CN1009174B - Gear cutting hob - Google Patents

Abstract

The present invention relates to a gear scraping hob. The present invention is characterized in that a convex curved involute surface is used as a hob tooth front hob surface, ruled spiral surfaces with specific guide-circle radii, which are matched with the hob tooth front hob surface are used as a hob tooth left hob surface, a hob tooth right hob surface and a hob tooth rear hob surface. The design accuracy of tooth shapes of the present invention can be ensured, and the closer of a point on the hob edge to the tooth top, the larger of the absolute value of the negative rake angle. When the present invention is used for the relief grinding of tooth shapes, straightness accuracy of any position on the rear hob surface can be measured, and therefore, the manufacture precision can be increased conveniently, and the precision retentivity is good. The present invention has the advantages of high wear resistance, high tipping resistance and large number of times of sharpening, and the total service life can be increased by 25 to 50%.

Description

Gear cutting hob

The invention belongs to the involute gear hob field.

The scraping used cutter of the flank of tooth that hardens is gear cutting hob.The hard flank of tooth technology of so-called scraping is used this class cutter exactly to through thick gear hobbing, and the smart gear hobbing before the flank of tooth that Overheating Treatment obtains higher hardness carries out final or finishing grinding tooth.

At present, domestic and international existing carbide skiving gear hob, its major technique feature is that rake face is the plane, and has the negative radial rake of big absolute value.Although this kind cutter cutter tooth has certain shock resistance, blade has certain anti-tipping blade ability,, because rake face is the plane, makes the shock resistance of its cutter tooth and anti-tipping blade ability be subjected to limitation, and the tipping phenomenon is arranged when existing, that is to say, if rake face is a convex surface then can be much better.But as cutter for gear wheel, in order to strictly observe the theory of engagement and the required precision of satisfying processed gear, the character of hobboing cutter rake face can not at will be determined again.

From the topographical method of existing carbide skiving gear hob, mainly contain two kinds of solutions at present.The first adopts the involute basic worm, the cutter tooth rake face is the plane, therefore, the left and right side edge of cutter tooth is two plane theory curves, knife face then is the plane theory curve as blade behind the left and right side of cutter tooth, a kind of bent bus helical that forms when for the helical movement by separately helical pitch, promptly the intersection of this helicoid and hobboing cutter axial section, worm screw method section and rake face all is not a straight line.This just makes when the relief grinding hob profile, can only be according to Principles of Gear Connection, utilize PWF250 type or PWF300 type hob checking equipment to measure hobboing cutter blade precision situation, it is not overproof to control it, but the precision situation at energy measurement hobboing cutter cutter tooth rear flank knife face other positions except that blade not, the precision situation after therefore hobboing cutter being refaced is felt unsure of, and often causes the hobboing cutter back precise decreasing of refacing, cause the number of times of refacing to reduce, the hobboing cutter terminal life shortens.And, need check the gearing line error △ T ∑ of hobboing cutter with PWF250 type that is worth the hundreds of thousands dollar or PWF300 type hob checking equipment in order to realize such measurement.It two is that the cutter tooth rake face also is the plane, but the left and right side edge of cutter tooth is not the plane theory curve, but replace the plane theory curve with the tangent line of plane theory curve at the cyclotomy place, this shows that knife face behind the left and right side of hobboing cutter cutter tooth is that the tangent line of these two replacements is the circle of leading of hobboing cutter rake face side-play amount E along radius, the straight grained helical that forms when for the helical movement by separately helical pitch, this moment, the design basic worm side surface of hobboing cutter also was a straight grained helical, and its helical pitch equals the helical pitch of same specification involute helicoid worm.Because its rear flank knife face of this kind topographical method is a straight grained helical, therefore when the relief grinding hob profile, comprise any position of blade on the knife face of energy measurement rear flank, there is number at the center of accomplishing.But, owing to having replaced the plane theory curve, tangent line brought hob profile design error (also claiming profile of tooth constant error or theoretical profile error), and bigger.Such as: when the MN=4 millimeter, the tooth Shape Design error E L at rake face upper left side sword tooth top place ₁=2.7 microns, the tooth Shape Design error E L at sword tooth root place, left side ₂=3.1 microns, considerably beyond being used to process corresponding 0.8 micron the profile of tooth constant error that hobboing cutter allowed of 8 class precision gears (JB179-83).And the side-play amount E of rake face only equals 5 millimeters at this moment, even get less outer diameter D _K=110 millimeters, its anterior angle also has only-5.2 °.Therefore, its shock resistance and anti-tipping blade ability are limited.And the hobboing cutter back tooth Shape Design error of refacing rises very soon, causes the number of times of refacing to descend, and hobboing cutter shortens entire life.

In a word, above-mentioned two kinds of topographical methods, all exist the number of times of refacing few and the time weakness of tipping arranged.

