Speed Reducers

Chapter 1: Principle of Speed Reducers

This chapter will discuss what speed reducers are, the speed reduction process, and the considerations when selecting speed reducers.

What are Speed Reducers?

A speed reducer is a gear train between the motor and the machinery that is used to slow down the transmission of power. Speed reducers, also known as gear reducers, are mechanical devices that serve two roles. The primary function of a gear reducer is to duplicate the amount of torque produced by an information power source in order to increase the amount of work that can be done.

Speed reducers have two primary functions. They double the torque produced by the power source (the input) first. Second, as the name says, speed reducers reduce the input speed so that the output is the correct speed. A speed reducer's output gear has more teeth than the input gear. As a result, while the output gear may revolve more slowly than the input gear, the torque is enhanced.

Speed Reduction Process

The speed reduction (or gear reduction) process can be discussed in the context of the following aspects:

Gear Ratio

The gear ratio is a measurement of how different gear sizes interact to transfer energy. The measurement of a circle, which is a major component of gears, is the most important portion of this computation. Examining the circumference of a circle might help you understand how to calculate the gear ratio. The output speed of a gear that turns twice as fast as a larger gear has a 2:1 ratio, which means the output speed has been lowered in half.

For converting revolutions per minute (RPMs) to torque, this example simplifies more sophisticated gear reducers with numerous gear pairs in a sequence. In attaining the gear ratio, the only two gears considered are the driver gear and driven gear. Any gears that are found in between the two are not calculated in the gear ratio. A simple way to calculate the gear ratio is to count the number of teeth in the drive and driven gear. An example to consider is that the driver gear has seven teeth while the driven gear has 30. The driver gear must turn 4.3 times before the driven gear begins turning.

Driver Gear

The driving gear is the equipment that provides the energy (often called the driver). The majority of mechanical systems require the use of gears. Gears are wheel-like revolving objects with teeth around their rims. One gearwheel transfers turning motion and force to the other as the gears rotate together. In a mechanical system, gears are used to transport energy. Gear trains of two or more wheels work together to transfer rotary motion and force from one part of a complex machine to another.

Driven Gear

The driven gear is the gear to which the force is directed (often called the follower). Regardless of how many gears are in the series, they are the biggest of the gear set and come in a variety of designs.

Torque of the Speed Reducers

Torque is a rotational force that the gear reducer receives and converts into a new force and speed while maintaining the same level of power. Gear reducers are a gear or sequence of gears used to lower a motor's torque, which decreases in direct proportion to the number of spins per unit of time (or revolutions per minute) reduced. Base-mounted or shaft-mounted gear reducers do this.

The size of the gears determines how much torque is multiplied or divided by them. The ratio of gear sizes determines whether torque is increased or decreased, which is the most fundamental feature of gear box operation.

Considerations When Choosing a Speed Reducer

The considerations when choosing speed reducers include:

Torque of the Motor

A reducer boosts your motor's torque, allowing a receiving part to rotate under the influence of a new torque. Manufacturers of gear reducers list the minimum and maximum torque (in newton meters, N.m) that each of their products can handle. Depending on the gear reducer, the torque density changes. Planetary gearboxes, for example, have a high torque density.

Geometry of the Shaft Housing

The geometry of the housing, input, and output shafts is one of the most important factors to consider when choosing a gear reducer. The type of gear reducer required and how it will interface with the equipment, the motor, and the load will be determined by geometrical considerations.

Operating Hours of the Speed Reducer

Operational variables such as the needed number of operating hours and if the equipment will be exposed to harsh chemical, thermal, shock, or vibration conditions should also be addressed. For example, a gear reducer in an aggregate conveyor may be subjected to severe shock, vibration, and temperature stresses while operating for lengthy periods of time in a dirty environment.

Speed of Motor

Another function of a gear reducer is to reduce motor speed, and we recommend that you consider the best reduction ratio for your application. The reduction ratio is utilized to calculate the output rotational speed based on the rotational speed of your motor. It's measured in RPM (revolutions per minute).

