Helical Gear Reducer

Worm gears are often used when large acceleration reductions are needed. The decrease ratio is determined by the number of starts of the worm and quantity of the teeth on the worm gear. But worm gears have sliding get in touch with which is calm but will produce heat and have relatively low transmitting efficiency.
For the materials for production, in general, worm is constructed of hard metal as the worm gear is produced out of relatively soft steel such as for example aluminum bronze. That is since the number of teeth on the worm equipment is relatively high in comparison to worm with its number of starts being generally 1 to 4, by reducing the worm gear hardness, the friction on the worm tooth is reduced. Another feature of worm manufacturing is the need of specific machine for gear trimming and tooth grinding of worms. The worm gear, however, may be made out of the hobbing machine utilized for spur gears. But due to the various tooth shape, it isn’t possible to cut several gears simultaneously by stacking the gear blanks as can be done with spur gears.
The applications for worm gears include gear boxes, fishing pole reels, guitar string tuning pegs, and where a delicate swiftness adjustment by utilizing a large speed reduction is needed. While you can rotate the worm equipment by worm, it is generally not possible to rotate worm by using the worm gear. That is called the self locking feature. The self locking feature cannot always be assured and a separate method is recommended for accurate positive reverse prevention.
Also there is duplex worm gear type. When working with these, you’ll be able to adapt backlash, as when one’s teeth put on necessitates backlash adjustment, without needing a change in the guts distance. There aren’t too many producers who can generate this kind of worm.
The worm equipment is more commonly called worm wheel in China.
A worm equipment is a gear consisting of a shaft with a spiral thread that engages with and drives a toothed wheel. Worm gears are an old style of equipment, and a edition of one of the six basic machines. Fundamentally, a worm gear is usually a screw butted against what appears like a typical spur gear with slightly angled and curved teeth.
It changes the rotational movement by 90 degrees, and the plane of motion also changes because of the placement of the worm upon the worm wheel (or just “the wheel”). They are typically comprised of a metal worm and a brass wheel.
Worm Gear
Figure 1. Worm equipment. Most worms (however, not all) are at the bottom.
How Worm Gears Work
An electric motor or engine applies rotational power via to the worm. The worm rotates against the wheel, and the screw encounter pushes on one’s teeth of the wheel. The wheel is definitely pushed against the load.
Worm Gear Uses
There are a few reasons why one would select a worm gear over a standard gear.
The first one is the high reduction ratio. A worm gear can have a massive reduction ratio with small effort – all one should do is usually add circumference to the wheel. Therefore you can use it to either greatly increase torque or help reduce speed. It’ll typically take multiple reductions of a conventional gearset to achieve the same reduction level of a single worm gear – meaning users of worm gears have got fewer shifting parts and fewer places for failure.
A second reason to employ a worm gear may be the inability to reverse the path of power. Because of the friction between the worm and the wheel, it is virtually impossible for a wheel with power used to it to begin the worm moving.
On a standard gear, the input and output can be turned independently once enough force is used. This necessitates adding a backstop to a standard gearbox, further increasing the complication of the gear set.
Why Not to Use Worm Gears
There is one particularly glaring reason why one would not select a worm gear more than a standard gear: lubrication. The movement between your worm and the wheel gear faces is completely sliding. There is no rolling element of the tooth contact or conversation. This makes them relatively difficult to lubricate.
The lubricants required are usually very high viscosity (ISO 320 and higher) and thus are challenging to filter, and the lubricants required are typically specialized in what they perform, requiring something to be on-site particularly for that kind of equipment.
Worm Gear Lubrication
The main problem with a worm gear is how it transfers power. It is a boon and a curse simultaneously. The spiral movement allows large sums of reduction in a comparatively small amount of space for what’s required if a typical helical gear were used.
This spiral motion also causes an incredibly problematic condition to be the principal mode of power transfer. That is often called 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 occurs on either side of the apex, but the velocity is fairly low.
With a worm gear, sliding motion is the only transfer of power. As the worm slides across 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 metallic of the wheel in a boundary lubrication regime. When the worm surface leaves the wheel surface area, it accumulates more lubricant, and starts the process over again on another revolution.