The object of the present invention is to provide a kind of wearability height, anti-tipping blade performance strong, reface often, use the gear cutting hob of high new formation method carbide alloy (or other cutter materials) entire life.

So-called new formation method propose exactly a kind of with involute surface as cutting hob cutter tooth rake face (1 '), with the straight grained helical that is complementary with it with specific guide radius of circle (23 " and 24 ") as cutting hob cutter tooth left and right side after the topographical method of knife face (3 ' and 4 ').By the gear cutting hob of this new formation method design, structurally its technical characterictic and usefulness are: 1) rake face of this cutting hob cutter tooth (1 ') is an involute surface, also is a kind of convex surface, so the impact resistance of cutter tooth is strengthened.Because involute has separability, after the rake face, the character of its rake face is constant so hobboing cutter is refaced, sharpening, the convenience of refacing, and precision stability is good; 2) knife face behind the left and right side of this cutting hob cutter tooth (3 ' and 4 ') is the straight grained helical with specific guide radius of circle (23 " and 24 ") that is complementary with rake face, the main prerequisite of coupling specific guide radius of circle (23 " and 24 ") is to guarantee that the cutter tooth designed toothform precision reaches the requirement of 7 grades of processing or 8 grades of gears (JB179-83), so designed toothform precision height, again owing to be straight grained helical, so it is convenient to measure during the relief grinding profile of tooth, can survey the linearity at any position of knife face, rear flank, and then increase the number of times of refacing; 3) these cutting hob cutter tooth two side edges (5 ' and 6 ') be rake face (1 ') and the straight grained helical that is complementary with it (3 ' and 4 ') with specific guide radius of circle intersect and must two space curves, be to cross tooth top relatively, two convex space curves on the plane of tooth root, so wearability is higher, on the blade every bit all be on the end face involute of involute surface rake face a bit, the pressure angle of this point is the negative rake of this point on the blade, therefore the point of past more tooth top direction on the blade, the absolute value of its negative rake is big more, overcome the absolute value minimum of existing cutting hob cutter tooth tooth top position negative rake, thereby all than weak situation, so the anti-performance that collapses of blade is better.4) the design basic worm of hobboing cutter is a kind of bent bus worm screw that blade forms when for the helical movement by its helical pitch (equaling the helical pitch of same specification involute helicoid worm), it is very close with theoretical involute helicoid worm, reaches the requirement of 7 grades of processing or 8 grades of gears (JB179-83) so can guarantee the cutter tooth designed toothform precision; 5) this cutting hob cutter tooth back, top (2 ') is that its end section cuts a kind of curved surface that shape is an Archimedes spiral, and is not only easily manufactured, and hobboing cutter refaces after the rake face, and its top relief angle remains unchanged substantially; 6) end of this cutting hob chip pocket (8 ') cuts shape, by back of tooth straight line (11 '), radius (the bottom land circular arc determined of 20 "), the end face involute (9 ') of rake face (1 '), and end face involute (9 ') and radius (one section RADIAL (10 ') composition between the bottom land circular arc determined of 20 ") from basic circle (18 ') beginning.RADIAL (10 ') claims Clearance angle with the angle of tooth back line (11 '), and (17 ") are 20 °～40 ° to its angle.Chip pocket (8 ') is a straight trough, easily makes accurately.

New formation method gear cutting hob, its design calculation theory derivation of equation is as follows:

(1) straight grained helical with specific guide radius of circle (23 " and 24 ") as the left and right side of hobboing cutter cutter tooth (2) after knife face (3 ' with 4 '), see Fig. 3 and Fig. 4, its equation is:

Wherein:

P _LKnife face helicoid helical pitch behind the-left side

P _RKnife face helicoid helical pitch behind the-right side

r _yThe projection of vector on end face of-discussion point B

r _WLKnife face leads radius of circle behind the-left side

r _WRKnife face leads radius of circle behind the-right side

The corner of θ-discussion point

α _LThe straight edge line of-left side helicoid and the angle of end face, the i.e. profile angle of back, left side knife face in leading round section

α _RThe straight edge line of-right side helicoid and the angle of end face, the i.e. profile angle of knife face behind the right side in leading round section

(2) can make left and right side edge (5 ' and 6 ') go up each point and have rake face (1 ') (see figure 5) of the involute surface of big negative rake as the hobboing cutter cutter tooth, its equation is:

Wherein:

θ _yThe infolute function of-discussion point B

θ _EyThe infolute function at-hobboing cutter cutter tooth tooth top place

α _yThe pressure angle of-discussion point, the negative rake value γ of the point on the promptly corresponding blade _B

α _EyThe pressure angle at-hobboing cutter cutter tooth tooth top place, i.e. the negative rake value γ at cutter tooth top sword place _K

r _e-hobboing cutter cutter tooth tooth top radius

r _cThe base radius of-involute surface rake face

r _yThe radius of-discussion point B

As seen by above-mentioned, involute surface rake face (1 ') is a kind of convex surface, and can make two side edges (5 ' and 6 ') obtain the very big negative rake of absolute value.

