Brief introduction of main shaft coder

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One, the task introduces the working principle that narrates main shaft coder and its application. 2, coder of task analysis main shaft applies at be when whorl of car of numerical control lathe, it is the control signal that uses its to synchronous pulse is nodded as lathe tool feed and retreat a knife to nod, make sure turning whorl won't be buckled in disorder thereby. How is whorl machined? Should dot of lathe tool feed lie with the dot that retreat a knife what position? What effect does main shaft coder have? 3, relevant knowledge 1. Whorl whorl is what to form along corkscrewed yarn place is in on columnar face or taper seat, those who have figure of same section plane is successive and raised with groove. In cylinder apparently formation whorl weighs columnar whorl, in conic apparently formation whorl weighs conic whorl. In the whorl that swing tower forms on outside face the whorl outside saying, inside swing tower apparently formation whorl says inside whorl. The method that machines whorl is very much, when whorl is added on lathe, lathe passes 3 claw chuck clamp is cylindrical workpiece, drive it to make etc fast whirligig, lathe feed orgnaization drives lathe tool (standard whorl lathe tool) make along columnar axes direction etc fast sharp movement, lathe tool point of a knife gives triangular groove to form triangular whorl thereby in workpiece surface cutting. If pursue,1 is shown. Graph 1 if the graph is shown 2 times,whorl is machined on lathe, thread machining from time to tome orbit only then dot (A dot, namely feed is nodded) with orbit terminus (B dot, retreat a knife to nod) namely. There is litre of enough fast feed to make sure the treatment of whorl is installed in thread machining contrail paragraph δ and fall fast retreat a knife paragraph δ ˊ , in order to eliminate the pitch error that servo lag causes. Graph 2 thread machining 2. The coder of action main shaft of main shaft coder uses as synchronous as main shaft photoelectricity pulse generator, pass the gear 1:1 on intermediate axisGround synchronism drive. Between the roll of main shaft of numerical control lathe and feed motion, without the direct connection of mechanical respect, to machine whorl, the rotate speed of the pulse number that gives feed servo electromotor with respect to the requirement and main shaft is due and relative answering relation, main shaft reached the connection action that moves to main shaft roll and feed since pulse generator. 4, the principle of generator of pulse of task executive photoelectricity is shown 3 times like the graph. On leakage CD, the edge is circumferential quarter have streak two rounds, outer lane is line of circumferential divide into equal parts, for example: 1024, as send pulse to use, inner ring only 1. On smooth column, quarter have pervious to light stripe A, B, C, the distance between A and B should assure to become when coincide of stripe of the either on stripe A and leakage CD, stripe B should go up with leakage CD the registration amlposition 1/4 of another stripe is periodic. All find a place for at the back of of the each stripe of smooth column photosensitive dynatron, form an output channel. Graph the scattering light that the principle graph bulb of generator of 3 photoelectricity pulse gives out gets together through condenser smooth epigenesis is parallel light, when leakage CD and main shaft synchronism rotate, because leak,occurrence coincide mixes the stripe on the stripe on CD and smooth column amlposition, make photosensitive canal gets the change with bright, dark light, cause size of the electric current inside photosensitive canal to produce change, commutate of classics of signal electric current magnifies circuit outputs rectangular pulse. As a result of stripe A and coincide of grain of light leak wire rod when, stripe B and 1/4 of another stripe amlposition are periodic, the weaveform that because of this A, B two passageways output is phasic also differ 1/4 is periodic. A reticle of inner ring of CD of the leakage in pulse generator and the pulse that output when coincide of C of the stripe on column solely are synchronism (start, weigh null again) pulse. Use synchronous pulse, numerical control lathe can realize treatment control, what also can regard main shaft as positioning device is accurate stop signal. When whorl of car of numerical control lathe, use synchronous pulse to regard the control that lathe tool feed is nodded and declines knife point as signal, in order to make sure turning whorl won't be buckled in disorder. 5, intellectual link 1. Numerical control machine tool detects to detecting element and position the requirement of device (machine tool of 1) numerical control is to detect to detecting element of detecting element requirement the important part of device, its main effect is to detect displacement and speed, send feedback signal. The volume of the smallest displacement that displacement testing system can measure calls resolution. Resolution depends on not only detecting element itself, also depend on measure circuit. Numerical control machine tool is to the main demand of detecting element: ① life is long, reliability is high, interference rejection capability is strong; ② satisfies precision and speed requirement; ③ is used safeguard convenient, suit a machine tool to run an environment; ④ cost is low; ⑤ facilitates with computer connection. The numerical control machine tool of different type is different to the requirement of the precision of testing system and speed. Normally machine tool of large numerical control asks to give priority to with satisfying speed, and medium, small-sized ask in order to satisfy precision to give priority to with machine tool of high accuracy numerical control. When the choice measures systematic resolution and pulse equivalent, general demand is higher than machining precision quantitative class. (Machine tool of 2) numerical control detects to the position the requirement position of device detects the main component that device is servo of numerical control machine tool. Its action is to detect displacement and speed, send feedback signal, make closed circuit or half closed-loop control. The treatment precision of numerical control machine tool basically is decided by the precision of testing system. The numerical control machine tool of different type, to positional detecting element, the precision requirement of testing system and the highest and floating rate of the component that be measured each are not identical. Now the top level of detecting element and system is: The highest and floating rate of the component that be measured comes high when 240m/min, its detect the resolution of displacement (the smallest displacement that can detect is measured) can amount to 1 μ M, when be like 24m/min, can amount to 0.

