高志朋,徐立章,李耀明,王亞丁,孫朋朋
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履帶式稻麥聯(lián)合收獲機(jī)田間收獲工況下振動(dòng)測(cè)試與分析
高志朋,徐立章※,李耀明,王亞丁,孫朋朋
(江蘇大學(xué)現(xiàn)代農(nóng)業(yè)裝備與技術(shù)教育部重點(diǎn)實(shí)驗(yàn)室,鎮(zhèn)江 212013)
為研究履帶式全喂入聯(lián)合收獲機(jī)田間收獲時(shí)的振動(dòng)特性以及不同喂入量下的振動(dòng)特性,以沃得銳龍4LZ-5.0E履帶式全喂入稻麥聯(lián)合收獲機(jī)為研究對(duì)象,利用DH5902動(dòng)態(tài)信號(hào)測(cè)試分析系統(tǒng)對(duì)不同喂入量收獲工況下整機(jī)12個(gè)測(cè)點(diǎn)處的振動(dòng)進(jìn)行了測(cè)試與分析,結(jié)果表明振動(dòng)篩、脫粒滾筒、發(fā)動(dòng)機(jī)分別是機(jī)器前后、左右、上下方向上的主要激振源,但作物喂入割臺(tái)和輸送槽組成的腔體結(jié)構(gòu)后,吸收了部分振動(dòng),使得割臺(tái)和輸送槽測(cè)點(diǎn)處的振動(dòng)總量分別下降了25%、39%;與無(wú)作物喂入相比,喂入量為2.44 kg/s時(shí)輸送槽驅(qū)動(dòng)軸和脫粒滾筒測(cè)點(diǎn)處的振動(dòng)分別增大了90%和149%,而喂入量增大到3.87 kg/s時(shí)振動(dòng)總量卻下降了15%左右,因此收獲時(shí)應(yīng)使機(jī)器保持一定的喂入量,可以降低整機(jī)振動(dòng);駕駛座椅支座、發(fā)動(dòng)機(jī)機(jī)腳支座和底盤機(jī)架上測(cè)點(diǎn)處的振動(dòng)均與作物喂入量呈正相關(guān)性。研究結(jié)果可為降低履帶式聯(lián)合收獲機(jī)田間收獲工況下整機(jī)振動(dòng),進(jìn)而提高其駕駛舒適性提供參考。
聯(lián)合收獲機(jī);振動(dòng);噪聲;不同喂入量;田間收獲
稻麥聯(lián)合收獲機(jī)是一種在大田工作的農(nóng)業(yè)機(jī)械,為滿足潮濕、泥濘等惡劣地面環(huán)境下的持續(xù)工作要求,稻麥聯(lián)合收獲機(jī)一般采用橡膠履帶式行走底盤[1]。全喂入稻麥聯(lián)合收獲機(jī)田間收獲時(shí),一次作業(yè)要完成作物的切割、輸送、脫粒分離、清選等工作,往復(fù)和回轉(zhuǎn)部件多,激振源復(fù)雜[2]。此外,受經(jīng)濟(jì)條件和成本的限制,中國(guó)履帶式全喂入聯(lián)合收獲機(jī)除發(fā)動(dòng)機(jī)與底盤機(jī)架之間采用橡膠減振塊外,其他部件之間多為剛性連接,且機(jī)體主要是由型材、板材焊接形成框架、罩殼復(fù)合結(jié)構(gòu),使得聯(lián)合收獲機(jī)整機(jī)振動(dòng)較大,噪聲較高。聯(lián)合收獲機(jī)的振動(dòng)容易造成部件的疲勞損壞,發(fā)生故障,降低工作可靠性和無(wú)故障工作時(shí)間,并嚴(yán)重影響駕駛員的工作環(huán)境,對(duì)駕駛員的生理和心理健康造成危害[3-5]。振動(dòng)問題已經(jīng)成為制約中國(guó)聯(lián)合收獲機(jī)向高可靠性和舒適性發(fā)展的瓶頸[6]。