(3) simultaneous equations (a) and (b) just the equation of hobboing cutter cutter tooth left and right side blade (5 ' and 6 '):

Two side edges are space curve.

(4) the helicoid equation of hobboing cutter design basic worm:

Make cutting edge for the helical movement by the helix parameter (equaling the helix parameter of same specification involute helicoid worm) of hobboing cutter design basic worm, just obtain designing the side helicoid of basic worm, as the helical pitch that designs basic worm is P, certain a bit turns over the ω angle on the blade, and this X coordinate that then designs on the basic worm side surface is:

If: (θ+α _XL)+ω=θ ', i.e. θ+ω=θ '-α _XL

Then following formula becomes following formula:

α wherein _X, be α when being used for the left side _XL, be α when being used for the right side _XR

(5) the axial tooth profile equation of design basic worm:

Make (θ+ω)=(θ '+α _X)=0 is promptly:

This shows that the design basic worm is bent bus worm screw.

(6) design the slope of basic worm axial tooth profile at hobboing cutter cyclotomy place:

To the differentiate of (e) formula promptly:

Wherein:

r _o-hobboing cutter divides radius of circle

Because the involute surface rake face also belongs to the straight trough hobboing cutter, therefore there is following relationship:

Wherein:

K _t-back-off amount in leading circle (12 ' or 14 ') section

Z _k-hobboing cutter chip pocket number

The back-off amount K of hobboing cutter in leading circle (12 ' or 14 ') section _tThere is following relationship, (see figure 6) with the back-off amount K in the radial section.

With (g) formula substitution (f) Shi Kede:

(7) have the left-handed of specific guide radius of circle or dextrorotation straight grained helical, its bus and end face angle, promptly lead circle (12 ' or 14 ') tangent plane flat in the profile angle of hobboing cutter rear flank knife face, by following principle and formula calculating:

Make (i) formula equal the slope of involute helicoid worm at the cyclotomy place, its concrete numerical value is:

tgα _xi＝±tgα _n/cosλ。

"+" number is used for the left side; "-" number is used for the right side.

That is:

This formula can further be write as following form:

Wherein:

α _n-involute helicoid worm normal direction circle-dividing pressure angle

λ _o-involute helicoid worm also is the cyclotomy lead angle of design basic worm

By angle [alpha] _LAnd α _R, the linearity of knife face behind the measurement left and right side in leading circle (12 ' and 14 ') section.

(8) calculating of theoretical profile error (also claiming tooth Shape Design error or profile of tooth constant error):

1. design basic worm axial tooth profile equation (e) can be write as following form again:

Wherein:

P/2π＝MN/2·cosλ。

The normal module of MN-hobboing cutter

2. dextrorotation involute helicoid worm left and right side surface axle cuts the shape equation:

X _i＝± (P)/(2π) ·invα _t

"+" is used for left surface; "-" is used for right flank.

α _t＝cos ^-1（r _b/r _y）

Wherein:

α _t-involute helicoid worm end cuts shape any point pressure angle

r _b-base circle of involute helicoid worm radius

P-involute helicoid worm helical pitch also is a design basic worm helical pitch.

∵P＝πMN/cosλ。

The ∴ following formula can be write as following form:

3. calculating involute helicoid worm axle cuts shape and designs the basic worm axle and cut the difference Q of shape at the X of minute round dot coordinate figure _i

4. design basic worm axle cuts the axial theoretical profile error of shape each point (equating with error in the base circle of involute helicoid worm section):

5. design the theoretical profile error of basic worm in the path of contact direction:

Wherein:

λ _L-base circle of involute helicoid worm lead angle

(9) about the calculating of regrinding error:

Radially always the amount of refacing △ r is greatly in the scope of (0.15～0.2) MN for carbide hob, and for whole high-speed steel hobboing cutter, its △ r is greatly in the scope of (0.4～0.6) MN.The radius of tooth top after refacing and tooth root available point (23 ' and 25 ') is a (see figure 7):

r _f＝r _e+（c ₁-1.2）MN-△r （P）

c ₁=1 o'clock is the available point after tooth top is refaced

c ₁=-1 o'clock is the available point after tooth root is refaced

For making the gear cutting hob tooth top not participate in cutting, addendum coefficient gets 1.2, and the height of teeth root coefficient still gets 1.25.

(10) tooth proportions:

Make and measure convenient for making, on the hobboing cutter work sheet, provide and lead circle (12 ' and 14 ') section internal tooth form figure, hobboing cutter tooth profile of rake face figure and hobboing cutter tooth form of axial direction figure.

