A thrust bearing is a particular type of rotary bearing. Like other rotary bearings they permit rotation between parts, but they are designed to support a high axial load while doing this.
Thrust bearings come in several varieties.
 Ball thrust bearings
Roller thrust bearings
Tapered roller bearings
Fluid bearings,
Magnetic bearings
Fluid-film thrust bearings were invented by Australian engineer George Michell (pronounced Mitchell) who patented his invention in 1905. Michell bearings contain a number of sector-shaped pads, arranged in a circle around the shaft, and which are free to pivot. These create wedge-shaped regions of oil inside the bearing between the pads and a rotating disk, which support the applied thrust and eliminate metal-on-metal contact.
Michell's invention was notably applied to the thrust block in ships. The small size (one-tenth the size of old bearing designs), low friction and long life of Michell's invention made possible the development of more powerful engines and propellers. They were used extensively in ships built during World War I, and have become the standard bearing used on turbine shafts in ships and power plants worldwide.
http://en.wikipedia.org/wiki/File:Self-aligning-roller-thrust-bearing_din728_ex.png
http://upload.wikimedia.org/wikipedia/commons/d/d5/Thrust-ball-bearing_din711_ex.png
http://en.wikipedia.org/wiki/File:Fluid_thrust_bearing.PNG
Bearings In each stage of the standard configuration the impeller shroud and the diffuser act as bearing surfaces, in addition the upper and lower journal bearing of each pump section are supplied in Tungsten Carbide for added rotection against abrasion and vibration.
In submersible motors, the thrust bearing supports the pump's thrust weight of the water column being lifted by the pump. In standard water well motors this thrust bearing is a water lubricated "Kingsbury" type of bearing. A very small film of water between the main elements of the thrust bearing provides lubrication between the two bearing surfaces. If the motor overheats for any reason, this water film can approach its boiling point. If it boils, the lubricating film is lost. At this point, the bearing surfaces come into contact with each other and rapid heating takes place. Catastrophic failure of the thrust bearing is likely to occur.
|
|
Stator failure is another problem that occurs when motors overheat. Typical wet wound, water-filled submersibles use a PVC insulation that insulates the copper windings while immersed in water. This wire usually has a maximum usable temperature of between 70 C for standard motors to about 100 C for higher temperature motors. Once these temperatures are exceeded, the insulation system is damaged and a winding turn to turn, winding phase to phase or winding phase to ground fault becomes likely. Once these faults develop, failure of the motor is unavoidable.ditions with
A LOW FRICTION, HIGH-CAPACITY, IMPACT-RESISTANT THRUST BEARING
Thrust bearings are developed as a high capacity alternative to plain thrust bearings for submersible pumps which are subject to extremely harsh operating conditions that include high unit loads, speeds, impact and vibrations. They are especially manufactured for submersible motors to meet varying load conditions of bore-wells. It offers advantages of simplicity, compactness, economy & low friction over a wide load range.
Features of Efficient Thrust Bearing:
Thrust bearing allows to start motor even at low electric voltage.
Helps to save electric power due to less friction
Expanded speed & load combinations
Tolerates much higher impact load & shock load than conventional bearing.
Noise & wear free running with no vibrations
Virtually unlimited bearing life if correctly used.
Lower friction due to excellent finish & hydrodynamic lubrication results in reduced heat generation which in turn helps the motor to run at good RPM in high stage
Due to excellent quality raw material & processes super thrust bearing neither breaks nor burns
Properly hardening of steel / stainless steel increases versatility & extended operational life
|
|
