Fujitec MO-1330 - Page 16

■ Theory of electic screwdriver torque
①Relation between dynamic torque and static torque.
Torque generated by screwdeiver varies depending
on scwer types ( iron tapping, plastic tapping,
machine screw ) and torque measurement methods
as shown in the chart on the right.
The relationship between these torque values is not
fixed, but the following formula is usually Applied:
Torque checker value ≦ Plastic tapping
≦ static torque (TS) ≦ Iron tapping
＜ Machine screw
②Relation between theoretical value (static torque ) and actual fastening torque (dynamic torque )
（Ex：MO-1330B）
(0.48)
(2.33)
0
2.5
2.0
1.5
1.0
0.5
2
4
6
8
10 （トルク目盛）
Torque checker
Static torque
Iron
board
Machine
Plasti
c
Torque
( N.m)
Theoretical value for MO-1330B
( Static torque )
( See page 9)
Machine
screw
Torque ( dynamic torque )
added by inertial energy of
motor rotor ( Increased by
10-50% of theoretical
value )
( NOTE )
S-shaped curve indicating
actual
fastening torque results form
torque knob property
Torque checker
Plastic tapping screw
Torque loss by screw surface friction and elasticity of
workpiece ( Decreased by 0-20% of theoretical value)
( Torque calibration )
－15－