Maintenance and inspection procedures 5-98
(7) Timing belt tension
Fig.5-14 ： 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
Axis
Belt type
Span ：
s (mm)
New belt
Used belt
Slack ： d
Pressing force ： f
Slack ： d
Pressing force ： f
RH-3FH series
J3
309-EV3GT-6
96
1.5
3
1.5
2
J4(motor side)
336-EV3GT-6
64
1.0
3
1.0
2
J4(shaft side)
282-EV3GT-12
74
1.2
6
1.2
4
RH-6FH series
J3
264-EV3GT-9
82
1.3
4
1.3
3
J4(motor side)
315-EV3GT-6
64
1.0
3
1.0
2
J4(shaft side)
363-EV3GT-12
95
1.5
6
1.5
4
RH-12FH series
J3
288-EV3GT-12
71
1.1
6
1.1
4
J4(motor side)
417-EV3GT-9
99
1.5
4
1.5
3
J4(shaft side)
456-EV3GT-20
121
1.9
10
1.9
7
RH-20FH series
J3
303-EV3GT-12
71
1.1
6
1.1
4
J4(motor side)
417-EV3GT-9
99
1.5
4
1.5
3
J4(shaft side)
456-EV3GT-20
121
1.9
10
1.9
7
Axis
Belt type
Preset value
New belt
Used belt
M(g/m)
W(mm/
S(mm)
Standard tension T(N)
Standard tension T(N)
RH-3FH series
J3
309-EV3GT-6
2.5
6
96
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
RH-6FH series
J3
264-EV3GT-9
2.5
9
82
59-73
40-48
J4(motor side)
315-EV3GT-6
2.5
6
64
39-48
26-32
J4(shaft side)
363-EV3GT-12
2.5
12
95
80-97
53-65
RH-12FH series
J3
288-EV3GT-12
2.5
12
71
83-101
53-65
J4(motor side)
417-EV3GT-9
2.5
9
99
60-73
40-48
J4(shaft side)
456-EV3GT-20
2.5
20
121
138-151
88-108
RH-20FH series
J3
303-EV3GT-12
2.5
12
71
83-101
53-65
J4(motor side)
417-EV3GT-9
2.5
9
99
60-73
40-48
J4(shaft side)
456-EV3GT-20
2.5
20
121
138-151
88-108
T
T
T
T
ｆ ： Pressing force
ｓ ： Span
ｄ ： Slack
T ： Tension
