DIFFERENTIAL

LIMITED SLIP DIFFERENTIAL (LSD)

Group: Mohamed Hairi Bin Abdul Shukur (01DAD10F2060)

Khairil Azreen Bin Kholid (01DAD10F2046)

Amir Yusuf Bin Hazimi (01DAD10F2058)

Muhammad Amin Bin Yazid (01DAD10F2056)

Muhammad Nurazman Bin Mohamed Edin (01DAD10F2062)

LIMITED SLIP DIFFERENTIALS A limited slip differential (LSD) is a type of

automotive differential gear arrangement that allows for some difference in angular velocity of the output shafts, but imposes a mechanical bound on the disparity.

a limited slip differential is used in many vehicles. It is very similar to the standard unit but has some means of preventing 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. Other names for a limited slip

Limited Slip Differential

Construction Of Various Type of Differential Clutch Pack Cone Clutch Torsen

Clutch Pack 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.

Cone Clutch 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.

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.

Torsen

Types Of Torsen There are currently three types of Torsen differentials. The original Torsen T-1 (Type A) uses crossed axis helical

gears to increase internal friction. The Type I can be designed for higher torque bias ratios than the Type II, but typically has higher backlash and the potential for Noise, Vibration, and Harshness (NVH) issues, and requires a precise setup/installation.

The later Torsen T-2 (Type B) uses a parallel gear arrangement to achieve a similar effect. There is also a specialist application of the T-2, known as the T-2R (RaceMaster).

The latest Torsen T-3 (Type C) is a planetary type differential, in that the nominal torque split is not 50:50. The Type C is available as single or twin version; the Torsen twin C differential has front and center differential in the same unit.

Operation of Various Type Of LSD Clutch Pack Cone Clutch Torsen

Clutch Pack 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.

Cone Clutch 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.

Torsen 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.

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