Bearings viva questions

1-Define the term Bearing-

A bearing is a machine element which reduces friction between two members, having relative motion with respect to each other. It's a device used to support and guide rotating, oscillating or sliding shaft.

2-What are the functions of bearings?

Answer- • Supports & guides the rotating parts

• Reduces the friction & hence no or less wear & tear in moving parts

• Reduces the noise

• Reduces the lubricants consumption

• Reduces the power consumption of an equipment where it is being used Its all about HP heaters.

3-Where do you find the application of bearings?

Answer-Bearings found applications in almost all type of industries from a small trimmer to big & big Machines.

4-What type of loads act on bearings?

Answer-

Bearings can take in both axial, radial directions with small misalignment What are the main types of bearings used in industries? Main types of bearings are Journal bearing & Rolling contact bearings

5-Briefly explain the Journal bearings used in Industries

Answer-

Journal or plain bearings consist of a shaft or journal which rotates freely in a supporting metal sleeve or shell. There are no rolling elements in these bearings. It is a cylindrical bush, add up of suitable material and containing properly machined ID and ODs.It is a part of shaft or pin that rotates inside the bearing. They handle high load and velocities because metal to metal contact is minimal due to oil film. Operation is smoother. They require large supply of lubricating oil. For high speed need forced cooling/lubrication there may be possibilities of failures of bearings in start up and shutdown.

6-Where do you find the applications of Journal bearings?

Answer-

Journal bearings used High speed & high load machines. In power plant journal bearings found application in; • Steam Turbine • Boiler feed pumps • Slat chain conveyors

7-What are the two types of Journal bearings?

Answer- • Oil lubricated: Used for high speed & high load carrying machines • Grease lubricated journal bearings: Used for High load & low speed machines

8-What are the different materials used for the manufacturing of Journal bearings?

Answer-

Materials used are Copper & its alloys, generally Gun metal, bronze White metal & Babbitt metal: A tin base alloy containing 88% of tin, 8% of antimony and 4% of copper & bismuth

9-Why do you select the copper based alloys for journal bearings?

Answer-

Because they have low co-efficient of friction.

10-What are the maximum operating temperature of the jaurnal bearings?

Answer- operated uptp 100-105 deg celcius.

11-Classify the rolling contact bearings.

Answer- A. Ball Bearings: · . Deep groove ball bearing Angular contact ball bearings • Thrust ball bearing Self-aligning ball bearing B. Roller Bearings: · Spherical roller bearing Cylindrical roller bearing Taper roller bearing C. Thrust Roller and Needle Bearings.