CN1310730C - Free cutting hobbing for stepped end - Google Patents

Abstract

The present invention relates to a free cutting step end hobbing which comprises a hobbing body, a hobbing rod and hobbing teeth. The free cutting ladder hobbing is characterized in that 1 to12 groups of hobbing teeth are installed, each group at least is provided with two hobbing teeth, the main deflection angles Kr1 of the first step knife teeth of each group of hobbing teeth are equal, the main deflection angles Krm of the hobbing teeth of other steps are different from the main deflection angles Kr1, and the main deflection angles Krm are increased following the increase of m in sequence. The relation between the hobbing radius at the hobbing tip for the hobbing teeth in each step of each group and the distance to the end face of the hobbing body can be any of two following relations that the hobbing radius of all hobbing teeth is equal, the hobbing tips of the hobbing teeth of the first step of each group of hobbing teeth are all positioned in the same plane which is vertical to an axial line of the end hobbing, and the distance of the hobbing tip of the mth hobbing tooth of each group of hobbing teeth to the plane is increased following the increase of m in sequence; the hobbing tips of all hobbing teeth are all positioned in the same plane which is vertical to the axis line of the end hobbing, and the hobbing radius R0m of the mth hobbing tooth of each group of hobbing teeth is increased following the increase of m in sequence. The step end cutting hobbing has the advantages of high efficiency and long service life.

Description

Free cutting hobbing for stepped end

Technical field

The present invention relates to a kind of stepped end.

Background technology

Along with major technologies and equipment develops to large-scale, big capacity, high parameter, high efficiency direction, big part and super large spare process technology have also obtained corresponding development.Show that according to various countries' statistics in the machining of big part, slabbing processing accounts for more than 60% of machining workload, and requires more and more higher to high milling efficiency and low processing cost etc.In order to solve the common problem that major technologies and equipment is made, the heavy-duty face mill that development is fit to milling steel-casting and forging blank is very necessary.

In the Milling Process that heavy-duty machinery is made, because casting, the forging blank surplus is excessive, have greatly to 200 millimeters, with staying defectives such as rough chilling layer behind burning into sand, slag inclusion, cast gate and the rising head gas cutting, add man-hour with existing stepped end, Milling Force and milling temperature height are very big to the durability influence of cutter.Simultaneously, the Milling Force fluctuation is big, and point of a knife is easy to breakage.Because the blank quality of casting, forging is poor, so production efficiency is low, the process-cycle is long, the processing cost height.

Discover for many years through the applicant, existing stepped end, the tool cutting edge angle of each rank cutter tooth equates that the residing radius of the point of a knife of same order cutter tooth is not with highly different, the ladder of its milling figure such as stair shape are referring to Fig. 1.The point of a knife of its each rank cutter tooth not only all carries out cutwork, scrapes and rubs but also gnaw on the surface of work hardening, has quickened the wearing and tearing of point of a knife, seriously has influence on the service life and the milling efficiency of end mill(ing) cutter, so service life is short, milling efficiency is low.

Summary of the invention

In order to overcome existing stepped end quick abrasion short deficiency in service life, the invention provides the stepped end of a kind of milling efficiency height, long service life.

Starting point of the present invention is the point of a knife and the active length that increases cutting edge of this group cutter tooth of protection as-machined workpiece surface.Protection point of a knife best bet is only to allow main cutting edge participate in cutting.The point of a knife that overcomes existing each rank cutter tooth of stepped end cuts on the machined surface of oneself and gnaws and scrape, and can divide bits automatically.Then free cutting becomes the theoretical foundation of shelling powerful end mill(ing) cutter cutting-tool engineering from flight.Experimental study shows, under equal machining condition, and about 1/2 the when cutting temperature during 45 ° of cutter tool cutting edge angles is 90 °; Free cutting is lower by 60%～70% than the cutting temperature of non-free cutting, and cutting force is low more than 30%, and tool life is high by 50%～60%.

