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1MCDS-100A型鏟篩式殘膜回收機(jī)的設(shè)計與試驗(yàn)

2017-06-27 01:31:07游兆延胡志超吳惠昌張亞萍顏建春周新星
農(nóng)業(yè)工程學(xué)報 2017年9期
關(guān)鍵詞:篩面回收機(jī)殘膜

游兆延,胡志超,吳惠昌,張亞萍,顏建春,嚴(yán) 偉,周新星

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1MCDS-100A型鏟篩式殘膜回收機(jī)的設(shè)計與試驗(yàn)

游兆延,胡志超※,吳惠昌,張亞萍,顏建春,嚴(yán) 偉,周新星

(農(nóng)業(yè)部南京農(nóng)業(yè)機(jī)械化研究所,南京 210014)

為了減少鏟篩式殘膜回收機(jī)在工作中的振動,設(shè)計了雙篩面呈上下平行排布的減振式自平衡殘膜回收機(jī),確定偏心輪旋轉(zhuǎn)軸轉(zhuǎn)速范圍為260~330 r/min,采用DH5902動態(tài)測試系統(tǒng)對雙篩面殘膜回收機(jī)的振動參數(shù)進(jìn)行了田間作業(yè)測試,試驗(yàn)結(jié)果表明振動頻率在3~5.5 Hz變化時,機(jī)架左右方向振動測量值范圍在4.2~5.4 m/s2,在設(shè)備可承受振動范圍內(nèi),雙篩面減振效果明顯。通過單因素試驗(yàn)確定篩面形式為鋸齒篩,另外,設(shè)計了電動推桿式自動卸膜裝置,耗時4.1 s完成卸膜任務(wù)。選取機(jī)具前進(jìn)速度、逐膜篩振動頻率、逐膜篩振幅、鋸齒間距作為試驗(yàn)因素,運(yùn)用響應(yīng)曲面法并在Matlab2013a軟件中繪制四維切片圖來分析各因素對殘膜回收指標(biāo)的影響效應(yīng),結(jié)果表明試驗(yàn)因素對殘膜回收質(zhì)量有較大影響,綜合優(yōu)化結(jié)果為機(jī)具前進(jìn)速度0.73 m/s,逐膜篩振幅99 mm,逐膜篩振動頻率為280 r/min,篩面鋸齒間距12 mm,此時殘膜回收率為91.26%,纏膜率為4.27 %,膜土比為2.16。該研究不僅為農(nóng)機(jī)市場提供了一種實(shí)用機(jī)具,也為殘膜回收機(jī)械創(chuàng)新研發(fā)和優(yōu)化提升提供了理論依據(jù)和參考借鑒。

農(nóng)業(yè)機(jī)械;設(shè)計;振動控制;雙篩面;驅(qū)振裝置;膜土分離;殘膜回收機(jī)

0 引 言

沙土或沙壤土是中國主要土壤類型之一,主要分布在黃河故道沙土區(qū)、沿海平原沙土區(qū)等區(qū)域[1],各區(qū)因地制宜,為保溫保墑[2],適宜于沙土的花生、棉花、馬鈴薯等作物常采用覆膜種植,收獲后大量殘膜污染農(nóng)田造成嚴(yán)重的白色污染[3-6]。以華北地區(qū)為例,相比于玉米、蔬菜等其他土壤種植作物,花生和棉花的平均地膜殘留強(qiáng)度最高,預(yù)計到2021年,花生地和棉田的地膜殘留強(qiáng)度將分別達(dá)到69.1和70.4 kg/hm2,中國2010年制定了《農(nóng)田地膜殘留量限值及測定》標(biāo)準(zhǔn),采用65 kg/hm2作為0~20 cm 土層的地膜殘留量限值,如果不注重殘膜回收工作,這些地區(qū)將成為殘膜污染區(qū)域[7-8]。