目前農(nóng)用機(jī)械的振動(dòng)越來(lái)越受到國(guó)內(nèi)外研究者的關(guān)注[7-12],主要集中在駕駛座椅振動(dòng)和舒適性分析[13]、振動(dòng)模型的建立[14]、割刀和割臺(tái)振動(dòng)[15-17]、風(fēng)機(jī)的振動(dòng)噪聲[18]、底盤機(jī)架模態(tài)分析[19]、傳感器振動(dòng)特性[20]等方面。Hostens等[21]對(duì)聯(lián)合收獲機(jī)在混凝土路面和田間不同工況下振動(dòng)的研究發(fā)現(xiàn)駕駛室中的低頻振動(dòng)更為嚴(yán)重,在聯(lián)合收獲機(jī)舒適性評(píng)價(jià)和駕駛室或座椅設(shè)計(jì)中要特別重視低頻振動(dòng)。王芬娥等[22]測(cè)試了某型號(hào)聯(lián)合收獲機(jī)在不同工況下的振動(dòng)特性,得到了其振動(dòng)加速度有效值和振動(dòng)主頻。周林等[23]通過搭建玉米聯(lián)合收獲機(jī)駕駛室的振動(dòng)實(shí)時(shí)監(jiān)控系統(tǒng)并計(jì)算振動(dòng)總量對(duì)玉米聯(lián)合收獲機(jī)的的舒適性進(jìn)行了評(píng)價(jià),發(fā)現(xiàn)垂直方向上的低頻(2~20 Hz)大振幅振動(dòng)對(duì)人體的影響最大。姚艷春等[24]通過振動(dòng)測(cè)試和模態(tài)分方法,分析車架田間振動(dòng)特性,并對(duì)車架進(jìn)行優(yōu)化,避開了共振主頻,使優(yōu)化后車架無(wú)故障時(shí)間由20 h提升到60 h。
上述研究多是基于空載工況下開展的測(cè)試與分析,關(guān)于履帶式全喂入聯(lián)合收獲機(jī)田間收獲工況下振動(dòng)測(cè)試與分析成果還不多見。實(shí)際上田間收獲是聯(lián)合收獲機(jī)工作時(shí)間最長(zhǎng)的工況,工作部件多,振動(dòng)最復(fù)雜,而喂入量是聯(lián)合收獲機(jī)的主要設(shè)計(jì)參數(shù)之一[25],工作部件的結(jié)構(gòu)和運(yùn)動(dòng)參數(shù)主要也是依據(jù)喂入量來(lái)設(shè)計(jì)的,喂入量的不同會(huì)使各部件處于不同負(fù)荷和工作狀態(tài)會(huì)影響整機(jī)振動(dòng)。本文根據(jù)履帶式全喂入稻麥聯(lián)合收獲機(jī)的結(jié)構(gòu)特點(diǎn),以沃得銳龍4LZ-5.0E履帶式全喂入稻麥聯(lián)合收獲機(jī)(以下簡(jiǎn)稱4LZ-5.0E聯(lián)合收獲機(jī))為研究對(duì)象,開展不同喂入量收獲工況下整機(jī)振動(dòng)測(cè)試研究,找出喂入量對(duì)整機(jī)振動(dòng)的影響,以期為降低聯(lián)合收獲機(jī)整機(jī)振動(dòng)提供參考。
履帶式稻麥聯(lián)合收獲機(jī)的振動(dòng),可認(rèn)為是一個(gè)多自由度系統(tǒng)的振動(dòng)[26]。4LZ-5.0E聯(lián)合收獲機(jī)主要包括割臺(tái)1、輸送槽2、清選裝置3、脫粒裝置4、糧箱5、駕駛操縱臺(tái)6,如圖1a所示,其中割臺(tái)和輸送槽均是由薄板材焊接而成的殼體內(nèi)部為空腔,如圖1b所示。田間收獲時(shí),割下的作物莖稈向后進(jìn)入割臺(tái),莖稈在割臺(tái)上工作部件的作用下向后充入輸送槽內(nèi)并進(jìn)入脫粒裝置,脫下的籽粒落入清選裝置被清選后送入糧箱而秸稈經(jīng)脫粒裝置進(jìn)入粉碎機(jī)粉碎排至田間。

1.割臺(tái) 2.輸送槽 3.清選裝置 4.脫粒裝置 5.糧箱 6.駕駛操縱臺(tái)
