Page 61 - Cam Design Handbook

THB2 8/15/03 12:48 PM Page 49

BASIC CURVES 49

Acceleration
n = 1.3
e
acceleration, y" n = 0.1 Velocity

e

Velocity, y' 0.5 Cam angle q/b 1.0

a e
FIGURE 2.14. Elliptical curve velocity and acceleration (n = ratio off axes).
b e

follower rises 1-1/2 inches in 150 degrees of dwell-rise-dwell cam rotation at 300rpm.
Table 2.1 presents the mathematical summary of the curve equations.

2.15 CURVE APPLICATION TO DRRD CAM

In this chapter we discussed the application of symmetrical basic curves to dwell-rise-
return-dwell (DRRD) cams. Much of the previous information on the use of basic curves
in dwell-rise-dwell cams applies to DRRD cams, with certain slight changes. DRRD cams
using the basic curves of this chapter for both rise and return may be classified as:
• Symmetrical rise and fall displacement curve, in which both the rise and the fall take
place in the same time or through the same cam angle.
• Asymmetrical rise and fall displacement curve (i.e., the cam angle of rise is different
from the cam angle of fall).