This free cutting hobbing for stepped end is identical with the basic structure of common stepped end, and it comprises cutter hub, knife bar, installs on each knife bar or is welding a cutter tooth, and knife bar is installed on the cutter hub.Technical scheme of the present invention is that two or more cutters tooth are installed on the cutterhead of common end milling cutter is many groups cutter tooth of one group, each cutter tooth in every group be called the first rank cutter tooth, the second rank cutter tooth ..., the tool cutting edge angle K of each cutter tooth in every group _rDifference, the tool cutting edge angle minimum of the first rank cutter tooth wherein, the tool cutting edge angle maximum of last rank cutter tooth.K _R1＜K _R2＜K _R3＜K _R4＜K _R5, the tool cutting edge angle K of the first rank cutter tooth wherein _R1Selected by the designer, for example 45 °, 50 °.Have only the point of a knife and the cutting edge of last rank cutter tooth to work simultaneously during milling, other rank cutter tooth has only the cutting of straight line main cutting edge, and point of a knife does not participate in cutting.Thereby the point of a knife that has only last rank cutter tooth is stressed, wearing and tearing, and the point of a knife of the cutter tooth on other rank does not stress and do not wear and tear yet.When adopting indexable structure, after the corner wear of rank, end cutter tooth, can change to the blade of last rank cutter tooth in the cutter groove of first rank or cutters tooth such as second rank, the 3rd rank, the blade of the first rank cutter tooth or the second rank cutter tooth is changed to continued in the cutter groove of last rank cutter tooth to use, thereby obviously improve the utilization rate of cutting edge, increased the service life of each cutter tooth.

The stepped end of the present invention not installation position of tool tip of same order cutter tooth divides contour diameter unequal and unequal two major types of equal diameters height.Their milling figure is referring to Fig. 2.

According to the installation difference of cutter tooth, discuss in two kinds of situation.

The A point of a knife is on the identical diameter of end mill(ing) cutter, and the height of the relative cutterhead end face of point of a knife is unequal.As the tool cutting edge angle K that has determined the first rank cutter tooth _R1, back engagement of the cutting edge is milling depth a _p, back engagement of the cutting edge etc. score value N, every group of amount of feeding a _FzAfterwards, a wherein _FzEqual feed engagement a _fWith every group in cutter tooth count the product of m, second, third ... the tool cutting edge angle of m rank cutter tooth can be respectively variously determined by following:

$\mathrm{tg}{\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="C20041006451700151.png,C20041006451700161.png"\; state="\{\{state\}\}">r</figure-callout>}2}=\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{ct}{\mathrm{\&kappa;}}_{r1}-a_{\mathrm{fz}}}---\left(1\right)$

$\mathrm{tg}{\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="3"\; label="r"\; filenames="C20041006451700133.png,C20041006451700151.png"\; state="\{\{state\}\}">r</figure-callout>}3}=\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{r2}-a_{\mathrm{fz}}}---\left(2\right)$

$\mathrm{tg}{\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="C20041006451700151.png"\; state="\{\{state\}\}">r</figure-callout>}4}=\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{r3}-a_{\mathrm{fz}}}---\left(3\right)$

$\mathrm{tg}{\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="5"\; label="r"\; filenames="C20041006451700151.png,C20041006451700161.png"\; state="\{\{state\}\}">r</figure-callout>}5}=\frac{\frac{a_p}{n}}{\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{r4}-a_{\mathrm{fz}}}---\left(4\right)$

General formula is $\mathrm{tg}{\mathrm{\&kappa;}}_{\mathrm{rm}}=\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{ctg\&kappa;u}-a_{\mathrm{fz}}}---\left(5\right)$

m＝2、3、4、…… u＝m-1

For ease of calculating, above-mentioned (1) to (5) formula is expressed as with angle respectively:

${\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="C20041006451700151.png,C20041006451700161.png"\; state="\{\{state\}\}">r</figure-callout>}2}=\mathrm{arctg}\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{r1}-a_{\mathrm{fz}}}---(1`)$

${\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="3"\; label="r"\; filenames="C20041006451700133.png,C20041006451700151.png"\; state="\{\{state\}\}">r</figure-callout>}3}=\mathrm{arctg}\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{crg}{\mathrm{\&kappa;}}_{r2}-a_{\mathrm{fz}}}---(2`)$