Selection of Speed Reducer

Because there are so many types of gear reducers created to satisfy the requirements of a wide variety of functions and parameters, an expert, engineer, or designer who is experienced in gear reducers is required at this stage of the selection process. The input and output shaft configurations are the first factors to consider when selecting a gear reducer.

Performance of the Motor

Motors are subjected to shock or cyclic stresses in some applications. When selecting a gear reducer, it is critical to consider these factors in order for the gear reducer to cope with the higher torque.

Backlash in the Gearbox

Backlash is the amount of mistake or play in the meshing of the gears in the gearbox that causes mechanical shock when the transmission is started or stopped. To minimize premature mechanical failure in applications where the motor is driven sporadically, it may be advantageous to use a gearbox with minimal backlash, such as a planetary gearbox.

Mounting and Connection

If space and profile constraints exist in the gearbox mounting location, the gearbox's size, shape, and arrangement are critical in choosing which alternative is best. Different types of gears have different size efficiencies, with planetary gear trains being the smallest and spur gears requiring the greatest space. It may also be viable to use a gearbox that serves as the motor's mounting in smaller applications. On the other hand, larger applications usually necessitate mounting them individually on a chassis.

Chapter 2: Types of Speed Reducers

The different types of speed reducers include:

Cyclo Reducers

A cyclo reducer, also known as a cycloidal speed reducer, is a device that reduces the speed of an input shaft by a certain factor. Cycloidal speed reducers offer high ratios in a small package with extremely little backlash. Cyclo reducers work by using a round disc that rotates off center to decrease the input speed and bring it down to a more controllable level, which is beneficial or necessary for the components that receive the output. The reduction ratio, which compares the input and output speeds, is a common way to identify these systems. Cyclo reducers can achieve large reduction ratios with excellent accuracy while remaining compact; nevertheless, they are poor at producing ratios below 50:1, which other devices like shaft mounted speed reducers can't do in a single stage. Heavy-duty steel or other robust metals, such as aluminum or cast iron, are utilized to create and house them.

Material handling, automotive, aerospace, recreation, construction, food and beverage processing, oil and gas, and textile industries all employ cyclo reducers. They are widely employed in boats with propellers and assist in automation equipment, conveyors, presses, pumps, generators, and robotics. An input shaft, an eccentrically mounted bearing, a cycloidal disc, ring pins, output rollers, and an output shaft make up a cyclo reducer. The input shaft drives the bearing that rotates the disc. The disc does not rotate around a single center point since it is eccentrically mounted; instead, it rotates off center, closer to certain ring pins than others. In order to create a consistent rotation of the output shaft from the wobbling movement of the disc, output rollers fit through holes that are slightly bigger in diameter than the rollers.

The lobes along the disk's edge correspond to the ring pins attached to the chassis, except there is one more pin than the lobes, causing the cycloidal disc to rotate around the bearing faster and in the opposite direction than the input shaft. The number of ring gear pins minus the number of lobes on the cycloidal disc divided by the number of lobes on the disc, represented as R=(P-L)/L, is the ratio of the input speed as to the reduced output velocity. Cyclo reducers are comparable to other speed lowering systems such as gear drives and reduction gears, but unlike many others, the input and output shafts cannot be reversed since the disc will not revolve properly.

Gearbox Speed Reducer

A gearbox is a gear train used to change a motor's speed and torque characteristics. When gearboxes lower speed, the torque (turning force) at the output increases at the same time. They lessen torque as they gain speed. Speed reducers, also known as gearboxes or gear reducers, are enclosed mechanical devices that use gear trains to enhance the torque and lower speeds on a drive between a motor and a piece of machinery.

Gear Drives

Gear drives are pre-assembled systems that can be employed in a variety of power transmission applications. They are used to convey power to a driven piece of machinery and vary or modify that power.

Gear Motors

A gear reducer connects a motor to a driven load through a mechanical transmission system. A gearbox is another name for it. It allows you to change the torque and speed of a motor in relation to a load.