由于沙土或沙壤土有較好的易碎性,在機(jī)械化回收農(nóng)作物及殘留地膜時,國內(nèi)外多家單位對鏟篩式挖掘收獲機(jī)做了大量研究,意大利Checchi&Magli公司研制的SP100振動篩式馬鈴薯收獲機(jī),通過2個左右等水平排列的篩面在高頻驅(qū)動下低幅抖動,物料在篩面上需改變運(yùn)動方向,僅適合塊狀類作物的回收;南京農(nóng)機(jī)化所和開封茂盛機(jī)械有限公司聯(lián)合研制的4H-800型振動篩式花生收獲機(jī),該機(jī)采用單層篩床配振動偏心輪結(jié)構(gòu),偏心塊的回轉(zhuǎn)運(yùn)動無法消除篩床的往復(fù)運(yùn)動,機(jī)具作業(yè)過程中振動大,機(jī)手作業(yè)強(qiáng)度大[9-11];甘肅洮河拖拉機(jī)有限公司研制的4U-400型鏟篩式馬鈴薯挖掘機(jī),偏心輪推動主篩擺桿及副篩擺桿往復(fù)運(yùn)動,帶動挖掘鏟,主、副篩柵條產(chǎn)生高頻低幅往復(fù)運(yùn)動,但主副篩柵條運(yùn)動方向相同,作業(yè)過程中振動偏大,整機(jī)作業(yè)效率較低[12];山西長治永成三輪車廠生產(chǎn)的4S-80型馬鈴薯振動挖掘機(jī),采用鏟篩一體的振動結(jié)構(gòu),鏟篩振動狀態(tài)下可顯著降低牽引阻力,但拖拉機(jī)也發(fā)生強(qiáng)烈振動,極易引發(fā)機(jī)具的損壞和駕駛員身體損傷[13];山東大學(xué)機(jī)械工程學(xué)院設(shè)計了擺動式挖掘收獲機(jī),將挖掘機(jī)構(gòu)與篩選機(jī)構(gòu)合二為一,并從縱向分為兩部分,采用反平行四邊形原理,使兩部分等角度、反方向擺動,但整機(jī)功率較大,振動篩頻率較慢。目前國內(nèi)外鮮有鏟篩式殘膜回收機(jī)報道,究其原因是現(xiàn)有驅(qū)振方式大多無法很好解決振動平衡問題,另外篩面在篩分過程中無擋下滑設(shè)計,加上膜、土、雜等自身重力因素,造成土塊堆積、篩孔堵塞,膜土分離效率低,殘膜回收質(zhì)量不高。

針對殘膜回收機(jī)的作業(yè)特點(diǎn),結(jié)合地膜回收農(nóng)藝要求,本文設(shè)計了一種雙篩體自平衡減振式殘膜回收機(jī),可一次性完成起膜、膜土分離、集膜、卸膜,作業(yè)可靠,具有良好的推廣應(yīng)用前景。

1 鏟篩式殘膜回收機(jī)總體結(jié)構(gòu)及工作原理

1MCDS-100A型鏟篩式殘膜回收機(jī)結(jié)構(gòu)圖如圖1所示,主要由以下幾部分組成:機(jī)架、驅(qū)振裝置、前篩、后篩、限深裝置和集膜筐。

鏟篩式殘膜回收機(jī)收獲時,挖掘鏟組件挖掘膜土,膜土混合物落到前篩,在驅(qū)振裝置作用下,前篩面在松破土的同時逐級將剩余的土和殘膜繼續(xù)往后篩輸送,落到后篩的膜土混合物繼續(xù)在后篩的篩程內(nèi)完成膜土分離和輸膜任務(wù),最后將分離干凈的殘膜回收至集膜筐。

2 關(guān)鍵部件參數(shù)設(shè)計

2.1 驅(qū)振系統(tǒng)平衡設(shè)計

驅(qū)振裝置主要由變速箱、驅(qū)振軸、飛輪、偏心驅(qū)振臂組件、連桿組裝等組成。振動平衡問題是本機(jī)的核心,驅(qū)振系統(tǒng)振動平衡設(shè)計如圖2所示,包括兩方面,一是回轉(zhuǎn)運(yùn)動振動平衡設(shè)計,通過飛輪的回轉(zhuǎn)運(yùn)動來抵消偏心驅(qū)振臂(圖2a)的旋轉(zhuǎn),需配重軸承套、驅(qū)振臂板端蓋、軸承、偏心套(按無中間通孔計質(zhì)量)等合計總質(zhì)量為2.67 kg,配重慣距為0.024 kg·m,設(shè)計的飛輪結(jié)構(gòu)如下圖2b,二是雙篩面往復(fù)運(yùn)動振動平衡,設(shè)計反配置等慣量自平衡雙篩面(圖2c),雙篩面上下平行排布,且前篩床的后端和后篩床的前端上下重疊,前篩和后篩始終保持同時反向運(yùn)動。

2.2 雙篩面振動篩運(yùn)動參數(shù)確定

雙篩面振動篩機(jī)構(gòu)運(yùn)動簡圖如圖3所示。偏心套圓心點(diǎn)繞驅(qū)振軸軸心點(diǎn)轉(zhuǎn)動,從而帶動連桿推動搖桿和,前篩面繞著鉸接點(diǎn)2來回擺動,后篩面繞著鉸接點(diǎn)4來回擺動,實(shí)現(xiàn)前后篩的同時反向往復(fù)振動,完成篩分任務(wù)。

