Method of treatment of columnar gear tooth form and treatment program (below)

The high speed that shave ages the knife drives workpiece, turn over have a change of luck to move ― to move basically. 2.

Reciprocate of workpiece edge axial - make gear widths over teeth all can shave gives 　 3.

Every move back and forth does work radial feed moves - in order to excise overall surplus. The place on put together is narrated, the process that shave tine machines is shave tine knife and the gear that be cut in teeth of a cogwheel the freedom of double-faced and close together clench the teeth exhibits movement in, realize imperceptible cutting process, and the postulate that realizes shave tine is axes existence an across horn, it is zero hour when alternate horn, cutting speed is 0, shave ages the knife does not have cutting action to workpiece. (2) 　 of shave tine characteristic 1.

Precision of shave tine treatment is 6 ～ commonly 7 class, ra is exterior surface roughness 0.

8 ～ 0.

4 μ M, use at quenching the finish machining of gear. 2.

The productivity that shave tine machines is tall, the gear that machines a medium dimension needs 2 ～ 4 Min only commonly, compare with roll flute photograph, can improve productivity 10 times above. 3.

Because shave ages treatment is free clench the teeth, the machine tool is not had extend athletic drive cable length, structure of reason machine tool is simple, face-lifting of machine tool attune is easy. (3) the 　 of a few problems that makes sure shave ages quality should notice 1.

The treatment requirement 　 to the gear before shave (1) density of material of requirement of material of the gear before shave is even, without local defect, tenacity must not pass big, lest appear,slippery knife is mixed gnaw cut a phenomenon, affect exterior surface roughness. Hardness of the gear before shave is more appropriate inside limits of 32HRC of 22 ～ . (2) precision of the gear before shave ages as a result of shave is " free clench the teeth " , without compulsive cent tine moves, uniformity of reason cent tine is uncontrollable. Because shave fore-tooth circle has radial error, when beginning shave to age, shave tine knife can go up with workpiece only be apart from rotate the tooth profile with further center does the shave that does not have backlash clench the teeth to cut, and turn side having a tooth-like part of anything into clearance with other tine, but cut action without shave right now. Successive and radial feed, other tine is made with tooth gradually without backlash clench the teeth. The radial with tine original as a result group is jumpy decreased, but the positional edge of tooth profile is tangential produced new change, variation of length of public law line increases. Reason shave ages treatment cannot amend variation of length of public law line. Although encircle radial to beat to tine,have stronger correction capacity, but pass to because radial is jumpy,avoid big and cut in shave what length of public law line brings about in the process is farther fluctuant, ask the radial error of the gear before shave cannot pass thereby big. Divide this beyond, shave ages to gear other each error all has stronger correction capacity. The analysis is informed, shave tine amends ability to the error of group of the first public errand weaker, because this asks the athletic precision of gear is before shave,cannot ask under shave hind, especially variation of length of public law line should assure before shave; Each precision can compare other shave hind is low one class. (3) the size of surplus of tine of shave of shave tine surplus, all have certain effect to machining quality and productivity. Surplus is insufficient, blemish of tooth flank of the sum of errors before shave cannot all eliminate; Surplus is too large, cutting tool wears away fast, shave tine quality instead addle. Express 9, the 5 reference when can offerring choice surplus. Express 9 - surplus of 5 shave tine (surplus of tine of Mm) modulus shave 1 ～ 1.

750.

072 ～ 30.

083.

25 ～ 40.

094 ～ 50.

105.

5 ～ 60.

11 　 　 2.

Shave ages the chooses knife of 　 shave tine precision of the knife divides level of A, B, C3, machine respectively 6, 7, the gear of 8 class precision. Shave ages diameter of knife reference circle has 3 kinds along with modulus size: 85 Mm, 180 Mm, 240 Mm, among them 240 Mm application is the most general. Reference circle helix angle has 5 ° , 10 ° , 15 ° 3 kinds, among them 5 ° apply two kinds with 10 ° the widest. 15 ° are multi-purpose at machining gear of straight tine cylinder; 5 ° are multi-purpose the pinion in treatment helical gear and much couplet gear. When shave scarfing gear, axial across φ is unfavorable 20 ° of ～ of more than 10 ° , otherwise shave cuts the result bad. 3.

The gear tooth form after the teeth shape error after shave and tooth profile of shave tine knife repair form shave to age appears sometimes near pitch circle sunken into, if pursue 9 - 13 are shown, be in commonly 0.