The rolling friction on a typical gear tooth requires little in the way of lubricant film to complete the spaces and separate the two components. Because sliding happens on either side of the gear tooth apex, a somewhat higher viscosity of lubricant than can be strictly needed for rolling wear must overcome that load. The sliding takes place at a comparatively 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 way to prevent the worm from touching the wheel is usually to have a film thickness large enough never to have the whole tooth surface area wiped off before that portion of the worm has gone out of the load zone.
This scenario requires a special kind of lubricant. Not just will it should be a relatively high viscosity lubricant (and the bigger the load or temperature, the bigger the viscosity must be), it will need to have some way to greatly help overcome the sliding condition present.
Read The Right Way to Lubricate Worm Gears to learn more on this topic.
Viscosity may be the major element in avoiding the worm from touching the wheel in a worm equipment set. As the load and size of gearing determines the required lubricant, an ISO 460 or ISO 680 is fairly common, and an ISO 1000 is not unheard of. If you have ever tried to filter this range of viscosity, you understand it is problematic since it is probably that none of the filters or pumps you have got on-site would be the proper size or ranking to function properly.
Therefore, you’ll likely have to get a particular pump and filter for this kind of unit. A lubricant that viscous takes a gradual operating pump to prevent the lubricant from activating the filter bypass. It will require a huge surface area filter to allow the lubricant to flow through.
Lubricant Types to consider
One lubricant type commonly used with worm gears is mineral-based, compounded gear oils. There are no additives which can be put into a lubricant that may make it conquer sliding wear indefinitely, but the organic or synthetic fatty additive mixture in compounded equipment oils results in great lubricity, providing a supplementary way of measuring protection from metal-to-metal contact.
Another lubricant type commonly used in mixture with worm gears is mineral-based, industrial extreme pressure (EP) gear oils. There are some problems with this type of lubricant if you are using a worm equipment with a yellow metal (brass) component. However, if you have relatively low operating temps or no yellow metallic present on the gear tooth surfaces, this lubricant is effective.
Polyalphaolefin (PAO) gear lubricants work well in worm gear applications because they naturally have great lubricity properties. With a PAO equipment oil, it’s important to view the additive bundle, because these can possess EP additives. A standard-duty antiwear (AW) fortified gear essential oil will typically end up being acceptable, but check that the properties are appropriate for most metals.
The writer recommends to closely view the use metals in oil evaluation testing to ensure that the AW package isn’t so reactive concerning cause significant leaching from the brass. The effect should be much less than what will be seen with EP also in a worst-case situation for AW reactivity, but it can show up in metals assessment. If you want a lubricant that may manage higher- or lower-than-typical temperatures, a suitable PAO-based product is likely available.
Polyalkylene glycols (PAG), a fourth kind of lubricant, are getting more prevalent. These lubricants have superb lubricity properties, , nor contain the waxes that trigger low-temperature issues with many mineral lubricants, producing them an excellent low-temperature choice. Caution must be taken when working with PAG oils because they’re 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. That is because the brass wheel is typically easier to replace than the worm itself. The wheel is made out of brass since it was created to be sacrificial.
In the event that the two surfaces come into contact, the worm is marginally safe from wear because the wheel is softer, and for that reason, the majority of the wear occurs on the wheel. Oil analysis reports on this type of unit almost always show some level of copper and low levels of iron – as a result of the sacrificial wheel.
This brass wheel throws another problem in to the lubrication equation for worm gears. If a sulfur-phosphorous EP gear essential oil is put into the sump of a worm equipment with a brass wheel, and the temperature is certainly high enough, the EP additive will activate. In regular steel gears, this activation produces a thin layer of oxidation on the surface that really helps to protect the apparatus tooth from shock loads and various other extreme mechanical conditions.
On the brass surface however, the activation of the EP additive results in significant corrosion from the sulfur. In a short timeframe, you can lose a significant portion of the load surface of the wheel and cause major damage.
Other Materials
Some of the less common materials within worm gear pieces include:
Steel worm and steel worm wheel – This software doesn’t have the EP complications of brass gearing, but there is absolutely no room for error included in a gearbox like this. Repairs on worm equipment sets with this combination of metal are typically more costly and more time eating than with a brass/steel worm gear set. This is since the material transfer associated with failure makes both worm and the wheel unusable in the rebuild.