1.變速箱組件 2.前篩框驅(qū)振臂組件 3.連桿組件 4.前篩 5.后篩框驅(qū)振臂組件 6.后篩 7.偏心驅(qū)振臂組件 8.張緊輪組件 9.支撐輪組件

1.Gearbox components 2.Drive arm components of forward screen frame 3.Connecting rod components 4.Front sieve 5.Drive arm components of back screen frame 6.Back sieve 7.Eccentric drive arm components 8.Tension pulley components 9.Supporting wheel components

c. 雙篩面往復(fù)運(yùn)動振動平衡設(shè)計

c. Vibration balance design for reciprocating motion of double-sieve

圖2 驅(qū)振系統(tǒng)振動平衡設(shè)計

Fig.2 Vibration balance design of drive system

前期樣機(jī)表明,偏心套偏心距=9~30 mm,=120~145 mm,=405 mm,=240 mm,=398 mm。為了膜土在篩面上完成一級或多級輸送的同時,也能夠松、破土,膜土分離效果好應(yīng)滿足如下條件[14-15]

前滑(1)

后滑(2)

拋離(3)

式中為篩軸角速度,rad/s;為擺動篩偏心套的旋轉(zhuǎn)半徑,mm;為膜土混合物與篩面的摩擦角,經(jīng)試驗(yàn)測得摩擦角為20.75°;為質(zhì)心加速度方向與軸所夾的銳角,43°;為篩面傾角,14°;為重力加速度,g/m2。

代入公式(1)、(2)和(3)得:雙篩的質(zhì)心加速度a范圍為:5.3 m/s2<a<17.3m/s2。

通過矢量方程圖解法對雙篩面振動機(jī)構(gòu)進(jìn)行篩面質(zhì)心加速度分析,進(jìn)而求出曲柄轉(zhuǎn)速的變化范圍。

(5)

式中為繞點(diǎn)的角速度,rad/s;為桿的轉(zhuǎn)速,r/min;w為桿的角速度,rad/s;l為桿的長度,m;l為點(diǎn)到和交點(diǎn)的長度,m。

式中為點(diǎn)線速度,m/s;為繞點(diǎn)的角速度,rad/s;l為點(diǎn)到和交點(diǎn)的距離,m;l為桿長度,m。

(7)

式中為點(diǎn)的線速度,m/s;為桿的角速度,rad/s;l為桿的長度,m;l為點(diǎn)到和交點(diǎn)的距離,m。根據(jù)同一構(gòu)件上相對加速度原理,桿上相對加速度示意圖如圖4所示。

可知桿的矢量方程為

矢量方程(8)在桿上投影為

(9)

(11)

(12)

式中為與過點(diǎn)的垂線之間的夾角,(°);為和的夾角,(°);l為桿的長度,m。

同理可得桿的矢量方程為:

式(13)在軸投影:

(14)

聯(lián)立式(4)-式(14)得:為滿足膜土混合物實(shí)現(xiàn)有效分離與輸送任務(wù)[16],偏心套轉(zhuǎn)速范圍:260 r/min <<330 r/min,變速箱輸出軸與殘膜回收機(jī)驅(qū)振軸的鏈傳動比在1.21~1.53之間。

2.3 逐膜篩面設(shè)計

據(jù)前期樣機(jī)研究,機(jī)具前進(jìn)速度為黃海金馬-254低速Ⅱ檔[17],逐膜篩振動頻率260 次/min,偏心套偏心距為9 mm,分別更換桿條篩、橫桿篩、編織篩、圓孔篩、鋸齒篩等5種不同結(jié)構(gòu)篩面形式進(jìn)行單因素試驗(yàn)[18],分析不同篩面對殘膜回收質(zhì)量的影響,經(jīng)比較,鋸齒篩的殘膜回收效果最好。由于鋸齒條具有單向輸送性,且膜沒有拋送速度,膜、土在篩面上的運(yùn)動軌跡如圖5所示,振動篩從圖中位置1運(yùn)動到2,試驗(yàn)過程中,剛開始土攜帶著膜一起運(yùn)動,當(dāng)驅(qū)振軸轉(zhuǎn)速低于260 r/min時,會有堵住篩孔的現(xiàn)象,膜土分離不徹底,當(dāng)高于260 r/min時,膜土運(yùn)動到前篩尾部時,大部分土就已經(jīng)分離出去了,膜土分離較徹底,沒有堵住篩孔的現(xiàn)象,到了后面只有膜在篩面上運(yùn)動。殘膜在篩面上依靠振動篩振幅的水平分量x往后輸送,為滿足膜土分離與輸送任務(wù),每一個振幅周期內(nèi),振動篩振幅的水平分量A應(yīng)大于一個鋸齒的寬度,振動篩振幅的垂直分量A應(yīng)大于一個鋸齒的高度,本文中振動篩最小的振幅為62 mm,為保證了振動篩有效逐級輸送殘膜,設(shè)計鋸齒條齒寬18 mm,齒高5 mm,鋸齒條厚度1.5 mm,齒條長度為573 mm。

