軸承預(yù)緊力對(duì)滾珠絲杠系統(tǒng)動(dòng)態(tài)特性影響分析

李　波,李郝林

(上海理工大學(xué) 機(jī)械工程學(xué)院,上海　200093)

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軸承預(yù)緊力對(duì)滾珠絲杠系統(tǒng)動(dòng)態(tài)特性影響分析

李波,李郝林

(上海理工大學(xué) 機(jī)械工程學(xué)院,上海200093)

摘要為了解軸承預(yù)緊力對(duì)滾珠絲杠系統(tǒng)動(dòng)態(tài)特性的影響,以某臥式磨床滾珠絲杠為研究對(duì)象,建立了絲杠的三維模型,并以彈性支承約束模擬角接觸球軸承對(duì)絲杠的支承。在此基礎(chǔ)上,利用ANSYS對(duì)磨床滾珠絲杠系統(tǒng)進(jìn)行模態(tài)分析。通過(guò)修改不同預(yù)緊力下軸承的支撐剛度,得到了在不同預(yù)緊力下的系統(tǒng)各階固有頻率。分析結(jié)果表明,在不同的軸承預(yù)緊力下,滾珠絲杠系統(tǒng)的結(jié)構(gòu)剛度會(huì)發(fā)生變化,使系統(tǒng)的固有頻率改變,且隨著預(yù)緊力增大而增大。磨削狀態(tài)穩(wěn)定時(shí),磨削預(yù)應(yīng)力對(duì)滾珠絲杠系統(tǒng)的影響較小。

關(guān)鍵詞滾珠絲杠;軸承;預(yù)緊力;模態(tài)分析

Modal Analysis of Ball Screw System of Grinder

LI Bo,LI Haolin

(School of Mechanical Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

AbstractA finite element model taking the ball screw of a horizontal hone as the research object is established to study the effect of bearing preload on the dynamic characteristic of ball screw system.Elastic constraint is used to simulate the supporting to ball screw exerted by bearings.A modal analysis based on the finite element method is accomplished.The natural frequency under different pretightening force is obtained by modifying the support stiffness on different bearing preload.The results show that the stiffness of a ball screw system changes under different bearing preload,and thus the natural frequency of the system increases with increasing preload.

Keywordsball screw;bearing;preload;modal analysis

滾珠絲杠是工具機(jī)械和精密機(jī)械上常用的傳動(dòng)元件,其主要功能是將旋轉(zhuǎn)運(yùn)動(dòng)轉(zhuǎn)換成線性運(yùn)動(dòng),或?qū)⑴ぞ剞D(zhuǎn)換成軸向反復(fù)作用力,同時(shí)兼具高精度、可逆性和高效率的特點(diǎn)。滾珠絲杠對(duì)進(jìn)給系統(tǒng)的工作能力及機(jī)床的可靠性產(chǎn)生重要影響[1]。在大型數(shù)控機(jī)床中,絲杠行程較長(zhǎng),進(jìn)給系統(tǒng)的剛度和抗振性會(huì)相應(yīng)地下降,尤其在切削力比較大時(shí)振動(dòng)比較嚴(yán)重,不但容易造成刀具的快速磨損,且會(huì)影響加工精度和加工表面質(zhì)量[2]。因此,仔細(xì)研究滾珠絲杠的動(dòng)態(tài)性能對(duì)于改善數(shù)控機(jī)床進(jìn)給系統(tǒng)的工作能力具有重要意義。然而,完整的滾珠絲杠副模型較為復(fù)雜,這會(huì)加大分析完整的滾珠絲杠副的的難度。……