Shell Type Roller Bearing Corrosion Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional shell type roller bearings face issues with sealing performance and corrosion resistance, particularly when exposed to exhaust gases, due to their use of case hardened steel and design limitations that lead to reduced service life and air leakage.
Innovation Solution
A shell type roller bearing made of austenitic stainless steel with flanges having a hardness of 300 to 450 HV, featuring a relief structure and a seal member made of fluororubber, ensuring improved corrosion resistance and sealing performance by reducing bulging and maintaining accurate press-fitting dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the width of the relief is increased, then the axial fitting dimension of the seal member is reduced, but the sealing performance decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the width of the relief (spacing between flanges) to optimize the balance between axial fitting dimension and sealing performance. By adjusting this geometric parameter, the seal member can achieve sufficient axial fitting dimension while maintaining effective sealing contact with the throttle valve stem.
2Length of stationary object
If the width of the relief is reduced to increase axial fitting dimension, then the inner peripheral surface tends to bulge during flange formation, but bearing clearance is reduced and service life decreases
Solution Approach 1:
The patent controls the width of the relief as a critical parameter to prevent excessive bulging of the inner peripheral surface during flange formation by bending. This parameter optimization ensures that the axial fitting dimension is sufficient while maintaining bearing clearance within acceptable limits for service life.
Solution Approach 2:
The shell outer ring is made of austenitic stainless steel material, which provides a favorable balance between formability (ease of bending without excessive bulging) and mechanical properties. This material selection helps maintain manufacturing precision while achieving the required axial fitting dimension.
3Ease of manufacture
If case hardened steel is used, then manufacturing process is established, but corrosion resistance is insufficient for exhaust gas environments
Solution Approach 1:
The patent employs austenitic stainless steel material for the shell outer ring, which provides excellent corrosion resistance against exhaust gases while maintaining manufacturability. This material substitution resolves the contradiction between ease of manufacture and corrosion resistance by selecting a material that inherently possesses both required properties.
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 solution enhances sealing performance and corrosion resistance, extending the service life of the bearings in high-temperature and corrosive environments while preventing air leakage and ensuring correct dimensional accuracy.
Implementation Method 1
corrosion resistance is ensured by the austenitic stainless steel material
Implementation Method 2
Since the hardness of the flange is set in the range of 300 to 450 HV, the inner peripheral surface of the shell outer ring is less likely to bulge when forming the flange by bending
Data Source
AI summary
A shell type roller bearing includes a shell outer ring that includes a cylindrical portion (12) and a flange (13) extending radially inward from one axial end of the cylindrical portion and that is made of an austenitic stainless steel material. One axial end portion of an inner peripheral surface (16) of the cylindrical portion (12) is a tilted surface (16b), the inner diameter of the tilted surface (16b) is larger than the inner diameter of an axial middle region of the inner peripheral surface (16), and the hardness of the flange (13) is in the range of 300 to 450 HV.