Maintenance and inspection procedures
(8) 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.
F
■ RV-4F series
The preset value and adjustment value in the sound wave type belt tension gauge
■ RV-7F series
The preset value and adjustment value in the sound wave type belt tension gauge
■ RV-7FLL
The preset value and adjustment value in the sound wave type belt tension gauge
■ RV-13F/20F
The preset value and adjustment value in the sound wave type belt tension gauge
Axis
Belt type
Preset value
Standard tension (N)
Note1)
Note1) The value inside the parenthesis shown in the column of tension of the J1 axis shows the force which pulls the motor plate
hook at belt adjustment.
M(g/m)
W(mm/R)
S(mm)
New belt
Used belt
J1
315-3GT-12
2.5
12
85.5
79.7 - 97.4
(80 - 98)
53.1 - 64.9
(53 - 65)
J3
369-3GT-6
2.5
6
118.4
39.2 - 47.9
26.1 - 31.9
J4
240-3GT-6
2.5
6
56.4
J5
393-3GT-4
2.5
4
149.8
27.0 - 33.0
18.0 - 22.0
J6
270-3GT-4
2.5
4
96.0
Axis
Belt type
Preset value
Standard tension (N)
Note1)
Note1) The value inside the parenthesis shown in the column of tension of the J1 axis shows the force which pulls the motor plate
hook at belt adjustment.
M(g/m)
W(mm/R)
S(mm)
New belt
Used belt
J1
405-5GT-15
4.0
15
107.5
129.6 - 158.4
(123 - 151)
86.4 - 105.6
(82 - 100)
J3
501-3GT-9
2.5
9
178.5
59.4 - 72.6
39.6 - 48.4
J4
237-3GT-6
2.5
6
54.9
39.2 - 47.9
26.1 - 31.9
J5
408-3GT-6
2.5
6
150.0
J6
270-3GT-4
2.5
4
96.0
27.0 - 33.0
18.0 - 22.0
Axis
Belt type
Preset value
Standard tension (N)
M(g/m)
W(mm/R)
S(mm)
New belt
Used belt
J4
252-3GT-9
2.5
9
60.0
59.4- 72.6
39.6 - 48.4
J5
408-3GT-6
2.5
6
150.0
39.2 - 47.9
26.1 - 31.9
J6
270-3GT-4
2.5
4
96.0
27.0 - 33.0
18.0 - 22.0
Axis
Belt type
Preset value
Standard tension (N)
M(g/m)
W(mm/R)
S(mm)
New belt
Used belt
J4
252-3GT-9
2.5
9
60.0
59.4- 72.6
39.6 - 48.4
J5
495-3GT-9
2.5
9
181.0
J6
330-3GT-6
2.5
6
111.0
39.2 - 47.9
26.1 - 31.9
f : Pressing force
s : Span
d : Slack
F : Tension