The document discusses different types of automotive differentials, which are mechanical gear assemblies that allow the left and right wheels of an axle to rotate at different speeds. It describes open differentials, locked differentials, electronic/active differentials, limited slip differentials, and their key components and functions. Open differentials evenly distribute torque to both wheels but can cause loss of traction. Locked differentials lock both wheels to rotate together, improving traction but restricting turning. Limited slip differentials improve traction over open differentials using clutch packs, cones, or torque-sensing mechanisms.

1. AUTOMOBILE
DIFFERENTIAL
UNIT
A MECHANICAL GEAR ASSEMBLY UNIT WHICH PROVIDE
DIFFERENT
SPEED/TORQUE TO SAME AXLE WHEELS
By:
Parth vaishnav
Udit kamboj

2. REQUIREMENT
•
Transfers power from driveshaft to the wheels
•
Provides final gear reduction
•
Splits amount of torque going to each wheel
•
Allow the wheels to rotate at different speeds in
turns

3. TYPES
•
Open Differential
•
Locked Differential
•
Active/Electronic
Differential
•
Limited Slip Differential

4. OPEN DIFFERENTIAL
•
These are commonly used differential to achieve Different Speeds at
wheels of the same axle
•
Application includes normal passenger car and bus

5. OPEN DIFFERENTIAL TYPICAL PARTS
•
Pinion Drive Gear: Transfers power from the driveshaft to the ring gear
•
Ring Gear: Transfers power to the Differential case assembly
•
Side/spider gears: Help both wheels to turn independently when turning
•
Differential case assembly: Holds the Ring gear and other components
that drive the rear axle
•
Rear drive axles: Steel shafts that transfer torque from the differential
assembly to the drive wheels
•
Rear axle bearings: Ball or roller bearings that fit between the axles and
the inside of the axle housing
•
Axle housing: Metal body that encloses and supports parts of the rear
axle assembly

6. OPEN DIFFERENTIAL SCHEMATIC

7. OPEN DIFFERENTIAL IMAGE

8. LOCKED DIFFERENTIAL
These are used to achieve Different Torques at wheels of the same axle
•
Locking means joining the two independent pinion gear
•
Application includes race car and off-road vehicles and 4 Wheel Drive

9. LOCKING DIFFERENTIAL NECESSITY
•
To provide increased traction compared to
the normal differential unit
CASE :
•
When one rear axle wheel is stuck in the mud,

Open differential will concentrate in
rotating the stuck wheel

Locked differential will push the vehicle
with the help of torque available at the
free wheel

10. ACTIVE/ELECTRONIC DIFFERENTIAL
(Both Open & Locked)
•
Dynamically Locking the differential
using a electromagnetic clutch
•
When cornering, the inner and outer
wheels rotate at different speeds,
because the inner wheels describe a
smaller turning radius. The electronic
differential uses the steering wheel
command signal and the motor speed
signals to control the power to each
wheel so that all wheels are supplied
with the torque they need

11. LIMITED SLIP DIFFERENTIAL
•
A limited slip differential (LSD), is very similar to the open
differential unit but has additional link that prevents wheel spin and
loss of traction
•
The standard differential delivers maximum torque to the wheel with
minimum traction. The limited slip differential delivers maximum
torque to the wheel with maximum traction
•
It is mainly used in off road vehicles
•
TYPES :
i. Clutch Pack
ii. Cone Clutch
iii. Torsen

12. LIMITED SLIP DIFFERENTIAL - CLUTCH
•
The clutch pack limited slip differential uses a set of friction discs and steel
plates to lock the axles together whenever one drive wheel experiences
uncontrolled slippage. The friction discs are sandwiched between the steel
plates inside the differential case. The friction disc is splined and turns
with the differential side gears. The steel plates turn with the differential
case.
•
Springs (bellville springs, coil springs, or leaf springs) force the friction disc
and steel plates together. As a result, both rear axles try to turn with the
differential case.
•
Spring force and thrust action of the spider gears applies the clutch pack.
Under high torque conditions, the rotation of the differential pinion gears
PUSHES OUT on the axle side gears. The axle side gears then push on the
clutch discs. This action helps lock the disc and keeps both wheels turning.

