發(fā)布時間：2018-04-12 11:11

  本文選題：角接觸球軸承 + 動態(tài)精度　； 參考：《河南科技大學(xué)》2015年碩士論文

【摘要】：數(shù)控機床是高端裝備制造業(yè)的工作母機,隨著科學(xué)技術(shù)的發(fā)展,機床正向著高精度化、高速化的方向發(fā)展。機床主軸系統(tǒng)作為整個機床的核心部分,其動態(tài)性能的好壞直接影響著機床的加工精度,軸承作為電主軸系統(tǒng)的重要支承部件,軸承的動態(tài)精度及其性能直接影響著主軸系統(tǒng)的穩(wěn)定性和可靠性。為了提高高檔數(shù)控機床的加工精度,需要對數(shù)控機床主軸軸承的動態(tài)精度進(jìn)行分析研究。本文主要圍繞機床主軸常用的角接觸球軸承進(jìn)行了動態(tài)精度研究,運用赫茲理論、套圈控制理論等滾動軸承的基本理論知識,以及滾動軸承動力學(xué)分析方法,對軸承的運動狀態(tài)進(jìn)行了分析,建立滾動軸承的力學(xué)模型,對軸承的載荷分布與變形之間的關(guān)系進(jìn)行了研究,主要研究了預(yù)緊力和初始接觸角對軸承變形的影響,分析了摩擦力矩產(chǎn)生的機理,推導(dǎo)了摩擦力矩和旋滾比的計算公式,研究了軸承的聯(lián)合載荷、轉(zhuǎn)速對軸承旋滾比的影響,探討了這些參數(shù)對軸承磨損及動態(tài)精度的影響。通過分析計算得出軸承的原始接觸角、曲率之間的關(guān)系;推導(dǎo)了滾動軸承軸向、徑向位移變形公式,隨著轉(zhuǎn)速的升高,軸承的徑向變形逐漸增大,軸承的軸向變形則減小,在同一轉(zhuǎn)速時滾動軸承的徑向變形量隨著預(yù)緊力的變大而逐漸減小,軸向變形量隨著預(yù)緊力的變大而變大;當(dāng)滾動軸承的初始接觸角較大時,軸承的徑向變形量較大,徑向剛度較小,軸承軸向變形量較小,其剛度較大。通過比較發(fā)現(xiàn),軸承的旋滾比會隨著轉(zhuǎn)速的升高而逐漸增大;在載荷作用下,增加軸向力可以降低軸承的旋滾比。大的旋滾比將會加劇軸承磨損生熱,不利于軸承精度的保持。在Hertz接觸理論和軸承運動學(xué)的基礎(chǔ)上,推導(dǎo)了滾動軸承非線性軸承力,建立了滾動軸承非線性振動的分析模型,分析了軸承的振動特性,研究了轉(zhuǎn)速、阻尼、徑向力及滾動體數(shù)目對軸承系統(tǒng)振動特性的影響,結(jié)果顯示軸承系統(tǒng)的響應(yīng)具有周期和非周期形式,增加滾動體個數(shù)和減小徑向載荷,有利于提高軸承系統(tǒng)的動態(tài)精度。通過設(shè)計合理的結(jié)構(gòu)參數(shù)和工況參數(shù),保證系統(tǒng)的穩(wěn)定性,提高軸承系統(tǒng)的動態(tài)精度。最后對某型數(shù)控機床主軸系統(tǒng)進(jìn)行了試驗研究。
[Abstract]:With the development of science and technology, CNC machine tool is developing towards high precision and high speed.The spindle system of the machine tool is the core part of the whole machine tool, and its dynamic performance directly affects the machining accuracy of the machine tool. Bearing is an important supporting part of the motorized spindle system.Bearing dynamic accuracy and performance directly affect the stability and reliability of spindle system.In order to improve the machining accuracy of high-grade NC machine tools, it is necessary to analyze and study the dynamic accuracy of spindle bearings of NC machine tools.In this paper, the dynamic precision of the angular contact ball bearings commonly used in machine tool spindle is studied, and the basic theoretical knowledge of rolling bearings, such as Hertz theory and ring control theory, as well as the dynamic analysis method of rolling bearings are used.The motion state of the bearing is analyzed, the mechanical model of the rolling bearing is established, the relationship between the load distribution and the deformation of the bearing is studied, and the influence of the preloading force and the initial contact angle on the deformation of the bearing is mainly studied.The mechanism of friction torque is analyzed, the formula of friction moment and rotation ratio is deduced, the influence of bearing joint load and rotational speed on bearing rotation ratio is studied, and the influence of these parameters on bearing wear and dynamic precision is discussed.The relations between the original contact angle and curvature of the bearing are obtained by analyzing and calculating. The axial and radial displacement deformation formulas of the rolling bearing are derived. With the increase of the rotational speed, the radial deformation of the bearing increases gradually, and the axial deformation of the bearing decreases.At the same speed, the radial deformation of the rolling bearing decreases with the increase of the pretightening force, and the axial deformation increases with the increase of the preloading force, and when the initial contact angle of the rolling bearing is large, the radial deformation of the bearing is larger.The radial stiffness is smaller, the axial deformation is smaller, and the stiffness is larger.By comparison, it is found that the rolling ratio of bearings increases with the increase of rotational speed, and the axial force can decrease the ratio of rotation to roll under load.Large roll ratio will increase the bearing wear heat, which is not conducive to the bearing accuracy.On the basis of Hertz contact theory and bearing kinematics, the nonlinear bearing force of rolling bearing is deduced, the analysis model of nonlinear vibration of rolling bearing is established, the vibration characteristic of bearing is analyzed, and the speed and damping are studied.The effects of radial force and the number of rolling bodies on the vibration characteristics of bearing system are discussed. The results show that the response of bearing system has periodic and aperiodic forms. Increasing the number of rolling bodies and reducing radial load can improve the dynamic accuracy of bearing system.The stability of the system is ensured and the dynamic precision of the bearing system is improved by designing reasonable structure parameters and working conditions parameters.Finally, the spindle system of a numerical control machine tool is tested and studied.
【學(xué)位授予單位】：河南科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG659

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本文編號：1739486