2-4 Examining operating conditions
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付
S
e
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c
tion gui
de
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Load torque calculation
Calculate the load torque as follows:
Rotary motion
The rotary torque for the rotating mass W on the ring
of radius r from the center of rotation is shown in the
figure to the right.
T : Rotary torque (Nm)
μ
: Friction coefficient
W : Mass (kg)
r : Average radius of friction side (m)
The right graph gives a calculation example
when the friction coefficient μ is assumed as 0.1
and the horizontal axis and vertical axis
represent mass and rotational radius of friction
side, respectively. The actuator toque value
shown in the graph indicates 20% of the
maximum torque.
Linear operation (horizontal operation)
The rotary torque when the mass W moves horizontally due to the screw of pitch P is shown below.
T : Rotary torque (Nm)
μ
: friction coefficient
W : mass (kg)
P : Screw feed pitch (m)
Linear operation (vertical operation)
The rotary torque when the mass W moves vertically due to the screw of pitch P is shown below.
Mass: W
Pitch: P
Friction: μ
π
×
×
×
µ
×
=
2
P
W
8
.
9
T
π
×
×
×
=
2
P
W
8
.
9
T
Pitch: P
Mass: W
r
W
8
.
9
T
×
×
µ
×
=
Radius: r
Mass: W
Friction: μ
Example of rotary torque calculation (friction coefficient = 0.1)
SHA: 20% torque of maximum torque is shown.
10
1000
3000
100
Mass W (kg)
10
100
1000
R
adi
us
r
o
f
fr
ic
ti
on
s
ide (
m
m
)
10000
15 Nm
20 Nm
SHA25A51
SHA65A81
SHA40A51
SHA32A51
30 Nm
40 Nm
50 Nm
200 Nm
300 Nm
10 Nm
500 Nm
600 Nm
700 Nm
800 Nm
5 Nm
