趙建國(guó),王 安,馬躍進(jìn),李建昌,郝建軍,聶慶亮,龍思放,楊前鋒
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深松旋耕碎土聯(lián)合整地機(jī)設(shè)計(jì)與試驗(yàn)
趙建國(guó),王 安,馬躍進(jìn),李建昌,郝建軍,聶慶亮,龍思放,楊前鋒
(河北農(nóng)業(yè)大學(xué)機(jī)電工程學(xué)院,保定 071001)
為減少耕作阻力、改善土壤耕層結(jié)構(gòu)、提高碎土率,該文對(duì)聯(lián)合整地機(jī)的深松部件、碎土機(jī)構(gòu)進(jìn)行設(shè)計(jì),設(shè)計(jì)了入土角度可控的自激振動(dòng)深松鏟,并建立了自激振動(dòng)深松鏟的運(yùn)動(dòng)學(xué)模型和力學(xué)模型,確定彈簧行程為15 mm、負(fù)載為7 500~15 000 N,并確定了彈簧的結(jié)構(gòu)參數(shù)。設(shè)計(jì)了具有二次碎土功能的籠狀碎土輥,并依據(jù)農(nóng)藝要求確定了其結(jié)構(gòu)參數(shù)。通過(guò)室內(nèi)土槽試驗(yàn),驗(yàn)證了自激振動(dòng)深松鏟的減阻效果和耕作質(zhì)量,并對(duì)整機(jī)的作業(yè)質(zhì)量進(jìn)行了田間測(cè)試。土槽試驗(yàn)結(jié)果表明:與對(duì)照相比,自激振動(dòng)深松鏟平均減阻9.22%,土壤蓬松度和土壤擾動(dòng)系數(shù)分別為26.16%和77.21%,減阻效果明顯,作業(yè)效果較好。田間試驗(yàn)結(jié)果表明:聯(lián)合整地機(jī)的深松深度穩(wěn)定系數(shù)、旋耕深度穩(wěn)定系數(shù)、地表平整度和植被覆蓋率分別為94.92%、92.50%、1.17 cm和93.36%;籠狀碎土輥在整個(gè)試驗(yàn)過(guò)程中未出現(xiàn)土壤粘附和擁堵現(xiàn)象,碎土率為84.18%,加裝普通齒狀碎土輥機(jī)具的碎土率為71.41%,籠狀碎土輥的碎土率提高了12.77個(gè)百分點(diǎn),碎土效果明顯改善。深松旋耕碎土聯(lián)合整地機(jī)減阻效果明顯、整地質(zhì)量好,可有效改善土壤的耕層結(jié)構(gòu),降低土壤容重,提高蓄水保墑能力。
農(nóng)業(yè)機(jī)械;設(shè)計(jì);深松;旋耕;籠狀碎土輥;自激式振動(dòng)
田間犁底層的存在,會(huì)影響物質(zhì)的傳遞、能量的轉(zhuǎn)移及作物根系下伸,從而降低作物產(chǎn)量。深松作業(yè)可有效打破犁底層,提高土壤的蓄水保墑能力、作物根系下伸和營(yíng)養(yǎng)物質(zhì)的傳遞,從而提高作物產(chǎn)量[1]。深松作業(yè)雖有積極的增產(chǎn)作用,但深松作業(yè)的能耗一般為作物收獲機(jī)械的3~5倍[2];雖然傳統(tǒng)的深松旋耕作業(yè)模式碎土效果已經(jīng)很明顯,但在華北平原地區(qū),通常需要2次進(jìn)地2遍旋耕后才進(jìn)行播種作業(yè),降低作業(yè)效率的同時(shí),容易造成土壤的二次壓實(shí),影響作業(yè)效果。因此深松旋耕整地機(jī)具的深松減阻和碎土效果一直是研究重點(diǎn)。
針對(duì)深松作業(yè)阻力大問(wèn)題,研究學(xué)者設(shè)計(jì)了振動(dòng)深松機(jī),在土壤作業(yè)過(guò)程中,使深松鏟產(chǎn)生一定頻率的振動(dòng),從而疏松土壤達(dá)到減阻目的[3-6];Araya等[7]在深松機(jī)具上增加高壓氣體噴射裝置,在深松鏟表面噴射出空氣或水,從而降低土壤對(duì)深松鏟的摩擦力[7];Larson等[8]利用電位差原理,使深松鏟和土壤接觸面上形成一層薄水膜,水膜可以起潤(rùn)滑作用,從而減少摩擦降低阻力;鄭侃等[9]根據(jù)耕作層、犁底層和心土層的土壤性質(zhì),設(shè)計(jì