Why Not to Use Worm Gears
There is one especially glaring reason why one would not select a worm gear more than a typical gear: lubrication. The movement between your worm and the wheel equipment faces is completely sliding. There is 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 therefore are hard 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 primary 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 huge amounts of decrease in a comparatively small amount of space for what is 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 commonly known as sliding friction or sliding put on.
With an average 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 takes place on either side of the apex, however the velocity is fairly low.
With a worm gear, sliding motion is 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 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 area, it picks up 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 fill in the spaces and separate both components. Because sliding happens on either side of the apparatus tooth apex, a slightly higher viscosity of lubricant than is definitely strictly necessary for rolling wear is required to overcome that load. The sliding occurs at a comparatively low velocity.
The worm on a worm set gear turns, even though worm drive shaft turning, it crushes against the load that’s imposed on the wheel. The only method to prevent the worm from touching the wheel can be to possess a film thickness large enough never to have the entire tooth surface area wiped off before that portion of the worm is out of the strain zone.
This scenario requires a special kind of lubricant. Not only will it will have to be a comparatively high viscosity lubricant (and the higher the strain or temperature, the higher the viscosity must be), it will need to have some way to greatly help overcome 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 correct angle drives providing large quickness ratios on comparatively brief 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, maximum speed reduction can be accomplished in 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 large level on the helix angle of the worm. Multiple thread worms and gears with higher helix angle prove 25% to 50% more efficient 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 utilization of hardened and ground worm swith bronze worm gears raises efficiency.
LUBRICATION can be an essential factor to improve effectiveness in worm gearing. Worm equipment action generates considerable temperature, decreasing efficiency. The amount of power transmitted at a given temperature improves as the performance of the gearing raises. Proper lubrication enhances effectiveness by reducing friction and high temperature.
RATIOS of worm gear sets are dependant on dividing the number of teeth in the apparatus by the number of threads. Thus one threads yield higher ratios than multiple threads. All Ever-Power. worm gear sets are available with either remaining or right hands threads. Ever-Power. worm gear sets can be found with Single, Double, Triple and Qua-druple Threads.
Protection PROVISION: Worm gearing shouldn’t be used since a locking mechanism to carry heavy weights where reversing actions could cause harm or damage. In applications where potential damage is non-existent and self-locking is desired against backward rotation after that use of an individual thread worm with a minimal helix angle instantly locks the worm gear drive against backward rotation.
MATERIAL recommended for worms is certainly 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. In addition 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 non-metallic (phenolic).
Ever-Power also sells equipment tooth measuring products called Ever-Power! Gear Gages decrease mistakes, save time and money when identifying and buying gears. These pitch templates are available in nine sets to recognize all the regular pitch sizes: Diametral Pitch “DP”, Circular Pitch “CP”, Exterior Involute Splines, Metric Module “MOD”, Stub Tooth, Good Pitches, Coarse Pitches and Uncommon Pitches. Make reference to the section on GEAR GAGES for catalog amounts when ordering.
Why Not to Use Worm Gears