Differential operation and classification. Open Differential. Limited-slip Differential.

1. Final Drive

2. 1
2
𝑁1 > 𝑁2
𝜏1 < 𝜏2

3. Differential
Differential is an essential part of any four wheeled vehicle.
A differential allows wheels of a vehicle to rotate at different speeds.
This is necessary when the vehicle turns.
Need
The driven wheels are linked together so that a single engine and
transmission can turn both wheels
If there is no differential, the wheels would have to be locked
together, forced to spin at the same speed.
This would make turning difficult and hard on car: For the car to be
able to turn, one tyre would have to slip
With modern tires and concrete roads, a great deal of force is
required to make a tyre slip. That force would have to be transmitted
through the axle from one wheel to another, putting a heavy strain on
the axle components

4. Functions
Transmits the power to the wheels
Changes the direction of rotation by 90º
Acts as the final gear reduction in the vehicle, slowing the rotational
speed of the transmission one final time before it hits the wheels
Splits the engine torque two ways, allowing each output to spin at a
different speed (This is the one that earned the differential its name)

6. The drive pinion drives the ring gear which is
attached to the differential case
• When going straight ahead:
– The differential housing and its components rotate
as an assembly
– Power is transferred equally to both wheels
• When turning a corner:
– The wheels must travel at different speeds to
prevent tire scrubbing
– Differential pinion gears “walk” around slower side
gear and cause other side gear to turn faster
– The percentage of speed that is removed from one
wheel is given to the other.
Differential Operation
𝑁𝐿𝑒𝑓𝑡 > 𝑁 𝑅𝑖𝑔ℎ𝑡

7. PART’S 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.
Classification
1) Open Differential
2) Limited slip differential

8. https://youtu.be/SOgoejxzF8chttps://youtu.be/yYAw79386WI
1) Open Differential

9. DRAWBACK OF STANDARD/OPEN DIFFERENTIAL
The problem is an open diff always tries to balance
the torque.
Almost no torque is needed to spin one wheel, and
since the open differential always sends the same
amount of torque to both output shafts.

10. Limited‐Slip Differentials
• Provide more driving force to the wheel with
traction when one wheel begins to slip
• Still allow the wheels to rotate at different speeds
when turning a corner
• Are sometimes called Posi‐Traction, Traction‐Lok,
and Posi‐Units
Limited‐Slip Differential Designs
(i)Clutch pack type
– It uses two sets of clutches, each consisting of
steel plates and friction plates
– The steel plates are splined to the differential
case and the friction plates are splined to the side
gears
– During cornering, the plates slip, allowing the
wheels to turn at different speeds
https://youtu.be/WeLm7wHvdxQ

11. (ii) Cone‐type
– It uses two cone clutches with one cone that has
frictional material on its outer surface and the other
with a grooved surface on the inside
– Cones allow wheels to turn at different speeds during
cornering, while providing torque to both wheels
during straight‐ahead driving
(iii) Gerodisc‐type
-It uses a clutch pack and a hydraulic pump
– The pump is driven by the left axle shaft
– The pump’s output determines how much pressure is
applied to the clutch pack
– The amount of tire slip determines the pressure
delivered by the pump