03 Mm left and right sides. Be counted to jump over by shave gear tine little, in sunken phenomenon is serious. In be the tooth flank after eliminating shave sunken phenomenon, can write outline of shave tine tooth form, need passes much experimentation ability to decide finally. After gear hobbing of the hob before also can using special shave, undertake shave ages again. 4, the surface of gear teeth of a cogwheel after top gem tine quenchs has oxidation skin, affect tooth flank surface roughness, of heat treatment be out of shape the precision that also affects gear. As a result of workpiece already temper by dipping in water is hard, outside be being machined except usable grinding, but also can use top gem tine to have precision work. Principle of top gem tine and shave tine are similar, top gem annulus and workpiece are similar to gear of a pair of helix to show without backlash clench the teeth, those who use part of clench the teeth is relatively slip, the pressure with bring to bear on constant between tooth flank will undertake the top gem ages. The motion when the top gem ages and shave tine are identical. Namely top gem annulus drives workpiece high speed, retrorse roll, reciprocate of workpiece edge axial and workpiece radial feed move. Radial feed after aging with shave different is to drive arrives book the position, reason tooth flank pressure is greater in the begining, reduce gradually subsequently, till the top gem when pressure disappears tine ends. Top gem annulus by abrasive (normally 180 ＃ of 80 ＃ ～ the electric corundum of granuality) after mixing with the raw material such as epoxy resin, become in core mould. Top gem tine is the method of a kind of finish machining after gear heat treatment. With shave tine photograph is compared, top gem tine has characteristic of the following craft: (1) structure of top gem annulus and grind round of likeness, rate of Dan Hang tine is very low (it is 1 ～ 3m/s normally) , together with wears a size fine, flexibility of top gem annulus is bigger, process of tine of reason top gem is grinding of a kind of low speed, abrade actually the integrated process with polishing. (2) when the top gem ages, teeth directional of edge of tooth flank clearance has outside sliding relatively, direction of edge tooth form also exists slip, consequently tooth flank forms complex reticulation, improved tooth flank quality, its surface roughness but from Ra1.

6 μ M falls Ra0.

8 ～ 0.

4 μ M. (3) flexibility of top gem annulus is bigger, not strong to each error correction action of the gear before the top gem. Accordingly, right the precision demand of itself of top gem annulus is not high, error of top gem annulus won't be mirrorred commonly be gotten on by top gem gear. (4) the oxidation skin on the tooth flank after top gem annulus basically is used at purify heat treatment and burr. The top gem ages surplus does not exceed 0 commonly.

025mm, rotate speed of top gem annulus achieves 1000 R/min above, fore-and-aft feed is 0.

05 ～ 0.

065mm/r. (5) productivity of top gem annulus is very tall, general a minute of top gem one, 5 times through 3 ～ move back and forth can be finished. 5, roll flute roll flute is a kind of method with the at present highest precision in tooth form treatment. It already but grinding not oil hard gear, also but the gear with grinding hard temper by dipping in water. Roll flute precision 6 class of 4 ～ , tooth flank surface roughness is Ra0.

8 ～ 0.

2 μ M. Be out of shape to gear error and heat treatment have stronger correction capacity. Multi-purpose the finish machining that waits for gear cutting tool at gear of high accuracy of hard tooth flank and knife of tine of the knife that insert tine, shave. Its defect is productivity low, finished cost is high, reason applies to sheet pre production. (one) roll flute principle and the methodological formation according to tooth flank involute principle, cent of roll flute method is mixed for copying method extend a law two kinds. Copying method roll flute is to use figuration emery wheel to grind an involute tooth form directly, application is very at present little; Exhibiting law roll flute is the two aspect that control emery wheel working face fictitious rack, give the involute tooth flank of gear through including sth resembling a net with the motion of clench the teeth of workpiece. A few kinds of commonly used roll flute methods introduce below: 1.

Roll flute of cone emery wheel uses method of this kind of roll flute have opportunity of Y7131 and Y7132 roll flute. They are to use the relation of compulsive clench the teeth of fictitious rack and gear to undertake be exhibitinged machining, if pursue 9 - 14 width with because gear has,be shown certain, to grind an all tooth flank, emery wheel still must make reciprocate along gear axial. Axial reciprocate and exhibit athletic union to rise the grinding contrail that makes grind bead to go up in tooth flank, if pursue 9 - 15 are shown. 2.

