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

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