Brass worm and brass worm wheel – This program is most likely within moderate to light load circumstances because the brass can only hold up to a lesser quantity of load. Lubricant selection upon this metal combination is flexible because of the lighter load, but one must still consider the additive limitations regarding EP due to the yellow metal.
Plastic on metal, on plastic, and other similar combinations – That is typically within relatively light load applications, such as for example robotics and automotive components. The lubricant selection depends on the plastic in use, because many plastic varieties react to the hydrocarbons in regular lubricant, and thus will require silicon-based or other nonreactive lubricants.
Although a worm gear will will have a few complications compared to a standard gear set, it can simply be an effective and reliable piece of equipment. With a little attention to set up and lubricant selection, worm gears can provide reliable service in addition to any other kind of gear set.
A worm drive is one simple worm gear set mechanism when a worm meshes with a worm gear. Even it is simple, there are two important components: worm and worm gear. (They are also called the worm and worm wheel) The worm and worm wheel is important motion control element providing large swiftness reductions. It can reduce the rotational acceleration or raise the torque result. The worm drive motion advantage is that they can transfer movement in right angle. It also has an interesting property: 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 allow worm gear includes a brake function in conveyor systems or lifting systems.
An Launch to Worm Gearbox
The most important applications of worm gears is utilized in worm gear box. A worm gearbox is called a worm decrease gearbox, worm equipment reducer or a worm drive gearbox. It consists of worm gears, shafts, bearings, and box frames.
The worm equipment, shafts, bearings load are supported by the box shell. Therefore, the gearbox housing must have sufficient hardness. Or else, it’ll result in lower transmission quality. As the worm gearbox comes with a durable, transmission ratio, little size, self-locking ability, and simple framework, it is used across an array of industries: Rotary table or turntable, material dosing systems, auto feed machinery, stacking machine, belt conveyors, farm choosing lorries and more automation market.
How exactly to Select High Efficient Worm Gearbox?
The worm gear production process is also not at all hard. However, there exists a low transmission effectiveness problem if you don’t understand the how to select the worm gearbox. 3 basic indicate choose high worm equipment efficiency that you need to know:
1) Helix position. The worm equipment drive efficiency mostly rely on the helix position of the worm. Usually, multiple thread worms and gears can be more efficient than one thread worms. Proper thread worms can increase effectiveness.
2) Lubrication. To choose a brand lubricating essential oil is an essential factor to improve worm gearbox effectiveness. As the proper lubrication can decrease worm gear action friction and warmth.
3) Materials selection and Gear Production Technology. For worm shaft, the material ought to be hardened metal. The worm gear materials ought to be aluminium bronze. By reducing the worm gear hardness, the friction on the worm the teeth is reduced. In worm manufacturing, to use the specialized machine for gear trimming and tooth grinding of worms also can increase worm gearbox performance.
From a large transmission gearbox power to an even small worm gearbox load, you can choose one from an array of worm reducer that precisely suits your application requirements.
Worm Gear Box Assembly：
1) You can complete the set up in six different ways.
2) The installation must be solid and reliable.
3) Be sure to check the connection between your electric motor and the worm equipment reducer.
4) You must make use of flexible cables and wiring for a manual set up.
By using the innovative science and drive technology, we’ve developed several unique “square box” designed from high-quality aluminium die casting with a lovely appearance. The modular worm gearbox style series: worm drive gearbox, parallel shaft gearbox, bevel helical gearbox, spiral bevel gearbox, coaxial gearbox, correct angle gearbox. An NMRV series gearbox is certainly a typical worm gearbox with a bronze worm equipment and a worm. Our Helical gearbox product line consists of four universal series (R/S/K/F) and a step-less rate variation UDL series. Their structure and function act like an NMRV worm gearbox.
