With the development of technology and the wide application of computers, the development of the world's transmission technology tends to adopt the hardened gear reducer. According to statistics, the adoption of hardened gear reducer gears makes machines lighter in weight and smaller in size, with ever-increasing quality and an increase in working speed by one grade.
According to the size of the hardness of the tooth surface, usually people will gear transmission is divided into two categories, namely, the hard gear surface gear transmission and soft gear surface gear transmission, there are also divided into three categories, that is, to increase a class of medium-hard gear transmission. The hardness of the working surface of the gear is greater than 350HB or 38HRC is called hardened gear reducer; the hardness of the working surface of the gear is less than or equal to 280HB is called soft gear; in between is called medium-hard gear. The corresponding reducer is called hardened gear reducer or medium hardened gear reducer, soft gear reducer.
First of all, soft gear reducer, compared with hard gear reducer this type of reducer due to the simple structure, relatively inexpensive, has been the optimal choice for the design of domestic traditional cranes. However, due to the basic parameters are not very reasonable, backward technology level, will inevitably be replaced by a variety of new reducer, especially not suitable for use as an important part of the hoisting reducer.
Secondly, in the hardened gear reducer, such reducer gears after tooth quenching treatment, the period of tooth hardness increased, with strong resistance to pitting and wear resistance, the heart has a better toughness, so that the tooth root strength is greatly improved, so that the life has been improved. Representative types such as cranes with base QJ-D reducer.
The gears of hardened gear reducer are treated with carburizing and quenching on the tooth surface, so that the hardness of the tooth surface is greatly improved, with strong resistance to pitting and abrasion, and the heart has good toughness, so that the strength of the tooth root is improved than that of the medium hardened gear reducer, and the service life is greatly improved. Representative types such as cylindrical gear reducer ZDY, ZLY, ZSY and crane base type hardened gear reducer QY3D, QY4D, QY34D.
The tooth hardness of hardened gearheads is nearly double that of medium hardened gearheads, and it is characterized by "hardness on the outside and toughness on the inside". Because the bearing capacity of the tooth surface is related to the hardness of the tooth surface, the higher the hardness, the higher the bearing capacity. Some studies have shown that, for hardened gear reducer gear transmission, tooth contact strength of the bearing capacity and hardness of the square is proportional to the bending strength of the bearing capacity and hardness of a square is proportional to. So the hardened gear than tempered gear pitting resistance increased by 2.5-3 times, bending resistance increased by 1-1.5 times, anti-wear capacity in the tooth tangent speed 0.3m/s when increased by 2.3 times.