How is the transfer case arranged?

The dispenser (or dispenser) is an integral part of every four-wheel-drive vehicle. Its function is to distribute the torque (hereinafter CM) along the axes of the machine, as well as in its increase when traveling off-road or bad roads.

The transfer case has the following device:

- the drive shaft transmits the torque (hereinafter CM) from the gearbox to the dispensing box;

- the axle differential is needed to distribute the CM between two axes;

- The mechanism that blocks the differential between the axles provides a stronger connection between the rear and front axles. The lock is done manually or automatically;

- transmission of chain (or tooth), drive shafts of the rear and front axle, transmission reducing.

For a more complete realization of the capabilities of the all-wheel-drive machine, a mechanism is used that blocks the differential between the axle, that is, its partial or complete shutdown. Modern mechanisms of automatic interlocking of the interaxle differential are a friction clutch of multiple discs, a differential self-locking and viscous coupling.

Viskomufta (another name - viscous coupling) is the most inexpensive and simple device. Its work is based on the appearance of a blocking element with a certain difference in the velocities of the axes. The dispenser is most often equipped with viscous.

The self-locking differential is a special design, which consists of worm gears - driven and driven. Locking becomes possible due to friction in the worm gear. Since such a differential has limitations in strength, it is not used on off-road vehicles.

The friction multi-plate clutch distributes the CM between the axes, depending on the external conditions. In this case, the CM is redistributed on the axis, which has better grip on the road. To ensure the operation of such a clutch, the transfer case can be equipped with a hydraulic or electric drive, as well as an electrical control system.

Locking forced (or manual) is possible only with the help of the driver. In this case, a hydraulic, electric or mechanical drive is used.

The chain transfer function is to transfer the CM to the front axle of the machine. It includes the driven and driving wheels of the gear, as well as the drive chain. Instead of a chain, the transfer case can be equipped with a spur gear. On modern machines, the downshift looks like a planetary gearbox.

On some cars with a 4x4 system, it is possible to connect the front drive manually (for example, UAZ transfer case). Some designs have a permanent drive system with the option of switching off the front axle.

The dispenser can operate in several modes: the rear axle is turned on; Both bridge machines are included; Both bridges work when the differential of the interaxle is blocked ; Both bridges operate on the lowering gear when the differential is locked; Both axles work with the differential lock.

Switching modes is via the lever, rotary switch or buttons on the panel.