•
Horizontal linear motion
The following formula calculates the torque for horizontal
linear motion of mass [W] fed by the screw of pitch [P].
T = 9.8 x
μ
x W x P
2 x
π
T
: torque (N
•
m)
μ
: coefficient of friction
W
:
mass (kg)
P
: screw pitch (m)
•
Vertical linear motion
The following formula calculates the torque for vertical
linear motion of mass [W] fed by the screw of pitch [P].
T = 9.8 x W x P
2 x
π
2-4-4
Acceleration time and deceleration time
Calculate acceleration and deceleration times for the selected actuator.
Acceleration: ta = (J
A
+ J
L
) x
2 x
π
x
N
60 T
M
– T
L
Deceleration: td = (J
A
+ J
L
) x 2 x
π
x
N
60 T
M
+ 2 x T
F
– T
L
Ta:
acceleration time (sec)
T
d
:
deceleration time (sec)
J
A
:
actuator inertia (kg
•
m
2
)
J
L
:
load inertia (kg
•
m
2
)
N:
actuator speed (r/min)
T
M
: maximum torque of actuator (N
•
m)
T
F
:
actuator friction torque at max. speed (N
•
m)
T
F
= K
T
x I
M
- T
M
where, K
T
: torque constant (N
•
m/A)
I
M
: maximum current (A)
T
L
:
load torque (N
•
m)
note that the polarity of the load torque is
plus (+) for counter direction of revolution,
and minus (-) for same direction.
•
Example
1
The load conditions are:
Rotary speed:
60r/min
Moment of inertia: 1.5 kg
•
m
2
Load torque is so small as to be neglected.
(1)
Referring the figure in section 2-1, FHA-25C-50 actuator is selected for the load.
(2)
Referring the specification table provided in section 1-4, J
A
=0.81 kg
•
m
2
, TM =150 N
•
m, K
T
=22 N
•
m/A,
and I
M
=7.3A are obtained for the FHA-25C-50.
(3)
T
F
= 22 x 7.3 – 150 = 10.6 N
•
m is obtained with the formula above.
(4)
Acceleration and deceleration times are:
ta = (0.81+1.5 ) x 2 x
π
/ 60 x 60 / 150 = 0.097 s
td = (0.81+1.5) x 2 x
π
/ 60 x 60 / (150 + 2 x 10.6) = 0.085 s
(5)
If the calculated acceleration times are too long, correct the situation by:
•
Reducing load moment of inertia
•
Selecting an actuator with a larger frame size
25
Chapter 2 Guidelines for sizing
Mass: W
Mass: W
Pitch: P
Pitch: P
Friction:
Speed
N
Time
ta
td
Summary of Contents for FHA Series
Page 2: ...FHA C series...
