Page 361 - Cam Design Handbook

THB11 9/19/03 7:34 PM Page 349

CAM SYSTEM MODELING 349

FIGURE 11.22. Valve-gear components.

¥
.
6
EA (3010 psi )(0 075 in 2 )
.
¥
K = = = 47 10 lb in
5
vs
L 475 in
.
.
¥
6
EA (3010 psi )(0 075 in 2 )
.
K = = = 3010 lb in
¥
5
pr
L 74 in
.
All of the compliances act like springs in series, and hence are dominated by the spring
with the smallest spring rate. Since the lowest rate belongs to the coil spring, this spring
becomes the most important spring element to retain in any single degree of freedom
model. The other two stiffnesses are so large relative to the coil spring that the pushrod
and valve stem may be reasonably modeled as rigid bodies. With the valve stem, the rocker