1. lead round section profile of tooth figure:

Since behind the cutter tooth left and right side knife face lead the radius of circle difference, so on the left of and the round section of leading on right side do not overlap.Leading in circle (12 ') section of back, left side knife face, the left side is a straight line, the right side is the curve (see figure 8); Leading of knife face justified in (14 ') section behind the right side, and the right side is a straight line, and the left side is the curve (see figure 9).Straight line is the bus (13 ' or 15 ') of straight grained helical, and the angle of they and end face is promptly led internal tooth form angle, round section.Left side (25 ")=α _L; Right side (26 ")=α _R; Measure when this angle supplies the relief grinding profile of tooth and use.Promptly measure the linearity of straight edge line (13 ' or 15 '), (seeing Fig. 3 and Fig. 4).

2. tooth profile of rake face figure:

Rake face is not the plane, but involute surface, two side edges are space curve, but can see approx that it is the plane, (see figure 10).On this figure, mainly mark axial pitch (28 ")=P, axial tooth thickness (27 ")=S, rake face height of teeth top (31 ")=h _t(the air line distance EB at the cyclotomy place that is tooth top to the rake face sees Figure 11) and rake face whole depth (32 ")=h _t(the air line distance EI at the root circle place that is tooth top to the rake face sees Figure 11) measured during in order to teeth and roll flute and used.Can calculate height of teeth top EB and whole depth EI according to Figure 11.

Known:

Hobboing cutter tip circle radius r _e

Hobboing cutter cyclotomy radius r _o

Hobboing cutter root radius r _I

The pressure angle α of tooth top place on the rake face _Ey

The pressure angle α of tooth root place on the rake face _Iy

The pressure angle α of cyclotomy place on the rake face _Ey

Calculate:

θ _ey＝tg（α _ey）-α _ey

θ _I＝tg（α _IY）-α _IY

θ _o＝tg（α _ey）-α _ey

＜BOC＝θ _ey-θ _o

＜IOJ＝θ _ey-θ _I

BC＝r _o·sin（＜BOC）

IJ＝r _I·sin（＜IOJ）

$\mathrm{CO\; =}\sqrt{r{}^2{}_O\mathrm{-\; BC}{}^2}\mathrm{JO\; =}\sqrt{r{}^2{}_i\mathrm{-\; IJ}{}^2}$

EC＝r _e-CO

EJ＝r _e-JO

${\mathrm{\therefore \; h\; ＇}}_t\mathrm{=\; EB\; =}\sqrt{\mathrm{EC}{}^2\mathrm{+\; BC}{}^2}{h}_t\mathrm{=\; EI\; =}\sqrt{\mathrm{EJ}{}^2\mathrm{+\; IJ}{}^2}$

The transverse tooth thickness at cyclotomy place: S=P/2 on the rake face

Radius at tooth tip on the rake face: r _a=0.2MN

Tooth fillet radius on the rake face: r _i=0.2MN

3. tooth form of axial direction figure

The axle of hobboing cutter cutter tooth rear flank knife face cuts shape such as Figure 12, and both sides are curve.The profile angle of (carbide skiving gear hob is not weld blade cutter hub teeth before) perching knife is got the profile angle (33 " and 34 ") that hobboing cutter cutter tooth rear flank knife face axle cuts shape cyclotomy place, (33 ")=α during teeth _OL, (34 ")=α _OR

The derivation of equation of calculating this two angle is as follows:

Make θ=0 in (a) formula, get the axial truncatus equation of rear flank knife face:

To the differentiate of (q) formula, and make y=r _o, then try to achieve rear flank knife face axle and cut the slope of shape at the cyclotomy place:

Axial tooth profile height of teeth top (35 ")=h ^' _x=r _e-r _o; Whole depth (36 ")=h _x=r _e-r _I

(11) chip pocket size:

The end of chip pocket (8 ') cuts shape and is made up of for the one section RADIAL (10 ') that is begun by basic circle (18 ') between the bottom land circular arc of (20 ") the end face involute (9 ') of bottom land circular arc for (20 ") of back of tooth straight line (11 '), radius, rake face and end face involute (9 ') and radius.Angle (17 ') between RADIAL (10 ') and back of tooth straight line (11 ') claims Clearance angle δ, and its angle is 20 °～40 °, (seeing Figure 13 and Fig. 2).

As cutting tip welding carbide chip, the angle between insert groove side (27 ') and the RADIAL (10 ') (37 ")=ω, its computing formula is as follows:

ω＝（90°-γ）-（tgγ-γ） （t）

Wherein γ is the absolute value of cyclotomy place negative rake.

The insert groove lateral width is that (38 ")=b determine according to the hobboing cutter length of refacing.

