Hitachi WH 14DM, Технические данные и руководство по обслуживанию

Страница: 12 / 31

--- 9 ---
•
Thread diameter and appropriate tightening torque
Fig. 3
7-2-3. Bolt Tightening torque characteristics
Fig. 4 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. 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 Fig. 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.
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)
300
250
150
200
100
0
0
6
8
10 12
14
(9/16") (15/32") (3/8")
(5/16")
(1/4")
Thread diameter
3000
2500
2000
1500
1000
500
(2604 in-lbs.)
(2170 in-lbs.)
(1736 in-lbs.)
(1302 in-lbs.)
(868 in-lbs.)
(434 in-lbs.)
0
N
•
m
kgf
•
cm
Strength grade 12.9
(high-strength bolt)
Strength grade 8.8
(high-strength bolt)
Strength grade 6.8
(ordinary bolt)
Strength grade 4.8
(ordinary bolt)
16 mm
(5/8")
50
0
1
2
3 (sec.)
M12 x 45
(15/32" x 1-3/4")
Tightening time: sec.
(Steel plate thickness
t= 1" (25 mm))
High-strength bolt
Ordinary bolt
0
20
40
60
80
100
120
140
160
kgf
•
cm
(in-lbs.)
N
•
m
0
200
400
600
800
1000
1200
1400
1600
(174)
(347)
(521)
(694)
(868)
(1042)
(1215)
(1389)
0
1 2 3 (sec.)
M10 x 30
(3/8" x 1-3/16")
Tightening time: sec.
(Steel plate thickness
t= 3/8" (10 mm))
High-strength bolt
Ordinary bolt
0
20
40
60
80
100
120
140
160
kgf
•
cm
(in-lbs.)
N
•
m
0
200
400
600
800
1000
1200
1400
1600
(174)
(347)
(521)
(694)
(868)
(1042)
(1215)
(1389)
0
1 2 3 (sec.)
M8 x 30
(5/16" x 1-3/16")
Tightening time: sec.
(Steel plate thickness
t= 3/8" (10 mm))
High-strength bolt
Ordinary bolt
0
20
40
60
80
100
120
140
160
kgf
•
cm
(in-lbs.)
N
•
m
0
200
400
600
800
1000
1200
1400
1600
(174)
(347)
(521)
(694)
(868)
(1042)
(1215)
(1389)
Tightening torque Tightening torque Tightening torque
Fig. 4