# Load contact analysis of gear teeth

Gleason system is the main spiral bevel gear produced and used in China. Gleason gear technology has been the object of competitive research at home and abroad for decades because of its good transmission performance, unique meshing theory and processing equipment. The tooth cutting calculation program provided by Gleason company includes tooth contact analysis (TCA program for short). Tooth contact analysis is to simulate and analyze the meshing process of gear pair by computer, which provides better design parameters and basic basis for tooth cutting adjustment parameters for gear design and manufacturing. Many experts and scholars in China have done a lot of research work and achieved extensive results. They have basically clarified the theoretical basis of Gleason technology and played an important role in guiding the design and manufacturing of gears. Because the meshing quality of spiral bevel gear is guaranteed by correct tooth cutting design, but the tooth cutting design is usually carried out for the selected reference point on the tooth surface. The correct design result will provide the desired good Meshing Conditions for spiral bevel gear in the reference point and field. However, whether such meshing quality can be maintained in all meshing processes needs to be further verified by tooth contact analysis.

Previous studies mainly focused on the geometry of gears and the calculation of related cutting parameters. At the same time, because TCA is based on the assumption that the teeth are rigid and there is only one pair of teeth in contact at any time, the analysis results are far from the actual load-bearing running gear pair. TCA is only a pure mathematical method. It does not consider the practical problems such as machine tool error, machining error, installation error and heat treatment deformation. For point contact gears, under light load, the shape of instantaneous contact area of gear teeth is approximately elliptical, and the shape of instantaneous contact area of gear teeth will change with the increase of load. When the tooth edges are in contact, the situation becomes more complex. Therefore, it is necessary to break the rigid hypothesis and single tooth meshing hypothesis in tooth contact analysis, and establish a set of solutions to the real contact area of gear pair under load, transmission error curve, the number of teeth meshing at the same time at a certain moment, the load distribution between pairs of teeth meshing at the same time The calculation method of meshing characteristics such as load sensitivity of gear pair and peak contact stress of tooth surface at a certain instant.

Since M. L. Baxter carried out tooth surface contact analysis, the design and machining of spiral bevel gears have developed greatly. Since then, many gear scholars have developed tooth contact analysis methods. Experts from Gleason company study the loading contact process of gear teeth, put forward a set of loading gear tooth contact analysis method, and developed the corresponding computer software, namely loading gear surface meshing analysis, referred to as LTCA. The research on loaded gear tooth contact analysis has also been carried out in China, and the gear tooth contact analysis method has been improved to make the gear tooth contact analysis closer to the actual working state. However, when carrying out the loaded contact analysis of gear teeth, they ignore the change of load distribution caused by the change of contact area shape, which makes the analysis results have a certain gap with the actual work of gear pair.

With the development of mechanical industry, gear transmission with compact structure, long service life and suitable for heavy load and high-speed working conditions is more and more widely used. There is still a big gap between China’s gear transmission products and the foreign advanced level. Generally speaking, the gears produced by some domestic manufacturers have poor quality, short service life, low bearing capacity and high noise. For example, the gears in automobile, machine tool and other equipment generally fail to meet the national standards; In metallurgical mining machinery, general machinery, automobile and other products, the service life of gears is only 1 / 3-1 / 2 of that of foreign products. Therefore, in order to meet the development of machinery in the direction of high speed, heavy load, low noise and high efficiency, it is of great theoretical significance and application value to carry out gear meshing principle and gear loaded contact analysis (LTCA) considering elastic error.

Now, tooth loaded contact analysis (LTCA) has attracted extensive attention at home and abroad. This technology is a bridge connecting geometric design and mechanical analysis in the field of gear research. It plays a key role in the research of various gears, especially in the design, analysis and manufacturing of spiral bevel gears.

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