Capacity chip slot depth be (22 ")=H, the H computing formula is:

H＝r _e-r _x+k+（2～5） （u）

Arc radius at the bottom of the chip pocket (20 ")=r, r is calculated as follows:

$\mathrm{r\; =}\frac{{\mathrm{\pi \; (D}}_{\Sigma }\mathrm{-\; 2H\; )}}{{\mathrm{10Z}}_K}\mathrm{(V)}$

Wherein: Z _kBe hobboing cutter groove number; K is back-off amount radially; D _xBe the hobboing cutter external diameter; r ₁Be hobboing cutter root footpath.Radially the back-off amount (15 ")=K, K is calculated as follows:

K＝πD _K/Z _k·tgα _K（w）

α wherein _KBe tooth top relief angle, α _KGenerally get 10 °～12 °.

(12) cutter hub and blade size:

Cutting tip as gear cutting hob adopts carbide alloy, and connect with cutter hub with silver soldering, the external diameter of cutter hub before milling cutter film trap not is than the little 2 △ R of cutting hob external diameter, general △ R is in (0.5～2) millimeter scope, do not cause when guaranteeing relief grinding carbide chip top back knife face and rear flank knife face emery wheel to run into knife face and rear flank knife face behind the top of insert supporting part (7 '), just make the back knife face phase blade relief grinding of cutter tooth supporting part (7 ') after knife face individual decrease (19 ") are arranged.The cutter hub endoporus is before heat treatment, and that leave (0.5～1) millimeter stays the mill amount.

Carbide chip can adopt monodentate form (as Figure 14 and Figure 15), also can adopt the tooth bar form, and promptly quite several monodentate blades are stitched together and become a tooth bar.Monodentate carbide chip, bottom surface are the plane, and end face is a circular arc in the end section, and (45 ")=R, R are the substituted circular of end face involute (9 ') to its radius.Blade width (39 ")=B, during the single head hobboing cutter, B=P.Blade thickness (43 ')=C is than insert groove lateral width (38 ") big (0.5～2) millimeter.Blade side bias (42 ") is α ' and α ", α '=α " ≈ (α _L+ α _R)/2, blade lengths (44 ")=ι, calculate by following approximate formula:

ι＝（r _e-r _c）/cosγ （x）

Blade shoulder width (42 ") equal g, and g calculates by following approximate formula:

$\mathrm{g\; =}\frac{P}{2}\mathrm{-\; ｛}\frac{S}{2}\mathrm{+\; (0.5\; ～\; 2\; )\; +\; ［}\frac{r_o{\mathrm{-\; r}}_1}{\mathrm{cos\; \gamma }}\mathrm{-\; (0.5\; ～\; 2\; )\; ］\; ·\; tga\; ＇\; ｝\; (y)}$

Blade shoulder starting point length (40 ") equal J, and J calculates by following approximate formula:

$\mathrm{J\; =\; l\; -\; ［}\frac{r_o{\mathrm{-\; r}}_1}{\mathrm{cos\; \gamma }}\mathrm{-\; (0.5\; ～\; 2\; )\; ］\; (z)}$

Aspect manufacturing process, the special character following points of new formation method gear cutting hob: the 1. grinding of involute surface rake face (1 '), need on gear grinding machines, to be undertaken, when being carbide alloy, also need use skive as hobboing cutter cutter tooth cutting tip by generating; When refacing rake face, also on gear grinding machines, press generating processing.The involute profile precision, the tooth pitch precision of rake face, the depth of parallelism of rake face and hobboing cutter axis all need reach the regulation of technical conditions.2. the relief grinding of knife face behind the hobboing cutter cutter tooth left and right side (3 ' and 4 ') needs carry out on the high accuracy machine for relief grinding, as the cutter tooth cutting tip is carbide alloy, also need use skive, in the section of leading circle (12 ' and 14 '), press the position of Fig. 3 and Fig. 4, measure the linearity of knife face behind the cutter tooth left and right side according to leading radius of circle (23 " and 24 ") and internal tooth form angle, section (25 " and 26 "), measure the helix error of cutter tooth simultaneously, make it all reach regulation in the technical conditions.3. be carbide alloy as the cutter tooth cutting tip, the manufacturing procedure of chip pocket on the cutter hub (8 ') should be earlier to equal single angle milling cutter that Clearance angle δ, radius of corner equal radius r at the bottom of the chip pocket with angle, mill out Clearance angle (17 ") according to capacity chip slot depth (22 "), then in Clearance angle RADIAL (10 ') side, from basic circle (18 '), according to the angle of insert groove lateral width (38 ") and side and RADIAL (10 ') (37 "), mill out the insert groove that is parallel to the hobboing cutter axis with slotting cutter.4. when the cutter tooth cutting tip is carbide alloy, before milling cutter film trap not, cutter tooth is carried out radially teeth processing according to knife face axial profile angle (33 " and 34 ") behind the radially back-off amount (15 ') of hobboing cutter and the left and right side.

