation damage to the raceway surface.
Solution Approach 2:
The patent applies local quality by differentiating the groove curvature radius ratios between the outer ring and inner ring rather than using uniform values. The inner ring groove curvature radius ratio is set larger than the outer ring's, creating localized optimization at different contact points to simultaneously reduce heat generation and prevent indentation damage.
2Temperature
If the groove curvature radius ratio is increased to reduce heat generation, then thermal performance improves, but contact surface pressure increases reducing bearing reliability under impact load
Solution Approach 1:
The patent optimizes the groove curvature radius ratios within specific ranges (outer ring: 50.5%-53%, inner ring: 52.5%-60%) and controls their difference within 2.0 percentage points. This parameter optimization reduces heat generation through larger curvature ratios while preventing excessive surface pressure that would cause indentation damage, thereby maintaining reliability under impact loads.
3Loss of energy
If the groove curvature radius ratio is set to reduce heat generation, then thermal efficiency improves, but the bearing becomes more susceptible to indentation from external impact loads
Solution Approach 1:
The patent controls the groove curvature radius ratios within specific ranges (outer ring: 50.5%-53%, inner ring: 52.5%-60%) and limits their difference to 2.0 percentage points or less. This optimization reduces heat generation (improving energy efficiency) while preventing excessive surface pressure that would cause indentation damage, thereby maintaining strength against external impact loads.
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 design effectively reduces heat generation and damage from external impact loads, improving the angular ball bearing's performance, especially in high-speed machine tool spindle applications.
Implementation Method 1
at least the inner ring raceway groove has a maximum surface pressure of 4.7 GPa to 6.0 GPa when a sum of permanent deformation amounts of the ball and the inner ring raceway groove at a center of a contact portion between the ball and the inner ring raceway groove is 1/10,000 of the ball diameter
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
An angular ball bearing includes an inner ring that has an inner ring raceway groove having an arc-shaped cross section on the outer peripheral surface of the inner ring, an outer ring that has an outer ring raceway groove having an arc-shaped cross section on the inner peripheral surface of the outer ring, a plurality of balls provided rollably between the inner ring raceway groove and the outer ring raceway groove. A groove curvature radius ratio Ri of the inner ring raceway groove to a ball diameter is 54% to 58%, a groove curvature radius ratio Ro of the outer ring raceway groove to the ball diameter is 51% to 58%, and Ri - Ro ≥ 0 points. At least the inner ring raceway groove has a maximum surface pressure of 4.7 GPa to 6.0 GPa when a sum of permanent deformation amounts of the ball and the inner ring raceway groove at a center of a contact portion between the ball and the inner ring raceway groove is 1/10,000 of the ball diameter. Accordingly, it is possible to provide the angular ball bearing that can reduce the heat generation amount, and that can reduce the damage caused by the external impact load in the stationary state.