Balancing is a process that improves the mass distribution of the rotor to ensure that the vibration or vibration force caused by imbalance during rotation of the rotor in its bearings is reduced to a permissible range.The rotor imbalance can be reduced to a fairly small range by using existing measuring instruments, but it is not economical and unnecessary to require too much balance quality.
Therefore, it is necessary to determine to what extent the imbalance should be reduced in order to resolve the relationship between technical possibilities and economic rationality.Eccentric distance in gear drive system can be determined according to GB/T9239-1988.The balance quality required for a rotor is usually determined by empirical method, which is based on the balance level established.A balanced quality level includes an allowable imbalance range from the upper limit to zero, a balanced quality level upper limit G, in mm/s.
According to the regulations of JB/ZQ4165-1997, G16 and G6.3 are recommended for balance quality of heavy duty machinery industry.The dynamic characteristics of gear drive system in three different dynamic balancing accuracy classes are compared and analyzed. In addition to the above two accuracy classes G6.3 and G16, a higher dynamic balancing accuracy class G2.5 is also introduced.Taking 7th gear as an example, the maximum dynamic engagement force of gear pair and bearing support reaction force under different dynamic balance accuracy are shown in the figure.
It can be seen from the diagram that under the three kinds of dynamic balancing accuracy, the maximum dynamic meshing force of each gear pair in gear 1-8 does not change significantly, which indicates that improving the dynamic balancing accuracy does not reduce the dynamic load.Further analysis is made on the scatter plots of dimensionless vibration displacement amplitudes of each concentrated mass point under different dynamic balancing accuracy as shown in the figure.It can be seen from the diagram that the dimensionless vibration displacement of each concentrated mass point has no obvious change trend with the improvement of dynamic balance accuracy.The above analysis shows that the dynamic balance accuracy grade G16 can satisfy the requirements of dynamic performance for the gear drive system of tracked vehicle studied in this paper.