Helical Gear Reducer

Worm gears are often used when large rate reductions are needed. The decrease ratio depends upon the number of starts of the worm and quantity of teeth on the worm gear. But worm gears have sliding contact which is peaceful but will produce heat and have relatively low transmission efficiency.
As for the materials for production, in general, worm is made from hard metal as the worm gear is made from relatively soft metallic such as aluminum bronze. This is because the number of teeth on the worm equipment is relatively high in comparison to worm using its number of begins being generally 1 to 4, by reducing the worm equipment hardness, the friction on the worm tooth is reduced. Another feature of worm manufacturing is the need of specialized machine for gear trimming and tooth grinding of worms. The worm equipment, however, may be made out of the hobbing machine utilized for spur gears. But because of the various tooth shape, it is not possible to cut several gears simultaneously by stacking the apparatus blanks as can be done with spur gears.
The applications for worm gears include equipment boxes, angling pole reels, guitar string tuning pegs, and where a delicate velocity adjustment by utilizing a huge speed reduction is necessary. When you can rotate the worm gear by worm, it is normally not possible to rotate worm by using the worm gear. That is called the personal locking feature. The self locking feature cannot continually be assured and another method is preferred for true positive reverse prevention.
Also there is duplex worm gear type. When working with these, you’ll be able to adjust backlash, as when the teeth put on necessitates backlash adjustment, without needing a modify in the center distance. There are not too many manufacturers who can generate this kind of worm.
The worm gear is more commonly called worm wheel in China.
A worm gear is a gear comprising a shaft with a spiral thread that engages with and drives a toothed wheel. Worm gears are a vintage style of gear, and a version of 1 of the six simple machines. Essentially, a worm equipment is usually a screw butted against what looks like a standard spur gear with slightly angled and curved teeth.
It adjustments the rotational motion by 90 degrees, and the plane of motion also changes because of the placement of the worm upon the worm wheel (or simply “the wheel”). They are typically comprised of a steel worm and a brass wheel.
Worm Gear
Figure 1. Worm gear. Most worms (however, not all) are at underneath.
How Worm Gears Work
An electric electric motor or engine applies rotational power via to the worm. The worm rotates against the wheel, and the screw face pushes on the teeth of the wheel. The wheel is pushed against the load.
Worm Gear Uses
There are a few reasons why one would choose a worm gear over a standard gear.
The first one may be the high reduction ratio. A worm gear can have an enormous reduction ratio with small effort – all one must do is definitely add circumference to the wheel. Therefore you can use it to either significantly increase torque or greatly reduce speed. It’ll typically consider multiple reductions of a conventional gearset to attain the same reduction level of a single worm gear – meaning users of worm gears have fewer shifting parts and fewer places for failure.
A second reason to use a worm gear may be the inability to reverse the direction of power. Due to the friction between the worm and the wheel, it is virtually not possible for a wheel with push used to it to start the worm moving.
On a standard gear, the input and output could be switched independently once enough force is applied. This necessitates adding a backstop to a standard gearbox, further raising the complication of the apparatus set.
YOU WILL WANT TO to Use Worm Gears
There is one particularly glaring reason why one would not choose a worm gear over a standard gear: lubrication. The movement between the worm and the wheel gear faces is completely sliding. There is no rolling component to the tooth contact or interaction. This makes them relatively difficult to lubricate.
The lubricants required are usually high viscosity (ISO 320 and greater) and therefore are challenging to filter, and the lubricants required are typically specialized in what they do, requiring something to be on-site specifically 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 motion allows huge amounts of reduction in a comparatively little bit of space for what’s required if a typical 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.
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With a typical gear set the power is transferred at the peak load point on the tooth (known as the apex or pitchline), at least in a rolling wear condition. Sliding happens on either aspect of the apex, however 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 no lubricant film remaining, and for that reason, the worm rubs at the steel of the wheel in a boundary lubrication regime. When the worm surface area leaves the wheel surface, it picks up more lubricant, and begins the process once more on another revolution.
The rolling friction on an average gear tooth requires little in the way of lubricant film to fill in the spaces and separate both components. Because sliding happens on either part of the apparatus tooth apex, a somewhat higher viscosity of lubricant than is usually strictly needed for rolling wear is required to overcome that load. The sliding takes place 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 prevent the worm from touching the wheel is certainly to possess a film thickness large enough never to have the whole tooth surface wiped off before that portion of the worm has gone out of the load zone.