聯(lián)合收獲機(jī)主要振源有發(fā)動(dòng)機(jī),往復(fù)運(yùn)動(dòng)的割刀、振動(dòng)篩,回轉(zhuǎn)運(yùn)動(dòng)的攪龍、脫粒滾筒、風(fēng)機(jī)、撥禾輪,輸送槽,傳動(dòng)機(jī)構(gòu)等部件。聯(lián)合收獲機(jī)在田間收獲時(shí)要求發(fā)動(dòng)機(jī)必須在額定轉(zhuǎn)速(2 710 r/min),通過手柄可以改變機(jī)器行走速度,但發(fā)動(dòng)機(jī)轉(zhuǎn)速保持仍不變,以保證各工作部件均在額定轉(zhuǎn)速工作獲得較好的收獲性能和效率,因此,當(dāng)發(fā)動(dòng)機(jī)轉(zhuǎn)速為2 710 r/min時(shí),利用非接觸式轉(zhuǎn)速表測(cè)得的4LZ-5.0E聯(lián)合收獲機(jī)田間收獲時(shí)主要部件轉(zhuǎn)速并利用式(1)計(jì)算出其理論振動(dòng)頻率,如表1所示。

式中為理論激振頻率,Hz;為測(cè)量的各部件驅(qū)動(dòng)輪的轉(zhuǎn)速,r/min。

表1 4LZ-5.0E聯(lián)合收獲機(jī)田間收獲工況主要工作參數(shù)
四缸柴油發(fā)動(dòng)機(jī)燃燒激振頻率1(Hz)計(jì)算公式[27]為

式中1為發(fā)動(dòng)機(jī)轉(zhuǎn)速,r/min;為發(fā)動(dòng)機(jī)氣缸數(shù);為發(fā)動(dòng)機(jī)沖程數(shù)。
由往復(fù)運(yùn)動(dòng)的質(zhì)量和不平衡的旋轉(zhuǎn)質(zhì)量引起的慣性力激振頻率f(Hz)計(jì)算公式為[26]

式中為比例系數(shù),此發(fā)動(dòng)機(jī)中為2。
由表1和式(2)、式(3)得,發(fā)動(dòng)機(jī)轉(zhuǎn)頻為45.17 Hz,發(fā)動(dòng)機(jī)燃燒激振頻率和慣性力激振頻率為90.33 Hz。
振動(dòng)測(cè)試使用DH5902動(dòng)態(tài)信號(hào)測(cè)試分析系統(tǒng)(硬件為DH5902信號(hào)采集儀和三向加速度傳感器)對(duì)4LZ-5.0E聯(lián)合收獲機(jī)在不同喂入量下的田間收獲工況進(jìn)行振動(dòng)測(cè)試,測(cè)試儀器主要性能參數(shù)如表2所示。

表2 測(cè)試儀器主要性能參數(shù)
由于通過控制機(jī)器作業(yè)速度來(lái)保持喂入量的穩(wěn)定等的研究已經(jīng)取得了一些進(jìn)展[28-29],本論文采用通過控制前進(jìn)速度來(lái)改變喂入量的方法。為比較不同喂入量田間收獲工況下整機(jī)振動(dòng)的變化,以保證能實(shí)現(xiàn)順暢收獲,不堵草的最大速度為快速,取其大約一半的速度為慢速。4LZ-5.0E聯(lián)合收獲機(jī)割幅為2 m并分別以快速(1.14 m/s)和慢速(0.72 m/s)收獲以及空載(0 m/s)3個(gè)方案進(jìn)行試驗(yàn),具體方案如表3所示。

表3 振動(dòng)試驗(yàn)測(cè)試方案
注:機(jī)器狀態(tài)為田間收獲,發(fā)動(dòng)機(jī)轉(zhuǎn)速2 710 r·min-1,工作部件全部運(yùn)行。
Note: The machine harvested in the field and engine speed was 2 710 r·min-1with all components working.
