本文關(guān)鍵詞： 高精機(jī)床 熱力耦合 數(shù)值模擬 接觸剛度 進(jìn)給單元 動(dòng)態(tài)精度　出處：《哈爾濱工業(yè)大學(xué)》2016年博士論文　論文類(lèi)型：學(xué)位論文

【摘要】：高速、高精數(shù)控機(jī)床是影響和制約電子制造業(yè)水平和電子信息產(chǎn)業(yè)基礎(chǔ)配套能力的重要因素。近年來(lái),隨著信息、通訊、醫(yī)療、航空航天等領(lǐng)域的電子產(chǎn)品向高功能、高密度及高可靠性發(fā)展,對(duì)數(shù)控機(jī)床加工精度、效率及穩(wěn)定性提出了更高要求。熱誤差是影響高精機(jī)床動(dòng)態(tài)加工精度的決定性因素,占全部加工誤差的70%。因此,開(kāi)展工程熱誤差機(jī)理的研究對(duì)于解決高精機(jī)床普遍存在熱穩(wěn)定性差的技術(shù)瓶頸具有重要意義。整機(jī)熱動(dòng)態(tài)性能是溫度場(chǎng)在結(jié)構(gòu)上產(chǎn)生的復(fù)雜熱應(yīng)力、非線(xiàn)性變形及構(gòu)件間熱力耦合效應(yīng)的綜合體現(xiàn),因此不能孤立研究局部系統(tǒng)的熱現(xiàn)象。本文從全局角度分析了機(jī)床系統(tǒng)內(nèi)部結(jié)構(gòu)單元及整機(jī)在熱力耦合效應(yīng)下的靜、動(dòng)態(tài)精度特性及演變規(guī)律,主要內(nèi)容如下:直線(xiàn)滾動(dòng)導(dǎo)軌非線(xiàn)性剛度分析�；贖ertz接觸理論,考慮接觸體彈性變形及預(yù)緊效應(yīng)建立了導(dǎo)軌初始剛度模型,量化了上、下滾道初始剛度隨外載呈相反趨勢(shì)的非線(xiàn)性變化特性。通過(guò)對(duì)導(dǎo)軌滾珠差動(dòng)滑動(dòng)、彈性滯后及自旋運(yùn)動(dòng)的摩擦能解析,計(jì)算了滾動(dòng)界面的等效熱源強(qiáng)度,并基于Achard磨損理論建立了導(dǎo)軌接觸界面磨損量計(jì)算模型�；趯�(dǎo)軌熱力耦合數(shù)值模擬及磨損深度解析建立了最終剛度模型,結(jié)果顯示,上、下滾道接觸剛度在摩擦熱傳遞、熱彈接觸變形及磨損綜合作用下隨行程而呈現(xiàn)不同程度的非線(xiàn)性遞減。通過(guò)LMS振動(dòng)測(cè)試完成剛度模型的頻域驗(yàn)證,成功探測(cè)到導(dǎo)軌由于接觸剛度下降剛體模態(tài)由(2.36-6.58)k Hz遷移至(2.05-5.66)k Hz,并基于提出的剛度模型建立了更為精確的導(dǎo)軌剛體模態(tài)頻率解析式,實(shí)測(cè)頻率與解析值最大誤差為15.2%。同時(shí),結(jié)果表明,摩擦熱和磨損效應(yīng)對(duì)導(dǎo)軌剛度變化的影響具有時(shí)序性。將熱影響研究拓展至整機(jī)基礎(chǔ)結(jié)構(gòu),分析了環(huán)境熱波動(dòng)下新型礦物鑄件材料機(jī)架的熱力學(xué)性能及結(jié)構(gòu)靜態(tài)精度。通過(guò)平面度測(cè)試和線(xiàn)性模態(tài)分析驗(yàn)證了此材料替代傳統(tǒng)材料應(yīng)用于精密機(jī)床的可靠性。結(jié)果表明,礦物鑄件結(jié)構(gòu)靜態(tài)剛度可滿(mǎn)足精密機(jī)床大型基礎(chǔ)構(gòu)件50μm平面度的精度要求,其動(dòng)力學(xué)特性?xún)?yōu)于鑄鐵,模態(tài)特性略遜于天然花崗石,低階自然振動(dòng)頻率高于90Hz,保證了其在系統(tǒng)典型激振頻率下的動(dòng)力學(xué)穩(wěn)定性�；谟邢拊ㄍ茖�(dǎo)了礦物鑄件結(jié)構(gòu)溫度場(chǎng)解析方程,通過(guò)熱傳遞及熱力耦合數(shù)值模擬結(jié)合激光干涉儀測(cè)試,量化了礦物鑄件機(jī)架在外部熱源波動(dòng)、表面對(duì)流及熱力耦合效應(yīng)下的非線(xiàn)性變形機(jī)理,揭示了恒溫控制對(duì)保證大型構(gòu)件在環(huán)境熱波動(dòng)下結(jié)構(gòu)精度的至關(guān)重要性。進(jìn)一步將熱研究拓展至進(jìn)給系統(tǒng),量化高精平臺(tái)在復(fù)雜熱環(huán)境下的熱力學(xué)行為及動(dòng)態(tài)精度。通過(guò)建立結(jié)合部混合支撐下進(jìn)給系統(tǒng)動(dòng)力學(xué)微分方程,揭示了重心驅(qū)動(dòng)的重要性。為避免孤立平臺(tái)結(jié)構(gòu),建立了包含完整進(jìn)給系統(tǒng)的熱力耦合數(shù)值模型,考慮了電機(jī)熱、導(dǎo)軌摩擦熱及環(huán)境熱波動(dòng)。通過(guò)動(dòng)力學(xué)沖擊分析量化了平臺(tái)在熱力耦合作用下的非線(xiàn)性變形及動(dòng)態(tài)偏擺機(jī)制,并通過(guò)激光干涉儀進(jìn)行了驗(yàn)證。結(jié)果顯示,平臺(tái)動(dòng)態(tài)誤差隨環(huán)境溫升非線(xiàn)性遞增,溫變4°C-8°C,平均偏擺誤差達(dá)5.12-10.67μm/m,且保證高精平臺(tái)理想動(dòng)態(tài)精度的溫度波動(dòng)上限為4℃。同時(shí),從電機(jī)多通道溫度測(cè)試和導(dǎo)軌熱通量解析發(fā)現(xiàn),外部環(huán)境熱波動(dòng)是影響進(jìn)給系統(tǒng)動(dòng)態(tài)精度的最關(guān)鍵熱源,而非系統(tǒng)內(nèi)部熱源。從全局角度定量研究了高精機(jī)床在真實(shí)工況下加工精度的變化機(jī)理。通過(guò)整機(jī)熱力耦合建模及求解,量化了系統(tǒng)在綜合熱源波動(dòng)、接觸熱阻及熱力耦合效應(yīng)下的溫度場(chǎng)分布及結(jié)構(gòu)的非線(xiàn)性變形。結(jié)果表明,環(huán)境溫升5℃,平臺(tái)呈二階彎曲變形,顯著影響其動(dòng)態(tài)精度�；谶\(yùn)動(dòng)結(jié)構(gòu)的動(dòng)力學(xué)沖擊熱力耦合數(shù)值模擬,得到了TCP(刀具中心)點(diǎn)在內(nèi)、外部熱源及熱力耦合效應(yīng)下的動(dòng)態(tài)位置精度。數(shù)值和測(cè)試結(jié)果一致表明,孔位精度隨外界環(huán)境溫升而衰減,溫升5℃時(shí),部分軸位已經(jīng)無(wú)法達(dá)到25.4μm的孔位精度要求。通過(guò)微孔鉆實(shí)驗(yàn)進(jìn)一步分析了不同熱環(huán)境下機(jī)床動(dòng)態(tài)鉆孔精度的CPK(制程能力指數(shù))值及變化規(guī)律,再次揭示了環(huán)境熱波動(dòng)對(duì)其自身加工精度的極端重要性。
