High Precision Stainless Steel Deep Groove Ball Bearing 61802 for Engineering Machine

Model NO.
ball bearing 61802
Origin
China
HS Code
84821090
Reference Price
$ 0.81 - 0.90
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Product Description




Structure and Parts of Bearings

Deep Groove Ball Bearings
Structure of deep groove ball bearing basically include inner ring, outer ring, roller elements and cages. Seal rigns and dust shields are designed to prevent foreign matters like dust or oils from entering. The main purpose of lubricant used is to achieve the reduction of friction and damage of roller elements.

Cage
In daily operations, cage will be subjected not only to mechanical action from friction, tension and inertial force, but to chemical reaction from lubricants, additives, solvents or coolants. Therefore, design and materials of cage are very inportant for its performance and the reliability of bearing in usage.
Flate/FUDA offers the following kinds of cage for deep groove ball bearings:

Rivet type cage

It is a kind of cage made by strip steels in high precision, turned into spherical pockets through profiling and fixed with rivets, usually applied to small and medium deep groove ball bearings.
Crank jaw type cage

It is a kind of cage made by strip steels in high precision, turned into spherical pockets through profiling and caulked by crank jaw and two pairs of retainers, usually applied to miniature deep groove ball bearings.
Cage with synthetic resin material

Synthetic resin cage is made by combination of several materials, including nylon PA66 with glass fiber. It has self-lubricating and low noise features, usually used for bearings with extremely low noise.

Materials of Bearings
Materials for bearing rings and parts largely determine the bearing's performance and life. FLATE/FUDA puts more efforts to select materials for bearing rings and part suppliers in a rigorous manner.
Materials and components of bearing rings for FLATE/FUDA bearings are provided by the world's top suppliers special for serving bearign manufacturers, fundamentally solvign the issue that our bearings lag behind imported bearings in terms of materialsfor a long time.
FLATE boasts a set of strict and polished incoming goods inspection system. Before being put into storage, every batch of steels and parts is under systemic inspection, including analysis of material composition, metallographice analysis, accuracy check, assembly test, etc.
Materials for Bearing Ring and Roller Body
Bearing ring and roller body are mainly made of high C-Cr bearing steel. Listed below are compositions of material for bearing ring and roller body.

Steel Code 		Chemical composition%
Gcr15
SAE52100
DIN 100 Cr6
JIS SUJ2 		C Si Mn P S Cr Mo Cu Ni
0.95-1.05 0.15-0.35 0.25-0.45 <0.025 <0.025 1.40-1.65 - <0.25 <0.30

Material for bearing ring and roller body mainly consists of high C-Cr bearing steel.
Material of cages
Material of cages need good wear resistance, stable size and metal strength. Therefore, operation environment should be mainly considered in selection of material of cages.
Drawing steel sheet cage
These light cages hold a high strength with reduced friction and wear in an effective way after surface treatment. The following table covers compositions of material for cold-rolled steel sheet.

Steel code 		Chemical Composition%
JISG 3141
SPCC 		C Si Mn P S Ni Cr
<0.12 - <0.5 <0.04 <0.045 - -

Brass cage
Cut brass cage is adopted in small and medium bearings. However, brass cage is not suitable for compressors with ammonia cooling due to potential seasonal cracking of brass. It is recommended to replace it with iron cage.
Nylon cage
According to the type and usage of bearings, nylon cages are widely adopted, but they are inappropriate for environments where the temperature is above 120ºC or below 40 ºC. Most of cast molding cages adopt nylon PA66 material, with or without glass fiber reinforcement whose advantage is a good combination of strength and elasticity.
Materials for dust shield and seal ring
Material for dust shield
FLATE/FUDA bearings use cold-rolled tin plate as the standard mateiral for dust shields, but also use stainless steel of AISI-300 specification at times.
Material for seal ring
Seal rings are mainly made of NBR. For high temperature, fluororubbers and silicon rubbers are widely used as well.

Type 		ASTM D1418 Name Temperature Range Hardness
(Shore A) 		Features Restriction
Nitrile butaduene rubber NBR -40ºC~120ºC 40-90 Low compression
High ductility
High corrosion resistance
superior oil resistance 		Unsuitable for high temperature conditions;
No exposure to the sun and corrosion of chemicals
Silicon rubber MQ/PMQ
VMQ/PVMP 		-70ºC~200ºC 25-80 High temperature resistance
Desiccation resistance
Sunshine resistance
aging resistance to ozone 		Poor surface abrasion performance and crack resistance, higher wear resistance
Hydrogenated
(nitrile-butadiene rubber) 		HNBR/NEM -35ºC~65ºC 50-90 Heat resistance
High ductility
Chemical resistance 		Unsuitable for high temperature conditions and shall avoid exposure to the sun and corrosion of chemicals
Fluororubber FKM/FPM -28ºC~200ºC 50-95 High temperature resistance
Significant chemical resistance
corrosion resistance to petroleum products 		It is not suitable for working conditions of low temperature.
ACM rubber ACM Rubber -18ºC~175ºC 40-90 Stronger resistance to hot oil
Sunlight and ozone
Higher crack resistance 		poor waterproof performance;
unsuitable for working condition of ultra-low temperature
Warning:flurorubber is safe and harmless under normal working condition of below 200ºC, but it will give off smoke if the temperature exceeds the ultimate temperature of 300ºC that is equivalent to flame for cutting steel tubes. Inhalation of the smoke is harmful to human bodies including eyes. In addition, the smoke should be avoided to contact skin.

Lubrication of Bearings

Grease lubrication 		Lipid lubricants are much easier to use than oil lubricants. Due to its ciscosity,grease is more durable and only needs simple sealing equipment to contain. Grease is hard to be changed, beacause the usual approach of it is to press grease into device to make fresh grease squeeze used grease out. General speaking, grease with low viscosity primary oil is more suitable for high speed operations at low temperature, while grease with high viscosity primary oil is suitable for heavy load.
Oil lubrication Oil lubrication is more suitbale for applications under conditions of high speed and high temperature, effectively taking the heat generated in operation of bearings away. Viscosity of oil determines the effects of oil lubrication. Low viscosity will lead to inadequate formation of oil film, while high viscosity will increase viscous drag and temperature. In general, the higher rotational speed is the lower viscosity of lubricant oil will be; the larger load is, the higher viscosity of lubricant oil will be.
Primary oil In grease, primary oil accounts for 75-96%. In mass fraction, the performance of grease mainly relies on the nature of primary oil. Particularly when it is with cold flow property and at high temperature, its service life is bound up with primary oil. Grease with low viscosity primary oil is usually applicable to low temperature and low load, while lubrication grease with high viscosity primary oil is applied to high temperature and high load. Primary oil used in grease includes mineral oil and synthetic oil. The commonly used synthetic primary oils contain lipid oil, sythetic hydrocarbon oil, perfluoropolyether, silicon oil and PPO, etc.
Thickener Thickener generally accounts for 4~20% in mass fraction. Its functions are to suspend primaty oil, reduce the flow of primaty oil, and increase adhesion of oil to friction surface. Thickener has two categories: metallic soap base and non-metallic soap base. Critical operating temperature, mechanical stability, water resistance and other properties of grease are determined by thickener, for example, sodium soap base can react with water to form a kind of latex, which can not be applied to running bearing in the atomsphere of high temperature.
Additive In grease, primary oil accounts for 0.5~10%. In mass fraction, which is used for the improvement of operating performance and life of grease. Accordign to the classification by function, it can be divided into thickener(strong adhesion), antioxidant, extreme-pressure additive, corrosion inhibitor,etc.

 

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