Why Not to Use Worm Gears
There is one particularly glaring reason why one would not select a worm gear over a typical gear: lubrication. The motion between the worm and the wheel equipment faces is entirely sliding. There is no rolling component to 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 higher) and therefore are hard 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 simultaneously. The spiral movement allows huge amounts of reduction 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 primary mode of power transfer. That is commonly known as sliding friction or sliding put on.
With an average gear set the energy is transferred at the peak load stage on the tooth (known 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 is 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 area, it picks up more lubricant, and starts the procedure over again on the next revolution.
The rolling friction on an average gear tooth requires small in the form of lubricant film to fill in the spaces and separate both components. Because sliding occurs on either side of the apparatus tooth apex, a somewhat higher viscosity of lubricant than is strictly necessary for rolling wear must overcome that load. The sliding happens at a relatively low velocity.
The worm on a worm set gear turns, and while turning, it crushes against the strain that is imposed on the wheel. The only method to avoid the worm from touching the wheel is certainly to possess a film thickness huge enough never to have the whole tooth surface area wiped off before that portion of the worm is out of the load zone.
This scenario takes a special sort of lubricant. Not just will it will have to be a comparatively high viscosity lubricant (and the higher the load or temperature, the higher the viscosity should be), it will need to have some way to help overcome the sliding condition present.
Read The Right Way to Lubricate Worm Gears for more information on this topic.
Custom Worm Gears
Worm Gears are correct angle drives providing huge acceleration ratios on comparatively brief center distances from 1/4” to 11”. When properly installed and lubricated they function as quietist and smoothest running type of gearing. Due to the high ratios feasible with worm gearing, optimum speed reduction could be accomplished in much 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 large level on the helix position of the worm. Multiple thread worms and gears with higher helix position prove 25% to 50% better than solitary thread worms. The mesh or engagement of worms with worm gears creates a sliding action causing considerable friction and better lack of efficiency beyond other types of gearing. The utilization of hardened and surface worm swith bronze worm gears increases efficiency.
LUBRICATION is an essential factor to boost efficiency in worm gearing. Worm equipment action generates considerable warmth, decreasing efficiency. The quantity of power transmitted at confirmed temperature boosts as the performance of the gearing boosts. Proper lubrication enhances performance by reducing friction and high temperature.
RATIOS of worm gear sets are dependant on dividing the number of teeth in the gear by the number 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 gear sets can be found with Single, Dual, Triple and Qua-druple Threads.
SAFETY PROVISION: Worm gearing should not be used since a locking mechanism to hold weighty weights where reversing actions can cause harm or injury. In applications where potential damage is nonexistent and self-locking is preferred against backward rotation then use of an individual thread worm with a minimal helix angle immediately locks the worm gear drive against backward rotation.
Materials recommended for worms is definitely hardened steel and bronze for worm gears. Nevertheless, 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, aluminium, bronze and nylon; worm gears are available in steel, hardened steel, stainless, light weight aluminum, nylon and non-metallic (phenolic).
Ever-Power also sells gear tooth measuring gadgets called Ever-Power! Gear Gages reduce mistakes, save time and money when identifying and ordering gears. These pitch templates are available in nine sets to recognize all the regular pitch sizes: Diametral Pitch “DP”, Circular Pitch “CP”, External Involute Splines, Metric Module “MOD”, Stub Tooth, Good Pitches, Coarse Pitches and Uncommon Pitches. Make reference to the worm drive shaft section on Equipment GAGES for catalog quantities when ordering.
worm drive shaft
Why Not to Use Worm Gears