Method of treatment of columnar gear tooth form and treatment program (go up)

The treatment process of a gear is constituted by a certain number of working procedure. To gain the gear that accords with precision requirement, whole treatment process is around wear what working procedure of tooth form treatment serves. Method of tooth form treatment is very much, in pressing treatment, have without cutting, cent is machined to do not have cutting and can cutting machines two kinds big. Without cutting treatment incorporates the new technology such as forge of hot-rolling gear, cold rolling gear, essence, pulverous metallurgy. Without cutting treatment has productivity tall, material spends little, cost low a series of advantage, already popularized at present use. But because its treatment precision is inferior, craft is not quite stable, especially production lot hour is used hard, these defect restricted its use. Dentiform has cutting treatment, have good treatment precision, still be dentiform basically machines a method at present. By its treatment principle can be divided mix for figuration law extend a law two kinds. The characteristic of figuration law is the cutting blade that uses cutting tool appearance and be cut the figure of gear annulus chamfer is same, if pursue,9-3 place is shown. With figuration principle treatment dentiform method has: On milling machine with gear milling cutter mill ages, with roll flute of figuration emery wheel, help the method such as tine with gear broach. Because these methods are put in the mounting error of graduation error and cutting tool, treatment precision is so inferior, can machine the gear that gives 9~10 class precision only commonly. In addition, discontinuous cent a tooth-like part of anything wants in machining a process, productivity is very low also. Accordingly, basically use at sheet the gear with small lot production and not high precision of the treatment in repairing allotment of labour to make. The principle that applies gear clench the teeth will undertake extend a law machining, the line including sth resembling a net that the tooth form outline that with this kind of method treatment comes out is contrail of motion of blade of cutting tool cutting. Tine counts different gear, as long as modulus and tooth form role are same, can use same come to cutting tool machine. With exhibit a principle to machine dentiform method to have: Gear hobbing, insert the method such as tine, shave tine, top gem tine and roll flute. Among them shave tine, top gem tine and roll flute belong to method of dentiform finish machining. The treatment precision that extends a law and productivity are taller, cutting tool versatility is good, aborning application is very so wide. One, gear hobbing 　 (one) the principle of gear hobbing and craft characteristic gear hobbing are the productivity in method of tooth form treatment the method of a kind of treatment with taller, the widest application. The principle of gear is machined with gear hob on gear-hobbing machine, be equivalent to aging to helix the rotate does not have the clench the teeth with mandatory backlash, see graph 9-24 place is shown. The versatility that gear hobbing machines is better, can machine columnar gear already, can machine worm wheel again; Can process involute tooth form already, can process the tooth form such as circular arc, cycloid again; Can machine big modulus gear already, big diameter gear. Gear hobbing can machine gear of 8~9 class precision directly, also can use the rough machining that makes gear of 7 class above and semifinishing machining. Gear hobbing can obtain taller athletic precision, but because the tooth flank when gear hobbing is,become, the tooth number that joins cutting is limited, the exterior surface roughness of tooth flank is consequently thicker. To improve the treatment precision of gear hobbing and tooth flank quality, appropriate parts wide choice gear hobbing. (2) quality of gear hobbing treatment analyses 　 1.

