Worm Gear Sets en

1
Worm gear sets

Catalogue worm gear sets and customised worm gear sets
Advanced production methods combined with years of experience in manufacturing gears and providing
customers with sound advice have made Framo Morat’s worm gear sets a byword for quality. In recent decades
Framo Morat worm gear sets have won appreciable market shares both in Germany and abroad. Besides our
catalogue worm gear sets (made to the Framo Morat standard), which we keep in stock in moderate quantities,
we also manufacture customised worm gear sets in compliance with customer specifications. Our catalogue
worm gear sets are generally available in a wide range of centre distances and transmission ratios directly from
stock. Our factory can calculate and manufacture centre distances and transmission ratios deviating from the
Framo Morat standard, although it will not always be possible to use available gear cutting tools.
The worm gear sets are usually right-handed but can be produced left-handed on request. Depending on the
transmission ratio, tooling will have to be procured first.
Pressure Angle
Due to the manufacturing process, the teeth have a K flank shape. The pressure angle is generally 15° and
therefore deviates from the DIN standard of 20°. A pressure angle of 15° allows more favourable radial force
component conditions. This reduces the bending stress of the worm shaft and the pushing away of the
associated worm gear, reducing the noise and increasing the service life. The efficiency differences due to the
modification of the pressure angle are negligible.
Metric conversion table

Our standard worm gear sets are primarily designed in metric scales. The catalog data can be converted into
'English measures' by using the following conversion table:
Metric units Factor English units

Torque (Nm) x 8.85 in.lb.
Distance (mm) x 0.03937 in.
ISO-tolerances
The worm gear drawings show ISO-tolerances like Ø32H7. If you are not familiar with ISO-tolerances please call
Framo Morat or the local distributor to get the precise dimensions.
Construction materials
The worms are made of case hardened steel with ground bore and worm profile. The worm gears are made of
a special alloy (copper-zinc alloy with additives of aluminum, silicon and manganese). Chemically this alloy
belongs to the material group of CuZn40Al2 DIN 17660 (new according to EN: CuZn37Mn3Al2PbSi-S40) but is
treated for better sliding characteristics. The chemical resistance is very high due to aluminum additives.
Mechanical characteristics:
• High corrosion resistance
• High mechanical strength:
Tensile strength Rm: 560 N/mm2
Strain limit RP0,2: 290 N/mm2
Strain at failure A5: 15%
Hardness HB2,5/62,5: 140-170
Shearing strength: 470 N/mm2
Alternating stress: 170 N/mm2 (20x106 cycles)
• Good gliding characteristics
• High wear resistance
Plastic worm gears

Plastic worm gears are suitable for low sliding speeds (< 1.5 m/s) and medium tooth pressure due to their bad
thermal conductivity. Worms have to be hardened and ground.
Plastic worm gears are suitable for 50% torque of bronze worm gears.
Mechanical characteristics: POM PA 66
Tensile strength Rm with 23°C: 70 N/mm2 50 N/mm2

D-S-TD-e3/03.16
Tensile strength Rm with 70°C: 48 N/mm2 35 N/mm2

Temperature range: -50 .... +100°C -40 .... +100°C
Subject to technical changes
Framo Morat GmbH & Co. KG Tel.: +49 (0) 7657 / 88-0 www.framo-morat.com
Franz-Morat-Straße 6 • D-79871 Eisenbach Fax: +49 (0) 7657 / 88-333 info@framo-morat.com
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Worm gear sets
The thermal expansion coefficient is appr. 4 times higher than with bronze. Therefore the backlash shouldn't be
too small. At the limit temperature of 100°C the mechanical values drop to 40% of the nominal values. The
case temperature shouldn't exceed 50°C, which means the temperature of the gears must not exceed 70°C.
Market offers a variety of different bronze for worm gears. Some of them are described here. "Soft" bronze is
good for higher speed, "hard" bronze' is good for lower speed. "Soft" bronze worm gears can be paired with
unhardened steel worms but that means reductions in torque and life time. "Hard" bronze worm gears can only
be paired with hardened steel worms.
Cu Sn 12 DIN 1705
Comparatively soft material with good wear resistance, suitable for high sliding speeds.
G-CuSn12 GZ-CuSn12 GC-CuSn12

Tensile strength Rm: 260 N/mm2 280 N/mm2 280 N/mm2
Strain limit Rp0,2: 140 N/mm2 150 N/mm2 140 N/mm2
Strain at failure A5: 12 % 5% 8%
Hardness HB10: 80 95 90
Cu Sn 12 Ni DIN 1705
Comparatively soft material with very good wear resistance, suitable for very high sliding speeds.
G-CuSn12Ni GZ-CuSn12Ni GC-CuSn12Ni

Tensile strength Rm: 280 N/mm2 300 N/mm2 300 N/mm2
Strain limit Rp0,2: 160 N/mm2 180 N/mm2 170 N/mm2
Strain at failure A5: 14 % 8% 10 %
Hardness HB10: 90 100 90
G = dead mold casting

GZ = centrifugal casting
GC = continuous casting
CuAl10Fe3 Mn2 DIN 17665 / 17672

Comparatively hard material for high torque and low speed.
CuAl10Fe3 Mn2 CuAl10Ni5F4

Tensile strength Rm: 590 N/mm2 700 N/mm2
Strain limit Rp0,2: 250 N/mm2 300 N/mm2
Strain at failure A5: 12 % 13%
Hardness HB 2,5 / 62,5: 150 160
Torque factor
The catalog torque ratings are based on 2,800 rpm worm speed. The following table shows the torque factors
for different worm speeds:
n1 2800 rpm 1400 rpm 950 rpm 700 rpm 500 rpm 250 rpm 125 rpm
Factor n1 1 1,12 1,2 1,26 1,33 1,49 1,67
Lifetime factor
The catalog torque ratings are based on 3000 hours expected lifetime. The following table shows the torque
ratings for different lifetimes:
life time appr. 3000 h appr. 1500 h appr. 6000 h
factor Lh 1 1,4 0,71
3
Worm gear sets
1. Calculation example (without consideration of the operating conditions)
worm gear set A40 U35, lubrication with mineral oil,

worm speed 700 min-1, life time 1500 h
Question: What's the expected maximum torque?
Output torque: =T2 (Mineral oil) x n1 (Factor) x Lh (Factor)
= 37,2 Nm x 1,26 x 1,4 T2 see table on page 14
= 65,6 Nm
Attention! The torque is limited by the tooth strength of the gear. The tooth strength is reached at approx.
300% of the catalog specification for synthetic oil (T2 SO).
EXAMPLE: Breaking point for A40 U35 = 46,5 Nm x 3 = 139,5 Nm.
Application factors
Due to the wide range of applications the following factors are recommendations which enable the customer to
choose the correct configuration. The case temperature shouldn't exceed 80°C.
Shocks none moderate heavy

shock factor f1 1 1,2 1,5
No. of starts 10/h 60/h 360/h

start factor f2 1 1,1 1,2
duty cycle <40 % <70 % <100 %

duty cycle factor f3 1 1,15 1,3
2. Calculation example (with consideration of the operating conditions)
worm gear set A40 Ü35; T2 = 65,6 Nm (see above), but with the following operating conditions:
- heavy shocks
- 360 starts / h
- 100 % duty cycle
T2
Output torque =
f1 x f2 x f3
65,6 Nm
=
1,5 x 1,2 x 1,3
= 28 Nm
The relationship between life time, speed and torque can be calculated by these simplified formulas
Calculation of the life time (Lh neu) with given torque (T2 neu)
2 T2 Nenn.=Output torque (catalog specification)
Lh neu = (
T2 Nenn. x Factor n1
T2 neu ) • Lh Nenn
Lh Nenn= Life time (catalog specification ca. 3000 h)
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Worm gear sets
Calculation of the torque (T2 neu) with given life time (Lhneu)
T2 Nenn. x Factor n1
T2 neu =
Lh neu
Lh Nenn
Self locking
Self-locking is affected by lead angle, surface quality, running speed, lubrication and temperature. A distinction
must be made between dynamic (from motion) and static (standstill) self-locking.
Dynamic self locking: lead angle up to 3° with grease lubrication; lead angle up to 2,5° with synthetic oil
lubrication.
Static self locking: lead angle from 3° up to 5° with grease lubrication; lead angle from 2,5° up to 4,5° with
synthetic oil lubrication.
Lead angles above 4,5° or 5° are not self locking.
Shocks or vibrations can neutralize self-locking.

