O’zbekistоn respublikasi оliy va o’rta maxsus ta`lim vazirligi

18.6 Operating methods
Even the most perfect friction pair in design will quickly fail if it is not properly maintained. When operating steam, certain rules must be followed to reduce wear. The set of operational methods for increasing the wear resistance of friction pairs includes the following.
Run-in - testing of machines before putting them into operation. The purpose of the running-in is to run in a single complex all friction pairs included in the machine, creating an optimal roughness in them. Lubrication of friction pairs gives the greatest effect when the following recommendations are followed:

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  The lubricant ages during the operation of the friction unit, i.e. its operational properties change as a result of tribochemical processes, primarily oxidation, thermal degradation, clogging with wear products. Therefore, it is advisable to monitor the condition of the oil in the lubrication system and replace it with fresh oil.
  
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  The most important requirement for this operation is the purity of the oils. Care must be taken during transport, storage and refueling to prevent contamination of the oil. Before replacement, the lubrication system is flushed with a special flushing oil. When replacing, use only the oils specified in the instruction manual for the friction pair. The terms of replacement depend on the operating conditions of the pair and are assigned based on operating experience.
  

Starting the machine is a crucial moment in its operation. During breakaway and in the initial period of operation of friction pairs, the boundary mode of friction or friction without lubrication predominates. Therefore, when starting the machine, the load is increased gradually and smoothly. Increased wear of the chassis of transport vehicles occurs during braking and stopping.
Repair , i.e. correction of damage, repair of a friction pair is carried out when the wear limit is reached. It corresponds to: a sharp increase in the intensity of wear, the maximum allowable decrease in the strength of the wear part, the unacceptable effect of wear on the performance of other parts. Service life of friction pairs serve as the basis for repair planning. Such data are available for many mass- produced machines.