)了具有不同滑切角和切削刃角的深松鏟柄,可有效降低耕作阻力,提高作業(yè)質(zhì)量;趙淑紅等[10],采用離散元軟件獲得深松鏟鏟尖在土壤中的運(yùn)動(dòng)曲線,依據(jù)運(yùn)動(dòng)曲線設(shè)計(jì)了擬合曲線型深松鏟,其土壤擾動(dòng)量和耕作阻力明顯降低;另外,研究學(xué)者通過(guò)對(duì)挖掘動(dòng)物和海洋生物的幾何結(jié)構(gòu)和生物學(xué)特性進(jìn)行研究,發(fā)現(xiàn)其具有明顯的減阻效果,進(jìn)而設(shè)計(jì)發(fā)明了仿生鏟[11-13]。綜合來(lái)看,針對(duì)深松減阻問(wèn)題,國(guó)內(nèi)外有很多相關(guān)研究,但因自激式振動(dòng)深松機(jī)中彈簧元件的強(qiáng)度和抗疲勞特性要求高、制作較復(fù)雜、振動(dòng)參數(shù)不易控制等問(wèn)題,國(guó)內(nèi)振動(dòng)深松機(jī)多以強(qiáng)迫式振動(dòng)為主;同時(shí)由于自激振動(dòng)深松鏟的彈簧元件與深松鏟柔性連接,因耕作阻力的變化,使深松鏟在作業(yè)過(guò)程中入土角度多變,從而影響裝置的減阻效果和降低深松的穩(wěn)定性。
普通齒狀碎土輥在黏性或潮濕土壤中粘土嚴(yán)重,一般是在碎土輥上加裝一排定刀,去除粘附在碎土輥上的土壤。但定刀的設(shè)計(jì)會(huì)影響碎土輥的正常工作,增加阻力消耗的同時(shí)降低碎土質(zhì)量。
為了降低耕作阻力和提高碎土質(zhì)量,本文對(duì)深松旋耕整地機(jī)關(guān)鍵部件進(jìn)行改進(jìn),分別設(shè)計(jì)了入土角可控的自激振動(dòng)深松鏟和具有二次碎土功能的籠狀碎土輥,并對(duì)自激振動(dòng)深松鏟和深松旋耕碎土聯(lián)合整地機(jī)分別進(jìn)行了室內(nèi)土槽試驗(yàn)和田間試驗(yàn),驗(yàn)證了自激振動(dòng)深松鏟的減阻和作業(yè)性能,并對(duì)比分析了加裝籠狀碎土輥的機(jī)具作業(yè)效果。
如圖1所示,機(jī)具主要由旋耕機(jī)、自激振動(dòng)深松鏟和籠狀碎土輥3部分組成。工作時(shí),深松旋耕碎土聯(lián)合整地機(jī)懸掛于拖拉機(jī)后方,一次性作業(yè)可完成旋耕、深松、碎土和鎮(zhèn)壓等工序,有效寬幅為2 300 mm。根據(jù)國(guó)家標(biāo)準(zhǔn)和農(nóng)藝要求,其深松深度≥300 mm,整地深度≥120 mm,深松深度穩(wěn)定性系數(shù)≥80%,整地深度穩(wěn)定性系數(shù)≥85%,耕后地表平整度≤40 mm,土壤擾動(dòng)系數(shù)≥50%,土壤蓬松度10%~40%,植被覆概率≥60%,碎土率≥60%[14-15]。因?yàn)樯钏勺鳂I(yè)的土壤擾動(dòng)寬度約為深松深度的2倍[16],因此機(jī)具的鏟間距設(shè)計(jì)為600 mm,其他主要參數(shù)如表1所示。
圖1 深松旋耕碎土聯(lián)合整地機(jī)結(jié)構(gòu)示意圖
表1 深松旋耕碎土聯(lián)合整地機(jī)主要結(jié)構(gòu)參數(shù)
先將深松旋耕碎土聯(lián)合整地機(jī)通過(guò)三點(diǎn)懸掛裝置掛裝在拖拉機(jī)尾部,并通過(guò)彈簧預(yù)緊端蓋調(diào)整彈簧的預(yù)緊力和深松鏟的入土角;然后調(diào)整碎土輥離地高度,使旋耕、深松深度達(dá)到農(nóng)藝要求;深松旋耕作業(yè)時(shí),位于旋耕機(jī)底部的深松鏟尖將犁底層打破,深松隆起的土壤則由旋耕機(jī)破碎平整,深松鏟柄位于旋耕機(jī)后部,可避免秸稈雜草在鏟柄的纏繞和堵塞;最后由碎土輥對(duì)深松旋耕作業(yè)后的土壤進(jìn)行碎土和鎮(zhèn)壓,形成有利于播種和植物生長(zhǎng)的種床。
