TYPES OF GEARS | GEAR | T.O.M. | MECHANICAL ENGINEERING

TYPES OF GEARS

 classification of gear  : 

1. according to position of shaft : 

 (A) *Parallel Shaft .. :- 

                                     The two parallel and coplanar shaft are connected by gears. 

EXAMPLE :- 

                    1. SPUR GEARS
                    2. HELICAL GEARS :-  ( 1. Single helical and 2. Double helical) 

1''SPUR GEARS :- 
                            The teeth are straight to shaft axis. Spur gear used to transmit the power between two parallel shaft. 

 characteristics :-

1. High power transmission .

2. easy to design and manufacturing .

3.cheap in cost compared to other. 

Limitations:-

1. Not suitable for too soft when their direction is changed
2. produce noise and stress. 

2'' HELICAL GEARS :-
                                      Teeth are twist oblique to the axis. 

Characteristics :-

1. Has higher strength compared with spur gear .

2effective in reducing noise 

3.can be used for parallel non parallel non intersecting shaft
                                      

*(B) INTERSECTING SHAFT :-

                          

                            The two non parallel or intersecting shafts connected by gears. 

Example :- BEVEL GEARS 

ONE OF PAIR OF BEVEL GEARS ARE USED TO CONNECT TWO SHAFTS WHOES AXES INTERSECT AND THE PITCH SURFACE ARE CONES. 

*(C) NON INTERSECTING NON PARALLEL 

Example :- hypoide and worm gears

.2. According to the peripheral velocity of the gears. :-

The gears, according to the peripheral
velocity of the gears may be classified as :

(a) Low velocity, 

(b) Medium velocity, and 

(c) High velocity.
 

Low velocity gears :-

The gears having velocity less than 3 m/s are termed as low velocity gears

 Medium Velocity gears :- 

The gears having velocity between 3 and 15 m/s are known as medium velocity gears.

High velocity gears :-

If the velocity of gears is more
than 15 m/s, then these are called high speed gears.

3.3. According to the type of gearing.  

The gears, according to the type of gearing may bec lassified as :

(a) External gearing,

 (b) Internal gearing, and

 (c) Rack and pinion.

External gearing :-

In external gearing, the gears of the two shafts mesh externally with each other . 

The larger of these two wheels is called spur wheel and the smaller wheel is called pinion. In

 

internal gearing :-

In internal gearing, the gears of the two shafts mesh internally with each other as shown in

). The larger of these two wheels is called annular wheel and the smaller wheel is calledp inion. 

RACK AND PINION GEARING :-

The teeth on the gear surface may be

(a) straight, (b) inclined, and (c) curved.

We have discussed earlier that the spur gears have straight teeth where as helical gears have

their teeth inclined to the wheel rim. In case of spiral gears, the teeth are curved over the rim surface