Abstract:

ESDU 82023 provides a general method for determining the minimum size of cam to suit a given application. Input information required includes the timing chart, the rotation speed, the cam law and the variation of follower load through the cycle. Then, for roller followers, by means of a geometric construction that minimises the contact stresses (by associating zero pressure angle with the position of the maximum load) the offset and cam prime circle radius are established for a chosen maximum value of pressure angle. The roller radius is determined from contact stress and interference considerations. For flat-faced followers, the minimum cam profile radius of curvature is fixed by eliminating high contact stresses and undercutting. Comprehensive practical worked examples illustrate the use of the method for both roller and flat-faced followers.