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TYPES OF GEAR ( OVERVIEW ) :-

➤There are some common types of gears are as follows:-

1. Spur Gear :-

Parallel & co-planner shafts connected by gears are called spur gears. The arrangement is called Spur gearing.

                                   

           

2. Helical Gear:- 

Helical gears having their teeth inclined to the axis of the shaft in the form of a helix , since the name helical gears.

                                    

3. Herringbone Gear :- 

Herringbone Gear resemble two helical gears that have been placed side by side they are often referred as “Double Helical Gears” in the double helical gears arrangement , the thrust are counter-balanced. In such double helical gears there is no thrust loading on the bearings.

                                   

4. Bevel Gear :-

Intersecting but co-planner shaft connected by gears are called bevel gears. The gearing is known as Bevel gearing.

                                           

Bevel gears are divided further into two categories:-

a) Spiral Bevel Gear:-

In case of spiral bevel gear are quitter and can take up more load as compared to straight bevel gear.

                                 

b) Zero Bevel Gear:- 

It’s similar to straight bevel gear , but their teeth are curved lengthwise. These curved teeth of bevel gears are arranged in a manner that the effective spiral angle is zero.

                                            

5. Worm Gear :- 

worm gear are used to transmit power at 90 degree angle and where high reductions are required the axes of worm gear shaft cross in space. The shaft of worm gear lie in parallel planes & may be skewed at any angle between zero & right angle. In worm gears , one gear has screw threads due to this worm gears are quite , vibration free & smooth output. Worm gears & worm gears shafts are almost invariable at right angle.

                                               

6. Rack & Pinion :- 

A Rack is a toothed bar or a rod can be thought of as a sector gear with an infinitely large radius of curvature . Torque can be converted into linear force by mashing a Rack with a Pinion. The rack moves in a straight line such a mechanism is used in automobile to convert the rotation of steering into left to right motion of Tie rod.   

                                        

7. External Gears :-

An external gear is one with the teeth formed on the outer surface of a cylindrical or cone.

                                      

8. Internal Gears :- 

An internal gear is one with teeth formed on the surface of a surface of a cylindrical or cone.

                                   

9. Face Gear :- 

Face gear transmit power at right angle (usually) in a circular motion. Face gears are not very common in industrial application.

                                   

10. Sprocket :- Sprockets are used to run chains or belts. They are typically used in conveyor system.

                                     

➤Also we can classify the gears according to the position of axis of shafts:-

1. Parallel Gears :- a) Spur Gears

                                 b) Helical Gears

                                 c) Rack & Pinion

2. Intersecting Gears :- Bevel Gears