${\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="C20041006451700151.png"\; state="\{\{state\}\}">r</figure-callout>}4}=\mathrm{arctg}\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{r3}-a_{\mathrm{fz}}}---(3`)$

${\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="5"\; label="r"\; filenames="C20041006451700151.png,C20041006451700161.png"\; state="\{\{state\}\}">r</figure-callout>}5}=\mathrm{arctg}\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{r4}-a_{\mathrm{fz}}}---(4`)$

General formula is ${\mathrm{\&kappa;}}_{\mathrm{rm}}=\mathrm{arctg}\frac{\frac{a_p}{N}}{\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{\mathrm{ru}}-a_{\mathrm{fz}}}---(5`)$

m＝2、3、4、…… u＝m-1

Among formula (1`), (2`), (3`), (4`), (5`), for each m value k _RmOnly get first.

When this stepped end of design, determine that earlier the height of the relative cutterhead end face of the first rank cutter tooth point of a knife is H ₁For example, H for example ₁=20 millimeters, the difference in height of facing mutually between each rank cutter tooth point of a knife is pacified following various calculating respectively:

$H_{1-2}=[\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="C20041006451700151.png,C20041006451700161.png"\; state="\{\{state\}\}">r</figure-callout>}2}+a_{\mathrm{fz}}(1-\mathrm{tg}{\mathrm{\&kappa;}}_{r2})]\mathrm{tg}{\mathrm{\&kappa;}}_{r1}---\left(6\right)$

$H_{2-3}=[\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="3"\; label="r"\; filenames="C20041006451700133.png,C20041006451700151.png"\; state="\{\{state\}\}">r</figure-callout>}3}+a_{\mathrm{fz}}(1-\mathrm{tg}{\mathrm{\&kappa;}}_{r3})]\mathrm{tg}{\mathrm{\&kappa;}}_{r2}---\left(7\right)$

$H_{3-4}=[\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="C20041006451700151.png"\; state="\{\{state\}\}">r</figure-callout>}4}+a_{\mathrm{fz}}(1-\mathrm{tg}{\mathrm{\&kappa;}}_{r4})]\mathrm{tg}{\mathrm{\&kappa;}}_{r3}---\left(8\right)$

$H_{4-5}=[\frac{a_p}{N}\mathrm{ctg}{\mathrm{\&kappa;}}_{\mathrm{<figure-callout\; id="5"\; label="r"\; filenames="C20041006451700151.png,C20041006451700161.png"\; state="\{\{state\}\}">r</figure-callout>}5}+a_{\mathrm{fz}}(1-\mathrm{tg}{\mathrm{\&kappa;}}_{r5})]\mathrm{tg}{\mathrm{\&kappa;}}_{r4}---\left(9\right)$

General formula is

H _m-n＝H _n-H _m (11)

m＝1、2、3、4、……， n＝m+1

A in the above-mentioned formula _pFor back engagement of the cutting edge N is that back engagement of the cutting edge is the isodisperse of milling surplus

N=2m or N=2m+1.

All the other cutters tooth have been realized free cutting except that last rank cutter tooth is last cutter tooth of every group of cutter tooth, promptly have only a main cutting edge to participate in cutting, and point of a knife and front cutting edge are not participated in cutting.

Be example with two ladders still, referring to Fig. 8, the point of a knife of the first ladder cutter tooth is by A among the figure ₁Moved on to the C point.In order to protect point of a knife, the C point should be at the step place.Simultaneously, for the ease of measuring and adjusting, the point of a knife of the first rank cutter tooth is placed the D point of the same diameter of the second rank cutter tooth point of a knife.Though milling figure and ladder position alternate with each other that Fig. 8 and Fig. 5 form do not change, the first rank cutter tooth has thoroughly been realized free cutting.

The B point of a knife is contour and point of a knife is on the different radii of end mill(ing) cutter

The tool cutting edge angle K of the first rank cutter tooth _R1Still selected by the designer, two, three, four ... m rank tool cutting edge angle still by algebraic expression (1) to (4) ... determine.If the radius of each rank cutter tooth point of a knife is respectively R ₀₁, R ₀₂, R ₀₃, R ₀₄, R ₀₅... R _m, and R ₀₁＜R ₀₂＜R ₀₃＜R ₀₄＜R ₀₅...＜R _{0 (m-1)}＜R _m, and 2R ₀₁Choose by normal diameter series, for example d ₀=2 R ₀₁,=100,125,160,200 ... 2000, common ratio is 1.25.Semidiameter Δ R between the adjacent two rank cutters tooth (R for example ₀₃-R ₀₂) be the amount of feeding a of every group of cutter tooth _Fza _FzEqual each cutter tooth feed engagement a in the group _fSum.

