The factory maintenance period of GEC39-8 and GMSD60 locomotives in the United States is 800,000 to 1 million km; the repair period of GEC36-7 locomotives in the United States is 1.6 million to 2 million km, and C36-7 is imported in China in the 1980s. The ND5 locomotive has a traction gear life of 1.5 million to 1.6 million km, and the warranty period for each pair of traction gears is 800,000 to 1 million km. It is inferred that the warranty period of the US locomotive traction gear should not be lower than 800,000 to 1 million km.
Common failure modes of locomotive traction gears Before the mid-1980s, the drive gears of traction gears of domestic and electric locomotives suffered more damage, and the proportion was also large. For example, when the DF4 locomotive drive gear was repaired for the first time, the replacement rate was 80, the driven gear replacement rate was 13, and the old DF locomotive drive gear traveled an average of 800,000 km, but the reliability probability was not high, and some gears were less than one factory. Repair period. Although the service life of traction gears of DFH1 diesel locomotives has reached 600,000 km, the spiral bevel gears of new hydraulic transmission diesel locomotives (modulus increased from ms=12mm to 14.5mm) need to be replaced every four repair periods. One of the points. During the period from 1974 to 1980, Baoji Electric Power Division conducted statistics on the active traction gear life of the SS1 locomotive. The shortest life was less than 10,000 km, generally only 151,200 km. With the continuous enrichment and manufacture of practical experience. The improvement of the level, especially the application of the sharp-edged grinding hob in the fine hobbing process, the improvement of the carburizing and quenching process level, the reduction and avoidance of the grinding crack, the quality problem of the driving gear is solved to some extent, such as The service life of the traction gear of the SS1 locomotive has reached 600,000 km, but the reliability probability is still not high. Since then, the quality problem of the driven gear with the intermediate frequency quenching as the final hardening method has gradually been exposed, and has not been solved so far.
As we all know, gears must be used safely, and must have certain bending fatigue strength, contact fatigue strength, scratch resistance, anti-adhesive ability and sufficient wear resistance. The practical application shows that the failure modes of traction main and driven gears of various types of internal combustion and electric locomotives in China mainly include contact fatigue damage characterized by extreme wear, pitting, abrasion and gluing, and characterized by gear tooth damage. Bending fatigue damage, etc.
Although only 10 of the damage of the traction gear of the locomotive in China is due to the extreme wear, the geometrical shape of the tooth shape and the variation of the meshing parameters caused by the tooth wear have an important influence on the reliability and life of the gear transmission. An expert from the former Soviet Union also pointed out that about 30 of the total failures of diesel locomotives are wheelsets - motor sets, and parts and parts of traction motors are often damaged. This is mainly due to the high frequency dynamic loads generated by the interaction of partially worn teeth in the traction gear. Generally, the traction drive gear wears more evenly, and the involute tooth shape does not change much; the driven gear wear is very uneven, and the damage to the involute profile is much more serious. In addition to poor lubrication, other contact fatigue damage can also cause abnormal wear and eventually failure of the gear.
On the problem of pressure angle When the locomotive is moving to heavy load and high speed, it is inevitable to optimize the structure and main parameters of the traction gear. The most important and most sensitive parameter is the modulus and pressure angle. However, the method of simply increasing the gear modulus to increase its load carrying capacity is generally limited. So what are the advantages and disadvantages of increasing the gear pressure angle? In recent years, some experts and scholars have carried out in-depth analysis and research on this issue, which is worthy of reference and reference.
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