  |
All of us have at some point seen an I.X. immobilized in the sand in summer, next to some beach, with its two driving wheels spinning "crazily", but without being able to move the car. It is perhaps the simplest and most typical example that shows the limits of two-wheel drive systems and at the same time explains why all off-road cars have some form of four-wheel drive.. That is, a four-wheel drive system. Wheel spin is a phenomenon that occurs much more easily on dirt, in the mud, in the sand, in the snow etc. and can drive, under certain conditions, at a complete stop of the car. You see, when we have "crazy" spin of one wheel, the other is immobilized and (due to the basic operation of the differential) it cannot transfer force to the ground and "unstick" the car.
When the drive is transmitted to all wheels, the force each tire must "put" on the road to move the car is halved and, consequently, traction is clearly more difficult to lose. This means that the ability to move on surfaces with a low coefficient of friction is increased, such as soil and mud. We recall that the spin begins when the force exerted by the wheel on the road (to push the car) exceed the limit determined by the quality of the soil. To transfer the drive to all four wheels, some additional components are required to be added to the transmission system. This is an intermediate transfer case (transfer case), which may include a differential, or some type of clutch that is responsible for dividing the drive between the two axles (back and forth). The type of four-wheel drive one wants to achieve also determines the type of components that will be added.
Click –> Τύποι συστημάτων μετάδοσης της κίνησης στους τέσσερις τροχούς