In flat collar bearing, why is the number of collars provided to carry a fixed axial load?

Concept:

Bearing

• A bearing is the machine element, which supports another moving machine element known as a journal.
• It permits relative motion between the contact surfaces of the members while carrying the load.

Classification of bearings:

Depending upon the direction of the load to be supported

• Radial bearing – The load acts perpendicular to the direction of motion of the moving element.
• Thrust bearing – The load acts along the axis of rotation. The bearing may move in either direction.

Thrust bearing

• A thrust bearing is used to guide or support the shaft which is subjected to a load along the axis of the shaft. Such types of bearings are mainly used in turbines and propeller shafts

There are two types of thrust bearings

• Footstep or pivot bearing – The loading shaft is vertical and the end of the shaft rests within the bearing.
• Collar bearing – The shaft continues through the bearing. The shaft may be vertical or horizontal with a single collar or many collars.

Flat collar bearings

• The shaft may be vertical or horizontal with single or multiple collars.
• In designing collar bearings, it is assumed that the pressure is uniformly distributed over the bearing surface.
• The bearing pressure for a single collar and water-cooled multi-collared bearings may be taken the same as footstep bearings.
• Collar bearings are thrust bearing having a suitably formed face or faces that resist the axial pressure or decrease the intensity of pressure of one or more collars on a rotating shaft.

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