13. LIMITED SLIP DIFFERENTIAL - CLUTCH

14. LIMITED SLIP DIFFERENTIAL – CLUTCH WORKING
•
When driving normally, the vehicle can turn a comer without both
wheels rotating at the same speed.
•
As the vehicle turns a corner, the inner drive wheel must slow down.
•
The unequal speed between the side gears causes the side gear
pinions to walk around the side gears.
•
This walking will cause the outer axle shaft to rotate faster than the
differential case, allowing the pinion shaft on the side to slide down a
V-shaped ramp.
•
This action releases the outer clutches causing the clutch pack to slip
when the vehicle is turning.

15. LIMITED SLIP DIFFERENTIAL - CONE
•
A cone clutch limited slip differential uses the friction produced by
cone-shaped axle gears to provide improved traction. These cones fit
behind and are splined to the axle shafts. With the axles splined to
the cones. the axles tend to rotate with the differential case. Coil
springs are situated between the side gears to wedge the clutches
into the differential case.
•
Under rapid acceleration or when one wheel loses traction. the
differential pinion gears, as they drive the cones, push outward on
the cone gears. This action increases friction between the cones and
case, driving the wheels with even greater torque.

16. LIMITED SLIP DIFFERENTIAL - CONE

17. LIMITED SLIP DIFFERENTIAL – CONE WORKING
•
When a vehicle goes around a corner, the inner drive wheel must slow
down.
•
The unequal speed between the side gears will cause the side gear pinions
to walk around the side gears.
•
This walking action causes the outer axle shaft to rotate faster than the
differential case. Because the cones have spiral grooves cut into their
clutch surfaces, the inner cone will draw itself into the case and lock tight
and the outer cone clutch will back itself out of the case.
•
This action allows the outer drive axle to free wheel.
•
The end result is the majority of the engine torque is sent to the inner
drive wheel.

18. LIMITED SLIP DIFFERENTIAL - TORSEN
•
Torsen differentials can be used in one or more positions on a motor
vehicle:
•
Center - used to apportion appropriate torque distribution between front
and rear axles on an all-wheel drive vehicle.
•
Rear - used to apportion appropriate torque distribution between left and
right sides in rear axles. This may be on either a rear-wheel drive or four-
wheel drive vehicle.
•
Front - used to apportion appropriate torque distribution between left
and
right sides in front axles. This may be on either a front-wheel drive or four-
wheel drive vehicle.
•
A four-wheel-drive vehicle, for example, may use either one, two, or three
Torsen differentials.

19. LIMITED SLIP DIFFERENTIAL - TORSEN

20. LIMITED SLIP DIFFERENTIAL – TORSEN WORKING
•
The Torsen differential works just like a conventional differential but can lock up if a
torque imbalance occurs, the maximum ratio of torque imbalance being defined by the
Torque Bias Ratio (TBR).
•
When a Torsen has a 3:1 TBR, that means that one side of the differential can handle up
to 75% while the other side would have to only handle 25% of applied torque.
•
During acceleration under asymmetric traction conditions, so long as the higher traction
side can handle the higher percentage of applied torque, no relative wheel spin will
occur.
•
When the traction difference exceeds the TBR, the slower output side of the differential
receives the tractive torque of the faster wheel multiplied by the TBR; any extra torque
remaining from applied torque contributes to the angular acceleration of the faster
output side of the differential.

21. DIFFERENTIAL PROBLEMS
•
Bearings, humming sound gets louder
with
higher speeds
– Clean the bearing setup if persist change it
•
Ring and Pinion, show up as whining or
howling noise that changes when going from
acceleration to deceleration
•
Lack of service or low fluid can cause this
problem. Fill proper lubricant oil to avoid it

If backlash (clearance) between ring gear and
pinion gear is too great. Adjust gear and pinion
to avoid the noise
BEARING
RACK & PINION

22. Thank you !