Rolling contact bearing (1)

Rolling contact bearing

1. A Seminar On “ Rolling Contact Bearings ” Presented By Amol Dhangar ( TEMA117) Rohan Ghadage (TEMA118) Rushikesh Honkhambe (TEMA119) Dipak Jadhav (TEMA120) Lalit Jadhav (TEMA121) Jalal Hatim (TEMA122) Under the guidance of Prof. S.N Khetre Department Of Mechanical Engineering NUTAN MAHARASHTRA INSTITUTE OF ENGINEERING AND TECHNOLOGY TALEGAON , PUNE-410506 (INDIA) [2017-2018] 1

2. Contents Introduction Types of bearings Construction of bearing Classification Advantages Disadvantages Applications Conclusion Referances 2

3. Introduction to bearings Objective of bearing is to provide relative positioning and rotational freedom while transmitting a load between two parts. In rolling contact bearings as the name implies the friction is of rolling type. It is much smaller than the sliding type 3

4. Types o f b e a r i n g s 4 Rolling Contact Bearings load is transferred through rolling elements such as balls, straight and tapered cylinders and spherical rollers. Journal (sleeve) Bearings load is transferred through a thin film of lubricant (oil).

5. Rolling Contact Bearings 05 R oll i ng c o n t a c t b e a r i ng s a r e a l so k no w n a s an t i f r i c t i on bearings. The load, speed, and operating viscosity of the lubricant affect the friction characteristics of a rolling bearing. T hese b e a r i ng s p r o v i d e c oef fi c i e n t s of f r i ct ion b e t we en 0.001 and 0.002. The designer must deal with such matters as fatigue, friction, heat, lubrication, kinematics problems, material properties, machining tolerances, assembly, use and cost

6. Construction of bearing 6 The rolling contact bearings are composed of four elements. Outer race Inner race Rolling element Cage of retaining ring

7. Construction Diagram 7 Roller contact bearing With its parts Outer ring (or) Outer race Inner ring (or) inner race Rolling elements iv.Cage or retaining ring

8. Classification of rolling bearings 8 Classified into two types i.Ball Bearing Deep groove (Conrad) bearing Filling notch ball bearing Angular contact bearings (AC) ii. Roller Bearing Cylindrical bearings Needle bearings Tapered bearings Spherical bearings

9. 09 Ball Bearings Deep groove bearing Single row of deep groove ball bearing can combinational of radial and thrust load. Load capacity is limited by the number of balls Primarily designed to support radial loads, the thrust capacity is about 70% of radial load capacity

10. 10 Filling notch ball bearings Bearings have the same basic radial construction as Conrad type. However, a filling notch (loading groove) permits more balls to be used. Radial load capacity is 20 – 40% higher than Conrad type. Thrust load capacity drops to 20% (2 directions) of radial load capacity .

11. Angular contact Ball bearings (AC) The centerline of contact between the balls and the raceway is at an angle to the plane perpendicular to the axis of rotation. Used for high radial and thrust load applications 11

12. Roller Bearings Roller bearings have higher load capacity than ball bearings, load is transmitted through line contact instead of point contact. Helical rollers are made by winding rectangular material into roller. Due to inherent flexibility they are capable of taking considerable misalignment. A roller with length much larger than diameter is known as needle roller and are used where radial space is limited. Cage nay be absent in needle roller bearings. 12

13. 13 ROLLER BEARINGS

14. Bearing life Life number of revolution or hours of operation, at constant speed, required for the failure criterion to develop defines the number of revolution or hours of operation, at constant speed, in such a way that of the bearings tested (from the same group) will complete or exceed before the first evidence of failure develops. This is known as life. For ball bearings and spherical bearings: L 10 = 500 (hours) x 33.33 (rpm) x 60 = 10 6 = 1 million revolutions For tapered bearings manufactured by Timken: L 10 = 3000 (hours) x 500 (rpm) x 60 = 90 x 10 6 = 90 million revolutions Basic Dynamic Load Rating, C constant radial load that a group of bearings can carry for L 10 life. 14

15. Bearing Life 15

16. Merits of rolling element bearings Low starting and good operating friction torque Requiring less axial space Good low-temperature starting. Rapid replacement Good low-temperature starting. 16

17. Demerits of rolling element bearings Greater diametric space. More severe alignment requirements. Noisier normal operation. Finite life due to eventual failure by fatigue. Poor damping ability 17

18. Conclusion Studied General information about Helical gear and its terminologies. Advantages over the spur gear and disadvantages. Composition, microstructure , hardness & case depth found satisfactory. Fractographic features indicated that fatigue was the main failure cause .] Misalignment was observed which has caused failure. Formation of destructive pitting and spalling at one end was due to load concentration at that area. 18

19. REFERANCES 19 Bhandari , V. B. Machine Design data book, Tata McGraw Hill Publication Co. Ltd. A Textbook of Machine Design By R. S. Khurmi & J. K. Gupta 3) Technical Publications: Design of Machine Elements 2.

20. THANK YOU ! 20