05-06-2012, 01:10 PM
Design and manufacture of “White Metal Thrust Bearing”
Abstract of the project :
White metal bearings transmit the thrust exerted by shafts rotating at high speeds to the foundation of the machine. White metal thrust bearings were invented by Anthony Michell in 1905. Here, pads are used instead of rollers or balls and the bearing housing is flooded with a hydrodynamic fluid under pressures of about 100 bar in order to minimize frictional losses. This also results in an increased load bearing capacity. This type of bearing holds many advantages over ball and roller contact thrust bearings.
Principle of operation
Thrust bearings support axial loads developed by rotating shafts. During rotation of the shaft, the lubricant is forced into the bearing gap, forming
a thin hydrodynamic layer between bearing surfaces, thus restricting metal to metal contact with each other directly. This reduces friction drastically and also wear and tear of parts.
Thrust bearing shaft diameters range from 20mm to 1000mm and they can handle loads ranging from 0.5 to 500 tons. The lubricant pressure inside the housing is about 1 bar and the maximum sliding speed of the tilt pads is 50 m/s. The velocity of lubricant flowing through the bearing passages is approximately 3m/s and they can handle temperatures as high as 120 C.
At startup, the load carrying capacity of the bearing is only 60% of the maximum permissible load. Due to high speed rotations, the hydrodynamic pressure between the bearing surfaces rises to 100 bar.
White metal coating is given to reduce friction b/n bearing surfaces. White metal has a very long life and they allow momentary overloads. In the event of misalignment, they conform and compensate, thus, avoiding any major damage to equipment.
6. Place of work: BABBITT ENGG. Pvt. Ltd.
IYD Campus, Arishinakunte,
Tumkur Road, Nelamangala Town,
Bangalore-562 123.
7. Probable date of completion of project: 30/4/2012.
