The drive application of the gear has actually appeared very early. Now with the development of production, the smooth operation of gear has received more and more attentions.
The gear forging is mainly used in automotive manufacturing, petrochemical engineering, mining machinery and other fields. The main materials are 20CrMnTi, 40Cr, 42CrMo and so on. It is each of the protruding parts on the gear which is used to engage. These protruding parts are generally arranged radially, and the gear wheel on the pair of gears contact each other, which can make the gear continuous engaging operation.
The tooth space of the gear forging is the space between the two adjacent teeth on the gear. The end face is a cylindrical gear or cylindrical worm that is perpendicular to the plane of the gear or worm axis. The end face is the plane at both ends of the gear. The normal plane refers to the plane perpendicular to the tooth trace of the gear wheel.
The development of gear forging technology is shown in the improvement of precision grade and production efficiency. The accuracy of low speed gear is improved from the past 8 ~ 9 grade to 7 ~ 8 grade. The gear of lathe bed is improved from 6 ~ 8 grade to 4 ~ 6 grade. The gear of rolling mill is improved from 7 ~ 8 grade to 5 ~ 6 grade.
For the small and medium size gear with small modulus. The hobbing efficiency is improved greatly due to the development of high performance hobbing machine and the improvement of cutter material. With the multiple thread hob, the cutting speed can reach 90m/s under the condition of roughing feed. If the quenched and tempered steel gear of the right and left of the modulus 3 is machined with the super hard hob, the cutting speed can reach 200 m/s. To improve the efficiency of gear shaping, it is necessary to be limited by the reciprocating motion mechanism of the cutter of gear planer.
In the heat treatment process of gear forgings, generally there are four kinds, namely induction quenching, nitrogenization, carbon infiltration, and tempering. The general trend is to improve the hardness of the tooth surface. The carrying capacity of carbonized and quenching gear is 2 ~ 3 times higher than that of tempered gears. Carbonized and quenching gear can obtain high surface hardness, wear resistance, toughness and impact resistance, and can provide high pitting corrosion resistance and fatigue resistance.