Functions Of Differential gear Box.
When a four-wheeler (car) takes a turn, the outer wheel turns faster than the inner wheel. Thus, there is relative movement between the inner and outer wheel.
The function of the differential is to permit the relative movement between inner and outer wheels when vehicle negotiates (takes) a turn. The torque transmitted to each rear wheel is equal in this case, although their speed is different.
The differential is made up of a system of gears that connect the propeller shaft and rear axles. It is a part of inner axle housing assembly. The assembly consists of differential, rear axles, wheels, and bearings.
The need of differential gearbox:
When a vehicle travels in a straight line, the two rear wheels turn on the road exactly at the same speed and there is no relative movement between two rear wheels.
But when vehicle takes a turn the outer wheel travels on a longer radius than the inner wheel. The outer wheel turns faster than inner wheel i.e. there is relative movement between two rear wheels. If two rear wheels are rigidly fixed to a rear axle, the inner wheel will slip, which will cause rapid tire wear, steering difficulties and poor road holding. Therefore there must be some device, which will divide the input torque of the transmission system between two rear axles. Differential serves this purpose.
Differential gearbox Location :
Location in a different type of vehicle layouts-
1. In Front-engine front-wheel-drive layout – differential is located at the front next to gearbox.
2. In Rear engine rear-wheel-drive layout – differential is located at the rear next to gearbox.
3. Four wheels drive layout – differential is located at the front as well as rear.
4. Front engine rear-wheel-drive layout – it is located at the rear in between two half shafts.
Principle of differential-
If a vehicle travels in a straight line, the two rear wheels turn exactly at the same speed, and there is no relative movement between them. But when the vehicle takes a turn the outer wheel travels a longer radius than the inner wheel i.e. there is relative movement between the two rear wheels. The outer wheel turns faster and covers a larger distance than the inner wheel. The inner wheel makes a larger angle than the outer wheel. thus the vehicle negotiates the turn safely.
Differential gearbox Diagram
Construction of differential:
Major Components of Differential
l. Drive pinion or Bevel pinion
2. Ring gear or Crown wheel
3. Differential case
4. Differential side gear or Sun gears
5. Differential pinions (or) Planet gears
6. Axle shafts or Half shafts
7. Pinion shaft or Cross pin (or) spider.
On the inner ends of each axle a smaller bevel gear called differential side gear is mounted. Two bevel gears are put together to mesh both driving and driven shafts at an angle of 90°. The differential case is mounted with two-wheel axles and differential side gears. The differential case has bearings that rotate two axle shafts. Then, the two pinion gears and their supporting shaft, called pinion shafts, are fitted into the differential case. Then, the pinion shaft meshes with the two differential side gears connected to the inner ends of the axle shafts.
Working of differential gearbox :
TYPES OF DIFFERENTIAL
There are three types of differential :
(a) Conventional type,
(b) Non-slip or self-locking type, and
(c) Double reduction type.
1) Conventional Type
2) Non-slip or Self Locking Type
3) Double Reduction Type
Actual Practical Differential Gearbox Working Video :
Differential Gearbox Animation Video :
Advantages of Differential Gearbox :
2) Both driving wheels can rotate in the same direction at different speeds.
3) Both driving wheels can rotate in the opposite direction at the same speed.
4) Both driving wheels can rotate in the opposite direction at a different speed
Some Questions related to Differential Gearbox
1. What is the function of differential gears?
The function of differential gears:
1. To transmit the torque at the right angle in equal proportion when the vehicle moves straight ahead.
2. To differentiate the speed of road wheels while taking a turn.
3. Equal distribution of torque in all running situations.
2. What is a differential lock?
If one of the rear wheels lying on soft mud or loose dirt and sand, while the other is on the solid ground. At that
time, the wheel which is on soft mud are having less resistance. The wheel lying on soft ground spins or rotates around
its own axis due to differential action, while the wheel on the solid ground is not driven and remains stationary. When
the differential locking is applied, the differential action is stopped and the whole torque is then applied to the
wheel which is gripping on the road.
3. State function of differential.
The function of differential:
1. To transmit the power from the propeller shaft at the right angle to the axle shafts for moving the wheel.
2. To differentiate the speed of two rear wheels when the vehicle makes a turn, i.e. the outer wheel has to travel more distance than the inner wheel or the outer wheel has to run faster than the inner wheel.
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