With the development of technology and the wide application of computers, the development of transmission technology in the world tends to use hardened gear reducers.According to statistics, the use of hardened gear reducer gears makes the machine lighter in weight, smaller in volume, continuously improved in quality, and increased in working speed by a level.
According to the hardness of the tooth surface, people usually divide gear transmission into two categories, namely hard tooth surface gear transmission and soft tooth surface gear transmission.The hardness of the gear working surface is greater than 350HB or 38HRC is called a hard tooth surface reducer; the hardness of the gear working surface is less than or equal to 280HB is called a soft tooth surface gear; the gear between the two is called a medium hard gear.The corresponding reducer is called a hard tooth surface reducer or a medium hard tooth surface reducer and a soft tooth surface reducer.
First of all, the soft tooth surface reducer, compared with the hard tooth surface reducer, has always been the best choice for the design of domestic traditional cranes because of its simple structure and relatively low price.However, due to the unreasonable basic parameters and the backward technical level, it will inevitably be replaced by various new reducers, especially not suitable for the use of hoisting reducers as important components.
Secondly, the medium hard tooth surface reducer, the gear of this type of reducer has been quenched by the tooth surface, the hardness of the tooth surface has been improved, and it has strong resistance to pitting corrosion and wear resistance. The strength is greatly improved, so that the life is improved.The representative type is the base type QJ-D reducer for cranes.
The gears of the hard-tooth surface reducer have been treated by carburizing and quenching on the tooth surface, so that the hardness of the tooth surface is greatly improved, and it has strong resistance to pitting corrosion and wear resistance. The medium hard tooth surface reducer has been improved, and the service life has also been greatly improved.Representative types such as cylindrical gear reducer ZDY, ZLY, ZSY and crane base type hard tooth surface reducer QY3D, QY4D, QY34D.
The hardness of the tooth surface of the hard tooth surface reducer is nearly double that of the medium hard tooth surface, and it has the characteristics of "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.Studies have shown that for the gear transmission of the hardened reducer, the bearing capacity of the contact strength of the tooth surface is proportional to the square of the hardness, and the bearing capacity of the bending strength is proportional to the square of the hardness.Therefore, the pitting corrosion resistance of hardened and tempered gears is increased by 2.5-3 times, the bending resistance is increased by 1-1.5 times, and the wear resistance is increased by 0.3 times when the tooth tangent speed is 2.3m/s.