$2R_{0m+1}=2R_{0m}+2_{a_{\mathrm{fz}}}$ m＝1、2、3、…… (12)

For the ease of understanding, at first use the accurate free cutting of milling picture specification of different tool cutting edge angle end mill(ing) cutters and the formation of special cutting lay.Fig. 3, Fig. 4 are respectively that the tool cutting edge angle of the second rank cutter tooth equals and the milling figure during less than 90 °.The tool cutting edge angle of the first rank cutter tooth is respectively

$\mathrm{tg}{\mathrm{\&kappa;}}_{r1a}=\frac{a_p}{a_{\mathrm{fz}}}---\left(13\right)$

$\mathrm{tg}{\mathrm{\&kappa;}}_{r1b}=\frac{\mathrm{AC}}{\mathrm{AD}}=\frac{a_p}{a_{\mathrm{fz}}+\mathrm{AB}}=\frac{a_p}{a_{\mathrm{fz}}+a_p\mathrm{ctg}{\mathrm{\&kappa;}}_{r2b}}---\left(14\right)$

A in the above-mentioned formula _p-back engagement of the cutting edge (mm); a _Fz-every group amount of feeding

The part of Fig. 3 and Fig. 4 acceptance of the bid "+" number is the metal level of the first rank cutter tooth milling, mark " section oblique line " be the metal level of the second rank cutter tooth milling.Though Fig. 3, milling figure shown in Figure 4 have reached " wheel cut " to strengthen the amount of feeding and to reduce the purpose that the first rank cutter tooth point of a knife is loaded, Fig. 5 was more reasonable when back engagement of the cutting edge was big.As seen from Figure 5, the first rank cutter tooth has excised the part material that the second rank cutter tooth should be cut (as the Δ GEF among the figure) in advance, and and then the second rank cutter tooth has excised the part metals that the first rank cutter tooth should be cut (as the Δ DGE among the figure) again in advance.The area of the first rank cutter tooth milling metal material equates with the area of the second cutter tooth milling metal material, and has formed the ladder milling.The position of its ladder replaces, and this and common stepped end form constant ladder essential distinction.By operating position Fig. 6, Fig. 7 of Fig. 5 and cutting edge as can be known, the workload of this end mill(ing) cutter first rank cutter tooth point of a knife is very little, and near the cutting edge it is not participated in cutting, thus during cutter tooth cutting of this rank very near free cutting.Among Fig. 5, N=3, the milling area of two rank cutters tooth equates that we claim that this cutting image is the optimized cutting figure.Among Fig. 9, N=4, the milling area of the first rank cutter tooth is less, and cutting load is reduced, and helps cutting the workpiece that there is shortcoming on sclerderm or top layer.Be not difficult to find out that when surface of the work was abominable, it was good that N gets even number; To get odd number be good to N when surface of the work hardness was low.The milling figure that Figure 10 is three ladders when flight is shelled powerful end mill(ing) cutter N=5.The first rank cutter tooth and the second rank cutter tooth cutting width are bigger, and point of a knife is also cut less than machined surface, and load is also little even point of a knife switches to machined surface when contour, so this cutting image can be regarded the best as.The design quadravalence above when stepped end, its principle is with above-mentioned identical.

During use, should note following 4 points:

During 1 best milling graphic designs, should rationally choose back engagement of the cutting edge equal portions value N.Method is N=2m or N=m-1, and wherein m is the exponent number of cutter tooth, when workpiece surface quality is relatively poor, gets N=2m, when workpiece surface quality is better, gets N=2m-1.

All cutter groove depths are convenient to the manufacturing of cutterhead and the installation of cutter tooth radially all consistent on the cutterhead of 2 stepped ends.