[Abstract]:High speed, high precision CNC machine tool is an important factor affecting and restricting the level of electronic manufacturing industry and electronic information industry base supporting capacity. In recent years, along with the information, communications, medical, aerospace and other fields of electronic products to high function, high density and high reliability, the machining accuracy of NC machine tool, put forward higher requirements the efficiency and stability. The thermal error is the decisive factor affecting the dynamic high precision machining precision of the machine tool, the total error of 70%. therefore, to carry out research on engineering thermal error mechanism to solve the high precision machine tool exists is important technical bottleneck of poor thermal stability. The thermal and dynamic properties are complex temperature field in the structure of production the stress, comprehensive reflection of nonlinear deformation and thermo mechanical coupling effect between components, so the thermal phenomena cannot be isolated to study local system. This paper analyzes the machine system from a global perspective The internal structure of the unit and in the thermal coupling effect under static and dynamic accuracy characteristics and evolution, the main contents are as follows: the analysis of nonlinear stiffness of linear rolling guide. Based on Hertz contact theory, considering the contact elastic deformation and preload effect established rail initial stiffness model, quantization, initial stiffness of raceway the nonlinear change characteristics with loads. The contrary tendency ball differential sliding friction, elastic hysteresis and spin energy analysis, equivalent heat intensity calculation of the rolling interface, and Achard wear theory calculation model was established based on wear of rail contact interface. Numerical simulation and thermodynamic coupling rail wear depth analysis was established the final results show that the stiffness model based on lower raceway contact stiffness transfer in friction heat, thermal elastic contact deformation and abrasion with different degree of stroke The nonlinear decreasing vibration test by LMS. Complete the verification frequency stiffness model, successfully detected guide because the contact stiffness decreased by rigid mode (2.36-6.58) k Hz (2.05-5.66) k migrated to Hz, and the stiffness model is put forward based on a more rigid guide mode frequency analytical precision, the measured frequency with the analytical value of the maximum error is 15.2%. at the same time, the results show that the effect of friction heat and wear effect of track stiffness change with time. The effect of thermal expansion to the basic structure, the new type of mineral casting material under dynamic thermal environment frame thermodynamic properties and structural static analysis. The reliability of precision materials to replace conventional materials used in the precision machine tool is verified by the flatness measurement and linear modal analysis. The results show that the mineral casting structure static stiffness can meet the precision machine tool large foundation member 50 m flatness The precision, the dynamic characteristics of the modal characteristics were better than cast iron, natural granite, low order natural vibration frequency