Why Not to Use Worm Gears
There is one especially glaring reason one would not choose a worm gear more than a typical gear: lubrication. The movement between your worm and the wheel gear faces is completely sliding. There is absolutely no rolling element of the tooth get in touch with or interaction. This makes them relatively difficult to lubricate.
The lubricants required are usually high viscosity (ISO 320 and greater) and thus are challenging to filter, and the lubricants required are usually specialized in what they perform, requiring something to be on-site particularly for that type of equipment.
Worm Gear Lubrication
The main problem with a worm gear is how it transfers power. It really is a boon and a curse at the same time. The spiral movement allows large sums of reduction in a comparatively little bit of space for what’s required if a typical helical gear were used.
This spiral motion also causes a remarkably problematic condition to be the primary mode of power transfer. This is often called sliding friction or sliding use.
With a typical gear set the energy is transferred at the peak load point on the tooth (referred to as the apex or pitchline), at least in a rolling wear condition. Sliding occurs on either part of the apex, however the velocity is relatively low.
With a worm gear, sliding motion may be the only transfer of power. As the worm slides over the tooth of the wheel, it gradually rubs off the lubricant film, until there is absolutely no lubricant film left, and for that reason, the worm rubs at the steel of the wheel in a boundary lubrication regime. When the worm surface leaves the wheel surface area, it picks up more lubricant, and starts the procedure over again on another revolution.
The rolling friction on an average gear tooth requires little in the form of lubricant film to fill in the spaces and separate the two components. Because sliding occurs on either aspect of the apparatus tooth apex, a slightly higher viscosity of lubricant than is usually strictly needed for rolling wear must overcome that load. The sliding takes place at a comparatively low velocity.
The worm on a worm set gear turns, even though turning, it crushes against the strain that is imposed on the wheel. The only method to avoid the worm from touching the wheel is to possess a film thickness huge enough never to have the whole tooth surface area wiped off before that area of the worm is out of the strain zone.
This scenario requires a special kind of lubricant. Not just will it should be a comparatively high viscosity lubricant (and the bigger the strain or temperature, the bigger the viscosity must be), it will need to have some way to greatly help conquer the sliding condition present.
Read The Right Way to Lubricate Worm Gears to learn more on this topic.
Custom Worm Gears
Worm Gears are right angle drives providing large quickness ratios on comparatively short center distances from 1/4” to 11”. When correctly mounted and lubricated they function as quietist and smoothest working type of gearing. Due to the high ratios feasible with worm gearing, optimum speed reduction could be accomplished in much 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 big degree on the helix position of the worm. Multiple thread worms and gears with higher helix position prove 25% to 50% more efficient than single thread worms. The mesh or engagement of worms with worm gears generates a sliding action leading to considerable friction and higher loss of efficiency beyond other types of gearing. The use of hardened and ground worm swith bronze worm gears boosts efficiency.
LUBRICATION can be an essential factor to improve efficiency in worm gearing. Worm equipment action generates considerable heat, decreasing efficiency. The quantity of power transmitted at a given temperature improves as the effectiveness of the gearing improves. Proper lubrication enhances effectiveness by reducing friction and high temperature.
RATIOS of worm equipment sets are dependant on dividing the amount of teeth in the gear by the amount of threads. Thus solitary threads yield higher ratios than multiple threads. All Ever-Power. worm gear pieces can be found with either left or right hand threads. Ever-Power. worm equipment sets are offered with Single, Double, Triple and Qua-druple Threads.
Basic safety PROVISION: Worm gearing should not be used because a locking mechanism to hold heavy weights where reversing actions could cause harm or injury. In applications where potential harm is nonexistent and self-locking is desired against backward rotation after that use of an individual thread worm with a minimal helix angle immediately locks the worm gear drive against backward rotation.
MATERIAL recommended for worms is hardened steel and bronze for worm gears. Nevertheless, depending on the application unhardened steel worms operate adequately and more economically with cast iron worm gears at 50% horsepower ratings. Furthermore to steel and hardenedsteel, worms can be found in stainless, aluminium, bronze and nylon; worm gears can be found in steel, hardened metal, stainless, light weight aluminum, nylon and non-metallic (phenolic).
Ever-Power also sells equipment tooth measuring products called Ever-Power! Gear Gages decrease mistakes, save money and time when identifying and buying gears. These pitch templates are available in nine sets to recognize all the standard pitch sizes: Diametral Pitch “DP”, Circular Pitch “CP”, External Involute Splines, Metric Module “MOD”, Stub Tooth, Great Pitches, Coarse Pitches and Uncommon Pitches. Make reference to the section on GEAR GAGES for catalog worm drive shaft figures when ordering.
Why Not to Use Worm Gears