香蕉串果夹持机构设计与试验

目的 香蕉收获机械装备需要承担大质量蕉串，设计一种夹持机构在保证动作灵活有效的同时，具有较高的强度和可靠的夹持力。方法 提出一种用于采摘香蕉的内掌带钉抱掌夹持机构，对影响抱掌夹持力的不同组合因素进行了夹持效果测试，搭建了夹持试验平台。选择影响夹持效果的气缸压力、钉子数量和钉子排列方式3个主要因素，采用单因素试验和响应曲面法进行夹持力效果测试。结果 在气缸压力试验中，当气缸压强为0.4 MPa时，对应的拉力为500 N左右，最接近蕉柄和抱掌之间的最大静摩擦力，可以稳定夹持。在钉子排列方式的试验过程中，矩形可承受的摩擦力最大，为800 N，大于蕉柄和抱掌之间的最大静摩擦力，可以获得稳定的夹持效果。在钉子数量的试验过程中，钉子数量分别为8和10个时获得的拉力比较接近，原因可能是香蕉柄不是规则的圆柱形，导致圆形抱掌上的钉子未必全部扎进蕉柄内，钉子数量为8或10个时，只有6个钉子扎进蕉柄进行有效的夹持；钉子数量超过10个时，拉力不升反降，出现该现象的原因可能是钉子越多，出现互相干扰的现象越严重，导致有效钉子的数量不升反降。结论 影响夹持机构夹持力效果的因素：气缸压力>钉子排列方式>钉子数量，最佳参数组合：气缸压强0.4 MPa、钉子数量10个、矩形排列方式。本文为平地蕉园香蕉收获机械装备关键部件夹持机构的设计提供了理论参考。

Design and test of banana skewer fruit holding mechanism

Objective Banana harvesters are equipped to carry large loads of bunches. We propose a nail holding mechanism for bananas which posses high strength and reliable clamping force while ensuring flexible and effective operation.Method An inner palm holding mechanism with nails for picking bananas was designed, the clamping effects of different combination factors affecting the gripping force were tested, and the clamping test platform was built. The three main factors of cylinder pressure, the number and arrangement of nails affecting the clamping effect were selected, and the single factor experiment and response surface method were used to test the clamping force.Result In the cylinder pressure test, when the cylinder pressure was 0.4 MPa, the corresponding tension was about 500 N closest to the maximum static friction force between the banana handle and the palm, and banana could be clamped stably. In the test of nail arrangement, the friction that the rectangle could withstand was the maximum with a value of 800 N, which was greater than the maximum static friction force between the banana handle and the palm, and the stable clamping effect could be obtained. In the test of nail number, when the numbers of nails were eight and ten, their pulls closed to. The reason may be that the banana handle is not a regular cylindrical shape, so that the nails on the round holding palm may not be all inserted into the banana handle. When the number of nails was eight or ten, only six nails plunged into banana handle and effectively clamped. When the number of nails exceeded ten, the tension dropped instead of rising. The reason for this phenomenon may be that the more nails there are, the more serious the mutual interference occurs, and the number of effective nails decreases instead of rising.Conclusion The factors influencing the clamping force effect of clamping mechanism are cylinder pressure > nail arrangement > number of nails. The optimal parameter combination is 0.4 MPa cylinder pressure, ten nails and rectangular arrangement. This paper provides a theoretical reference for the design of clamping mechanism of key components of banana harvester equipment in flat banana plantation.