Character of trends of servo feed system improves measure

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Summary: The effect that the article analysed guide screw pitch, drive to compare change to match to the acceleration of feed system and inertia. Keyword: The feed system that transmission matchs numerical control machine tool than feed acceleration inertia is main by servo electric machinery, main transfer machinery (synchronous drive belt, disappear unoccupied place gear, accurate shaft coupling) , measurement unit of ball guide screw, place (grating feet) composition, it is very important that its trends character machines efficiency and precision to the machine tool, feed acceleration, inertia matchs is two when measure character of feed system trends main index. One, fast (carry for nothing) the computation of torsion of output of the electric machinery when starting: In type, fast sky carries the electric machinery when starting to output torsion, nm; , the electric machinery when fast feed outputs empty Zai Yun torsion, nm, see pattern (2) ; , convert arrives the total laden inertia on electric machinery axis, kg · M2, see pattern (3) ; , the angular acceleration that electric machinery rotates, rad/s2, see pattern (4) . 1, torsion of output of the electric machinery when fast feed calculates empty Zai Yun as follows: In type, attrition torsion, include the attrition torsion of the bearing in feed system and nut, sealed torsion, nm; , axial load, include all sorts of add axial force, slideway attrition power, n; , guide screw lead, mm; , the efficiency of guide screw drive when quickening; , transmission comparing. 2, total laden inertia [1] : In type, the moment of inertia of itself of electric machinery axis, include electric machinery rotor and brake moment of inertia, kg · M2; , electric machinery axis carries drive moment of inertia, include electric machinery axis to carry axis of shaft coupling moment of inertia, electric machinery to carry moment of inertia of transmission spare parts, kg · M2; , itself of ball guide screw reachs his to prop up bearing moment of inertia, kg · M2; , axis of ball guide screw carries drive moment of inertia, include guide screw to carry shaft coupling moment of inertia, guide screw to carry moment of inertia of transmission spare parts, kg · M2; , transmission comparing; , mobile component quality, kg; , guide screw lead, mm. 3, the angular acceleration of guide screw and electric machinery: The concern of the angular acceleration that the linear displacement acceleration of mobile component and guide screw rotate is as follows: In type, the angular acceleration that guide screw rotates, rad/s2; , the linear displacement acceleration of mobile component, m/s2. The linear displacement acceleration of the angular acceleration that electric machinery rotates and mobile component concerns as follows: 2, of servo electric machinery choose reach the analysis that improves dynamic character: 1, electric machinery of the servo in system of feed of test and verify is chosen appropriate, basically consider the following aspects: (The torsion of the need when 1) rough machining is not more than the successive output torsion of servo electric machinery, if feed speed (namely the rotate speed of electric machinery) inferior, this value can be close to rated torsion. (The peak value torsion of 2) servo electric machinery wants to be able to satisfy feed system sky to carry the need that starts quickly, feed system quickens the duration of peak value torsion that time allows at servo electric machinery not quite. (3) inertia matchs. Popularly, convert arrives of the laden moment of inertia on electric machinery axis and moment of inertia of oneself of servo electric machinery than be between 1-3, this specific value is less, criterion it is better that the trends of feed system answers character. (Rotate speed of electric machinery of the servo when 4) moves quickly does not exceed his rated and top rotate speed. 2, the method that raises dynamic character: (1) change drive is compared, guide screw pitch keeps changeless. Pass afore-mentioned formula to be able to see, increase transmission comparing, inertia matchs can have clear improvement; Right now output of servo electric machinery turns the function that be apart from is transmission comparing, can guide through begging get the least best drive is compared making to output turning is apart from. But do not change pitch to increase transmission comparing only, want to make sure mobile component is fast and changeless, criterion rotate speed of electric machinery output should rise. Use the method that adds transmission to improve character of feed axis trends than coming to apply to laden inertia normally the circumstance that electric machinery of very big, servo outputs rotate speed to did not reach rated rotate speed, develop property of power of servo electric machinery function, adequately through increasing transmission to match than can improving inertia, raise feed acceleration. (2) increase transmission comparing, increase pitch at the same time. Inertia matchs function to be able to get ameliorative, rotate speed of electric machinery output is basic and changeless, output turns be apart from reduce, can raise feed acceleration further so. This kind improves the main reason that can improve feed performance is: When pitch of certain, guide screw increases the linear displacement acceleration of mobile component, the angular acceleration of guide screw is reduced, achieve identical move quickly rotate speed of the guide screw when speed also is reduced, namely guide screw is added (decrease) the place when fast roll process is medium needs power input to decrease. Those who need an attention is: Increase as what transmission compares normally, electric machinery axis carries drive axis of guide screw of moment of inertia, ball carries drive moment of inertia also can increase, namely convert arrives the function that the total laden inertia on electric machinery axis is transmission comparing (the fluctuant rate that pitch of hypothesis guide screw and drive compare is same, but circle of need of guide screw pitch is actually full to series of standard) , can guide through begging or iteration gets making the least best drive is compared. Normally this kind alters apply to guide screw moment of inertia to take the case with laden inertia larger proportion. CNC Milling CNC Machining