Machinery's Handbook, 31st Edition
300
Shafts p t = maximum allowable shearing stress under combined loading conditions in pounds per square inch (see Table 2) S = maximum allowable flexural (bending) stress, in either tension or compression in pounds per square inch (see Table 2) S s = maximum allowable torsional shearing stress in pounds per square inch (see Table 2)
T = maximum torsional moment in inch-pounds V = maximum transverse shearing load in pounds
For shafts subjected to pure torsional loads only, (16a) or . D B S K T 51 s t 3 = For stationary shafts subjected to bending only,
, S N K P 321 000 s t
3
(16b)
D B =
. S K M 102 m 3
(17)
D B =
For shafts subjected to combined torsion and bending,
. D B p K M K T 51 t m t 2 2 3 = + ^ h ^ h . , D B p K M N 51 63 000 3
(18a)
or
2
K P t
(18b) Formulas (16a) to (18b) may be used for solid shafts or for hollow shafts. For solid shafts the factor B is equal to 1, whereas for hollow shafts the value of B depends on the value of K which, in turn, depends on the ratio of the inside diameter of the shaft to the outside diam eter ( D 1 ÷ D = K ). Table 3 gives values of B corresponding to various values of K . For short solid shafts subjected only to heavy transverse shear, the diameter of shaft required is: (19) Formulas (16a), (17), (18a) and (19), can be used unchanged with metric SI units. Formula (16b) becomes: . D B S N K P 487 s t 3 = and Formula (18b) becomes: . . D B p K M N K P 51 955 t m t 2 2 3 = + ^ a h k Throughout the formulas, D = outside diameter of shaft in millimeters; T = maxi mum torsional moment in newton-millimeters; S s = maximum allowable torsional shearing stress in newtons per millimeter squared (see Table 2); P = maximum power to be transmitted in milliwatts; N = revolutions per minute; M = maximum bending moment in newton-millimeters; S = maximum allowable flexural (bending) stress, either in tension or compression in newtons per millimeter squared (see Table 2); p t = maximum allowable shearing stress under combined loading conditions in newtons per millimeter squared; and V = maximum transverse shearing load in t m 2 c h # = + ^ m . D S V 17 s =
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online