The cutter tooth of 3 stepped ends is divided into welded type, indexable formula structure.

The indexable insert tip, throw away tip of 4 different tool cutting edge angles because of its blade operating position difference, after milling a period of time, can be changed to and continue cutting on the knife bar of other tool cutting edge angle.

End mill(ing) cutter of the present invention is not only applicable to the slabbing processing of manufactory's Big Steel Castings such as heavy-duty machinery, mining machinery, national defence, shipbuilding, rolling stock, forging, and is applicable to for example slabbing processing of lathe base etc. and less surplus workpiece (as weaving loom dragon wallboard) of other standard machinery manufactories.

Advantage of the present invention is:

(1) tool life height:, improved shock proof ability of whole cutter tooth and cutter life because this end mill(ing) cutter has not only been protected point of a knife and near the cutting edge of point of a knife, and has improved the stressed position and the radiating condition of cutter tooth; (2) blade utilization rate height: when adopting indexable or modular construction, the blade of same order cutter tooth or cutter piece can not exchange, thereby are convenient to make full use of the whole piece cutting edge, make it can save the cutter material expense again than common stepped end, and what have reaches more than 1/3; (3) productivity ratio height: milling efficiency is about two times of common stepped end milling efficiency; (4) Milling Force is low: Milling Force is lower more than 30% than common stepped end, also can increase economic efficiency by energy-conservation; (5) low cost of manufacture: in tooling system, screw, edge bearing, blade etc. belong to standard component.Cutterhead from stepped end is much simpler than the cutterhead processing technology of common stepped end, and manufacturing expenses can reduce by 1/4.In addition, the cutterhead versatility is good, and adorning the identical cutter tooth of several tool cutting edge angles less just becomes common end milling cutter or common powerful end mill(ing) cutter, and filling the identical cutter tooth of tool cutting edge angle just becomes closed teeth end milling cutter, and this also is the essential condition that reduces the cost of charp tool.Cutter hub that reaches for diameter such as diameter can be installed 12 groups or 12 groups of above cutters tooth greater than 2 meters cutter hub.In actual use because manufacturing, adjustment or sharpening are improper, even the unequal or unequal situation of diameter of point of a knife height occurs, the cutter tooth of perhaps adjusting is when Milling Process, because back engagement of the cutting edge a _p, every group of amount of feeding a _FzChange slightly,, but still can realize free cutting, layer stripping and the effect that divides bits automatically though milling effect is not best.

Description of drawings

Fig. 1 is the profile of workpiece after the common stepped end milling.

Fig. 2 is the profile of workpiece after the free cutting hobbing for stepped end milling of the present invention.

Fig. 3 is the milling figure that two ladder free cutting hobbing for stepped end, the second rank cutter tooth tool cutting edge angle of the present invention equals 90 °.

Fig. 4 is two ladder free cutting hobbing for stepped end, the second rank cutter tooth tool cutting edge angle of the present invention less than 90 ° milling figure.

Fig. 5 is that two ladder free cutting hobbing for stepped end of the present invention equate the milling figure when unequal with respect to the diameter of end mill(ing) cutter axis at the relative machined surface height of point of a knife.

Fig. 6 is the operating position figure of two ladder free cutting hobbing for stepped end, the first rank cutter tooth cutting edge of the present invention.

Fig. 7 is the operating position figure of two ladder free cutting hobbing for stepped end, the second rank cutter tooth cutting edge of the present invention.

Fig. 8 is that two ladder free cutting hobbing for stepped end of the present invention are unequal at the relative machined surface height of point of a knife, the milling figure during with respect to the equal diameters of end mill(ing) cutter axis.

Fig. 9 is the milling figures of two ladder free cutting hobbing for stepped end N of the present invention when being even number.

Figure 10 is the milling figure of three ladder free cutting hobbing for stepped end of the present invention.

Figure 11 is the upward view of embodiments of the invention one.

Figure 12 is the installation diagram of knife bar on cutter hub.

Figure 13 is and the corresponding vertical view of Figure 11.

Figure 14 is and the corresponding partial right side view of Figure 12.

Figure 15 is the first rank cutter tooth of the embodiment of the invention one and the tool cutting edge angle and the relative height relation schematic diagram of the second rank cutter tooth.