The main reason of the precision of positive drive of influence of machining error analysis of influence drive precision is the hob in be being machined and the relative position of the gear that be cut and opposite movement produced change. The change of relative position (geometry is prejudicial) the radial error that produces gear wheel; The change of opposite motion (motion is prejudicial) those who produce gear wheel is tangential error. (The error of radial of radial error gear of 1) gear is when pointing to gear hobbing, the actual centre of turning circle as a result of tine base is as fiducial as its aperture center not coincide, the Zhou Jie that the teeth of a cogwheel that makes cut gear produces radial deflection and causes accumulates tolerancepublic errand, if pursue 9, 4 are shown. The radial error of gear can age through measuring circle radial beats △ Fr report comes out commonly. The generation when angrily ages the main reason of round of radial error is as follows: When ① adjusts clamping apparatus, arbor and centre of turning circle of machine tool workbench not coincide. ② ages base has space between fiducial aperture and arbor, the deflection when holding clip at the same time. Fixed position of ③ fiducial end panel is bad, the aperture inside clamp hind arises relative to workbench centre of turning circle prejudicial. (Of 2) gear tangential of error gear tangential the error is when pointing to gear hobbing, actual tooth profile is relatively academic positional edge is circumferential direction (tangential) produce displacement, if pursue,9-5 place is shown. Appear when gear tangential when displacement, can change through measuring length of public law line Fw of tolerancepublic errand △ will mirror. Gear of the generation when angrily is tangential the transmission error that the main reason of the error is transmission catenary causes. In the each drive component of catenary of the drive that divide tine, the biggest to transmission error influence is the graduation worm wheel below workbench. In graduation worm wheel is being made and be being installed with workbench centre of turning circle not coincide (motion is prejudicial) , make corner error happens in workbench circumgyrate, and answer mirror gear. Next, the another main factor that affects transmission error is to divide tine to hang annulus make and mounting error, these errors also deliver workbench to go up with larger proportion. 2.

The Ff of △ of teeth shape error that the main factor that the machining error analysis that affects gear job to make the same score stability affects positive drive job to make the same score stability is gear and Fpb of △ of base pitch deviation. Teeth shape error can cause the instantaneous change that the drive in process of clench the teeth of every pairs of gear compares; Base pitch deviation can cause the mutation that transfers to age to another pair the drive when clench the teeth is compared to tine. Positive drive changes to produce noise and vibration with mutation than instantaneous as a result of transmission, affect the job to make the same score stability precision thereby. When gear hobbing, the base pitch error that produces gear wheel is minor, and teeth shape error normally bigger. Undertake discussion respectively below. (1) because the production blade of gear hob grinds the reason such as the mounting error of error and hob to cause,teeth shape error of teeth shape error basically is, because this is in,the each in turning metropolis of hob is mirrorred to tooth flank. What common teeth shape error is like graph 9-6 place to show is multiform. E of the periodic error that graph A gives B of arris, graph to be D of error of tooth form horn, graph to go up for tooth flank for C of tooth form asymmetry, graph for tooth flank, graph is gear root to cut. The tooth flank deviate as a result of gear correct involute, make drive of the instantaneous in positive drive is compared not stable, the work that affects gear makes the same score stability. (When gear hobbing of extreme deviation of 2) base pitch, the base pitch extreme deviation of gear basically suffers the effect of deviation of hob base pitch. Type of hob coxal computation is: 0 ≈ of α of 0cos of Pb0=pn0cos α 0=pt0cos λ 0 　 of Pt0cos α in type: Pb0 -- hob base pitch; Pn0 -- hob law to pitch; Pt0 -- hob axial pitch; α 0 -- hob law to tooth form horn; λ 0 -- helix of hob reference circle promotes role, general very small, because of this Cos λ 0 ≈ 1. By go up form is visible, to reduce base pitch deviation, when hob is made, answer to control axial pitch and error of tooth form horn strictly, be opposite at the same time the blame of face of the knife before the tooth that affects error of pitch of axial of sum of errors of tooth form horn is radial sexual error also should try to control. 3.

The osculatory situation that the machining error that affects gear to contact precision analyses gear tooth flank affects the uniformity that the load in positive drive distributings directly. When gear hobbing, the contacts precision main reason that affects tooth depth way is Ff of △ of tooth form public errand and Fpb of △ of base pitch extreme deviation. The contacts precision main reason that affects facewidth way is β of F of △ of teeth directional public errand. Produce the main reason of teeth directional public errand: (1) photograph of slideway of gear-hobbing machine tool carrier exists to workbench circumgyrate axes parallelism alignment error, if 9 ― are shown 7 times. (2) clip of tine base outfit is askew because base of arbor, tine is standard end panel is jumpy reach washerbed down the livestock the rough travel tine base that cause installs two end panel askew, can produce teeth directional error, if pursue 9 - 8 are shown. (3) when rolling cut helical gear, outside removing afore-mentioned influencing factor, machine tool differential hangs round of calculative error, also can affect the teeth directional error of gear. 4.

