Shell-Type Needle Bearing Corrosion Coating for Universal Joints
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Solution Overview
Problem
Conventional cross-type universal joints using carbon steel shell-type needle bearings face corrosion issues under severe operating conditions, leading to seal lip wear and reduced durability, while using stainless steel increases costs and processing difficulties.
Innovation Solution
A shell-type needle bearing with a corrosion-resistant coating on the outer surface of the shell-type outer ring, specifically covering areas where seal lips come into contact, and a chemically treated film applied to the entire surface or selectively on high-corrosion areas, maintains durability and prevents foreign matter ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a carbon steel shell-type outer ring is used, then cost is reduced, but corrosion resistance deteriorates under severe operating conditions
Solution Approach 1:
The invention applies a corrosion-resistant coating to the outer surface of the shell-type outer ring, changing the surface properties without altering the base material. This allows the use of cost-effective carbon steel while providing the corrosion resistance typically associated with stainless steel, thus resolving the contradiction between cost and corrosion resistance.
2Reliability
If a corrosion-resistant coating is applied to the entire outer surface, then corrosion resistance is improved, but the outer diameter increases
Solution Approach 1:
The invention selectively applies corrosion-resistant coating only to specific areas of the shell-type outer ring where corrosion is most likely to occur and where seal lips make contact. This localized approach provides necessary corrosion protection while minimizing the increase in outer diameter, resolving the contradiction between corrosion resistance and dimensional constraints.
3Reliability
If the shell-type outer ring surface becomes rough due to corrosion, then seal lip wear increases, but using stainless steel to prevent corrosion increases cost and processing difficulty
Solution Approach 1:
The invention applies a corrosion-resistant coating to the shell-type outer ring surface, which maintains surface smoothness and prevents the roughening that occurs with corrosion. This protects the seal lips from excessive wear without requiring the use of difficult-to-process stainless steel, thus resolving the contradiction between seal lip durability and manufacturing ease.
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 effectively prevents corrosion and seal lip wear, maintaining the seal's integrity and durability under severe conditions without significantly increasing the outer diameter, thus lowering costs and ensuring long-term performance.
Implementation Method 1
at least part of a portion of an outer surface of the shell-type outer ring that is separated from the circular hole is covered by a corrosion resistant coating
Implementation Method 2
a chemically treated film applied to the entire surface or selectively on high-corrosion areas
Data Source
AI summary
Cross-type universal joint and a shell-type needle bearing that is used therein. The portions on the outer surface of the shell-type outer ring for which there is a possibility of coming in sliding contact with the tip end edges of at least two seal lips of a plurality of seal lips of a seal ring are selectively covered with a corrosion resistant coating. Preferably, the entire outer surface of the shell-type outer ring is covered by a chemically treated film having anti-corrosion properties.