联合收获机与油菜直播机连接导轨式悬挂装置研究

Development of Guide Rail Hitch Device Connecting Combine Harvester and Rapeseed Direct Seeding Machine

针对长江中下游地区联合收获机保有量大、利用率低,拖拉机常规三点悬挂装置纵向尺寸大、结构复杂导致机组转弯半径大、重心不稳等问题,基于模块化设计方法设计了一种用于连接联合收获机与油菜直播机的导轨式悬挂装置。在对常规三点悬挂装置运动学分析基础上,从结构紧凑、重心稳定等方面分析确定了悬挂装置的整体结构及工作原理。基于导轨式悬挂装置与联合收获机和油菜直播机的适配关系,从幅宽、重心以及耕深匹配性对其进行理论分析,确定了悬挂装置作业参数和结构参数。利用ANSYS Workbench仿真软件对悬挂装置进行了自由状态下的模态分析,通过分析机架外部激振频率特点和仿真结果,提出悬挂装置结构改进方案,优化后装置前6阶频率分别为54.09、66.35、83.16、130.01、143.52、174.88 Hz,均不在外部激振频率范围内;对优化后的悬挂装置进行静力学分析,结果表明,悬挂装置在提升最高点和作业状态下的应力分别为50.531、140.56 MPa,小于许用应力156.67 MPa。田间试验结果表明,整机运行稳定,当机具以前进速度3.6 km/h进行田间试验时,其耕深稳定性系数为87.42%,碎土率为84.41%,秸秆埋覆率为76.32%,厢面平整度为22.93 mm,各项试验指标均满足油菜播种质量要求。

Aiming at the issues of large inventory but low utilization of combined harvesters in the mid-lower reaches of the Yangtze River,as well as the problems of the longitudinal dimension of the conventional three-point hitch of tractors being large and the structure being complex,resulting in a large turning radius and unstable center of gravity for the unit,a guide rail hitch device suitable for connecting a combined harvester with a rapeseed direct seeding machine was developed by using a modular design approach.Based on the kinematics analysis of the conventional three-point hitch,the overall structure and working principle of the guide rail hitch device were determined from the aspects of compact structure and stable center of gravity.According to the matching relationship between the guide rail hitch device and the combine harvester and rapeseed direct seeding machine,theoretical analysis was carried out from the matching of width,center of gravity and tillage depth,and the operating parameters and structural parameters of the hitch device were determined.The ANSYS Workbench simulation software was used to carry out the modal analysis of the hitch device in a free state.By analyzing the characteristics of the external excitation frequency of the frame and the simulation results,an improvement plan for the structure of the hitch device was proposed.And the first six frequencies of the optimized device were 54.09 Hz,66.35 Hz,83.16 Hz,130.01 Hz,143.52 Hz and 174.88 Hz,which were not within the range of the external excitation frequency.The static analysis of the optimized hitch device showed that the stress values of the suspension device at the highest lifting point and operating state were 50.531 MPa and 140.56 MPa,respectively,which were less than the allowable stress of 156.67 MPa.The field test results showed that the whole machine ran stably.When the field test was carried out with the forward speed of 3.6 km/h,the stability of the ploughing depth was 87.42%,the soil breaking rate was 84.41%,the straw burying rate was 76.32%,and the flatness of the cage was 22.93 mm.The test results showed that all the test indexes met the quality requirements of rape sowing.The research result can provide an idea for the research of a multi-purpose device.