Working principle of the differential
Auto differential can make left and right ( Or front and back) The drive wheels at different speed of rotation mechanism. Mainly by around half shaft gear, two planetary gear and gear rack. Function is when the car turning, or when driving on rough road surface, the left and right wheels at different speed rolling, guarantee on both sides of the drive wheels are pure rolling motion. Differential is to adjust the left and right wheel speed difference and device. In 4 wheel drive, in order to drive the four wheels, must connect all of the wheels, if the mechanical connection together, the four wheels the car is moving in a curve can't rotate at the same speed, in order to let the cars drive curve basic consistency rotation speed, then need to join the middle differential is used to adjust the speed difference of the front and back. Principle of differential this adjustment is automatic, here comes to 'the principle of minimum energy consumption', which is on the earth all objects tend to consume the smallest state. For example, put a grain of beans in a bowl, beans will automatically stop and never stay in the bowl wall in the bottom of a bowl, because the bottom of the bowl is the location of the lowest energy ( Potential energy) , it automatically select stationary ( The kinetic energy minimum) Without constant motion. In the same way, when the wheels turn will automatically to the lowest energy consumption status, automatically adjust the left and right wheel speed according to the turning radius. When turning, because the outside wheel has to pull the phenomenon, the inside of the wheel has the phenomenon of slippage, two driving wheels can produce at this time in the opposite direction from the two additional force, because 'the principle of minimum energy consumption', inevitably leads to both sides of the wheel speed is different, so as to destroy the balance of the three relations, and by reflecting on the axle shaft gear axle shaft, forcing the planetary gear rotation, make the inside of the half shaft speed slow, the lateral half shaft speed is accelerated, so as to realize the difference of on both sides of the wheel speed. If the drive wheels on both sides of the drive axle with a whole rigid connection shaft, the two rounds of only rotating at the same Angle. So, when the car was going to, because the inner wheel than outer wheels move through distance is large, will make the outside wheel pull in of rolling at the same time, and the inside of the wheel slip while rolling. Even the car driving straight, also on the road is rough or although road flat tire rolling radius range ( Manufacturing error, tyre wear different range, uneven load or pressure) Caused by the wheel slip. Wheel slip when not only exacerbate tire wear, increase the power and fuel consumption, still can make difficulty automotive steering, and brake performance becomes poor. In order to make the wheels as far as possible without sliding, in structure must ensure that the wheels can rotate at different angles. Axial: usually driven wheel with bearing on the spindle, can make it in any Angle of rotation, the drive wheels, respectively, with two half shaft, rigid connection between the two and a half shaft is equipped with differential. This differential is known as axial differential. Multiple spindle drive off-road vehicle, to make the drive axle can spin in different angular velocity, driving wheel slip, to eliminate all the bridge equipped with axial differential between the two drive axle. Role, when the car turning inside of the wheel and the outer wheel turning radius, the outer wheel turning radius than the inner wheel turning radius, so when you turn in the lateral of the wheel speed is higher than that of the inside of the wheel speed. The role of the differential is meet the requirements on both sides of the wheel when the car turning speed! This role is the most basic differential role, as to what for development after the central differential, limited slip differential, LSD differential, differential, etc, they are in order to improve the car driving performance and handling performance. Function of the wheel when the car at the corner of the rail line is circular, if the car turn left, the center of the arc on the left side, at the same time, the right side of the wheels go curve is longer than the left wheel, in order to balance the differences, to the left wheel slowly, on the right side of the wheel a little faster, with different speed to compensate for the distance difference. If the shaft into a whole, can't do it on both sides of the wheel speed difference, namely do not automatically adjust. In order to solve this problem, as early as one hundred years ago, the French Renault founder Louis Renault is designed the differential this thing.