Why Not to Use Worm Gears
There is one especially glaring reason why one would not select a worm gear more than a standard gear: lubrication. The movement between the worm and the wheel equipment faces is completely sliding. There is absolutely no rolling element of the tooth get in touch with or conversation. This makes them relatively difficult to lubricate.
The lubricants required are often very high viscosity (ISO 320 and higher) and thus are challenging to filter, and the lubricants required are usually specialized in what they perform, requiring something to be on-site specifically for that kind 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 simultaneously. The spiral movement allows huge amounts of decrease in a comparatively little bit of space for what’s required if a standard helical equipment were used.
This spiral motion also causes a remarkably problematic condition to be the principal mode of power transfer. This is often called sliding friction or sliding wear.
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 happens on either part of the apex, but the velocity is fairly 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 remaining, and for that reason, the worm rubs at the metal of the wheel in a boundary lubrication regime. When the worm surface leaves the wheel surface, it worm drive shaft accumulates more lubricant, and begins the procedure over again on the next revolution.
The rolling friction on a typical gear tooth requires little in the form of lubricant film to complete the spaces and separate the two components. Because sliding happens on either aspect of the gear tooth apex, a somewhat higher viscosity of lubricant than is definitely strictly needed for rolling wear must overcome that load. The sliding occurs at a relatively low velocity.
The worm on a worm set gear turns, and while turning, it crushes against the load that’s imposed on the wheel. The only method to avoid the worm from touching the wheel is definitely to possess a film thickness huge enough never to have the entire tooth surface wiped off before that portion of the worm is out of the strain zone.
This scenario takes a special kind of lubricant. Not just will it should be a relatively high viscosity lubricant (and the bigger the strain or temperature, the higher the viscosity must be), it will need to have some way to help get over the sliding condition present.
Read The Right Method to Lubricate Worm Gears to learn more on this topic.
Custom Worm Gears
Worm Gears are correct angle drives providing huge speed ratios on comparatively brief center distances from 1/4” to 11”. When properly installed and lubricated they function as quietist and smoothest operating type of gearing. Due to the high ratios possible with worm gearing, optimum speed reduction can be accomplished in less space than a great many other types of gearing. Worm and worm gears operate on nonintersecting 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 angle prove 25% to 50% better than solitary thread worms. The mesh or engagement of worms with worm gears generates a sliding action causing considerable friction and better loss of efficiency beyond other styles of gearing. The use of hardened and floor worm swith bronze worm gears boosts efficiency.
LUBRICATION can be an essential factor to boost efficiency in worm gearing. Worm gear action generates considerable warmth, decreasing efficiency. The amount of power transmitted at a given temperature improves as the efficiency of the gearing increases. 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 one threads yield higher ratios than multiple threads. All Ever-Power. worm gear sets can be found with either remaining or right hand threads. Ever-Power. worm gear sets can be found with Single, Double, Triple and Qua-druple Threads.
Security PROVISION: Worm gearing shouldn’t be used because a locking mechanism to hold weighty weights where reversing actions could cause harm or injury. In applications where potential damage is nonexistent and self-locking is desired against backward rotation after that use of a single thread worm with a minimal helix angle automatically locks the worm equipment drive against backward rotation.
MATERIAL recommended for worms is usually hardened steel and bronze for worm gears. However, depending on the application form 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, light weight aluminum, bronze and nylon; worm gears can be found in steel, hardened metal, stainless, aluminum, nylon and nonmetallic (phenolic).
Ever-Power also sells equipment tooth measuring gadgets called Ever-Power! Gear Gages decrease mistakes, save time and money when identifying and ordering gears. These pitch templates can be found in nine sets to recognize all the standard pitch sizes: Diametral Pitch “DP”, Circular Pitch “CP”, Exterior Involute Splines, Metric Module “MOD”, Stub Tooth, Great Pitches, Coarse Pitches and Unusual Pitches. Make reference to the section on Equipment GAGES for catalog figures when ordering.
Why Not to Use Worm Gears