Gear Reducers

Gear reducers, also known as reduction gears, are required for high-efficiency machinery that operates at high speeds. The speed produced by the machinery must be decreased to fit the needs of the powered application in order for it to be viable. A gear reducer is made out of a large gear that is positioned next to a smaller gear, with both gears turning together. When a large gear is coupled to a single smaller gear in a single gear reducer, the smaller gear produces two revolutions for every one turn of the larger gear. There is more speed but less torque with the repeated spins of the smaller gear. The gear reduction procedure takes place at predefined ratios that match the input and output gears' characteristics. The energy shift is achieved by changing the ratio of the moving gears in a gear reducer.

In Line Gear Reducers

The RPM of the motor is transmitted to an output shaft that is parallel to the motor shaft using in-line gearboxes. The output shaft might be coaxial (aligned) with the motor shaft or offset by a small distance depending on the gear train. The following types of gears are commonly used in in-line gearboxes:

Planetary GearBox

The coaxial assembly is one of the most important features of a planetary gearbox. Planetary gearboxes are small because of this type of arrangement. Planetary gearboxes have a small footprint, great efficiency, low clearance, and a high torque-to-weight ratio. Their intricate and expensive design, on the other hand, necessitates specialist upkeep. Planetary gears are recommended for applications demanding high accelerations (robotics) as well as those requiring low speed but high torque (industrial rotary furnaces). They're also common in machining centers and other machine tools, as well as mobile machinery for public and agricultural tasks.

Herringbone Gears

Herringbone gears are made up of two helical gears positioned side by side on opposite sides. This keeps the benefits of helical gears while removing axial forces, making them suitable for applications requiring a lot of torque, such as heavy-duty power transmission.

Spur Gears

Spur gears are the most frequent gear design, and because of their uniformity, they are reasonably inexpensive. They do, however, lack the torque capability of several other gear designs.

Helical Gears

Helical gears mesh better than spur gears, making them quieter in operation and capable of handling higher torque. They do, however, produce axial forces that make them unsuitable for some very high torque applications due to their design.

Right Angle Gearboxes

Right Angle Drive Type "T" Speed Reducers are available in a range of reduction ratios from 10 to 100. Hardened steel, ground threadworms, and phosphor-bronze gears are used in these units to ensure the smoothest transmission contact possible. The worm is found at the bottom of the worm gear or underneath it.

All of these machines come with Timken bearings as standard equipment. There are five sizes to select from. Special shaft extensions are available. Right-angle gearboxes transmit a motor's RPM to an output shaft that is at right angles to the motor shaft axis (90 degrees). The following are types of right angled gearboxes:

Worm Gear Reducers

The input and output shafts of a worm gear reducer are perpendicular. They're commonly employed in situations that require a high transmission ratio. Worm gear reducers have a non-reversible mechanism. This indicates that the worm wheel is unable to propel the worm. The advantage of this non-reversible technique is that it provides the system with a higher level of security. Worm gear reducers are less expensive and quieter than planetary gearboxes.

Worm gear reducers are quieter and more comfortable to operate because they do not vibrate. Worm gear reducers, on the other hand, heat very quickly due to their small size. They also have a varying amount of performance. The performance of a worm gear reducer can be improved by combining it with additional gearboxes and gear trains.

Bevel Gear Reducers

The fundamental feature of bevel gear reducers is their angular bell crank, which allows the user to adjust the rotation system of the machine. You'll be able to switch from a transverse to a longitudinal rotation system as a result of this. Reducers with bevel gears are small. They're also strong and capable of handling a lot of power. If high torque is required this technology fulfills the criteria. Their teeth are strong enough to work with three-phase asynchronous motors, as well as synchronous and asynchronous servo motors.

Because bevel gear reducers are quiet, they are easy to use. They also have a high level of performance and are energy efficient. However, their performance is still inferior to that of planetary gearboxes. Bevel gear reducers are very costly to buy and highly demanding to maintain. Bevel gear reducers are commonly employed in high-powered conveyors, but they can also be found in agricultural and public works mobile machinery.

