Inner Ring Grinding Finish for Bidirectional Seal Torque Stability
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Solution Overview
Problem
The existing methods for grinding the outer circumferential surface of inner rings in rolling bearings result in deformation such as ridges and burrs, leading to a difference in sliding torque between forward and reverse rotation directions due to the directional nature of the deformation, affecting the sealing performance.
Innovation Solution
A method involving centerless grinding followed by a finishing process that forms grinding lines in irregular directions or improves surface roughness on the sliding contact surface, using techniques like polishing with an abrasive grain-containing brush or elastic grindstone, to eliminate directional surface roughness and reduce torque differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If centerless grinding is used to grind the sliding contact surface, then manufacturing efficiency is improved, but deformation such as ridges and burrs occurs on the surface
Solution Approach 1:
The grinding process is divided into two independent stages: rough centerless grinding for high efficiency material removal, and a separate finishing process for surface quality improvement. This segmentation allows each stage to optimize for its specific function without compromising the other.
Solution Approach 2:
The centerless grinding is performed as a preliminary roughing operation to rapidly remove material and achieve close dimensional accuracy, preparing the surface for the subsequent finishing process that will eliminate deformation and achieve final surface quality requirements.
2Ease of manufacture
If the sliding contact surface has directional deformation from grinding, then the grinding process is simple and fast, but the sliding torque difference between forward and reverse rotation increases
Solution Approach 1:
Instead of attempting to prevent deformation during the main grinding process, the invention applies a finishing process that deliberately acts in the opposite direction to remove the deformation caused by grinding, thereby eliminating the directional surface roughness that causes torque difference.
Solution Approach 2:
The finishing process changes the surface parameters by removing the directional deformation pattern created by grinding, transforming the surface from having uniform directional roughness to having randomized or reduced surface irregularities, thereby improving rotational characteristics consistency.
3Productivity
If a hard grindstone is used for efficient material removal, then productivity is improved, but surface deformation and burr formation increase
Solution Approach 1:
Different regions of the grinding system serve different functions: the hard grindstone is used for bulk material removal in the roughing stage, while a separate finishing process with different tooling characteristics is applied to the specific sliding contact surface region to achieve high surface quality and minimize deformation.
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 approach minimizes the difference in sliding torque of the seal lip with respect to the sliding contact surface, enhancing rotational characteristics and ensuring consistent performance under both forward and reverse rotations.
Implementation Method 1
abrasive grains in the grindstone come into contact with the outer circumferential surface of the inner ring. As the grindstone rotates relative to the inner ring, the abrasive grains move in a circumferential direction while being pressed against the outer circumferential surface of the inner ring. Thus, a metal present on the outer circumferential surface of the inner ring is removed using the abrasive grains.
Implementation Method 2
performing a finishing step in which a large number of grinding lines in irregular directions are formed on the sliding contact surface and/or processing for ameliorating a surface roughness of the sliding contact surface is performed. The finishing step can be performed by subjecting the sliding contact surface to polishing processing using an abrasive grain-containing brush, a non-woven fabric abrasive, or a polishing tape, polishing processing using an elastic grindstone.
Data Source
AI summary
A centerless grinding processing in which a sliding contact surface (10) is subjected to grinding by pressing a grindstone against the sliding contact surface (10) of an inner ring (3) while rotating the inner ring (3) relative to the grindstone in a prescribed direction, and then, in the centerless grinding process, a finishing step in which grinding lines in a direction intersecting grinding lines formed on the sliding contact surface (10) are formed on the sliding contact surface (10) and/or processing for improving the surface roughness of the sliding contact surface (10) is performed is performed.