A number of factors associated with lubrication, running speed and loading can favour slip characteristics to
such an extent that self-locking is counteracted.
Therefore it is impossible for us to accept warranty obligations in respect to self-locking.
Mounting of the worm gear
Use the reference surface for latheral adjustment. The latheral tolerance “c” must not
exceed 0,15 mm regardless of the center dictance.
Reference
surface
Move gear in Correct Move gear in

direction of arrow contact pattern direction of arrow
The contact pattern shows installation errors. The contact pattern should tend to the outgoing side. In case of
reversing operation the contact pattern should tend to the center of the worm gear.
Efficiency
Generally efficiency depends on the following conditions:
• lead angle of the worm,
• running speed,
• lubrication,
• surface quality,
• mounting conditions.
The efficiency increases with growing center distance. The use of plain bearings with high coefficients of friction
may affect the overall efficiency. The stated efficiency values apply for optimum mounting conditions.
Starting efficiency
The lubricating film between the flanks is not formed until the gear is running. That is the reason for a lower
starting efficiency (approx. 30% below running efficiency).
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Worm gear sets
Efficiency with driving worm gear
The efficiency with driving worm gear is smaller than with driving worm. The following formula can be used:
with: => efficiency with driving worm gear

=> efficiency with driving worm (specified in catalog)
if is negative, self locking is likely.
Customer-Specific Worm Gear Sets

Customised worm gear sets can be manufactured in compliance with customer specifications in various
versions and materials.
Framo Morat supplies customised worm gear sets in a centre distance range from 17 to 125 mm, with a max.
worm gear diameter of 200 mm. If necessary, Framo Morat calculates the toothing data, defines the materials
and surface treatment, and provides advice for lubrication and torque loads.
We use to that purpose a calculation programme based on the DIN standard. Framo Morat’s vast experience
gained all along 60 years of worm gear sets production has shown that, especially in the case of short delivery
times and small quantities, our customer mainly opt for existing gear cutting tools. The production method must
then be examined on a case-by-case basis.
Crossed helical gears

Crossed helical gears are nothing but a spur gear, which helix angle meets the lead angle of the worm. The
gliding surface is only a line. The result is reduced torque or reduced life time compared with conventional
worm gear sets.
Worm gear sets
7
Worm gear sets
ME
A17 (17 mm center distance) TR
IC
ground
center distance
Worm
Wormgear pressure angle 15°
i = gear ratio da1 = tip diameter (worm) MG = mineral grease

m= lead angle z2 = No. of teeth MO = mineral oil / synthetic grease
m = module dm2 = pitch diameter (worm gear) SO = synthetic oil
z1 = number of threads dA = max. diameter (worm gear)
dm1 = pitch diameter (worm) T2 = output torque
Catalog worm wormgear T2 [Nm]No.

Bronze Phe-
i m m z1 dm1 da1 z2 dm2 dA MG MO SO nolic
A17U2* 2.25 48°15' 0.9 8 10.15 11.95 18 23.85 25.63 1.1 1.3 1.6 0.4
A17U4 4.5 21°50' 0.75 6 12.1 13.6 27 21.9 24.6 1.7 2.0 2.6 0.7
A17U5 5 21°37' 0.7 6 11.4 12.8 30 22.6 24.6 1.8 2.2 2.7 0.7
A17U7 7 14°4' 1 3 12.34 14.34 21 21.66 24.6 1.6 1.9 2.4 0.6
A17U9 9 9°40' 0.75 3 13.4 14.9 27 20.6 22.7 1.5 1.8 2.2 0.6
A17U10 10 11°48' 0.75 3 11.0 12.5 30 23.0 24.6 1.9 2.3 2.8 0.8
A17U15 15 7°38' 0.75 2 11.3 12.8 30 22.7 24.6 1.9 2.3 2.8 0.8
A17U25 25 4°32' 0.9 1 11.4 13.2 25 22.6 24.6 1.8 2.2 2.7 0.7
A17U30 30 3°45' 0.75 1 11.45 12.95 30 22.55 24.6 1.9 2.3 2.8 0.8
A17U40 40 2°3' 0.5 1 13.98 14.98 40 20.02 21.6 1.4 1.7 2.1 0.6
A17U50** 50 3°12' 0.5 1 8.95 9.95 50 25.05 27.2 1.0 1.2 1.5 0.4
A17U60 60 2°18' 0.4 1 9.95 10.75 60 24.05 26.0 1.6 1.9 2.4 0.6
A17U75 75 1°28' 0.3 1 11.74 12.34 75 22.26 24.0 1.5 1.8 2.2 0.5
A17U80 80 1°43' 0.3 1 10.0 10.84 80 24.0 25.1 1.5 1.8 2.2 0.5
* Worm gear set A17U2 only available with polished worm profile and crossed helical gear.
** The hub diameter of the A17U50 worm is 9 mm.
All worms and worm gears stocked right hand only.

Worm made of case hardened and ground steel (HV 620 - 700).
Worm gear made of CuZn37Mn3Al2PbSi-S40 or at request of plastic or Hgw 2083. Phenolic worm gears
do not have the pre-drilled start for a pin. The outside diameter of the phenolic gear hub is 18 mm.
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Worm gear sets
ME
TR
IC
A22 (22.62 mm center distance)
ground
center distance
Worm
Wormgear
pressure angle 15°


Bronze Phe-
A22U3 3:1 17°36' 1.0 7 23.15 25.15 21 22.09 24.8 2.2 2.6 3.3 0.9
A22U4 4:1 19°32' 1.25 5 18.7 21.2 20 26.54 29.8 3.6 4.3 5.4 1.4
A22U7 7:1 11°46' 1.25 3 18.4 20.9 21 26.84 29.8 3.6 4.3 5.4 1.4
A22U11 10.5:1 7°41' 1.25 2 18.7 21.2 21 26.54 29.8 3.4 4.1 5.1 1.4
A22U21 21:1 3°48' 1.25 1 18.9 21.4 21 26.34 29.8 3.4 4.1 5.1 1.4
A22U30 30:1 2°50' 0.9 1 18.2 20 30 27.04 29.8 3.6 4.3 5.4 1.4
A22U40 40:1 2°20' 0.7 1 17.2 18.6 40 28.04 29.8 3.9 4.7 5.8 1.6

Worm gear made of CuZn37Mn3Al2PbSi-S40 or at request of plastic or Hgw 2083.
9
Worm gear sets
ME
TR
IC
A25 (25 mm center distance)
ground
center distance
Worm
Wormgear
pressure angle 15°

m= lead angle z2 = No. of theeth MO = mineral oil / synthetic grease

Bronze Phe-
A25U4 4:1 20°29' 1.4 5 20 22.8 20 30.0 33.5 5.1 6.1 7.6 2.0
A25U5 5:1 19°15' 1.5 4 18.2 21.2 20 31.8 34.8 6.5 7.8 9.7 2.6
A25U6 6.5:1 13°52' 1.15 4 19.2 21.5 26 30.8 34.8 6 7.2 9 2.4
A25U10 10:1 8°48' 1.5 2 19.6 22.6 20 30.4 34.8 5.9 7.1 8.8 2.4
A25U15 15:1 6°29' 1.0 2 17.7 19.7 30 32.3 34.8 5.7 6.8 8.5 2.3
A25U20 20:1 4°19' 1.5 1 19.9 22.9 20 30.1 34.8 5.8 7.0 8.7 2.3
A25U25 25:1 2°18' 1.0 1 24.96 26.96 25 25.04 27.8 4.1 4.9 6.1 1.6
A25U30 30:1 2°53' 1.0 1 19.9 21.9 30 30.1 33.5 5.9 7.1 8.8 2.4
A25U40 40:1 2°33' 0.8 1 17.96 19.56 40 32.04 34.8 6.2 7.4 9.3 2.5
A25U50 50:1 1°43' 0.6 1 19.96 21.16 50 30.04 33.5 5.1 6.1 7.6 2.0

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Worm gear sets
ME
TR
IC
ground
Worm
center distance
Wormgear
pressure angle 15°