Magnetic Speed Reducers

By using magnetic attraction instead of physical contact between moving parts, magnetic speed reducers can effectively replace traditional gear reducers to assure speed and torque multiplication. The diffusion of this magnetic technology has been hampered by the complex assembly, high weight, and poor torque. Magnetic gears, on the other hand, do not require oil, lowering maintenance expenses. Without lubrication, mechanisms can work at severe temperatures (now tested from -200 to 350 degrees Celsius).

These benefits are especially appealing for applications with high maintenance costs or for applications operating in harsh environments, such as satellites and other aerospace devices. Wear is one of the three basic variables that limit the life and performance of mechanical components and technological systems, along with usage and corrosion. The absence of friction in magnetic reducers minimizes system wear and has a direct impact on service life, which can be critical in maintaining mechanisms that are difficult to replace.

In traditional transmissions, material that has become disconnected from the worn surface is difficult to remove, leading to contamination. Contamination is a particularly critical issue for equipment that can't be maintained regularly.

Hypoid Speed Reducers

A hypoid is a spiral bevel gear with an axis that does not meet the meshing gear's axis. A hypoid gear has a revolving hyperboloid shape (that is, the pitch surface of the hypoid gear is a hyperbolic surface), whereas a spiral bevel gear has a conical shape. Because the pinion is off-axis to the crown wheel (ring gear) with the hypoid gear, the pinion can be wider in diameter and have a larger contact surface.

In hypoid gear design, the pinion and gear are almost always of the same hand, and the pinion's spiral angle is usually greater than the gear's. The hypoid pinion has a greater diameter than a bevel pinion of equal size. A hypoid gear combines a straight-cut gear and a worm gear that involves some sliding. Hypoid gears require special gear oils due to the sliding action, which necessitates good lubrication under tremendous pressure between the teeth. Hypoid gearings are more efficient than standard worm gearing in power transmission products.

They are much more powerful since any load is distributed across numerous teeth at the same time. Bevel gears, on the other hand, are loaded one tooth at a time. Hypoid gearing's many contacts can also be practically silent if properly lubricated.

Speed Reducer Axis

The speed reducer axes include:

Orthogonal Axis

Gear reducers with orthogonal axes are bevel gear reducers with perpendicular input and output shafts. Due to poor tooth contact, orthogonal gear reducers are less exact than parallel axes gear reducers. Power branching devices are what they're called. On the job site, gear reducers with orthogonal axes are frequently utilized as power branching devices. Gear reducers with orthogonal axes have lower precision than gear reducers with parallel axes. Because the pinion is only supported on one side, it is easier to deflect, resulting in a slightly reduced transmission efficiency (98%) due to poor teeth contact. Straight bevel gear reducers have standardized reduction ratios of 1:1 and 1:2 and are appropriate for moderate rotation under 1000rpm.

Skew Axis

The gear reducer’s input and output axes are referred to as skew axes when they are offset but orthogonal to each other. Skew axes are non-intersecting and non-parallel axes with a gear centerline offset, allowing for more tooth surface contact and a higher contact ratio. Increased torque capability and smooth transmission are the end results.

Parallel Axis

The output and input shafts of parallel axis gear reducers are parallel. They have a high level of precision and efficiency in transmission. Large standard spur gears or helical gears can be used in parallel axes gear reducers. They're found in devices like cranes, elevators, and conveyors with a lot of rotation on the load side.

Chapter 3: Efficiency and Maintenance of Speed Reducers

This chapter will discuss the aspects of improving the efficiency of speed reducers. It will also discuss the maintenance of speed reducers.

Improving Efficiency of Speed Reducers

To improve the efficiency of speed reducers, consider:

Correcting Mechanical Noise Levels

Before being released on the market, gear motors should be subjected to frequency measurement tests. It's critical to pay attention to mechanical vibrations and have your gear motor provider understand how to use vibration monitoring devices to avoid unpleasant frequencies.

Torque Measurement

The appropriate measurement of the beginning torque, output torque, and rated torque ensures proper motion transmission and machine or application adaptability.

Electricity Consumption

Another factor to consider while deciding between two models is the speed reducer's energy efficiency. The location of the gear train, the location and characteristics of rolling bearings, and the surface treatments of components all help to improve overall system performance. Rolling bearings are used and placed in a variety of ways.

