Development outline of reducer gear technology
Almost all modern industrial systems contain reducer gear devices, which even go deep into the daily production of thousands of households. Reducer gear is the key component of mechanical products. The quality of reducer gear is related to the level of the whole product, and reducer gear factory is regarded as the symbol of industry.
According to DWDudley, a famous American reducer gear expert, the development of reducer gear technology in the past 100 years from 1890 to 1990 can be roughly divided into four periods, and each period is characterized by the progress in reducer gear design and reducer gear manufacturing.
During the period from 1890 to 1930
The main progress in the design and manufacture of reducer gear was as follows: the calculation formula of bearing capacity of reducer gear was initially established. Cycloidal and involute reducer gears are used. The basic types of reducer gear transmission are spur gear, oblique reducer gear, conical reducer gear and worm drive reducer gear. Gear hobbing machine, gear shaper and gear grinding machine were invented and widely used. Can process the gear of large reducer and grind it with cast iron grinding tool, so as to achieve higher accuracy.
During the period from 1930 to 1960
The main progress in the design and manufacture of reducer gears was as follows: the formulas for calculating the bearing capacity of straight, helical and cylindrical reducer gears were developed. Start trimming the tooth profile and helix (in order to improve the bearing capacity of the gear). Generally, involute reducer gear with pressure angle of 20 is used, while involute reducer gear with high bearing capacity with pressure angle of 25 is used in spacecraft and aircraft.
Gear shaving machine has been developed, and it has been widely used in finishing after gear cutting (polishing and grinding are rarely used). The gear shaper with gear shaper cutter head was invented and used in rapid gear cutting. The measuring instruments for measuring involute, helix and pitch have made great progress. The anti-gluing extreme pressure additive for reducer gear was developed.
During the period from 1960 to 1980
The main progress in the design and manufacture of reducer gears was as follows: the previous formulas for calculating the bearing capacity of straight and oblique reducer gears were greatly improved. Basically, all the power transmission reducer gears used are designed as involute reducer gears. With the displacement of the center distance, the pressure angle changes in the range of 20 ~ 25. Finishing reducer gears by rolling and grinding has been applied.
The precision of gear cutting and grinding machine tools is higher. For reducer gears with strict requirements, it is necessary to check the cracks caused by the transition curve of the tooth root when cutting teeth or the burns and grinding cracks that occur during grinding. Scraping method has been used to process reducer gears with hard tooth surface, which is much higher than the usual reducer gears.
During the period from 1980 to 1990
The main progress in the design and manufacture of reducer gear is as follows: the thickness of elastic hydrodynamic lubricating oil mold in contact area must be considered in the calculation formula of pitting corrosion of reducer gear, and it should be calculated as an important parameter.
It is clearly recognized that even within the allowable limit, damage such as pitting and wear can lead to gear breakage and failure of reducer (even if the gear is not worn, this will happen when it bears a considerable load). In order to reduce noise, straight or oblique reducer gears with extra-high tooth profile with overlapping coefficient of more than 2 are used.
The metallurgical quality of reducer gear steel has been strictly controlled, and new reducer gear materials have been developed, which have much higher strength and high temperature resistance. The gear of hard tooth surface reducer is finished by scraping method or CBN cutting method, and high-speed grinding is carried out by grinding wheel. The geometric accuracy of reducer gears is mostly detected automatically.
The heat treatment process of steel straight reducer gear is more strictly controlled. To meet more stringent engineering and technical requirements. The gear transmission device of hard tooth surface reducer has been gradually applied in various industries with high transmission power and requirements for vibration and noise.
Since 1990, high-precision hard-tooth-surface reducer gears have been widely used in various fields, especially in large kiln mills and roller mills in cement industry.