Bronze Phe-
A31U2* 2.5:1 45°15' 1.25 10 17.6 20.1 25 44.4 46.9 4.4 5.3 6.6 1.7
A31U3 3:1 35°10' 1.15 10 19.97 22.27 30 42.03 44.5 4.5 5.4 6.7 1.8
A31U4 4.28:1 25°24' 1.25 7 20.4 22.9 30 41.6 45 9 10.8 13.5 3.6
A31U5 5:1 23°46' 1.3 6 19.35 21.95 30 42.65 46.5 9.5 11.4 14.2 3.8
A31U6 6:1 18°13' 1.3 5 20.8 23.4 30 41.2 45 7.6 9.1 11.4 3.0
A31U7 7:1 20°32' 1.5 4 17.1 20.1 28 44.9 48.8 9.7 11.6 14.5 3.9
A31U8 8.33:1 19°49' 1.75 3 15.5 19 25 46.5 51 10 12 15 4.0
A31U10 10:1 12°50' 1.4 3 18.9 21.7 30 43.1 47 9.5 11.4 14.2 3.8
A31U12 12:1 13°55' 1.25 3 15.6 18.1 36 46.4 50 12.1 14.5 18.1 4.8
A31U15 15:1 10°40' 1.5 2 16.2 19.2 30 45.8 50 10.7 12.8 16 4.3
A31U18/1.25 18:1 8°44' 1.25 2 16.46 18.96 36 45.54 48.8 10.3 12.4 15.4 4.1
A31U20/0.75 20:1 7°49' 0.75 3 16.54 18.04 60 45.46 48 8.3 10 12.4 3.3
A31U20/1.15 20:1 8°33' 1.15 2 15.47 17.77 40 46.53 50 10.3 12.4 15.4 4.1
A31U22 22:1 6°29' 1 2 17.7 19.7 44 44.3 48 9.6 11.5 14.4 3.8
A31U23 23:1 7°29' 2 1 15.35 19.35 23 46.65 52 10.5 12.6 15.7 4.2
A31U24 24:1 5°4' 1.75 1 19.8 23.3 24 42.2 47 9.2 11 13.8 3.7
* Worm gear set only available with polished worm profile and crossed helical gear.
All worms and worm gears stocked right hand only, worm made of case hardened and ground steel (HV 620 -
700). Worm gear made of CuZn37Mn3Al2PbSi-S40 or at request of plastic or Hgw 2083.
11
Worm gear sets
ME
TR
IC
ground
Worm
center distance
Wormgear
pressure angle 15°


Bronze Phe-
A31U25 25:1 5°35' 1.75 1 18 21.5 25 44 48.5 9.6 11.5 14.4 3.8
A31U28 28:1 4°20' 1.5 1 19.85 22.85 28 42.15 46.5 9.1 10.9 13.6 3.6
A31U30 30:1 5°7' 1.5 1 16.8 19.8 30 45.2 48.8 10.3 12.4 15.4 4.1
A31U32 32:1 4°45' 1.4 1 16.9 19.7 32 45.1 48.8 10.2 12.2 15.3 4.1
A31U38 38:1 5°1' 1.25 1 14.3 16.8 38 47.7 51.2 11.4 13.7 17.1 4.6
A31U45 45:1 3°23' 1 1 16.93 18.93 45 45.07 48 9.5 11.4 14.2 3.8
A31U50 50:1 3°3' 0.9 1 16.9 18.7 50 45.1 48 9 10.8 13.5 3.6
A31U55 55:1 4°12' 0.9 1 12.3 14.1 55 49.7 52 10.4 12.5 15.6 4.2
A31U60 60:1 2°33' 0.75 1 16.9 18.4 60 45.1 48 8.2 9.8 12.3 3.3
A31U70 70:1 3°7' 0.7 1 12.9 14.3 70 49.1 52 9 10.8 13.5 3.6
A31U75 75:1 2°2' 0.6 1 16.9 18.1 75 45.1 47 7.3 8.8 10.9 2.9
A31U90 90:1 1°41' 0.5 1 17 18 90 45 48 6.4 7.7 9.6 2.6
A31U100 100:1 2°24' 0.5 1 11.96 12.96 100 50.04 52.7 7.4 8.9 11.1 3.0
All worms and worm gears stocked right hand only, worm made of case hardened and ground steel (HV 620 -
700). Worm gear made of CuZn37Mn3Al2PbSi-S40 or at request of plastic or Hgw 2083.
12
Worm gear sets
ME
TR
IC
ground
Worm center distance
* Width tolerance of the keyway in the area of the teeth.

In the area of the collar, this can be larger due to the process. Wormgear
For proper functioning, the feather key must be provided
beneath the toothed area. pressure angle 15°


Bronze Phe-
A33U3 3.5:1 25°57' 1.75 6 24 27.5 21 42 47 10.1 12.1 15.1 4.0

A33U5 5:1 20°50' 2 4 22.5 26.5 20 43.5 49 10.6 12.7 15.9 4.2
A33U7 7:1 15°32' 1.5 4 22.4 25.4 28 43.6 48 12.2 14.6 18.3 4.9
A33U10 10:1 13°10' 1.5 3 19.75 22.75 30 46.25 51 13.3 16 19.9 5.3
A33U11 11.33:1 10°42' 1.3 3 21 23.6 34 45 49.2 13.3 16 19.9 5.3
A33U12 12:1 11°14' 1.9 2 19.5 23.3 24 46.5 52 13.5 16.2 20.2 5.4
A33U14 14:1 7°20' 1.5 2 23.5 26.5 28 42.5 47 11.4 13.7 17.1 4.6
A33U15 15:1 8°25' 1.5 2 20.5 23.5 30 45.5 50 13 15.6 19.5 5.2
A33U16 16:1 10°1' 1.5 2 17.24 20.24 32 48.76 53 14 16.8 21 5.6
A33U17 17:1 9°3' 1.4 2 17.8 20.6 34 48.2 52.5 14.2 17 21.3 5.7
A33U18 18:1 6°57' 1.25 2 20.65 23.15 36 45.35 49.2 12.6 15.1 18.9 5.0
A33U20 20:1 6°43' 1.15 2 19.66 21.96 40 46.34 50.5 12.7 15.2 19 5.1
A33U24 24:1 5°27' 1.9 1 20 23.8 24 46 51 13.2 15.8 19.8 5.3
A33U28 28:1 3°36' 1.5 1 23.9 26.9 28 42.1 46.6 11.2 13.4 16.8 4.5
A33U30 30:1 4°8' 1.5 1 20.85 23.85 30 45.15 50 12.7 15.2 19 5.1
A33U32 32:1 4°50' 1.5 1 17.8 20.8 32 48.2 52.5 13.5 16.2 20.2 5.4
A33U38 38:1 3°55' 1.25 1 18.26 20.76 38 47.74 51.6 13.9 16.7 20.8 5.6
A33U50 50:1 2°27' 0.9 1 21 22.8 50 45 48 10 12 15 4.0
A33U56 56:1 2°10' 0.8 1 21.15 22.75 56 44.85 48 10.1 12.1 15.1 4.0
A33U60 60:1 2°33' 0.8 1 17.96 19.56 60 48.04 51.5 11.4 13.7 17.1 4.6
A33U72 72:1 1°30' 0.6 1 22.8 24 72 43.2 46 8.4 1001 12.6 3.4
A33U75 75:1 1°41' 0.6 1 20.5 21.7 75 45.5 48 9 10.8 13.5 3.6
All worms and worm gears stocked right hand only, worm made of case hardened and ground steel (HV
620 - 700). Worm gear made of CuZn37Mn3Al2PbSi-S40 or at request of plastic or Hgw 2083.
13
Worm gear sets
ME
TR
IC
ground ø *
center distance
Worm
* Width tolerance of the keyway in the area of the teeth.

In the area of the collar, this can be larger due to the process. Wormgear
For proper functioning, the feather key must be provided
beneath the toothed area. pressure angle 15°

Catalog worm wormgear T2 [Nm] No.

Bronze
i m m z1 dm1 da1 z2 dm2 dA MG MO SO
A35U3* 2.78:1 31°01' 1.5 9 26.2 29.2 25 43.8 46.76 6.6 8.2 10.2
A35U5 5:1 22°52' 1.75 5 22.52 26.02 25 47.48 53 15.3 18.4 22.9
A35U7 7.25:1 13°47' 1.5 4 25.18 28.18 29 44.82 50 14.7 17.6 22
A35U8 8:1 14°25' 1.9 3 22.89 26.69 24 47.11 53 16.7 20 25
A35U10 10:1 10°43' 1.5 3 24.2 27.2 30 45.8 51 16 19.2 24
A35U11 11:1 10°32' 1.4 3 22.98 25.78 33 47.02 52 16.7 20 25
A35U12 12:1 9°11' 1.9 2 23.8 27.6 24 46.2 52 16.1 19.3 24
A35U15 15:1 7° 1.5 2 24.62 27.62 30 45.38 50 15.3 18.4 22.9
A35U20 20:1 5°33' 1.15 2 23.78 26.08 40 46.22 50.5 14.8 17.8 22.2
A35U25 25:1 4°9' 0.9 2 24.87 26.67 50 45.13 49 12.9 15.5 19.3
A35U30 30:1 3°27' 1.5 1 24.92 27.92 30 45.08 50 15 18 22.5
A35U35 35:1 3°51' 1.4 1 20.85 23.65 35 49.15 53 17.1 20.5 25.6
A35U40 40:1 2°45' 1.15 1 23.91 26.21 40 46.09 50.5 14.7 17.6 22
A35U50 50:1 2°4' 0.9 1 24.93 26.73 50 45.07 49 12.9 15.5 19.3
A35U58 58:1 2°21' 0.85 1 20.65 22.35 58 49.35 53 14.5 17.4 21.7
A35U90 90:1 1°9' 0.5 1 25 26 90 45 49 9.1 10.9 13.6
* The worm gear of the A35U3 gear set can also be delivered as a crossed helical gear, pressure angle 20°.
14
Worm gear sets
ME
TR
IC
ground
Worm
center distance
Wormgear
pressure angle 15°


