【文章內(nèi)容簡(jiǎn)介】 e lowest point while sawtooth had finished cutting straws. Thus, the sawtooth was acted as alternative stress. 3 Materials and method Experimental equipment The experiment was conducted in the soil bin device, of 20mlong, , , the available working journey of vehicle was 16 m, and the working velocity of vehicle was from m/s to m/s. And other equipment included: AKC205 type wring sensor, the sawing antiblocking mechanism, control tank, puter operation platform, etc. Experimental materials The average height and diameter of corn straw is m, 25. 6 mm, respectively. It is made up of leaves and skin and marrow. The weight of leaves and marrow occupy above 55% of whole straw and their mechanical intension are much lower。 and the weight of skin made up of scarfskin and bunchy anization occupy 35% or so, the mechanical intension of skin is much higher up to 90 MPa of portrait resistant pulling intension and 3 MPa of landscape orientation resistant pulling intension by measurement, which was essential theory basis for the sawtooth blade to select landscape orientation principle in order to decrease power consumption. Experimental methods The sawing antiblocking mechanism was hung up in the soil bin device, and its ascending was controlled by hydraulic pressure system, and the wringM measured by wring sensor was automatically noted in puter, repeat three times, and then the power consumption could be calculated by expressionP=M n/9549, the cutting rateηcould be calculated by expressionη= (GG0)/G100%, where,G—— the total mass of effective width/kg,G0—— total mass of the straws cut down between adjacent openers. 4 Results and discussion Experiments and analysis of rotation direction of the sawtooth blade for cutting quality Some experiments were done by clockwise and counterclockwise rotation of the sawtooth blade in the soil bin device. The results are listed in Table 1. Table 1 Experimental results of rotation direction of the sawtooth blade Table 1 showed that the way of cutting straws at counterclockwise rotation would be of benefit to improve cutting quality and throwing effect, and boost up adaptability of weight of different stubble mulch. Therefore, counterclockwise rotation direction of the sawtooth blade had been determined. Effect of the rotation speed on cutting quality The experiments were done by selecting velocity m/s of vehicle and interval 5 mm of the moved and fixed blade, and spacing 20 mm between the sawtooth and ground as well as weight 11250 kg/hm2of the straws mulch, experimental results are shown in . The results indicated that the power consumption and cutting rate would increase with rising of rotation speed of the sawtooth blade. Because the wring values of cutting straws were equal basically on the same working condition, the cutting rate could be up to 100% while the rotation speed of the sawtooth blade was above 650 r/min. It was because the probability rate of the sawtooth blade to cut straws 67 Liao Qingxi et al: Design of antiblocking mechanism for notillage planter would increase with rising of rotation speed whenweight of straws was fixed. Relationships among rotation speed, cutting rate and power consumption Effect of the straw moisture on cutting quality The straw moisture of the same crops is different for different autumn and reaping time. The moisture were 20%, %, % and % respectively, after corn straws had been placed in field for different periods. Experiments were done by selecting velocity m/s of vehicle and interval 5 mm between the moved and fixed blade and spacing 20 mm between sawtooth and ground, and rotation speed 650 r/min as well as mass 11250 kg/hm2of straws mulch, the results were shown in . Results of straws moisture for cutting rate and power consumption Experimental results show that power consumption decreased with increasing of straw moisture and cutting rate of straws increased with increasing of straws moisture on the same working condition, which had connected importantly with different moisture of straws. Straws would take on bigger hardness and best firmness and fine brittleness when straws moisture was in higher, which demonstrated that it had been easy to finish to cut straws. But straws would take on tired and soft status for fine flexible and toughness when straw moisture was lower, so it would be easy to bring to tearing and wrapping. The sawtooth blade had fine cutting quality and higher cutting rate while straws moisture was up to % (). However the sawtooth blade had taken on tearing while straw moisture was up to 20%(). of interval between the fixed and moved blade and velocity of vehicle on cutting quality Experiments were done by selecting velocity m/s of the vehicle and spacing 20 mm between sawtooth and ground, and rotation speed 650 r/min as well as weight 11250 kg/hm2of the straws mulch, experimental results are shown in . The results proved that power consumption increased with increasing of velocity of vehicle on the same working condition. The power consumption increased with increasing interval between the fixed and moved blade and no fixed blade, at the same time, power consumption with interval 10mm between the fixed and moved blade was equal basically to that of without the fixed blade, and the power consumption was decreased with interval 5 mm between the fixed and moved blade. At the same time, cutting quality of interval 5 mm between the fixed and moved blade was excel to that of above 5 mm interval. Its reasons lied in that straws would be cut down pletely while the small interval between the fixed and moved blade, the bigger interval between the fixed and moved blade or near diameter of corn straws, corn straws could be embedded into sawtooth and participated in cutting again, so feeding quantities of straws were increased. A