Shang Jiajie, Liu Dongmei, Song Xingtao, Han Yibin, He Sitong, Zhang Ying, Liu Liyi, Chen Haitao
Northeast Agricultural University, College of Engineering, Harbin, Heilongjiang, 150030, PR China.
College of Mechanical and Electronic Engineering, East University of Heilongjiang, Harbin, Heilongjiang, 150066, PR China.
Heliyon. 2024 Aug 22;10(19):e36721. doi: 10.1016/j.heliyon.2024.e36721. eCollection 2024 Oct 15.
The sowing depth stability and consistency of the no-tillage planter, particularly the high-speed operation, are poor. A reason for this is that the structure and parameter selection of no-tillage planter row unit profiling mechanism are unreasonable. The stability and consistency of sowing depth is beneficial when the upper and lower links of the parallel 4-bar profiling mechanism (PFPM) are parallel to the ground, but this principle is not satisfied on the uneven no-till soil. To improve the stability of gauge wheels downforce (GWD) and sowing depth of no-tillage planter row unit. The variation law of spring additional downforce (SAD) with tilt angle of parallel 4-bar profiling mechanism (PFPM) and connection offset of spring is discussed by constructing the steady state analysis matrix equation of PFPM. Additionally, the influence of tilt angle of PFPM and SAD on the stability of the sowing depth was analyzed. Based on the single factor control variable test method, bench and field tests were conducted. The test results show that the SAD increases nonlinearly with the increase in the degree of tilt of PFPM from downward to upward. Under the condition that four springs are installed and the tilt angle of PFPM is between (-20°-20°), the maximum SAD is 485.95 N, 1236.64 N, and 2258.05 N when the spring connection offset is 44 mm, 79 mm, and 115 mm, respectively. When the tilt angle is 8° upward, the GWD increases by 429 N, 575 N, and 984 N, GWD stability increases by 42.31 %, 56.16 %, and 50.29 %, and ditching depth stability increases by 30.00 %, 12.50 %, and 30.00 % compared with that of the control group at the sowing speed of 8, 10, and 12 km/h, respectively. At the sowing speed of 10 km/h, when the PFPM is operated with spring-free and additional springs, the average GWD increases by 353 N, and the stability of GWD and ditching depth increases by 34.38 % and 20.00 %, respectively. The results showed that the tilt upward of PFPM and SAD were beneficial to improve the stability of the GWD and sowing depth of the no-tillage planter row unit. The results not only verify the correctness of theoretical analysis, but also provide theoretical basis for the design and application adjustment of high-speed no-tillage planter.
免耕播种机的播种深度稳定性和一致性较差，尤其是在高速作业时。造成这种情况的一个原因是免耕播种机排种器仿形机构的结构和参数选择不合理。当平行四杆仿形机构（PFPM）的上下连杆与地面平行时，播种深度的稳定性和一致性较好，但在不平的免耕土壤上，这一原则无法满足。为提高免耕播种机排种器限深轮下压力（GWD）和播种深度的稳定性。通过构建PFPM的稳态分析矩阵方程，讨论了弹簧附加下压力（SAD）随平行四杆仿形机构（PFPM）倾斜角度和弹簧连接偏移量的变化规律。此外，分析了PFPM倾斜角度和SAD对播种深度稳定性的影响。基于单因素控制变量试验方法，进行了台架试验和田间试验。试验结果表明，SAD随PFPM从向下到向上倾斜角度的增加呈非线性增加。在安装四个弹簧且PFPM倾斜角度在（-20°-20°）之间的条件下，当弹簧连接偏移量分别为44mm、79mm和115mm时，最大SAD分别为485.95N、1236.64N和2258.05N。当倾斜角度向上为8°时，在播种速度为8、10和12km/h时，与对照组相比，GWD分别增加429N、575N和984N，GWD稳定性分别提高42.31%、56.16%和50.29%，开沟深度稳定性分别提高30.00%、12.50%和30.00%。在播种速度为10km/h时，当PFPM无弹簧和有附加弹簧运行时，平均GWD增加353N，GWD和开沟深度的稳定性分别提高34.38%和20.00%。结果表明，PFPM向上倾斜和SAD有利于提高免耕播种机排种器的GWD和播种深度的稳定性。研究结果不仅验证了理论分析的正确性，也为高速免耕播种机的设计和应用调整提供了理论依据。
