發(fā)布時(shí)間：2018-01-25 04:25

  本文關(guān)鍵詞： 陶瓷CBN砂輪 回轉(zhuǎn)試驗(yàn)機(jī) 主軸 有限元 聲發(fā)射　出處：《鄭州大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：陶瓷CBN(Cubic Boron Nitride立方氮化硼)砂輪是超硬材料及制品行業(yè)最具代表性產(chǎn)品,是磨削加工領(lǐng)域中的一種高性能磨具,具有高速、高效、高精度、低污染等優(yōu)點(diǎn)。陶瓷CBN砂輪的主要性能檢測(cè)是回轉(zhuǎn)強(qiáng)度試驗(yàn),因?yàn)樯拜喸谧鳂I(yè)過程中一旦破碎其后果是不可想象的。高速回轉(zhuǎn)試驗(yàn)機(jī)應(yīng)用于回轉(zhuǎn)類砂輪的回轉(zhuǎn)強(qiáng)度試驗(yàn),從而檢驗(yàn)砂輪在規(guī)定試驗(yàn)條件下的回轉(zhuǎn)強(qiáng)度。目前我國(guó)的超硬材料磨具高速回轉(zhuǎn)試驗(yàn)檢測(cè)設(shè)備還處于相對(duì)滯后的狀態(tài),主要原因是主軸系統(tǒng)方面有效負(fù)載能力低、轉(zhuǎn)速上不去,控制系統(tǒng)方面現(xiàn)有的砂輪破碎識(shí)別方法不能滿足超硬類砂輪破碎信號(hào)識(shí)別。本課題在深度分析陶瓷CBN砂輪回轉(zhuǎn)試驗(yàn)基本原理和功能要求的基礎(chǔ)上,從機(jī)械主軸系統(tǒng)自主設(shè)計(jì)、砂輪破碎信號(hào)檢測(cè)入手,對(duì)陶瓷CBN砂輪高速回轉(zhuǎn)試驗(yàn)機(jī)關(guān)鍵技術(shù)進(jìn)行了研究�；谧灾髟O(shè)計(jì)的主軸系統(tǒng),本文對(duì)主軸軸承選用、安裝、軸承剛度進(jìn)行了深入研究。應(yīng)用赫茲理論計(jì)算出預(yù)緊力,采用MATLAB編程軟件驗(yàn)證了增大預(yù)緊力不僅可以提高軸承的剛度,還能提高主軸的靜態(tài)剛度和臨界轉(zhuǎn)速;得出主軸轉(zhuǎn)速提高會(huì)使軸承徑向剛度減小、軸向剛度增大,預(yù)緊力和軸承剛度存在一個(gè)平衡點(diǎn)的結(jié)論。采用有限元分析理論,以ANSYS軟件為基礎(chǔ),建立了主軸模型,分別對(duì)主軸靜、動(dòng)態(tài)特性進(jìn)行了研究,分析了主軸剛度和應(yīng)力特點(diǎn),確定了主軸固有頻率、主要振型和共振頻率,得到了主軸最小動(dòng)剛度頻率、主軸諧響應(yīng)固有變形量和固有頻率特征值,驗(yàn)證了主軸系統(tǒng)結(jié)構(gòu)設(shè)計(jì)的合理性。為了提高砂輪破碎信號(hào)識(shí)別的精準(zhǔn)性,本文對(duì)陶瓷CBN砂輪的破碎特征、振動(dòng)機(jī)理、信號(hào)特點(diǎn)進(jìn)行了深入研究,結(jié)合聲發(fā)射信號(hào)原理、特點(diǎn)、處理方法,以普通砂輪聲發(fā)射特征為基礎(chǔ),得到了砂輪破碎具有非高斯信號(hào)特征。依據(jù)設(shè)計(jì)的實(shí)驗(yàn)方案,通過在自主設(shè)計(jì)主軸系統(tǒng)上進(jìn)行陶瓷CBN砂輪回轉(zhuǎn)實(shí)驗(yàn),采用AE信號(hào)時(shí)域分析方法,研究了砂輪破碎后與破碎前相比聲發(fā)射信號(hào)的電壓幅值圖、能量圖、波形圖,結(jié)果表明AE信號(hào)特征均發(fā)生明顯變化,得到了AE信號(hào)波形由平穩(wěn)連續(xù)信號(hào)變成突發(fā)式連續(xù)信號(hào)的結(jié)論。運(yùn)用FFT運(yùn)算法則、小波變換,驗(yàn)證了AE信號(hào)符合Symlet小波函數(shù)對(duì)稱性,得出了陶瓷CBN砂輪破碎后AE信號(hào)向高頻區(qū)發(fā)展的變化特征,表明陶瓷CBN砂輪破碎后會(huì)產(chǎn)生一個(gè)高頻電壓信號(hào)的結(jié)論。研究結(jié)果表明:自主設(shè)計(jì)的主軸系統(tǒng)穩(wěn)定性達(dá)到預(yù)期效果;聲發(fā)射技術(shù)優(yōu)于目前常用的光電法、音量法和振動(dòng)法,更適合用于砂輪回轉(zhuǎn)試驗(yàn)破碎識(shí)別領(lǐng)域。
[Abstract]:Ceramic CBN(Cubic Boron Nitride cubic boron nitride (CBN) grinding wheel is the most representative product of superhard materials and products industry, and it is a kind of high performance abrasive tool in grinding field. It has the advantages of high speed, high efficiency, high precision and low pollution. The main performance test of ceramic CBN grinding wheel is rotary strength test. It is unthinkable that the grinding wheel is broken once it is broken in the process of operation. The high-speed rotary testing machine is applied to the rotary strength test of the rotary grinding wheel. In order to test the rotational strength of the grinding wheel under the specified test conditions, at present, the high speed rotary testing equipment of the super hard material grinding tools in our country is still in the state of relative lag. The main reason is the low payload capacity of the spindle system, the speed of the system does not go. The existing grinding wheel breaking identification methods in control system can not meet the breaking signal recognition of superhard grinding wheel. This topic is based on the in-depth analysis of the basic principle and functional requirements of ceramic CBN wheel rotary test. Starting