The way 　 that improves gear hobbing productivity (1) high speed gear hobbing in recent years, our country already began design and gear-hobbing machine of production high speed, at the same time production gives aluminous high-speed steel (MO5Al) hob. Gear hobbing rate rises V=100m/min above by general V=30m/min, axial feed F=1.

38mm/r ～ 2.

6mm/r, make productivity rises 25% . Abroad already raised 150 M/min of 100 M/min ～ with speed of gear hobbing of high-speed steel hob; Hard alloy hob already experimented 400 M/min above. Anyhow, high speed gear hobbing has certain development outlook. (2) use bull hob to be able to improve productivity apparently, but treatment precision is inferior, tooth flank is coarse, consequently multi-purpose in rough machining. When gear cutting precision when the demand is higher, can use big diameter hob, make attend the tooth number that extends exercise to increase, surface roughness of treatment tooth flank is fine. (3) improve gear hobbing to machine methodological 　 A. Many treatment strings together base of a few tine outfit machine on arbor, can reduce hob to age to every of base cut cut a time to reach assemble and unassemble time. B.

The method that uses the hob when radial cuts gear hobbing to cut tine semifinished product has two kinds: Radial is cut cut with axial. Radial is cut cut journey weak point than axial, can save cut time, to be being highlighted particularly when gear hobbing of big diameter hob. C.

The tooth bear that uses axial change knife and hob of diagonally gear hobbing to participate in cutting differs, wear away not all, when bear the heaviest tooth wears away when certain level, should move hob along its axial a paragraph of distance (namely axial change knife) succeed add cutting, in order to improve the service life of cutting tool. Diagonally gear hobbing is hob in feed of axial of edge tine base while, axial of arbor of the hob that return an edge moves continuously, the synthesis of two kinds of motion, make tooth flank forms diagonal knife mark, reduced tooth flank surface roughness not only, and make tooth wears away even, raised the service life of cutting tool and durability, if pursue 9 - 9 are shown. 2, the 　 that insert tine (one) the principle that insert tine and athletic 　 1. The principle that insert tine is analysed from the principle of the process that insert tine, if pursue 9 - 10 are shown, the clench the teeth of columnar gear photograph that inserts tine knife to be equivalent to one mutual to axes parallel. The knife that insert tine grinds the gear wheel that have around part and has cutting blade namely essentially. 2. The main movement that inserts tine has: (1) cutting motion inserts tine knife go up, next reciprocate. (2) cent tine exhibits motion to insert the relationship of clench the teeth that should keep correct between tine knife and workpiece. Insert tine knife move back and forth, the arc length that workpiece has turned on reference circle relative to cutting tool is the circumferential feed when treatment, the process of clench the teeth of reason cutting tool and workpiece namely circumferential feed process. (3) when radial feed motion inserts tine, come to be cut stage by stage complete tine is deep, the knife that insert tine is due radial feed Fr. (4) when motion letting a knife inserts tine knife to make fluctuation reciprocate, it is cutting journey downward. Wear away to avoid what the tooth flank that cutting tool abrade already machined reduces tooth, when inserting tine knife to move up, workbench drives workpiece to quit cutting division a paragraph of distance (radial) . When journey of job of the knife that insert tine, workbench restores again former. (2) the craft characteristic that inserts tine inserts tine and gear hobbing photograph to compare, machining quality, the respect such as productivity and applied limits has its characteristic. 1.

