The transfer case is a device that distributes engine power and is the core power distribution unit in four-wheel drive vehicles. It is responsible for transmitting the engine's output power to different axles as needed. Its core functions include switching between two-wheel drive and four-wheel drive modes, and amplifying torque through gear ratios in low-speed four-wheel drive mode.
The transfer case is a gear transmission system, mainly consisting of an input shaft, output shaft, differential mechanism, and control module. The input shaft connects to the gearbox, and the output shaft connects to each drive axle. Differential mechanisms, such as a central differential or multi-plate clutch, allow the front and rear wheels to rotate at different speeds. The shifting mechanism achieves mode switching through mechanical or electronic control, and the control module, such as the ECU, can read data such as vehicle speed and speed difference to automatically complete the switching. The front output shaft drive system often uses a low-noise multi-row chain drive, which has advantages such as smooth transmission and low noise.
The transfer case has undergone five generations of development. The fifth-generation transfer case uses die-cast aluminum alloy and a toothed chain drive output. Its low-gear uses a planetary helical gear mechanism, which is lightweight, reliable, has high transmission efficiency, is simple to operate, has a compact structure, and lower noise.
