外文翻譯--驅(qū)動橋振動與噪聲的研究

1、<p><b>　　中文2715字</b></p><p>　　驅(qū)動橋振動與噪聲的研究</p><p>　　賴菲 鄧兆祥 張建</p><p>　　（中國重慶大學機械傳動國家重點實驗室）</p><p>　　摘要：因為后橋是振動和噪聲的主要來源，所以通過構建整個后橋的裝配模型，然后采取瞬態(tài)、諧波和噪聲分析。

2、本文利用CAD / CAE技術分析了一種小型汽車后橋的噪聲,然后提出結構改良意見。在不改變其原有結構和做大的修改的情況下，介紹了通過利用采用柄的方法改進主要噪音源的結構。仿真結果表明對后橋結構的改進可有效減少噪音。</p><p>　　關鍵詞： 驅(qū)動橋，振動，噪音，邊界元，有限元 引言 后橋是汽車動力傳輸機構的一個主要噪音源。它的齒輪傳動裝置和軸類裝置都能產(chǎn)生噪音，外殼的振動也能產(chǎn)生噪音。此外，由于后

3、橋是由懸架支撐的，后橋的彎曲和扭轉振動和道路的崎嶇不平,都能產(chǎn)生很大的噪音。</p><p>　　隨著軟件開發(fā)、硬件、現(xiàn)代設計與分析技術的發(fā)展, 使用現(xiàn)代分析技術實驗和檢測來解決問題已經(jīng)成為了一種趨勢。在這篇文章中,將用仿真軟件ANSYS和ADAMS來分析動態(tài)特性和激振力。然后用SYSNOISE計算輻射由后橋表面振動產(chǎn)生的噪聲。在此基礎上,準確預測出后橋的噪音并采取相應的改進措施。采用數(shù)值分析的方法來研究后橋的噪

4、音問題可以節(jié)省時間、勞動和金錢,同時,它也可以獲得更多相關信息。</p><p>　　1. 后橋的建模及邊界條件的確定</p><p>　　后橋主要是由主減速器、差速器、半軸和后橋殼組成。它的功能是傳遞發(fā)動機扭矩，通過驅(qū)動軸驅(qū)動車輪，并減速增扭。它也支撐和保護后橋差速器、半軸等,同時也對車輪軸向定位并支撐車身和從動軸的其它組件。在行駛時,它還承受著力和路面通過車輪傳遞的力矩,并通過懸架傳遞

5、到車身。</p><p><b>　　邊界條件</b></p><p><b>　　FFT </b></p><p>　　不滿足 </p><p><b>　　滿足</b></p><p>　　車輛主減速器廣泛運用

6、雙曲面斜齒輪，這種錐齒輪運轉在十字軸中。由于小、大齒輪得軸線不相交,所以偏離一些距離。當它們進行嚙合時,它們可以在圓周方向 很順暢的運轉,在齒頂方向接觸的撞擊很輕。為了降低了振動動和噪音,一些條件必須要滿足:1)使用大的重疊系數(shù),保證交配齒輪2 ~ 3個或更多之間;(2)使用齒數(shù)少的小齒輪以獲得大傳動比、節(jié)省空間;3)裝配精確至少達到50%的表面接觸</p><p>　　表1的數(shù)據(jù)的齒輪

7、 主動齒輪 從動齒輪 螺旋角a 20 20 齒頂高系數(shù)h*a 0.82 0.82 頂隙系數(shù)C * 0.188 0.188 變位系數(shù)x 0.375 -0.375 分錐角δ 11.041 78.959 分度圓直徑d

8、 32.336 164.984 錐距R 84.048 84.048 齒寬系數(shù)ΦR 0.365 0.297 寬度b 30.706 25 齒頂高ha 4.809 1.791 齒高h 7.356 7.356 齒根高hf

9、 2.547 5.565 齒頂圓直徑直</p><p>　　1.1 有限元區(qū)域的劃分 汽車后橋殼材料是其密度7850 kg/m3的鍛鐵，楊氏彈性模量2.07e5Mpa，</p><p>　　泊松比0.28，剪切模量

