Gearshift is not research of technology of round turning key

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Summary: Be not round turning stability to rise, speed change treatment introduces the turning that be not a circle to form gearshift to be not round turning. This article compose built gearshift to be not round turning construction of system, established the mathematical model that ration of main shaft gearshift depicts and diagnostic parameter, designed comfortable the linear servo that is not round turning at gearshift is unit, studied gearshift treatment raises the mechanism that machines stability. The result makes clear: In drive of appropriate main shaft drive function and gearshift parameter condition fall, linear servo unit can dog well the target cost that cutting tool moves, raise turning stability and treatment precision effectively thereby. 1 foreword is not round CNC Turning is implementation blame the effective method that efficient, Gao Rou sex, high accuracy machines round sectional spare parts. The core of the CNC Turning that be not a circle is drive cutting tool the high frequency noisy high accuracy that does radial reciprocate is linear servo is unit, the position that it is a kind of model is followed use a system. Because linear servo is unit medium actuator always has certain response speed, accordingly, cutting tool arises inevitably relative to the deflection at target position, namely: Expression of virtual campaign contrail is cutting tool vibration of low frequency ideal and the overlay with high frequency oscillatory noise. Vibration of high frequency noise reflected the stability of process of the turning that be not a circle, its extent affected the part that be not a circle directly the dimension precision of sectional outline. Raise the treatment precision that is not round sectional spare parts, want to increase stability of the turning that be not a circle namely, reduce scope of vibration of high frequency noise. Gearshift is machined (Variable Spindle Speed Machining, VSM) concept is German Stoferle, t.

