Harmonic Drive FHA Mini Series, Руководство пользователя

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Chapter 2 Guidelines for sizing
FHA-mini
34
2-4-6 Effective torque and average speed
Effective torque and the average speed should also be reviewed.
(1) The effective torque should be less than allowable continuous torque specified by the driver.
(2) The average speed should be less than allowable continuous speed of the actuator.
Calculate the effective torque and the average speed of an operating cycle as shown in the former
figure.
T
m
: effective torque (N•m)
T
a
: maximum torque (N • m )
T
r
: load torque (N
•
m)
t
a
: acceleration time (s)
t
d
: deceleration time (s)
t
r
: running time at constant speed (s)
t: time for one duty cycle (s)
N
av
: average speed (rpm)
N: driving speed (rpm)
If the result is greater than the value in the table below, calculate once again after reducing the duty
cycle.
Model
Items
FHA-8C FHA-11C FHA-14C
-
30
-
50
-
100
-
30
-
50
-
100
-
30
-
50
-
100
Reduction ratio 1:30 1:50 1:100 1:30 1:50 1:100 1:30 1:50 1:100
Continuous torque N ･ m 0.75 1.5 2 1.8 2.9 4.2
3.5
(3.0)
4.7 6.8
Continuous speed r/min 117 70 35 117 70 35 100 60 30
Note: The values for 24VDC are in parenthesis.
•
Example 3: getting effective torque and average speed
The parameters are same as the example 1 and 2 for an FHA-11C-50.
(1) Effective torque
From the parameters of T
a
=T
d
=8.3 N
•
m,T
r
=0 N
•
m, t
a
=0.072 s, t
r
=0.14 s, t
d
=0.046 s, t=0.8 s,
As the value of Tm (3.21N • m) ecceeds its allowable continuous torque (2.9N•m), it is impossible to drive
the actuator continuously on the duty cycle. The following equation is introduced by converting the
equation for effective torque. The limitted time for one duty cycle can be obtained by substituting the
continuous torque for the T
m
of the following equation.
Substituting 8.3 N•m for T
a
, 8.3 for T
d
, 0 N•m for T
r ,
2.9 N•m for T
m
, 0.072 s for t
a
, 0.14 s for t
r
, and
0.046 s for t
d
:
Namely, when the time for one duty cycle is set more than 3.4 s, the effective torque [T
m
] becomes less
than 2.9 N•m, and the actuator can drive the load with lower torque than the continuous torque
continuously.
(2)
Average speed
From the parameters of N =100 r/min, ta=0.072 s, tr=0.14 s, td=0.046 s, t=0.97 s
As the speed is less than the continuous speed of FHA-11C-50, it is possible to drive it continuously on
new duty cycle.