10、為8.02e4，使用163系元素。驅(qū)動裝置的材料,其密度個20GrMnTi鋼公斤/方,年輕的彈性模量的2.1e5Mpa、泊松比0.3,8.02e4剪切模量,</p><p>　　利用solid164元素。</p><p>　　圖2 齒輪和驅(qū)動軸的有限元建模 </p><p>　　圖3 后橋的固定裝配 </p><p>　　1.2

11、確定邊界條件 邊界條件下的振動分析,包括:驅(qū)動后橋從動齒輪的速度,齒輪的初始速度負荷、橋殼的約束條件。</p><p>　　1.2.1 傳動齒輪的速度的影響 1）這種驅(qū)動輪的型號是155R13，當充滿氣時車輪直徑為576mm。</p><p>　　2)假定車輪的線速度是90km/h,相當于25m/s,因此車輪的角速度是86.8 rad/s。</p><p

12、>　　由于主動輪和從動輪的傳動比是41：8，所以主動輪的角速度為：86.8*41/8=444.88rad/s。輸入軸和輸出軸的關系表達式是：</p><p>　　w2為輸出角速度，w1為輸入恒定角速度，A1角輸入軸與連接軸之間的角度，A2輸出軸與連接軸之間的角度，φ1是輸入軸的旋轉速度。a1=a2=a=7.5°, w1=444.88rad/s.</p><p>　　1.2.

13、2 從動齒輪的初始速度負荷 </p><p>　　事實上車輛在剛起步時速度不可能達到90 km/h,但逐漸增加到平穩(wěn)的狀態(tài)。如果起步速度不合適或者不太合適,可能對齒輪產(chǎn)生劇烈的沖擊。只有應用精確地起步速度，齒輪的變形才會有所改善。 1.2.3 后橋殼約束條件 殼體承受的來自齒輪緊密配合時表面沖擊產(chǎn)生的載荷。這種沖擊通過軸和軸承傳到殼體并引起殼體的震動。</p><p>　　圖

14、4 后橋殼約束 2.提取后橋瞬態(tài)分析的時間</p><p>　　瞬態(tài)分析主要是為了提取后橋的負載數(shù)據(jù)。這種處理軸承和外殼的方法叫做交點法。所以表面的節(jié)點(圖C、D、E)需要分析?？偣灿?52個節(jié)點。通過分析軸承軸向和圓周不同的節(jié)點,我們可以發(fā)現(xiàn)節(jié)點的反應是幾乎相同的。所以當處理負荷數(shù)據(jù)時,我們可以把時域曲線節(jié)點與軸承上的點等同。這個簡化圖是合適的,也減少了工作量。在得到時域信號后，我們需要把它轉換成頻域信號

15、:1)以發(fā)現(xiàn)什么頻率能夠引起大的振動，然后著重研究這些頻率并最終減少振動,2)在SYSNOISE軟件里用他們作為負荷數(shù)據(jù)。 從圖中,我們可以發(fā)現(xiàn)當頻率為128.57Hz,200Hz ，71.43Hz，271.43Hz時，引起比較大的振動。所以在SYSNOISE軟件的諧響應分析里三種不同的頻率的負荷數(shù)據(jù)是非常重要的。(由于D、E的響應非常相像,所以下圖只列出了D的響應)。</p><p>　　圖5 在

16、C頻率為2000Hz頻域響應</p><p>　　圖6 在D為頻率為2000Hz的頻域響應</p><p>　　3. 后橋的噪聲分析 首先,我們進口的位移響應的結果及相應的諧波頻率。然后我們可以用邊界元法解決噪音問題。這樣做的目的是要找出發(fā)動機的主要噪聲源,并為進一步改進提供證明。一些文檔指出后橋的噪音是由于結構表面的振動產(chǎn)生的, 例如后橋殼。參照有限元建模的研究結果，我們知

17、道殼的振動主要集中在后蓋殼和主減速器殼，它們都位于殼的中間部分。所以當我們定點是，我們應著重考慮中間部分的噪聲輻射。</p><p><b>　　圖7 分布圖 </b></p><p>　　在128.57Hz頻率下的聲壓級(SPL)如下:</p><p>　　圖8 后殼的聲壓力</p><p>　　圖9 上殼

18、的聲壓力</p><p>　　從上圖,我們可以把這個主要聲源定位在主減速器齒輪和后殼。大量的昏黃</p><p>　　色出現(xiàn)在這些地方并且這些地方的聲壓級是在94.19db和98.7db之間。</p><p>　　為了便于比較，我們列出的計算，所有的頻率，結果如下： 表2的所有頻率的計算結果 </p><p>　　相比之下，我們可以得出結論

