水稻钵苗育苗穴盘分离套盘机设计与试验

Design and Experiment of Tray Separating and Embedding Machine for Rice Pot Seedlings

采用工厂化育苗技术进行水稻钵苗育苗时,一般由人工将普通吸塑软穴盘分离然后套入硬托盘后再用于播种,增加了生产成本且劳动强度大。为减少人工成本、降低劳动强度,提高工厂育苗作业自动化,设计了一种适用于工厂化播种流水线的自动分离套盘机。利用真空吸盘吸附倒扣堆叠的软穴盘外侧壁后提升分离,再用翻转机构将分离出的软穴盘翻转180°到达套盘工位,套盘装置中的夹爪机构夹持软穴盘套入硬托盘中完成套盘作业。采用有限元分析软件ANSYS对软穴盘变形量进行分析,采用三维建模软件SolidWorks进行整机三维结构设计,设计了使用8个直径6 mm的风琴型真空吸盘吸附软穴盘作业的真空回路系统,并试制了样机,对不同工况下的软穴盘进行了分离套盘试验。样机试验结果表明,对14×29孔穴规格洁净软穴盘的分离套盘成功率为97%,穴盘表面粘附有水珠或泥土时分离套盘成功率均为98%,分离套盘效率为435盘/h,满足工厂化育苗播种流水线的工作要求,可为提高工厂化水稻钵苗育苗的自动化程度提供参考。

In the nursery factory for rice potseedlings,the soft plastic potseedling tray is embedded into a hard tray manually which increased the cost and the labor intensity.In order to improve the automation level of rice pot seedling nursery factory,an automatic soft tray separating and embedding machine was designed,which can be integrated with the rice seeding pipeline to reduce the cost and improve the efficiency.The automatic soft tray separating and embedding machine mainly consisted of tray separating section and tray embedding section.The separating section included the vacuum clamping mechanism and tray lifting mechanism;the embedding section included the tray turnover mechanism,embedding mechanism and conveying mechanism.According to the pulling force test for separating soft tray,the peak tensile force was varied in the range of 0.807~2.030 N.The vacuum suckers were used to separate the plastic soft trays that were stacked upside down.Then the type and amount of the vacuum suckers was determined.The catching points were set at the outer wall of the holes on the edge of the tray which had enough space for the suckers.By analyzing the overall force applied to the tray,the minimum air pressure for separating the tray was calculated to be 57.924 kPa.After the tray was separated,it was turned 180°by the tray turnover mechanism and sent to the tray embedding section.A hard tray was conveyed and stopped at a fixed position by the conveying mechanism.Then the tray embedding mechanism clamped the tray and moved downward to place the soft tray into the hard tray.The kinematic analysis of the separation mechanism was carried out.The open width variation of the clamping mechanism was determined,so that the time required for the clamping mechanism to clamp the tray can be calculated.The minimum separation height of 20.47 mm was determined based on the tray deformation analysis by ANSYS,the height of the tray and the gap between the trays.According to the design requirements of the overall machine,the control scheme of the system was designed,including the control of the solenoid valve in the air pressure loop and the control of the motor in the mechanism.The overall machine was modeled by using SolidWorks.Based on the machine model,the prototype was manufactured,and the experiments of separating and embedding tray were carried out.220 V single-phase alternative current was used to power the air compressor and the prototype respectively.The pressure regulating valve of the main pneumatic circuit was set to be 0.45 MPa.The experiments were conducted on 14×29 hole trays with clean surface and some water and soil adhered on the surface respectively.The results showed that by using eight 6-mm vacuum suckers,the success rate of separating and embedding 14×29 hole clean seedling tray was 97%.In the case of water and soil adhered on the surface of the tray,the success rate of separating and embedding 14×29 hole seedling tray was 98%.The machine efficiency was 435 trays/h,which could meet the working requirements of the factory seeding line.