Efficiency is a very important performance index for the transmission of power. Low transmission efficiency will not only result in the loss of transmission power, but also because most of the lost power is converted into heat energy, which makes the temperature of the transmission system rise, and easy to cause lubrication failure, thus reducing the service life of the transmission system. The efficiency of gear transmission is directly related to the specific transmission form. The transmission efficiency can be directly improved by adopting the high efficiency gear transmission form. The loss of gear transmission efficiency can be divided into power transmission loss and non power transmission loss according to its main influencing factors.
The loss of power transmission is mainly the friction loss of tooth surface, but the loss of non power transmission mainly includes the loss of wind resistance, the loss of stirring oil and the loss of sealing. At present, the efficiency research of gear transmission mainly focuses on three aspects: new transmission form, power transmission loss and non power transmission loss.
Hohn et al. Used planetary gear mechanism with low efficiency loss to reduce the friction loss of gear pair, which made NGWN planetary gear mechanism meet the requirements of large transmission ratio under the condition of realizing high efficiency. Stahl et al. Studied the transmission efficiency of parallel shaft gear under the condition of grease lubrication, and pointed out that grease lubrication can significantly reduce the no-load loss compared with oil lubrication under the condition of large immersion depth and high speed. Stahl et al. Studied the transmission efficiency of worm under the condition of grease lubrication. Compared with oil lubrication, the efficiency of grease lubrication is higher at low speed. Considering the effects of viscosity and air density of lubricating oil, handschuh et al. And concli et al. Used the methods of hydrodynamic analysis and flow field experiment to quantitatively study the loss of wind resistance, stirring oil and rotating oil seal of high-speed gear. Handschuh et al. Conducted an experimental study on the non power transmission loss of high-speed gear transmission system. Concli et al. Studied the influence of spur gear tooth geometry on wind resistance loss.