Everyone probably had to see footage as a car, literally on the roof covered with mud, storms off-road. Dirt, water, stones - everything flies away from under the car, but it stubbornly moves forward. Of course, not every car is capable of this. The ability to overcome the terrain is laid in the design of the car, turning it into an all-terrain vehicle. One of these features is the differential lock.
What kind of thing is this? In general, there is nothing wrong with her. When the car is moving straight, all wheels have the same speed. But as soon as the car enters a turn, their speed becomes different. The fact is that the wheel passes a smaller path along the inner radius than the outer radius.
So it turns out that wheels located on the same axis must move at different speeds. And this allows you to perform such a device as a differential. Without going into its design features, it should be noted that the differential transmits torque to the wheels from the engine and at the same time allows them to spin at different speeds. However, the existing differentials have one feature - the moment goes where the load is less. If the wheels located on the common axis are in the same grip on the road, then the moment transmitted from the engine between them is distributed evenly.
But if one wheel is located on a slippery section and starts to slip, then the whole moment will be transmitted to it. And the car simply will not be able to move, since the remaining wheels that are in traction with the normal road surface will not receive torque. To avoid such a situation, and differential lock is provided.
Its essence lies in the fact that the moment developed by the engine is distributed evenly on all wheels located on the same axis. There are various options for implementing such a technical solution. There is a manual option when the differential lock is turned on by hand using a special lever. There is an option for automatic locking, it turns on itself when the wheel starts to slip. But the essence does not change - when you turn on the differential lock allows you to ensure the supply of torque to all wheels and overcome the obstacle.
This is especially in demand when driving on the road. Most often, such locks are put on SUVs and all-terrain vehicles. You can even say that the presence of a lock is a necessary requirement for the car to be recognized as an all-terrain vehicle.
However, there is another type of lock that a real cross-country vehicle should have. This is the so-called center differential lock . The fact is that on off-road vehicles, four-wheel drive is most often used , that is, it has power from the engine supplied to all wheels. Usually, a transfer case is used for this, thanks to which the torque is distributed between the rear axle and the front.
But four-wheel drive alone is not a salvation. Here the same situation is possible that occurs when the wheel is slipping. If a wheel starts to slip, the whole moment is transmitted to it. When the front wheel stalls, the rear wheels will no longer be able to help overcome the obstacle. Then, the center lock helps. When it is turned on, the moment is forcibly distributed evenly between the axles, when the rear wheels slip, the front wheels will help to overcome the obstacle, and vice versa.
Differential lock is a mandatory requirement for a cross-country vehicle and allows you to overcome obstacles and bumps on the road. In the absence of any type of blockage, overcoming off-road becomes almost impossible.