Machinery's Handbook, 31st Edition
Metric Module Involute Splines 2355 Table 14. Tooth Thickness Modification es for Selected Spline Fit Classes
External Splines a Selected Fit Class
External Splines a Selected Fit Class
d
e
f
h
d
e
f
h
Pitch Diameter in mm, D
Pitch Diameter in mm, D
Tooth thickness modification (reduction) relative to basic tooth thickness at pitch diameter, es , in mm
Tooth thickness modification (reduction) relative to basic tooth thickness at pitch diameter, es , in mm
0.020 0.014 0.006 0.030 0.020 0.010 0.050 0.032 0.016 0.040 0.025 0.013 0.065 0.040 0.020 0.080 0.050 0.025 0.100 0.060 0.030
0 0 0 0 0 0 0 0
> 120 to 180 > 180 to 250 > 250 to 315 > 315 to 400 > 400 to 500 > 500 to 630 > 630 to 800
0.145 0.085 0.043 0.170 0.100 0.050 0.190 0.110 0.056
0 0 0 0 0 0 0
≤ 3
> 3 to 6 > 6 to 10 > 10 to 18 > 18 to 30 > 30 to 50 > 50 to 80 > 80 to 120
0.125 0.062
0.210
0.068 0.076 0.080
0.230 0.135 0.260 0.145 0.290 0.160
0.120 0 a Internal splines are fit class H and have space width modification from basic space width equal to zero; thus, an H/h fit class has effective clearance c v = 0. 0.072 0.036 > 800 to 1000 0.320 0.170 0.086 Note: The values listed in this table are taken from ISO R286 and have been computed on the basis of the geometrical mean of the size ranges shown. Values in boldface type do not comply with any documented rule for rounding but are those used by ISO R286; they are used in this table to comply with established international practice. Basic Rack Profiles: The basic rack profile for the standard pressure angle splines are shown in Fig. 6a, Fig. 6b, Fig. 6c, and Fig. 6d. The dimensions shown are for maximum material condition and for fit class H/h. Spline Machining Tolerances and Variations.— The total tolerance ( T + λ ), Table 15, is the sum of Effective Variation, λ , and a Machining Tolerance, T . Table 15. Space Width and Tooth Thickness Total Tolerance, ( T + λ ), in Millimeters
Spline Toler ance Class
Spline Toler ance Class
In these formulas, i* and i** are tolerance units based upon pitch diameter and tooth thickness, respectively: . . . . . . ** . . . i D for D D for D i S S 0001 045 0001 D 500 0001 0004 21 500 0001 045 0001 mm mm * bsc bsc 3 3 2 # = + = + = + _ ^ ^ h h i
Formula for Total Tolerance, ( T + λ )
Formula for Total Tolerance, ( T + λ ) 25i* + 100i**
4 5
10i* + 40i** 16i* + 64i**
6 7
40i* + 160i** Effective Variation: The effective variation, λ , is the combined effect that total index variation, positive profile variation, and tooth alignment variation has on the effective fit of mating involute splines. The effect of the individual variations is less than the sum of the allowable variations because areas of more than minimum clearance can have profile, tooth alignment, or index variations without changing the fit. It is also unlikely that these variations would occur in their maximum amounts simultaneously on the same spline. For this reason, total index variation, total profile variation, and tooth alignment variation are used to calculate the combined effect by the following formula: . F f F 06 millimeters p f 2 2 2 λ = + + β ^ ^ ^ h h h The above variation is based upon a length of engagement equal to one-half the pitch diameter of the spline; adjustment of λ may be required for a greater length of engagement. Formulas for values of F p , f f , and F β used in the above formula are given in Table 16. Machining Tolerance: A value for machining tolerance may be obtained by subtracting the effective variation, λ , from the total tolerance ( T + λ ). Design requirements or specific processes used in spline manufacture may require a different amount of machining toler ance in relation to the total tolerance.
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