如圖2所示,入土角可控自激振動(dòng)深松鏟主要由彈簧激振裝置、深松鏟連接板和深松鏟3部分組成。深松鏟由螺栓固定在深松機(jī)架上,彈簧激振裝置和深松鏟由連接板連接。因地面凹凸不平和土壤阻力的變化,深松過(guò)程中深松鏟圍繞連接板上的第一銷釘順時(shí)針轉(zhuǎn)動(dòng),從而壓縮彈簧激振裝置中的彈簧,使深松鏟發(fā)生小幅度振動(dòng)。
圖2 自激振動(dòng)深松鏟結(jié)構(gòu)示意圖
深松鏟的結(jié)構(gòu)參數(shù)參照課題組的前期設(shè)計(jì)[17]。彈簧激振裝置結(jié)構(gòu)組成如圖3所示,主要由預(yù)緊端蓋、彈簧端蓋、外簧、內(nèi)簧、彈簧芯軸和固定銷組成。受土壤阻力變化的影響,深松鏟圍繞第一銷釘順時(shí)針轉(zhuǎn)動(dòng),彈簧激振裝置中的彈簧受力壓縮。當(dāng)耕作阻力過(guò)大時(shí),第三銷釘與直槽口底部接觸,深松鏟的入土角度被限制到最大值。直槽口的設(shè)計(jì)可將深松鏟的入土角控制在最佳范圍內(nèi),保持深松深度的穩(wěn)定性,并使彈簧不出現(xiàn)完全壓縮的狀態(tài),保證彈簧元件工作的可靠性。彈簧元件參數(shù)的選取由深松鏟運(yùn)動(dòng)狀態(tài)和負(fù)載決定,是整個(gè)裝置設(shè)計(jì)的核心,因此需要對(duì)自激振動(dòng)深松鏟進(jìn)行運(yùn)動(dòng)學(xué)和力學(xué)分析。
2.1.1 自激振動(dòng)深松鏟運(yùn)動(dòng)學(xué)分析
圖3 彈簧激振裝置結(jié)構(gòu)示意圖
注:1為深松鏟未振動(dòng)狀態(tài),2為深松鏟振動(dòng)角度為α?xí)r的振動(dòng)狀態(tài);A為固定梁;O、B和C點(diǎn)分別為第一、二和三銷釘中心點(diǎn);B¢點(diǎn)為深松鏟振動(dòng)角度為α?xí)r的點(diǎn)B位置;l1為點(diǎn)O與點(diǎn)B的距離,l1=172 mm;l2為點(diǎn)O與點(diǎn)C的距離,l2=278 mm;l3為點(diǎn)C與點(diǎn)B的距離,mm;l3¢為點(diǎn)C與點(diǎn)B¢的距離,mm;β為OB與OC的夾角,β=51.64°;g為深松鏟未振動(dòng)時(shí)的入土角,(°);g¢為深松鏟振動(dòng)時(shí)的入土角,(°);α為裝置從狀態(tài)1到狀態(tài)2時(shí)的振動(dòng)角,即OB與OB¢的夾角,(°)。下同。
由圖4可求得彈簧壓縮行程為:
(3)
因自激振動(dòng)深松鏟具有唯一確定的運(yùn)動(dòng),故深松鏟的入土角是影響彈簧壓縮行程的主要參數(shù)。參考文獻(xiàn)[19-23],深松鏟入土角的變化范圍為23°~28°。通過(guò)對(duì)機(jī)構(gòu)的自由度分析可知,自激振動(dòng)深松鏟有唯一的運(yùn)動(dòng)方向,根據(jù)入土角度的取值范圍,可以求出自激振動(dòng)深松鏟的振動(dòng)角的最大值為:
由式(5)求得振動(dòng)角的最大值為5°,代入式(2)~式(4)中,求得=14.99 mm,圓整取彈簧壓縮行程為15 mm。
2.1.2 自激振動(dòng)深松鏟力學(xué)分析
自激振動(dòng)深松鏟的受力簡(jiǎn)圖如圖5所示。深松鏟和深松鏟連接板之間的連接屬于剛性連接,故將兩者視為一體,為了簡(jiǎn)化模型將深松鏟的受力位置選為鏟尖。根據(jù)力與力臂的關(guān)系可求得彈簧受到的壓力為:
由式(6)求得彈簧的負(fù)載為7 500~15 000 N。因深松作業(yè)過(guò)程中,需要保證壓縮彈簧不能出現(xiàn)傾斜狀態(tài),同時(shí)考慮到載荷較大、安裝空間受限的問(wèn)題,最終選用組合彈簧作為自激振動(dòng)彈簧,彈簧材料選用60Si2Mn,類型為YI型。根據(jù)機(jī)械設(shè)計(jì)手冊(cè)[25]求得內(nèi)外壓縮彈簧的相關(guān)參數(shù)如表2所示。
注: D為深松鏟鏟尖;l4為點(diǎn)O與點(diǎn)D的距離,l4=515 mm;F力為土壤對(duì)深松鏟的作用阻力,N;P為深松鏟連接板對(duì)彈簧的壓力,N。
