自由端加捻立式青草制辫成型装置设计与试验

Design and Experiment of Vertical Braiding Device with Free-end Twisting

摘要:

为提高青藏高原牧区草辫成型效率并降低人工劳动强度，实现草辫机械化和连续稳定成型，本文设计了一种立式青草制辫成型装置，能够适应不同牧草喂入量，实现自适应连续强制加捻。基于加捻过程的力学关系，构建了喂料辊转速与加捻角速度之间定量模型;通过青燕麦草压缩特性试验，建立了压缩力与压缩位移多项式，决定系数达0.99以上。在此基础上，基于搭建的制辫试验平台进行了三因素三水平正交试验，研究喂料厚度、喂料辊压力、加捻转矩及喂料速度对成型质量的影响，试验结果表明，喂料辊压力需保持为8.26～17.89 kg，加捻转矩为12.43 N·m以上，可实现有效加捻，喂料厚度越大所需压力越大。当喂料加捻辊线速度为0.10 m/s、加捻转速为89 r/min、喂料厚度为0.10 m时，成型草辫最大抗拉强度达到120.58 N。研究表明，在喂入量自适应条件下，立式单捻制辫装置能够实现连续强制加捻，并满足草辫晾晒所需的成型强度要求。

Abstract:

In the pastoral regions of the Qinghai-Tibet Plateau, the traditional method of manually braiding freshly harvested forage for drying is characterized by low efficiency and high labor intensity. To address this challenge and achieve mechanized, continuous, and stable grass braid forming, a vertical green grass braiding device was designed. The device featured an adaptive mechanism that accommodated varying forage feed rates and enabled continuous forced twisting. Based on the mechanical analysis of the twisting process, a quantitative relationship between the feed roller rotational speed and the twisting angular velocity was established. Compression characteristic tests were conducted by using green oat straw, and the relationship between compression force and displacement was accurately modeled by a quartic polynomial equation with a coefficient of determination exceeding 0.99. Utilizing a custom-built experimental braiding platform, a three-factor three-level orthogonal test was performed to investigate the effects of feed thickness, feed pressure, twisting torque, and feed linear speed on the forming quality, with the maximum tensile strength of the formed grass braid as the primary evaluation index. The experimental results indicated that effective twisting was achieved when the feed roller pressure was maintained within the range of 8.26 kg to 17.89 kg and the twisting torque exceeded 12.43 N·m, with higher feed thickness requiring greater applied pressure. Under the optimal combination of operating parameters, specifically a feed-twisting roller linear speed of 0.10 m/s, a twisting speed of 89 r/min, and a feed thickness of 0.10 m, the formed grass braid attained a maximum tensile strength of 120.58 N. The research demonstrated that the proposed vertical single-twist braiding device, operating under adaptive feed conditions, which can successfully achieve continuous forced twisting and produce grass braids with tensile strength sufficient to meet the requirements for subsequent field drying. The findings can provide a theoretical basis and technical reference for the development of mechanized grass braiding equipment for alpine pastoral applications.