This scenario takes a special sort of lubricant. Not just will it should be a relatively high viscosity lubricant (and the higher the strain or temperature, the higher the viscosity must be), it will need to have some way to help conquer the sliding condition present.
Read The Right Way to Lubricate Worm Gears to find out more on this topic.
Viscosity may be the major element in avoiding the worm from touching the wheel in a worm gear set. As the load and size of gearing determines the mandatory lubricant, an ISO 460 or ISO 680 is fairly common, and an ISO 1000 isn’t unheard of. If you’ve ever tried to filter this range of viscosity, you know it is problematic because it is most likely that none of the filters or pumps you have on-site will be the appropriate size or rating to function properly.
Therefore, you’ll likely need to get a particular pump and filter for this type of unit. A lubricant that viscous requires a sluggish operating pump to prevent the lubricant from activating the filter bypass. It will require a huge surface area filter to permit the lubricant to stream through.
Lubricant Types to consider
One lubricant type commonly used in mixture with worm gears is mineral-based, compounded equipment oils. There are no additives which can be put into a lubricant that can make it conquer sliding wear indefinitely, however the organic or synthetic fatty additive mixture in compounded equipment oils results in good lubricity, providing a supplementary measure of protection from metal-to-metal contact.
Another lubricant type commonly used in mixture with worm gears is mineral-based, commercial extreme pressure (EP) gear oils. There are several problems with this kind of lubricant if you are using a worm gear with a yellow metallic (brass) component. However, should you have fairly low operating temps or no yellow steel present on the gear tooth surfaces, this lubricant is effective.
Polyalphaolefin (PAO) equipment lubricants work very well in worm equipment applications because they naturally possess good lubricity properties. With a PAO equipment oil, it’s important to view the additive package, because these can have EP additives. A standard-duty antiwear (AW) fortified gear oil will typically end up being acceptable, but check that the properties are compatible with most metals.
The author recommends to closely watch the use metals in oil evaluation testing to make sure that the AW package isn’t so reactive as to trigger significant leaching from the brass. The result should be far less than what would be noticed with EP even in a worst-case scenario for AW reactivity, nonetheless it can show up in metals examining. If you need a lubricant that can handle higher- or lower-than-typical temperatures, the right PAO-based product is probable available.
Polyalkylene glycols (PAG), a fourth kind of lubricant, are getting more prevalent. These lubricants have exceptional lubricity properties, and do not contain the waxes that cause low-temperature problems with many mineral lubricants, producing them a great low-temperature choice. Caution should be taken when using PAG oils because they are not compatible with mineral oils, and some seals and paints.
Metallurgy of Worm Gears
The most common worm gears are made with a brass wheel and a steel worm. This is because the brass wheel is normally easier to replace than the worm itself. The wheel is manufactured out of brass since it is designed to be sacrificial.
In the event that the two surfaces enter into contact, the worm is marginally safe from wear since the wheel is softer, and therefore, the majority of the wear occurs on the wheel. Oil evaluation reports on this type of unit more often than not show some level of copper and low levels of iron – consequently of the sacrificial wheel.
This brass wheel throws another problem into the lubrication equation for worm gears. If a sulfur-phosphorous EP gear essential oil is put into the sump of a worm gear with a brass wheel, and the temperature is definitely high enough, the EP additive will activate. In normal metal gears, this activation produces a thin layer of oxidation on the surface that helps to protect the apparatus tooth from shock loads and other extreme mechanical conditions.
On the brass surface however, the activation of the EP additive outcomes in significant corrosion from the sulfur. In a brief amount of time, you can shed a substantial portion of the strain surface area of the wheel and cause major damage.
Other Materials
Some of the less common materials found in worm gear sets include:
Steel worm and steel worm wheel – This application does not have the EP complications of brass gearing, but there is absolutely no room for error built into a gearbox like this. Repairs on worm gear sets with this combination of metal are typically more costly and additional time consuming than with a brass/steel worm equipment set. This is since the material transfer associated with failure makes both the worm and the wheel unusable in the rebuild.
Brass worm and brass worm wheel – This program is most likely found in moderate to light load situations because the brass can only keep up to a lower amount of load. Lubricant selection on this metal combination is flexible due to the lighter load, but one must still consider the additive limitations regarding EP due to the yellow metal.
