The patent is valid for 20 years, which is stipulated by the patent office. It is unified. Aisin's 6AT patent registered in China has a technical protection period of 20 years. Special technology should be used, not just a few sets of gears, so even outdated technology, because there is no technical accumulation, depends entirely on imitation, it is difficult to improve the quality with the support of effective theory.
Basic working principle of automobile gearbox;
Manual gearbox is mainly composed of gears and shafts, which produce variable speed and torque through different gear combinations; Automatic gearbox AT is composed of hydraulic torque converter, planetary gear and hydraulic control system, which realizes variable speed and torque by means of hydraulic transmission and gear combination.
The internal control mechanism of automatic transmission is very precise and the fit clearance is small, so most manufacturers suggest that the oil change cycle of automatic transmission is generally two years or 40 thousand to 60 thousand kilometers. In normal use, the working temperature of gearbox oil is generally around 120 degrees Celsius, so the oil quality is very high and must be kept clean.