Combined reducers for rolling stands
Background. The final stage of smelting is the production of long products. The technological process was developing from individual rolling 100-kg ingots to continuous rolling 2-ton ingots. The arrangement scheme and the drive of working stands of section mills were one-stand, sequential, linear, sequentially-continuous and continuous. Currently, long products production is carried out on continuous rolling mills. The main design decision in the drive of rolling mill stands is the use of combined reducers. These reducers combine the functions of changing rotation frequency, torque and split torque (reducer and gear stand). Determination of the development tendencies of combined reducers’ designs will allow making informed decisions when designing new and reconstructing operating drives. The analysis of characteristic failures is necessary for the further improvement of the reducers’ reliability. Materials and/or methods. The study is based on a review of the development of combined reducers of various design solutions. Various types of combined reducers for rolling stands of section rolling mills and the main causes of fault in the specific design solution are examined. Results. The design solution, while remaining fundamentally unchanged, has been used in designing the drives for the working stands of section mills for a long time. The main differences are associated with the hull elements, their location, the assembly sequence, unchanged remains the high rigidity hull combined with rigid shaft installing in roller bearings. There is a lack of reliability of lubrication systems represented by spray nozzles; the rate of damage development, in this case, is large and can not be prevented by carrying out regular inspections. The review indicates a waiver of the vertical location of the motors and installing them in a horizontal position, notwithstanding the use of a more complicated in design and maintenance conical-cylindrical reducer. Conclusion. The analysis of the structure development of combined reducers shows that the main differences are associated with the hull design, the most typical failures are caused by a disturbance in the lubrication regime, and the optimal design solution involves a horizontal location of the electric motors of combined reducers.