Automobile Differential And Final Drive

 Automobile Differential And Final Drive

Differential Application 

The differential is a gear assembly between two shafts that permit the shafts to turns at different speeds while continuing to transmit torque. It is used in drive axles to allow different rates of wheel rotation on curves or corners.

 In other words, the differential of an automobile is a mechanical gearset assembly that provides different speeds and torque to the same axle shaft to the wheels. This mechanism provides both wheels to turn independently when the vehicle taking a turn.

How does differential function? 

When a vehicle travels around a turn, the distance travelled by the outer rear wheels rotates faster than the inner one during a turn. If wheels are mounted on dead axles, there will be the tendency of the wheel skidding, some mechanism must be installed in the rear axle which should reduce speed In the inner wheel and increase the speed of the outer wheel while taking turns. On the other side, it should maintain a constant speed of rear wheels when the vehicle I moving straight. The device that serves this purpose is known as a differential.

 

What will happen if different is not used?

 If different is not used, the vehicle cannot be controlled during a turn, the wheel will skid and tyres may wear out very quickly.

 Differential mainly three types they are-

 Open differential, locking differential and limited-slip differential (LSD). Open differential mechanism commonly used differential on-road vehicles like car to bus. These open differential to achieve different speeds at wheels of the same axle shaft. Open differential one rear wheel is on the surface with good traction and another wheel on less traction or slippery track so that torque flow through the slippery wheel so the vehicles not able more move to overcome this issues, Limited slip differentials are introduced.

Another is the Locked differential used for off-road vehicles and four-wheel-drive vehicles, to provide increase traction and more torque compared to the normally open type of differential vehicle.

In Indian vehicles locked different prefers on off-road vehicles like marinara Thar model, Scorpio, Tata Safari, and military vehicles, etc. Mahindra Thar gave the name Manual locked Differential (MLD). These differential used on offroad conditions. when vehicles get a pothole or uncertain road condition which wheel lose its traction such conditions so differential-locked automatically and laterally provide different speed to the wheel so that help out easily remove from the wheel on such off roads condition. 

A limited-slip differential is very similar to the open differential unit but has an additional component addon differential case like washer and spline clutch disc with a planetary set of gear ( sun gear and star gear set). As it results that prevent wheel spin and loss of torque to the wheel with maximum traction. It works independent motion on the left and axle shaft. It is mainly used offroad vehicles like Ford Endeavour, Toyota Fortuner, Tata new Safari etc.

Final Drive 

In the drivetrain, the final drive is the final or last set of gears before the axle shaft and wheels. When the engine power flow and torque flow through the transmission system via the driveline at the right angle from the propeller shaft to the rear axle and provide a mechanical advantage to the rear axle or front axles. 

The split amount of torque going to each wheel and provides final gear reduction.

In the modern differential, the type of gearing used for the drive pinion and ring ( crown ) wheel is the hypoid gear arrangement.

Differential Troubleshooting 

Noisy differential 

• Less lubricating oil In the differential housing.
• Low viscosity oil or use of poor quality oil.
• Wrong adjustment of the ring(crown) wheel and pinion teeth.
• Worn out hub bearing and worn out bearing ring wheel or pinion.
• Worn out or broken teeth of ring wheel or pinion.
• Less backlash of ring wheel and pinion teeth.
• Broken or worn out thrust washer of star pinion or sun pinion. Loose bevel pinion setup.