2.4 電動推桿式自動卸膜裝置

實(shí)現(xiàn)自動卸膜是研制殘膜回收機(jī)的關(guān)鍵[19-20],圖6所示為設(shè)計的電動推桿式自動卸膜裝置。集膜筐質(zhì)量為16 kg,主體是一塊1.5 mm厚的鋼板經(jīng)幾道折彎加工,中間沖了很多20 mm的孔,質(zhì)量輕且整體剛度夠強(qiáng)。按照鋪0.01 mm膜,幅寬1 m,聚乙烯地膜的密度在950 kg/m3左右,即使全部覆膜,每畝地鋪膜質(zhì)量大概為6.33 kg,因本機(jī)主要適收沙土或沙壤土作物,鋸齒篩具有松破土和逐級輸送功能,最后到集膜筐里都是相對干凈的碎膜和長膜,膜裝滿集膜筐加起來不到10 kg。考慮到會有一些土塊或石子無法被鋸齒篩松破從而進(jìn)入集膜筐,故設(shè)定最大回收質(zhì)量為30 kg。

經(jīng)計算,空載時,集膜筐旋轉(zhuǎn)力臂192 mm,推桿拉力力臂57 mm,推桿啟動拉力應(yīng)不小于2 100 N,電動推桿選購北京中電宏立機(jī)電科技有限公司生產(chǎn)的型號:HLZ40-1-20-194-LT-IP65B,額定電壓12 V,最大推力2 500 N,行程194 mm,滿載速度47 mm/s,集膜筐在電動推桿活塞的作用下,繞著集膜筐回轉(zhuǎn)套4.1 s內(nèi)就能實(shí)現(xiàn)集膜筐的卸膜和歸位,解決了卸膜環(huán)節(jié)人工費(fèi)時費(fèi)力、需停機(jī)卸膜等問題。

3 雙篩面殘膜回收機(jī)抗振特性測試

為驗(yàn)證振動平衡的設(shè)計,以江蘇東華測試有限公司生產(chǎn)的DH5902動態(tài)測試分析系統(tǒng)和DHDAS分析軟件為載體,DH5902測試系統(tǒng)有16個通道,最高采樣速率256 kHz/通道;采用USB3.0與儀器通訊,實(shí)時傳送采樣數(shù)據(jù);每通道獨(dú)立的24bitA/D轉(zhuǎn)換器。加速度傳感器采用DH131E壓電式加速度傳感器(頻率測量范圍為1~10 kHz),靈敏度單位是0.1 (mV/pC),利用時域和頻域信號分析方法,選取驅(qū)動軸轉(zhuǎn)速由3 Hz增加到5.5 Hz(每次增加0.5 Hz),在1MCDS-100A鏟篩式殘膜回收機(jī)的3個測點(diǎn)位置駕駛室、機(jī)架和集膜筐處分別安裝傳感器,對各測點(diǎn)左右、前后、上下,3個方向的振動信號分別在空載和田間作業(yè)狀態(tài)下進(jìn)行測試[21-22],如圖7所示。

經(jīng)測量,前輪樣機(jī)配置方式為單層篩床配有扇形偏心塊,空載時機(jī)架、駕駛室、集膜筐處水平方向振動平均值超過16.4 m/s2。對殘膜回收機(jī)進(jìn)行測量,測量值如表1,測定結(jié)果表明,隨著振動頻率的增大,加速度總體呈增大趨勢,對各測點(diǎn)位置加速度進(jìn)行合成,滿載作業(yè)相對于空載時,駕駛室振動強(qiáng)度總體降低了10%~23%,機(jī)架振動強(qiáng)度總體降低了8.7%~19.1%,集膜筐振動強(qiáng)度降低了12.4%~23.5%,各振動位置測量值均在機(jī)器可承受振動范圍內(nèi),減振效果明顯[23-24]。

a. 振動分析儀及處理軟件a. Vibration analyzer and processorb. 機(jī)架測試方位坐標(biāo)示意圖b. Schematic diagram of test orientation for frame c. 田間振動測試c. Field vibration test

