:: Topic ::

Group no :- 3 Computer Evening Shift

~ Adarsh Patel (14)~ Bijal Khambhati (15)~ Ankur Kakrecha (17)~ Siddharth Gikwad (18)~ Feny Shakujiwala (19)~ Krish Mehta (21)

Belt drives

Contains ::

Chain drives

Shaft and axel

Friction drives

Gear drives

:: Shaft and axel ::

~ TRANSMISSION SHAFT It is used to transmit power between source and machine absorbing power EX. - line shaft, counter shafts

~ MACHINE SHAFT It is integral part of the machine itself EX. - crank shaft, cam shaft in auto mobile

:: Belt drives ::Belt drives are one of the common methods generally used whenever power or rotary motion is required to transmit between two parallel shafts.

Types of Belt drives :: Open belt drive Cross belt drive Quarter turn belt drive

Belt drive with idler pulley

Compound belt drive

Cone pulley drive Fast and loose pulley drive

Open belt drive Cross belt drive

idler pulleyCompound belt drive

Types of Belts ::~ Flat belt It has rectangular cross section.It is used when a large distance between shafts.

~ Circular belt It is known as rope belt also.It is used when a distance between two pulley are more than 8 meters.

~ V - belt It has trapezoidal cross section.It is used when a drive has relatively short distance and transmit large power.

~ Timing belt This belts are modification of flat belts.On flat belt teeth moulded.It is used when a drive has relatively short distance and transmit high power.

:: Chain drives ::Chain drive are positive drives there is no slip, and thus velocity ratio will remain constant.A chain drive are suitable for small centre distance it can be up to 3 meter.Chain drives are used for power transmission in bicycle, motor cycle, rolling mills, machine tools etc.

TYPES OF CHAIN DRIVE :

~ Roller chain~ Silent chain

~ Silent chainIt is inverted tooth chain which is used for smooth and noiseless operation at low speed.

~ Roller chainIt is commonly used in bicycles, motor cycles, machine tools etc.

:: Friction drive ::Friction drive is used for light load transmission between parallel shafts or intersecting shafts.

It consist two wheel with their friction surface.

The driving wheel drives the driven wheel by virtue of friction between them.

:: Gear drive ::

Gear drive is a very important drive in mechanical power transmission. Gear drive is positive drive.

Gear is a toothed wheel with the teeth cut on the periphery of a cylinder or a cone. Gear are mounted on the shafts with key. There are two gears mounted one is driving other is driven .

Gear drive is used to transmit power between shafts that are parallel, intersecting or neither parallel nor intersecting.

:: Types of gears ::

~ Spur gearsIf teeth of the gear wheel are parallel to the axis of wheel as shown in figure the gear are called spur gear.

USESThey commonly used in machine tools and automobile gear boxes.

~ Helical gearsThe teeth of the gear are helix around the gear. The helical gear run more smoothly and more quietly at high speed and curvilinear contact of gear teeth giving gradual engagement.

USESGenerally it is used in automobile power transmission.

~ Spiral gearsTeeth of spiral gear are as same as helical gears and it cut along helical path.

USESIt is used to transmit power between two non-parallel, non-intersecting shafts.

~ Bevel gearsBevel gear teeth are varying in cross section along the tooth width. The axis of two moving gears are inclined in the bevel gear. USESWhen the axis of the two shafts are inclined and intersect each other.

~ Worm and worm wheelA worm has one or more number of helical threads of trapezoidal shape cut on it.

USESTo transmit power between two shafts having their axis at right angles and non-coplaner. Like in drilling machine.

~ Rack and pinion Rack is a spur gear of infinite diameter. The rack is mesh with another small gear known as pinion. USESIt is used to convert rotary motion into linear motion.Such as lathe , drilling , planning machines.