The professor improves the stability that turning machines at put forward the earliest 1972 and be being used. When gearshift is machined, main shaft rotate speed makes successive periodic change with certain frequency and extent on a basic rotate speed. Gearshift treatment research is main from mechanism and application two respects undertake. The field researchs in application, speed change treatment applies in turning, grinding and milling respectively, be chosen through what experimental method discusses gearshift cutting parameter and optimize. The field researchs in mechanism, emphasize from theory treatment of angle discussion gearshift checks the oscillatory, reason that increases treatment stability and qualification. Build a model through building the maths that machines a process, with emulate, the method such as the experiment comes test and verify its academic validity. speed change treatment introduces the turning that be not a circle to form gearshift to be not round turning, its purpose should offer a kind of new raising to be not the way of round turning stability namely, with satisfying the part is not a circle that raises ceaselessly sectional outline precision asks. The construction of system that the article emphasizes round to gearshift blame turning, . The crucial technology such as the mechanism that unit of description of character of main shaft gearshift and implementation, linear servo is designed and gearshift treatment increases stability undertook study. Construction of system of round turning of 2 gearshift blame pursues 1 gearshift is not gearshift of round turning construction of system to be not round turning is to be on the foundation of system of the CNC Turning that be not a circle, the function of successive gearshift drive that increases main shaft and those who form. Its construction of system is shown 1 times like the graph. Gearshift is not round turning system to be mixed by driving unit of unit of unit of servo of machine tool noumenon, general numerical control, linear servo, main shaft 5 parts comprise control computer. The machine tool uses structure of general center lathe, but undertook be designinged technically to lathe bed and main shaft structure, in order to make sure the machine tool has very good structure stiffness and precision of main shaft circumgyrate. Unit of servo of general numerical control introduces drive of communication servo electric machinery, the control plate of much axis motion that deserves to be based on DSP, x of edge of lathe of the implementation below the control in numerical control software to with Z to numerical control moves. Linear servo unit uses high frequency noisy linear electric machinery to be drive component, installation of linear electric machinery procrastinates in the horizontal stroke of lathe board on, cutting tool installation is on the take-off of electric machinery. X of edge of cutting tool of implementation of cutting tool of drive of linear servo unit to accurate reciprocate, the blame circle that gives a part in order to machine is sectional outline. Glazed bar sensor stays to feedback in real time in the other one aspect of the matter of take-off of linear electric machinery the athletic position of linear electric machinery, the closed circuit follow-up control of linear servo unit comes true below the support of special controller. Main shaft driving unit machines the gearshift frequency of the main shaft of the requirement and extent according to gearshift, through controlling software and driver of main shaft gearshift to come electric machinery of drive main shaft makes it is pressed book requirement roll. The main shaft coder of back end of main shaft electric machinery offers main shaft to turn signal gives linear electric machinery special controller and controller of much axis motion in real time, in order to coordinate a system the movement between each part. Between cutting tool of the implementation below the control of system of gearshift blame round turning in the computer and workpiece accurate, harmonious motion, the spare parts is not a circle that machines a different and sectional appearance and different precision requirement. Graph the mathematical model that description of character of gearshift of 3 main shaft and ration of gearshift of implementation main shaft depict curve of gearshift of 2 main shaft and diagnostic parameter are not round turning process in gearshift in, main shaft rotate speed is periodic on a basic rotate speed fluctuant, if pursue,2 are shown. The type of character of main shaft gearshift and periodic fluctuant function and diagnostic parameter are concerned. The angular velocity of periodic change can use main shaft next type represent: W(t)=w0+Afunction(2pft) , (In 1) type, w0 gives priority to basic angular velocity of the axis, a gives priority to the extent that axial angular velocity changes, f is the frequency that angular velocity changes, function is random a periodic function, for example: Sine wave function, trigonometry wave function, square wave function. Expression is the boundless key link that this speed changes: W(t)=w0(1+RVAfunction(RVFw0t) , (In 2) type, RVA=A/w0 shows the opposite extent that speed changes, RVF=2pf/w0 expresses the opposite frequency that speed changes. By go up type is knowable, RVA and RVF ration described the extent that main shaft speed changes at basic rotate speed relatively and frequency, it is the diagnostic parameter of main shaft gearshift. The implementation of main shaft gearshift by before narrate knowable, the incentive function of main shaft drive is a periodic function, will change main shaft rate with this. But can control function of gearshift of main shaft electric machinery to get, analyse of part of one's job decides the type of incentive function and diagnostic parameter. The function of speed contrail drive that has simple outline normally has sine wave, trigonometry wave and square wave 3 kinds. If function of drive of electric machinery drive uses sine wave, so the angular acceleration with rotational electric machinery and horny thrust change are sine or cosine function, be successive change: And when incentive function uses trigonometry wave, the angular acceleration with rotational electric machinery is square wave change, but is horny thrust change infinity: ? Plum of take along sth to sb of  of  of Shou だ  tells ǎ  to knock uranous Yu of Qiang of admire of  of  of the  that blow black group? of toad of the She nationality of spruce big-eared of border of  of Xi of Tu Qiaobing Ρ is mixed from the drive of electric machinery answer look, if systematic angular acceleration is big, so the power of the electric machinery of drive main shaft and electric current are big: If change of systematic horn thrust is big, so the sudden change of electric machinery electric current is big. Accordingly, from obtain the function of gearshift of main shaft electric machinery that can control to look, sine wave is had than other wave better dog function, more comfortable at regarding the electric machinery drive when main shaft gearshift as incentive function. On the other hand, servo of load of inertia of unit of motion of the RVF that system of main shaft gearshift allows and RYA parameter span and power of main shaft electric machinery, main shaft, cutting, main shaft dogs the element such as function is concerned. Actual RVA and RVF can change inside permission parameter range only. Unit of 4 linear servo designs gearshift to be not the linear servo unit in round turning system is system of follow-up control of a closed circuit, it according to the program given cutting tool of athletic contrail drive does nicety of radial move back and forth to dog motion, thereby the sectional outline appearance that fast, neatly treatment gives the different part that be not a circle, satisfy its precision requirement. Graph unit of 3 linear servo is nonlinear dog design of controller construction controller is had to make linear servo unit very tall dog precision, can resist the outside disturbs the effect that causes with in-house parameter change, article application is nonlinear control designed linear of Central Africa of unit of a linear servo to dog theoretically controller door, say to fight faze controller oneself again, its structure is shown 3 times like the graph. Nonlinear dog controller is to transforming the development on the foundation of traditional PID to rise. After inputting signal dog differential implement be nonlinear dynamic link, it is reasonable collect differential signal, those who because input signal,avoid cannot small of the differential signal that cause lack fidelity. The instead of the sue for peace that increase advantageous position of will original PID is nonlinear set sum. Design a nonlinear outspread condition observation implement, hand-in-hand travel compensates all sorts of condition variable that estimate control process in real time, in order to raise rash club sex of the system. Controller algorithm is accused the object is linear electric machinery, course identifying can be approximately 2 rank system, model of its condition space is: (In 3) type, set input signal to be V, output signal is Y, control quantity is U, pursue 3 specific algorithm that show controller are as follows: Arrangement transfers process, extraction differential signal is dogging differential implement in, should input V of a signal, it outputs generation 2 times signal V1 and V2, among them V1 dogs input signal V, v2 is the differential of V1. Dog differential implement disperse equation is: {v1(k+1)=v1(k)+hv2(k) , v2(k+1)=v2(k)+hfst(v1(k)-v(k) , v2(k) , r, in H)(4) type, h grows for the pace, it has filter wave effect to noise, decide according to sampling time: : For rate factor, the decision dogs speed. Function. The expression of Fst is: (5) estimation condition and because be accused to be opposite,always disturb seem 2 rank system, because of this outspread condition observation implement will produce Z1 of 3 condition signal, Z2, Z3, its disperse equation is: (The B01 in 6) type, B02, B03, A1, A2 is adjust parameter, nonlinear function Fal takes for: (The formation that 7) control measures controls a quantity to use calculation leaving type: (This ideal data-in V(t) that the algorithm of controller requires linear electric machinery only mixes 8) to output data Y(t) actually. Graph unit of 4 linear servo dogs function test result emulates an experiment according to afore-mentioned algorithm, to be being accused the object undertook dogging experiment, if pursue,4 are shown. Graph 4 in the target cost that linear servo unit moves is type (the disperse of 2) is numeric, each parameter takes a value to be as follows: W0=251(rad/s) of basic angular velocity, RVA=0.

