The crucial technology of unit of feed of linear electromotor high speed

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Summary: To satisfy the requirement that exceeds high speed treatment, appeared in recent years means of a kind of new-style feed of drive of linear electromotor servo. The GD-3 that the article combines my school proper motion to develop high speed is linear electromotor feed is unit, introduced the option of the computation of linear electromotor parameter when designing unit of feed of linear electromotor high speed and composition of feed unit structure, the antimagnetic that studied linear electromotor and medicinal powder the concerned problem such as the design of the component such as hot issue, workbench and slideway and system of linear electromotor control. Consider to make clear, linear electromotor has good applied prospect on machine tool of high speed numerical control. High speed treatment is a burgeoning advanced production technology. To realize high speed treatment, besides should have high speed main shaft, return the rate that must raise feed system greatly at the same time and acceleration, ability makes machine be able to on the rails. What system of feed of conventional numerical control uses is " rotate servo electromotor + ball guide screw " transmission way. At present the speed of the biggest feed of common guide screw is 40m/min, the biggest linear acceleration is 0.

5g. And the oldest rate of guide screw of a few fast accurate ball already amounted to 60m/min, the biggest acceleration is amounted to 1.

0g. But transmission error of existence of way of this kind of transmission, attrition wears away, inertia is big, stretch be out of shape pose the problem such as creeping, retrorse dead band, ask in athletic speed taller circumstance, it is very difficult already to should achieve higher performance. In recent years, rise as what machine efficiency and quality requirement and the progress of linear electromotor technology, appeared means of a kind of new-style feed of drive of linear electromotor servo. It cancelled to arrive from electromotor among everything between workbench transmission link, be called to be " 0 drive " . Compare with photograph of way of transmission of ball guide screw, means of linear electromotor drive has feed rate tall, acceleration the big, thrust that start big, stiffness and fixed position precision length of tall, journey is unlimited wait for an advantage. Since first time of German Ex-Cell-O company used linear motor at machining center 1993, unit of this kind of new-style high speed feed already caused the widespread attention of world each country. Beautiful, heart, day, flower the research that waited for industrial developed country to have development to linear electromotor product and development, the high speed machining center that uses linear electromotor drive already made one of development way of 21 centuries machine tool. Our country has started to the research of linear electromotor, but the difference that is the same as abroad is very big still. The article joins unit of feed of high speed of the GD-3 that my school proper motion develops linear electromotor, introduced how to decide the design parameter of unit of feed of linear electromotor high speed, configuration, discussed to affect a few crucial questions of performance of system of feed of linear electromotor high speed mainly. The design of unit of feed of high speed of 1 linear electromotor is linear unit of feed of electromotor high speed is main survey a system by slideway of linear electromotor, workbench, scroll, feedback, defend the 5 parts such as the system are comprised. Graph the cross section graph of the unit of feed of high speed numerical control that type of the GD-3 that 1 exceed high speed treatment and development of machine tool laboratory for my school induction exchanges linear electromotor drive. The rated feed speed that feed unit should press a demand, rated thrust and acceleration will design or choose linear electromotor, apply a circumstance to decide the configuration of feed unit according to its, in designing a process, the antimagnetic that considers linear motor even, come loose to heat up and defend wait for a problem. 1.

Workbench 2.

Shield 3, 12.

Slideway 4.

Lathe bed 5, 8.

Auxiliary slideway 6, 14.

Dead plate 7.

Sub 9.

Survey a system 10.

Grating feet 11.

Towline 13.

Unit of feed of high speed of primary plan 1 GD-3 linear electromotor is linear the characteristic curve of the affirmatory and linear electromotor of basic parameter is like electromotor the graph is shown 2 times, below full enough 3 requirements answer when designing or choosing linear electromotor: Graph the characteristic curve of 2 linear electromotor 1.

Workpiece 2.

Work station 3.

Slideway 4.

Lathe bed 5.