Bronze
A40U7 6.75:1 21°19' 2 4 22 26 27 58 64 29.5 35.4 44.2

A40U8 8:1 16°35' 2.25 3 23.64 28.14 24 56.36 62.5 27.5 33 41.2
A40U10 10:1 16°1' 1.9 3 20.66 24.46 30 59.34 65 29.5 35.4 44.2
A40U12 12:1 10°21' 1.5 3 25.05 28.05 36 54.95 60 25.2 30.2 37.8
A40U15 15:1 9°53' 1.9 2 22.14 25.94 30 57.86 64 28 33.6 42
A40U20 20:1 8°59' 1.5 2 19.2 22.2 40 60.8 66 28.9 34.6 43.3
A40U25 25:1 5°58' 1.15 2 22.15 24.45 50 57.85 62 24.4 29.2 36.6
A40U28 28:1 4°47' 2 1 24 28 28 56 61.5 28.4 34 42.6
A40U30 30:1 5°50' 2 1 19.68 23.68 30 60.32 66 30.1 36.1 45.1
A40U35 35:1 5°26' 1.75 1 18.48 21.98 35 61.52 67 31 37.2 46.5
A40U36 36:1 3°19 1.5 1 25.91 28.91 36 54.09 59 23.9 28.6 35.8
A40U40 40:1 4°20' 1.5 1 19.83 22.83 40 60.17 65 28.3 33.9 42.4
A40U50 50:1 4°8' 1.25 1 17.3 19.8 50 62.7 68 27 32.4 40.5
A40U56 56:1 2°23' 1 1 24 26 56 56 59 21.9 26.2 32.8
A40U60 60:1 1°59' 0.9 1 25.92 27.72 60 54.08 57.5 19.3 23.1 28.9
A40U70 70:1 3°3' 0.9 1 16.91 18.71 70 63.09 67 24.1 28.9 36.1
A40U75 75:1 1°48' 0.75 1 23.75 25.25 75 56.26 60 18.8 22.5 28.2
A40U80 80:1 2°10' 0.75 1 19.9 21.4 80 60.1 64 20.1 24.1 30.1
A40U90 90:1 2°22’ 0.7 1 16.95 18.35 90 63.05 67 19.1 22.9 28.6
15
Worm gear sets
ME
TR
IC
ground
Worm
center distance
Wormgear
pressure angle 15°


Bronze
A50U4 4.25:1 25°51' 3.5 4 32.1 39.1 17 67.9 77 34 40.8 51

A50U6 6:1 19°17' 3.5 3 31.8 38.8 18 68.2 77 52 62.4 78
A50U9 8.66:1 13°52' 2.5 3 31.29 36.29 26 68.71 77 64.3 77.1 96.4
A50U12 12:1 10°23' 2.75 2 30.5 36 24 69.5 77 66.4 79.6 99.6
A50U14 13.5:1 9°38' 2.5 2 29.9 34.9 27 70.1 77 62.8 75.4 94.2
A50U19 19:1 6°17' 3.5 1 32 39 19 68 77 78.2 93.8 117.3
A50U23 23:1 5°38' 3 1 30.58 36.58 23 69.42 77 71.1 85.3 106.6
A50U27 27:1 4°40' 2.5 1 30.73 35.73 27 69.27 77 64.5 77.4 96.7
A50U35 35:1 3°51' 2 1 29.78 33.78 35 70.22 77 56.7 68 85
A50U46 46:1 2°47' 1.5 1 30.85 33.85 46 69.15 74 50.6 60.7 75.9
A50U55 55:1 2°19' 1.25 1 30.9 33.4 55 69.1 74 46.2 55.4 69.3
A50U69 69:1 1°51' 1 1 30.9 32.9 69 69.1 74 41.4 49.6 62.8
16
Worm gear sets
ME
TR
IC
hardened
hardened
ground
Worm
center distance
Wormgear
pressure angle 15°

m= lead angle z2 = No. of teeth MO = mineral oil / synthetic
m = module dm2 = pitch diameter (worm gear) grease
z1 = number of threads dA = max. diameter (worm gear) SO = synthetic oil

Bronze
A50U4 4.25:1 25°51' 3.5 4 32.1 39.1 17 67.9 77 34 40.8 51

A50U6 6:1 19°17' 3.5 3 31.8 38.8 18 68.2 77 52 62.4 78
A50U9 8.66:1 13°52' 2.5 3 31.29 36.29 26 68.71 77 64.3 77.1 96.4
A50U12 12:1 10°23' 2.75 2 30.5 36 24 69.5 77 66.4 79.6 99.6
A50U14 13.5:1 9°38' 2.5 2 29.9 34.9 27 70.1 77 62.8 75.4 94.2
A50U19 19:1 6°17' 3.5 1 32 39 19 68 77 78.2 93.8 117.3
A50U23 23:1 5°38' 3 1 30.58 36.58 23 69.42 77 71.1 85.3 106.6
A50U27 27:1 4°40' 2.5 1 30.73 35.73 27 69.27 77 64.5 77.4 96.7
A50U35 35:1 3°51' 2 1 29.78 33.78 35 70.22 77 56.7 68 85
A50U46 46:1 2°47' 1.5 1 30.85 33.85 46 69.15 74 50.6 60.7 75.9
A50U55 55:1 2°19' 1.25 1 30.9 33.4 55 69.1 74 46.2 55.4 69.3
A50U69 69:1 1°51' 1 1 30.9 32.9 69 69.1 74 41.4 49.6 62.8
620 - 700), shafts not hardened. Worm gear made of CuZn37Mn3Al2PbSi-S40 or at request of plastic or
Hgw 2083.
17
Worm gear sets
ME
TR
IC
ground
Worm
center distance
Wormgear
pressure angle 15°


Bronze
A53U5 4.75:1 25°51' 3.5 4 32.1 39.1 19 73.9 83 45 54 67.5

A53U7 6.67:1 19°17' 3.5 3 31.8 38.8 20 74.2 84 67 81 101
A53U10 9.67:1 13°52' 2.5 3 31.29 36.29 29 74.71 82 77 93 116
A53U14 13.5:1 10°23' 2.75 2 30.5 36 27 75.5 84 80 96 120
A53U15 15:1 9°38' 2.5 2 29.9 34.9 30 76.1 83 75 90 113
A53U21 21:1 6°17' 3.5 1 32 39 21 74 83 94 113 141
A53U25 25:1 5°38' 3 1 30.58 36.58 25 75.42 84 84 101 127
A53U28 28:1 3°59' 2.5 1 36 41 28 70 77.5 87 104 130
A53U30 30:1 4°40' 2.5 1 30.73 35.73 30 75.27 83 77 93 116
A53U38 38:1 3°51' 2 1 29.78 33.78 38 76.21 83 68 81 102
A53U50 50:1 2°47' 1.5 1 30.85 33.85 50 75.15 81 60 72 90
A53U60 60:1 2°19' 1.25 1 30.9 33.4 60 75.1 80 55 66 82
A53U75 75:1 1°51' 1 1 30.9 32.9 75 75.1 78 49 59 74
18
Worm gear sets
ME
TR
IC
ground
Worm
center distance
Wormgear
pressure angle 15°
i = gear ratio da1 = tip diameter (worm) MO = mineral oil / synthetic grease
m= lead angle z2 = No. of teeth SO = synthetic oil
m = module dm2 = pitch diameter (worm gear)
MG = mineral grease

Bronze
A63U6 6:1 25°51' 3.5 4 32.1 39.1 24 93.9 104 89 107 134
A63U12 12:1 13°52' 2.5 3 31.29 36.29 36 94.71 104 141 170 212
A63U19 19:1 10°8' 2.5 2 28.4 33.4 38 97.6 104 133 159 199
A63U26 26:1 6°17’ 3.5 1 32 39 26 94 104 172 206 258
A63U34 34:1 5°9' 2.75 1 30.6 36.1 34 95.4 104 148 178 222
A63U48 48:1 3°51' 2 1 29.78 33.78 48 96.22 104 125 150 187
A63U63 63:1 2°47' 1.5 1 30.85 33.85 63 95.15 101 111 133 166
A63U70 70:1 1°59 1.25 1 36.1 38.6 70 89.9 97 112 135 169
19
Worm gear sets
ME
TR
IC
hardened
hardened
ground
Worm
center distance
Wormgear pressure angle 15°

m= lead angle z2 = No. of teeth MO = mineral oil / synthetic
m = module dm2 = pitch diameter (worm gear) grease
z1 = number of threads dA = max. diameter (worm gear) SO = synthetic oil