1 μ M. Highest resolution can be achieved 0.

01 μ M. Numerical control machine tool detects to the position device is like next requirements: The effect that ① suffers temperature, humidity is little, the job is reliable, can maintain precision for a long time, interference rejection capability is strong. ② is inside limits of shift of machine tool executive component, can satisfy the requirement of precision and speed. ③ is used safeguard convenient, get used to environment of machine tool work. ④ cost is low. 2. The position detects the classification of device the numerical control machine tool to different type, because working requirement is mixed,detect the demand is diverse, can use what differ below to detect means. (1) increment type and very form measure increment type to detect means measures displacement increment only, represent unit displacement with a number of digital pulse (namely unit of the smallest set) amount, every shift measures an unit to give out to measure signal. Its advantage is to detect device is simpler, any can serve as to midpoint measure start. But the system is here medium, move after relying on to be accumulated to measuring signal, be apart from numerate, once accumulative total has by accident, the measurement of after this the result will be completely bad. Be in additionally when malfunctioning (if cut off the power) the proper place that cannot find preaccident again, after the accident eliminates, must move workbench the proper place that to start new count ability finds preaccident. Pulse coder, rotate transformer, inductive synchronized, grating, magnetism bar, laser interferometer is increment detects device. Very form measures means to measure those who go out is the absolutely coordinate position in some world coordinate system is worth the component that be measured, and express with binary system or signal of decimal numeral code come out, after wanting to become pulse number signal through changeover commonly, ability sends undertake compare and indication. Use this means, resolution asks to heal tall, the structure also heals complex. Such measurement unit has very form pulse to code dish, 3 fast type code absolutely dish (or call type many rounds absolutely encode dish) etc. (2) number type and imitate type measure digital type to detect is after quantifying unit be metricaled, express with digital form. Measure signal to be electric pulse commonly, can send numerical control system to undertake comparative it directly, processing. Such detecting device has pulse coder, grating. Digital type detects have the following 3 characteristics. ① is measured to be changed into pulse several, facilitate show and handle; ② measures precision to depend on measure an unit, have nothing to do basically with span; But existence accumulative total piles up difference by accident; ③ detects device is simpler, capability of pulse signal interference rejection is strong. Imitate type detects is will be measured to use successive variable to express, if the amplitude of voltage changes, phasic change. When mathematical imitate formula is done to detect inside a large number of Cheng, have higher demand to the technology, type of the imitate in numerical control machine tool detects basically use at grain Cheng to measure. Imitate type detects device has measure fast dynamo, rotate synchronized of transformer, induction and magnetism feet. The main characteristic that imitate type detects has the following. ① detects to be being measured to undertake directly, need not quantify. ② can realize high accuracy to measure inside grain Cheng. ③ can undertake detect directly and detecting secondhand. The position detects device installation is implementing a part (namely extreme) go up to measure executive component extreme directly linear displacement or angular displacement, can call measure directly, can form servo of closed circuit feed, measure means to interferometer of bar of synchronized of linear grating, sharp reaction, magnetism, laser waits for the linear displacement that measures executive part; Because this kind detects,means is to use linear model detect device is measured to what the linear displacement of the machine tool undertakes. Its advantage is the linear displacement volume that reflects workbench directly. Defect is to ask to detect device and journey long, to large machine tool, this is a very big limitation. The position detects on the transmission component that device installation is before executive component or axis of drive electric machinery, measure its angular displacement, the linear displacement that after comparing commutation through transmission, ability gets executive a part is measured, such calling indirect measurement, can make system of feed of servo of half closed circuit. If install pulse coder,go up in electric machinery axis. Indirect measurement is used go to the lavatory reliably, without length limitation; Its defect is to detecting the transmission catenary error that sharp change joined to be whirligig in signal, affect thereby measure precision. Need to undertake compensating to the transmission error of the machine tool commonly, ability raises fixed position precision. Detect besides above position device, include to detect toward contact in servo the component of speed, in order to detects and adjust the rotate speed of engine. Commonly used detecting element is to measure fast engine. The position with numerical control common machine tool detects device sees next tables. The position with common watch detects coder of very form circumgyrate pulse, change coming back presses type of device type increment implement, bar of round induction synchronized, round grating, round magnetism is much fast rotate coder of transformer, absolutely pulse, 3 fast circles CNC Milling CNC Machining