Figure 16 is the upward view of the embodiment of the invention two.

Figure 17 is that the milling cutter radius and the tool cutting edge angle of the first rank cutter tooth, the second rank cutter tooth and the 3rd rank cutter tooth of the embodiment of the invention two concerns schematic diagram.

Figure 18 is the installation diagram of closed teeth end milling cutter cutter tooth.

Among the above-mentioned figure:

1, cutter hub 2, fabrication hole 3, installing hole 4, the first rank cutter tooth

5, the second rank cutter tooth 6, the first rank cutter tooth 7, the second rank cutter tooth 8, axial location ring

9, cylinder pin hole 10, straight pin 11, holding screw 12, spiral compression spring

13, wedge shape knife bar 14, carbide chip 15, blade installation slot 16, briquetting

17, trip bolt 18, trip bolt 19, side keyway 20, voussoir

21, studs 22, the first rank cutter tooth 23, the second rank cutter tooth 24, the 3rd rank cutter tooth

25, the first rank cutter tooth 26, the second rank cutter tooth 27, the 3rd rank cutter tooth

28, the processing plane 29 of workpiece, end mill(ing) cutter axis 30, interior hexagonal nose cone screw

31, nose cone 32, internal conical surface 33, wedge surface

a _pFor back engagement of the cutting edge N is a milling surplus isodisperse

R ₀₁, R ₀₂, R ₀₃The distance that is respectively the first rank cutter tooth, the second rank cutter tooth, cutter tooth point of a knife opposite end, the 3rd rank milling cutter axis is the milling cutter radius

a _fEach cutter tooth feed engagement a _FzThe amount of feeding of every group of cutter tooth

K _R1, K _R2, K _R3Be respectively the tool cutting edge angle of the first rank cutter tooth, the second rank cutter tooth, the 3rd rank cutter tooth

H ₁, H ₂, H ₃Be respectively the distance of the point width cutter hub baseplane of the first rank cutter tooth, the second rank cutter tooth, the 3rd rank cutter tooth

H _1-2Difference in height between the first rank cutter tooth and the second rank cutter tooth

The specific embodiment

Below in conjunction with embodiment and accompanying drawing thereof free cutting hobbing for stepped end of the present invention and method of adjustment thereof are described in detail, but free cutting hobbing for stepped end of the present invention and method of adjustment thereof are not limited to following embodiment.

The free cutting hobbing for stepped end that Figure 11, Figure 13 provide has 1, eight cutter tooth of discoidal cutter hub and is installed on the cutter hub 1 through the wedge shape knife bar.The knife bar bottom land of the big face push type broach body 1 of wedge shape knife bar 13, voussoir 20 is from tool post ramp chucking wedge shape knife bar 13, and the threaded one end that studs 21 screws in cutter hub 1 is dextrorotation, and the screw of the other end and voussoir 20 is left-handed.Voussoir 20 has just tightened wedge shape knife bar 13 when studs 21 screws in cutter hub 1, otherwise just unclamps knife bar 13.Axial location ring 8 usefulness trip bolts 18 are fastened on the cutter hub 1.There is blade installation slot 15 lower end of the wedge shape knife bar 13 of present embodiment, and carbide chip 14 is installed in the blade installation slot 15, and carbide chip 14 usefulness trip bolts 17 are pushed down by briquetting 16, referring to Figure 12, Figure 14.Present embodiment is two ladder free cutting hobbing for stepped end, and per two cutters tooth are one group, have four groups, is one group as the first rank cutter tooth 4 among Figure 11 and the second rank cutter tooth 5, and the first rank cutter tooth 6 and the second rank cutter tooth 7 are one group.The distance of each cutter tooth point width end mill(ing) cutter axis of present embodiment is equal, i.e. milling cutter diameter 2R ₀₁=2R ₀₂=200 millimeters, choose chipping allowance isodisperse N=3 respectively, back engagement of the cutting edge a _p=6 millimeters, the amount of feeding a of every group of cutter tooth _Fz=0.6 millimeter/group, the tool cutting edge angle K of the first rank cutter tooth 4 _R1=45 °, the height of point of a knife is unequal, and the point of a knife of the second rank cutter tooth 5 is lower than the point of a knife of the first rank cutter tooth 4, referring to Figure 15.The formula that the substitution present specification provides (1) can be tried to achieve the tool cutting edge angle K of the second rank cutter tooth 5 _R2=55 °.With fixed parameter and the tool cutting edge angle K that tries to achieve _R2=55 °, substitution formula (6) can be tried to achieve the point of a knife height difference H of the point of a knife and the first rank cutter tooth 4 of the second rank cutter tooth 5 _1-2=1.143, get approximation 1.14.The distance of bottom surface of getting the point width cutter hub 1 of the first rank cutter tooth 4 is 40.00 millimeters, and the distance of the bottom surface of the point width cutter hub 1 of the second rank cutter tooth 5 is 41.14 millimeters.

