Magnetic Encoder Slinger Surface Roughness for Bearing Sealing
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Solution Overview
Problem
Conventional rolling bearings with magnetic encoders in ABS systems face issues with magnet detachment and inadequate sealing performance, leading to increased costs and reduced lifespan due to surface roughness requirements and polishing processes.
Innovation Solution
A magnetic encoder with a slinger having an outer surface roughness of Ra: 0.3 to 3.0 μm for firm magnet bonding and an inner surface roughness of Ra: 0.3 μm or less for enhanced sealing, using a phenolic resin vulcanization adhesive and a multipolar magnet composed of magnetic powder and rubber, which prevents magnet detachment and improves sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer side surface of the slinger is roughened to enhance magnet bonding, then the magnet bonding force is improved, but the sealing performance deteriorates due to increased surface roughness
Solution Approach 1:
The slinger surface is treated with different roughness values for different regions: the outer side surface has Ra 0.3 to 3.0 μm for magnet bonding, while the inner side surface has Ra 0.03 to 0.3 μm for sealing contact. This local differentiation allows each surface to optimize its function without compromising the other.
Solution Approach 2:
The slinger surface is segmented into two distinct functional zones with different roughness characteristics. The outer side surface is roughened for magnet retention while the inner side surface is polished for sealing, creating functionally separated surface regions that address both requirements simultaneously.
2Reliability
If the inner side surface of the slinger is polished to enhance sealing performance, then the sealing performance is improved, but the magnet bonding force deteriorates due to reduced surface roughness
Solution Approach 1:
The slinger surface is treated with different roughness values for different regions: the outer side surface has Ra 0.3 to 3.0 μm for magnet bonding, while the inner side surface has Ra 0.03 to 0.3 μm for sealing contact. This local differentiation allows each surface to optimize its function without compromising the other.
Solution Approach 2:
The slinger surface is segmented into two distinct functional zones with different roughness characteristics. The outer side surface is roughened for magnet retention while the inner side surface is polished for sealing, creating functionally separated surface regions that address both requirements simultaneously.
3Reliability
If different surface roughness values are applied to the outer and inner side surfaces of the slinger, then both magnet bonding and sealing performance are improved, but manufacturing complexity increases due to additional polishing processes
Solution Approach 1:
The invention specifies precise surface roughness parameter ranges (Ra 0.3 to 3.0 μm for outer surface, Ra 0.03 to 0.3 μm for inner surface) that can be achieved through controlled polishing or blasting processes, making the differentiated surface treatment manufacturable while maintaining performance benefits.
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 ensures long-term reliability of the rolling bearing by firmly bonding the magnet and enhancing sealing performance, reducing material costs and production complexity while maintaining effective oil resistance.
Implementation Method 1
using a phenolic resin vulcanization adhesive
Implementation Method 2
a magnet bonded to the outer side surface through an adhesive
Implementation Method 3
a rubber multipolar magnet 109 mounted on an outer side surface 110 of the slinger 108. The slinger 108 and the multipolar magnet 109 are bonded and retained by an adhesive. A rotation sensor 112 provided outside the rolling bearing 101 detects a magnetic pole of the multipolar magnet 109
Implementation Method 4
a rubber multipolar magnet 109 mounted on an outer side surface 110 of the slinger 108
Implementation Method 5
an inner side surface opposed to a sealing member to seal the bearing, a film formed on the inner side surface, having surface roughness Ra: 0.3 μm or less, and being in sliding contact with the sealing member
Data Source
AI summary
The magnetic encoder (17) includes a slinger (18) fixed to a rotation-side raceway ring of a bearing and including an outer side surface (22) opposed to the side of a sensor to detect rotation speed of the rotation-side raceway ring and having a surface roughness Ra: 0.3 to 3.0 μm, and an inner side surface (23) opposed to the side of a sealing member (16) to seal the bearing; a multipolar magnet (19) bonded to the outer side surface (22) through an adhesive; and a film (25b) formed on the inner side surface (23), having a surface roughness Ra of 0.3 μm or less, and being in sliding contact with the sealing member (16).