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牙型
30°楔形防松螺纹的牙型应符合下图的规定（粗实线）。
外螺纹有普通螺纹(M)和MJ螺纹两种，其牙型应分别符合GB/T 192和GJB 3.1A的规定。
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公差和极限尺寸
30°楔形防松螺纹有两种配合公差：精密级(4H/4h)和中等级(6H/6g)。
30°楔形防松内螺纹斜面大径和斜面小径与其中径具有相同的公差值(4H或6H)。
30°楔形防松内螺纹公差带位置见图2(剖面线部分）。
精密级和中等级内螺纹涂镀前的公差和直径极限尺寸应分别符合表1和表2的规定。
表1和表2内的斜面大径和斜面小径数值是牙底斜面与牙侧延长相交所形成的理论直径值。
本标准不规定涂镀后内螺纹的直径极限尺寸及其检验方法。
M外螺纹的基本尺寸和公差(4h和6g)应分别符合GB/T 196和GB/T 197的规定。
MJ外螺纹的基本尺寸和公差(4h和6g)应符合GJB 3.1A的规定。
注：在用户允许条件下，内螺纹斜面小径的最小值可以小于表1和表2的规定下限。
表1 精密级（4H）内螺纹的涂镀前公差和直径极限尺寸
螺纹规格
斜面大径D
斜面小径D5
牙顶小径D1
斜面大径和斜面小径公差 TD
牙顶小径公差TD1
公称
直径
螺距
max
min
max
min
max
min
5
0.8
5.154
5.074
4.711
4.631
4.404
4.304
0.08
0.1
6
1
6.188
6.093
5.646
5.551
5.239
5.119
0.095
0.12
7
1
7.188
7.093
6.646
6.551
6.239
6.119
0.095
0.12
8
1
8.188
8.093
7.646
7.551
7.239
7.119
0.095
0.12
8
1.25
8.216
8.116
7.543
7.443
7.03
6.894
0.1
0.136
10
1
10.188
10.093
9.646
9.551
9.239
9.119
0.095
0.12
10
1.25
10.216
10.116
9.543
9.443
9.03
8.894
0.1
0.136
10
1.5
10.251
10.139
9.46
9.348
8.809
8.657
0.112
0.152
12
1.25
12.228
12.116
11.565
11.453
11.020
10.884
0.112
0.136
12
1.5
12.257
12.139
11.46
11.342
10.815
10.663
0.118
0.152
12
1.75
12.287
12.162
11.375
11.25
10.591
10.421
0 125
0.17
14
1.5
14.257
14.139
13.46
13.342
12.815
12.663
0.118
0.152
14
2
14.318
14.186
13.3
13.168
12.424
12.235
0.132
0.189
16
1.5
16.257
16.139
15.46
15.342
14.815
14.663
0.118
0.152
16
2
16.318
16.186
15.3
15.168
14.424
14.235
0.132
0.189
18
1.5
18.257
18.139
17.46
17.342
16.815
16.663
0.118
0.152
18
2
18.318
18.186
17.3
17.168
16.424
16.235
0.132
0.189
18
2.5
18.372
18.232
17.117
16.977
16
15.776
0.14
0.224
20
1.5
20.257
20.139
19.46
19.342
18.815
18.663
0.118
0.152
20
2
20.318
20.186
19.3
19.168
18.424
18.235
0.132
0.189
20
2.5
20.372
20.232
19.117
18.977
18
17.776
0.14
0.224
22
1.5
22.257
22.139
21.46
21.342
20.815
20.663
0.118
0.152
22
2
22.318
22.186
21.3
21.168
20.424
20.235
0.132
0 189
22
2.5
22.372
22.232
21.117
20.977
20
19.776
0.14
0.224
24
1.5
24.264
24.139
23.46
23.335
22.822
22.67
0.125
0.152
24
2
24.326
24.186
23.3
23.16
22.432
22.243
0.14
0.189
24
3
24.448
24.278
22.959
22.789
21.565
21.313
0.17
0.252
27
1.5
27.264
27.139
26.46
26.335
25.822
25.67
0.125
0.152
27
2
27.326
27.186
26.3
26.16
25.432
25.243
0.14
0.189
27
3
27.448
27.278
25.959
25.789
24.565
24.313
0.17
0.252
30
1.5
30.264
30.139
29.46
29.335
28.822
28.67
0.125
0.152
30
2
30.326
30.186
29.3
29.16
28.432
28.243
0.14
0.189
30
3.5
30.505
30.325
28.765
28.585
