CAM AND FOLLOWER

1. Dept. of Mechanical Engg . Presented By: Ajay Savita ME-A(5 th SEM) Roll no: 0928ME121007 Ips-ctm

2. CAM AND FOLLOWER

3. 3 Cams Cams are used to convert rotary motion to oscillatory motion (almost always) or oscillatory motion to rotary motion (rarely) For high speed applications – example, internal combustion engines Objectives of this chapter: Learn fundamental concepts and terminology Learn how to design a cam and follower set to achieve a desired output motion.

4. Examples for cam In IC engines to operate the inlet and exhaust valves

5. Classification of CAM Mechanism Based on modes of Input / Output motion 1 Rotating cam – Translating follower 2 Rotating cam – Oscillating follower 3 Translating cam – Translating follower

6. 1 Rotating cam – Translating follower

7. 2 Rotating cam – oscillating follower

8. 3 Translating cam – Translating follower

9. Classification of cams a) Radial or disc cam b) Cylindrical cam c) End cam

10. a) Radial or Disc cam In radial cams, the follower reciprocates or oscillates in a direction perpendicular to the cam axis.

11. b) Cylindrical cams In cylindrical cams, the follower reciprocates or oscillates in a direction parallel to the cams axis.

12. c) End cams It is also similar to cylindrical cams, but the follower makes contact at periphery of the cam as shown in fig

13. Follower is the element to which the motion of cam is provided i.e. Reciprocating or oscillating motion WHAT IS FOLLOWER ?

14. Type of follower Motion Uniform Velocity The cam follower rises and falls at a constant speed. The start and stop of the follower is very abrupt and rough. Modified Uniform Velocity The modified uniform velocity motion smoothes out the roughness of the uniform velocity motion by adding a radius at the high and low points of the cam motion.

15. Type of follower Motion Harmonic Motion The follower motion has a smooth start and stop but the speed is not uniform. This type of motion is used where the cam rotates at a very fast speed. Uniform Acceleration The uniform acceleration is the smoothest motion of all of the cams and causes the follower to maintain a constant speed throughout the cam travel.

16. Classification of followers 1.According to the shape of follower Knife edge follower Roller follower Flat faced follower Spherical faced follower

17. a) Knife edge follower

18. b) Roller follower

19. c) Flat faced follower

20. d) Spherical faced follower

21. 2 According to the path of motion of follower Radial follower Offset follower

22. a) Radial follower When the motion of the follower is along an axis passing through the centre of the cam, it is known as radial followers. Above figures are examples of this type.

23. b) Offset follower When the motion of the follower is along an axis away from the axis of the cam centre, it is called off-set follower. Above figures are examples of this type.

24. 1. Reciprocating or Translating 2.Oscillating or Rotating 3.On the basis of motion of follower

25. CAM Nomenclature Cam profile: The outer surface of the disc cam. Base circle : The circle with the shortest radius from the cam center to any part of the cam profile. Trace point : It is a point on the follower, and its motion describes the movement of the follower. It is used to generate the pitch curve.

26. CAM Nomenclature Pitch curve : The path generated by the trace point as the follower is rotated about a stationery cam. Prime circle: The smallest circle from the cam center through the pitch curve

27. CAM Nomenclature Pressure angle: The angle between the direction of the follower movement and the normal to the pitch curve. Pitch point: Pitch point corresponds to the point of maximum pressure angle.

28. CAM Nomenclature Pitch circle: A circle drawn from the cam center and passes through the pitch point is called Pitch circle Stroke: The greatest distance or angle through which the follower moves or rotates

29. Thank you