Variable Diameter Raceway Bearing for Shaft Deflection
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Solution Overview
Problem
Conventional bearing arrangements, such as four-row ball bearings, require significant axial and radial installation space and have a low load rating, making them inefficient for applications with large deflections and high rotational speeds.
Innovation Solution
The use of cylindrical roller or needle bearings with raceways of variable diameters that transition from punctiform to linear contact as rotational speed increases, optimizing contact pressure and reducing installation space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a four-row ball bearing is used to support the shaft, then the bearing can handle the load, but the axial installation space requirement becomes large
Solution Approach 1:
The patent changes the contact geometry parameter from spherical (ball bearing) to cylindrical (roller bearing), which fundamentally alters the load distribution characteristics. This parameter change enables achieving the same load rating with significantly reduced axial space requirement, as cylindrical contact allows load distribution along the roller length rather than requiring multiple rows in the axial direction
Solution Approach 2:
The patent employs curved raceways with specific radii of curvature that match the roller geometry. The inner raceway has a radius R1 and the outer raceway has a radius R2, creating optimized contact conditions. This curvature design ensures proper stress distribution and enables the roller bearing to achieve high load ratings in a compact axial configuration
2Force
If the number of loadbearing rolling bodies is increased to handle higher loading, then the load rating improves, but the axial installation space increases
Solution Approach 1:
The patent changes from using multiple rows of ball bearings (increasing axial space) to using rollers with optimized cylindrical contact geometry. This parameter change in the rolling body shape allows achieving higher load ratings through increased roller count or larger roller dimensions without proportionally increasing axial space, as rollers provide more efficient load distribution per unit axial length
3Device complexity
If conventional cylindrical raceways are used, then the bearing structure is simple, but the contact pressures become asymmetric and excess dimensions are required
Solution Approach 1:
The patent applies different curvature radii to different parts of the raceway structure. The inner raceway has radius R1 and the outer raceway has radius R2, creating locally optimized contact conditions that adapt to the shaft's elastic line. This local quality variation ensures symmetric contact pressure distribution and allows compact bearing dimensions without increasing structural complexity
Solution Approach 2:
The patent designs the raceway curvatures to dynamically adapt to the shaft's deflection under load. The specific radius values R1 and R2 are chosen to match the expected elastic deformation of the shaft, ensuring that the contact conditions remain optimal across the operating range. This dynamic adaptation allows compact dimensions while maintaining symmetric contact pressures
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 stability and service life while minimizing axial and radial installation space, outperforming conventional designs by adapting to the elastic line of the unbalanced mass shaft, particularly in high-speed applications like internal combustion engines.
Implementation Method 1
one of the raceways having a diameter which is variable in the longitudinal direction of the shaft and is adapted to its elastic line
Data Source
AI summary
A bearing arrangement of a roller-mounted unbalanced mass shaft. The rollers are in punctiform contact with one of the raceways at a low shaft rotational speed, and in linear contact with both raceways at a high shaft rotational speed.