表2 彈簧參數(shù)
為提高碎土輥碎土質(zhì)量,將菱狀碎土齒交錯(cuò)焊接在帶有間隙的圓柱滾筒上,設(shè)計(jì)了籠狀碎土輥。工作時(shí),首先由碎土齒外齒將土壤初次破碎,由于圓柱滾筒之間有一定的間隙,大塊土壤會(huì)由縫隙進(jìn)入碎土輥內(nèi)部,而不會(huì)粘附在圓柱滾筒上,進(jìn)入碎土輥內(nèi)部的大塊土壤在碎土齒內(nèi)齒的作用下再進(jìn)行二次破碎?;\狀碎土輥結(jié)構(gòu)如圖6所示。
1. 圓柱滾筒 2. 碎土齒外齒 3. 碎土齒內(nèi)齒
籠狀碎土輥類似于碎土類圓盤耙,其相關(guān)參數(shù)可按照?qǐng)A盤耙的設(shè)計(jì)公式計(jì)算。根據(jù)經(jīng)驗(yàn)公式籠狀碎土輥直徑為
=max(7)
式中為徑深比系數(shù),=3~7[13];max為最大作業(yè)深度,mm。
為保證碎土效果,取最大值7。根據(jù)小麥和玉米的常規(guī)播種深度30~50 mm,max=50 mm。綜上,由式(7)求得籠狀碎土輥直徑=450 mm。
對(duì)于比較堅(jiān)硬的土塊,大塊的土壤不易破碎,土壤堆積后易形成空穴,不利于種子后期發(fā)芽。而尖的碎土齒可在碎土輥的自重作用下,利用鋒利的齒尖將大塊土壤有效破碎[26],因此將碎土齒設(shè)計(jì)成菱形,其形狀如圖7所示。
碎土齒的厚度為[13]
=(0.008~0.02)(8)
由式(8)求得的取值范圍為3.6~9 mm,考慮標(biāo)準(zhǔn)板材厚度、耐磨性和銑齒的需要,取=10 mm;研究表明觸土部件切削刃角為45°時(shí),作業(yè)阻力最小[27],但切削刃角越小,越容易造成刃口的崩裂和卷邊;為碎土齒的入土角,越小,齒尖與土壤接觸單位面積上的壓強(qiáng)更大,齒尖越容易發(fā)生失效。為保證碎土齒的使用壽命,考慮齒厚,設(shè)計(jì)碎土齒的切削刃角和入土角均為60°。
標(biāo)準(zhǔn)要求作業(yè)后的任意邊長(zhǎng)小于40 mm土塊質(zhì)量占比不能小于60%[14],據(jù)此確定相鄰2個(gè)碎土齒間隙為40 mm。為減少碎土齒安裝數(shù)量、避免因單根圓型管材焊接碎土齒數(shù)量過(guò)多導(dǎo)致圓柱滾筒變形,如圖8所示將碎土齒按照交錯(cuò)排列方式等距安裝在圓柱滾筒上,并根據(jù)碎土輥總長(zhǎng)、碎土齒齒厚和交錯(cuò)相鄰2個(gè)碎土齒間隙,碎土齒沿軸向和徑向間隔排列,共188個(gè)。
注:1為碎土齒與圓柱滾筒焊接孔,直徑φ=30mm;hmax為碎土齒最大作業(yè)深度,hmax=50mm;s為碎土齒的厚度,mm;δ為碎土齒的入土角,(°);θ為碎土齒的切削刃角,(°)。下同。
注:●為碎土齒安裝位置。
3.1.1 試驗(yàn)?zāi)康呐c設(shè)備
為驗(yàn)證自激振動(dòng)深松鏟設(shè)計(jì)的合理性,進(jìn)行室內(nèi)土槽試驗(yàn)。試驗(yàn)以耕作阻力、土壤蓬松度和擾動(dòng)系數(shù)為指標(biāo),綜合評(píng)定自激振動(dòng)深松鏟的減阻效果和工作性能。如圖9所示,試驗(yàn)在河北農(nóng)業(yè)大學(xué)土槽試驗(yàn)室進(jìn)行,所用土壤為華北平原地區(qū)農(nóng)田壤土,試驗(yàn)用土槽試驗(yàn)臺(tái)為哈爾濱博納科技有限公司研制(TCC-Ⅱ電力四驅(qū)土槽試驗(yàn)車),土槽尺寸20 m′2 m′1 m(長(zhǎng)′寬′高)。
3.1.2 試驗(yàn)方法