聯(lián)合收獲機(jī)割臺(tái)的喂入量可由式(4)計(jì)算。

式中1為聯(lián)合收獲機(jī)割臺(tái)的喂入量,kg/s;為作物籽粒平均產(chǎn)量,kg/m2;為作物的谷草比;為割臺(tái)幅寬,m;為機(jī)器前進(jìn)速度,m/s。
在江蘇沃得農(nóng)業(yè)機(jī)械有限公司的試驗(yàn)基地選取一段平整田塊對(duì)4LZ-5.0E聯(lián)合收獲機(jī)田間收獲工況下整機(jī)振動(dòng)進(jìn)行測(cè)試,振動(dòng)測(cè)試現(xiàn)場(chǎng)如圖2所示。每次試驗(yàn)前進(jìn)距離為35 m,試驗(yàn)區(qū)前預(yù)留5 m作物以確保進(jìn)入試驗(yàn)區(qū)前收獲機(jī)以穩(wěn)定喂入量工作,利用采集儀在試驗(yàn)區(qū)內(nèi)記錄25 s振動(dòng)數(shù)據(jù),每次試驗(yàn)前均清理機(jī)具,缷糧。試驗(yàn)時(shí)僅通過無(wú)級(jí)變速器改變機(jī)器前進(jìn)速度來(lái)改變喂入量,發(fā)動(dòng)機(jī)轉(zhuǎn)速始終在額定轉(zhuǎn)速(2 710 r/min)以保證各部件工作參數(shù)保持不變。

1.脫粒滾筒 2.粉碎機(jī) 3.機(jī)架 4.信號(hào)采集儀 5.發(fā)動(dòng)機(jī) 6.底盤 7.割臺(tái) 8.駕駛操縱臺(tái)
試驗(yàn)作物品種:鎮(zhèn)麥168,作物自然高度90.0 cm,籽粒千粒質(zhì)量41.0 g,籽粒含水率14.7%,莖稈含水率:44.5%,平均產(chǎn)量6 605 kg/hm2,草谷比1.57。
根據(jù)4LZ-5.0E聯(lián)合收獲機(jī)的結(jié)構(gòu)特點(diǎn),將測(cè)點(diǎn)布置在主要工作部件處和激振源附近,以便準(zhǔn)確獲得各部分的實(shí)際振動(dòng),共布置如表4所示的12個(gè)測(cè)點(diǎn)。

表4 測(cè)點(diǎn)的分布
為研究方便,通過選擇三向加速度傳感器合適安裝方向和信號(hào)采集儀連接通道,使DH5902信號(hào)采集儀采集到的、、通道信號(hào)分別對(duì)應(yīng)4LZ-5.0E聯(lián)合收獲機(jī)的前后(前進(jìn)方向)、左右(橫向)、上下(豎直方向)3個(gè)方向。試驗(yàn)時(shí),設(shè)置測(cè)試系統(tǒng)采樣方式為連續(xù)采樣,采樣頻率為2 kHz,分析頻率781.25 Hz,時(shí)域點(diǎn)數(shù)為4 096,頻域線數(shù)為1 600,平均次數(shù)為10,振動(dòng)信號(hào)每次試驗(yàn)方案采集3次,取數(shù)據(jù)較好一組數(shù)據(jù)進(jìn)行分析。
在、、方向上12個(gè)測(cè)點(diǎn)測(cè)得的時(shí)域信號(hào)中選取信號(hào)波動(dòng)較小的部分經(jīng)快速傅里葉變換變換后可得到頻譜圖。為研究聯(lián)合收獲機(jī)田間收獲時(shí)的振動(dòng)特性,對(duì)上述振動(dòng)試驗(yàn)測(cè)試方案(表3)中方案2(喂入量為2.44 kg/s)的頻域信號(hào)(≤200 Hz)信號(hào)進(jìn)行分析,頻譜圖中各測(cè)點(diǎn)振幅的前4個(gè)峰值及對(duì)應(yīng)振動(dòng)頻率如表5所示。
由表5可知:1)聯(lián)合收獲機(jī)在方向、方向、方向上的振動(dòng)分別在測(cè)點(diǎn)12底盤機(jī)架右前、測(cè)點(diǎn)5脫粒滾筒驅(qū)動(dòng)軸前支座、測(cè)點(diǎn)11發(fā)動(dòng)機(jī)機(jī)腳支座處振幅達(dá)到最大值分別為4.23 m/s2(7.08 Hz,割刀和振動(dòng)篩工作頻率)、4.75 m/s2(22.95 Hz,脫粒滾筒轉(zhuǎn)頻11.47 Hz的倍頻)和4.29 m/s2(180.66 Hz,燃燒激振頻率90.33 Hz的倍頻),說(shuō)明振動(dòng)篩的前后振動(dòng)傳遞到底盤機(jī)架右前造成的振動(dòng)、脫粒滾筒轉(zhuǎn)動(dòng)造成的左右振動(dòng)和發(fā)動(dòng)機(jī)燃燒力矩產(chǎn)生的上下振動(dòng)是聯(lián)合收獲機(jī)的主要激振源。在設(shè)計(jì)時(shí)可以考慮從改進(jìn)脫粒分離機(jī)架、清選機(jī)架結(jié)構(gòu),提高其剛度,改進(jìn)發(fā)動(dòng)機(jī)懸架以及在底盤機(jī)架連接之間增加隔振結(jié)構(gòu)等方面入手減少振幅。
