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Monday, April 3, 2017

Types of gear and their applications


Gears are Power transmission elements. It is the Gears that decides the torque, speed, and direction of rotation of all the driven machine elements. Broadly speaking, Gear types may be grouped into five broad categories. They are Spur, Helical, Bevel, Hypoid, and Worm. A lot of intricacies are there in the different types of gears. Actually, The choice of gear type is not a very easy process. It is dependent on a number of considerations. Factors that go into it are physical space and shaft arrangement, gear ratio, load, accuracy, and quality level.

Gears may also be classified according to the position of axis of shaft:
  1.Spur Gear
  2.Helical Gear
  3.Rack and Pinion
b. Intersecting
  Bevel Gear
c. Non-intersecting and Non-parallel
  worm and worm gears

A number of gears are manufactured using different materials and with different performance specifications depending on the industrial application. These gears are available in a range of capacities, sizes and speed ratios, but the main function is to convert the input of a prime mover into an output with high torque and low RPM. These range of gears find use in almost every industry right from agriculture to aerospace, from mining to paper and pulp industry.
Some of the popular types of gears in use are :

Spur Gears

Spur Gear

Spur gears are straight-toothed gears having radial teeth used to transmit power and motion between parallel axes. These gears are widely used for speed increase or reduction, high torque, resolution for positioning systems.

These gears can either be mounted on a hub or a shaft. The gears are available in different size, design, shape and also offer a variety of features and functions to cater to different industrial requirements.

Materials Used
Spur gears are fabricated from superior quality materials, like: 

  • Metal- steel, cast iron, brass, bronze and stainless steel.
  • Plastic- acetal, nylon and polycarbonate.
Materials used to manufacture these gears are used keeping in mind certain factors including design life, power transmission requirements, noise generation.

Important Specifications to be Considered 

  • Gear center
  • Bore diameter
  • Shaft diameter
Use of Spur Gears
These gears find wide application in a number of fields including : 

  • Automobiles
  • Textiles
  • Industrial engineering

Bevel Gears

Bevel Gear

Bevel gears are mechanical devices used for transmitting mechanical power and motion. These gears are widely used for transmitting power and motion between nonparallel axes and are designed to transmit motion between intersecting axes, generally at right angles. The teeth on bevel gear can be straight, spiral or hypoid. The gears are suitable when the direction of a shaft's rotation needs to be changed.

Materials used
Materials used to manufacture these gears are used keeping in mind certain factors including design life, power transmission requirements, noise generation. Some of the important materials used are :

  • Metal - Steel, cast iron and stainless steel.
  • Plastic - Acetal and polycarbonate.
Important specifications to be considered 
  • Gear center
  • Bore diameter
  • Shaft diameter
Use of Bevel Gear
These gears find wide application in a number of fields including : 

  • Automotive industry
  • Textile industry
  • Industrial engineering products

Helical Gears

Helical Gears

Helical gear is a popular type of gear having its teeth cut at an angle, thus allowing for more gradual and smoother meshing between gear wheels. The helical gears are a refinement over spur gears.

The teeth on helical gears are specially cut at an angle, so as to face the gear. As two teeth on the gear system engage, it starts a contact on one end of the tooth which gradually spreads with the gear rotation, until the time when both the tooth are fully engaged.

The gears are available in different sizes, shapes and designs to meet the customer specifications.

Materials Used
These gears can be manufactured from superior quality materials including stainless steel, steel, cast iron, brass etc. depending on the application.

Use of Helical Gears
These gears are used in areas requiring high speeds, large power transmission, or where noise prevention is important. 

  • Automobiles
  • Textile
  • Aerospace
  • Conveyors

Worm Gears

Worm Gear

Worm Gear

A worm gear is a type of gear, engaging with a worm to significantly reduce rotational speed, or allowing higher torque to be transmitted. The gear can achieve a higher gear ratio than spur gears of the same size.

Materials Used
Worm gears can be constructed from a number of materials depending on the end application. Some of the popularly use materials are : 

  • Brass
  • Stainless steel
  • Cast iron
  • Aluminum
  • Hardened steel
The gears can operate under difficult conditions and have the ability to achieve large speed reductions. The gears also transmit high loads at high speed ratios.

Types of Worm Gears 

  • Non-throated
  • Single-throated
  • Double-throated
Use of Worm Gears
These gears find application in : 

  • Electric motors
  • Automotive components

Differential Gears

Differential Gear

Differential gears are referred to an arrangement of gears, connecting two axles in the same line and dividing the driving force between them. One axle is allowed to turn faster than the other. These gears are often used in automotive industry for allowing a difference in axle speed on curves.

