Why Not to Use Worm Gears
There is one particularly glaring reason one would not choose a worm gear more than a standard gear: lubrication. The motion between your worm and the wheel equipment faces is completely sliding. There is no rolling component to the tooth get in touch with or conversation. This makes them fairly difficult to lubricate.
The lubricants required are usually very high viscosity (ISO 320 and better) and therefore are hard to filter, and the lubricants required are usually specialized in what they perform, requiring a product to be on-site particularly for that type of equipment.
Worm Gear Lubrication
The primary 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 reduction in a comparatively small amount of space for what’s required if a standard helical gear were used.
This spiral motion also causes a remarkably problematic condition to be the principal mode of power transfer. That is commonly known as sliding friction or sliding use.
With a worm drive shaft typical gear set the power is transferred at the peak load stage on the tooth (known as the apex or pitchline), at least in a rolling wear condition. Sliding happens on either aspect 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 slowly rubs off the lubricant film, until there is absolutely no lubricant film left, and as a result, the worm rubs at the steel of the wheel in a boundary lubrication regime. When the worm surface area leaves the wheel surface, it accumulates more lubricant, and begins the procedure over again on the next revolution.
The rolling friction on a typical gear tooth requires small in the way of lubricant film to complete the spaces and separate both components. Because sliding takes place on either part of the apparatus tooth apex, a somewhat higher viscosity of lubricant than is certainly strictly necessary for rolling wear must overcome that load. The sliding occurs at a relatively low velocity.
The worm on a worm set gear turns, even though turning, it crushes against the strain that’s imposed on the wheel. The only way to avoid the worm from touching the wheel is definitely to have a film thickness large enough never to have the whole tooth surface wiped off before that section of the worm is out of the strain zone.
This scenario takes a special sort of lubricant. Not just will it should be a relatively high viscosity lubricant (and the bigger the strain or temperature, the higher the viscosity should be), it will need to have some way to greatly help conquer the sliding condition present.
Read The Right Method to Lubricate Worm Gears to find out more on this topic.
Custom Worm Gears
Worm Gears are right angle drives providing huge speed ratios on comparatively short center distances from 1/4” to 11”. When correctly installed and lubricated they function as quietist and smoothest working type of gearing. Due to the high ratios feasible with worm gearing, maximum speed reduction could be accomplished in much less space than 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 level on the helix angle of the worm. Multiple thread worms and gears with higher helix position prove 25% to 50% more efficient than one thread worms. The mesh or engagement of worms with worm gears creates a sliding action leading to considerable friction and better lack of efficiency beyond other styles of gearing. The usage of hardened and ground worm swith bronze worm gears improves efficiency.
LUBRICATION is an essential factor to improve efficiency in worm gearing. Worm gear action generates considerable high temperature, decreasing efficiency. The quantity of power transmitted at a given temperature increases as the effectiveness of the gearing improves. Proper lubrication enhances effectiveness by reducing friction and heat.
RATIOS of worm gear sets are determined by dividing the number of teeth in the gear by the amount of threads. Thus solitary threads yield higher ratios than multiple threads. All Ever-Power. worm gear sets can be found with either still left or right hands threads. Ever-Power. worm gear sets can be found with Single, Dual, Triple and Qua-druple Threads.
Basic safety PROVISION: Worm gearing should not be used since a locking mechanism to carry large weights where reversing actions can cause harm or damage. In applications where potential harm is nonexistent and self-locking is desired against backward rotation then use of a single thread worm with a minimal helix angle automatically locks the worm gear drive against backward rotation.
Materials 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. Furthermore to metal and hardenedsteel, worms are available in stainless, aluminium, bronze and nylon; worm gears can be found in steel, hardened metal, stainless, aluminium, nylon and nonmetallic (phenolic).
Ever-Power also sells equipment tooth measuring gadgets called Ever-Power! Gear Gages reduce mistakes, save time and money when identifying and buying gears. These pitch templates can be found in nine sets to identify all the standard pitch sizes: Diametral Pitch “DP”, Circular Pitch “CP”, Exterior Involute Splines, Metric Module “MOD”, Stub Tooth, Fine Pitches, Coarse Pitches and Uncommon Pitches. Make reference to the section on Equipment GAGES for catalog quantities when ordering.
worm drive shaft
Why Not to Use Worm Gears