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ELEMENTS OF METRIC GEAR TECHNOLOGY
TABLE OF CONTENTS
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SECTION 17 STRENGTH AND DURABILITY OF GEARS ................................................................ T-150
17.1 Bending Strength Of Spur And Helical Gears............................................................ T-150
17.1.1 Determination of Factors in the Bending Strength Equation................ T-151
17.1.2 Tooth Profile Factor, Y F ............................................................................... T-151
17.1 3 Load Distribution Factor, Y e ....................................................................... T-151
17.1 4 Helix Angle Factor, Y b ................................................................................. T-153
17.1.5 Life Factor, K L ............................................................................................... T-154
17.1.6 Dimension Factor of Root Stress, K FX ....................................................... T-154
17.1.7 Dynamic Load Factor, K V ............................................................................ T-154
17.1.8 Overload Factor, K O ..................................................................................... T-155
17.1.9 Safety Factor of Bending Failure, S F ........................................................ T-155
17.1.10 Allowable Bending Stress at Root, s F lim ................................................. T-155
17.1.11 Example of Bending Strength Calculation............................................... T-159
17.2 Surface Strength Of Spur And Helical Gears............................................................. T-160
17.2.1 Conversion Formulas................................................................................... T-160
17.2.2 Surface Strength Equations....................................................................... T-160
17.2.3 Determination of Factors in the Surface Strength Equations............... T-160
17.2.4 Contact Ratio Factor, Z e ............................................................................. T-162
17.2.5 Helix Angle Factor, Z b ................................................................................ T-163
17.2.6 Life Factor, K HL .............................................................................................. T-163
17.2.7 Lubricant Factor, Z L ..................................................................................... T-163
17.2.8 Surface Roughness Factor, Z R .................................................................. T-163
17.2.9 Sliding Speed Factor, Z V ............................................................................. T-164
17.2.10 Hardness Ratio Factor, Z W ......................................................................... T-164
17.2.11 Dimension Factor, K HX ................................................................................. T-164
17.2.12 Tooth Flank Load Distribution Factor, K Hb ............................................... T-164
17.2.13 Dynamic Load Factor, K V ............................................................................ T-165
17.2.14 Overload Factor, K O ..................................................................................... T-165
17.2.15 Safety Factor for Pitting, S H ....................................................................... T-165
17.2.16 Allowable Hertz Stress, s H lim .................................................................... T-165
17.2.17 Example of Surface Stress Calculation.................................................... T-170
17.3 Bending Strength Of Bevel Gears................................................................................ T-171
17.3.1 Conversion Formulas................................................................................... T-171
17.3.2 Bending Strength Equations...................................................................... T-172
17.3.3 Determination of Factors in Bending Strength Equations..................... T-172
17.3.4 Examples of Bevel Gear Bending Strength Calculations...................... T-179
17.4 Surface Strength Of Bevel Gears................................................................................. T-180
17.4.1 Basic Conversion Formulas........................................................................ T-180
17.4.2 Surface Strength Equations....................................................................... T-180
17.4.3 Determination of Factors in Surface Strength Equations..................... T-181
17.4.4 Examples of Bevel Gear Surface Strength Calculations....................... T-184
17.5 Strength Of Worm Gearing............................................................................................ T-185
17.5.1 Basic Formulas............................................................................................. T-185
17.5.2 Torque, Tangential Force and Efficiency.................................................. T-186
17.5.3 Friction Coefficient, m ................................................................................. T-186
17.5.4 Surface Strength of Worm Gearing Mesh............................................... T-187
17.5.5 Determination of Factors in Worm Gear Surface Strength EquationsT-188
17.5.6 Examples of Worm Mesh Strength Calculation...................................... T-193
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