19、：相比之下,我們可以得出結論:殼體主要輻射區(qū)域包括:后殼,主減速器齒輪和后殼體。后殼是主要因素。所以任何減少噪音的措施必須針對后殼。</p><p>　　4. 后橋的結構修正 由于主要噪聲源一直是后殼蓋，因此本文通過十字柄和米字柄來控制后殼蓋的振動。這樣做是針對兩種頻率128.57Hz 和592Hz時哪種噪音達到最大值。</p><p>　　圖10 后橋殼蓋上的十字柄</p&

20、gt;<p>　　以十字柄為例,我們與之前(128.57Hz)的噪音相比較。我們標出以前的</p><p>　　顯示范圍。讓我們驚奇的是,后橋殼的最大聲壓由由96.45dB 變?yōu)?1.95 dB，大</p><p>　　概減少了4 dB。用米字柄的方法也出現(xiàn)了同樣的結果，后橋殼的最大聲壓由由</p><p>　　86.13dB變?yōu)?7.93 dB。&l

21、t;/p><p>　　圖11 后橋殼蓋上的米字柄</p><p><b>　　圖12 改善前</b></p><p>　　圖13 改善后 </p><p>　　五. 結論 再根據(jù)對對后橋殼振動的研究和噪聲的分析,本文確定了主要的噪聲源并改善能夠減少外力影響的結構,逐漸減少噪音輻射表面的輻射系數(shù)。同時

22、也會產(chǎn)</p><p>　　生更少的輻射噪聲能。</p><p>　　最后,我們可以推斷出一些結論</p><p>　　(1)后橋殼的背面時主要的噪聲源。</p><p>　　（2）車輛加速時分貝會增大。當在低檔的時候，低頻的鄭東將會更加劇烈。如果加速的話，最大噪聲的頻率將會變低，噪聲也將會更加尖聲。 （3）通過對柄的改進可有效減少噪

23、聲。但柄的數(shù)目的多少對減少震動和降低噪聲沒有太大的影響。</p><p><b>　　參考文獻 </b></p><p>　　[1]　S.P.Healy，Heppenstall，和D,Hodgetts，“車輛動力傳動系統(tǒng)振動的試驗研究”發(fā)動機和變速器的振動和噪音，機械工程師會議，1979年10月</p><p>　　[2] Sheng-Jiaw

24、 Hwang, Joseph L.Stout,Ching-Chung Ling “建模和分析的動力扭轉反應” SAE 980276</p><p>　　[3] Frank Fahy,噪音與結構振動輻射，瞬態(tài)響應，倫敦，學術出版社，1985年　　</p><p>　　[4] Akira Ishihara，用Hibert方法測量齒輪旋轉運動,JSAE，春季科學講座952號講義,1995年&l

25、t;/p><p>　　THE VIBRATION AND NOISE RESEARCH OF DRIVE AXLE</p><p>　　Lai Fei Deng ZhaoxiangZhang Jian</p><p>　　(State Key Laboratory of Mechanical Transmission, Chongqing University, C

26、hina)</p><p>　　Abstract: By building the whole assembled model of the rear axle, which is one of the main vibration and noise sources</p><p>　　on the power driveline of the vehicle, and then tak

27、e transient、harmonic and noise analysis. In this paper, Make use of CAD/CAE technology, and analyze the noise of a mini-vehicle’s rear axle, and then lodge the structure-improved idea. On the condition that not to interf

28、ere with the old structure and make big modifications, introducing the method of shank to modify the structure of the main noise radiation source. The simulation of the modified structure indicates the modified rear axle

29、 can redu</p><p>　　Key words: Drive axle Vibration Noise Boundary element Finite element</p><p>　　0.INTRODUCTION</p><p>　　The rear axle is the one of mainly vibration and

30、noise resources on the power train of the vehicle. It can produce the noise of gears and axletrees, and excite the vibration of shell to eradiate noise. In addition, as the rear axle is sustained by suspension, the rear

31、axle’s flexural and torsion vibrations and the bumpy road can also make big noise.</p><p>　　With the development of software、hardware、modern design and analysis technology, it is a trend way to solve the pr

