Hitachi DS 14DMR, Технические данные и руководство по обслуживанию, Страница: 21 / 59

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Model WH 14DMR
7-3-3. Bolt tightening torque characteristics
Figures 5-1 and 5-2 show 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. 8-3, "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 Figs. 5-1 to 5-4, the screws are being tightened directly into a steel plate;
accordingly, the torque goes up very abruptly in comparison with ordinary bolt tightening conditions.
* The following bolts were utilized:
Ordinary bolt; strength grade 4.8
High-strength bolt; strength 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)
Fig. 5-1
0 1
2 3
Tightening time: sec.
(Steel plate thickness
t = 25 mm))
M14 x 50
High-strength bolt
Ordinary bolt
T
ightening torque
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
0
0
20
40
60
80
100
N
.
m
120
140
1200
(1042)
1400
(1215)
160
1600
(1389)
0
1 2 3
Tightening time: sec.
(Steel plate thickness
t = 25 mm))
M12 x 45
High-strength bolt
Ordinary bolt
T
ightening torque
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
0
0
20
40
60
80
100
N
.
m
120
140
1200
(1042)
1400
(1215)
160
1600
(1389)
0 1 2
Tightening time: sec.
(Steel plate thickness
t = 10 mm))
M10 x 30
High-strength bolt
Ordinary bolt
T
ightening torque
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
kgf
.
cm
(in-lbs.)
0
0
20
40
60
80
100
N
.
m
120
140
1200
(1042)
1400
(1215)
160
1600
(1389)
3
kgf
.
cm
(in-lbs.)
kgf
.
cm
(in-lbs.)