TYPES OF GEAR AND THEIR USES

                               GEAR

Purpose of gears - Gears are used to transmit torque or motion from the driving shaft to the driven shaft
1) To change the direction of rotation.
2) To change the velocity ratio.
3) To get positive drive.
Types of gear
   Gears are many types are below 

                                              BEVEL GEAR - 

 1) The teeth are cut parallel to the axis of rotation.
2) Transmit power between two shaft.
Uses - in Electric screwdriver, Clock, Washing machine, Motorcycle etc.
ADVANTAGES-

 1) simple in construction
2) Easy to manufacture
DISADVANTAGE-

 1) center distance is limited.
2) Noise at high speed.

                                         HELICAL GEAR

 1) in a helical gear the teeth are cur at an angle to the axis of rotation.

 2) it MAY be used to transmit power between two parallel shaft.

 3) Helical gear run more silently than a square gear.

 used in Automobile vehicles

 ADVANTAGES- 

1) Higher load carrying 

2) Smoother 

3)less wear and tear.

 DISADVANTAGES - 

1) Generation of heat.

2) costlier than spur gear.

                                            HERRINGBONE GEARS

To avoid axial thrust two helical gears of opposite hand can be mounted side by side to cancel resulting thrust forces. Gear ratio 10:1.

USED on heavy machinery.
ADVANTAGE - 1) shaft is free from axial force
2) high power transmission capacity
DISADVANTAGES -  1) Manufacturing cost is more

                                              RAKE AND PINION

The rake and pinion can change rotary into linear movement and vice versa.
USED in Lathe carrige Drilling machine steering system etc.

                                                       BEVEL GEAR

Bevel gears are useful when the direction of a shaft's rotation needs to be changed. The bevel gear transmit motion when the shaft are at right angle to each other.
They are usually mounted on shafts that are 90 digree apart.
the teeth profile may be straight or spiral
USED in locomotive, marine, automobiles, Printing press, cooling towers, power plants, steel plants railway track inspection machine
ADVANTAGES -

 1)High speed and load
2) 1:1 velocity ratio
DISADVANTAGE - Complicated in design and manufacture

                                         
                                               WORM AND WORM SHAFT GEAR

Worm gears are used when large gear speed reductions are needed. It is common for worm gears to have reductions of 20:1 and even up to 300:1 or greater.
Used in conveyers, Lifts, Press.
ADVANTAGE- high speed reduction ratio.