Raceway Ring Surface Inspection for Rotation Torque Symmetry
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Solution Overview
Problem
The grinding process for raceway ring members in rolling bearings and hub unit bearings often results in deformations such as bumps and burrs, leading to uneven sliding torque when the seal lip comes into contact with the sliding surface, causing differences in rotation torque between forward and reverse rotation directions.
Innovation Solution
An inspecting method that photographs the sliding surface, detects machining marks in irregular directions using a camera and imaging process, and estimates the rotation characteristics to ensure the surface is prepared to minimize torque differences before assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the outer circumferential surface of the inner ring is subjected to grinding using a grindstone, then the sliding surface is prepared to minimize sliding torque, but deformations such as bumps and burrs occur on both sides of the portion through which abrasive grains pass
Solution Approach 1:
The patent converts the harmful deformations (bumps and burrs) created by grinding into beneficial features by intentionally creating controlled surface irregularities through a subsequent processing step. This transforms the defect into a functional characteristic that helps minimize sliding torque differences between forward and reverse rotation directions.
Solution Approach 2:
The patent changes the surface parameters by introducing controlled irregularities with specific height and distribution characteristics. By adjusting parameters such as the number, height, and spatial distribution of surface irregularities, the patent optimizes the sliding characteristics to reduce torque differences while avoiding the harmful effects of uncontrolled grinding deformations.
2Ease of manufacture
If a rotating grindstone is pressed against the outer circumferential surface of the inner ring, then metal is removed to create a sliding surface, but a difference in rotation torque between forward and reverse rotation directions occurs
Solution Approach 1:
The patent converts the harmful effect of directional grinding marks that cause torque inconsistency into a beneficial state by creating controlled surface irregularities. These intentional irregularities compensate for the directional bias introduced by grinding, thereby reducing the difference between forward and reverse rotation torques and improving reliability.
Solution Approach 2:
The patent applies a preliminary processing step after grinding to create controlled surface irregularities before the final assembly. This preliminary action prepares the surface in advance to compensate for the effects of grinding, ensuring that the sliding surface will provide consistent rotation torque in both directions during operation.
3Productivity
If the inner ring is rotated in a predetermined direction during grinding, then the sliding surface is formed, but the sliding torque differs between forward and reverse rotation directions
Solution Approach 1:
The patent changes the surface parameters by introducing controlled irregularities with specific height, distribution, and orientation characteristics. By carefully controlling these parameters, the patent maintains the efficiency of unidirectional grinding while compensating for the resulting torque asymmetry, achieving both high productivity and reliable symmetric sliding torque characteristics.
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 method allows for the estimation of rotation torque differences before assembly, reducing the need for rework and improving the assembly efficiency by ensuring the surface is adequately prepared with machining marks, thus minimizing torque discrepancies.
Implementation Method 1
obtaining an original image by photographing at least a part of the sliding surface with which a distal end portion of a seal lip comes into sliding contact over the entire circumference using a camera
Implementation Method 2
performing an imaging process on the original image and detecting a plurality of machining marks on the sliding surface
Implementation Method 3
abrasive grains in the grindstone come into contact with the outer circumferential surface of the inner ring along with relative rotation of the grindstone with respect to the inner ring. Movement in a circumferential direction is performed while the abrasive grains are pressed against the outer circumferential surface of the inner ring
Data Source
AI summary
A photographing step of obtaining an original image by photographing a part or all of a sliding surface using a camera is performed and then an imaging process of detecting machining marks on the original image is performed; a detecting step of obtaining a detection image is performed; and an evaluating step of estimating a difference of a rotation torque of the raceway ring member with respect to another raceway ring member on the basis of the detection image in a direction of relative rotation between the raceway ring member and the other raceway ring member when a rolling bearing is constituted by combining a raceway ring member with the other raceway ring member is performed.