with the independent design of the mechanical spindle system and the detection of the grinding wheel breaking signal, the key technology of the ceramic CBN grinding wheel high-speed rotary testing machine is studied. Based on the self-designed spindle system, the spindle bearing is selected in this paper. The stiffness of bearing is studied deeply, the preload is calculated by Hertz theory, and the MATLAB software is used to verify that increasing preload can not only improve the stiffness of bearing. It can also improve the static stiffness and critical speed of the spindle. It is concluded that the increase of spindle speed will decrease the radial stiffness and increase the axial stiffness of bearing, and there is a balance point between preload force and bearing stiffness. The theory of finite element analysis is adopted and based on ANSYS software. The static and dynamic characteristics of the spindle are studied, the stiffness and stress characteristics of the spindle are analyzed, and the natural frequency, main mode and resonance frequency of the spindle are determined. The minimum dynamic stiffness frequency of the spindle, the intrinsic deformation of the spindle harmonic response and the eigenvalue of the natural frequency are obtained, which verifies the rationality of the structural design of the spindle system, in order to improve the accuracy of the grinding wheel breaking signal recognition. In this paper, the crushing characteristics, vibration mechanism and signal characteristics of ceramic CBN grinding wheel are studied in depth. Combined with the acoustic emission signal principle, characteristics, processing methods, based on the ordinary grinding wheel acoustic emission characteristics as the basis. According to the designed experimental scheme, the rotary experiment of ceramic CBN grinding wheel was carried out on the self-designed spindle system, and the time-domain analysis method of AE signal was adopted. The voltage amplitude diagram, energy diagram and waveform diagram of acoustic emission signal after grinding wheel breaking are studied. The results show that the characteristics of AE signal are obviously changed. The conclusion that AE signal waveform changes from stationary continuous signal to burst continuous signal is obtained. The FFT algorithm and wavelet transform are used to verify that AE signal conforms to the symmetry of Symlet wavelet function. The characteristics of AE signal development to high frequency region after crushing ceramic CBN grinding wheel were obtained. The results show that the ceramic CBN grinding wheel will produce a high frequency voltage signal after crushing. The results show that the stability of the self-designed spindle system achieves the desired effect. The acoustic emission technique is better than the photoelectric method, volume method and vibration method, and is more suitable for grinding wheel rotary test crushing identification.
【學(xué)位授予單位】：鄭州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG743;TH873

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1 王永峰;陶瓷CBN砂輪高速回轉(zhuǎn)試驗(yàn)機(jī)關(guān)鍵技術(shù)研究[D];鄭州大學(xué);2017年

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本文編號(hào)：1461977