具特殊擠壓油膜軸承主軸系統之自由及強迫振動分析

The Analysis of Free and Forced Vibration of the Spindle System with a Special Squeeze Film Bearing

蘇柏丞(Po-Chen Su)

指導教授 ： 劉德騏 ； 蕭庭郎

國立中正大學/工學院/機械工程學系/碩士(2013年)

摘要

本文主要探討具特殊擠壓油膜軸承主軸系統自由及強迫振動分析，系統中心架構為車床主軸，搭配的特殊擠壓油膜軸承主要由滾珠軸承及籠型支撐座(Squirrel cage supported structure)所組成。首先，以雷諾方程式（Reynolds' equation）配合擠壓膜邊界推導出擠壓油膜壓力分佈，再沿軸承圓周積分得到擠壓油膜力，本文不考慮油膜徑向速度項次下，將油膜力線性化，進而得出具線性擠壓油膜力之系統運動方程式。
本文探討具特殊擠壓油膜軸承在不同油膜黏滯係數及油膜間隙下，與主軸同步運轉時之動態特性，數值結果顯示，籠型支撐座剛性逐漸增大時，前兩模態臨界轉速在較高籠型支撐座剛性下，出現臨界轉速轉向(Veering)現象。另外，高剛性籠型支撐座配合擠壓油膜軸承油膜阻尼，能明顯抑制不平衡力所激發出主軸系統第一自然頻率下之不平衡響應。

關鍵字

轉子軸承系統 ； 不平衡響應 ； 特殊擠壓油膜軸承 ； 雷諾方程式

並列摘要

This study focus on the analysis of the free and forced responses of the lathe spindle system with special squeeze film bearing. The special squeeze film bearing is composed of a ball bearing and a squirrel cage supported structure. At first the Reynolds' Equation is used to derive the pressure distribution of a squeeze film bearing with the boundary condition of a squeeze film. Then the force of the squeeze film can be obtained by integrating with the pressure distribution along the squeeze film. The radial velocity of oil-film is ignored during the linearization of the oil force. Finally, the system equation of motion for the spindle system can be derived.
This study discuss the dynamic behavior of the spindle system with the special squeeze film bearing under the effects of parameters including the oil viscosity coefficient and oil clearance. The results show that veering phenomenon of critical speed occurs obviously at the first two natural frequency at high stiffness of squirrel cage supported structure. Besides, the high stiffness of the special squeeze film bearing and squeeze film damping can suppress the unbalance response at first natural frequency which excited by unbalance force.

並列關鍵字

Unbalance Response ； Rotor-bearing system ； Reynolds' Equation ； Special squeeze film bearing

參考文獻

(1) Ruhl, R.L. and Booker, J.F., 1972, "A Finite Element Model for Distributed Parameter Turborotor Systems", ASME journal of Engineering for

(2) Nelson, H.D. and McVaugh, J.M., 1976, "The Dynamics of Rotor-Bearing Systems Using Finite Element", ASME journal of Engineering for

(3) Nelson, H.D., 1980, "A Finite Rotating Shaft Element Using Timoshenko Beam Theory", ASME journal of Mechanical Design, Vol.102, pp.793-803.

(4) Lund, J.W., 1979, "Sensitivity of the Critical Speed of a Rotor to Change in the Design", ASME journal of Mechanical Design, Vol.102, pp.115-121.

(5) Rajan, M., Nelson, H.D., and Chen, W.J., 1986, "Parameter Sensitivity in the Dynamics of Rotor-Bearing System", Transaction of the ASME journal of