32、oblems in experiment and test using the method of modern analysis technology. In this paper, it will use the simulation software ANSYS and ADAMS to analyze the dynamic characteristic and vibration force. Then use SYSNOIS

33、E to calculate the radiation noise due to the vibration of the exterior of rear axle. Base on it, forecast the noise of rear axle accurately and do some correspondin</p><p>　　1.MODELING THE REAR AXLE AND MA

34、KING SURE THE BOUNDARY CONDITIONS</p><p>　　The rear axle is made up of main reducing gear, differential mechanism, half shaft and rear axle housing. It delivers the engine torque passed by universal drive sh

35、aft to drive wheel that can slow the speed and increase the torque. It also sustains and protects the rear axle differential and half shaft etc, at the same time; it can fix the axial relative position of drive wheel and

36、 sustain the frame and other assemblies with slave axle. When moving, it can sustain the force and torque of road re</p><p>　　The main reducing gear of vehicle widely uses hypoid gears, which are bevel gear

37、wheels operate between cross shafts. As the axis lines of the small and big gears are not intersect, but offset some distance. When they are mating, they can roll in the circle direction and slide in the tine direction q

38、uite and smoothly. In order to reduce the vibration and noise, some other requirements must satisfied: </p><p>　　1) using large overlap coefficient to assure the number of mating gears is between 2 to 3 or

39、 more; </p><p>　　2) using the small number of teeth of the small gear to obtain large drive ratio and save space; </p><p>　　3) assembling exactly to make the mating surface exceed 50 percent.&

40、lt;/p><p>　　1.1 Partition of finite element mesh</p><p>　　The material of rear axle housing is forged iron and its density 7850 kg/m3, Young's modulus of elasticity 2.07e5Mpa, Poisson ratio 0.2

41、8, shear modulus 8.02e4,usingshell163element.Thematerial of drive gear is 20GrMnTi steel and its density 7800 kg/m3, Young's modulus of elasticity 2.1e5Mpa, Poisson ratio 0.3, shear modulus 8.02e4, using solid164 el

42、ement.</p><p>　　Fig 2 FEM but gears and drive axle housing</p><p>　　Fig 3 The set assembling of rear axle</p><p>　　1.2 The determination of boundary conditions</p><p&

43、gt;　　The boundary conditions of vibration analysis of rear axle include: the drive gear’s speed, the follower gear’s initial speed load, the constraint condition of the rear axle housing.</p><p>　　1.2.1The

44、deduction of drive gear’s speed</p><p>　　1)The type of drive wheel is 155R13 and the diameter of air-filled 576 mm.</p><p>　　2)Assuming the wheel’line speed is 90km/h, be equal to 25 m/s, so

45、the angular velocity is 86.8rad/s.</p><p>　　As the drive ratio of follower gear and drive gear is 41:8, so the angular velocity of drive gear is:</p><p>　　86.8*41/8=444.88rad/s. And the relation

46、al expression of input shaft and output shaft is:</p><p>　　w2 output angular velocity, w1 input constant angular velocity, a1 angle between input shaft and connection shaft, a2 angle between output shaft an

47、d connection shaft, φ1 is the rotate speed of input shaft. a1=a2=a=7.5, =444.88rad/s.</p><p>　　1.2.2The follower gear’s initial speed load</p><p>　　The vehicle’s speed can’t be 90km/h at the st

48、art point actually, but gradually increase into steady state. If the initial speed is not applied or applied inaccurately, the gears may generate great impact. Only when applying accurate initial speed load, the gears’ d

49、eform can be appropriate.</p><p>　　1.2.3The constraint condition of rear axle housing</p><p>　　The load that the housing bears comes from the impact when the gears mate. The impact is passed to

50、 the housing by the axle and bearing, and result in the housing’s vibration.</p><p>　　Fig 4 The constraint of rear axle housing</p><p>　　2.EXTRACTING THE DATE OF REAR AXLE TRANSIENT ANALYSIS&

51、lt;/p><p>　　The main purpose of transient analysis is to extract the load data of rear axle housing. The method to deal with the bearing and housing is node-pasted. So the nodes of exterior of surface (fig2 C,

52、D, E) are the points needed to analyze. All of the nodes amount to 552. According to the analysis of bearing axial and circumferential different nodes, we can find that the nodes’ response are almost the same. So when de

