What Is a Reduction Gearbox?
Reduction gearboxes, also known as torque multipliers or speed reducers, are employed to reduce the output speed of the motor. Reduction gearboxes are very simple to manufacture, such as a gear train between a motor and machinery.
The ratio of the outputs to the input gear is such that it allows the output shaft to move more slowly, thereby supplying increased torque and reduced speed.
Some types of reduction gearboxes operate as a gear train between different parts, but regardless of complexity, a reduction is possible because the output section has more teeth than the inputs section, allowing the outputs gears to move more slowly. Speed decreases, and torque increases.
Inputs velocities can be monitored with speed reducers so that the output is the correct torque & speed. Therefore, choosing the right speed reducers is an essential aspect of using them. To ensure function, it is important to find the best speed reducer for the application.
Here is a free checklist Speed Reducer Purchase Checklist that will guide you through the process of meeting your needs with the information you need in your application to allow your supplier to turn it into a reality.
This guide will help you choose the reductions gearbox:
- Speed & duty cycle
- Applications specific details
- Input/outputs requirements
- Shock & loading influences on the service factors
- Housing details
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Definition of a Reduction Gearbox:
The Reduction gearboxes are a familiar term to many people, but what does it really mean? On the surface, it may seem like devices are being “reduced” in size or quantity, which is almost true. Once rotary device such as engines or electric motor needs to reduce the output speed and/or increase the torque, gears are usually employed to achieve the appropriate result.
The gear “reduction” refers specifically to the velocity of the rotary system; The rotational speed of the rotary tool is “reduced” by varying gear ratios greater than 1:1. Gear ratios greater than 1:1 are achieved once with a smaller gear (reduced size) with a smaller number of teeth & a larger section moving with greater numbers of teeth.
Reduction gears are configurations by which inputs velocities with equal or greater output torque can be reduced to require a slower output speed. The reduction gearbox assembly consists of a set of moving gears with wheel work.
The wheel function transfers high-speed incoming movement to an arrangement of rotating gears, in which torque or motion is changed. The number of gears used in a reduction gearbox is based on the output speed requirement of the case. A reduction gearbox is commonly referred to as a reduction gear assembly.
Gear reductions have the opposite effect on torque. The output torque of the rotary system can be increased by improving the torque by the gear ratio, reducing some efficiency waste. While in many cases, gear reduction reduces speed and increases torque, in other applications, gear reduction is applied to develop speed and reduce torque.
Generators in wind turbines apply gears reduction, in these cases, to convert a relatively slow turbine blade velocity to a great speed capable of producing electricity. These applications employ reductions gearbox, which is assembled as opposed to cases that control speed and increase torque.
How to gear reduction is achieved is another main question. Several reducer forms are capable of achieving gear reduction, including, but not limited to, parallel shaft, right-angle, & planetary worm gearboxes. In a parallel shafts reduction gearbox or reducer, a pinion gear with a particular number of teeth is used and drives another gear with more teeth.
The “reductions” or gears ratios are evaluated by dividing the numbers of teeth into the larger sections by the number of teeth on the smaller side. For example, if an electric device drives a 13-tooth pinion gear that meshes with a 65-tooth section, a 5:1 reduction is obtained (65/13 = 5).
If the speed of the electric device is 3,450 rpm, the reduction gearbox reduces this velocity five times to 690 rpm. If device torque is ten lb-in, the gearbox improves this torque by a factor of five to 50 lb-in before subtracting device efficiency waste.
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Why Is a Reduction Gearbox Used?
To know why reduction gearboxes are used in a particular system, we will take the example of a ship employing high-speed turbines. It is the main requirement of a ship that in order to have suitable efficiency, the steam turbine must perform at a relatively high range of RPM, although the effective operation of the propeller requires a relatively low RPM condition.
For this reason, a reduction gearbox is implemented, which reduces the high-speed rotation of the steam turbine to the low rpm level required by the propeller. Go here to see the various applications of the Reduction Gearbox.
Also, Read: What Is a Synchromesh Gearbox? | Principle of Synchromesh Gearbox | Construction of Synchromesh Gearbox | Working of Synchromesh Gearbox
Types of Reduction Gearbox:
There are generally two types of reductions gearboxes:
#1. Single Reduction Gearbox
This assembly consists of only one pair of gears. Reduction gearboxes include the ports through which the engine shaft and propeller shaft enter the assembly. Small gears, defined as pinions, are carried by the oncoming engine shaft.
The pinion drives a great gear connected directly to the propeller shaft. The ratio of speed adjustment is controlled by proportional to the diameter of the gear and the pinion. In general, single gear arrangements includes a gear twice the size of the pinion.
#2. Double Reduction Gearbox
Double reduction gearboxes are generally used in cases with very high speeds. In this assembly, the pinions are mounted on the inputs shaft employing a flexible coupling. The pinion is firsts attached to an intermediate section defined as the reduction gear.
The first reduction gears are then attached to the low-velocity pinion using another shaft. This pinion is mounted directly on the second reduction section attached to the propeller shaft. Such an assembly facilitates reducing speed in a ratio of 20:1. There are other types of reduction gearboxes available in the market to be used in specialized applications.
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Magnetic Reduction Gearbox:
Magnetic gears reducers or magnetics reduction gearboxes can advantageously replace ordinary gear reducers to guarantee torque and speed control by applying magnetic attraction rather than physical touch between moving components.
To date, complex arrangements, low torque, and high weights have slowed the spread of this magnetic process. Magnetic gears remove the need for lubrication and therefore reduce maintenance costs. There is no need for lubrication; this also means that the equipment can perform at extremes temperatures currently used from -200˚C to 350˚C.