Plastic on metal, upon plastic, and other comparable combinations – This is typically within relatively light load applications, such as robotics and auto components. The lubricant selection depends on the plastic in use, because many plastic varieties react to the hydrocarbons in regular lubricant, and thus will demand silicon-based or other non-reactive lubricants.
Although a worm gear will will have a couple of complications compared to a typical gear set, it can easily be an effective and reliable piece of equipment. With a little focus on set up and lubricant selection, worm gears can offer reliable service and also any other type of gear set.
A worm drive is one particular worm gear set system when a worm meshes with a worm equipment. Even it is simple, there are two important elements: worm and worm equipment. (Also, they are known as the worm and worm wheel) The worm and worm wheel is essential motion control element providing large velocity reductions. It can reduce the rotational velocity or raise the torque output. The worm drive motion advantage is that they can transfer movement in right angle. In addition, it has an interesting real estate: the worm or worm shaft can simply turn the gear, but the gear can not really switch the worm. This worm drive self-locking feature let the worm gear includes a brake function in conveyor systems or lifting systems.
An Intro to Worm Gearbox
The most important applications of worm gears can be used in worm gear box. A worm gearbox is named a worm decrease gearbox, worm equipment reducer or a worm drive gearbox. It includes worm gears, shafts, bearings, and box frames.
The worm gear, shafts, bearings load are supported by the package shell. So, the gearbox housing must have sufficient hardness. Or else, it will result in lower tranny quality. As the worm gearbox comes with a durable, tranny ratio, little size, self-locking ability, and simple framework, it is often used across an array of industries: Rotary desk or turntable, material dosing systems, car feed machinery, stacking machine, belt conveyors, farm picking lorries and more automation industry.
How exactly to Select High Efficient Worm Gearbox?
The worm gear manufacturing process is also relatively simple. However, there exists a low transmission efficiency problem if you don’t know the how to select the worm gearbox. 3 basic point to choose high worm equipment efficiency that you should know:
1) Helix position. The worm gear drive efficiency mostly depend on the helix angle of the worm. Usually, multiple thread worms and gears can be more efficient than one thread worms. Proper thread worms can increase performance.
2) Lubrication. To select a brand lubricating essential oil can be an essential factor to boost worm gearbox effectiveness. As the proper lubrication can reduce worm gear action friction and high temperature.
3) Materials selection and Gear Production Technology. For worm shaft, the material ought to be hardened steel. The worm gear materials should be aluminium bronze. By reducing the worm gear hardness, the friction on the worm the teeth is decreased. In worm manufacturing, to use the specific machine for gear reducing and tooth grinding of worms also can increase worm gearbox efficiency.
From a huge transmission gearbox capacity to a straight small worm gearbox load, you can choose one from an array of worm reducer that precisely matches your application requirements.
Worm Gear Package Assembly：
1) You can complete the set up in six various ways.
2) The installation should be solid and reliable.
3) Be sure to examine the connection between the engine and the worm equipment reducer.
4) You must make use of flexible cables and wiring for a manual installation.
With the help of the most advanced science and drive technology, we’ve developed several unique “square package” designed from high-quality aluminium die casting with a beautiful appearance. The modular worm gearbox design series: worm drive gearbox, parallel shaft gearbox, bevel helical gearbox, spiral bevel gearbox, coaxial gearbox, right angle gearbox. An NMRV series gearbox can be a typical worm gearbox with a bronze worm gear and a worm. Our Helical gearbox product line comprises of four universal series (R/S/K/F) and a step-less swiftness variation UDL series. Their framework and function are similar to an NMRV worm gearbox.
Worm gears are constructed of a worm and a equipment (sometimes referred to as a worm wheel), with non-parallel, nonintersecting shafts oriented 90 degrees to each other. The worm is certainly analogous to a screw with a V-type thread, and the gear is analogous to a spur gear. The worm is typically the generating component, with the worm’s thread advancing one’s teeth of the gear.
Such as a ball screw, the worm in a worm gear might have an individual start or multiple starts – and therefore there are multiple threads, or helicies, on the worm. For a single-start worm, each full turn (360 degrees) of the worm advances the gear by one tooth. Therefore a gear with 24 teeth provides a gear reduced amount of 24:1. For a multi-start worm, the gear reduction equals the number of teeth on the gear, divided by the number of starts on the worm. (This is different from almost every other types of gears, where the gear reduction can be a function of the diameters of both components.)