The use of rolling bearings in geared systems reduces friction between the multiple moving parts, resulting in significant energy savings.

Self-Lubricated Plain Bearings

Friction is reduced to a lesser amount by these parts than by rolling bearings. Despite this, they minimize axial motion-induced axial motion-induced axial motion-induced axial motion-induced axial motion-induced axial

Use of Vibration-Dampening Components

Several solutions can be applied to reduce vibrations, such as the use of rolling bearings, washers, and plain bearings. In the long term, using all of these items will increase the proper operation of the gear motor. Because of the lower vibration levels, it will be more precise, quieter, and last longer.

Maintenance of Speed Reducers

The most prevalent cause of premature gearbox failure is not the quality of workmanship for the gearbox, but rather the operating conditions and service factor for which it was intended. The most significant issue is good gearbox maintenance, which includes ensuring adequate lubrication is available in all parts of the gearbox at all times and replacing the lubricant when it runs out due to mechanical pressure and heat. In order to decrease vibration and stress, it is also necessary to properly mount the gearbox. Always check that the alignment error between the motor and the gearbox and the alignment error between the gearbox and the driven load is within the gearbox's permissible limits. Below are some of the steps taken in maintaining gear reducers.

Gear Reducer Overheating

Overheating indicates that the gear reducer is not getting enough lubricant. Overheating can be avoided by checking the surface temperature of the gear reducer on a regular basis. Overheating can be caused by a shortage of lubricant, causing friction between the gears. If the spacing between gears is too narrow or the gap is irregular, gear overheating might occur. Adjusting the gear gap that has been built can also resolve this problem. Maintaining a gear reducer properly ensures that it will continue to work for many years.

Lubrication of the Gears

Every manufacturer of gear reducers supplies or recommends the proper lubricant for their devices. To improve performance, the lubricant must have the necessary characteristics. Filtering the lubricant to remove impurities may be necessary at first during the break-in process. The lubricant's quality and level should be checked regularly.

Reducer Vibration or Noise

Noise is the first sign of a problem with a gear reducer. Operating it without a load can be used to assess it. Essentially, noise and vibration indicate that the gear reducer has to be overhauled or replaced. Disassemble the gearbox and either remove the blur together with sharp corners or the problematic gears. Disassemble the clip and adjust the gasket to the space until no clapping occurs. Keep the housing clean by cleaning the bearings and housing. Examine the housing and gears to see if they fulfill the standards.

Contamination is Reduced

The lubricant is the only thing that can be used in a gear reducer. Dust and water can cause substantial damage to gears if they enter through inadequate seals.

Storing Gear Reducers

All of the covers, vents, and drains on gear reducers are closed and sealed, and they are stored in a clean, dry, and climate-controlled environment. The lubrication cycle of the gear reducer must be maintained even when it is not in use. It should be rotated throughout the procedure to ensure even lubricant distribution.

Conclusion

Gearboxes have a number of features that influence their usefulness for various applications. When selecting a gearbox, it's critical to consider your individual application in order to find a solution that fits all of the design criteria. Once you've decided on a gearbox, it's critical to correctly install and maintain it in order to get the most out of it.

As discussed in the article, the selection, installation, and maintenance of a speed reducer are possible with the understanding that:

• A speed reducer is a mechanical system of gears arranged in such a way that the input speed can be reduced while the output torque remains the same or increases.
• When the driving gear is smaller and has fewer teeth than the driven gear, a gear reducer is used. This is in contrast to overdrive, which occurs when the drive gear is larger and has more teeth than the driven gear.
• A speed reducer is a speed reduction that uses gears, shaft placement, and gear arrangement to adjust the rotational speed. They're commonly utilized with reduction transmission technology, which combines the driving motor and the gearbox or gear reducer into a single transmission structure.
• Before selecting to buy a gear reducer, there are a few things to consider. A gear reducer's primary function is to modify the torque and speed characteristics of a mechanism's input and output axes.
• Speed reducers require and are strongly advised to be maintained on a regular basis. Failures, errors, and poor performance can be mitigated or avoided by routine assessment.