2, RVF=0.

1, (A-b)/2=100(µm) . Right now the basic rotate speed of the main shaft of corresponding piston CNC Turning is ± of change of 1200r/min, rate 240r/min, ovality 0.

The gearshift of 4mm is not round turning. By the graph 4 can see, when gearshift is not round turning, be based on nonlinear pilot is linear servo unit can dog well input signal, the biggest tracking error is ± 4µm. The linear electric machinery that 5 gearshift treatment improves mechanism of stability of the turning that be not a circle to be not cutting tool of the drive in round turning system is system of damp of a bedspring. In turning process, the electric magnetism that linear electric machinery outputs overcomes Xiang Zhen of X of edge of cutting tool of bedspring force, damp force and cutting force drive to move. The virtual campaign contrail of cutting tool can consider as low frequency ideal vibration and the overlay with high frequency oscillatory noise. Vibration of low frequency ideal is one kind when cause by electromagnetism force forces vibration, its motion contrail decides by the appearance of academic and sectional outline of the spare parts that be not a circle: And a kind of self excited vibration that vibration of high frequency noise is the generation in machining a process, its extent expressed the precision of sectional outline dimension of this spare parts. The stability that increases the turning that be not a circle should reduce vibration of high frequency noise namely. The dynamic change of the electric magnetism that the cutting tool in process of the turning that be not a circle produces by linear electric machinery relative to the self excited vibration at workpiece and cutting force is caused, it is the result of the linear servo unit of drive cutting tool and cutting process interaction. As a result of self excited vibration maintain rely on oscillatory system itself, because this is inside every oscillatory cycle, the system draws energy not only and disappear energy consumption. Compare the situation that energy of the system in oscillatory process is absorbed and uses up, can judging vibration is strengthening still is attenuation. Force of the cutting in energy method is being used to analyse process of the turning that be not a circle below and electric magnetism are oscillatory to cutting tool the circumstance that the system does work, the energy that fixes a system thereby changes. The application with blame round the at present widest turning is the treatment of elliptical and sectional piston. Because piston accident axle shaft is poor the value is relative at axle shaft diameter very small, if set cutting tool,the displacement that is in in long axis is 0, criterion R(t) of vibration of cutting tool ideal can express to be: R(t)=a-b(1-cos(2wmt))2(9) sets vibration of cutting tool noise to be: X(r)=Xcos(wt+Ø) , so cutting force F(t) and electromagnetism force FE(t) are in N the result W that makes in oscillatory cycle is: (In 10) type: F(T)=Kcb(x(t)-X(t-t)+h0) , kc is coefficient of static cutting force, b is cutting width, the noise that X(t) and X(tt) are around two rounds respectively is oscillatory. FE(t)=2Kx(t)+F(t)+MR(t) . .


Second birth force and electric magnetism are inside every oscillatory cycle makes work is: (The current weaveform of vibration of noise of 11) cutting tool and undee last week differ protect can express to be: Ø=2pMm+em, the Mm= 0 in type, 1, 2L, 2p of ≤ of 0 ≤ Em. Course derivation can get: (12) by type (12) is knowable, when constant speed is not round turning, when Em=0 and Em=p, the system is in; of critical steady state to be stabilized when the system when 0<em<p, when Em=p/2, w is the smallest, best; becomes systematic stability the system when P<em<2p> is not stable, when Em=3p/2, w is achieved maximum, systematic stability is the poorest. This shows the turning that be not a circle and common circle turning have character of identical second birth vibration: Cutting tool noise is oscillatory increase and increase what Zhen Pin rate follows workpiece rotate speed ceaselessly quite namely, but show section zigzag change; On stability graph, each Mm value has correspondence curve of a lop-eared shape. When rotate speed of the main shaft in be not round turning process when gearshift produces change, cutting process stabilizes an area to undertake alternately in stable area and blame, state of this kind of cutting disturbed the abidance of second birth flutter undertakes. On the other hand, in blame stability area, vibration of cutting tool noise is drive of a kind of frequency conversion is answered, the response below frequency drive is secured when its amplitude should be less than constant speed turning, this makes the cutting tool noise when gearshift treatment reduces the turning that be not a circle effectively oscillatory, increase stability of the turning that be not a circle thereby. 6 conclusion are not turning of round numerical control is the effective method that treatment is not round sectional spare parts.

Be not round turning stability to rise, this paper introduces gearshift treatment the turning that be not a circle, the crucial technology that is not round turning to gearshift undertook study, reach through research the following conclusion: The extent of gearshift of main shaft of can mensurable description mixes RVA and RVF parameter frequency, function of sine body cycle is drive of a kind of drive of main shaft gearshift that comes true easily function. Be based on nonlinear dog linear servo unit has pilot to dog very well gender and rash club sex, the precision of the can contented turning that be not a circle asks. The noise vibration when gearshift is not round turning is a kind of self excited vibration, it has second birth quite brace up characteristic. The main shaft speed that gearshift machines the mechanism that increases stability of the turning that be not a circle to be based on gearshift disturbs and reduced original persistent second birth flutter. CNC Milling