PRESENTATION ON

CAMS WITH SPECIFIED CONTOURS

GUIDED BY:- Prof. Hardik PatelKinematics of Machines

SUBMITTED BY:HIMANSHI GUPTA(140120119057) / ME / A1PRACHI SHARMA(140120119216) / ME / A1VIDISHA VYAS(140120119253) / ME / A1

(2131906)

GANDHINAGAR INSTITUTE OF TECHNOLOGY

INTRODUCTION

• A cam is a rotating machine element which gives reciprocating or oscillating motion to another element known as follower

• Cam and follower constitute higher pair• Cam-uniform speed• Follower-pre-determined motion

CAMS WITH SPECIFIED CONTOURS

• When the follower moves with the specified motion, the shape of the cam profile thus obtained is difficult and costly to manufacture

• So cams with specified contours are specified and motion of follower is determined

• Cam profiles consisting of circular arcs and straight lines are preferred

TANGENT CAM WITH RECIPROCATING ROLLER FOLLOWER

TANGENT CAM:-• Flanks of the cam are straight and tangential to

the base circle and nose circle• Used for operating inlet and exhaust valve of

IC Engines

• Two cases for derivation of displacement, velocity and acceleration expressions:

1. When the roller has contact with the straight flanks

2. When the roller has contact with the nose

TANGENT CAM WITH RECIPROCATING ROLLER FOLLOWER

• Terms used:

TANGENT CAM WITH RECIPROCATING ROLLER FOLLOWER

• CASE 1: WHEN THE ROLLER HAS CONTACT WITH STRAIGHT FLANK

Displacement:

Velocity is given by:

Velocity is maximum where θ is maximumThis happens when roller just leaves the contact with the straight flank at G i.e. when θ=ф

Acceleration is given by:-

• CASE 2: WHEN THE ROLLER HAS CONTACT WITH THE NOSE

DISPLACEMENT:

• VELOCITY

• ACCELERATION

• The velocity is zero at H and maximum at G• The acceleration is minimum at H and

maximum at G