表1 各位置不同頻率、不同作業(yè)狀態(tài)下振動加速度測量

4 試驗(yàn)分析

試驗(yàn)地點(diǎn)選在山東膠州北王珠鎮(zhèn)大趙家村。試驗(yàn)地為典型沙壤土土質(zhì),壟作馬鈴薯大壟雙行種植模式,機(jī)具配套動力18~30 kW,挖掘深度設(shè)計為80~200 mm可調(diào),作業(yè)幅寬1 m,生產(chǎn)效率為0.3~0.4 hm2/h,試驗(yàn)地長300 m,寬50 m,壟高11 cm,覆膜寬度為1 m,覆膜厚度為0.008 mm,土壤含水率為8.34%,地膜殘留量為185 kg/hm2,殘膜試樣寬度為15 mm,試驗(yàn)速度為500 mm/min時,殘膜受到的拉力峰值為1.2 N,拉伸強(qiáng)度為8 MPa(由深圳三思萬能試驗(yàn)機(jī)測得,選用電動楔形拉伸夾具,型號為JXSA304B)。

4.1試驗(yàn)指標(biāo)與因素

試驗(yàn)分別將殘膜回收率、纏膜率[25]和膜土比[26]作為殘膜回收機(jī)作業(yè)指標(biāo),試驗(yàn)指標(biāo)計算方法如下:

1)殘膜回收率

式中為殘膜回收率,%;1為測區(qū)內(nèi)漏在地里未回收膜的質(zhì)量,g;2為測區(qū)內(nèi)纏在篩面上膜的質(zhì)量,g;3為測區(qū)內(nèi)回收到集膜筐中膜的質(zhì)量,g。

2)纏膜率

式中為纏膜率,%。

3)膜雜分離是殘膜回收的難點(diǎn),因?yàn)榻斩捲谕寥乐袝环纸?,所以將秸稈?dāng)作土處理計算,在集膜筐下方放置一塊大的彩條布,稱下總質(zhì)量,再將膜上的土盡可能抖干凈,再稱膜質(zhì)量。

式中為膜土比;為集膜筐中膜土總質(zhì)量,g。膜土比≥1時,收上的膜比較干凈。通過對殘膜回收機(jī)回收機(jī)理的分析,根據(jù)其結(jié)構(gòu)特點(diǎn),確定影響殘膜回收率、纏膜率、膜土比的主要因素為:逐膜篩振幅,逐膜篩振動頻率,鋸齒間距和機(jī)具前進(jìn)速度。

4.2 試驗(yàn)設(shè)計與方法

在膜土分離和輸膜過程中,存在很多影響收膜率和膜土比的非線性因素,常需要選用二次或更高次的模型來逼近響應(yīng),模型可采用Box-Benhnken中心組合設(shè)計理論來建立[27]。以殘膜回收率1、纏膜率2、膜土比3作為響應(yīng)值,對逐膜篩振幅,逐膜篩振動頻率,鋸齒間距和機(jī)具前進(jìn)速度等因素開展響應(yīng)面試驗(yàn)研究。利用4因素2次回歸試驗(yàn)設(shè)計方案,對影響殘膜回收率、纏膜率、膜土比的4個主要參數(shù)組合完成優(yōu)化。其中逐膜篩振幅指篩在振動過程中偏離初始位置的最大值,篩面振動頻率指篩面在每分鐘振動的次數(shù),鋸齒間距是指相鄰2個鋸齒條中心之間的距離。試驗(yàn)因素及水平設(shè)計見表2。

表2 響應(yīng)面試驗(yàn)因素和水平

逐膜篩頻率通過更換鏈輪來改變;更換不同偏心距的偏心套來改變逐膜篩的振幅[28];改變鋸齒間距可通過更換可拆卸的焊有不同間距的篩面獲取,拖拉機(jī)選用黃海金馬-254,通過使用低速Ⅱ檔、低速Ⅳ和高速Ⅰ檔來改變機(jī)具前進(jìn)速度。

4.3 模型建立與顯著性檢驗(yàn)

應(yīng)用Design-Expert.V8.0.6.1軟件進(jìn)行試驗(yàn)設(shè)計、數(shù)據(jù)處理與統(tǒng)計分析,根據(jù)Box-Benhnken設(shè)計方法進(jìn)行4因素3水平響應(yīng)面試驗(yàn),選擇29個點(diǎn),包括24個分析因子和5個零點(diǎn)估計誤差,試驗(yàn)設(shè)計及響應(yīng)結(jié)果如表3所示,并對試驗(yàn)結(jié)果進(jìn)行方差分析(表3)。

表3 試驗(yàn)設(shè)計方案及響應(yīng)值結(jié)果

注:1為殘膜回收率;2為纏膜率;3為膜土比。

Note:1is the recovery rate of residual film, %;2is the rate of winded film, %;3is the film soil ratio.