The worm in a worm gear assembly can have one start (thread) or multiple starts.
Image credit: Kohara Gear Market Company, Ltd.
The meshing of the worm and the apparatus is a mixture of sliding and rolling actions, but sliding contact dominates at high reduction ratios. This sliding actions causes friction and heat, which limits the effectiveness of worm gears to 30 to 50 percent. To be able to minimize friction (and therefore, high temperature), the worm and gear are made of dissimilar metals – for example, the worm may be produced of hardened steel and the gear manufactured from bronze or aluminum.
Although the sliding contact reduces efficiency, it provides extremely quiet operation. (The use of dissimilar metals for the worm and gear also contributes to quiet operation.) This makes worm gears ideal for use where noise should be minimized, such as in elevators. Furthermore, the use of a softer material for the gear means that it could absorb shock loads, like those skilled in large equipment or crushing machines.
The primary benefit of worm gears is their ability to provide high reduction ratios and correspondingly high torque multiplication. They can also be used as speed reducers in low- to medium-velocity applications. And, because their decrease ratio is based on the number of gear teeth only, they are more compact than other types of gears. Like fine-pitch lead screws, worm gears are usually self-locking, which makes them well suited for hoisting and lifting applications.
A worm equipment reducer is one type of reduction gear box which includes a worm pinion input, an output worm gear, and features a right angle result orientation. This type of reduction gear box is generally used to take a rated motor acceleration and create a low speed result with higher torque worth based on the decrease ratio. They often can resolve space-saving problems because the worm equipment reducer is one of the sleekest reduction gearboxes available due to the small diameter of its output gear.
worm gear reducerWorm equipment reducers are also a favorite type of swiftness reducer because they provide the greatest speed decrease in the smallest package. With a high ratio of speed reduction and high torque result multiplier, it’s unsurprising that lots of power transmission systems utilize a worm gear reducer. Some of the most common applications for worm gears are available in tuning instruments, medical examining equipment, elevators, protection gates, and conveyor belts.
Torque Transmission provides two sizes of worm gear reducer, the SW-1 and the SW-5 and both are available in a range of ratios. The SW-1 ratios include 3.5:1 to 60:1 and the SW-5 ratios include 5:1 to 100:1. Both these options are produced with durable compression-molded glass-fill up up polyester housings for a long lasting, long lasting, light weight speed reducer that is also compact, non-corrosive, and nonmetallic.
Features
Our worm equipment reducers offer an option of a solid or hollow output shaft and show an adjustable mounting placement. Both the SW-1 and the SW-5, nevertheless, can withstand shock loading better than other decrease gearbox styles, making them perfect for demanding applications.
Rugged compression-molded glass-fill up polyester housing
Light-weight and compact
Non corrosive
Non metallic
Range of ratios
SW-1, 3.5:1 to 60:1
SW-5, 5:1 to 100:1
Grease Lubrication
Solid or Hollow output shaft
Adjustable mounting position
Overview
Technical Info
Low friction coefficient on the gearing for high efficiency.
Powered by long-long lasting worm gears.
Minimal speed fluctuation with low noise and low vibration.
Lightweight and compact in accordance with its high load capacity.
Compact design
Compact design is among the key terms of the standard gearboxes of the BJ-Series. Further optimisation may be accomplished by using adapted gearboxes or special gearboxes.
Low noise
Our worm gearboxes and actuators are really quiet. This is due to the very smooth operating of the worm gear combined with the utilization of cast iron and high precision on element manufacturing and assembly. Regarding the our precision gearboxes, we consider extra care of any sound which can be interpreted as a murmur from the apparatus. So the general noise degree of our gearbox is reduced to an absolute minimum.
Angle gearboxes
On the worm gearbox the input shaft and output shaft are perpendicular to each other. This often proves to be a decisive advantage producing the incorporation of the gearbox considerably simpler and more compact.The worm gearbox is an angle gear. This is often an advantage for incorporation into constructions.
Solid bearings in solid housing
The output shaft of the BJ worm gearbox is very firmly embedded in the apparatus house and is ideal for direct suspension for wheels, movable arms and other parts rather than having to create a separate suspension.
Self locking
For larger equipment ratios, BJ-Gear’s worm gearboxes provides a self-locking impact, which in many circumstances can be utilized as brake or as extra protection. Also spindle gearboxes with a trapezoidal spindle are self-locking, making them perfect for an array of solutions.