Free cutting hobbing for stepped end embodiment two of the present invention sees Figure 16, present embodiment is three ladder free cutting hobbing for stepped end, per three cutters tooth are one group, four groups have 12 cutters tooth, the point of a knife height of 12 cutters tooth equates, as the distance H of the point width cutter hub baseplane of the first rank cutter tooth, the second rank cutter tooth, the 3rd rank cutter tooth ₁=H ₂=H ₃=40 millimeters, promptly all in same plane.Cutter tooth is identical with embodiment one in the installation of cutter hub 1.For example first ladder 22, the second rank cutter tooth 23 and the 3rd rank cutter tooth 24 are one group among the figure, and the first rank cutter tooth 25, the second rank cutter tooth 26 and the 3rd rank cutter tooth 27 are another group.The milling cutter diameter of the point of a knife of three cutters tooth of every group is unequal, R ₀₁＜R ₀₂＜R ₀₃Referring to Figure 17, choose chipping allowance isodisperse N=6 respectively, back engagement of the cutting edge a _p=10 millimeters, the amount of feeding a of every group of cutter tooth _Fz=0.5 millimeter, the tool cutting edge angle K of the first rank cutter tooth 22 _R1=50 °.Above-mentioned parameter substitution formula (1`) is tried to achieve the tool cutting edge angle K of the second rank cutter tooth 23 <sub>R2</sub>=61.67 °, K <sub>R2</sub>Substitution formula (2`) is tried to achieve the tool cutting edge angle K of the 3rd rank cutter tooth 24 _R3=76.55 °.Get the milling cutter diameter 2R of the point of a knife of the first rank cutter tooth 22 ₀₁=1600 millimeters, then the milling cutter diameter of the point of a knife of the milling cutter diameter of the point of a knife of the second rank cutter tooth 23 and the 3rd rank cutter tooth 24 is respectively R ₀₃=1602 millimeters.

The cutter tooth of above-mentioned two embodiment is mounted on the knife bar, also can be welded on the carbide alloy cutter tooth on the knife bar.

Structure of the present invention for convenience of explanation, the foregoing description are example with two ladder free cutting hobbing for stepped end and three ladder free cutting hobbing for stepped end only.To the multi-ladder free cutting hobbing for stepped end more than two ladders, the tool cutting edge angle K of the initial configuration parameter first rank cutter tooth _R1, the first rank cutter tooth point of a knife milling cutter diameter 2R ₀₁, the first rank cutter tooth point of a knife height such as distance cutter hub bottom surface distance H ₁After determining, other structural parameters R ₀₂, R ₀₃, R ₀₄, K _R2, K _R3, K _R4, H ₂, H ₃, H ₄All the formula that can provide according to the present invention (1) to (12) is determined.

Closed teeth end milling cutter also can be worn into taper shape to hexagon socket cap head screw to socket cap with the circle voussoir of minor diameter, and hexagonal nose cone screw 30 in becoming replaces voussoir chucking knife bar.At cutter hub 1 and wedge shape knife bar 13 inner arc surface 32 and wedge surface 33 that matches with nose cone 31 arranged all.Hexagonal nose cone screw 30 in rotating, nose cone 31 is seen Figure 18 to wedge shape knife bar 13 chuckings.

The knife bar of this stepped end also can otherwise be installed on the cutter hub.

