Worm Gears are right angle drives providing large speed ratios on
comparatively short center distances from 1/4” to 11”. When properly
mounted and lubricated they function as the quietest and smoothest
running type of gearing. Because of the high ratios possible with worm
gearing, maximum speed reduction can be accomplished in less space
than many other types of gearing. Worm and worm gears operate on
non-intersecting shafts at 90° angles.
EFFICIENCY of worm gear drives depends to a large extent on the helix
angle of the worm. Multiple thread worms and gears with higher helix
angle prove 25% to 50% more efficient than single thread worms. The
mesh or engagement of worms with worm gears produces a sliding
action causing considerable friction and greater loss of efficiency
beyond other types of gearing. The use of hardened and ground worm
swith bronze worm gears increases efficiency.
LUBRICATION is an essential factor to improve efficiency in worm
gearing. Worm gear action generates considerable heat, decreasing
efficiency. The amount of power transmitted at a given temperature
increases as the efficiency of the gearing increases. Proper lubrication
enhances efficiency by reducing friction and heat.
RATIOS of worm gear sets are determined by dividing the number of
teeth in the gear by the number of threads. Thus single threads yield
higher ratios than multiple threads. All RUSH GEARS inc.™ worm gear
sets are available with either left or right hand threads. RUSH GEARS
inc.™ worm gear sets are offered with Single, Double, Triple and
SAFETY PROVISION: Worm gearing should not be used as a locking
mechanism to hold heavy weights where reversing action can cause
harm or injury. In applications where potential harm is non-existent and
self-locking is desired against backward rotation then use of a single
thread worm with a low helix angle automatically locks the worm gear
drive against backward rotation.
MATERIAL recommended for worms is hardened steel and bronze for
worm gears. However, depending on the application unhardened steel
worms operate adequately and more economically with cast iron worm
gears at 50% horsepower ratings. In addition to steel and hardenedsteel,
worms are available in stainless, aluminum, bronze and nylon;
worm gears are available in steel, hardened steel, stainless, aluminum,
nylon and non-metallic (phenolic).
RUSH GEARS inc.™ also sells gear tooth measuring devices called GEAR
GAGES! Gear Gages reduce mistakes, save time and money when
identifying and ordering gears. These pitch templates are available in
nine sets to identify all the standard pitch sizes: Diametral Pitch “DP”,
Circular Pitch “CP”, External Involute Splines, Metric Module “MOD”,
Stub Tooth, Fine Pitches, Coarse Pitches and Unusual Pitches. Refer
to the section on GEAR GAGES for catalog numbers when ordering.