YASKAWA CPCR-MR08C Bulletin page 60

7.2 SERVOMOTOR SELECTION GUIDE
LINEAR MOTION
PART •Load speed : V g = 15 m/min -Number of feed : n = 60 cycles/min
_.,,_ 'Weight of linear motion part: M = 100kg -Feed length: _ = 0.1m
SERVO_ _,r_ _ ,_ _ _ "Length of ball screw : LB = 1.0m "Feed time: t==0.5s or below
Mu_._O_{0 _"'t_ .Diameter of ball screw: De =0.02m 'Friction Coefficient: /_=0.2
(__ BALL SCREW -Ball screw lead : PB = 0.01 m 'Machine efficiency : 7/= 0.8
•Reduction ratio : I/R = l/2 (including speed reducer)
•Speed reducer inertia : JG = 1 × l0 -4 kg'm 2
(1) Speed Diagram
(m/mm)_
t- 60 _ 60 _ l.o (s)
n 60
Assumes t,
= td
60 _ 60×0.1
- 0.5 - o.1 (s)
t. :
t_
V, 15
tc = 0.5--0.1;<2 = 0.3 (s)
(2) Rotating Speed
Vt 15 - 1500 (r/min)
Load shaft speed Nt - PB 0.0_
Motor shaft speed NM = N_ • R = 1500×2 = 3000 (r/min)
(3) Load Torque
9.8 ff • M-PB _ 9.8×0.2×100×0.01
= 0.195 (N.m)
TL = 21rR" 7] 27r X2X0.8
(4) Load Inertia
Linear motion part JL_ = M 2_R = 100x _,_)
= 0.633X10 -4 (kg.m 2)
Ball screw JB -- 32 p "LB'D_-
7r X7.87 X 10'X 1.0 X (0.02)'× (+)'
-- 32
= 0.309X10-'
(kg.m 2)
Speed reducer Jc = 1.0Xl0-' (kg.m 2)
Load inertia (motor shaft conversion)
JL = JLI+JB+Jc=I.942XlO -4 (kg.m 2)
(5) Load Running Power
27rNM • TL 27r X 3000 X 0.195
--
= 61.3 (W)
Po -- 60 60
(6) Load Acceleration Power
2
p. = (_2_r NM) 2 X JL ----t. 2(__0__._X3000) x 1.942X10-'0.1
= 191.7 (W)
(7) Temporary Servomotor Selection
(Selectoin condition)
• TL --_ Motor rated torque *
• Pa +Po= (lto2) × Motor rated output*
• Value when combining Servomotor with Servopack
• NM __ Motor rated speed
• JL --_ Allowable load inertia of Servopack
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