With the rapid development of planetary transmission technology, with the small size, light weight, compact structure, large bearing capacity, high transmission efficiency, stable operation, strong impact resistance and large transmission ratio of the planetary reducer, the synthesis and decomposition of motion can be realized. and many other advantages.Planetary reducers are widely used in various industries.
Especially it plays an important role in coal mine safety production. Various large-scale equipment such as conveyors and loaders need and frequently use planetary reducers. Therefore, improving the carrying capacity and increasing the service life of planetary reducers has become an important topic of discussion. .In planetary transmission, the weak link is often the transmission of gears. In order to improve the bearing capacity of the reducer, it is necessary to improve the performance of involute cylindrical gears under heavy loads to meet the needs of heavy loads.In heavy-duty gear transmission, the internal and external meshing gear pairs must meet the requirements for strength, life and meshing quality, and ordinary designs can no longer meet the requirements for use.
To keep the outer diameter of the reducer unchanged, it is necessary to increase the load-carrying capacity, which can be satisfied by increasing the gear module reasonably and reducing the number of gear teeth.The large modulus gear can improve the bending strength of the gear, and the bending strength is an important indicator of the bearing capacity of the gear.At the same time, the meshing angle a' can also be increased. The increase of the meshing angle is beneficial to increase the comprehensive radius of curvature, reduce the Hertzian stress, and play a role in improving the bearing capacity.
In order to improve the bearing capacity of the gear, it is necessary to analyze the failure cause and damage mode of the gear transmission, find out the main contradiction, and then determine the basic principle of selecting the variation coefficient.Planetary reducers generally use hard tooth surfaces (HB7m/s), use oil bath lubrication (2.5m/s 15m/s) at medium speeds, and use forced lubrication at high speeds.In order for the gears to maintain high-efficiency power transmission, a stable oil film must be formed on the meshing tooth surfaces to prevent metal contact.In order to achieve this purpose, it is necessary to select the grease with the appropriate viscosity.A high viscosity index means that the viscosity of the oil changes less with temperature changes, which is conducive to maintaining a small viscosity change within the working temperature range, thereby improving the lubricating performance.In actual selection, lubricating grease is selected according to load and speed, and factors such as transmission power, meshing efficiency, bearing efficiency, and temperature difference between inlet and outlet are also considered.Reducing the roughness of the tooth surface is beneficial to lubrication, and it is easy to form a full oil film.An explanation is given for the point-line contact problem of involute gear meshing.Calculate the thickness and strength of the oil film theoretically, and then choose the appropriate lubricating grease.The value of the amount of lubricating grease loaded, too little lubricating grease will not achieve the purpose of lubrication, on the contrary, in a sealed gearbox, too much lubricating grease will cause excessive stirring loss.
For heavy-duty gears, the working characteristics should be considered in terms of material selection, and the surface is required to reach a certain hardness to ensure contact strength, metal wear resistance, and the core has a certain toughness.To meet these requirements, only carburized and quenched gears are most suitable.For heavy-duty gears, the material is generally made of alloy steel with a carbon content of less than 0.2%, and the alloying elements are generally Cr, Ni, Mo, Ti, etc.These elements have significant effects on improving hardenability, refining grains, improving wear resistance and toughness respectively.When designing, it is necessary to comprehensively consider factors such as strength and technology.The several methods outlined above to improve the bearing capacity and service life of the planetary reducer, production practice shows that they are all effective and can be used as a general design reference.
