Rolling Bearing Plug Assembly with PEEK Protective Cap
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Solution Overview
Problem
Large-sized rolling bearings for submarine applications face corrosion issues due to sea water exposure, leading to reduced watertightness and plug maintenance difficulties, with existing materials like stainless steel being costly and difficult to machine, and nickel-based coatings wearing out quickly.
Innovation Solution
A rolling bearing assembly featuring a protective cap made of polyetheretherketone (PEEK) with a gasket ring and O-rings to prevent sea water ingress, combined with a stainless steel plug design that maintains smooth raceway surfaces and easy mounting/unmounting, ensuring corrosion resistance and watertightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the plug is made from bearing steel, then the machining of raceways is easy and high quality surface properties are achieved, but the plug corrodes when exposed to sea water
Solution Approach 1:
The plug assembly is divided into two distinct parts: a bearing steel plug body for easy machining and raceway formation, and a separate protective cap made from corrosion-resistant material (stainless steel or plastic). This segmentation allows each component to be optimized for its specific function - the plug body for manufacturing ease and the cap for corrosion protection.
Solution Approach 2:
The protective cap acts as an intermediary barrier between the bearing steel plug and the corrosive sea water environment. It protects the plug from direct exposure to corrosive elements while allowing the plug to maintain its manufacturing advantages.
2Reliability
If the plug is made from stainless steel, then corrosion resistance is improved, but machining of raceways becomes difficult and material piling up occurs
Solution Approach 1:
The solution separates the corrosion-resistant function (handled by the stainless steel or plastic protective cap) from the machining function (handled by the bearing steel plug body). This allows the plug body to be made from easily machinable bearing steel while the cap provides the necessary corrosion protection.
Solution Approach 2:
Different materials are used in different locations: bearing steel for the plug body where machining is required, and corrosion-resistant material (stainless steel or plastic) for the protective cap that contacts the sea water. Each location gets the material property it needs most.
3Reliability
If nickel-based coatings are applied to the plug, then corrosion resistance is improved, but the coating wears out rapidly after mounting and unmounting cycles
Solution Approach 1:
Instead of relying on a durable coating that eventually wears out, the solution uses a separate protective cap that can be easily replaced. The cap provides corrosion protection during the bearing's service life and can be removed and replaced during maintenance without damaging the underlying plug material.
Solution Approach 2:
The protective function is separated from the plug body and implemented as a distinct protective cap component. This allows the protection mechanism to be independent of the plug material and not subject to the same wear limitations as surface coatings.
4Reliability
If a pressure washer with O-ring seal is provided on the plug, then watertightness is improved, but the device complexity increases
Solution Approach 1:
The protective cap itself acts as a flexible or semi-flexible barrier that provides watertight protection. When made from plastic materials, it offers inherent sealing properties without requiring additional mechanical sealing components like pressure washers or O-rings.
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 maintains the bearing's watertightness and longevity by using PEEK for the protective cap and O-rings to seal the plug, ensuring reliable operation in seawater environments.
Implementation Method 1
The gasket ring is arranged between stainless steel bolts and the opening and is quenched between the protective cap and the surface of the first ring by a pressing force generated by the stainless steel bolts
Implementation Method 2
the plug has an essentially cylindrical outer surface provided with at least one circumferential groove for receiving an O-ring in order to further increase the liquid-tightness of the plug
Implementation Method 3
the protective cap is made of polyetheretherketone (PEEK), which is highly resistant to sea water corrosion
Data Source
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AI summary
The invention relates to a plug assembly for use in a rolling bearing comprising at least a first ring, at least one second ring, and at least one row of rolling elements (14) arranged between the rings, wherein the first ring is provided with an opening (18) for inserting rolling elements (14) into the space between the raceways or for taking rolling elements (14) out of the space between the raceways for assembly and maintenance. The plug assembly comprises a plug (20) configured to close said opening (18) when the bearing is operating, said plug (20) having an inner end face (20a) facing the rolling elements (14) and an outer end face (20b) opposite to the inner end face (20a). It is proposed that the bearing further comprises a protective cap (28) shielding the outer end face (20b) of the plug (20) from a corrosive environment of the bearing.