為近似模擬真實(shí)的田間土壤狀態(tài),試驗(yàn)前將土壤表面20 cm深度的土壤取出,并將底層土壤壓實(shí)。土壤回填鋪平后,用旋耕機(jī)將表層土壤打碎后,再用輥?zhàn)訅簩?shí)[28]。根據(jù)以往田間測(cè)量數(shù)據(jù),使制備土壤的含水率達(dá)到10%~20%,0~20 cm土壤堅(jiān)實(shí)度達(dá)到0.5~2 MPa,20~40 cm堅(jiān)實(shí)度達(dá)到2~4 MPa。試驗(yàn)深松鏟通過(guò)U型卡子固定在測(cè)力架上,將自激振動(dòng)深松鏟中彈簧激振裝置的內(nèi)外壓縮彈簧用套筒替代作為對(duì)照深松鏟,試驗(yàn)用深松鏟如圖9b、圖9c所示。深松鏟耕作深度為300 mm,速度為1 km/h,測(cè)定中間穩(wěn)定段耕作阻力數(shù)據(jù),進(jìn)行3次重復(fù)試驗(yàn)。并按圖9d、9e、9f測(cè)定自激振動(dòng)深松鏟的作業(yè)質(zhì)量,在垂直作業(yè)方向橫跨工作幅寬地表建立水平基準(zhǔn),間隔30 mm分別測(cè)定耕前地表線、耕后地表線和溝底線,并采用繪圖軟件繪制深松后壟溝橫斷面,由式(9)、式(10)計(jì)算土壤蓬松度和擾動(dòng)系數(shù)。試驗(yàn)數(shù)據(jù)采用Duncan氏新復(fù)極差法計(jì)算均值和標(biāo)準(zhǔn)誤差。
3.1.3 土槽試驗(yàn)結(jié)果與分析
圖10為3次重復(fù)試驗(yàn)中第1個(gè)行程的2種深松鏟耕作阻力對(duì)比曲線(另外2個(gè)行程的阻力曲線分布趨勢(shì)類似)。由圖10可知,耕作阻力隨時(shí)間變化呈現(xiàn)不規(guī)律的上下浮動(dòng),主要是由于土壤條件差異造成??傮w上,自激振動(dòng)深松鏟的耕作阻力小于對(duì)照深松鏟耕作阻力。表3為3次重復(fù)試驗(yàn)穩(wěn)定段的耕作阻力。試驗(yàn)數(shù)據(jù)表明,與對(duì)照相比,自激振動(dòng)深松鏟耕作阻力明顯變小,分別下降8.87%、9.75%和9.04%,試驗(yàn)結(jié)果表明自激振動(dòng)深松鏟減阻效果明顯,與對(duì)照深松鏟存在顯著性差異,平均減阻9.22%。
圖10 耕作阻力試驗(yàn)曲線
表3 耕作阻力試驗(yàn)數(shù)據(jù)
注:表中同列不同字母表示在=0.05水平上差異顯著。
Note: Different letters of the same column in the table indicated significant differences at=0.05 .
表4為測(cè)定土壤蓬松度和擾動(dòng)系數(shù)。作業(yè)機(jī)質(zhì)量標(biāo)準(zhǔn)評(píng)價(jià)指標(biāo)要求土壤蓬松度應(yīng)不大于40%而土壤擾動(dòng)系數(shù)應(yīng)不小于50%[14]。試驗(yàn)測(cè)定的土壤蓬松度為26.16%,土壤擾動(dòng)系數(shù)為77.21%,均滿足作業(yè)質(zhì)量標(biāo)準(zhǔn)要求,結(jié)果表明自激振動(dòng)深松鏟作業(yè)效果良好。其中第3個(gè)行程的深松斷面圖如圖11所示,斷面呈倒三角形,底部動(dòng)土范圍小,頂部動(dòng)土范圍大,能有效打破犁底層同時(shí)疏松表面土壤,利于土壤的蓄水保墑和植物根系的生長(zhǎng)。
表4 土壤蓬松度和土壤擾動(dòng)系數(shù)
注:A為耕前地表線到理論溝底線的剖面面積,cm2;A為耕后地表線到理論溝底線的剖面面積,cm2;A為耕前地表線到實(shí)際溝底線的剖面面積,cm2。
Note:Ais sectional area between terrain line before subsoiling and theoretical subsoiling bottom line, cm2;Ais sectional area between terrain line after subsoiling and theoretical subsoiling bottom line, cm2;Ais sectional area between terrain line before subsoiling and real subsoiling bottom line, cm2.
