Gears Classification and Application

8/2/2019 Gears Classification and Application

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PRESENTATION ON

Classification And Application Of

Gears


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GEAR

CONTENTS

POWER TRANSMISSION

GEAR

TYPES OF GEARS

APPLICATIONS OF GEARS


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GEAR..

Power transmission is the movement of energy

from its place of generation to a location where

it is applied to performing useful work

A gear is a component within a transmission

device that transmits rotational force to another

gear or device


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TYPES OF GEARS

1. According to the position of axes of theshafts.

a. Parallel

1.Spur Gear

2.Helical Gear3.Rack and Pinion

b. Intersecting

Bevel Gearc. Non-intersecting and Non-parallel

worm and worm gears


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TYPES OF GEARS CONT

2.According to the peripheral velocity of the gears.

(a) Low velocity-

The gears having velocity less than 3 m/s.(b) Medium velocity-

gears having velocity between 3 and 15

m/s.(c) High velocity-

gears having velocity more than 15 m/s.


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TYPES OF GEARS CONT

3. According to the type of gearing.(a) External gearing-

The gears of the two shafts mesh externally

with each other.(b) Internal gearing-

The gears of the two shafts mesh internally

with each other(c) Rack and pinion-

The gear of a shaft meshes externally and

internally with the gears in a straight line


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TYPES OF GEARS CONT

4. According to the position of teeth on the gear

surface.

(a) Straight,

(b) Inclined, and

(c) Curved.


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SPUR GEAR

Teeth is parallel to axisof rotation

Transmit power fromone shaft to anotherparallel shaft

Used in Electric

screwdriver, oscillatingsprinkler, windup alarmclock, washing machineand clothes dryer


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External and Internal spur Gear


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Helical Gear

The teeth on helical gears are cut at an angleto the face of the gear

This gradual engagement makes helical gears

operate much more smoothly and quietly thanspur gears

One interesting thing about helical gears is

that if the angles of the gear teeth are correct,they can be mounted on perpendicular shafts,

adjusting the rotation angle by 90 degrees


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Helical Gear


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Herringbone gears

To avoid axial thrust, two

helical gears of opposite

hand can be mounted side

by side, to cancel resultingthrust forces

Herringbone gears are

mostly used on heavy

machinery.


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Rack and pinion

Rack and pinion gears

are used to convert

rotation (From the

pinion) into linear

motion (of the rack)

A perfect example of

this is the steering

system on many cars


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Bevel gears

Bevel gears are useful when the direction of a shaft'srotation needs to be changed

They are usually mounted on shafts that are 90degrees apart, but can be designed to work at other

angles as well

The teeth on bevel gears can be straight, spiral orhypoid

locomotives, marine applications, automobiles,printing presses, cooling towers, power plants, steelplants, railway track inspection machines, etc.


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Straight and Spiral Bevel Gears


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WORM AND WORM GEAR

Worm gears are used when large gear reductions are

needed. It is common for worm gears to have

reductions of 20:1, and even up to 300:1 or greater

Many worm gears have an interesting property thatno other gear set has: the worm can easily turn the

gear, but the gear cannot turn the worm

Worm gears are used widely in material handling

and transportation machinery, machine tools,

automobiles etc


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WORM AND WORM GEAR


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APPLICATION OF GEARS

1.Spur

Applicable to all types of trains and a wide range of

velocity ratios.

2. HelicalMost applicable to high speeds and loads, also used

whenever spurs are used.

3.Crossed HelicalRelatively low velocity ratio; low speeds and light

loads only. Any angle skew shafts


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APPLICATION OF GEARS

4.Internal spura) Internal drives requiring high speeds and high loads;b) Offers low sliding and high stress loading;

c) Good for high capacity, long life.

d) Used in planetary gears to produce large reduction ratios.

5.Bevel

Suitable for 1:1 and higher velocity ratios and for right-angle

meshes (and other angles)

6.Worm mesh

High velocity ratio Angular meshes

High loads


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Gears Classification and Application

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