2)測(cè)點(diǎn)1割刀傳動(dòng)軸支座、測(cè)點(diǎn)4輸送槽正上方、測(cè)點(diǎn)7振動(dòng)篩驅(qū)動(dòng)軸支座、測(cè)點(diǎn)8風(fēng)機(jī)驅(qū)動(dòng)軸支座、測(cè)點(diǎn)9輸糧攪龍驅(qū)動(dòng)軸支座處的主要峰值振動(dòng)頻率中均存在割刀和振動(dòng)篩的工作頻率(7.08 Hz),對(duì)應(yīng)振幅如表5中所示,由此可看出割刀往復(fù)振動(dòng)和振動(dòng)篩往復(fù)振動(dòng)主要沿著機(jī)架傳遞到其他部分。測(cè)點(diǎn)12底盤機(jī)架右前處的振動(dòng)頻率7.08 Hz在、、3個(gè)方向上的振幅均達(dá)到了3.5 m/s2以上,并且振幅為峰值2振幅的2~3倍,說(shuō)明底盤機(jī)架右前處在7.08 Hz可能發(fā)生了局部共振。以上測(cè)點(diǎn)說(shuō)明割刀和振動(dòng)篩的往復(fù)運(yùn)動(dòng)引起的振動(dòng)是整機(jī)振動(dòng)中的重要組成部分,在設(shè)計(jì)時(shí)應(yīng)該在割刀、輸送槽、振動(dòng)篩、風(fēng)機(jī)、發(fā)動(dòng)機(jī)與機(jī)架之間增加隔振結(jié)構(gòu),也可在傳遞振動(dòng)的機(jī)架上增加阻尼塊使振動(dòng)衰減,同時(shí)對(duì)底盤機(jī)架結(jié)構(gòu)進(jìn)行改進(jìn),尤其是改進(jìn)右前部的局部模態(tài),避免局部共振的發(fā)生。
3)測(cè)點(diǎn)1割刀傳動(dòng)軸支座處在、、方向上的峰值頻率均為風(fēng)機(jī)和中間軸轉(zhuǎn)頻24.17 Hz的倍頻(48.34 Hz),振幅分別為1.56、1.54、1.31 m/s2;測(cè)點(diǎn)2割臺(tái)后立柱在、方向的主要振動(dòng)頻率也是48.34 Hz,振幅分別為0.92、1.54 m/s2,說(shuō)明收獲過程中,喂入不均勻造成風(fēng)機(jī)和中間軸負(fù)荷變化形成的激振經(jīng)清選機(jī)架、脫粒分離機(jī)架、輸送槽機(jī)架傳至割臺(tái),引起了割臺(tái)的明顯振動(dòng)。測(cè)點(diǎn)5脫粒滾筒驅(qū)動(dòng)軸前支座在、、3個(gè)方向上的峰值振動(dòng)頻率均有脫粒滾筒轉(zhuǎn)頻11.47 Hz的倍頻(22.95 Hz),且振幅分別為3.08、4.75、2.7 m/s2,說(shuō)明脫粒滾筒的轉(zhuǎn)動(dòng)是造成滾筒驅(qū)動(dòng)軸前支座處的強(qiáng)烈振動(dòng)的主要原因。另外測(cè)點(diǎn)3輸送槽驅(qū)動(dòng)軸支座在、、方向上的峰值1振動(dòng)頻率也為22.95 Hz,且振幅分別為3.04、2.09、2.24 m/s2,而測(cè)點(diǎn)6脫粒滾筒后支座在22.95 Hz處也有較大的振幅,也說(shuō)明脫粒滾筒的轉(zhuǎn)動(dòng)是造成輸送槽驅(qū)動(dòng)軸支座和脫粒滾筒后支座振動(dòng)的主要原因。究其原因,田間收獲時(shí),脫粒滾筒作為聯(lián)合收獲機(jī)負(fù)荷最大(功耗約30 kW)的工作部件,由于作物疏密、地形起伏、割茬波動(dòng)、草谷比變化等造成的喂入不均勻以及滾筒齒桿磨損等形成的不平衡力,導(dǎo)致脫粒滾筒在、、3個(gè)方向上形成了劇烈激振。
4)測(cè)點(diǎn)10駕駛座椅支座和測(cè)點(diǎn)11發(fā)動(dòng)機(jī)機(jī)腳支座的主要振動(dòng)均在方向上。測(cè)點(diǎn)11的峰值1振動(dòng)頻率為燃燒激振頻率的倍頻(180.66 Hz),振幅為4.29 m/s2,而測(cè)點(diǎn)10在180.66 Hz的振幅為1.01 m/s2;測(cè)點(diǎn)11在發(fā)動(dòng)機(jī)燃燒激振頻率(90.33 Hz)的振幅為1.03 m/s2,而測(cè)點(diǎn)10的峰值1振動(dòng)頻率為90.33 Hz,振幅為2.36 m/s2(為峰值2振幅的2倍),這說(shuō)明發(fā)動(dòng)機(jī)燃燒激振力是引起駕駛座上下方向振動(dòng)的主要原因,駕駛臺(tái)能有效降低較高頻率(≥150 Hz)的振動(dòng),卻將燃燒激振頻率90.33 Hz的振動(dòng)放大為原來(lái)的2.3倍。在駕駛臺(tái)設(shè)計(jì)過程中,應(yīng)在底盤機(jī)架和駕駛臺(tái)之間增加隔振結(jié)構(gòu),降低較低頻率(<150 Hz)振動(dòng)的傳遞,提高駕駛員的駕駛舒適性。
為研究聯(lián)合收獲機(jī)同一測(cè)點(diǎn)處不同喂入量下的振動(dòng)強(qiáng)弱,對(duì)上述振動(dòng)試驗(yàn)測(cè)試方案(表3)中的3種方案的頻域信號(hào)進(jìn)行分析比較。為準(zhǔn)確反映每個(gè)測(cè)點(diǎn)處振動(dòng)的強(qiáng)度,利用未經(jīng)計(jì)權(quán)的振動(dòng)加速度均方根值作為評(píng)價(jià)標(biāo)準(zhǔn)[30]。首先利用DH5902動(dòng)態(tài)信號(hào)測(cè)試分析系統(tǒng)對(duì)每個(gè)通道信號(hào)頻譜圖中的的2~250 Hz進(jìn)行1/3倍頻程分析得到各測(cè)點(diǎn)在、、方向上1/3倍頻帶,測(cè)點(diǎn)12在方向上的20個(gè)1/3倍頻帶如表6所示,然后對(duì)各測(cè)點(diǎn)在、、方向上的1/3倍頻程帶利用式(5)計(jì)算各個(gè)測(cè)點(diǎn)單方向的振動(dòng)加速度均方根值,對(duì)各測(cè)點(diǎn)在、、方向上的振動(dòng)信號(hào)整理和計(jì)算得到的加速度均方根值如圖3所示。

式中a為第個(gè)1/3倍頻程帶的加速度均方根值,m/s2;為單個(gè)方向的加速度均方根值,m/s2;為1/3倍頻程帶的個(gè)數(shù)。
對(duì)正交坐標(biāo)系下各測(cè)點(diǎn)的振動(dòng)總量可由式(6)計(jì)算得到的加速度均方根值表示。