is higher than 90Hz, which in a typical vibration system under dynamic stability. The temperature field of mineral casting structure based on the finite element method is deduced by means of heat transfer and thermal mechanical coupling numerical simulation combined with laser interferometer testing, to quantify the mineral casting frame in external heat wave, the deformation mechanism of nonlinear surface convection and thermal coupling effect, reveals the temperature control to ensure the vital importance of large dynamic structure in the environment. The accuracy of thermal wave will further expand to the hot research feed system, thermodynamic behavior quantitative high precision platform in complex thermal environment and the dynamic precision. Dynamic differential equation of mixed feed system supported by establishing a connection, and reveals the importance of gravity driven. Avoid isolated platform structure, established the thermal mechanical coupling numerical model including complete feed system, considering the motor heat, friction heat and thermal environment fluctuation. Through dynamic impact analysis to quantify the nonlinear deformation and dynamic platform under thermo mechanical coupling deflection mechanism, and through the laser interferometer was verified. The results show that the platform the dynamic error with the environment temperature increasing, temperature of 4 DEG C-8 DEG C, the average yaw error reached 5.12-10.67 mu m/m, and ensure the maximum temperature fluctuation and high precision platform ideal dynamic accuracy is 4 DEG C. At the same time, found from the motor multi-channel temperature testing and guide heat flux analysis, thermal fluctuation is the external environment the pivotal effect of the drive system dynamic accuracy, rather than the internal heat source system. The change mechanism of processing in the real working condition of high precision precision machine tool research from a global perspective. Through the quantitative thermodynamic Ou Hejian Model and solution, quantitative fluctuation of system in heat deformation, thermal contact resistance and thermal coupling effect under the nonlinear temperature field distribution and structure. The results show that the environment temperature is 5 DEG C, platform two order bending deformation, significantly affect the dynamic precision. Dynamic motion of structure impact thermo mechanical coupled numerical simulation based on the obtained TCP (tool center point), the dynamic position precision of external heat source and thermal coupling effect. The numerical and test results show that the accuracy of hole position with the external environment temperature rise and decay, the temperature rise of 5 degrees, some axis has been unable to reach 25.4 mu m. Through the micro hole drilling hole position accuracy the further analysis of the machine tool dynamic precision drilling in different thermal environments CPK (process capability index) value and change the regulation, once again reveals the extreme importance of environmental thermal fluctuations on its machining precision.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TG502.13

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