37
<Inertia for motor shaft>
At gear input side
At gear output side
J
L2
J
L1
J
L1
J
L3
J
L3
J
L3
J
L2
J
L3
2
P
B
J
L1
=
M
2π
R
or
Linear Motion
Rack & Pinion Chain and Timing Belt
Speed
Speed
Torque
Torque
Cycle time
t
(
s
)
0
2π
N
M
(
J
M
+
J
L
)
2
Solid cylinder
8
1
32
L
(m)
V
T
p
T
L
T
S
t
a
t
c
t
m
t
e
t
d
N
=
N
M
=
N
R
V
P
B
R =
(
tm
–
ta
)
Where
t
a
=
t
d
,
d
p
: Pitch diameter (m)
Z
p
: Number of gear
L
p
: Pitch (m)
P
B
= Zp
Lp or π
dp
R =
60 2
Vt
a
+ 2
t
c
+
t
d
60
V
T
L
=
J
L
=
J
L1
+
J
L2
+
J
L3
J
K
=
M
K
D
2
J
K
=
L
D
4
J
L2
=
J
K
J
L3
=
J
K
R
2
t
am
=
2π
N
M
(
J
M
+
J
L
)
t
dm
=
2π
N
M
T
L
60
P
0
=
2π
60
N
M
P
a
=
J
L
t
a
2π
N
M
(
J
M
+
J
L
)
60
×
t
a
T
P
=
+
T
L
2π
N
M
(
J
M
+
J
L
)
60
×
t
d
T
S
=
–
T
L
T
P
2
t
a
+
T
L
2
t
c
+
T
S
2
t
d
T
rms
=
t
D
(m)
1/R
W
1/R
dp, Zp
dp, Zp
W
Lp
Lp
Selection of Servomotor Size
Motions
Mechanical Configuration
Speed Diagram
Travel Distance (m)
Min. Starting Time
(
S
)
Min. Braking Time
(
S
)
Running Power
(
W
)
Acceleration Power
(
W
)
Load axis speed
(min
-1
)
Motor Speed (min
-1
)
Effective Load Torque at
Motor Shaft
(
N
m
)
Required Starting Torque
(
N
m
)
Required Braking Torque
(
N
m
)
Effective
Torque
(
N
m
)
Effective Load Inertia at
Motor Shaft (kg
m
2
)
Linear Motion
M
K
: Mass (kg)
: Density (kg/m
3
) Iron
Aluminum
Rotational Motion
2π
R
µ
µ
: Load axis speed (min
-1
)
: Load speed (m/min)
:
Effective load torque at motor shaft (N
m)
: Friction coefficient
µ
N
V
T
π
9.8
×
M
P
B
+ 2π
T
µ
60
(
T
M
–
T
L
)
M
:
Mass of linear-motion unit (kg)
1/R
:
Gear ratio
η
:
Combined efficiency
T
M
:
Servomotor maximum torque (N
m)
60
(
T
M
+
T
L
)
= 7.87 × 10
3
(
kg/m
3
)
= 2.70
× 10
3
(
kg/m
3
)