式中a為各測(cè)點(diǎn)均方根加速度的振動(dòng)總量,m/s2;a、a、a分別為該測(cè)點(diǎn)在、、3個(gè)方向上的加速度均方根值,m/s2。由式(5)、(6)可計(jì)算得各測(cè)點(diǎn)的振動(dòng)總量如表7所示。
由圖3和表7可以看出:測(cè)點(diǎn)1割刀傳動(dòng)軸支座處、測(cè)點(diǎn)2割臺(tái)后立柱處、測(cè)點(diǎn)4輸送槽正上方的振動(dòng)總量在有作物喂入后(喂入量為2.44 kg/s)振動(dòng)明顯降低,分別降低35%、25%、39%,但是隨喂入量的再次增大(喂入量為3.87 kg/s)測(cè)點(diǎn)的振動(dòng)總量卻無(wú)明顯變化(變化范圍在10%以內(nèi)),因?yàn)楦钆_(tái)和輸送槽均是由薄板材焊接而成的殼體內(nèi)部為空腔(如圖1b所示),作物充入兩者組成的腔體后對(duì)割臺(tái)和輸送槽的振動(dòng)起到了明顯的吸收作用,其中測(cè)點(diǎn)1主要降低了方向上的振動(dòng)(57%),測(cè)點(diǎn)4降低了和方向的振動(dòng)(55%、44%),測(cè)點(diǎn)2在、方向上的振動(dòng)有所降低(28%、14%),但作物喂入量的變化沒有引起割臺(tái)和輸送槽振動(dòng)的明顯變化。

注:2、4、6、8、10、12、14、16為加速度均方根值,單位為m·s-2。

表7 各測(cè)點(diǎn)振動(dòng)總量的加速度均方根值
測(cè)點(diǎn)3輸送槽驅(qū)動(dòng)軸支座、測(cè)點(diǎn)5脫粒滾筒驅(qū)動(dòng)軸前支座處、測(cè)點(diǎn)6脫粒滾筒后支座處的振動(dòng)總量在喂入量為2.44 kg/s時(shí)比無(wú)作物喂入時(shí)顯著增大,分別增加90%、87%、149%,而且在、、方向上的增加均非常明顯(50%以上),其中測(cè)點(diǎn)6在方向上的振動(dòng)增加最多(266%),這是因?yàn)樽魑锏奈谷胧沟幂斔筒?、脫粒滾筒上增加了負(fù)荷,作物在輸送槽內(nèi)輸送和脫粒滾筒中脫粒時(shí)帶來(lái)的負(fù)荷波動(dòng)產(chǎn)生了劇烈振動(dòng),而其中測(cè)點(diǎn)6振動(dòng)增加最大也是因?yàn)槊摿L筒是聯(lián)合收獲機(jī)田間收獲負(fù)荷最大(功耗約30 kW)的工作部件,易產(chǎn)生較大的不平衡力,導(dǎo)致脫粒滾筒處振動(dòng)增加最多。而隨著喂入量增大到3.87 kg/s后由于作物充滿輸送槽內(nèi)和脫粒間隙,一定程度減小了其負(fù)荷的波動(dòng)和作用其上的不平衡力使其振動(dòng)總量有所減少,分別減少16%、13%、14%,因此收獲時(shí)應(yīng)使機(jī)器保持一定的喂入量,可以降低整機(jī)振動(dòng)。
測(cè)點(diǎn)10駕駛座椅支座處、測(cè)點(diǎn)11發(fā)動(dòng)機(jī)機(jī)腳支座處、測(cè)點(diǎn)12底盤機(jī)架右前位置處的振動(dòng)總量在喂入量為2.44 kg/s時(shí)比無(wú)作物喂入時(shí)分別增大40%、59%、31%,并且振動(dòng)總量隨作物喂入量的增加(喂入量為3.87 kg/s)而分別增加11%、37%、17%。另外由圖3可知這3個(gè)測(cè)點(diǎn)在、、3個(gè)方向上的振動(dòng)均有不同程度的增加,這說(shuō)明在駕駛座椅支座、發(fā)動(dòng)機(jī)機(jī)腳支座和底盤機(jī)架測(cè)點(diǎn)處的振動(dòng)與作物喂入量呈現(xiàn)正相關(guān)性。
1)田間收獲工況下,振動(dòng)篩的前后往復(fù)運(yùn)動(dòng)、脫粒滾筒引起的左右振動(dòng)和發(fā)動(dòng)機(jī)產(chǎn)生上下振動(dòng)是聯(lián)合收獲機(jī)在、、3個(gè)方向上的主要振動(dòng)源;另外,脫粒滾筒的回轉(zhuǎn)運(yùn)動(dòng)產(chǎn)生的振動(dòng)是整機(jī)振動(dòng)中最劇烈的部分;由于風(fēng)機(jī)、振動(dòng)篩、發(fā)動(dòng)機(jī)、變速箱、駕駛座椅等部件均安裝在聯(lián)合收獲機(jī)機(jī)架上,這些激振源是通過機(jī)架將振動(dòng)傳遞到聯(lián)合收獲機(jī)各部分的。
2)在田間收獲時(shí),由于作物喂入使作物秸稈充入割臺(tái)和輸送槽組成的腔體結(jié)構(gòu)對(duì)割臺(tái)和輸送槽的振動(dòng)起到了吸收作用,使得割臺(tái)和輸送槽測(cè)點(diǎn)處的振動(dòng)總量下降25%、39%。由于作物的喂入使得輸送槽驅(qū)動(dòng)軸和脫粒滾筒上的負(fù)荷增大并產(chǎn)生波動(dòng),當(dāng)喂入量為2.44 kg/s時(shí),其上測(cè)點(diǎn)的振動(dòng)比無(wú)作物喂入時(shí)分別增大了90%、149%。但隨著喂入量的增大,作物充滿輸送槽和脫粒間隙,使得負(fù)荷波動(dòng)減小,當(dāng)喂入量為3.87 kg/s時(shí),振動(dòng)總量減少約15%;而駕駛座椅、發(fā)動(dòng)機(jī)機(jī)架和底盤機(jī)架上測(cè)點(diǎn)處的振動(dòng)總量與作物喂入量呈正相關(guān)性。
