平键，是依靠两个侧面作为工作面，靠键与键槽侧面的挤压来传递转矩的键。平键分为普通型平键、薄型平键、导向型平键三种。普通型平键对中性好，定位精度高，折装方便，但无法实现轴上零件的轴向固定，用于高速或承受冲击、变载荷的轴；薄型平键用于薄壁结构和传递转矩较小的地方；导向型平键用螺钉把键固定在轴上，用于轴上的零件沿轴移动量不大的场合。
|
轴径
|
键
|
键 槽
|
|
d
|
b×h
|
宽 度
|
深 度
|
半径
|
b
|
偏 差
|
轴
|
毂
|
|
较松
|
一般
|
较紧
|
|
轴H9
|
毂D10
|
轴N8
|
毂JS9
|
轴毂P9
|
t
|
偏差
|
t1
|
偏差
|
最大
|
最小
|
6~8
|
2×2
|
2
|
+0.025
0
|
+0.060
+0.020
|
-0.004
-0.029
|
±0.0125
|
-0.006
-0.031
|
1.2
|
+0.1
0
|
1
|
+0.1
0
|
0.08
|
0.16
|
＞8~10
|
3×3
|
3
|
1.8
|
1.4
|
＞10~12
|
4×4
|
4
|
+0.030
0
|
+0.078
+0.030
|
0
-0.030
|
±0.015
|
-0.012
-0.042
|
2.5
|
1.8
|
＞12~17
|
5×5
|
5
|
3.0
|
2.3
|
0.16
|
0.25
|
＞17~22
|
6×6
|
6
|
3.5
|
2.8
|
＞22~30
|
8×7
|
8
|
+0.036
0
|
+0.098
+0.040
|
0
-0.036
|
±0.018
|
-0.015
-0.051
|
4.0
|
+0.2
0
|
3.3
|
+0.2
0
|
＞30~38
|
10×8
|
10
|
5.0
|
3.3
|
0.25
|
0.40
|
＞38~44
|
12×8
|
12
|
+0.043
0
|
+0.120
+0.050
|
0
-0.043
|
±0.0215
|
-0.018
-0.061
|
5.0
|
3.3
|
＞44~50
|
14×9
|
14
|
5.5
|
3.8
|
＞50~58
|
16×10
|
16
|
6.0
|
4.3
|
＞58~65
|
18×11
|
18
|
7.0
|
4.4
|
＞65~75
|
20×12
|
20
|
+0.052
0
|
+0.149
+0.065
|
0
-0.052
|
±0.026
|
-0.022
-0.074
|
7.5
|
4.9
|
0.40
|
0.60
|
＞75~85
|
22×14
|
22
|
9.0
|
5.4
|
＞85~95
|
25×14
|
25
|
9.0
|
5.4
|
＞95~110
|
28×16
|
28
|
10.0
|
6.4
|
＞110~130
|
32×18
|
32
|
+0.062
0
|
+0.180
+0.080
|
0
-0.062
|
±0.031
|
-0.026
-0.088
|
11.0
|
7.4
|
＞130~150
|
36×20
|
36
|
12.0
|
+0.3
0
|
8.4
|
+0.3
0
|
0.70
|
1.0
|
＞150~170
|
40×22
|
40
|
13.0
|
9.4
|
＞170~200
|
45×25
|
45
|
15.0
|
10.4
|
＞200~230
|
50×28
|
50
|
17.0
|
11.4
|
＞230~260
|
56×32
|
56
|
+0.074
0
|
+0.220
+0.100
|
0
-0.074
|
±0.037
|
0.032
-0.106
|
20.0
|
12.4
|
1.2
|
1.6
|
＞260~290
|
63×32
|
63
|
20.0
|
12.4
|
＞290~330
|
70×36
|
70
|
22.0
|
14.4
|
＞330~380
|
80×40
|
80
|
25.0
|
15.4
|
2.0
|
2.5
|
＞380~440
|
90×45
|
90
|
+0.087
0
|
+0.260
+0.120
|
0
-0.087
|
±0.0135
|
-0.037
-0.124
|
28.0
|
17.4
|
＞440~500
|
100×50
|
100
|
31.0
|
19.5
|