Slide block pursues unit of feed of 3 linear electromotor suffers in type of Feff of ≥ of FRmaxFmin of ≥ of VRmaxFmax of ≥ of Vmax of force analysis graph: Vmax -- the oldest rate of linear electromotor, mm/s VRmax -- the oldest rate that feed system asks to achieve, mm/s Fmax -- the biggest thrust of linear electromotor, n FRmax -- the biggest thrust that feed system asks to achieve, n Fmin -- the smallest thrust inside the speed limits that linear electromotor asks in place, n Feff -- the average and effective thrust that feed system place asks, the oldest rate of N linear electromotor calculates by next type: In Vmax=2(1-s)tmax type: S -- slippery difference leads T -- polar distance of linear and dynamoelectric Electromechanical, mm Fmax -- of alternating current source highest and adjustable frequency, if the graph is shown 3 times,system of feed of Hz linear electromotor gets force model. The attrition force FR that when workbench moves, suffers can use next form calculation: In FR=(mg+FAtt)µ type: M -- the total mass of mobile component, kg G -- gravitational acceleration, m/s2 FAtt -- linear electromotor is primary with sub the perpendicular attraction between, n µ -- the force FAcc when the workbench of coefficient of friction of workbench slideway quickens can use next form calculation: In FAcc=ma type: A -- the acceleration that feed moves, m/s2 is inside cycle of a treatment, the Feff of average and effective thrust that feed system place asks can use next form calculation: Feff=[∑ (in type of Fi2ti)]½ ∑ Ti: Fi -- the thrust that asks in place of the system inside a time-interval, n Ti -- time-interval, the time speed-distance curve that S can leave according to typical job circumstance commonly will calculate every time paragraph the FRmax of force of the biggest feed that electromotor asks, and from this the Feff of thrust of average and effective feed that cipher out machines cycle. Again the standard parameter series according to linear electromotor product, will choose to satisfy the linear electromotor that designs a requirement. GD-3 feed unit is 1g, shift for 60m/min, acceleration by rated feed speed quality 33 antimagnetic problem rotates the magnetic field of electromotor closes the interior in electromotor, won't cause any effects to the outside. And the magnetic field of linear electromotor is opened wide, the feed system that uses linear electromotor drive consequently is rigidder to environmental requirement. Use magneto especially when linear electromotor, want to install the permanent magnet with a powerful magnetic force on machine tool lathe bed, because this must take the step that lie between magnetism, otherwise electromotor will grip treatment cuts tool of bits, metal and workpiece mediumly to wait. If these are atomic by the air gap between the stator of inspiratory and linear electromotor and mover in, electromotor will cannot work normally, because this wants the magnetic field of a linear electromotor,use three-dimensional fold formula sealed cover defends rise. GD-3 feed unit uses inductive formula linear electromotor drive, linear electromotor, slideway and lathe bed try to protect with shield of heat-resisting of organ type fold, in order to ensure what electromotor moves is safe. Of linear electromotor medicinal powder linear electromotor installation is in hot issue between workbench and slideway, be in machine tool abdomen, medicinal powder hot difficulty, the efficiency when together with low speed moves is low, calorific amount is large, must take strong cooling step, the quantity of heat of the generation when working electromotor comes loose quickly piece, will affect the working precision of the machine tool directly otherwise, reduce the thrust of linear electromotor. GD-3 feed unit uses the form of dead plate to take away the quantity of heat of electromotor. If the graph is shown 1 times, of linear electromotor primary install instead through a dead plate in the end face inside workbench, sub also go up in base through installation of a dead plate. When the job, the cooling water with constant pressure and discharge is connected in dead plate, in order to is absorbed and take away the quantity of heat of the generation in electromotor coil. The pressure of cooling water and discharge by electromotor primary will decide with sub hot loss. The structural design issue of workbench is straight the athletic component that the workbench of electromotor is unit of high speed feed, the place before be like is narrated, its quality and the biggest acceleration with unit feed become inverse ratio, the acceleration that should increase feed unit must reduce the quality of workbench. For this workbench can choose the light simple stuff of high strenth, alloy of the titanium that be like aluminium, fiber increases plastic etc. Still can use at the same time finite yuan of analysis and the method that optimization devises, move in order to obtain what place asks, the lightest quality below static stiffness condition. The workbench of GD-3 feed unit chooses HT250 cast-iron, use finite yuan the law hardens to the muscle of workbench compose and integral stiffness undertake desired result is mixed optimize a design. Adopt above measure, the quality of workbench reduced 30% ~ than groovy and cast-iron workbench 40% . The choice of slideway structure type moves as a result of linear feed unit rate is high, the slideway when the machine tool works will bear very big move load He Jingzai to carry on one's shoulder or back, get of many sided overturn pitching moment, what the coefficient of friction of slideway still can affect the acceleration of feed system and feed unit is calorific wait, must choose the slideway with high accuracy, tall stiffness, strong carrying capacity consequently. GD-3 feed unit is used " the load such as all directions " slideway of high speed scroll, its coefficient of friction is only 0.

01, and move, static friction coefficient differs smaller, the campaign that uses nicety of this kind of high speed to roll slideway will guide linear electromotor workbench can avoid to give out heat already, can prevent crawl again. The control of unit of feed of 2 linear electromotor does not have any intermediate transmission link between linear electromotor and workbench, consequently system of this kind of feed can use full closed-loop control only. Right now the change of workbench bear, linear electromotor " the effect that carry a department " reach its the change in motion, it is an outside interference to servo. These interference do not have any amortize link, go up to linear servo electromotor with respect to immediate effect. If adjust bad, the function target that may lower a system causes oscillation even. Accordingly, ask its position and tachogenerator have very high resolution and trends to answer ability, the system should have the controller with rash club very strong sex, in order to remove in-house parameter perturbation and the effect that the outside disturbs. System of unit of feed of high speed of the GD-3 of my school linear electromotor uses completely double closed-loop control, core is speed annulus, outer shroud is positional annulus, grating of choice high accuracy surveys a system as the position of feedback link, wait for a method through the error is compensated and adjusting control parameter, better land solved afore-mentioned problems. 3 last words come nearly 10 years, of all kinds and linear electromotor is divided outside applying at numerical control machine tool, already made a lot of unit that have economic value and product, all sorts of machine of coal of machine of machine of the steel tube conveyer that is like linear electromotor drive, crane, pneumatics, punch, drawing, carry, electric braiding machine, dynamoelectric doors, dynamoelectric window. Use the train of magnetism in suspension of linear electromotor drive especially, its speed already exceeded 500km/h, approached the flight rate of aerostat. Linear electromotor regards a kind of of system of feed of numerical control machine tool brand-new drive as means, only weak point history of a few years. At present it is being designed, make and apply a respect to still exist a few problems, cost is higher also, remain to try further thrash out. However its application on machine tool of high speed numerical control, already presented the advantage that gives a series of ball guide screw to be able to not be likened to, already became the new peak that technology of modern world machine tool develops. In recent years, machining center of a lot of new-style high speed that each country rolls out and machine tool of other numerical control, its feed system already used linear motor, hopeful of linear electromotor drive makes the main drive way of machine tool of numerical control of 21 centuries high speed. CNC Milling