UNIT III GEARS AND GEAR TRAINS

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

DEFINE GEAR A circular body of cylindrical shape or that of the shape of frustum of a cone and of uniform small width, having teeth of uniform formation, provided on its outer circumferential surface is called a gear or Toothed gear or Toothed wheel.

Advantages It transmits exact velocity ratio. It may be used to transmit large power. It has high efficiency. It has reliable service. It has compact layout. Disadvantages The manufacture of gears require special tools and equipment. The error in cutting teeth may cause vibrations and noise during operation.

SPUR GEAR External and Internal spur Gear…

(c) Bevel gear (d) Spiral gear (a) Single helical gear. (b) Double helical gear. (c) Bevel gear (d) Spiral gear

2.According to the peripheral velocity of the gears Low velocity Medium velocity and High velocity 3.According to the type of gearing External gearing Internal gearing and Rack and pinion 4. According to position of teeth on the gear surface Straight Inclined and curved.

External gearing Internal gearing Rack and pinion Internal gears Rack and pinion  

SPUR GEAR

NOMENCLATURE OF SPUR GEARS