圖11 深松后壟溝橫斷面
為驗(yàn)證籠狀碎土輥的碎土效果和深松旋耕碎土聯(lián)合整地機(jī)的作業(yè)質(zhì)量,于2018年9月在河北省深澤縣農(nóng)田進(jìn)行了整機(jī)田間試驗(yàn),如圖12所示。根據(jù)中華人民共和國(guó)工業(yè)和信息化部發(fā)布的JB/T 10295-2014《深松整地聯(lián)合作業(yè)機(jī)》作業(yè)性能評(píng)定指標(biāo)[14]和可用于表征土壤物理狀態(tài)的相關(guān)參數(shù)[4],試驗(yàn)選取土壤容重、土壤含水率、深松深度及穩(wěn)定性、整地深度及穩(wěn)定性、碎土率和植被覆蓋率綜合評(píng)價(jià)深松旋耕碎土聯(lián)合整地機(jī)作業(yè)質(zhì)量。
3.2.1 試驗(yàn)條件與方法
試驗(yàn)地總面積約0.1 hm2,土壤質(zhì)地為壤土,作業(yè)前土壤含水率為15.89%,容重為1.47 g/cm3。試驗(yàn)設(shè)備主要包括雷沃歐豹M1254-G拖拉機(jī)、環(huán)刀(體積100 cm3)、塑封袋(長(zhǎng)′寬=15 cm′10 cm)、DGG-9626A電熱恒溫鼓風(fēng)干燥箱(北京雅士林試驗(yàn)設(shè)備有限公司)、ACS電子秤(上海剴任電子有限公司,量程30 kg,精度1 g)、BSA224S電子天平(德國(guó)賽多利斯,量程220 g,精度0.1 mg)、鋼板尺和卷尺(精度1 mm)等。
將試驗(yàn)田劃分為長(zhǎng)30 m,寬為機(jī)具1.5倍的小區(qū),前10 m和后10 m為加速和減速階段,中間10 m為數(shù)據(jù)測(cè)試區(qū)。試驗(yàn)重復(fù)3次,采用環(huán)刀測(cè)量作業(yè)前、后的土壤容重和含水率。并根據(jù)JB/T 10295-2014《深松整地聯(lián)合作業(yè)機(jī)》鑒定方法測(cè)量計(jì)算深松深度穩(wěn)定性、整地深度穩(wěn)定性、碎土率和植被覆蓋率4項(xiàng)指標(biāo)[14]。
圖12 田間試驗(yàn)
3.2.2 土壤容重和含水率測(cè)定結(jié)果分析
采用環(huán)刀在每個(gè)行程沿機(jī)具前進(jìn)方向等距選3點(diǎn)取樣,為保證數(shù)據(jù)的準(zhǔn)確性在測(cè)量點(diǎn)和其左右10 cm處,共取樣3點(diǎn),用其平均值表示該點(diǎn)數(shù)值。土壤容重和含水率測(cè)定結(jié)果如表5所示。由表5可知,作業(yè)前10~20 cm存在一層犁地層,容重為1.57 g/cm。作業(yè)后犁底層消失,各層容重均有下降,其中10~20 cm減少最顯著為0.22 g/cm;作業(yè)后0~10 cm的容重和含水率最低,可能是因?yàn)樯钏尚鳂I(yè)對(duì)表層土壤的擾動(dòng)最大,表層土壤松軟從而更易跑墑,造成土壤容重和含水率最低。
表5 作業(yè)前后土壤容重和含水率
3.2.3 深松、旋耕深度和穩(wěn)定性測(cè)定結(jié)果分析
在每個(gè)行程的測(cè)試區(qū),等距取10個(gè)點(diǎn),測(cè)定深松深度,結(jié)果見(jiàn)表6;在每個(gè)行程隨機(jī)取3個(gè)點(diǎn),每個(gè)點(diǎn)左右各測(cè)11個(gè)點(diǎn),測(cè)定旋耕深度,結(jié)果見(jiàn)表7。由表6和表7可知,深松深度為37.73 cm,穩(wěn)定系數(shù)為94.92%;整地深度為15.67 cm,穩(wěn)定系數(shù)為92.50%,地表平整度為1.17 cm,各項(xiàng)指標(biāo)均滿足作業(yè)質(zhì)量標(biāo)準(zhǔn)要求[14]。
表6 深松深度和穩(wěn)定性
表7 整地深度和穩(wěn)定性
3.2.4 植被覆蓋率和碎土率測(cè)定結(jié)果分析
旋耕可將雜草和秸稈與土壤混合,但在作業(yè)過(guò)程中會(huì)有少量雜草和秸稈未被土壤完全掩埋裸露在地面。較高的植被覆蓋,影響播種機(jī)的作業(yè)性能,從而影響播種質(zhì)量。故在每個(gè)行程測(cè)試區(qū),隨機(jī)取1個(gè)點(diǎn),測(cè)定1 000 mm′1 000 mm(長(zhǎng)′寬)地表內(nèi)的耕前和耕后的植被質(zhì)量,耕前和耕后的植被質(zhì)量差值與耕前植被質(zhì)量的比值則為該測(cè)試點(diǎn)的植被覆蓋率,測(cè)試數(shù)據(jù)計(jì)算整理后見(jiàn)表8。由表8可知植被覆蓋率為93.36%;同樣在每個(gè)行程隨機(jī)取1個(gè)點(diǎn),稱量500 mm′500 mm′100 mm(長(zhǎng)′寬′高)耕層內(nèi)邊長(zhǎng)小于4 cm土塊質(zhì)量和土壤總質(zhì)量,兩者的比值則為該測(cè)試點(diǎn)的碎土率。為研究籠狀碎土輥的碎土效果,拆除機(jī)具尾部的籠狀碎土輥,以安裝普通齒狀碎土輥?zhàn)鳛閷?duì)照,分析了籠狀碎土棍的碎土效果。結(jié)果見(jiàn)表9,加裝籠狀碎土輥碎土率為84.18%,而加裝普通齒狀碎土輥碎土率為71.41%,結(jié)果表明,籠狀碎土輥可有效提高土壤的破碎效果,碎土率提高了12.77個(gè)百分點(diǎn);同時(shí)籠狀碎土輥在整個(gè)試驗(yàn)過(guò)程中沒(méi)出現(xiàn)土壤粘附和擁堵現(xiàn)象,表明籠狀碎土輥滿足設(shè)計(jì)要求。
表9 碎土率
1)為實(shí)現(xiàn)深松和旋耕2種耕作模式結(jié)合,降低深松阻力和提高碎土質(zhì)量,設(shè)計(jì)一種深松、旋耕、碎土聯(lián)合整地作業(yè)機(jī)。并對(duì)深松和碎土2大部件進(jìn)行了優(yōu)化設(shè)計(jì),設(shè)計(jì)了入土角可控的自激振動(dòng)深松鏟和具有二次碎土功能的籠狀碎土輥。