Claims (2)

1, a kind of free cutting hobbing for stepped end, it comprises cutter hub, knife bar, cutter tooth, install or welding a cutter tooth on each knife bar, knife bar is installed on the cutter hub, one to 12 group of milling cutter tooth is installed on the cutter hub, every group of two cutters tooth the rarest is characterized in that: last cutter tooth of every group of cutter tooth forms last rank, the tool cutting edge angle K of the first rank cutter tooth of every group of cutter tooth _R1All equate the tool cutting edge angle K of other same order cutter tooth _RmWith tool cutting edge angle K _R1All different, tool cutting edge angle K _RmAlong with the increase of m increases successively, the tool cutting edge angle K of the first rank cutter tooth wherein _R1Selected by the designer, K _RmBe the tool cutting edge angle of every group of cutter tooth m rank cutter tooth, m is that minimum is 2 natural number; The distance of the point width end mill(ing) cutter axis of all cutters tooth equates, the point of a knife of every group of cutter tooth first rank cutter tooth all with the same plane of end mill(ing) cutter axis normal in, the distance on this plane of point width of m cutter tooth of every group of cutter tooth is being left the direction of cutter hub, along with the increase of m increases successively; The tool cutting edge angle K of every group of each rank cutter tooth of cutter tooth _Rm, the point of a knife of m rank cutter tooth and m+1 rank cutter tooth point of a knife between range difference H _N-m, n=m+1 is determined by following formula respectively

${\mathrm{\&kappa;}}_{\mathrm{rm}}=\mathrm{arctg}\frac{a_p/N}{a_p/\mathrm{Nctg}{\mathrm{\&kappa;}}_{\mathrm{ru}}-a_{\mathrm{fz}}},m=\mathrm{2,3,4},\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;u=m-1$

For each m, k _RmAll get first

H _m-n＝H _n-H _m m＝1、2、3、4、……，n＝m+1

A in the above-mentioned general formula _pBe the back engagement of the cutting edge that the designer determines, the milling surplus isodisperse that the N designer determines, a _FzThe amount of feeding of every group of cutter tooth determining for the designer.

2, a kind of free cutting hobbing for stepped end, it comprises cutter hub, knife bar, cutter tooth, install or welding a cutter tooth on each knife bar, knife bar is installed on the cutter hub, one to 12 group of milling cutter tooth is installed on the cutter hub, every group of two cutters tooth the rarest is characterized in that: last cutter tooth of every group of cutter tooth forms last rank, the tool cutting edge angle K of the first rank cutter tooth of every group of cutter tooth _R1All equate the tool cutting edge angle K of other same order cutter tooth _RmWith tool cutting edge angle K _R1All different, tool cutting edge angle K _RmAlong with the increase of m increases successively, the tool cutting edge angle K of the first rank cutter tooth wherein _R1Selected by the designer, K _RmBe the tool cutting edge angle of every group of cutter tooth m rank cutter tooth, m is that minimum is 2 natural number; The point of a knife of each rank cutter tooth of every group of cutter tooth all with the same plane of end mill(ing) cutter axis normal in, the distance R of the point width end mill(ing) cutter axis of the first rank cutter tooth of every group of cutter tooth ₀₁All equate the distance R of the point width end mill(ing) cutter axis of the m rank cutter tooth of every group of cutter tooth _0mAlong with the increase of m increases the tool cutting edge angle K of every group of each rank cutter tooth of cutter tooth successively _Rm, m rank cutter tooth the distance R of point width end mill(ing) cutter axis _0mDetermine by following algebraic expression respectively

${\mathrm{\&kappa;}}_{\mathrm{rm}}=\mathrm{arctg}\frac{a_p/N}{a_p/\mathrm{Nctg}{\mathrm{\&kappa;}}_{\mathrm{ru}}-a_{\mathrm{fz}}},m=\mathrm{2,3,4},\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;u=m-1$

For each m, k _RmAll get first

R _0m＝R ₀₁+(m-1)a _fz

A in the above-mentioned general formula _pBe the back engagement of the cutting edge that the designer determines, the milling surplus isodisperse that N determines for the designer, a _FzThe amount of feeding of every group of cutter tooth determining for the designer.

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