Page 51 - Cam Design Handbook

THB2 8/15/03 12:48 PM Page 39

BASIC CURVES 39

Jerk y''' = • Displacement, y

Velocity, y' Dwell
y, y', y", y''' h

0 b
Cam angle q
Dwell

Acceleration, y"

FIGURE 2.6. Cubic no. 1 curve—DRD cam.

q
Ê ˆ 3
Displacement y = 4 hÁ ˜ (2.38)
Ë ¯
b
2
12 h q
Ê ˆ
Velocity y ¢ = Á ˜ (2.39)
b Ë ¯
b
24 h q
Ê ˆ
Acceleration y ¢¢ = Á ˜ (2.40)
b 2 Ë ¯
b
24 h
Jerk y ¢¢¢ = (2.41)
b 3
= constant
b
q
££ b
2
3
È Ê q ˆ ˘
14
Displacement y = h - Á1 - ˜ ˙ (2.42)
Í
Î Ë b ¯ ˚
12 h Ê q ˆ 2
Velocity y ¢ = Á1 - ˜ (2.43)
b Ë b ¯
24 h Ê q ˆ
Acceleration y ¢¢ =- Á1 - ˜ (2.44)
b 2 Ë b ¯
24 h
Jerk y ¢¢¢ = = constant (2.45)
b 3