Tapered Roller Surface Texture for Dilute Lubrication Bearings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tapered roller bearings experience surface damage, bearing rotation torque deterioration, and seizure issues under dilute lubrication and low lubricating oil viscosity due to increased friction at the sliding contact part between the large diameter-side end surface of the tapered roller and the flange portion, which are not adequately addressed by existing surface texture specifications.
Innovation Solution
A tapered roller bearing with surface roughness parameters of 0.02 to 0.17 μm in reduced peak height Rpk, 0.12 to 0.21 μm in core roughness depth Rk, and 0.07 to 0.43 μm in reduced valley depth Rvk, and an average recessed portion area of 5 μm2 or less, achieved through barrel processing, which enhances oil film formability and maintains lubrication without causing surface damage or torque deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface texture of the tapered roller is improved to enhance oil film formability at the rolling contact part, then surface damage is suppressed, but friction increases at the sliding contact part due to large unevenness, causing bearing rotation torque deterioration and seizure
Solution Approach 1:
The patent applies different surface roughness requirements to different parts of the tapered roller. The rolling surface (large diameter side) has Ra=0.02 to 0.17μm for oil film formation, while the sliding surface (small diameter side) has Ra=0.03 to 0.50μm for lubricant retention. This local differentiation resolves the contradiction by optimizing each surface for its specific function.
Solution Approach 2:
The patent changes the surface roughness parameters of different roller surfaces to resolve the contradiction. By controlling Ra values within specific ranges (0.02-0.17μm for rolling surface, 0.03-0.50μm for sliding surface), the patent achieves both oil film formability and lubricant retention, preventing both surface damage and torque deterioration.
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 specified surface texture improves oil film formability, preventing surface damage and torque deterioration, and enhances durability and seizure resistance, resulting in a long-life tapered roller bearing under dilute lubrication conditions.
Implementation Method 1
improving the oil film formability of the rolling contact part... effect of oil film formability improvement resulting from lubricating oil retainability improvement
Data Source
AI summary
In a tapered roller bearing, the surface roughness of at least a rolling surface and a large diameter-side end surface of a tapered roller is 0.02 to 0.17 μm in protruding mountain portion height Rpk, 0.12 to 0.21 μm in core portion level difference Rk, and 0.07 to 0.43 μm in protruding valley portion height Rvk and the average recessed portion area in the fine irregularities on the surface of the tapered roller is 5 μm2 or less. As a result, oil film formability can be improved under dilute lubrication and a decline in lubricating oil viscosity and surface damage at a rolling contact part and an increase in friction at a sliding contact part can be suppressed at the same time.