SYMBOLS

C _i, i = 0, 1, 2, n constant coefficients

h = maximum follower rise normalized

y = follower displacement, dimensionless

y ? = follower velocity, dimensionless

y ? = follower acceleration, dimensionless

= follower jerk, dimensionless

? = cam angle for rise, h, normalized

? = cam angle rotation normalized

4.1 INTRODUCTION

In Chap. 2, Basic Cam Curves, and Chapter 3, Modified Cam Curves, we presented two approaches for the engineers selection of an acceptable curve design. Now, we will include a third choice of cam curve, that is, the use of algebraic polynomials to specify the follower motion. This approach has special versatility especially in the high-speed automotive field with its DRRD action. Also included in this chapter is a selection of important Fourier series curves that have been applied for high-speed cam system action.

The application of algebraic polynomials was developed by Dudley (1952) as an element of polydyne cams, discussed in Chap. 12, in which the differential equations of motion of the cam-follower system are solved using polynomial follower motion equations. Stoddart (1953) shows an application of these polynomial equations to cam action.

The polynomial equation is of the form

(4.1)

For convenience Eq. (4.1) is normalized such that the rise, h, and maximum cam angle, ?, will both be set equal to unity. Therefore, for the follower:

Note that C _i are chosen so that the...