Worm gear sets0 pages

Framo - Worm gear sets

1

(Framo-Norm)

Framo® - Worm gear sets
Progressive manufacturing methods and long-standing experience in manufacturing and consulting made
Framo worm gear sets become a synonyme for quality. Since the 1950's Framo has sold more than 20 million
worm gear sets worldwide and became one of the world's biggest manufacturer of industrial high quality worm
gears.
More than 50 years of manufacturing and engineering experience in the field of worm gearing lead to the
industry's widest range of worm gear sets. Catalog worm gear sets in center distances between 17mm and
80mm can be ordered from stock. Custom worm gear sets are available on request.
Quality has always been an important sales criteria for our customers. Framo's quality management system
and measuring procedures is ISO 9001 : 2000 certified.
Metric conversion table
MORAT standard catalog worm gears are metric worm gears. The catalog data can be converted into 'English
measures' by using the following conversion table:
Metric units
Torque (Nm)
Distance (mm)

Factor
x 8.85
x 0.03937

English units
in.lb.
in.

ISO-tolerances
The worm gear drawings show ISO-tolerances like Ø32H7. If you are not familiar with ISO-tolerances please call
MORAT or the local distributor to get the precise dimensions.
Materials
The worms are made of case hardened steel. The bore and the worm profile are ground. 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) 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:
Strain limit RP0,2:
Strain at failure A5:
Hardness HB2,5/62,5:
Shearing strength:
Alternating stress:
• Good gliding characteristics
• High wear resistance

560 N/mm2
290 N/mm2
15%
140-170
470 N/mm2
170 N/mm2 (20x106 cycles)

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:
Tensile strength Rm with 70°C:
Temperature range:

70 N/mm2
48 N/mm2
-50 .... +100°C

50 N/mm2
35 N/mm2
-40 .... +100°C

DS-101e1/07.05

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.

Framo Morat GmbH & Co. KG

Po-box 10 • D-79869 Eisenbach / Hochschwarzwald
Höchst 7 • D-79871 Eisenbach / Hochschwarzwald
Homepage: http://www. framo-morat.com

Phone +49(0)7657 / 88-0 • Fax +49(0)7657 / 88-444
E-Mail: info@framo-morat.com