2)對(duì)自激振動(dòng)深松鏟進(jìn)行了土槽試驗(yàn),試驗(yàn)結(jié)果表明:自激振明自激振動(dòng)深松鏟減阻效果明顯,平均減阻9.22%;土壤蓬松度為26.16%,土壤擾動(dòng)系數(shù)為77.21%,性能較好。
3)對(duì)深松旋耕碎土聯(lián)合整地機(jī)進(jìn)行了田間試驗(yàn),試驗(yàn)結(jié)果表明:作業(yè)能有效的改善土壤的耕層結(jié)構(gòu),降低土壤容重;深松深度穩(wěn)定系數(shù)為94.92%,整地深度穩(wěn)定系數(shù)為92.50%,地表平整度為1.17 cm,植被覆蓋率為93.36%;加裝普通齒狀碎土輥的碎土率為71.41%,而加裝籠狀碎土輥機(jī)具的碎土率為84.18%,表明籠狀碎土輥可有效提高土壤的破碎效果;綜上,整機(jī)的各項(xiàng)參數(shù)均滿足作業(yè)質(zhì)量標(biāo)準(zhǔn)要求。
本文對(duì)深松旋耕整地機(jī)的深松部件和碎土部件進(jìn)行了相應(yīng)設(shè)計(jì),并通過(guò)試驗(yàn)分析了深松部件的減阻效果和碎土部件的碎土效果及整機(jī)作業(yè)性能。因現(xiàn)有的深松旋耕整地機(jī)種類繁多,同一機(jī)具在不同工況條件下的作業(yè)性能參數(shù)可能不同,故該文未做對(duì)比研究,后續(xù)可根據(jù)實(shí)際情況進(jìn)一步同其他類型的深松旋耕聯(lián)合作業(yè)機(jī)械在相同工況條件下進(jìn)行作業(yè)性能對(duì)比探討。
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Design and test of soil preparation machine combined subsoiling, rotary tillage and soil breaking
Zhao Jianguo, Wang An, Ma Yuejin, Li Jianchang, Hao Jianjun, Nie Qingliang, Long Sifang, Yang Qiangfeng
(071001,)
In order to reduce tillage resistance, ameliorate the soil layer structure and improve soil breaking rate of soil crushing roller, a combined tillage machine which has function of subsoiling, rotary tillage and soil breaking was designed in this paper. The machine mainly consists of a fixed mount to connect the subsoiler, rotary and soil crushing roller with the machine frame, the self-excited vibration subsoiler breaks the bottom of theplow pan, the rotary tiller flattens the soil and further shreds the soil, the soil crushing roller further breaks the soil thus creating a seedbed suitable for plant growth. 2 major components of machine are optimized to solve the problem of large tillage resistance and poor soil breaking effect. Firstly, the self-excited vibration subsoiler with controllable penetration angle was designed, which can avoid the problem of poor drag reduction effect and stability of tillage depth when the penetration angle of subsoiler is too large. The subsoiler produces a vibration to loosen the soil to achieve the purpose of drag reduction because of resistance changes in soil operation. In addition, the penetration angle of subsoiler is controlled to a range to maintain the stability of subsoiling depth. To ensure the compression spring can not be tilted during the subsoiling operation, and considering the problem of large load and limited installation space, the combination spring is selected as the self-excited vibration spring. Through the kinematics and mechanical model of self-excited vibration subsoiler, the deflection is 15 mm and the minimum and maximum loads are 7 500 and 15 000 N respectively, then the parameters of the combined spring was determined.Secondly, in order to realize the secondary soil-broken function, a