Abstract: The digging performance of the main digging area was a key indicator in the analysis and evaluation of digging machine performance， and the scope definition directly affected the evaluation results， while the operating force arm was inseparable from the operating range and digging force performance. Taking a 22 t backhoe hydraulic excavator as an example， the concept of force arm coefficient was introduced and based on the force arm curve and the transmission ratio curve of each mechanism， different main digging force arm coefficients were selected and the force arm variations caused by different digging methods were used as the basis to establish the main digging force arm proportioning scheme. Based on the work domain mapping analysis method and the limit digging force model， the theoretical digging force and the limiting factors were solved to analyze the digging performance of different main digging areas separately. The results show that for the working ranges， the bucket force arm mainly affects the digging height and discharge height， the bucket bar force arm mainly affects the digging diameter and the moving arm force arm mainly affects the digging depth and digging height. For digging performance， increasing the force arm of an operating cylinder may increase the digging force， while the corresponding operating cylinder full play ratio may decrease； on the contrary， increasing the force arm of a non-operating cylinder may have less effect on the digging force， but the operating cylinder full play ratio may increase； the bucket rod force arm mainly affects its average digging force， while the bucket force arm mainly affects its maximum digging force. Then， the main digging area formed by the 0.6∶0.8∶0.6 force arm coefficient ratio for bucket rod digging and the 0.6∶0.8∶0.8 force arm coefficient ratio for bucket and compound digging is taken as the best digging performance main digging area for their respective digging methods. The paper proposes a method of defining the main digging zone by the ratio of the main digging force arm coefficient， revealing the influences of different main digging force arm ratios on the digging performance， providing evaluation indicators and reference directions for digging performance analysis and working device optimization. 

Key words: hydraulic excavator, main digging force arm ratio, optimal main digging area, digging performance, work domain mapping analysis method

摘要： 主挖区的挖掘性能是分析评价挖掘机性能的关键指标，其范围界定直接影响评价结果，而作业力臂又与作业范围和挖掘力性能密不可分。以某22 t反铲液压挖掘机为例，引入力臂系数的概念并基于力臂曲线和各机构传动比曲线，选取不同主挖力臂系数并以不同挖掘方式所引起的力臂变化为依据建立了主挖力臂配比方案。基于工作域图谱分析法和极限挖掘力模型，分别求解其理论挖掘力和限制因素来分析不同主挖区的挖掘性能。研究结果表明：对于作业范围，铲斗力臂主要影响其挖高和卸高，斗杆力臂主要影响其挖径，动臂力臂主要影响挖深和挖高。对于挖掘性能，增大某作业缸力臂会使得挖掘力增大，而相应的作业缸充分发挥比会减小；相反，增大某非作业缸力臂对挖掘力影响较小，但其作业缸充分发挥比会增大；斗杆力臂主要影响其平均挖掘力，而铲斗力臂主要影响其最大挖掘力。基于此，将对于斗杆挖掘以0.6∶0.8∶0.6的力臂系数配比、对于铲斗和复合挖掘以0.6∶0.8∶0.8的力臂系数配比方案所形成的主挖区作为各自挖掘方式的最佳挖掘性能主挖区。该研究提出了以主挖力臂系数的配比方式定义主挖区的方法，揭示了不同主挖力臂配比对挖掘性能的影响规律，为挖掘性能分析和工装优化提供了评判指标和参考方向。

关键词: 液压挖掘机, 主挖力臂配比, 最佳主挖区, 挖掘性能, 工作域图谱分析法