GEAR DRIVE

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 .

It transmit exact velocity ratio . It may be used to transmit large

powers It has high efficiency. It has reliable service . It has compact layout

Advantages of Gear Drive

Disadvantages of Gear Drive

The manufacture of gears require special tools and

equipment

The error in cutting teeth may cause vibration and noise during

operation .

Types of Gears

Spur Gear

Teeth is parallel to axis of rotation

Transmit power from one shaft to another parallel shaft

Used in Electric screwdriver, oscillating sprinkler, windup alarm clock, washing machine and clothes dryer

External & Internal Gear

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

Conversely, an internal gear is one with the teeth formed on the inner surface of a cylinder or cone.

Helical Gear

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

This gradual engagement makes helical gears operate much more smoothly and quietly than spur gears

Bevel Gear

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

The teeth on bevel gears can be straight, spiral or hypoid

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

Hypoid gears resemble spiral bevel gears except the shaft axes do not intersect.

Usually require some of the most viscous types of gear oil to avoid it being extruded from the mating tooth faces.

Which are normally straight cut bevel gears in motor vehicle axles.

Hypoid Gear

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 that no 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

Rack and Pinion

It is Special case of a spur gear where it is made of infinite diameter so that the pitch surface is a plane .

It is used in a lathe in which the rack transmits motion to the saddle .

Non-Circular Gear

A non-circular gear (NCG) is a special gear design with special characteristics and purpose.

Textile machines, potentiometers, CVTs (continuously variable transmissions), window shade panel drives, mechanical presses, high torque hydraulic engines.

Crown Gear

A crown gear can only mesh accurately with

another bevel gear

Sun and Planet Gear

A gear train having a relative motion of axes is called a planetary or an epicyclic gear train

Important application of epicyclic gears are in transmission, computing devices, wrists watches, hoists, back gear of lathe etc.

Harmonic Drive Gear

Is a special type of mechanical gear system that can improve certain characteristics compared to traditional gearing systems

typically used in industrial motion control, machine tool, printing machine, robotics and aerospace.

for gear reduction but may also be used to increase rotational speed, or for differential gearing.

1. Grease lubrication Grease lubrication is suitable for any gear system that is open or enclosed, so long as it runs at low speed.

2. Splash lubrication Splash lubrication is the normal method for lubricating spur, helical, bevel and worm gears.

3. Spray lubrication For the higher speed units (10 to 20 m/s peripheral speed)

Lubricant for Gear