caged soil crushing roller was designed by staggered welding of rhombic soil-broken teeth on a cylindrical drum with clearance. The soil is first broken by the outside teeth of soil-brokentooth, and the large soil will enter the cylindrical drum inside through the gap and will broken under the action of inside teeth, which can’t adhere to the cylindrical drum. The caged soil crushing roller diameter and thickness of soil-broken teeth is calculated according to the design formula of the disc harrow. To study the drag reduction effect and tillage quality of self-excited vibration subsoiler, the experiment in the soil bin is carried out, and the field experiment of operation performance of the machine is carried out. The soil bin experiment results showed that the self-excited vibration subsoiler has obvious effect on drag reduction, and the average drag reduction is 9.22%, and the soil fluffy degree and disturbance coefficient is 26.16% and 77.21% respectively. The field experiment results showed that the stability coefficient of subsoiling depth, stability coefficient of depth of soil preparation, surface flatness, vegetation coverage and soil breaking rate is 94.92%, 92.50%, 1.17cm, 93.36% and 84.18% respectively. The soil breaking rate of ordinary soil crushing roller is 71.41%, which indicates that the caged soil crushing roller can effectively improve the soil breaking effect. Moreover, the caged soil crushing roller did not appear soil adhesion and congestion during the test. All parameters meet the requirements of the work quality standards. Therefore, the machine has obvious effect of reducing resistance and quality of the soil preparation.This study can provide a theoretical reference for further research of combined tillage machine of subsoiling and rotary.
agricultural machinery; design; subsoiling; rotary tillage; caged soil crushing roller; self-excited vibration
2019-01-10
2019-03-07
國(guó)家“十三五”科技支撐重大項(xiàng)目糧食豐產(chǎn)增效科技創(chuàng)新(2017YFD0300907)
趙建國(guó),副教授,博士,主要從事耕整地機(jī)械裝備設(shè)計(jì)及農(nóng)機(jī)部件延壽方面的研究。Email:zjg790710@126.com
10.11975/j.issn.1002-6819.2019.08.006
S222.4
A
1002-6819(2019)-08-0046-09
趙建國(guó),王 安,馬躍進(jìn),李建昌,郝建軍,聶慶亮,龍思放,楊前鋒. 深松旋耕碎土聯(lián)合整地機(jī)設(shè)計(jì)與試驗(yàn)[J]. 農(nóng)業(yè)工程學(xué)報(bào),2019,35(8):46-54. doi:10.11975/j.issn.1002-6819.2019.08.006 http://www.tcsae.org
Zhao Jianguo, Wang An, Ma Yuejin, Li Jianchang, Hao Jianjun, Nie Qingliang, Long Sifang, Yang Qiangfeng. Design and test of soil preparation machine combined subsoiling, rotary tillage and soil breaking[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(8): 46-54. (in Chinese with English abstract) doi:10.11975/j.issn.1002-6819.2019.08.006 http://www.tcsae.org