The treatment quality 　 that inserts tine (1) when the tooth form precision that inserts tine compares gear hobbing tall gear hobbing, the head number of the number that forms tooth form to wrap the tangent amount of line of subsidiary channels in the human body through which vital energy to allow bits chamfer with hob only and basic worm is concerned, it cannot machine a condition through the change and increase and decrease; But when inserting tine, the tangent amount that forms tooth form to include line of subsidiary channels in the human body through which vital energy is decided by the size of circumferential feed, can choose. In addition, it is approximate formative worm will replace involute when production gear hob basic worm, this has shaping error. And the tooth form of the knife that insert tine is simpler, can win exact involute tooth form through high accuracy roll flute. Insert tine to be able to get taller tooth form precision so. (2) the surface roughness of the tooth flank after inserting tine is finer than gear hobbing because,this is when gear hobbing, hob makes discontinuous cutting on teeth directional direction, if pursue,form 9 - the scale account that 11a place shows is moire; And the cutting that direction of teeth directional of tine knife edge inserts when inserting tine is successive, if pursue 9 - 11b place is shown. Surface roughness of the tooth flank when inserting tine so is fine. (3) because plug the transmission chain of tine machine,the athletic precision that inserts tine differs this than gear hobbing is more than gear-hobbing machine worm wheel of a cutting tool deputy, namely much one part transmission error. Additional, a tooth of the knife that insert tine is corresponding one of cutting workpiece alveolar, accordingly, the Zhou Jie of itself of the knife that insert tine accumulates an error to be able to be mirrorred to workpiece necessarily. And when gear hobbing, each because of workpiece alveolar it is by the 2 ～ with identical hob 3 tooth treatment comes out, the pitch of reason hob accumulates an error to be not affected by the pitch precision of treatment gear, so the athletic precision of gear hobbing is compared insert tooth depth. (4) the teeth directional error when the teeth directional error that inserts tine inserts tine greatly than gear hobbing basically decides to age at inserting axes of circumgyrate of machine main shaft and workbench rotor the parallelism alignment error of the line. The frequency of the reciprocate when working as a result of the knife that insert tine is tall, make between main shaft and sleeve wear away big, the teeth directional error that because this is inserted,ages is bigger than gear hobbing. Machine precision so for, not high to athletic precision requirement gear, can use directly insert tine to have tooth form precision work, and the gear before higher to athletic precision requirement gear and shave (shave tine cannot raise athletic precision) , use gear hobbing relatively advantageous. 2. When the productivity that inserts tine cuts patternmaking to count larger gear wheel, the speed that insert tine should be inserted reciprocate of tine knife main shaft inertial restrict rigidly with the machine tool; Cutting process has the time loss of light locomotive trip again, reason productivity is not as tall as gear hobbing. Machining only small modulus, much tine is counted and when the gear with narrower facewidth, the productivity that inserts tine just ages than boiling tall. .

3. Roll the applied range that plugs tine: (1) the double couplet with the gear that treatment contains stage shoulder and very narrow undercut or much couplet gear, can use only insert tine. Because,this is: The knife that insert tine " cut " when need very little space only, and hob of gear hobbing criterion can produce interference with big diameter place. (2) the double-helical gear that treatment does not have undercut, can use only insert tine; (3) machine internal gear, can use only insert tine. (4) machine worm wheel, can use gear hobbing only. (5) gear of cylinder of treatment inclined tine, both is usable. But gear hobbing is more convenient. Insert when making helical gear, the beard on the cutter spindle of the machine that insert tine sets helix slideway, the helix that will offer the knife that insert tine moves, and should use special inclined tooth insert tine knife, so very no-go. (3) the way 　 that improves the productivity that insert tine 1.

Raise circumferential feed to be able to reduce motor-driven time, but the quantity letting a knife when circumferential feed and idle stroke becomes direct ratio, accordingly, must solve the problem letting a knife of good cutting tool. 2.

Grab bed latent capacity increases number of journey of move back and forth, use high speed to insert tine. Some machine that insert tine are minutely time of travel of move back and forth can amount to 1200 ～ 1500 times / Min, highest can achieve 2500 times / Min. Than raising 3 ～ commonly usedly 4 times, make cutting rate rises greatly, also can reduce the motor-driven time that the place that insert tine needs at the same time. 3.

Improve cutting tool parameter, raise the durability of the knife that insert tine, sufficient play inserts the cutting function of tine knife. If use W18Cr4V to insert tine knife, cutting speed can achieve 60m/min; The part before increasing comes 15 ° , part comes 9 ° after, can raise durability 3 times; Advanced knife face grinds a 1 ～ 1.

The platform with wide 5 Mm, also can raise durability 30% the left and right sides. CNC Milling