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Vibration measure and analysis of crawler-type rice and wheat combine harvester in field harvesting condition
Gao Zhipeng, Xu Lizhang※, Li Yaoming, Wang Yading, Sun Pengpeng
(,,,212013,)
The paper aimed at studying the vibration characteristics of combine harvester in field harvest and the vibration characteristics of combine harvester in different feeding conditions. Taking 4LZ-5.0E crawler-type rice and wheat full-feeding combine harvester manufactured by World Agricultural Machinery Co. Ltd. as study objection, the investigation designed 12 measuring points on the body of the combine harvester to carry out vibration test by DH5902 dynamic signal testing and analysis system. The measuring points were located near the main working components and excitation sources according to the structural characteristics. In the experiment, the combine harvester worked at the speeds of 0, 0.72 and 1.14 m/s respectively. In the paper, only the speed of the combine harvester was changed by hydro static transmission (HST) while other operating parameters were fixed. The aim was to insure the changes in vibration conditions only caused by the changes in feeding quantities. In the research, the spectrum could be gotten from time-domain signal of measuring points by Fourier transform. The physical quantities could be obtained from spectrum diagrams such as vibration frequency of the signal, distribution and peak. In the analysis process, root mean square (RMS) value of vibration acceleration was designated as the assessment standard. And it was calculated by 1/3 octave band of each measurement point in the direction of,and, which was obtained from the spectrum received by DH5902 dynamic signal testing and analysis system. The RMS values of vibration acceleration were used as the signs of the intensity of vibration. The analysis indicated that vibrating sieve, threshing cylinder, and engine were the main vibration sources in the forward-backward, left-right, up-down direction, respectively. The vibration caused by the reciprocating motions of cutter and vibrating sieve was an important part of the whole combine harvester vibration. The rotation of the threshing cylinder was the main source of the strong vibration of the front and back support, the drive shaft support. The vibration from vibration sources could be transmitted to each part of the combine harvester through the frame. The engine combustion excitation force was the main source to the vibration in up-down direction, and the cab could