The document discusses different types of differentials used in automobiles. It begins by introducing the basic components and purpose of a differential, which allows the left and right wheels to spin at different speeds during turns. It then describes the key parts of a differential system and how power is transferred. The document explains how an open differential can limit traction in certain conditions, and introduces limited-slip and active differentials as alternatives that can distribute torque more effectively. It concludes by noting some other differential types like locking and automatic torque biasing differentials.
2. Introduction
• Differential is an integral part of all four wheelers
• A differential is used to allow the wheels to spin at different speeds.
• This is necessary when the vehicle turns
3. PARTS OF DIFFERENTIAL SYSTEM
• Pinion drive gear: transfer power from the drive shaft to the ring gear.
• Ring gear: will transfer power to differential case assembly.
• Spider gears:The spider gear lies at the heart of the differential and special
mention should be made about its rotation.
• Differential case assembly: Hold the gear and drive the axel.
• Rear drive axel:Transfer torque from differential assembly to the drive
wheels.
5. Working of Differential
• When turning, the inner and outer wheels have arcs of different
turning radii.
• The inner wheels travel less distance than the outer wheels.
6. • From the drive shaft power is transferred to the pinion gear first, since the
pinion and ring gear are meshed, power flows to the ring gear.
• As the spider gear is connected with the ring gear, power flows to it.
• Finally from the spider gear, power gets transferred to both the side gears.
• Due to this both of the wheels get the required rpm
7. Different Cases
The vehicle moves straight
• In this case the spider gear rotates along with
the ring gear but does not rotate on its own
axis.
• So the spider gear will push and make the side
gears turn, and both will turn at the same
speed.
8. Vehicle takes a turn(right)
• In this along with the rotation of the ring gear it rotates on its own axis.
• So the spider gear is having a combined rotation.
• When the spider gear is spinning as well as rotating, peripheral velocity at
the left side of spider gear is the sum of the spinning and rotational velocity.
• But at the right side, it is the difference of the two, sincethe spin velocity is
in the opposite direction at this side.
9.
10. OTHER FUNCTIONS OF
DIFFERENTIAL
• First is speed reduction at the pinion-ring gear assembly since the power
flow at the pinion and ring gear are the same, such a speed reduction will
result in a high torque multiplication.
• The other function of the differential is to turn the power flow direction by
90 degree.
11. Loss of traction
• One undesirable side effect of an open differential is that it can limit traction
under less than ideal conditions.
• The torque applied to each driving wheel is the result of the engine,
transmission, and drive axle applying a twisting force against the resistance
of the traction at that roadwheel.
• In the case of a standard differential in off roading or snow situations where
one wheel begins to slip or lose contact with the ground. It takes very little
torque to spin that wheel. Open differential limits total torque applied to
both drive wheels to the amount used by the lower traction wheel .
• Total torque applied to the driving wheels may be lower than the minimum
torque required for vehicle propulsion
12. Limited Slip Differential
• A limited slip differential (LSD) or anti-spin is type of traction aiding device
that uses a mechanical system that activates under centrifugal force to
positively lock the left and right spider gears together when one wheel spins
a certain amount faster than the other.This type behaves as an open
differential unless one wheel begins to spin and exceeds that threshold.
• The LSD will remain open unless enough torque is applied to cause one
wheel to lose traction and spin, at which point it will engage.
• A LSD can use clutches when engaged, or may also be a solid mechanical
connection like a locker or spool. It is called limited slip because it does just
that; it limits the amount that one wheel can "slip" (spin).
13.
14. Active Differential
• A relatively new technology is the electronically-controlled 'active
differential'. An electronic control unit (ECU) uses inputs from multiple
sensors, including yaw rate sensor, steering input angle, and lateral
acceleration— and adjusts the distribution of torque to compensate for
undesirable handling behavior like understeer.
Some more types of differentials are
• Locking Differential
• AutomaticTorque Biasing Differential
