Use general lathe treatment to change pitch screw

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  • source:BAGANZ CNC Machining
What the production that uses in the industrial field place such as balata, plastic, food is using all sorts of types widely in equipment is crowded give screw. Change because have,be apart from screw reduce even, compression ratio big, piece makings is successional good wait for an advantage be able to preferential use. But because change,be apart from screw craft sex poorer, use current equipment to machine difficulty, bring about its application to be restricted certainly. The article passes craft analysis, in order to use, mining has current equipment latent capacity to be premise, consider and solved change of pitch screw treatment problem. 1 change the structural characteristic that is apart from screw and craft analysis 1) change the mathematical equation that is apart from screw changes be apart from screw is the screw that photograph adjacent pitch differs. Change commonly usedly if the graph is shown 1 times,spur law of screw pitch change. Graph 1 change be apart from screw sketch map to see from inside the graph, the pitch of screw is arranged by gradual change of arithmetical progression rule. If set dot of the random on helix curve to bit more initiative distance to be L, can get change in be apart from the mathematical equation of screw corkscrewed yarn to be L=nP+n2DP type: P is main pitch; DP is pitch change quantity; N encircles number for corkscrewed yarn, n=f/2p, FP is whorl total corner. N=f/2p era enters equation, l=(P/2p)f+(DP/4p2)f2 makes: A=P/2p, b=DP/4p2, take the place of F=wt again, in getting form of L=Awt + Bw2t2: W is the angular velocity with rotational screw; T has turned for screw the time that F horn place uses. 2) changes be apart from screw curve to analyse A.

Drift analysis is equidistant the mathematical equation of screw is only change one of be apart from screw equation, namely L=Awt curve assumes office to nod axial displacement L and time T easily is a relation; And change be apart from screw L and time T is a relation 2. B.

Speed analysis is become screw divide evenly when fast roll, in the type of bit more aleatoric axial speed V=dl/dt=Aw on equidistant screw corkscrewed yarn: A, W all is constant, reason V is constant, the axial displacement rate that the point moves arbitrarily on equidistant corkscrewed yarn namely is constant. And change the function that the axial rate that the axial speed V=dl/dt=Aw+2Bw2t that is apart from the random on corkscrewed yarn to nod shows to the random on gearshift corkscrewed yarn moves a point is time, be change. C.

Acceleration analyses A=d2l/dt2=0 of acceleration of equidistant screw axial, change be apart from A=d2l/dt2=2Bw2 of screw axial acceleration, the specification nods axial acceleration arbitrarily on equidistant screw corkscrewed yarn for 0, and change be apart from the random on screw corkscrewed yarn to nod axial acceleration to be constant, its rate change is even. That is to say, change the axial displacement that is apart from the random on corkscrewed yarn to nod is added for divide evenly (decrease) fast motion. 3) figuration motion analyses the pitch screw such as treatment, simply main shaft drives workpiece divide evenly fast roll, cutting tool makes axial divide evenly fast shift, can form equidistant corkscrewed yarn. Treatment changes be apart from screw, need main shaft to drive workpiece divide evenly on one hand fast roll, need cutting tool to make axial divide evenly add on one hand (decrease) fast shift ability is formed change be apart from corkscrewed yarn. As general lathe, cutting tool can make axial divide evenly only fast shift, want cutting tool to make divide evenly add (decrease) fast motion, the orgnaization that can realize divide evenly gearshift to move must be added in feed device. 2 change be apart from treatment system design to want implementation to change the treatment that is apart from whorl, in figuration motion, should come true at the same time change the Awt in be apart from whorl equation and Bw2t2 two motion curve. Among them Awt can come true by the function of general lathe itself, and Bw2t2, must come true through adding one auxiliary unit. Classics analysis, quite, the possibility that carries out considering craft, structure at the same time, economy reachs convenient sex, we devised one cam mechanism () of auxiliary feed box. Use cam etc add (decrease) fast curve drives guide screw to make axial divide evenly add (decrease) fast motion, got the figuration contrail ― of pitch whorl changes changing pitch corkscrewed yarn, if pursue 2. Graph 2 change be apart from graph of treatment system principle to cover on one gear in the extreme of general lathe guide screw, deliver the whirligig of guide screw the cam in auxiliary feed box through gear. Driven slide is driven through gearshift curve while cam is turning () of couplet of solid of guide screw axial, drive guide screw to make divide evenly add relative to lathe bed thereby (decrease) fast motion (guide screw and lathe bed but slippage) . Such, this motion and main shaft (drive workpiece) fast roll motion synthesizes divide evenly, can machine piece change be apart from screw. Undertake detecting to designing systematic spot to machine example, data is as follows: Workpiece diameter D=f65 Mm, workpiece length L=1, 900mm, l=1 of whorl overall length, 210.

95mm, whorl counts N=23, pitch increment DP=0.

55mm, pitch comes by 40 ～ gradual change 64.

75mm, pitch is the biggest error ＜ ± 0.

17 Mm. Result proof, what machine whorl to be apart from corkscrewed yarn to change truly, accord with in front the mathematical equation of derivation, satisfy design requirement namely. 3 change be apart from structure of treatment system characteristic simple, adjust convenient, economy practical. According to making an on-the-spot investigation, abroad uses numerical control machine tool and treatment of special machine tool to change mostly be apart from screw, this kinds of advantage that machines a method is: Tall, precision assures 1) efficiency easily; Its defect is: Equipment is complex, costly, process cost is advanced. And what we design change be apart from treatment system, it is to use existing general purpose machine tool, add one texture only the simple, auxiliary feed box that adjusts easily. Change in treatment when be apart from whorl, put through auxiliary feed box, when having groovy treatment, disconnect auxiliary feed box. Such, do not affect the craft range with original machine tool. See this plan economy, practical. 2) changes be apart from limits wide, product standards is much. Those who machine different specifications change be apart from screw, need to adjust auxiliary feed box to be hanged mediumly by the requirement only annulus, change transmission comparing, can change the size that divide evenly gearshift spends cutting tool, can machine a variety of norms consequently change be apart from screw. 3) product quality is good, manufacturing efficiency is tall. With this system treatment changes be apart from screw, operate simple, quality efficiency of stable, production is tall. CNC Milling