Worm gears are made of a worm and a gear (sometimes known as a worm wheel), with nonparallel, non-intersecting shafts oriented 90 degrees to each other. The worm can be analogous to a screw with a V-type thread, and the apparatus can be analogous to a spur gear. The worm is typically the traveling component, with the worm’s thread advancing the 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 complete turn (360 degrees) of the worm increases the equipment by one tooth. Therefore a gear with 24 teeth will provide a gear reduction of 24:1. For a multi-begin worm, the apparatus reduction equals the number of teeth on the gear, divided by the number of starts on the worm. (That is different from most other types of gears, where the gear reduction is definitely a function of the diameters of both components.)
The worm in a worm gear assembly can have one start (thread) or multiple starts.
Picture credit: Kohara Gear Market Company, Ltd.
The meshing of the worm and the gear is a mixture of sliding and rolling actions, but sliding contact dominates at high reduction ratios. This sliding action causes friction and temperature, which limits the effectiveness of worm gears to 30 to 50 percent. In order to minimize friction (and therefore, heat), the worm and gear are made of dissimilar metals – for example, the worm could be produced of hardened steel and the apparatus manufactured from bronze or aluminum.
Although the sliding contact decreases efficiency, it provides very quiet operation. (The use of dissimilar metals for the worm and gear also contributes to quiet procedure.) This makes worm gears ideal for use where sound should be minimized, such as in elevators. In addition, the use of a softer materials for the gear means that it can absorb shock loads, like those experienced in weighty equipment or crushing machines.
The primary benefit of worm gears is their capability to provide high reduction ratios and correspondingly high torque multiplication. They may also be used as rate reducers in low- to moderate-velocity applications. And, because their decrease ratio is based on the amount of gear teeth alone, they are smaller sized than other types of gears. Like fine-pitch lead screws, worm gears are typically self-locking, making them ideal for hoisting and lifting applications.
A worm equipment reducer is one type of reduction gear package which includes a worm pinion insight, an output worm equipment, and features a right angle output orientation. This kind of reduction gear package is normally used to take a rated motor speed and create a low speed result with higher torque value based on the reduction ratio. They often times can resolve space-saving problems since the worm gear reducer is one of the sleekest reduction gearboxes available due to the small diameter of its output gear.
worm gear reducerWorm gear reducers are also a popular type of acceleration reducer because they offer the greatest speed reduction in the smallest package. With a high ratio of speed reduction and high torque output multiplier, it’s unsurprising that lots of power transmission systems make use of a worm equipment reducer. Some of the most typical applications for worm gears can be found in tuning instruments, medical testing equipment, elevators, protection gates, and conveyor belts.
Torque Transmission offers two sizes of worm gear reducer, the SW-1 and the SW-5 and both are available in a variety 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 of these options are manufactured with rugged compression-molded glass-fill up polyester housings for a long lasting, long lasting, light-weight speed reducer that is also compact, noncorrosive, and nonmetallic.
Features
Our worm equipment reducers offer a choice of a solid or hollow output shaft and show an adjustable mounting position. Both the SW-1 and the SW-5, however, can endure shock loading better than other decrease gearbox styles, making them well suited 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-enduring worm gears.
Minimum 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 words of the typical gearboxes of the BJ-Series. Further optimisation can be achieved through the use of adapted gearboxes or special gearboxes.
Low noise
Our worm gearboxes and actuators are really quiet. This is because of the very smooth running of the worm gear combined with the use of cast iron and high precision on element manufacturing and assembly. Regarding the our precision gearboxes, we consider extra treatment of any sound which can be interpreted as a murmur from the gear. So the general noise level of our gearbox is certainly reduced to an absolute minimum.
Angle gearboxes
On the worm gearbox the input shaft and output shaft are perpendicular to each other. This frequently proves to become a decisive advantage producing the incorporation of the gearbox substantially simpler and smaller sized.The worm gearbox can be an angle gear. This is often an edge for incorporation into constructions.
Solid bearings in solid housing
The output shaft of the BJ worm gearbox is quite firmly embedded in the apparatus house and is well suited for immediate suspension for wheels, movable arms and other areas rather than having to create a separate suspension.
Self locking
For larger equipment ratios, BJ-Gear’s worm gearboxes will provide a self-locking effect, which in many circumstances can be used as brake or as extra security. Also spindle gearboxes with a trapezoidal spindle are self-locking, making them perfect for a wide range of solutions.