Lecture-Bearing & It's types - for students.pdf
- 1. BEARING
- 2. Function of a bearing: ⚫ The main function of a rotating shaft is to transmit power from one end of the line to the other. ⚫ It needs a good support to ensure stability and frictionless rotation. The support for the shaft is known as “bearing”. ⚫ The shaft has a “running fit” in a bearing. All bearing are provided some lubrication arrangement to reduced friction between shaft and bearing.
- 3. Bearings are classified under two main categories: 1) Rolling or anti-friction bearing : - ⚫ Due to less contact area rolling friction is much lesser than the sliding friction, hence these bearings are also known as antifriction bearing. 2) Plain or slider bearing : - ⚫ In which the rotating shaft has a sliding contact with the bearing which is held stationary. Due to large contact area friction between mating parts is high requiring greater lubrication.
- 5. Roller bearing Advantages: ⚫ Low starting friction ⚫ Ease of lubrication ⚫ Require less axial space ⚫ Rapid replacement ⚫ Warning of failure – Increased noise 1) Rolling contact Bearings:
- 6. Roller bearing Disadvantages: ⚫ Greater radial space ⚫ More severe alignment requirements ⚫ Finite life due to eventual failure of fatigue ⚫ Noisier normal operation ⚫ Poor damping ability 1) Rolling contact Bearings:
- 7. 1) Types of Rolling contact Bearings: i. Ball bearing Roller bearing ii. Roller bearing
- 8. 1) Rolling contact Bearings: Roller bearing
- 9. i. Ball Bearings: A ball bearing is type of rolling element bearing which uses balls to maintain the separation between the moving parts of the bearing. The purpose of a ball bearing is to reduce rotational friction and support axial and radial loads.
- 10. ii. Roller Bearings: Roller bearing use cylinder of greater length than diameter. It typically have higher radial load capacity than ball bearing but have low axial capacity and higher friction.
- 11. i. Types of ball bearings 1. Deep Groove Bearing Characteristics: - Good Radial load - Moderate Axial load - Good operating speed Applications: - Electric motors - Automobiles - compressors, gear boxes and pumps
- 12. i. Types of ball bearings 1. Deep Groove Bearing
- 13. i. Types of ball bearings 1. Deep Groove Bearing Single row deep grove Double row deep grove
- 14. i. Types of ball bearings 2. Angular contact Bearing Characteristics: - Good Radial load - Good Axial load - Good operating speed Applications: - Agricultural machinery - Chemical industry - Machine tool spindle
- 15. i. Types of ball bearings 2. Angular contact Bearing
- 16. i. Types of ball bearings 3. Self aligning bearing Characteristics: - Better Radial load - Poor Axial load - Moderate speed - Can accommodate slight shaft misalignment
- 17. i. Types of ball bearings 3. Self aligning bearing
- 18. i. Types of ball bearings 4. Ball Thrust bearing Characteristics: - Poor Radial load - Excellent Axial load - Good speed Applications: - Aircraft engine - Impellers and propellers
- 19. i. Types of ball bearings 4. Ball Thrust bearing
- 20. ii. Roller Bearings: ⚫ They contain rollers to support the load. ⚫ Because of line contact, they can take greater loads ⚫ They also offer more rolling resistance. ⚫ Common types of roller bearings are; ⚫ Straight roller bearings ⚫ Tapered roller bearings ⚫ Spherical roller bearings ⚫ Needle Bearings
- 21. ii. Types of Roller bearings 1. Straight roller bearing Characteristics: - Excellent radial load - Poor axial load - Moderate to very good speeds Applications: - Conveyor belts to carry heavy loads
- 22. ii. Types of Roller bearings 2. Tapered Roller bearing Characteristics: - Good Radial load - Good Axial load - Moderate speed Applications: - Car wheel hubs (bearings can be mounted in pairs to support axial load in both directions)
- 23. ii. Types of Roller bearings 3. Spherical Roller bearing Characteristics: - Good Radial load - Poor Axial load - Good speed - Can accommodate slight shaft misalignment
- 24. ii. Types of Roller bearings 4. Needle bearing Characteristics: - Good Radial load - Poor Axial load - Moderate speed - Compact as compared to similar ball bearings Applications: - pumps, compressors, transmission, drive shaft etc.
- 25. 2) Types of Sliding contact Bearings: i. Journal bearing Roller bearing ii. Foot-step bearing iii. Collar bearing
- 26. 1. Journal bearing in this the bearing pressure is exerted at right angles to the axis of the shaft. This journal bearing is used for supporting a radial load. Shaft are generally made of mild steel. 2) Types of Sliding contact Bearings:
- 27. 1. Journal bearing 2) Types of Sliding contact Bearings:
- 28. 2. Foot-step bearing in this bearing the bearing pressure is exerted parallel to the shaft whose axis is vertical. Note that in this case the end of the shaft rests within the bearing. 2) Types of Sliding contact Bearings:
- 29. 3. Collar or Thrust bearing ⚫ In this bearing supporting pressure is parallel to the axis of the shaft having end thrust. Thrust bearing are used in bevel mountings, propeller drives, turbines, etc. note here the shaft, unlike foot-step bearing passes through and beyond the bearing. 2) Types of Sliding contact Bearings: