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轉(zhuǎn)矩當量轉(zhuǎn)矩 ()當量彎矩圖如圖311圖311 當量彎矩圖校核軸徑 ()由此可知此軸的設計滿足強度的要求。用相同的方法驗證從動軸2,也滿足強度的要求 數(shù)據(jù)采集及計算機處理程序 測試系統(tǒng)整個測試系統(tǒng)由穩(wěn)態(tài)激振裝置、BSH柱式荷重傳感器、放大電路、PCI1710數(shù)據(jù)采集卡、計算機和打印機組成如圖312。圖312 系統(tǒng)框圖具體測試過程為,首先根據(jù)路面的構成選擇激振頭的型號。BSH柱式荷重傳感器其量程為:,將壓力信號經(jīng)放大電路后,轉(zhuǎn)換成177。5V標準電壓信號,再經(jīng)過PCI1710數(shù)據(jù)采集卡的8路雙端A/D轉(zhuǎn)換成數(shù)字信號,計算機按一定的采樣頻率進行采樣,把數(shù)據(jù)儲存起來,進行分析處理,并經(jīng)過軟件把檢驗結果顯示和打印出來如圖313。圖313 激振力時域波形及其頻譜 數(shù)據(jù)分析 穩(wěn)態(tài)激振裝置的設計參數(shù)為激振力5kN、激振頻率30Hz,上述的理論計算基本滿足設計要求。本試驗是驗證設計的正確性和該方法的實用性。 (a)和(b)是使 (a) (b)圖314 激振力時域波形及其頻譜用100mm激振頭分別激打瀝青路面和水泥路面的時域波形和頻域波形。從時域波形上看激振力的波動范圍大體在5kN15kN之間;從頻域波形上看系統(tǒng)的頻率主要集中在30Hz左右,其次是50Hz的交流電頻率,其它高頻成分是齒輪在嚙合過程中的撞擊頻率。從試驗結果看,激振力的幅值集中在5kN以上,最大峰值達到15kN。究其產(chǎn)生原因,是設計的激振力參數(shù)是一個理論靜態(tài)值,而測量過程所測得的是瞬時動態(tài)值。這里既包括偏心輪產(chǎn)生的激振力,又包括偏心輪帶動電機箱和相應附件對路面或試樣 所產(chǎn)生的慣性沖擊力。因此測量結果不僅和靜態(tài)激振力有關,有和動態(tài)沖擊力有關,即和被測路面的材質(zhì)有關。當被測路面的材質(zhì)較軟時,激振頭激打路面被彈起的高度較小,所產(chǎn)生的動態(tài)沖擊力就小。表現(xiàn)在測量結果其幅值響應較小,約在5kN11kN之間,如圖314(a)。反之,被測路面的材質(zhì)較硬時,激振頭激打路面被彈起的高度大,所產(chǎn)生的動態(tài)沖擊力就大。表現(xiàn)在測量結果其幅值響應就大,約在5kN15kN之間,如圖314(b)。如此測量結果基本滿足實際情況。 激振力的頻率在頻域波形可以清晰地看出,波動的原因是由于電動機的載荷不均和電網(wǎng)不穩(wěn)所造成。不會對檢測質(zhì)量造成影響。 數(shù)據(jù)處理程序 根據(jù)上述理論。數(shù)據(jù)處理及顯示和人機界面采用自己開發(fā)的應用軟件。是利用板卡廠家提供的動態(tài)連接庫文件(.DLL文件)來完成的,調(diào)用了PCI1710數(shù)據(jù)采集卡提供的專用函數(shù)。采用這種方法,既提高了軟件的可靠性,也大大縮短了系統(tǒng)和軟件的開發(fā)周期。主要功能有:人機界面、設置采樣點數(shù)、采樣數(shù)率、數(shù)據(jù)采集分析存儲、顯示和打印等子程序。在實際使用中取得良好效果。結 論隨著現(xiàn)代技術的發(fā)展,激振器的需求是越來越多。這次畢業(yè)設計選擇新型的激振器是因為我覺得它更比較使用,是給很好的實踐機會,尤其是在加工出成品后,使我更相信知識的應用是多么的關鍵和實際。雖然本次設計依然存在著不足,可讓我學到了很多東西。 在為期20周的設計過程中,通過老師的引導和自己收集資料,初步的了解了激振器的相關知識;比較系統(tǒng)的學習了激振器設計的流程,包括偏心塊的選擇、偏心塊的計算、激振器的各個部件的設計。這次激振器設計的整個過程都是在計算機的輔助(CAD)下完成的,比以往的手工畫圖更方便快捷。它使我深深的體會到:在掌握好專業(yè)知識的同時,在計算機這個平臺上對機械產(chǎn)品進行設計、裝配、分析等將是機械行業(yè)發(fā)展的一個必然趨勢,兩者缺一不可。這次畢業(yè)設計也讓我了解到了一些企業(yè)產(chǎn)品設計和生產(chǎn)的過程,使我大開眼界,為以后走上工作崗位奠定了扎實的基礎。與此同時,由于實踐經(jīng)驗的缺乏,在激振器的設計過程中可能會出現(xiàn)一些錯誤,懇請各位老師同學批評和指正。致 謝在此次畢業(yè)設計中我所選擇的課題是激振器的設計,在這之前我關于激振器的知識是一片空白,我能夠順利完成這個設計,都是我的導師時獻江老師的大力幫助和精心指導下的結果。并在設計中學會了零件的設計,并對Autou CAD軟件的運用更加熟練,還學到許多新的功能,得到了這個很好的鍛煉自己的機會。在此對時獻江老師表示衷心的感謝,同時感謝在設計中給予我鼓勵和幫助同學。參考文獻1 (日)谷口修主編。,19832 吳仁智,黃海。振動壓路機性能的計算機仿真計算方法。中國期刊, 1995年07期 3 ,19994 ,19985 ,19906 ,20027 ,19988 周臨震, , 20069 10 lastics Engineering ed. The Society of The Plastics Industry Inc 1960 11 Nelson R B. Simplified calculation of eigenvector derivatives .AI AA ,14(9)1201120512 Zarghamee M. S. Optimum frequency of structures .AI AA Journal, 1968, 6(6) :749750 . 13 Ramana G. Structural optimization with frequency constraints a review AI AA Journal, 1993, 31(12) :22962303 . 附錄Forcing of Unbalanced Vibration Exciters in the Drive System of Drilling ShakersThe possibility of increasing the amplitude of the vibration acceleration of seriesproduced shakers from 40–50 to 75–80m/sec2 for the purpose of improving their carrying capacity is examined. In refining existing methods for the cleaning of drilling muds, a new generation of vibro shakers has been developed with an increased carrying capacity. The American firms Swaco and Derrick have built drilling shakers in which the amplitude of vibration acceleration of the frame is 7–8 g. In the FloLine series of shakers produced by the Derrick Corp. for example, the amplitude a of vibro acceleration is increased to 70–73 m/sec2(for conventional shakers, a = 40–50 m/sec2) due to the use of special unbalanced vibration exciters (UVE).Let us examine the possibility of increasing the amplitude of the vibro acceleration of domestic seriesproduced SV1LM shakers to 75–80 m/sec2.The amplitude of vibro acceleration is determined from the formula [2] (1)where m is the unbalanced mass in kg, e is the mass eccentricity of the unbalanced mass in m, mΣ is the mass of the vibrating frame as a unit in kg, and w is the angular velocity of the UVE in rad/sec.It is apparent from expression (1) that the static moment of the unbalanced mass me, or the angular velocity of the UVE must be increased in order to raise the amplitude of vibro acceleration. In any case, the radial load R on each support of the rotor of the electric motor is appreciably increased: R = mεω2/2.In forcing the UVE, therefore, it is necessary to ensure a given longevity L0 (h) for the bearing supports [3]: (2)where C and P are the dynamic loadcarrying capacity and equivalent bearing load, respectively, in N。 q is an exponent。 and n is the rotational speed of the UVE shaft in rpm.The UVE of the SV1LM shaker [4] are equipped with two No. 42312 roller bearings, the axis of rotation of which is horizontal。 the equivalent load is therefore determined only by the radial load on the bearings.According to remendations given by Anur’ev [3], q = and the equivalent load (3)for the existing loading diagram.Fig. 1. Dependence of limiting amplitude alim of vibro acceleration on angular velocity ω of UVE: 1) No. 7612 bearing。 2) No. 7312 bearing。 3) No. 42312 bearing, used in SV1LM shaker.Transforming the rotational speed n of the UVE shaft to an angular velocity ω = 2πn/60, and substituting it and expression (3) in Eq. (2), we obtain the functional relationship between the maximum allowable static moment of the UVE mass (mε)max and its