This paper deals with the investigation for slide unit's impact and motion stabil¬ity in modular machine tool fay means of the method of power bond graph and state space analysis. The dynamic mathematical model of self-adjusting back pressure speed control system used to drive slide unit is established. Main reasons and affect¬ing factors for slide unit impact and motion unstability are analysed through compu¬ter digital simulation, It is concluded from those that, if the structural dimensions of hydraulic cylinder and back pressure valve are designed rationally, the slide unit's dynamics will markedly be improved.
NOMENCLATURE
Sf flow source
Sei sliding friction force in slide unit
R equivalent viscous friction coefficient in slide unit
Ii mass of slide unit and cylinder
h mass of SABP valve spool
Ci,C2 hydraulic capacitances of rod chamber and non-rod chamber in cylinder re-
spec-tively
C3 spring compliance of SABP valve
R]rR2 hydraulic resistances of damping holes
R9 hydraulic resistance of orifice of SABP valve
Se2 presetting force of spring in SABP valve
I4J5 equivalent liquid inertia in pipe lines
C^Cg equivalent hydraulic capacitances in pipe lines
equivalent hydraulic resistances in pipe lines

V-j V^ oil-containing volumes in non-rod chamber and rod chamber respectively
P,r:, P-i oil pressures in non-rod chamber and rod chamber respectively
F load acted on slide unit
V slide unit velocity
* Department of Mechanical Engineering, Dalian Ur.iversity of Technology, Dalian. China.
【摘要】這一張紙?zhí)幚碚{(diào)查利用有束縛力的曲線圖和狀態(tài)空間分析法對(duì)組合機(jī)床滑臺(tái)的滑動(dòng)影響和運(yùn)動(dòng)平穩(wěn)性問題進(jìn)行分析與研究，從而建立了滑臺(tái)的液壓驅(qū)動(dòng)系統(tǒng)一自調(diào)背壓調(diào)速系統(tǒng)的動(dòng)態(tài)數(shù)學(xué)模型。通過計(jì)算機(jī)數(shù)字仿真系統(tǒng)，分析了滑臺(tái)產(chǎn)生滑動(dòng)影響和運(yùn)動(dòng)不平穩(wěn)的原因及主要影響因素。從那些中可以得出那樣的結(jié)論，如果能合理地設(shè)計(jì)液壓缸和自調(diào)背壓調(diào)壓閥的結(jié)構(gòu)尺寸.
本文中所使用的符號(hào)如下：
s1-流源，即調(diào)速閥出口流量；
Sel—滑臺(tái)滑動(dòng)摩擦力
R一滑臺(tái)等效粘性摩擦系數(shù)：
I1—滑臺(tái)與油缸的質(zhì)量
12—自調(diào)背壓閥閥心質(zhì)量
C1、c2—油缸無桿腔及有桿腔的液容；
C2—自調(diào)背壓閥彈簧柔度；
R1, R2自調(diào)背壓閥阻尼孔液阻，
R9—自調(diào)背壓閥閥口液阻
Se2—自調(diào)背壓閥彈簧的初始預(yù)緊力；
I4, I5—管路的等效液感
C5、C6—管路的等效液容：
R5, R7-管路的等效液阻；
V3, V4—油缸無桿腔及有桿腔內(nèi)容積；
P3, P4—油缸無桿腔及有桿腔的壓力
F—滑臺(tái)承受負(fù)載，
V—滑臺(tái)運(yùn)動(dòng)速度。本文采用功率鍵合圖和狀態(tài)空間分折法建立系統(tǒng)的運(yùn)動(dòng)數(shù)學(xué)模型，滑臺(tái)的動(dòng)態(tài)特性可以能得到顯著改善。