The present invention has following advantage:

1. can be (as MN=4 under the prerequisite of guaranteeing very high designed toothform precision, △ f≤0.8 micron), can be at the linearity of leading test hobboing cutter cutter tooth rear flank knife face within the round section, thereby can be controlled at the precision after refacing within the scope of requirement, reaching increases the number of times of refacing, the purpose that prolongs entire life.Because carbide alloy gear cutting hob price comparatively expensive (when MN=4, being a handle about 2,000 yuan) therefore, increases the entire life of hobboing cutter, its economic benefit is very considerable.And the plane rake face carbide skiving gear hob that adopts at present or can't be tested other positions (when adopting the involute basic worm) outside the blade, and the therefore precision after uncontrollable the refacing is so the number of times of refacing is few; The design accuracy of itself is very low, the back error of refacing increases rapidly, just can not be used for processing 8 class precision gears (JB179-83) so that do not add reconditioning off normal value at all, and the absolute value of negative rake often be subjected to the restriction of error amount and can not obtain big, so superiority of negative rake can not give full play to the hard flank of tooth of scraping the time.

2. when enforcement is of the present invention, in relief grinding profile of tooth process, can test by expensive PWF250 type hob checking equipment, and can be at the linearity of leading build-in test rear flank, round section knife face with simple contact type measurement means.Sundry item in the specification requirement is without any special character, so big tools factory all can make.PWF250 type hob checking equipment that need not be expensive can make the hobboing cutter manufacturing cost descend.

3. the present invention is a kind of convex surface because the cutter tooth rake face is an involute surface, has increased the impact resistance and the wearability of cutter tooth.Simultaneously, cutter tooth not only has the feature of big negative rake, and is from the cutter tooth root, and the absolute value of the radially negative rake of side edge each point increases gradually.During as the MN=4 millimeter, the cyclotomy anterior angle is-30 °, and the tooth root place is about-20 °, and the tooth top place is about-36 °.The weak link tooth top of cutter tooth has partly obtained the negative rake of bigger absolute value.It can make the impact resistance and the anti-tipping blade performance of the tooth top part that is prone to tipping be improved, and can increase its wearability.Replace the plane with convex surface, will reduce the tipping phenomenon of carbide alloy gear cutting hob.

4. involute surface rake face of the present invention can be on high-precision Magg type gear grinding machines sharpening and refacing.Therefore can make rake face obtain higher positional precision and fineness.This will help the further raising of the whole hobboing cutter accuracy of manufacture, and precision stability is good.

5. because the wearability of cutter tooth is better, and the anti-tipping blade performance is stronger, and the number of times of refacing is more, therefore can make hobboing cutter raising entire life (25～50) %.

Description of drawings:

Fig. 1 is the front view of gear cutting hob.Wherein:

1 is cutter hub; 2 is blade, i.e. cutter tooth; 1 ' be the rake face of cutter tooth; 5 ' and 6 ' be respectively the left and right side edge of cutter tooth; 1 " is outer diameter D _E; 2 " be circle-dividing diameter d _o; 3 " be pillow block diameter D ₁; 4 " be inner hole grinding undercut diameter d ₁; 5 " be length L; 6 " be pillow block width L ₁; 7 " be pillow block end face chamfering C ₁* 45 °; 8 " be cyclotomy lead angle λ _o; 9 " be the inner hole grinding width B ₁; 10 " be interior hole end surface chamfering C ₂* 45 °; 11 " be inner hole grinding undercut radius of corner R ₁; 12 " be pillow block radius of corner R ₂

Fig. 2 is the left view of gear cutting hob.Wherein:

2 ' be knife face behind the cutter tooth top; 3 ' and 4 ' be respectively knife face behind the cutter tooth left and right side; 7 ' be the cutter tooth supporting part; 8 ' be chip pocket; 9 ' be the end face involute of involute surface rake face; 10 ' be one section RADIAL; 11 ' be back of tooth straight line; 13 " be diameter of bore d; 14 " be the base circle diameter (BCD) d of involute surface rake face _c; 15 " be back-off amount K radially; 16 " be cyclotomy radial rake γ _o; 17 " be Clearance angle δ; 18 " be inner hole key slot width b ₁; 19 " be the decrease △ R of knife face phase blade relief grinding part behind the cutter tooth supporting part; 20 " be radius r at the bottom of the chip pocket; 21 " be the inner hole key slot height t ^' ₁; 22 " be capacity chip slot depth H.

