Since the 1980s, Cr-Ni steels such as 20Cr2Ni4A and 18Cr2Ni4WA have been widely used in domestic mining machinery. Strict heat treatment process requires carburized hard-toothed gears to improve gear strength and load-bearing capacity; two high-temperature tempering after carburizing and quenching to eliminate brittleness and internal stress after quenching, so that the core of the tooth has a higher impact Toughness; strict control of carburizing concentration and depth of carburized layer is required. The surface carbon concentration is strictly controlled at 0.75 to 1.0, and the carburized layer depth is controlled at 1.6 to 2.0 mm, that is, (0.15 to 0.20) mn, (mn is the gear surface modulus), and data indicates that the effective hardened layer depth is the value. At the same time, it can satisfy both high contact strength and bending strength. After carburizing and quenching, ice-cooling treatment should be adopted to eliminate residual austenite as much as possible to improve its hardness. Finishing uses scraper gear cutter to improve the fatigue strength of the tooth surface and reduce pitting, spalling and fatigue of the tooth surface. The chance of the tooth.
Sealing structure Because the reducer is often operated under the conditions of coal rock mud water, coal dust, rock powder and other debris, in the past design, the labyrinth seal and the skeleton oil seal are often used. In actual work, coal mud water and other debris are often invaded. Ensure the normal operation of the reducer. Therefore, in this design of the reducer, a large-diameter floating seal is arranged at the eccentric disk of the large bevel gear, and a floating seal is also installed at the output shaft of the small bevel gear. In the 1000h life test, the reducer has no leakage oil phenomenon. In the downhole test, no debris intrudes into the interior. It has been proved that the sealing performance is good and the service life is long, which has achieved the expected effect of the design. From September 1995 to January 1996, the reducer was used in the performance test and durability test of the National Coal Mine Excavation Machinery Quality Inspection and Testing Center according to the coal industry standard MT291.1-92 cantilever type roadheader transmission gear box inspection specification. The performance, temperature rise and efficiency of the reducer all meet the standard requirements. The rated load is continuously operated for 2 hours, the temperature rise is only 13.1 °C, and the transmission efficiency of the full load is 97. The reducer is the same as the mainframe in the Datong Mining Bureau. The Jialiang Mine and the Maji Mine conducted underground industrial tests and successfully completed the industrial test indicators required by the test program.
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