Worm Gears are right angle drives providing huge velocity ratios on comparatively short center distances from 1/4” to 11”. When properly mounted and lubricated they function as quietist and smoothest working type of gearing. Because of the high ratios possible with worm gearing, optimum speed reduction can be accomplished in much less space than many other types of gearing.
EFFICIENCY of worm equipment drives depends to a large extent on the helix angle of the worm. Multiple thread worms and gears with higher helix position prove 25% to 50% better than single thread worms. The mesh or engagement of worms with worm gears produces a sliding action leading to considerable friction and greater lack of efficiency beyond other styles of gearing. The utilization of hardened and surface worm swith bronze worm gears increases efficiency.
LUBRICATION is an essential factor to boost effectiveness in worm gearing. Worm equipment action generates considerable heat, decreasing efficiency. The quantity of power transmitted at a given temperature boosts as the efficiency of the gearing raises. Proper lubrication enhances performance by reducing friction and high temperature.
RATIOS of worm equipment sets are determined by dividing the number of teeth in the gear by the number of threads. Thus solitary threads yield higher ratios than multiple threads.
SAFETY PROVISION: Worm gearing shouldn’t be used as a locking mechanism to carry heavy weights where reversing actions can cause harm or injury. In Nylon Gear Rack applications where potential harm is non-existent and self-locking is preferred against backward rotation then use of an individual thread worm with a low helix angle instantly locks the worm gear drive against backward rotation.
Materials recommended for worms is usually hardened steel and bronze for worm gears. However, depending on the application unhardened metal 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, light weight aluminum, bronze and nylon; worm gears are available in steel, hardened metal, stainless, aluminum, nylon and non-metallic (phenolic).
Gear racks are used to convert rotating movement into linear motion. A gear rack has straight tooth cut into one surface of a square or round section of rod and operates with a pinion, which is definitely a small cylindrical gear meshing with the apparatus rack. Generally, gear rack and pinion are collectively known as “rack and pinion”. There are plenty of methods to use gears.
There are applications where the gear rack is stationary, as the pinion traverses and others where in fact the pinion rotates on a fixed axis while the gear rack moves. The previous is used widely in conveying systems as the latter can be used in extrusion systems and lifting/lowering applications.