In automobiles, the gear system allows the wheels to rotate at different speeds and simultaneously supplying each of them with equal torque. The gears are specially designed to create a differential and consist of pinion and turnable gears.

Types of Differential Gears 

  • Straight Line Differential Gears
  • Rotary Differential Gears
Materials Used
The gears are manufactured using materials including : 

  • Aluminum alloys
  • Cast iron
  • Stainless steel
Use of Differential Gears
The gear is extensively used in the automobile industry for effective and efficient working of vehicles. These gears do not create noise and also help in speed differential.

Ground Gears

As generally seen grinding is most of the time conceived in context of quantity fabrication of superior quality gears as a form of secondary refining procedure. We incline to forget that grinding is essentially a basic process in the step towards production of case hardened gears. Moreover, the teeth of precision-engineered fine-pitch gears completely ground from the blank itself.

The advent of trawling also led to the development and manufacturing of Ground Gears. Ever since then ground gears have made substantial improvement in the terms of designing and component accuracy. These gears assure high transmission accuracy and deliver superior efficiency, greater load capacity, and correction of profile and durability.

Ground gears can be made using different materials, such as cast iron, carbon steel, alloy steel, hardened steel, bronze, and more.

Advantages of Ground Gears 
Ground Gears offer various advantages to its users, some of which are: 

  • High Precision: Achieving high precision is not a difficult task for ground gears since in the grinding process, there is little removal of material in the final pass.
  • Superior Surface Finish: Grinding makes the surface of ground gears more shiny than that obtained from any other machining technique.
  • Improved Flexibility: Hardened steel alloys can be used to developed into ground gears that gives its added flexibility.
  • Minimal Surface Stress: There is minimum residual surface stress in ground gears.
  • Load Carrying Capacity: Ground Gears exhibit a higher load carrying capacity.
  • Minimal Wear and Tear: Ground gears have minimal wear and tear that results in prolonged life.
Limitations of Ground Gears
Though ground gears offer multiple benefits and advantages, they too have some limitations: 

  • There is a limit to grinding procedures and that is to ferrous material.
  • Hard metals can be grind in an efficient and better way than the soft ones.
  • In case of worm or helical gears, grinding may not be the ideal solution. This is due to the reason that it often involves deviations in terms of removal and profile.
  • Gear grinding machines are not as popular as hobbing machinery.
  • Grinding demands higher costs, as it is a secondary operation.
These gears find wide application in a number of fields including : 

  • High Speed Rotation: Ground gears are ideal for uses in applications that need noise and vibration resistance in the case of high-speed gear drives. An example can be that of ground spur gears.
  • Positioning: CP Racks and Pinions are recommended for perfect positioning applications. In these cases, ground gears are used in calculating for reducing pitch errors.

Kiln Girth Gears

Kiln Girth Gears

Kiln girth gears are large diameter / large module gears that are manufactured using large gear cutting machines. The girth gear of a rotary kiln comes with a diameter of 6384 mm with 56 module and 112 teeth. These gears are very difficult to fabricate using the conventional techniques of gear cutting. In manufacturing of these gears, teeth cutting is done using face mill cutter on a horizontal boring machine, which generally reduces the time taken in teeth cutting to one-third of the original one.

The kiln girth gears come under the category of industrial gears and the commonly used material for these gears is 42 Cr Mo 4. These gears are widely used in cement industry, sugar industry and other industrial purposes and applications.

Engineered to precision, kiln girth gears are known to deliver superior efficiency and flawless performance and their overall life depends on proper alignment and lubrication. These gears are easy to install and take less time as compared to others.

Industrial Applications
Some of the important applications of girth gears include:

  • Heavy Machinery Industries
  • Metal Casting Industries
  • Metal Processing Industries
  • Construction Industries

Precision Gears

Precision gears are custom-made actuators that can be designed for varying uses and applications. These gears are generally used in applications under conditions of light loading. Precision gears are generally preferred for their precise, smooth, compact, noiseless and reliable performance.

Precision gears can be manufactured as per the customer's drawings or based on a functional description depending on the type of application. The different types of precision gear products include, - spur gears, helical gears, worm gears, anti-backlash gears, cluster gears, clutch gears, face gears, planetary gears, gear assemblies, gear boxes, bevel gears, miter gears, metric gears, internal gears, idler gears, gear rack & pinion, worms, worm shafts, splines, spline shafts, se shafts, and more. These gears can be manufactured as per the exact customer specifications or according to application need.