針對表3的樣本數(shù)據(jù),建立回歸模型,如方程所示

由表4數(shù)據(jù)分析可知,殘膜回收率1、纏膜率2、膜土比3的響應(yīng)面模型的<0.0001,回歸方程中各變量對指標(biāo)影響的顯著性由檢驗(yàn)判定,概率值越小則相應(yīng)變量的顯著性越高[29]。從各因素值可以看出,鋸齒間距、機(jī)具前進(jìn)速度對殘膜回收率有顯著影響,各因素影響強(qiáng)弱次序?yàn)椋轰忼X間距>機(jī)具前進(jìn)速度>逐膜篩振幅>逐膜篩振動頻率。機(jī)具前進(jìn)速度,鋸齒間距對纏膜率有顯著影響,且影響強(qiáng)弱次序?yàn)椋轰忼X間距>機(jī)具前進(jìn)速度>逐膜篩振幅>逐膜篩振動頻率。機(jī)具前進(jìn)速度,逐膜篩振動頻率,逐膜篩振幅,鋸齒間距對膜土比有顯著影響,且影響強(qiáng)弱次序?yàn)椋轰忼X間距>機(jī)具前進(jìn)速度>逐膜篩振動頻率>逐膜篩振幅。殘膜回收率、纏膜率和膜土比各模型的決定系數(shù)分別為0.9575、0.9674和0.9541,說明該模型誤差較小,可以用此模型對鏟篩式殘膜回收機(jī)的殘膜回收率、纏膜率和膜土比進(jìn)行分析和預(yù)測。

表4 回歸模型方差分析

4.4 因素影響效應(yīng)分析

依據(jù)建立的各指標(biāo)的優(yōu)化回歸模型,按照因素重要性和顯著性順序,分別選取對各指標(biāo)影響最為重要的3個因素,用Matlab2013a軟件繪制四維切片圖來直觀描述各因素對殘膜回收指標(biāo)的影響效應(yīng)[30-31]。

機(jī)具前進(jìn)速度、逐膜篩振動頻率、鋸齒間距3個因素與殘膜回收率影響效應(yīng)如圖8a所示,總體影響趨勢為:機(jī)具前進(jìn)速度越快、鋸齒間距越大,殘膜回收率越低。原因分析:當(dāng)機(jī)具前進(jìn)速度增加時,單位時間內(nèi)的膜土喂入量增多,工作負(fù)荷加大,殘膜回收率降低;當(dāng)鋸齒間距增加時,一些碎膜從鋸齒間掉落到田塊中,導(dǎo)致殘膜回收率降低。

機(jī)具前進(jìn)速度、逐膜篩振幅、鋸齒間距3個因素與纏膜率影響效應(yīng)如圖8b所示,總體影響趨勢為:機(jī)具前進(jìn)速度越快、逐膜篩振幅越小、鋸齒間距越小,則纏膜率越高,反之則纏膜率低。原因分析:機(jī)具前進(jìn)速度越快,喂入量增加,篩床抖動膜土?xí)r,先進(jìn)入篩面的膜土未完全分離又有新的膜土涌入篩床,造成輸膜性能下降,纏膜率隨機(jī)具前進(jìn)速度的增加而升高,篩體間距減小時,單位面積的鋸齒面積增加,纏膜的幾率增加,纏膜率越高;另外,隨著逐膜篩振幅的減小,殘膜通過篩程內(nèi)的時間增長,被篩面纏住的可能性也就越大,纏膜率也就越高。

鋸齒間距、機(jī)具前進(jìn)速度、逐膜篩振動頻率3個因素與膜土比影響效應(yīng)如圖8c所示,總體影響趨勢為:鋸齒間距越小,機(jī)具前進(jìn)速度越快,逐膜篩振動頻率越低,則膜土比越低,反之膜土比越高。原因分析:鋸齒間距較小時,大部分的土無法從鋸齒間隙中落入地表,進(jìn)入篩面的土量變多,篩分效率低,膜土比??;機(jī)具前進(jìn)速度越快,喂入量增大,多余的膜土還來不及被篩面分離就被往后輸送,導(dǎo)致膜土分離不徹底,膜土比低;逐膜篩振動頻率越快,膜土混合物單位時間內(nèi)在篩面上抖動的次數(shù)越多,膜土分散的越均勻,膜土分離效果越好,膜土比越高。

4.5 參數(shù)優(yōu)化與驗(yàn)證

4.5.1 參數(shù)優(yōu)化

本文按照殘膜回收率最高、纏膜率最低、膜土比最大的殘膜回收要求為優(yōu)化目標(biāo),開展鏟篩式殘膜回收機(jī)各參數(shù)優(yōu)化研究。運(yùn)用Design-Expert 數(shù)據(jù)分析軟件對建立的3 個指標(biāo)的全因子二次回歸模型最優(yōu)化求解,約束條件為:1)目標(biāo)函數(shù):max1;min2;max3;2)變量區(qū)間:0.73≤1≤2.23,260≤2≤330,62≤3≤113,12≤4≤36。優(yōu)化后得到的各因素最優(yōu)參數(shù)為:機(jī)具前進(jìn)速度為0.73 m/s,振動篩頻率為280.63 r/min,逐膜篩振幅為99.63 mm,篩面鋸齒間距12 mm。此時模型預(yù)測的殘膜回收率為91.59%,纏膜率為4.15 %,膜土比為2.59。

