Fluid Flywheel notes PPT

FLUID FLYWHEEL:

DEFINE:

 A fluid coupling or hydraulic coupling is a hydrodynamic device used to transmit rotating mechanical power.

  It has been used in automobile transmissions as an alternative to a mechanical clutch.

    It also has widespread application in marine and industrial machine drives, where variable speed operation and controlled start-up without shock loading of the power transmission system is essential.

It is also known as fluid clutch or fluid coupling which couples the driving member with driven member through a medium of fluid.

It consists of two members in which one is driving member and other one is driven member.

Among them the driving member is connected with the engine flywheel and the driven member is connected to the driven member is connected with the transmission shaft.

ž         These two members are not made to contact with each other.

ž      The driven member is free to slide on splines provided on the transmission shaft.

ž      The two rotors are filled with fluid of require viscosity.

ž      Radial ribs are provided to form a number of passages to avoid the formation of eddies.

ž      They also guide the fluid to flow in the desired direction. 

WORKING:

  žWhen the engine is started, the driving member called “impeller” starts to move inside the house containing    oil.

ž  Pockets of moving driving member are completely filled with oil.

ž  Due to this, centrifugal force forces the oil outward radials.

  žThe pockets are designed in such a way that the splashed oil will strike the pockets or vanes of the driven member.

ž Hence it is forced to move in the same direction.

 žWhen the engine speed increases the oil which is coming out from the pocket of the driving member strikes the pockets of the driven member with great force.

 žThus it tends the driven member to rotate at the same speed.

ADVANTAGES:

žGives smoother power take up than the centrifugal type

when the engine is accelerated.

žNo need of separate pedal or lever to operate.

žThere is no wear on moving parts.

žNo need of adjustment is required.

žNo maintenance is necessary, except maintaining oil level.

žSimple in design

žThere is no jerk on transmission when the gear engages.

žNo skills required to operate

DIS ADVANTAGES:

1.  There is a drag on the gearbox shaft even the slip is 100%

2.  Gear changing is difficult in ordinary crash type gearbox. By using epicyclical gearbox to avoids this difficulty.

APPLICATIONS:

1.  Industrial
2.  Rail Transportation
3.  Automotive
4.  Aviation