Fig. 3 is that back, cutting hob cutter tooth left side knife face forms schematic diagram.Wherein:

12 ' be the circle of leading of back, cutter tooth left side knife face; 13 ' for generating the straight edge line of back, left side knife face; 23 " lead radius of circle r for knife face behind the left side _HL

Fig. 4 is that knife face forms schematic diagram behind the cutting hob cutter tooth right side.Wherein:

14 ' be the circle of leading of knife face behind the cutter tooth right side; 15 ' be the straight edge line of knife face behind the generation cutter tooth right side; 24 " lead radius of circle r for knife face behind the right side _HR

Fig. 5 is that the involute surface rake face of cutting hob cutter tooth forms schematic diagram.Wherein:

16 ' be the normal of any point on the rake face end face involute; 17 ' be the tangent line of any point on the rake face end face involute; 18 ' be the basic circle of rake face end face involute; 19 ' be the cyclotomy of cutting hob; 20 ' be the pitch circle of any point on the rake face end face involute; 21 ' be the cutting hob cylindrical.

Fig. 6 is radially back-off amount K and tangential back-off amount K of cutting hob _tGraph of a relation.

Fig. 7 is that design basic worm axle cuts shape figure.Wherein:

22 ' and 29 ' be place, new cutter tooth top available point; 23 ' and 30 ' for always grinding off tooth top place available point behind the amount of the refacing △ r; 24 ' and 31 ' be new cutter tooth root place available point; 25 ' and 32 ' for always grinding off tooth root place available point behind the amount of the refacing △ r.

Fig. 8 is the profile of tooth figure of left side back knife face in leading round section.Wherein:

25 " be the left side profile angle α of knife face in leading round section behind the left side _L

Fig. 9 is the profile of tooth figure of knife face in leading round section behind the right side.Wherein:

26 " be the right side profile angle α of knife face in leading round section behind the right side _R

Figure 10 is the approximate profile of tooth figure of involute surface rake face.Wherein:

27 " be axial tooth thickness S; 28 " be axial pitch, be hobboing cutter helical pitch P during single head; 29 " be radius at tooth tip r _a; 30 " be tooth fillet radius r _i; 31 " be height of teeth top h ^' _t; 32 " be whole depth h _t

Figure 11 is the geometrical relationship figure that calculates involute surface rake face height of teeth top and whole depth.Wherein:

26 ' be the root circle of cutting hob, its diameter is D _I

Figure 12 is rear flank knife face axial tooth profile figure.Wherein:

33 " be knife face axial profile angle α behind the left side _OL; 34 " be knife face axial profile angle α behind the right side _OR; 35 " be height of teeth top h ^' _X; 36 " be whole depth h _X

Figure 13 is the chip pocket dimensional drawing.Wherein:

27 ' be the insert groove side; 28 ' be the insert groove bottom surface; 37 " be the angle ω of insert groove side and RADIAL; 38 " be insert groove lateral width b.

Figure 14 is the blade front view.Wherein:

39 " be blade width B; 40 " be shoulder starting point length J; 41 " being side oblique angle α '=α "; 42 " be shoulder width g.

Figure 15 is the blade side view.Wherein:

43 " be blade thickness C; 44 " be blade lengths ι; 45 " be blade end section end face arc radius R.

Embodiment:

By above-mentioned new formation method and its theoretical calculation formula, to the cutting hob of any modulus, but by Computing all one group of optimization guarantee the design parameter and the physical dimension of theoretical profile error very small (the profile of tooth constant error that allows as the AA level cutting hob of MN=4 should≤0.8 micron).Be how example illustrates designing and calculating AA level new formation method carbide alloy gear cutting hob with the flank of tooth that hardens of scraping processing MN=4 below.

1. physical dimension and design parameter:

The MN=4 millimeter; D _E=140 millimeters; The d=50 millimeter;

The L=100 millimeter; Number Z _o=1; d _o=130.4 millimeters;

λ _o=1 ° 45 ' 28 "; The P=12.572 millimeter; γ _o=-30 °;

D _I=120.4 millimeters; The K=6 millimeter; Groove is counted Z _k=14;

r _HL=33.6 millimeters; r _HR=41 millimeters; d _C=112.9297 millimeters;

D ₁=90 millimeters; d ₁=52 millimeters; L ₁=10 millimeters;

C ₁* 45 °=1.5 * 45 °; C ₂* 45 °=1 * 45 °; B ₁=30 millimeters;

R ₁=1 millimeter; R ₂=1.5 millimeters; b ₁=12.12 millimeters;

t ^' ₁=53.5 millimeters; Rake face circle-dividing pressure angle α _Oy=30 °.

2. tooth proportions:

(1) leads round section internal tooth form, see Fig. 8 and Fig. 9.

