all about gears (kinds ,applications,.....)




Gears

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 major 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.


Types of Gears

Types of 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 Gears
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 Gears
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 Gears
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 Gears
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

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.
Applications
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
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

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



Sprockets

Sprockets
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

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.

Applications
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
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



Pinion Gears

Pinion Gears
A pinion gear is the smallest gear in the gear train. It is a small gear used to drive in 90 degree angle towards a crown gear in case of a differential drive.

The gear is generally at the input and handles the least amount of torque. The gear teeth cut directly into a shaft, which is then mounted on to the gear case.

The gear has the least number of teeth that are designed to mesh with a larger wheel. These gears form an important part of the differential assembly in automobiles by sending power through the axles to the wheel.

Materials Used
The gears are constructed from fine quality materials including :
  • Steel
  • Cast iron
  • Aluminum
Use of Pinion Gears
  • Trucks
  • Cars
  • Off road applications



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.
Internal Gear
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


Girth Gears

Girth Gears
Girth gears are high precision components, which are preferred over the gear less drives because of their lower initial cost, uncomplicated installment procedure and smaller functional and maintenance costs.

One of the most important mill and kiln drive systems, girth gear and pinion are generally two of the highest cost components in the complete drive assembly. In addition, the girth gears are generally the biggest physically and, because of the various measures essential to protect the high precision finishes, are difficult to store for a longer period of time.

High precision components, the girth gears are known to deliver high efficiency and their overall life depends on proper lubrication and alignment. The capital cost of girth gears is lower than others and their installation is simple and takes less time when compared to others.

Over the years, girth gear materials have made various changes on their own. These gears can be made out of various types of materials, such as cast iron, carbon steel, alloy steel, hardened steel, bronze, and more. Casting is improved with the use of full ring risering techniques. Simulation programs are installed to ensure proper solidification. New materials are used with an added benefit of increase in hardness and hence increased ratings.

Applications
Because of the high efficiency, superior performance and long service life, girth gears are used in variety of industrial applications, including:
  • Steel
  • Sugar
  • Paper and pulp


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.
External Gear
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



Cycloidal Gears

Cycloidal Gears
The term 'Cycloid Gear' is derived from Hypocycloid, which in turn means the curve traced by a point on circumference of a smaller circle, which rotates inside a larger fixed circle. This word describes the gearing mechanism inside the gear. The gears achieve speed reduction and successful torque transmission.

The teeth of the gear are specially designed for ensuring minimum wear and tear, minimum vibration and noise and also maximum power transmitting efficiency.

These gears engage multiple teeth during transmission for a steady, smooth and noiseless operation. Clocks and watches also make use of this gearing system, though now it is not as much in use.

Salient Features
  • Provide large gear ratios.
  • Have high transmission efficiency.
  • Are light weight and are not voluminous.
  • Longer life and fewer breakdowns.
  • Steady and reliable operation.
Use of Cycloidal Gears
  • Mechanical clocks
  • Automobiles







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