PowerPointPrsentation

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Lubrication Of Plain Bearings
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Plain Bearings are theoldest Types of Bearings
l At first shafts and bushes were made of
wood. Later iron and bronze were used.
l The lubrication was done with olive oil or
with a mixture of oil and lime.
Roman building crane with pulley block and human
power drive. (500 B.C.)
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Plain Bearings in modern machines
Plain bearings are indispensable in nowadays
technology.
A car engine contains more than 90 plain
bearings.
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Friction in Plain Bearings
l rest position of the shaft, metal / metal
contact (no lubrication between shaft and
bearing)
l with increasing speed an oil film between
bearing and shaft is developed.
l it finally results in a total separation of
shaft and bush. (The friction increases
with higher speed (rpm) in this sector of
hydrodynamic friction)
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Plain Bearing
If possible, the bushes, made out of a material
with good sliding abilities, will be put into a
housing of cast iron with good mechanical
stability. The bushes remain replaceable.
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Comparison of Plainand Roller Bearings
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Determining Factorsfor Plain Bearings
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Determining Factorsfor Plain Bearings
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Guide for Plain Bearing materials
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Selection Guide for Lubricants
The viscosity of a lubricating oil in a grease
the base oil viscosity is decisively for the
right thickness of the lubricating film (approx.
3-30µm) under con- sideration of the type of
lubricant supply.
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Lubricant supply
Depending on the demands, very different ways of
Lubrication may be used
l permanent oilcirculation lubrication
l interval lubrication
l for-life lubrication
l self-lubrication
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Permanent oil circulation withsimultaneous heat
dissipation
l car engines
l steam and water turbines
Standard is an oil pressure between 0,5 and 5
bar. If higher pressure is used it is called
forced-oil lubrication.
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Interval Lubrication
Lubrication in determined time intervals with oil
or grease
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For-life Lubrication(maintenance free)
l sintered bearings (oil-impregnated)
l lubricant depot (lubricant grooves/lubricant
pockets)
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Self Lubrication
Plain bearing materials based on thermo-plastics
with additives like MoS2
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OKS Speciality Lubricantsfor Plain Bearings with
primary requirements
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OKS Speciality Lubricantsfor Plain Bearings with
secondary requirements
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Thank You for Your Attention