再深点灬舒服灬受不了了视频_被男同桌扯乳罩捏胸玩乳漫画_双腿张开被5个男人调教电影_爽?好舒服?快?深点av

Development of metallurgical machinery gear theory and manufacturing processes will be further study the mechanism of tooth damage, which is to establish a reliable method of strength calculation basis is to improve the carrying capacity of gears, gear extended theoretical basis of life; the development of a circular arc tooth profile the new tooth representatives; study new materials and manufacturing gear gear new technology; the elastic deformation of gear research, manufacture and installation errors, and the distribution of temperature field, performed tooth modification to improve the smoothness of running gear and at full load increases the contact area between the teeth, thereby enhancing the carrying capacity of gears.

Friction, lubrication technology lubrication theory and metallurgical machinery gears basic research work on the elastic hydrodynamic lubrication theory, promote the use of synthetic lubricants and extreme pressure additives added as appropriate in oil, not only can increase the carrying capacity of the tooth surface but also can improve the transmission efficiency.