挖掘机行走马达正反向输出扭矩一致性技术研究

Research on the Consistency of the Positive and Negative Output Torque of the Excavator Travel Motor

针对某型号挖掘机液压行走马达正反向输出扭矩不一致问题展开研究,分析得出马达正反向输出扭矩不一致的主要原因为马达正反向进出口压差偏差大,而导致压差偏差大的主要因素为马达正反向回油平衡阀阀口尺寸公差的不一致性。建立马达平衡阀阀口尺寸链模型,分析平衡阀阀芯、弹簧座、平衡阀阀头及端盖割槽尺寸公差对平衡阀阀口尺寸公差的影响。通过CFD仿真及阀口各组成环尺寸链优化设计,结合零部件实际加工难度进行公差分配,使马达回油平衡阀阀口尺寸保持在0.5~0.7 mm,从而缩小马达背压变化范围。试验结果表明:优化后的马达平衡阀口尺寸公差使马达进出口压差保持一致,从而保证了马达正反向输出扭矩的一致性。

The problem of inconsistent positive and negative output torque of hydraulic travel motor of an excavator was studied,the main reason for the inconsistency of the positive and negative output torque of the motor was the large differential pressure between inlet and outlet,and the main factor leading to large pressure difference deviation of the positive and negative of the motor was the dimensional tolerance of the valve port in balance valve was inconsistent.The dimension chain model of motor balance valve port was established,the influence factors about dimension tolerance of the balance valve port,such as valve core,spring seat,valve head and end cover groove,were analyzed.With CFD simulation and optimization design of the each valve port dimension chain,combined with the actual processing difficulty of parts,the tolerance distribution was carried out,so the valve port size of the motor oil return balance valve was kept at 0.5~0.7 mm,and then the variation range of motor back pressure was reduced.The test results show that the optimized dimension tolerance of motor balance valve keeps the consistency of the differential pressure between the inlet and outlet,thus the consistency of the positive and negative output torque of the motor is ensured.