CYLINDRICAL WORM GEAR PAIR
CALCULATION REPORT
Order Dware
Project WormGear
Sub project Niemann-Winter Band III
Item Beispiel 3 Page 102
ID worm z_1 = 1
ID gear z_2 = 40
Calculated by Andr Dewispelaere
Company Dware
On date 23/05/2020

Input operating conditions Symbol Unit Worm Wheel
Desired service life Lh h 25000 25000
Service factor ID % 100.00 100.00
Roughness worm flanks Ra1 m 0.800 --
Kinematic viscosity at 40 C oil ν40 mm/s 320 320
Kinematic viscosity at 50 C oil ν50 mm/s 169 169
Oil type -- -- mineral mineral
Wheel transverse force alternating -- -- no no
Short operation time -- -- no no
Short operation time duration tE min s 0 min 0 s 0 min 0 s
Short shocks duration < 15 s -- -- no no

Input application factor Symbol Unit Worm Wheel
Application factor KA -- 1.00 1.00
Input cooling conditions Symbol Unit Worm Wheel
Highest allowed oil temperature θL C 95 95
Ambient temperature θi C 20 20
Heat exchange area Aca m 2.9000 2.9000
Heat exchange coefficient kca kW/m 0.028 0.028
Enclosed in housing -- -- yes yes
Cooling ribs on housing -- -- yes yes
Forced ventilation -- -- yes yes
Riding wind on housing -- -- no no
Riding wind velocity vai m/s 0.00 0.00
Desired wear limit Symbol Unit Worm Wheel
Wear limit in tooth thickness DsnL mm 0.000 0.000
Wear limit in mass DmL kg 0.100 0.100
Desired min safety factors Symbol Unit Worm Wheel
Safety thermal overload ST -- -- 1.00
Safety contact stress wheel SH -- -- 1.00
Safety wear on wheel dent SW -- -- 1.00
Safety tooth root strength wheel SF -- -- 1.40
Safety deflection worm shaft Sd -- 1.00 --
Input mating materials Symbol Unit Worm Wheel
Materials mating factor WP -- 1.10 1.10
Material mating test velocity vg0 m/s 0.13 0.13
Calculation of cooling Symbol Unit Worm Wheel
Permissible temperature raise θuP C 63.6 63.6
Heat exchange surface area Aca m 2.9000 2.9000
Heat exchange coeffcient kca kW/m 0.0276 0.0276
Heat exchange flow Qab kW 5.091 5.091
Total power loss PV kW 4.953 4.953
Safety factor thermal overload ST -- 1.03 1.03
Calculation contact stress Symbol Unit Worm Wheel
Elasticity factor ZE /N/mm 152.50 152.50
Worm diameter ratio d1/a -- 0.33 --
Contact factor Zρ -- 2.979 2.979
Calculated contact stress σH N/mm -- 241.8
Effective service life Lhc h -- 25000
Life factor Zh -- -- 1.000
Load cycles factor Zn -- -- 0.805
Endurance contact stress σHlim N/mm -- 733
Permissible contact stress σHP N/mm -- 590
Safety factor contact stress SH -- -- 2.44
Calculation wear stress Symbol Unit Worm Wheel
Projected tooth face area worm Ap2 mm -- 1280
Tooth wear surface area wheel Az2 mm -- 1372
Wear loss limit in mass Dmlim kg -- 0.100
Number of load cycles NL Mcy -- 56.250
Wear endurance stress σWlim N/mm -- 82.5
Wear roughness factor WR -- -- 0.99
Wear friction velocity vg1 m/s -- 6.59
Wear velocity factor Wv -- -- 3.14
Permissible wear stress σWP N/mm -- 281.2
Safety factor wear on wheel SW -- -- 1.16
Calculation tooth root strength Symbol Unit Worm Wheel
Face width at tooth root b2 mm -- 70.00
Transverse tangential force Ft2 kN -- 21.237
Calculated tooth root stress σF N/mm -- 29.1
Alternating load factor YA -- -- 1.00
Endurance tooth root stress σFlim N/mm -- 225.0
Permissible tooth root stress σFP N/mm -- 225.0
Safety factor tooth root strength SF -- -- 7.73
Calcul worm shaft deflection Symbol Unit Worm Wheel
Area moment worm shaft I1 mm^4 2352140 --
Calculated deflection worm shaft fm mm 0.035 --
Permissible deflection worm shaft fmP mm 0.042 --
Safety fact worm shaft deflection Sd -- 1.21 --