Double a graph of roll flute of butterfly form emery wheel 9 - show 16 times double a roll flute of butterfly form emery wheel. Roll flute of emery wheel of two butterfly form constitutes two flank of fictitious rack. The emery wheel when roll flute is in only former a circumgyrate (N0) ; Workpiece makes corresponding positive and negative turn (N) and reciprocating translation (V) , form exhibit movement. To grind a workpiece widths over teeth, workpiece still must be made along its axes direction slow fast feed moves (F) . After an alveolar two flank are ground, workpiece exits emery wheel quickly, via the next of the reentrance after graduation the tooth flank of alveolar position is machined. Afore-mentioned become exhibiting motion can adopt a plan 9 - the orgnaization that 16b place shows comes true. The slide carriage in adopting a plan 7 with frame 2, roll disc 3 reach the rounded Pan Gang that metal strip comprises 4 times to take an orgnaization, in order to realize roll of workpiece positive and negative (N) and reciprocating translation (V) cooperate motion. Workpiece is slow fast feed (F) by workbench the shift of 1 is finished. Because method of this kind of roll flute produces the transmission segment that exhibits movement error of catenary of little, drive is small (there is automatic compensation device to give after emery wheel wears away compensation) age with cent precision is tall, reason machines precision to be able to amount to 4 class. But because dish form emery wheel is rigid poor, cutting deepness is lesser, productivity is low, reason finished cost is higher, apply to sheet clench the teeth of pre production China and foreign countries ages continuously and the high accuracy of helical gear is machined. (2) the measure 　 that improves roll flute precision and roll flute efficiency 1. The measure 　 that raises roll flute precision (1) material of emery wheel of logical choice emery wheel chooses Bai Gangyu (WA) , hardness with soft, medium soft advisable. Granuality uses emery wheel to appearance and exterior surface roughness ask and be decided according to place, be in commonly 46 ＃ ～ are chosen inside the limits of 80 ＃ . To worm emery wheel, granuality should be chosen a few more finely. Because its exhibit speed faster, to assure the surface roughness with inferior tooth flank, granuality shoulds not be thicker. In addition, to assure roll flute precision, emery wheel must pass accurate balance. (2) raising machine tool precision basically is the circumgyrate precision that raises workpiece main shaft, if use high accuracy bearing, raise the pitch precision of index plate, reduce its mounting error to wait. (3) use logical craft step to basically have: Undertake operating by procedure; Gear undertakes iteration qualitative processing and temper are handled, in order to eliminate the internal stress of because of leftover stress and machining generation; Raise the precision with fiducial craft, those who reduce aperture and axis cooperate the clearance prejudicial influence to workpiece; Keep apart oscillatory source, prevent foreign interference; The room temperature when roll flute keeps stable, every wear a batch of gear, its difference in temperature is not more than 1 ° C; Careful nap emery wheel, uses diamond must sharp, etc. 2. Of the efficiency of measure roll flute that improves roll flute efficiency rising basically is to reduce knife number, shorten journey length and raise grinding dosage to wait. Commonly used measure is as follows: (1) roll flute surplus wants even, so that reduce knife number effectively; (2) shorten extend length, so that shorten roll flute time. Can use when rough machining without exhibit grinding; (3) use atmosphere aperture emery wheel, in order to increase grinding dosage. 6, the choice of plan of gear cutting of option of gear cutting plan, basically depend on the accuracy class of gear, production lot and heat treatment method. A few principles when gear cutting plan chooses advance below, in order to offer reference: 1.

Reach 8 level to 8 class of the following precision not oil hard gear, usable mill tine, gear hobbing or insert tine to achieve treatment precision to ask directly. 2.

Reach 8 level to 8 class the oil hard gear of the following precision, need to raise precision one level before quench, its machine plan to be able to use: Boil (insert) tine - tine carries treatment - tooth flank temper by dipping in water is hard - amend inside aperture. 3.

To 6 ～ of 7 class precision not oil hard gear, plan of its gear cutting: Gear hobbing - shave tine. 4.

To 6 ～ the oil hard gear of 7 class precision, treatment of its tooth form has two kinds of plan commonly: (1) shave - honing plan boils (insert) tine - tine carries treatment - shave ages - tooth flank temper by dipping in water is hard - amend inside aperture - top gem tine. (2) roll flute plan boils (insert) tine - tine carries treatment - tooth flank temper by dipping in water is hard - amend inside aperture - roll flute. Shave - productivity of top gem program is tall, be used extensively at gear of 7 class precision in be being produced group by group. Productivity of roll flute program is low, use at the gear of above of 6 class precision commonly. 5.

To the gear of 5 class and above of 5 class precision, adopt roll flute plan commonly. 6.

To big batch production, with boil (insert) tine - the treatment program of cold crowded tine, can gain gear of 7 class precision steadily. CNC Milling CNC Machining