53、aling with the load data, we can regard the time-domain curve of the nodes of the </p><p>　　From the diagram below, we can find there is great vibration at frequencies followed as 71.43Hz, 128.57Hz, 200Hz an

54、d 271.43Hz. So the load data of the three different frequencies should be imported to SYSNOISE software for harmonic response analysis.(As the response of D and E are very much alike, so only the response of D is listed

55、below)</p><p>　　Fig 5 The frequency-domain response in 2000Hz at C</p><p>　　Fig 6 The frequency-domain response in 2000Hz at D</p><p>　　3.ANALYSIS OF REAR AXLE’S NOISE</p>

56、;<p>　　Firstly, we import the displacement result of the harmonic response and corresponding frequency. And then we can use Boundary Element Method (BEM) to solve the noise problem. The purpose is to find the mai

57、n noise source and to provide some proof for later improvement. Some documents have pointed out that the rear axle noise is resulted from the structural surface’s vibration, such as rear axle housing. Referred to the res

58、earch result of FEM, we know the housing’s vibration focus on housing rear</p><p>　　Fig 7 Field collocation</p><p>　　At frequency 128.57Hz, the result of sound pressure level (SPL) is below:&l

59、t;/p><p>　　Fig 8 The SPL of back housing</p><p>　　Fig 9 The SPL of up housing</p><p>　　From the figure, we can find the main noise source locate at main reducing gear shell and back

60、 housing. A great amount of faint yellow appears at these places and the SPL of these places is between 94.19db and 98.7db.</p><p>　　For the sake of comparison, we list the calculation result of all frequen

61、cies as follows:</p><p>　　By comparison, we can conclude: housing main radiation area nclude: back housing shell, main reducing gear shell and housing shell abdominal area. And back housing shell is the main

62、 area. So any measure to reduce the housing noise must aim at back housing shell.</p><p>　　4. MODIFIED STRUCTURE OF REAR AXLE</p><p>　　As the back housing shell is always the main source of rad

63、iation noise, this paper controls the housing shell’s vibration by cross shank and rice character shank. And it aims at two frequencies 128.57Hz and 592 Hz at which the noise is maximizing.</p><p>　　Fig10 T

64、he cross shank on rear axle housing’s cap</p><p>　　Fig11 The rice shank on rear axle housing’s cap</p><p>　　Taking cross shank for example, we compare the noise result with that before (at 128.

65、57Hz). And we set the indication range as before. To our surprise, the SPL maximum of the rear axle housing turns to 91.95 dB by 96.45dB, reducing about 4 dB. And the SPL maximum of the rear axle housing turns to 77.93 d

66、B by 86.13 dB, the same result as the method of rice character shank.</p><p>　　5.CONCLUSIONS</p><p>　　Based on the research of the rear axle housing’s vibration and noise analysis, this paper i

67、dentifies the main radiation noise resource and improves the structure that reduces the response of the housing to exciting force, diminishing the sound radiation coefficient of the radiation surface of noise. And the fe

68、wer radiation noise energy will be produced when at the same exciting condition. Finally some conclusions can be deduced:</p><p>　　(1) The back area of the rear axle housing shell is the main radiation noise

69、 resource place;</p><p>　　(2) The SPL will increase when the speed of vehicle arises. And when the speed is at the low range, the vibration of low frequency of housing will sharp. If the speed increases, the

70、 frequency of the maximum noise will slow down and the noise will be more acute.</p><p>　　(3) By the method of shank, the noise can be reduced effectively. But the density of the shank plays a little role in

71、 slowing down the vibration and reducing the noise.</p><p><b>　　Reference</b></p><p>　　[1] S.P.Healy, T.Heppenstall, and D,Hodgetts, “An experimental study of vehicle driveline v

72、ibrations” Noise and Vibration of Engines and Transmissions, I Mech E Conferences,1979-10</p><p>　　[2] Sheng-Jiaw Hwang, Joseph L.Stout,Ching-Chung Ling “Modeling and Analysis of Powertrain Torsional Resp

73、onse” SAE 980276</p><p>　　[3] Frank Fahy, Sound and Structural Vibration Radiation, Transmission and Response, London: Academic Press, 1985</p><p>　　[4] Akira Ishihara. Measurement of Rota