One, the development of main shaft servo as numerical control technology, machine tool of contemporary numerical control is right advocate transmission raised taller and taller requirement. If ask the rotate speed inside very wide range is successive and adjustable, the limits of constant power wants wide, want to have the drive capacity of 4 quadrant. Change the need of knife and certain treatment craft automatically to satisfy machining center, those who ask main shaft has high accuracy is accurate stop control to wait. Gearshift of main shaft drive basically uses two kinds of forms at present is main shaft electromotor takes gear section infinitely variable speeds; 2 it is main shaft electromotor pass main shaft of belt of synchronous tooth form or leather belt drive, electromotor of this kinds of main shaft calls wide region electromotor or strong cutting electromotor again, have the characteristic with constant broad power. Of main shaft stop control to divide machinery to stop definitely definitely with electric stop definitely, at present domestic and international in system of high-grade numerical control all is used electric stop control definitely. Drive of main shaft of dc of system of drive of ⑴ dc main shaft uses brilliant brake to provide timing way more, dc feed servo is the armature voltage that the double-loop control system that makes by speed annulus and voltaic annulus will come to control electromotor of dc main shaft, main shaft electromotor uses motor of his encourage type, excitation winding and armature winding become independent each other. Electromotor rotate speed arrives from the least value rating, carry excitation electricity changeless, implementation is pressure regulating timing, belong to constant torsion control; Arrive from rating maximum, excitation electric current is reduced, implementation moves magnetism timing, belong to constant power control. System of drive of ⑵ communication main shaft develops as what exchange timing technology, at present the main shaft drive of numerical control machine tool uses main shaft electromotor to match the control pattern of transducer more. The circuit of commutate of three-phase bridge-type fully control that electrified wire netting carries inverter to be in charge of composition by 6 brilliant brake is comprised, this circuit can work in rectification condition, to intermediate circuit direct power supply, also can work in inversion condition, the task load of electrified wire netting of feedback of the energy that finish carries inverter by take the 6 power transistor that turns over diode of shunt-wound follow on current to comprise. Pass the control of magnetic field computer, load carries inverter to output wide modulation of three-phase sine arteries and veins (PWM) voltage, make electromotor obtains needs torsion electricity and excitation electric current. The limits of amplitude of three-phase PwM voltage of output is. 0 ～ 430v, frequency adjusting range. 0 ～ 300Hz. When feedback apply the brake, electromotor energy charges to capacitor through the diode of 6 follow on current of converter, when the voltage on capacitor exceeds 600V, the energy that gets on capacitor through controlling adjuster and electrified wire netting to carry inverter returns electrified wire netting. 2, means of wide modulation of arteries and veins of servo of feed of means of wide modulation of arteries and veins of feed servo ⑴ (PWM) timing is to use wide modulator of arteries and veins to undertake controlling to the switch time of high-power transistor. rate control signal is changed into the square wave voltage of certain frequency, the armature that adds dc servo electromotor two end, pass the control of square wave width, change armature the average voltage of two end, achieve the goal that controls servo electromotor rotate speed. The CPU of numerical control system gives out signal classics interpolation implement output a series of pulse signal, after these pulse pass instruction multiplicator CMR, with the position feedback pulse photograph compares the poor cost of earning, send an error register, compensate operation evacuation PWM to undertake wide modulation of arteries and veins with positional gain and deflection quantity next, subsequently classics D/A is changed or imitate voltage, as speed control signal VCMD sends speed to control unit. The pulse menopause line that pulse coder utters is checked implement affirm after breaking a string without signal, send phase discriminator, have look of ancient bronze mirror to PA of two groups of pulse, PB, decide the direction of rotation of electromotor. Come out from phase discriminator all the way commutation of signal classics F/V, regard speed as feedback signal TSA; Another output classics detects frequency multiplier DMR, regard the position as feedback signal. Reference point tally and turn signal PC is operated with what wind reference point at bar case law. Although servo of feed of dc of servo of drive of ⑵ communication feed has good timing function, but because what use electromotor to have brush and commutator, easy wear away, and the meeting when commutator inverting produces scintilla, make the top rotate speed of electromotor is restricted thereby. Additional, dc motive structure is complex, production difficulty, place is used up with cupreous iron material big, production cost is high, and AC motor does not have these defect however. Come nearly 20 years, as the occurrence of parts of an apparatus of new-style high-power electric power, the headway that the breakthrough gets the better of was gained theory of technology of new-style frequency conversion, contemporary control and technology of microcomputer number control in applying actually, promoted the flying development that exchanges feed servo technology, communication feed servo already replaced dc feed servo in the round. Because communicate servo electromotor to use motor of communication magneto synchronism, accordingly, communication feed actuating device from the dc motive actuating device that saying substantially is an electron inverting. CNC MillingCNC Machining