4.5.2 試驗(yàn)驗(yàn)證

響應(yīng)面試驗(yàn)中并未包括上述優(yōu)化后的最優(yōu)參數(shù)組合方案,為了驗(yàn)證響應(yīng)面模型和優(yōu)化結(jié)果的可靠性,采用上述最佳參數(shù)組合??紤]試驗(yàn)操作的可行性,在機(jī)構(gòu)設(shè)計時將參數(shù)最佳條件修正為機(jī)具前進(jìn)速度為0.73 m/s,振動篩頻率為280 r/min,逐膜篩振幅為99 mm,篩面鋸齒間距12 mm,在殘膜回收機(jī)上進(jìn)行 3 次重復(fù)驗(yàn)證試驗(yàn),取平均值為試驗(yàn)驗(yàn)證值,試驗(yàn)結(jié)果分別為殘膜回收率91.26%,纏膜率為4.27%,膜土比為2.16。對比分析可知,1、2、3 的理論優(yōu)化值和試驗(yàn)值很接近,因此,上述預(yù)測模型是可靠的,得到的最優(yōu)結(jié)構(gòu)參數(shù)是符合要求的。

5 結(jié) 論

1)設(shè)計呈上下平行排布的雙篩面減振式自平衡殘膜回收機(jī),確定了驅(qū)振系統(tǒng)振動平衡中的關(guān)鍵運(yùn)動參數(shù),利用DH5902動態(tài)測試分析系統(tǒng)和DHDAS分析軟件,得到振動頻率在3~5.5 Hz變化時,機(jī)架左右方向振動測量值范圍在4.2~5.4 m/s2,驗(yàn)證了整機(jī)減振效果明顯。

2)單因素試驗(yàn)確定篩面結(jié)構(gòu)為鋸齒篩,選取機(jī)具前進(jìn)速度、逐膜篩振幅、逐膜篩振動頻率和鋸齒間距作為試驗(yàn)因素,運(yùn)用Matlab軟件分析試驗(yàn)數(shù)據(jù),各因素影響殘膜回收率的主次順序?yàn)椋轰忼X間距>機(jī)具前進(jìn)速度>逐膜篩振幅>逐膜篩振動頻率;各因素影響纏膜率的強(qiáng)弱次序?yàn)椋轰忼X間距>機(jī)具前進(jìn)速度>逐膜篩振幅>逐膜篩振動頻率;各因素影響膜土比強(qiáng)弱次序?yàn)椋轰忼X間距>機(jī)具前進(jìn)速度>逐膜篩振動頻率>逐膜篩振幅。綜合優(yōu)化后的殘膜回收機(jī)各參數(shù)為:機(jī)具前進(jìn)速度0.73 m/s,逐膜篩振幅99 mm,逐膜篩振動頻率280 次/min,鋸齒間距12 mm,此時殘膜回收率91.26%,纏膜率為4.27 %,膜土比為2.16。

1MCDS-100A鏟篩式殘膜回收機(jī),可一次性完成起膜、膜土分離、集膜、自動卸膜等作業(yè)工序,對于種植花生、棉花、馬鈴薯等作物的沙土或沙壤土地中的殘留地膜回收具有良好的推廣應(yīng)用前景。

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Design and experiment of 1MCDS-100A typed shovel-sieve residual film recovery machine

You Zhaoyan, Hu Zhichao※, Wu Huichang, Zhang Yaping, Yan Jianchun, Yan Wei, Zhou Xinxing

(210014)