Bronze
A63U6 6:1 25°51' 3.5 4 32.1 39.1 24 93.9 104 89 107 134
A63U12 12:1 13°52' 2.5 3 31.29 36.29 36 94.71 104 141 170 212
A63U19 19:1 10°8' 2.5 2 28.4 33.4 38 97.6 104 133 159 199
A63U26 26:1 6°17’ 3.5 1 32 39 26 94 104 172 206 258
A63U34 34:1 5°9' 2.75 1 30.6 36.1 34 95.4 104 148 178 222
A63U48 48:1 3°51' 2 1 29.78 33.78 48 96.22 104 125 150 187
A63U63 63:1 2°47' 1.5 1 30.85 33.85 63 95.15 101 111 133 166
A63U70 70:1 1°59 1.25 1 36.1 38.6 70 89.9 97 112 135 169
620 - 700), shafts not hardened. Worm gear made of CuZn37Mn3Al2PbSi-S40 or at request of plastic or
Hgw 2083.
20
Worm gear sets
ME
TR
I C
ground
Worm
center distance
Wormgear
pressure angle 15°


Bronze
A65U6 6.25:1 25°51' 3.5 4 32.1 39.1 25 97.9 108 101 121 151
A65U13 12.66:1 13°52' 2.5 3 31.29 36.29 38 98.71 108 156 187 234
A65U20 20:1 10°8' 2.5 2 28.4 33.4 40 101.6 108 146 176 220
A65U28 28:1 6°17’ 3.5 1 32 39 28 98 108 192 230 288
A65U36 36:1 5°9' 2.75 1 30.6 36.1 36 99.4 108 164 197 246
A65U50 50:1 3°51' 2 1 29.78 33.78 50 100.22 108 137 164 205
A65U66 66:1 2°47' 1.5 1 30.85 33.85 66 99.15 107 122 146 183
A65U75 75:1 1°59' 1.25 1 36.1 38.6 75 93.9 100 125 150 188
21
Worm gear sets
ME
TR
IC
ground
Worm
center distance
Wormgear
pressure angle 15°
i = gear ratio da1 = tip diameter (worm) MO = mineral oil / synthetic grease
m= lead angle z2 = No. of teeth SO = synthetic oil
m = module dm2 = pitch diameter (worm gear)
MG = mineral grease

Bronze
A80U7 6.75:1 23°35' 4 4 40 48 27 120 132 150 180 225

A80U12 12:1 16°36' 2.5 4 35 40 48 125 132,5 243 290 365
A80U20 20:1 8°58' 3 2 38.5 44.5 40 121.5 130,5 290 348 435
A80U30 30:1 5°44' 4 1 40 48 30 120 132,5 348 417 522
A80U50 50:1 4°6' 2.5 1 35 40 50 125 132,5 248 297 372
A80U80 80:1 2°9' 1.5 1 40 43 80 120 124,5 213 255 320
22
Worm gear sets
ME
TR
IC
hardened
hardened
ground
Worm
center distance
Wormgear
pressure angle 15°