These benefits are particularly important for cases with high maintenances costs or for those operating in extremes conditions such as satellites & other aerospace equipment.
Along with corrosion and use, wear is one of the three major factors that restrict the life and function of mechanical parts and technical equipment. With a magnetic reduction gearbox, the absence of friction not only offsets the wear of the device but also significantly impacts the service life, which can be the key to using a system that cannot be easily replaced.
Materials detached from the aircraft worn in conventional transmissions cannot be easily eliminated, which can be a major cause of contamination. Contamination is a serious, serious drawback to equipment that cannot be maintained consistently.
Also, Read: What Is a Motor Shaft? | How Shafts in AC/DC Motors Function | Common Uses of AC/DC Motors | Construction of a Motor Shaft
Parallel Shaft Reduction Gearbox:
Parallel shaft reduction gearboxes often include multiple gear arrangements, leading to system reduction. The overall gear reduction ratio is specified by correcting each individual gear ratio from each gear section.
If the gearbox includes 5:1, 4:1, and 3:1 sections, the overall ratios is 60:1 (5 x 4 x 3 = 60). In our cases above, at 3,450 rpm, the speed of the electric device would be reduced to 57.5 rpm by applying a 60:1 gearbox.
The ten lb-in electric device torque will be increased to 600 lb-in before efficiency wastes.
If a pinion gear & its mounting parts have the same number of teeth, there is no reduction, and the gear ratio is 1:1. The gear is introduced as an idler, and its primary performance is to change the direction of rotation rather than reduce speed or increase torque.
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Right-Angle Worm Reduction Gearbox:
The gear reduction ratio in the right-angle worm type is based on the number of teeth on the mating worm wheel & the number of threads or “starts” on the worm. If the worm has two start sections & the mounting worm wheel has 50 teeth, the output gears ratio is 25:1 (50/2 = 25/1).
When rotary systems such as engines or electric motors cannot supply the appropriate output torque or speed, a gear reducer can offer a good approach. Planetary, parallel shaft & right-angle worm drives are typical reduction gearbox types for implementing gear reduction.
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Planetary Reduction Gearbox:
Evaluating the gears ratios in a planetary reduction gearbox is less intuitive because it is dependent on the number of teeth of the ring gear and the sun ring gear. The planetary gears act as idlers and do not affect the gear ratio.
The planetary gear ratio is equal to the sum of the number of teeth on the ring and the sun divided by the number of sun gear teeth. For example, a planetary arrangement with a 15-tooth sun gear and the 90-tooth ring gear has a ratio of 7:1 ([15 + 90]/15 = 7).
The planetary gear arrangement can achieve a ratio between 3:1 to 11:1. If a greater reduction ratio is required, additional planetary phases can be applied.
Also, Read: Difference Between Gas Turbine and Gas Engine | Gas Turbine | Gas Engine | Comparative Analysis of Gas Turbines and Gas Engine
What Are the Selection Criteria for Choosing a Reduction Gearbox?
Before purchasing a reduction gearbox, there are several factors to consider, including:
A reduction gearbox is employed to optimize the characteristics, speed, and torque of a mechanism’s output and input axes. So you need to know the rotation speed and torque. Therefore, it is worth asking yourself about the torque aspects.
Reducers improve the torque of the motors and therefore allows receiving member to move under the influence of a new torque. Reduction gearbox manufacturers sometimes indicate the maximum and minimum torque represented in Newton-meters (Nm) that can be supplied by each of their parts. The torque densities change depending on the gear reducer.
For example, a planetary reduction gearbox has a high torque density. The second purpose of using a gear reducer is to reduce the speed of the motor. Therefore, we recommend that you consider the correct reduction ratio for your application.
According to the rotational speed of the motors, the reduction ratios are used to identify the output rotational velocity. This information is also provided by the constructors on their product pages. It is expressed in revolutions per minute (RPM).
In the end, you should ask yourselves what type of reduction gearbox is best suited for your application. The output and inputs shafts of your reducer can be parallel-shaft, coaxials, or orthogonal. It is based on your intended use.
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Frequently Asked Questions (FAQ)
A reduction gearbox, or speed reducer, is used to reduce the speed of the input, from the motor, while also multiplying the torque the input creates.
Reduction Gear Ratio
The “reduction” or gear ratio is calculated by dividing the number of teeth on the large gear by the number of teeth on the small gear. For example, if an electric motor drives a 13-tooth pinion gear that meshes with a 65-tooth gear, a reduction of 5:1 is achieved (65 / 13 = 5).
A reduction gearbox, or speed reducer, is used to decrease the velocity of the input from the motor while also improving the torque the input produces. The device is applied to transform the output shaft revolutions of the basic engine to those needed to move the propeller.
Motor Reduction Gearbox
A reduction gearbox, or speed reducer, is used to reduce the speed of the input, from the motor, while also multiplying the torque of the input created.
Single Reduction Gearbox
We will inspect a single reduction gearbox before delivery, please rest assured to trade! single reduction gearbox from China.
Speed Reduction Gear
A Speed reducer, also called a gear reducer, is a simple gear train between the motor and machinery that is used to reduce the speed with which power is transmitted.
Double Reduction Gear Box
A specially designed primary worm reduction unit is integrally mounted on a standard single reduction Greaves worm reducer which forms the second stage. The composite units provide the most compact and rigid arrangement for the large reduction of speed necessary for slow-moving machinery.
Right Angle Reduction Gearbox
A right-angle gearbox is a type of gearbox in which the shaft changes direction at right angles. It can be a 1 to 1 ratio or greater than one such as 2:1 or 15:1. If the ratio is 1:1 it is a right-angle drive. If the ratio is greater than 1:1 it is a right-angle speed reducer.
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