Plastic mulching planting pattern is usually adopted when planting peanut, cotton and other crops in modern agriculture, and the planting soil type is mostly in sandy soil or sandy loam with good fragility. As more and more residual membrane left in the field surface, accumulation of the residual film which is not clearly picked up all the year round, causing serious “white pollution”. Taking typical croplands in North China for example, it is estimated that, the quantity of residual film in peanut and cotton fields would reach up to 69.1 and 70.4 kg/hm2by 2021, If we do not pay attention to the recovery of residual film, these areas would become the pollution area contaminated by residual plastic membrane. In order to solve serious pollution of residual plastic film left in the field after harvest, several residual film recovery machines are commonly used, such as tooth type (spike tooth, elastic claw, telescopic tooth, etc.), curl-up film roller type, shovel-chain type, and multi-function duplex machinery, but both domestic and international shovel-sieve type residual film recovery machines which adapt to sandy soil have been rarely reported. First, the current sieving surface had no structural design of blocking glide in the process of screening, while film, soil and impurity substance could easily cause soil accumulation because of its own gravity, leading to the clogging of sieve holes with low membrane separation efficiency. Second, the step by step transmission ability of vibration sieve was poor, causing residual film winding, membrane leakage, reversing and other issues. In addition, most of the existing shovel-screen type residual film recycling machines had only one single sieve. As such cleanliness of recycled residual film needs to be improved. At the same time, in order to reduce vibration, the existing eccentric drive arm equipment was often equipped with rotary parts when screening, such as the eccentric block, flywheel or other parts, but rotary motion of chosen rotary parts could not eliminate the reciprocating movement of sieve, causing large vibration in the process of machine operation, high labor intensity of drivers and poor stability of machinery. In order to reduce vibration in the operation of shovel-sieve type residual film recycling machine, in this study, a up and down parallel arranged double-sieve type self-balancing residual film recycling machine was designed, rotation speed of drive shaft was determined, ranging from 260 to 330 r/min, a DH5902 dynamic testing system was used. A field experiment was carried out to test the vibration parameters of the double-sieve residual film recycling machine and the experimental results showed that vibration frequency from 3 to 5.5 Hz, horizon vibration measurement value of the frame was 4.2-5.4 m/s2, among which the equipment could withstand, the damping effect of double-sieve residual film recycling machine was obvious, five sieves with different sieve surface structures including the bar sieve, cross bar sieve, wire gauze sieve, round hole sieve and saw-tooth sieve were tested by single factor experiment. Finally, saw-tooth sieve was determined as the optimal sieve form. Moreover, an electric pushing rod typed automatic film uploading device was designed, film collecting basket completed the unloading task in 4.1 s, solving longtime labor issues currently exist in uploading link. Machine forward speed, vibration frequency of saw-tooth sieve, amplitude of saw-tooth sieve and saw-tooth distance were selected as experiment factors. The response surface method was used, and the effect of each factor influenced on the targets of the residual film recycling was analyzed by drawing four-dimensional chip figure on Matlab2013a software. The experimental results showed that the test factors had a great influence on residual film recovery quality. The optimal parameter combination was obtained: machine forward speed was 0.73 m/s, amplitude of saw-tooth sieve was 99 mm, vibration frequency of saw-tooth sieve was 280 r/min, saw-tooth distance was 12 mm, when the recovery rate of residual film was 91.26%, rate of winded film was 4.27% and film soil ratio was 2.16. It met the requirements of the residual film recycling quality. This study not only supplies the residual film recycling market with a both urgent and practical tool, but also provides theoretical basis and reference for the innovation development and optimization of plastic film recovery machinery.

agricultural machinery; design; vibration control; double sieve; drive mechanism; membrane-soil separation;residual film recycling machine

10.11975/j.issn.1002-6819.2017.09.002

S223.5

A

1002-6819(2017)-09-0010-09

2016-09-02

2017-04-11

公益性行業(yè)(農(nóng)業(yè))科技“殘膜污染農(nóng)田綜合治理技術(shù)方案”(201503105);中國農(nóng)科院創(chuàng)新工程—土下果實(shí)收獲機(jī)械

游兆延,男,江蘇泰興人,主要從事農(nóng)業(yè)機(jī)械化工程研究。南京農(nóng)業(yè)部南京農(nóng)業(yè)機(jī)械化研究所,210014。Email:17366350354@163.com

胡志超,男,陜西藍(lán)田人,研究員,主要從事農(nóng)作物收獲及產(chǎn)后加工技術(shù)裝備的研究。南京農(nóng)業(yè)部南京農(nóng)業(yè)機(jī)械化研究所,210014。Email:nfzhongzi@163.com,中國農(nóng)業(yè)工程學(xué)會高級會員:胡志超(E041200498S)

游兆延,胡志超,吳惠昌,張亞萍,顏建春,嚴(yán) 偉,周新星. 1MCDS-100A型鏟篩式殘膜回收機(jī)的設(shè)計與試驗(yàn)[J]. 農(nóng)業(yè)工程學(xué)報,2017,33(9):10-18. doi:10.11975/j.issn.1002-6819.2017.09.002 http://www.tcsae.org

You Zhaoyan, Hu Zhichao, Wu Huichang, Zhang Yaping, Yan Jianchun, Yan Wei, Zhou Xinxing. Design and experiment of 1MCDS-100A typed shovel-sieve residual film recovery machine[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(9): 10-18. (in Chinese with English abstract) doi:10.11975/j.issn.1002-6819.2017.09.002 http://www.tcsae.org

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