Bronze
A80U7 6.75:1 23°35' 4 4 40 48 27 120 132 150 180 225

A80U12 12:1 16°36' 2.5 4 35 40 48 125 132,5 243 290 365
A80U20 20:1 8°58' 3 2 38.5 44.5 40 121.5 130,5 290 348 435
A80U30 30:1 5°44' 4 1 40 48 30 120 132,5 348 417 522
A80U50 50:1 4°6' 2.5 1 35 40 50 125 132,5 248 297 372
A80U80 80:1 2°9' 1.5 1 40 43 80 120 124,5 213 255 320
620 - 700), shafts not hardened.
23
Worm gear sets
Efficiency factors
Efficiency factors depending on input (worm) speed and lubrication (mineral grease 'MG', mineral oil 'MO' or
synthetic grease, synthetic oil 'SO')
A17
n1 = 2800 rpm n1 = 1400 rpm n1 = 950 rpm n1 = 700 rpm n1 = 500 rpm
MG MO SO MG MO SO MG MO SO MG MO SO MG MO SO
U2 0,8 0,84 0,87 0,77 0,81 0,85 0,76 0,8 0,84 0,76 0,8 0,84 0,76 0,8 0,84
U4 0,75 0,79 0,83 0,72 0,76 0,8 0,7 0,75 0,79 0,7 0,74 0,79 0,7 0,74 0,79
U5 0,74 0,79 0,82 0,71 0,76 0,8 0,7 0,75 0,79 0,69 0,74 0,79 0,69 0,74 0,79
U7 0,68 0,73 0,77 0,64 0,7 0,75 0,63 0,68 0,73 0,62 0,68 0,73 0,62 0,68 0,73
U9 0,61 0,66 0,71 0,57 0,63 0,68 0,55 0,61 0,66 0,54 0,6 0,66 0,54 0,6 0,66
U10 0,64 0,69 0,74 0,6 0,66 0,71 0,59 0,65 0,7 0,59 0,64 0,7 0,59 0,64 0,7
U15 0,54 0,6 0,65 0,51 0,57 0,62 0,49 0,55 0,61 0,49 0,55 0,61 0,49 0,55 0,61
U25 0,42 0,48 0,53 0,38 0,44 0,5 0,37 0,43 0,48 0,37 0,42 0,48 0,37 0,42 0,48
U30 0,37 0,43 0,49 0,34 0,4 0,45 0,33 0,38 0,44 0,33 0,38 0,44 0,33 0,38 0,44
U40 0,26 0,3 0,36 0,23 0,27 0,32 0,22 0,26 0,31 0,21 0,25 0,3 0,21 0,25 0,3
U50 0,33 0,38 0,44 0,3 0,35 0,41 0,29 0,34 0,4 0,29 0,34 0,4 0,29 0,34 0,4
U60 0,26 0,31 0,36 0,24 0,28 0,33 0,23 0,27 0,32 0,23 0,27 0,32 0,23 0,27 0,32
U75 0,19 0,23 0,27 0,17 0,21 0,25 0,16 0,2 0,24 0,16 0,19 0,23 0,16 0,19 0,23
U80 0,21 0,25 0,3 0,19 0,23 0,27 0,18 0,22 0,26 0,18 0,22 0,26 0,18 0,22 0,26
A22
U3 0,74 0,79 0,82 0,71 0,76 0,8 0,69 0,74 0,79 0,68 0,73 0,78 0,67 0,72 0,77
U4 0,75 0,79 0,83 0,72 0,76 0,8 0,7 0,75 0,79 0,69 0,74 0,78 0,68 0,73 0,77
U7 0,66 0,71 0,76 0,63 0,68 0,73 0,61 0,66 0,71 0,6 0,65 0,7 0,59 0,64 0,69
U10,5 0,57 0,63 0,68 0,53 0,59 0,65 0,51 0,57 0,63 0,5 0,56 0,62 0,49 0,55 0,61
U21 0,4 0,46 0,52 0,37 0,42 0,48 0,35 0,4 0,46 0,34 0,39 0,45 0,33 0,38 0,44
U30 0,34 0,39 0,45 0,3 0,35 0,41 0,29 0,34 0,39 0,27 0,32 0,38 0,27 0,32 0,37
U40 0,29 0,34 o,4 0,26 0,31 0,36 0,25 0,29 0,34 0,24 0,28 0,33 0,23 0,28 0,33
A25
U4 0,76 0,8 0,84 0,73 0,77 0,81 0,71 0,76 0,8 0,7 0,75 0,79 0,69 0,74 0,78
U5 0,75 0,79 0,83 0,71 0,76 0,8 0,7 0,75 0,79 0,69 0,74 0,78 0,68 0,73 0,77
U6,5 0,7 0,74 0,79 0,66 0,71 0,76 0,64 0,7 0,75 0,63 0,68 0,73 0,62 0,67 0,72
U10 0,61 0,66 0,71 0,57 0,62 0,68 0,55 0,61 0,66 0,53 0,59 0,65 0,52 0,58 0,64
U15 0,53 0,59 0,64 0,49 0,55 0,61 0,47 0,53 0,59 0,46 0,52 0,58 0,45 0,51 0,57
U20 0,44 0,5 0,55 0,4 0,46 0,51 0,38 0,44 0,5 0,37 0,42 0,48 0,36 0,41 0,47
U25 0,3 0,36 0,41 0,27 0,32 0,38 0,26 0,3 0,35 0,25 0,29 0,34 0,23 0,28 0,33
U30 0,34 0,4 0,46 0,31 0,36 0,42 0,29 0,34 0,4 0,28 0,33 0,38 0,27 0,32 0,37
U40 0,31 0,36 0,42 0,28 0,33 0,38 0,26 0,31 0,37 0,25 0,3 0,35 0,25 0,29 0,35
U50 0,24 0,28 0,33 0,21 0,25 0,3 0,2 0,24 0,28 0,19 0,23 0,27 0,18 0,22 0,26
The stated values are approximate values
24
Worm gear sets
Operative efficiency
A31
U2,5 0,82 0,85 0,88 0,79 0,83 0,86 0,78 0,82 0,85 0,77 0,81 0,85 0,76 0,8 0,84
U3 0,81 0,85 0,87 0,78 0,82 0,86 0,77 0,81 0,85 0,76 0,8 0,84 0,75 0,79 0,83
U4,28 0,79 0,82 0,86 0,76 0,8 0,83 0,74 0,78 0,82 0,73 0,77 0,81 0,72 0,76 0,81
U5 0,78 0,82 0,85 0,75 0,79 0,83 0,73 0,78 0,82 0,72 0,77 0,81 0,71 0,76 0,8
U6 0,74 0,79 0,82 0,71 0,76 0,8 0,7 0,74 0,79 0,68 0,73 0,78 0,67 0,72 0,77
U7 0,75 0,79 0,83 0,72 0,77 0,81 0,71 0,75 0,8 0,69 0,74 0,79 0,69 0,74 0,78
U8,33 0,74 0,79 0,82 0,71 0,76 0,8 0,7 0,75 0,79 0,69 0,74 0,78 0,68 0,73 0,78
U12 0,69 0,74 0,78 0,65 0,7 0,75 0,64 0,69 0,74 0,62 0,68 0,73 0,62 0,67 0,72
U15 0,64 0,69 0,74 0,6 0,66 0,71 0,58 0,64 0,69 0,57 0,63 0,68 0,56 0,62 0,68
U18 0,59 0,65 0,7 0,56 0,61 0,67 0,54 0,6 0,65 0,53 0,58 0,64 0,52 0,58 0,63
U20 * 0,57 0,63 0,68 0,53 0,59 0,64 0,51 0,57 0,63 0,5 0,56 0,62 0,49 0,55 0,61
U20 ** 0,59 0,64 0,69 0,55 0,61 0,66 0,53 0,59 0,64 0,52 0,58 0,63 0,51 0,57 0,63
U22 0,53 0,59 0,64 0,49 0,55 0,61 0,47 0,53 0,59 0,46 0,52 0,58 0,45 0,51 0,57
U23 0,56 0,61 0,67 0,52 0,58 0,63 0,5 0,56 0,61 0,49 0,55 0,6 0,48 0,54 0,6
U24 0,48 0,54 0,59 0,44 0,49 0,55 0,42 0,48 0,54 0,4 0,46 0,52 0,39 0,45 0,51
U25 0,49 0,55 0,61 0,45 0,51 0,57 0,44 0,5 0,55 0,42 0,48 0,54 0,41 0,47 0,53
U28 0,44 0,5 0,56 0,4 0,46 0,51 0,38 0,44 0,5 0,37 0,42 0,48 0,36 0,41 0,47
U30 0,47 0,53 0,59 0,43 0,49 0,55 0,41 0,47 0,53 0,4 0,46 0,52 0,39 0,45 0,51
U32 0,45 0,51 0,57 0,41 0,47 0,53 0,4 0,45 0,51 0,38 0,44 0,5 0,38 0,43 0,49
U38 0,46 0,52 0,57 0,42 0,48 0,54 0,4 0,46 0,52 0,39 0,45 0,51 0,39 0,45 0,51
U45 0,37 0,43 0,49 0,34 0,39 0,45 0,32 0,37 0,43 0,31 0,36 0,42 0,3 0,36 0,41
U50 0,35 0,4 0,46 0,31 0,37 0,42 0,3 0,35 0,4 0,29 0,34 0,39 0,28 0,33 0,39
U55 0,4 0,46 0,52 0,37 0,43 0,48 0,36 0,41 0,47 0,35 0,41 0,46 0,35 0,41 0,46
U60 0,31 0,36 0,42 0,28 0,32 0,38 0,26 0,31 0,36 0,25 0,3 0,35 0,25 0,29 0,34
U70 0,34 0,39 0,45 0,31 0,36 0,41 0,29 0,34 0,4 0,29 0,34 0,39 0,29 0,34 0,39
U75 0,26 0,31 0,36 0,23 0,28 0,33 0,22 0,26 0,31 0,21 0,25 0,3 0,21 0,25 0,3
U90 0,23 0,27 0,32 0,2 0,24 029 0,19 0,23 0,27 0,18 0,22 0,26 0,18 0,22 0,26
U100 0,28 0,33 0,38 0,25 0,3 0,35 0,24 0,29 0,34 0,24 0,28 0,33 0,24 0,28 0,33
* module m = 0,75
** module m = 1,15
25
Worm gear sets
A33
U3,5 0,79 0,83 0,86 0,77 0,81 0,84 0,75 0,79 0,83 0,74 0,78 0,82 0,72 0,77 0,81
U5 0,77 0,81 0,84 0,74 0,78 0,82 0,72 0,76 0,81 0,71 0,75 0,8 0,69 0,74 0,79
U7 0,72 0,77 0,81 0,69 0,74 0,78 0,67 0,72 0,77 0,66 0,71 0,76 0,65 0,7 0,75
U10 0,69 0,74 0,78 0,65 0,7 0,75 0,64 0,69 0,74 0,62 0,68 0,73 0,61 0,67 0,72
U11 0,65 0,7 0,75 0,61 0,67 0,72 0,6 0,65 0,7 0,58 0,64 0,69 0,57 0,63 0,68
U12 0,66 0,71 0,75 0,62 0,67 0,72 0,6 0,66 0,71 0,59 0,64 0,7 0,58 0,63 0,69
U14 0,57 0,63 0,68 0,53 0,59 0,65 0,51 0,57 0,63 0,5 0,56 0,62 0,49 0,54 0,6
U15 0,6 0,65 0,7 0,56 0,62 0,67 0,54 0,6 0,65 0,53 0,58 0,64 0,51 0,57 0,63
U16 0,63 0,68 0,73 0,59 0,64 0,7 0,57 0,63 0,68 0,56 0,62 0,67 0,55 0,61 0,66
U17 0,61 0,66 0,71 0,57 0,62 0,68 0,55 0,61 0,66 0,54 0,6 0,65 0,53 0,59 0,64
U18 0,55 0,61 0,67 0,51 0,57 0,63 0,5 0,55 0,61 0,48 0,54 0,6 0,47 0,53 0,59
U20 0,54 0,6 0,66 0,5 0,56 0,62 0,49 0,54 0,6 0,47 0,53 0,59 0,46 0,52 0,58
U24 0,49 0,55 0,61 0,45 0,51 0,57 0,44 0,5 0,55 0,42 0,48 0,54 0,41 0,47 0,53
U28 0,4 0,46 0,52 0,37 0,42 0,48 0,35 0,4 0,46 0,33 0,39 0,45 0,32 0,38 0,43
U30 0,43 0,49 0,55 0,39 0,45 0,51 0,37 0,43 0,49 0,36 0,42 0,47 0,35 0,4 0,46
U32 0,46 0,52 0,58 0,42 0,48 0,54 0,4 0,46 0,52 0,39 0,45 0,51 0,38 0,44 0,5
U38 0,41 0,47 0,53 0,37 0,43 0,49 0,36 0,41 0,47 0,34 0,4 0,46 0,33 0,39 0,45
U50 0,31 0,36 0,42 0,28 0,33 0,38 0,26 0,31 0,38 0,25 0,3 0,35 0,24 0,29 0,34
U56 0,29 0,34 0,39 0,25 0,3 0,35 0,24 0,29 0,34 0,23 0,27 0,32 0,22 0,26 0,31
U60 0,31 0,36 0,42 0,28 0,33 0,38 0,26 0,31 0,37 0,25 0,3 0,35 0,25 0,29 0,35
U72 0,22 0,26 0,31 0,19 0,23 0,28 0,18 0,22 0,26 0,17 0,21 0,25 0,17 0,2 0,24
