Maintenance and inspection procedures
(5) Timing belt tension
Fig.5-12 ： Belt tension
The timing belt can satisfactorily convey the drive and keep a durable force only when it has an adequate tension.
The belt tension should not be too tight or too loose. Instead, it should be adjusted to a degree that elasticity is
felt when the belt is pressed with the thumb. If the belt tension is too weak, the belt loosening side will vibrate. On
the other hand, if the belt tension is too strong, a sharp sound will be heard and the belt tension side will vibrate.
The detailed adjustment (tension) is shown in
.
Check and adjust with the belt pressing force f and the slack amount d between spans.
Pressing force
The preset value and adjustment value in the sound wave type belt tension gauge
Note) The value given in the table is the value of proper tension. Because the tension declines by the infancy expansion when exchanged
to new belt, please adjust proper tension again after the operation for the about 100 hours when exchanged to new belt
Axis
Belt type
Span ： s
Slack ： d
Pressing force ： f
Remarks
J3
309-EV3GT-6
102
1.5
2
J4(motor side)
336-EV3GT-6
64
1.0
2
J4(shaft side)
282-EV3GT-12
74
1.2
4
Axis
Belt type
Preset value
Standard tension T(N)
M(g/m)
W(mm/R)
S(mm)
New belt
Used belt
J3
309-EV3GT-6
2.5
6
102
39-48
26-32
J4(motor side)
336-EV3GT-6
2.5
6
64
39-48
26-32
J4(shaft side)
282-EV3GT-12
2.5
12
74
80-97
53-65
T
T
T
T
ｆ ： Pressing force
ｓ ： Span
ｄ ： Slack
T ： Tension