effectively reduce the vibration of high frequency (≥150 Hz), but the vibration of combustion excitation frequency (90.33 Hz) was 2.3 times as large as before. In the field experiment of wheat harvest, total vibration of the measuring points on header and the conveying trough respectively decreased by 25% and 39%. The cavity structure composed of header and the conveying trough absorbed some vibration when the crop was fed into it. The feeding of crop caused the magnifying of load on the drive shaft of conveying trough and threshing cylinder. When the feeding quantity was 2.44 kg/s, the total vibration of the measuring points of drive shaft on conveying trough and the threshing cylinder increased by 90% and 149% respectively compared with that when no crop was fed. But the space was filled when feeding quantity was increased to 3.87 kg/s, and the total vibration was decreased by about 15%. The paper suggests that vibration isolation device should be installed between vibrating sieve, threshing cylinder, engine and chassis frame. To reduce vibration, the feeding quantity of threshing cylinder should be constant and vibration isolation device should also be installed on the connection location of the chassis frame. The vibrations of the measuring points on the seat support, engine support and chassis frame are positively correlated with feeding quantity. The result provides a basis for reducing the vibration and improving the driving comfort of the crawler-type rice and wheat combine harvester.
combines; vibrations; noise; different feeding quantities; field harvesting
10.11975/j.issn.1002-6819.2017.20.006
S225.3; TB533+.1
A
1002-6819(2017)-20-0048-08
2017-05-05
2017-09-12
“十三五”國(guó)家重點(diǎn)研發(fā)計(jì)劃課題(2016YFD0702101-1);江蘇省高校優(yōu)勢(shì)學(xué)科建設(shè)工程資助項(xiàng)目(蘇財(cái)教(2011)8號(hào))
高志朋,主要從事履帶式聯(lián)合收獲機(jī)振動(dòng)分析與減振優(yōu)化的研究。Email:2211516036@stmail.ujs.edu.cn
※通信作者:徐立章,研究員,博士生導(dǎo)師,主要從事收獲機(jī)械設(shè)計(jì)及理論研究。Email:justxlz@ujs.edu.cn
高志朋,徐立章,李耀明,王亞丁,孫朋朋. 履帶式稻麥聯(lián)合收獲機(jī)田間收獲工況下振動(dòng)測(cè)試與分析[J]. 農(nóng)業(yè)工程學(xué)報(bào),2017,33(20):48-55. doi:10.11975/j.issn.1002-6819.2017.20.006 http://www.tcsae.org
Gao Zhipeng, Xu Lizhang, Li Yaoming, Wang Yading, Sun Pengpeng. Vibration measure and analysis of crawler-type rice and wheat combine harvester in field harvesting condition[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(20): 48-55. (in Chinese with English abstract) doi:10.11975/j.issn.1002-6819.2017.20.006 http://www.tcsae.org