U75 0,24 0,28 0,33 0,21 0,25 0,29 0,2 0,24 0,28 0,19 0,23 0,27 0,18 0,22 0,26
A35
U2,78 0,81 0,85 0,87 0,79 0,83 0,86 0,77 0,81 0,84 0,76 0,8 0,84 0,75 0,79 0,83
U5 0,78 0,82 0,85 0,75 0,79 0,83 0,73 0,78 0,82 0,72 0,77 0,81 0,71 0,76 0,8
U7,25 0,71 0,75 0,8 0,68 0,73 0,77 0,65 0,71 0,75 0,64 0,69 0,74 0,63 0,68 0,73
U8 0,71 0,76 0,8 0,68 0,73 0,77 0,66 0,71 0,76 0,65 0,7 0,75 0,63 0,69 0,74
U10 0,66 0,71 0,76 0,62 0,68 0,73 0,6 0,66 0,71 0,59 0,64 0,7 0,57 0,63 0,68
U11 0,65 0,7 0,75 0,62 0,67 0,72 0,6 0,65 0,7 0,58 0,64 0,69 0,57 0,63 0,68
U12 0,63 0,68 0,73 0,59 0,64 0,7 0,57 0,62 0,68 0,55 0,61 0,66 0,54 0,6 0,65
U15 0,57 0,62 0,68 0,53 0,59 0,64 0,5 0,56 0,62 0,49 0,55 0,61 0,48 0,54 0,59
U20 0,51 0,57 0,62 0,47 0,53 0,59 0,45 0,51 0,56 0,43 0,49 0,55 0,42 0,48 0,54
U25 0,44 0,5 0,56 0,4 0,46 0,52 0,38 0,44 0,5 0,37 0,42 0,48 0,35 0,41 0,47
U30 0,4 0,45 0,51 0,36 0,42 0,47 0,34 0,39 0,45 0,33 0,38 0,44 0,31 0,37 0,42
U35 0,41 0,47 0,53 0,37 0,43 0,49 0,36 0,41 0,47 0,34 0,4 0,46 0,33 0,39 0,44
U40 0,34 0,4 0,45 0,31 0,36 0,42 0,29 0,34 0,4 0,28 0,33 0,38 0,27 0,32 0,37
U50 0,28 0,33 0,39 0,25 0,3 0,35 0,24 0,28 0,33 0,23 0,27 0,32 0,22 0,26 0,31
U58 0,3 0,35 0,41 0,27 0,32 0,37 0,26 0,3 0,35 0,24 0,29 0,34 0,24 0,28 0,33
U90 0,18 0,22 0,26 0,16 0,19 0,23 0,15 0,18 0,22 0,14 0,17 0,21 0,13 0,16 0,2
26
Worm gear sets
A40
U6,75 0,77 0,81 0,84 0,74 0,78 0,82 0,72 0,77 0,81 0,71 0,76 0,8 0,7 0,75 0,79
U8 0,74 0,78 0,82 0,7 0,75 0,79 0,68 0,73 0,78 0,67 0,72 0,77 0,66 0,71 0,76
U10 0,72 0,77 0,81 0,69 0,74 0,78 0,67 0,72 0,77 0,66 0,71 0,76 0,65 0,7 0,75
U12 0,65 0,7 0,75 0,62 0,67 0,72 0,6 0,65 0,7 0,58 0,64 0,69 0,57 0,62 0,68
U15 0,64 0,69 0,74 0,6 0,65 0,71 0,58 0,64 0,69 0,57 0,62 0,68 0,55 0,61 0,66
U20 0,61 0,66 0,71 0,57 0,63 0,68 0,55 0,61 0,66 0,54 0,6 0,65 0,53 0,59 0,64
U25 0,52 0,58 0,64 0,48 0,54 0,6 0,46 0,52 0,58 0,45 0,51 0,56 0,43 0,49 0,55
U28 0,47 0,53 0,59 0,43 0,49 0,55 0,41 0,47 0,53 0,4 0,46 0,52 0,39 0,44 0,5
U30 0,51 0,57 0,62 0,47 0,53 0,59 0,45 0,51 0,57 0,44 0,5 0,55 0,43 0,48 0,54
U35 0,49 0,55 0,6 0,45 0,51 0,57 0,43 0,49 0,55 0,42 0,48 0,54 0,41 0,47 0,53
U36 0,39 0,45 0,5 0,35 0,41 0,47 0,33 0,39 0,44 0,32 0,37 0,43 0,31 0,36 0,42
U38 0,41 0,47 0,53 0,37 0,43 0,49 0,36 0,41 0,47 0,34 0,4 0,45 0,33 0,38 0,44
U40 0,44 0,5 0,56 0,4 0,46 0,52 0,38 0,44 0,5 0,37 0,43 0,48 0,36 0,41 0,47
U50 0,42 0,48 0,54 0,38 0,44 0,5 0,37 0,42 0,48 0,35 0,41 0,47 0,35 0,4 0,46
U56 0,31 0,36 0,42 0,28 0,33 0,38 0,26 0,31 0,36 0,25 0,3 0,35 0,24 0,29 0,34
U60 0,28 0,33 0,38 0,25 0,29 0,34 0,23 0,28 0,32 0,22 0,26 0,31 0,21 0,25 0,3
U70 0,35 0,4 0,46 0,31 0,37 0,42 0,3 0,35 0,4 0,29 0,34 0,39 0,28 0,33 0,39
U75 0,25 0,3 0,35 0,23 0,27 0,32 0,21 0,25 0,3 0,2 0,24 0,29 0,19 0,23 0,28
U80 0,28 0,33 0,39 0,25 0,3 0,35 0,24 0,28 0,33 0,23 0,27 0,32 0,22 0,26 0,31
U90 0,29 0,34 0,4 0,36 0,31 0,36 0,25 0,29 0,35 0,24 0,28 0,33 0,23 0,28 0,33
A50
U4,25 0,8 0,84 0,87 0,78 0,82 0,85 0,76 0,8 0,84 0,75 0,79 0,83 0,74 0,78 0,82
U6 0,77 0,81 0,84 0,74 0,78 0,82 0,72 0,77 0,81 0,71 0,76 0,8 0,7 0,74 0,79
U8 0,72 0,76 0,8 0,69 0,74 0,78 0,67 0,72 0,76 0,65 0,7 0,75 0,64 0,69 0,74
U12 0,66 0,71 0,76 0,63 0,68 0,73 0,61 0,66 0,71 0,59 0,65 0,7 0,58 0,63 0,69
U13,5 0,65 0,7 0,74 0,61 0,67 0,72 0,59 0,64 0,7 0,57 0,63 0,68 0,56 0,62 0,67
U19 0,55 0,61 0,66 0,52 0,57 0,63 0,49 0,55 0,61 0,48 0,54 0,59 0,46 0,52 0,58
U23 0,52 0,58 0,64 0,49 0,55 0,6 0,46 0,52 0,58 0,45 0,51 0,57 0,43 0,49 0,55
U27 0,48 0,54 0,59 0,44 0,5 0,56 0,42 0,48 0,54 0,4 0,46 0,52 0,39 0,45 0,51
U35 0,43 0,49 0,55 0,4 0,45 0,51 0,37 0,43 0,49 0,36 0,41 0,47 0,34 0,4 0,46
U46 0,36 0,41 0,47 0,32 0,38 0,43 0,3 0,36 0,41 0,29 0,34 0,4 0,28 0,33 0,38
U55 0,31 0,37 0,42 0,29 0,34 0,39 0,27 0,31 0,37 0,25 0,3 0,35 0,24 0,29 0,34
U69 0,27 0,32 0,37 0,24 0,29 0,34 0,23 0,27 0,32 0,21 0,26 0,3 0,2 0,25 0,29
27
Worm gear sets
A53
U4,75 0,8 0,84 0,87 0,78 0,82 0,85 0,76 0,8 0,84 0,75 0,79 0,83 0,74 0,78 0,82
U6,67 0,77 0,81 0,84 0,74 0,78 0,82 0,72 0,77 0,81 0,71 0,76 0,8 0,7 0,74 0,79
U9,67 0,72 0,76 0,8 0,69 0,74 0,78 0,67 0,72 0,76 0,65 0,7 0,75 0,64 0,69 0,74
U13,5 0,66 0,71 0,76 0,63 0,68 0,73 0,61 0,66 0,71 0,59 0,65 0,7 0,58 0,63 0,69
U15 0,65 0,7 0,74 0,61 0,67 0,72 0,59 0,64 0,7 0,57 0,63 0,68 0,56 0,62 0,67
U21 0,55 0,61 0,66 0,52 0,57 0,63 0,49 0,55 0,61 0,48 0,54 0,59 0,46 0,52 0,58
U25 0,52 0,58 0,64 0,49 0,55 0,6 0,46 0,52 0,58 0,45 0,51 0,57 0,43 0,49 0,55
U28 0,44 0,5 0,56 0,41 0,47 0,53 0,39 0,45 0,51 0,37 0,43 0,49 0,36 0,42 0,47
U30 0,48 0,54 0,59 0,44 0,5 0,56 0,42 0,48 0,54 0,4 0,46 0,52 0,39 0,45 0,51
U38 0,43 0,49 0,55 0,4 0,45 0,51 0,37 0,43 0,49 0,36 0,41 0,47 0,34 0,4 0,46
U50 0,36 0,41 0,47 0,32 0,38 0,43 0,3 0,36 0,41 0,29 0,34 0,4 0,28 0,33 0,38
U60 0,31 0,37 0,42 0,29 0,34 0,39 0,27 0,31 0,37 0,25 0,3 0,35 0,24 0,29 0,34
U75 0,27 0,32 0,37 0,24 0,29 0,34 0,23 0,27 0,32 0,21 0,26 0,3 0,2 0,25 0,29
A63
U6 0,8 0,84 0,87 0,78 0,82 0,85 0,76 0,8 0,84 0,75 0,79 0,83 0,74 0,78 0,82
U12 0,72 0,76 0,8 0,69 0,74 0,78 0,67 0,72 0,76 0,65 0,7 0,75 0,64 0,69 0,74
U19 0,65 0,71 0,75 0,62 0,67 0,72 0,6 0,65 0,7 0,58 0,64 0,69 0,57 0,62 0,68
U26 0,55 0,61 0,66 0,52 0,57 0,63 0,49 0,55 0,61 0,48 0,54 0,59 0,46 0,52 0,58
U34 0,5 0,56 0,62 0,47 0,53 0,58 0,44 0,5 0,56 0,43 0,49 0,54 0,41 0,47 0,53
U48 0,43 0,49 0,55 0,4 0,45 0,51 0,37 0,43 0,49 0,36 0,41 0,47 0,34 0,4 0,46
U63 0,36 0,41 0,47 0,32 0,38 0,43 0,3 0,36 0,41 0,29 0,34 0,4 0,28 0,33 0,38
U70 0,29 0,34 0,39 0,26 0,31 0,36 0,24 0,29 0,34 0,23 0,28 0,32 0,22 0,26 0,3
28
Worm gear sets
A65
U6,25 0,8 0,84 0,87 0,78 0,82 0,85 0,76 0,8 0,84 0,75 0,79 0,83 0,74 0,78 0,82
U12,66 0,72 0,76 0,8 0,69 0,74 0,78 0,67 0,72 0,76 0,65 0,7 0,75 0,64 0,69 0,74
U20 0,65 0,71 0,75 0,62 0,67 0,72 0,6 0,65 0,7 0,58 0,64 0,69 0,57 0,62 0,68
U28 0,55 0,61 0,66 0,52 0,57 0,63 0,49 0,55 0,61 0,48 0,54 0,59 0,46 0,52 0,58
U36 0,5 0,56 0,62 0,47 0,53 0,58 0,44 0,5 0,56 0,43 0,49 0,54 0,41 0,47 0,53
U50 0,43 0,49 0,55 0,4 0,45 0,51 0,37 0,43 0,49 0,36 0,41 0,47 0,34 0,4 0,46
U66 0,36 0,41 0,47 0,32 0,38 0,43 0,3 0,36 0,41 0,29 0,34 0,4 0,28 0,33 0,38
U75 0,29 0,34 0,39 0,26 0,31 0,36 0,24 0,29 0,34 0,23 0,28 0,32 0,22 0,26 0,31
A80
U6,75 0,79 0,83 0,86 0,78 0,82 0,85 0,76 0,8 0,84 0,75 0,79 0,83 0,73 0,78 0,82
U12 0,75 0,79 0,83 0,72 0,77 0,81 0,7 0,75 0,79 0,69 0,74 0,78 0,68 0,73 0,77
U20 0,63 0,69 0,74 0,61 0,66 0,71 0,59 0,64 0,7 0,57 0,63 0,68 0,55 0,61 0,67
U30 0,53 0,59 0,64 0,51 0,57 0,62 0,49 0,55 0,6 0,47 0,53 0,58 0,45 0,51 0,57
U50 0,45 0,51 0,57 0,42 0,48 0,53 0,4 0,45 0,51 0,38 0,44 0,49 0,37 0,42 0,48
U80 0,3 0,35 0,41 0,28 0,33 0,38 0,27 0,31 0,37 0,25 0,3 0,35 0,24 0,28 0,33
29
Worm gear sets
Tolerance
Backlash tolerances for worm gears (valid for gears with a pressure angle of 15°)
ß0 corresponds to m of the worm
Pitch diameter Module Backlash tol. at pitch diameter [mm]
of the worm gear mn ß0 up to 24° ß0 over 24°
min. max. min. max.
over 12 up to 25 0,4 - 0,6 0,07 0,092 0,077 0,102
>0,6 - 1,3 0,075 0,099 0,083 0,109
>1,3 - 2,0 0,08 0,106 0,089 0,117
over 25 up to 50 0,4 - 0,6 0,075 0,099 0,083 0,108

