Multi-Row Ball Thrust Bearing for Low-Friction High-Speed Loads
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Solution Overview
Problem
Conventional thrust bearings, particularly cylindrical roller bearings, experience high frictional losses and contact issues due to the lack of a rolling condition along the roller's length, leading to sliding and increased friction at high rotational speeds, which complicates their use in transmissions.
Innovation Solution
A thrust bearing design featuring a cage with multiple rows of spherical rolling elements, such as balls, positioned between two races, allowing for relative rotation and load distribution, which reduces friction and heat generation by minimizing contact area from a line to a point, thereby enhancing efficiency and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If cylindrical roller bearings are used to increase load capacity through increased contact area, then load capacity is improved, but frictional losses increase due to lack of rolling condition along the roller's length
Solution Approach 1:
The patent segments the continuous cylindrical roller into multiple discrete spherical rolling elements arranged in rows. This segmentation allows each ball to maintain true rolling contact at its contact point while distributing the load across multiple elements, thereby reducing the sliding friction that occurs along the length of a continuous roller and reducing frictional losses.
Solution Approach 2:
The patent transitions from cylindrical rolling elements to spherical rolling elements. The spherical geometry ensures that each rolling element can achieve true rolling contact at its point of contact with the raceways, eliminating the sliding condition that occurs with cylindrical rollers. This curvature change allows the rolling elements to rotate on their own axes while maintaining rolling without sliding, thereby reducing frictional losses.
2Force
If cylindrical rollers are used to increase load capacity, then load capacity is improved, but the contact area at the ends causes rollers to drill into the bearing structure at high rotational speeds
Solution Approach 1:
The patent divides the continuous roller contact into discrete spherical rolling elements. This segmentation concentrates the contact force to specific point contacts rather than distributed line contacts, preventing the rollers from drilling into the bearing structure while still maintaining load capacity through the combined effect of multiple balls.
Solution Approach 2:
The spherical geometry of the rolling elements concentrates the contact force to a point rather than a line, as occurs with cylindrical rollers. This point contact prevents the drilling effect into the bearing structure that occurs with cylindrical rollers, especially at high rotational speeds, while the multiple rows of balls distribute the load to maintain load capacity.
3Force
If longer cylindrical rollers are used to increase load capacity, then load capacity is improved, but sliding increases at points other than one point due to lack of rolling condition
Solution Approach 1:
The patent segments the long roller into multiple smaller spherical rolling elements arranged in rows. Each spherical element maintains true rolling contact at its contact point, eliminating the sliding that occurs along the length of a long cylindrical roller. The segmentation allows each ball to independently maintain rolling without sliding conditions.
Solution Approach 2:
The spherical geometry of each rolling element ensures that rolling contact is maintained at the point of contact, regardless of the overall length of the bearing. Each ball can rotate on its own axis while maintaining rolling without sliding, eliminating the sliding friction that occurs with longer cylindrical rollers where the rolling condition cannot be maintained along the entire length.
4Force
If cylindrical roller bearings are used, then load capacity is improved, but device complexity increases due to cage requirements to align rollers into rows
Solution Approach 1:
The patent segments the bearing into multiple rows of spherical rolling elements, each row contained within the cage. This segmentation into discrete rows simplifies the cage structure compared to holding long cylindrical rollers, as the cage only needs to maintain spacing between spherical elements rather than long rollers. The segmented row structure reduces the complexity of the cage while maintaining load capacity.
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 multi-ball thrust bearing design reduces frictional losses, minimizes heat generation, and improves durability by distributing load effectively among multiple balls, reducing sensitivity to misalignment and maintaining efficient operation at high speeds.
Implementation Method 1
a plurality of rolling elements positioned between the first race and the second race... The rolling elements are configured to engage with interior surfaces of the face walls to allow relative rotation of the first race and the second race
Data Source
AI summary
A thrust bearing has an outer race and an inner race arranged for rotation relative to the outer race about an axis of rotation. Multiple rolling elements are positioned between the inner and outer races. A cage is positioned between the inner and outer races and configured to engage with the rolling elements to align the rolling elements into multiple rows, with the rows circumferentially spaced apart from one another.