【摘要】：超精密機(jī)床垂直軸可以拓展機(jī)床的加工方式,提升機(jī)床的加工能力,是超精密多軸聯(lián)動(dòng)機(jī)床的重要組成部件。而現(xiàn)有超精密機(jī)床垂直軸的卸荷系統(tǒng)存在摩擦系數(shù)大的缺點(diǎn),嚴(yán)重影響到超精密機(jī)床垂直軸的定位精度和加工穩(wěn)定性。為解決上述問題,本文為現(xiàn)有超精密機(jī)床垂直軸設(shè)計(jì)了以氣體潤滑低摩擦氣缸為核心部件的卸荷系統(tǒng),并對其氣體靜壓徑向軸承的靜態(tài)性能,以及卸荷系統(tǒng)的靜動(dòng)態(tài)特性進(jìn)行了研究與分析。本文具體的研究內(nèi)容有:基于低摩擦的設(shè)計(jì)原則,以氣體靜壓潤滑為理論基礎(chǔ),并結(jié)合典型低摩擦氣缸的結(jié)構(gòu),設(shè)計(jì)了可以實(shí)現(xiàn)氣體潤滑環(huán)節(jié)與卸荷環(huán)節(jié)獨(dú)立供氣的全工況超精密機(jī)床垂直軸卸荷系統(tǒng)。通過推導(dǎo)Reynolds方程的一般表達(dá)式,建立了氣體靜壓徑向軸承靜態(tài)特性數(shù)學(xué)模型,并由此完成了對氣體靜壓軸承各尺寸參數(shù)的選取,計(jì)算了軸承承載力、靜剛度和耗氣量等靜態(tài)性能參數(shù)。完成了卸荷系統(tǒng)配套氣動(dòng)回路的設(shè)計(jì),使卸荷系統(tǒng)能夠在氣體潤滑的狀態(tài)下完成卸荷任務(wù)。在卸荷系統(tǒng)總體結(jié)構(gòu)設(shè)計(jì)的基礎(chǔ)上,通過仿真軟件Fluent對卸荷系統(tǒng)內(nèi)的氣體靜壓徑向軸承的靜態(tài)性能進(jìn)行了分析;研究了氣體靜壓徑向軸承上氣體壓強(qiáng)分布對軸承承載力和靜剛度等靜態(tài)性能的影響;研究了偏心率、軸承徑向間隙和供氣壓力等參數(shù)對軸承靜態(tài)性能的影響規(guī)律,并確定了各參數(shù)的最佳取值�；谛逗上到y(tǒng)的有限元模型,對活塞桿不同姿態(tài)下的卸荷系統(tǒng)進(jìn)行了結(jié)構(gòu)靜力學(xué)分析,并完成了卸荷系統(tǒng)的彎矩敏感性分析。對活塞桿不同位置下的卸荷系統(tǒng)進(jìn)行了模態(tài)特性分析,分析了活塞桿姿態(tài)變化對卸荷系統(tǒng)各階固有頻率與模態(tài)振型的影響。對卸荷系統(tǒng)的氣體潤滑低摩擦氣缸進(jìn)行了性能試驗(yàn),得到了其靜摩擦力隨供氣壓力與負(fù)載質(zhì)量變化的規(guī)律。
[Abstract]:The vertical axis of ultra-precision machine tool can expand the machining mode of machine tool and improve the machining ability of machine tool. It is an important component of ultra-precision multi-axis machine tool. However, the present unloading system of vertical axis of ultra-precision machine tool has the disadvantage of large friction coefficient, which seriously affects the positioning accuracy and machining stability of vertical axis of ultra-precision machine tool. In order to solve the above problems, a unloading system with gas lubricated low friction cylinder as the core component is designed for the vertical axis of the existing ultra-precision machine tool, and the static performance of the gas hydrostatic radial bearing is also studied. The static and dynamic characteristics of unloading system are studied and analyzed. The specific research contents of this paper are as follows: based on the design principle of low friction, based on the theory of gas hydrostatic lubrication, and combined with the structure of typical low friction cylinder, The vertical axis unloading system of ultra-precision machine tool under all working conditions is designed, which can realize the independent gas supply between gas lubrication and unloading. By deducing the general expression of Reynolds equation, the mathematical model of static characteristic of aerostatic radial bearing is established, and the parameters of each dimension of gas hydrostatic bearing are selected, and the bearing capacity is calculated. Static performance parameters such as static stiffness and air consumption. The design of the complete pneumatic loop of the unloading system is completed, which enables the unloading system to complete the unloading task under the condition of gas lubrication. Based on the overall structure design of the unloading system, the static performance of the aerostatic radial bearing in the unloading system is analyzed by the simulation software Fluent. The influence of gas pressure distribution on bearing capacity and static stiffness is studied, and the influence of eccentricity, radial clearance and air supply pressure on static performance of bearing is studied. The optimum value of each parameter is determined. Based on the finite element model of the unloading system, the structural statics analysis of the unloading system with different piston rod attitude is carried out, and the moment sensitivity analysis of the unloading system is completed. The modal characteristics of the unloading system with different piston rod positions are analyzed, and the influence of the piston rod attitude change on the natural frequencies and modal modes of the unloading system is analyzed. The static friction of the gas lubricated low friction cylinder of unloading system is tested, and the variation of static friction force with the air supply pressure and load mass is obtained.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG502.1
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本文編號(hào)：2238493