15.3 Determining Drive Capacity
1
5
-13
As shown in Fig. 15.16, when performing drill processing, the blade is mounted to the main axis and ro-
tated, opening a hole in the material being processed, so the motive force
P
D
required can be expressed
using the following formula. The load torque
M
differs depending on the material, and the ratio of the drill
radius
D
: Feed speed
f
, so care must be applied.
P
D
=
M
⋅
2
π
n
60
×
100
×
1000
×
η
D
=
π
D
2
f
4
×
1000
×
S
D
η
D
(kW)
M
:
Drill load torque (N
⋅
cm)
n
:
Main axis speed (min
−
1
)
η
D
:
Machine efficiency 0.7 to 0.85
D
:
Drill radius (mm)
f
:
Feed speed (mm/min.)
S
D
:
Cutting efficiency (i.e., cutting amount per 1 kW per minute) (CC/kW/min.)
D
f
Fig 1
5
.
16
Example of Drill Processing
J
Gravity Load Drive
The motive force required to move a load such as a crane or loader vertically differs greatly depending on
whether or not a counterweight is used. The motive force in each case can be expressed using the following
formulas.
Without counterweight
P
GL
=
m
L
V
6120
η
(kW)
With counterweight
P
GLC
=
(
m
L
−
m
C
)
V
6120
η
(kW)
V
:
Vertical travel speed (m/min.)
η
:
Machine efficiency
m
L
:
Load mass (kg)
m
C
:
Counterweight mass (kg)
Motor
Drum
Speed
V
(m/min)
Load
m
L
(kg)
Motor
Speed
V
(m/min)
m
L
(kg)
m
C
(a) Without Counterweight
(b) With Counterweight
Fig 1
5
.
17
Gravity Loads
15