α _L＝16°33′35″;α _R＝17°18′55″

(2) tooth profile of rake face, see Figure 10 and Figure 11:

The P=12.572 millimeter; The S=6.286 millimeter; r _a=0.8 millimeter;

r _i=0.8 millimeter; h ^' _t=5.74 millimeters; h _t=11.24 millimeters;

(3) tooth form of axial direction, see Figure 12:

α _OL＝18°25′16″;α _OR＝18°18′52″;

h ^' _X=4.8 millimeters; h _X=9.8 millimeters;

(4) chip pocket and insert groove size, see Figure 13:

δ=30 °; The H=19 millimeter; The r=2.5 millimeter;

ω=56.9 °; The b=4 millimeter;

(5) cutter hub and blade size, see Figure 14 and Figure 15:

The monodentate carbide chip is welded on the cutter hub of steel alloy with silver soldering technology.Blade material is 758, and the cutter hub material is 9SiCr.

Do not operate on the cutter hub external diameter decrease 2 △ R=2 millimeters of film trap;

Do not operate on the cutter hub outer diameter D of film trap ^' _K=140-2=138 millimeter;

Blade size is as follows:

The B=12.5 millimeter; The J=5.5 millimeter; "=17 ° of α '=α;

The g=1 millimeter; The c=5 millimeter; ι=16 millimeter;

The R=28 millimeter.

(6) technical conditions:

This example is an AA level hobboing cutter, will check the following in the manufacture process:

(1) the helix error △ t=5 micron of adjacent cutting sword

(2) the helix error △ t of cutting edge in hobboing cutter one changes ₁=8 microns

(3) the helix error △ t of cutting edge in hobboing cutter three changes ₃=13 microns

(4) lead round section internal tooth form error △ f=6 micron

(5) rake face involute profile error △ f=6 micron

(6) the nonparallelism △ P=40 micron of rake face and interior axially bored line

(7) the adjacent difference of circular pitch △ tg=25 micron of chip pocket

(8) the cumulative maximum error △ Tg=40 micron of chip pocket circular pitch

(9) the circular runout △ a=6 micron of pillow block

(10) end face run-out △ b=4 micron

(11) endoporus deviation △ d=13 micron

(12) transverse tooth thickness deviation △ S=± 20 microns

Behind endoporus, rake face, the tooth top behind knife face, the flank roughness of knife face be , the pillow block cylindrical, the end face roughness is

, other non-roughness that grind the surface are

The hobboing cutter outer diameter D _EDeviation be ± 0.8 millimeter.

The deviation of hobboing cutter length L is ± 0.8 millimeter.

Claims (5)

1, a kind of gear cutting hob of forming by cutter hub (1) and blade (2), it is characterized in that: cutter tooth rake face (1 ') is a kind of involute surface of protruding song; Knife face behind the cutter tooth left and right side (3 ' and 4 ') be the straight grained helical that is complementary with rake face (1 ') with specific guide radius of circle (23 " and 24 "); The left and right side edge of cutter tooth (5 ' and 6 ') be a rake face (1 ') and two rear flank knife faces (3 ' and 4 ') intersect two space curves that get, be relatively two convex curves on tooth top, tooth root plane; Hobboing cutter design basic worm be a kind of by blade by the worm screw helical pitch bent bus worm screw that forms for the helical movement; The end of chip pocket (8 ') cuts shape to be made up of the end face involute (9 ') of back of tooth straight line (11 '), bottom land circular arc, rake face (1 ') and one section RADIAL (10 ') from basic circle (18 ') beginning between end face involute (9 ') and the bottom land circular arc, and back of tooth straight line (11 ') and RADIAL (10 ') constitute Clearance angle (17 ').

2,, it is characterized in that the described straight grained helical that is complementary with rake face (1 '), the angle (α of its bus (13 ' and 15 ') and end face with specific guide radius of circle (23 " and 24 ") by the described gear cutting hob of claim 1 _LAnd α _R) calculate by following theoretical formula respectively:

3, by the described gear cutting hob of claim 1, it is characterized in that described rake face (1 ') and two rear flank knife faces (3 ' and 4 ') intersect and two space curves, its theoretical equation is:

4, by the described gear cutting hob of claim 1, it is characterized in that described hobboing cutter design basic worm be a kind of by blade by the worm screw helical pitch bent bus worm screw that forms for the helical movement, the theoretical equation on this worm screw left and right side surface is:

θ ' wherein, θ '=(θ+α when being used for the left side _XL)+ω, θ ' when being used for the right side=(θ+α _XR)+ω

P is the helical pitch of design basic worm

ω is the corner of any point on the blade

y＝r _W·cos（θ+ω）＝r _W·cos（θ′-α _X）

z＝r _W·sin（θ+ω）＝r _W·sin（θ′-α _X）

α wherein _XWhen being used for the left side is α _XL, be α when being used for the right side _XR

5, by the described gear cutting hob of claim 1, it is characterized in that described Clearance angle (17 ') is 20 °～40 °.

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