The quality and performance of a precision gear depends on the quality of blank in which it is cut. Thus it is essential to hold tight tolerances without grinding.

Precision gears are known for their trouble free superior performance, long service life, and excellent surface finish and customization capability. These gears are used in a variety of industrial applications, such as heavy machinery Industry, metal casting, metal processing, construction, and more. 

Rack Gears

A rack is generally used for converting rotational motion into linear motion. It is a flat bar onto which the teeth of a pinion gear are engaged. It is a kind of gear whose axis is at infinity. These gears are designed to accommodate a wide variety of applications.

Materials Used
A variety of materials are used keeping in mind the application. Some popularly used materials are : 

  • Plastic
  • Brass
  • Steel
  • Cast Iron
These gears ensure quieter and smoother operation. The mechanism provides less backlash and greater steering feel.

Use of Rack Gear
The gear is commonly used in steering mechanism of cars. Other important applications of rack gears include : 

  • Construction equipment
  • Machine tools
  • Conveyors
  • Material handling
  • Roller feeds


A sprocket is a gear having metal teeth that meshes with a chain. Also known as a cog wheel, it is a small toothed ring that can fit onto the rear wheel. It is a thin wheel having teeth that engage with a chain.

Materials Used
A variety of materials can be used to manufacture superior quality sprockets used in different industries. Some of the materials used are : 

  • Stainless steel
  • Hardened steel
  • Cast iron
  • Brass
Use of Sprockets
This simple gear finds application in diverse areas including : 

  • Food industry
  • Bicycles
  • Motorcycles
  • Cars
  • Tanks
  • Industrial machines
  • Movie projectors and cameras

Segment Gears

The segment gear, as the name suggests, is basically a gear wheel. These gear wheels are composed of a large number of pieces that are small parts of a circle. A segment gear is connected to the arms or trappings of the water wheel.

The segment gear comes with a part for receiving or communicating the reciprocating motion from or to a cogwheel. These gears also comprise of a sector of a circular ring or gear. There are also cogs on the periphery.

Segment Gears are available in various finishes, such as untreated or heat-treated and can be designed as a single component or as an entire system.

Segment gears, which are basically gear wheels, are used in variety of industrial uses and applications. These gears offer various advantages such as improved flexibility, superior surface finish, high precision and minimum wear and tear. Some of the uses of segment gears include:

  • Defense
  • Rubber
  • Railways

Planetary Gear

Planetary gear is an outer gear that revolves around a central sun gear. Planetary gears can produce different gear ratios depending on which gear is used as the input, which one is used as the output.

Materials Used
The gears can be constructed from a variety of materials including : 

  • Stainless steel
  • Hardened steel
  • Cast iron
  • Aluminum
The gears are suitable for reduction of high RPM electric motors for use in high-torque low RPM applications. These gears are used in precision instruments because of their reliability and accuracy.

Use of Planetary Gears
These gears are the most widely used gears having diverse applications including : 

  • Sugar industry
  • Power industry
  • Wind turbines
  • Marine industry
  • Agriculture industry

Internal Gear

An internal gear is a hollow gear with teeth cut on its internal surface. The teeth in such a gear project inwards instead of outwards from the rim.
Materials Used
There is a variety of materials being used to manufacture internal gears depending on the end application. Some of the popularly used materials are : 

  • Plastic
  • Aluminum alloys
  • Cast iron
  • Stainless steel
The teeth in such gears can either be spur or helical. The internal teeth have a concave shape with a base thicker than that of an external gear. The convex shape and a strong base help in making the teeth stronger and also creating less noise.

Advantages of Internal Gear 

  • The gears are specially designed to accommodate a wide range of equipment.
  • The gears are cost-effective and ideal for a broad range of light-duty applications.
  • The non-binding tooth design ensures smooth and quiet operation.
Use of Internal Gears 
  • Light duty applications
  • Rollers
  • Indexing

External Gear

One of the simplest and most used gear units, external gears are extensively used in gear pumps and other industrial products for smooth functioning. These gears have straight teeth parallel to the axis. The teeth transmit rotary motion between parallel shafts.
Materials Used
The gears can be constructed from a variety of materials including : 

  • Stainless steel
  • Hardened steel
  • Cast iron
  • Aluminum
The kind of material used in manufacturing these gears depends on the end use they are being put to.

Use of External Gears
These gears are used in diverse fields including : 

  • Coal industry
  • Mining
  • Steel plants
  • Paper and pulp industry Thanks

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