>0,6 - 1,3 0,08 0,106 0,089 0,117
>1,3 - 2,0 0,086 0,114 0,095 0,125
>2,0 - 4,0 0,094 0,124 0,103 0,137
over 50 up to 100 0,4 - 0,6 0,08 0,106 0,089 0,117

>0,6 - 1,3 0,086 0,114 0,095 0,125
>1,3 - 2,0 0,094 0,124 0,103 0,137
>2,0 - 4,0 0,102 0,134 0,112 0,148
The backlash values are based on an ideal center distance. More backlash will appear if the
center distance is actually at the upper tolerance. 0.05mm above ideal center distance will
result in 0.027 mm more backlash.
Lubrication
Lubrication has an essential influence on efficiency, heat generation and life time. A good choice is a
synthetic oil on the basis of polyglykol and synthetic oil or grease on the basis of polyalphaolefin.
Moreover polyalphaolefin has a high compatibility to common sealing materials.
High viscosity synthetic oils (ISO VG 680 bzw. ISO VG 1000) are used preferably for worm gear sets.
In case of smaller center distances mineral or synthetic grease in consistency-class 0 up to 00 can be
used as well.
Comparison of the different basis oils

Characteristics Mineral oil Polyalphaolefin Polyglykol
synth. synth.
Viscosity at low temp. 4 3 3
Wear protection 4 2 1
Frictional behaviour 3 2 1
High temp. Oxidation stability 4 2 1
Water seperation ability 4 2 5
Air release ability 3 2 4
Rust protection 1 1 3
Mix with mineral oil - 1 5
Laquer compatibility 1 1 3
Seal compatibility 1 1 3
Low evaporation losses 4 1 3
1=excellent 2=very good 3=good 4=sufficient 5=bad

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1

Worm gear sets

Metric conversion table

Metric units Factor English units

Plastic worm gears

Mechanical characteristics: POM PA 66

Tensile strength Rm with 23°C: 70 N/mm2 50 N/mm2

Tensile strength Rm with 70°C: 48 N/mm2 35 N/mm2

Subject to technical changes

G-CuSn12 GZ-CuSn12 GC-CuSn12

G-CuSn12Ni GZ-CuSn12Ni GC-CuSn12Ni

G = dead mold casting

CuAl10Fe3 Mn2 DIN 17665 / 17672

CuAl10Fe3 Mn2 CuAl10Ni5F4

Factor n1 1 1,12 1,2 1,26 1,33 1,49 1,67

life time appr. 3000 h appr. 1500 h appr. 6000 h

factor Lh 1 1,4 0,71

Subject to technical changes

worm gear set A40 U35, lubrication with mineral oil,

Question: What's the expected maximum torque?

Output torque: =T2 (Mineral oil) x n1 (Factor) x Lh (Factor)

= 37,2 Nm x 1,26 x 1,4 T2 see table on page 14

Shocks none moderate heavy

No. of starts 10/h 60/h 360/h

duty cycle <40 % <70 % <100 %

2. Calculation example (with consideration of the operating conditions)

Subject to technical changes

Shocks or vibrations can neutralize self-locking.

Mounting of the worm gear

Move gear in Correct Move gear in

Subject to technical changes

with: => efficiency with driving worm gear

if is negative, self locking is likely.

Customer-Specific Worm Gear Sets

Crossed helical gears

Subject to technical changes

Subject to technical changes

Wormgear pressure angle 15°

i = gear ratio da1 = tip diameter (worm) MG = mineral grease

Catalog worm wormgear T2 [Nm]No.

** The hub diameter of the A17U50 worm is 9 mm.

All worms and worm gears stocked right hand only.

Subject to technical changes

i = gear ratio da1 = tip diameter (worm) MG = mineral grease

Catalog worm wormgear T2 [Nm]No.

All worms and worm gears stocked right hand only.

Subject to technical changes

i = gear ratio da1 = tip diameter (worm) MG = mineral grease

Catalog worm wormgear T2 [Nm]No.

All worms and worm gears stocked right hand only.

Subject to technical changes

i = gear ratio da1 = tip diameter (worm) MG = mineral grease

Catalog worm wormgear T2 [Nm]No.

Subject to technical changes

i = gear ratio da1 = tip diameter (worm) MG = mineral grease

Catalog worm wormgear T2 [Nm]No.

Subject to technical changes

Worm center distance

* Width tolerance of the keyway in the area of the teeth.

* Width tolerance of the keyway in the area of the teeth.