27.153
26.869
0.18
0.284
33
2
33.326
33.186
32.3
32.16
31.432
31.243
0.14
0.189
33
3.5
33.505
33.325
31.765
31.585
30.153
29.869
0.18
0.284
36
2
36.326
36.186
35.3
35.16
34.432
34.243
0.14
0.189
36
3
36.448
36.278
34.959
34.789
33.565
33.313
0.17
0.252
36
4
36.561
36.371
34.591
34.401
32.703
32.403
0.19
0.3
39
2
39.326
39.186
38.3
38.16
37.432
37.243
0. 14
0.189
39
3
39.448
39.278
37.959
37.789
36.565
36.313
0.17
0.252
39
4
39.561
39.371
37.591
37.401
35.703
35.403
0.19
0.3
注：螺纹牙侧位置决定螺纹中径的大小；螺纹中径决定牙底斜面的长短。在30°牙侧角和斜面倾角条件下，斜面大径和斜面小径与螺纹中径的数学关系为D2=2D-D5-0.866 025 404P。
表2 中等级（6H）内螺纹涂镀前的公差和直径极限尺寸
螺纹规格
斜面大径D
斜面小径D5
牙顶小径D1
斜面大径和斜面小径公差 TD
牙顶小径公差TD1
公称
直径
螺距
max
min
max
min
max
min
10
1.5
10.269
10.089
9.428
9.248
8.893
8.657
0.18
0.236
12
1.5
12.279
12.089
11.432
11.242
10.899
10.663
0.19
0.236
12
1.75
12.303
12.103
11.332
11.132
10.686
10.421
0.2
0.265
14
1.5
14.279
14.089
13.432
13.242
12.899
12.663
0.19
0.236
14
2
14.33
14.118
13.244
13.032
12.535
12.235
0.212
0.3
16
1.5
16.279
16.089
15.432
15.242
14.899
14.663
0.19
0.236
16
2
16.33
16.118
15.244
15.032
14.535
14.235
0.212
0.3
18
1.5
18.279
18.089
17.432
17.242
16.899
16.663
0.19
0.236
18
2
18.33
18.118
17.244
17.032
16.535
16.235
0.212
0.3
18
2.5
18.372
18.148
17.033
16.809
16.131
15.776
0.224
0.355
20
1.5
20.279
20.089
19.432
19.242
18.899
18.663
0.19
0.236
20
2
20.33
20.118
19.244
19.032
18.535
18.235
0.212
0.3
20
2.5
20.372
20.148
19.033
18.809
18.131
17.776
0.224
0.355
22
1.5
22.279
22.089
21.432
21.242
20.899
20.663
0.19
0.236
22
2
22.33
22.118
21.244
21.032
20.535
20.235
0.212
0.3
22
2.5
22.372
22.148
21.033
20.809
20.131
19.776
0.224
0.355
24
2
24.342
24.118
23.248
23.024
22.543
22.243
0.224
0.3
24
3
24.442
24.177
22.852
22.587
21.713
21.313
0.265
0.4
27
2
27.342
27.118
26.248
26.024
25.543
25.243
0.224
0.3
27
3
27.442
27.177
25.852
25.587
24.713
24.313
0.265
0.4
30
2
30.342
30.118
29.248
29.024
28.543
28.243
0.224
0.3
30
3.5
30.487
30.207
28.629
28.349
27.319
26.869
0.28
0.45
33
2
33.342
33.118
32.248
32.024
31.543
31.243
0.224
0.3
33
3.5
33.487
33.207
31.629
31.349
30.319
29.869
0.28
0.45
36
3
36.442
36.177
34.852
34.587
33.713
33.313
0.265
0.4
36
4
36.536
36.236
34.431
34.131
32.878
32.403
0.3
0.475
39
3
39.442
39.177
37.852
37.587
36.713
36.313
0.265
0.4
39
4
39.536
39.236
37.431
37.131
35.878
35.403
0.3
0.475
中等级公差只用于螺距不小于1.5mm的螺纹规格。
注：螺纹牙侧位置决定螺纹中径的大小；螺纹中径决定牙底斜面的长短。在30°牙侧角和斜面倾角条件下，斜面大径和斜面小径与螺纹中径的数学关系为D2=2D-D5-0.866 025 404P。
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