Hitachi WH 12DAF, Технические данные и руководство по обслуживанию

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6-2-2. Bolt Tightening Torque Characteristics
Figure 2 shows relationships between time and tightening torque for individual bolt types and sizes. While the
data are useful for handy reference, actual tightening torque will vary depending on tightening conditions and
other variables. For details, please refer to Para. 7-3, Tightening Torque Variation.
(Note)
The term "tightening time" indicates the impact time after the lower surface of the bolt has come in contact
with the material into which it is being tightened.
In the tightening conditions shown in Fig. 2, the screws are being tightened directly into a steel plate;
accordingly, the torque goes up very abruptly in comparison with ordinary bolt tightening conditions.
Model WH 12DAF
Bolt
Nut
Steel plate thickness: t
* The following bolts were utilized:
Ordinary bolt; strength grade 4.8
High-strength bolt; strengh grade
12.9
Strength grade is read as follows:
4.8
Yield point or durable force:
(45,500 psi)
Tensile strength of the bolt:
(56,900 psi)
Washer
Ordinary bolt
High-strength bolt
15/32" x 1-3/4"
(M12 x 45)
Tightening time: sec
(Steel plate thickness:
t = 3/8" (10 mm))
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
1200
(1042)
(kgf
•
cm)
(in-lbs.)
Tightening torque
0
0 1 2 3
20
40
60
80
120
100
0
N
•
m
Ordinary bolt
High-strength bolt
3/8" x 1-3/6"
(M10 x 30)
Tightening time: sec
(Steel plate thickness:
t = 3/8" (10 mm))
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
(kgf
•
cm)
(in-lbs.)
Tightening torque
0
0 1 2 3
20
40
60
80
100
0
N
•
m
Ordinary bolt
High-strength bolt
5/16" x 1-3/6"
(M8 x 30)
Tightening time: sec
(Steel plate thickness:
t = 3/8" (10 mm))
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
(kgf
•
cm)
(in-lbs.)
Tightening torque
0
0
1
2 3
20
40
60
80
100
0
N
•
m
Washer
Fig. 2