打结器夹绳-绕扣-钳咬动作参数分析与打结试验

Parameters Analysis of Rope-holding Motion,Knot-winding Motion,Rope-biting Motion of Knotter and Knotting Tests

通过对打结器夹绳-绕扣-钳咬动作的运动学建模,解析描述了捆绳夹持、绕扣成环和准确钳咬的动作时序关系和位置关系,分析了打结嘴和夹绳盘动作时序差φ和打结嘴轴线与主轴轴线夹角α取不同值时对夹绳、绕扣和钳咬动作的影响,并对夹绳运动的放绳作用进行分析,建立了捆绳钳咬前牢固夹持的受力条件和捆绳钳咬后允许捆绳沿夹绳盘轴向滑移而不被拉断的受力条件。结果表明当α与φ分别为90°与24°时,捆绳可以被稳定夹持、成功绕扣和准确钳咬,物理样机的动作试验验证了理论建模的正确性。不捆扎物料的打结器成结率为100%,捆扎小麦秸秆的成结率达到99.25%,表明打结器动作参数匹配合理。

By establishing kinematical model of rope-holding motion, knot-winding motion, rope-biting motion of the knotter, timing sequence and position relation of rope-holding, successful knot-winding and accurate rope-biting were described analytically. The effects of the timing sequence difference value φbetween the motion of knotting hook and the motion of rope-holding plate and the angle α between the knotting hook axis and principal axis on rope-holding motion, knot-winding motion, rope-biting motion were analyzed. After the rope-loosening, function of rope-holding motion was analyzed. The mechanic condition of firm rope-holding before rope-biting, as well as the mechanic condition of allowing the rope to slip along axle direction of rope-holding plate and avoiding breaking the rope after rope-biting were established respectively. The results showed that the rope could be held firmly, wound successfully and bitten accurately when the value of ct and φ are 90° and 24° respectively. The motion test of the physical prototype validated the theoretical model accuracy of rope-holding motion, knot-winding motion and rope- biting motion. The results of knotting test without bundling straws and with bundling wheat straws showed that the knot-tied rate of knotter may reach 100% and 99.25% respectively, which proved that the motion parameters of the knotter were matched reasonably.