Machinery's Handbook, 31st Edition
2230 Spur Gearing Table 9a. Increase in Dedendum, Δ for 20 -, and 25 -Degree Pressure Angle Fine- Pitch Enlarged Pinions and Reduced Gears ANSI B6.7-1977 Diametral Pitch, P Δ Diametral Pitch, P Δ Diametral Pitch, P Δ Diametral Pitch, P Δ Diametral Pitch, P Δ 20 0.0000 32 0.0007 48 0.0012 72 0.0015 96 0.0016 24 0.0004 40 0.0010 64 0.0015 80 0.0015 120 0.0017 Δ = increase in standard dedendum to provide increased clearance. See footnote to Table 9d. Table 9b. Dimensions Required when Using Enlarged, Fine-pitch, 14 1 ∕ 2 -Degree Pressure Angle Pinions ANSI B6.7-1977, Information Sheet B
Standard Center-distance System (Long and Short Addendum)
Enlarged Center-distance System
Enlarged Pinion
Enlarged Pinion Mating with St’d. Gear
Reduced Mating Gear
Two Equal Enlarged Mating Pinions a
Contact Ratio of Two Equal Enlarged Mating Pinions
Contact Ratio, n Mating with N
No. of Teeth n
Outside Diame ter
Increase over St’d. Center Distance
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
13.3731 1.9259 1.3731 1.2157 14.3104 1.9097 1.3104 1.2319 15.2477 1.8935 1.2477 1.2481 16.1850 1.8773 1.1850 1.2643 17.1223 1.8611 1.1223 1.2805 18.0597 1.8448 1.0597 1.2967 18.9970 1.8286 0.9970 1.3130 19.9343 1.8124 0.9343 1.3292 20.8716 1.7962 0.8716 1.3454 21.8089 1.7800 0.8089 1.3616 22.7462 1.7638 0.7462 1.3778 23.6835 1.7476 0.6835 1.3940 24.6208 1.7314 0.6208 1.4102 25.5581 1.7151 0.5581 1.4265 26.4954 1.6989 0.4954 1.4427 27.4328 1.6827 0.4328 1.4589 28.3701 1.6665 0.3701 1.4751 29.3074 1.6503 0.3074 1.4913 30.2447 1.6341 0.2448 1.5075 31.1820 1.6179 0.1820 1.5237 32.1193 1.6017 0.1193 1.5399 33.0566 1.5854 0.0566 1.5562
54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33
1.831 1.847 1.860 1.873 1.885 1.896 1.906 1.914 1.922 1.929 1.936 1.942 1.948 1.952 1.956 1.960 1.963 1.965 1.967 1.969 1.970 1.971
0.6866 0.6552 0.6239 0.5925 0.5612 0.5299 0.4985 0.4672 0.4358 0.4045 0.3731 0.3418 0.3104 0.2791 0.2477 0.2164 0.1851 0.1537 0.1224 0.0910 0.0597 0.0283
1.3732 1.3104 1.2477 1.1850 1.2223 1.0597 0.9970 0.9343 0.8716 0.8089 0.7462 0.6835 0.6208 0.5581 0.4954 0.4328 0.3701 0.3074 0.2448 0.1820 0.1193 0.0566
1.053 1.088 1.121 1.154 1.186 1.217 1.248 1.278 1.307 1.336 1.364 1.392 1.419 1.446 1.472 1.498 1.524 1.549 1.573 1.598 1.622
1.646 a If enlarged mating pinions are of unequal size, the center distance is increased by an amount equal to one-half the sum of their increase over standard outside diameters. Data in this column are not given in the standard. b To maintain standard center distance when using an enlarged pinion, the mating gear diameter must be decreased by the amount of the pinion enlargement. All dimensions are given in inches and are for 1 diametral pitch. For other pitches divide tabulated dimensions by the diametrical pitch.
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online