Cycle of the protruding when grinding uses the research of gearshift rule

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Home uses having grinder of camshaft of profiling numerical control is costly entrance equipment almost. The cam outline grinding that fast control leaves the numerical control system that the article developed the grinding machine of numerical control camshaft that is control equipment with the PC and software and constant line machines data processing method. Cam grinding is the special grinding that be not a circle. When grinding, besides dispenses of basic circle ministry round grinding machines a state identical, the grinding condition of other part all produces change ceaselessly. Above all, because cam curve is,become by a few kinds of simple or complex curve joining together, bring about cam outline to form campaign thereby discontinuous, speed, acceleration " dash forward jump " acuteness. Next, by the instantaneous career that grinding chooses, the osculatory arc length of emery wheel and workpiece and the appearance that grinding dot all follows cam curve relative to the polar coordinates position at cam center change, make grinding force, emery wheel - the flexibility of workpiece system is out of shape, grinding quantity of heat also produce change ceaselessly. For this, adopt following technology measure. Grinding machines the data processing in the process to all use batten function 3 times to plan to close. 3 times batten function can maintain each model the place that be worth a dot one, 2 rank derivative is successive, each model the value nods a flowing join, make cam rises Cheng curve thereby successive and flowing change, the speed in grinding process, acceleration makes the same score glide to cross. Use gearshift constant to grind except rate control. Make workpiece is in in different grinding point, workpiece rotate speed is different, grinding nods the linear velocity that is in cam outline to keep basically changeless, in order to make sure the process in grinding cam a week is medium, the metal is ground except rate is basic keep changeless, grinding force change is not big, reduce the exterior ripple of cam outline and burn. Use software to compensate a technology. Graph the 1 treatment model when taking no account of emery wheel nap and grinding feed one, before current model machines the maths of linkage coordinate, by conventional input cam number of axle is occupied (camshaft dimension, cam data of number, watch rising Cheng) , cam processes data (feed of grinding surplus, grinding) , emery wheel data (time-interval of nap of quantity of emery wheel nap, emery wheel) , parameter of machine tool system, computation gives the real profile coordinate of cam, grinding to machine linkage coordinate, undertake constant is ground then except rate processing, pass batten function interpolation 3 times, the pulse that interpolation gives of number and servo of pulse frequency input accuse board, and drive servo electric machinery moves, achieve X-C linkage. The machine tool uses form of X-C2 axis linkage to produce cam outline curve, by the polar coordinates of cam real profile nap of radius of value, emery wheel, emery wheel is measured, the maths that the parameter such as grinding feed decides X-C linkage coordinate is general the model sees a picture 1. ρ of foregone cam real profile (φ ) , coordinate fastens XOY to originally to go up on cam center, when grinding, emery wheel and cam outline are contacted up in the law. Graph 1 in O(O) secures datum mark for cam, edge X direction moves back and forth, b dot is emery wheel center. Through I the Rw of emery wheel radius after second nap is: (In 1) type, rw0 is the initiative radius of emery wheel; DRw is emery wheel every time nap quantity; To pass I the emery wheel after nap of second emery wheel is in the decrement of radius direction. Make again: B of center of the emery wheel when considering emery wheel nap and grinding feed is to the distance Sx of cam center O: (2) and cam (C axis) the angular displacement that has turned is: C= φ + β - in type of α A (3) (4) : The cam when ε is encircled currently for grinding most outside outline asks to ideal the ply of outline, for: (In 5) type, for cam grinding total surplus; N always encircles number for grinding; The cam outline ply that after be being encircled for grinding I, grinds. type (5) generation enters type (2) gets cam grinding to machine mathematical model to be: (6) pursues the emery wheel in 2 grinding process inverts 3 indication grinding machine location drawing of area of the grinding when 3 cam grinding simplify 2, model of maths of coordinate of the linkage below fast control condition is in constant line when C axis undertakes grinding with constant rotate speed, because cam outline promotes the constant change of Cheng, the linear velocity that cam outline nods each also changes ceaselessly, those who cause grinding is inhomogenous, the metal in grinding process is ground except rate as change of curve of cam outline face change, cause surface wave of burn, cam to spend thereby. The metabolic rule inside grinding cam a week: Press " basic circle, rise Cheng, peach is pointed, very round, return trip, basic circle " ordinal metal is ground except rate change. Cam width B and grinding deepness Ap all can consider as one changeless quantity, the ω of V of instantaneous linear velocity that dot of reason cam grinding is in decides to grind except rate. Want to control C axis rotate speed only, make V ω is one constant value, can realize constant to grind except rate grinding. The graph shows 3 positions in be grinding process 2 times. Grind inside time T1 except SA1A2B2B1 of cam outline area, grind inside time T2 it is SA2A3B3B2 except cam outline area, ... . Constant is ground except leading is to point to to the metallic bulk that divide is ground inside unit time equal, namely: (7) shows enlarge of A1A2B2B1 of will local district, it is it music parallelogram approximately, if pursue,3 are shown. An edge of the parallelogram (the length of arc A1B1) φ of the D that it is ρ , its are Ap high namely, criterion type (7) melt into: (8) type (8) simplifies further for: (9) by type (9) has: (10) can push from this derive: (In 11) type, k is constant, k ＝ is ground except rate / Apb. Control the rotational rule of C axis from this, implementation gearshift constant is ground except rate control grinding machines cam. CNC Milling CNC Machining