Design and experiment of the rotary throwing knife of wine grape cleaning machine

Abstract: Soil clearing operation can be one of the most challenging steps in the wine industry in recent years. The low efficiency can often be found in the single-layer rotary throwing during the soil cleaning operation of wine grapes in northwest China. It is still lacking in the interaction with the soil particles in cold soil, due to empirical design. In this study, a layered rotary throwing soil remover was designed to clarify the interaction between the soil and the rotary throwing knife. The rotary throwing cutter was then realized to balance the different functions of the upper and lower rotary throwing cutters. A dynamic analysis was carried out to determine the overall size of rotary throwing knives using RecurDyn software. Among them, the RecurDyn was a new generation of simulation software for multi-body system dynamics. The movement of the rotary throwing soil cleaning machine was theoretically analyzed to determine the main factors affecting the power consumption and throwing distance of rotary throwing knives. Specifically, the trapezoidal soil ridges in the cross section of 1 000 mm× 600 mm×300 mm ×300 mm (Length × Bottom bottom × Upper bottom × height) were established in the EDEM, according to the agronomic requirements of wine grape planting and soil cleaning. The coupled EDEM and RecurDyn simulation was conducted to analyze the interaction between the discrete particle group of cold-proof soil and the rotary throwing knife. Among them, the test factors were taken as the rotating speed of the rotary throwing knives with the different welding angles, and the forward speed of the whole machine. The evaluation indexes were set as the influence of the soil removal amount and the torque of the rotary throwing knife. An optimal combination of parameters was then obtained after optimization. Then, a three-factor four-level orthogonal experiment was designed to verify the reliability of the model using the analysis of variance. Further verification was also made using a bench test. A series of parameters were also selected in the bench test, including the cleaning rate of the machine, and the torque during operation under the conditions of different welding angles, the rotating and forward speeds, as well as the optimal combination under the conditions of various parameters. The results show that an optimal combination was achieved, where the the soil removal rate was 49.1%, the torque of the rotary throwing knife was 13.09 N·m, and the soil throwing distance was concentrated between 1.52-1.75 m, particularly when the welding angle of the rotary throwing knife was 30°, the rotating speed of the knife was 270 r/min, and the forward speed was 0.4 m/s. Excellent consistency was also obtained with the simulation and experimental. The findings can also provide the theoretical basis and technical reference for the subsequent development of grapevine soil cleaning and vine lifting machine.