CN102338091B - Enveloping tooth profile surface for meshing pair of single-screw compressor - Google Patents

Abstract

The invention relates to an enveloping tooth profile surface for a meshing pair of a single-screw compressor. The enveloping tooth profile surface comprises a star wheel tooth surface and a corresponding screw tooth groove profile surface; the whole star wheel tooth lateral surface can be engaged with the screw tooth groove surface; a meshing area of the star wheel tooth surface is a continuous meshing curve surface; and during meshing, a contact line of the star wheel tooth lateral surface and the screw tooth groove surface moves in the whole meshing curve surface. By a meshing pair tooth surface, a stable oil-film force can be applied to a star wheel, the service life of the single-screw compressor is prolonged, and the efficiency of the single-screw compressor is improved; by reasonably designing profiles surfaces of a tooth front side and a tooth rear side, oil-film bearing force can be uniformly distributed on the tooth front side and the tooth rear side of the star wheel, and the gaps between the tooth front side of the star wheel and a tooth groove and between the tooth rear side of the star wheel and the tooth groove during operation are equal.

Description

A kind of envelope Profile of AT structure of single helical-lobe compressor intermeshing pair

Technical field

The present invention relates to the structure of component of machine, particularly relate to a kind of Profile of AT structure of single helical-lobe compressor intermeshing pair.

Background technique

Compressor is widely used in the industries such as railway, steamer, mine, building, chemical industry, weaving, metallurgical machinery, military project instrument, naval vessels.Single screw compressor is compared with the cold compressor of reciprocating work, double-screw compressor, has the advantages such as simple in structure, running is reliable, volume is little, lightweight, noise is low.

State's external enwergy Manufacture Order screw air compressor have method, day, English, U.S., a Dutch Deng Shiyu company, some producers of China also start Manufacture Order helical-lobe compressor in recent years, but its performance index are general not as good as imported product.Particularly in the situation that using same material, and the Japanese star-wheel life-span is 2 times of left and right of China.At present, generally believe that this is the difference that the machining accuracy by single helical-lobe compressor intermeshing pair causes.According to the incomplete statistics of Chinese compressor association, approximately 3000～4000 of domestic whole single screw rod product in 2005 Annual output, and the annual turnover of double-screw compressor (main frame of offshore company accounts for more than 70%) has reached 80000～100000 more than.The Taiwan Fu Sheng company in Shanghai is an international style Compressor Manufacturing company, the main frame of always buying single screw compressor with high price from Mitsui company is now equipped with its auxiliary system, supplies domestic and international market.Therefore, single screw compressor has huge development space at home.But star-wheel odontotripsis is fast, working life, short problem became domestic two to be difficult to all the time during the last ten years the obstacle of going beyond.

The core component of single screw compressor is the engagement pair (Fig. 1) consisting of screw rod, star-wheel, and its processing is the place of difficulty maximum in the processing of single screw compressor part.And the molded line of engagement pair is very large on processing method and difficulty of processing impact.External published single screw compressor molded line has two kinds of lines enveloping and cylindrical envelopes.It is domestic that once someone proposed the molded line of twice-enveloping type, but all because processing problems not yet realizes.

Summary of the invention

Problem to be solved by this invention is to provide a kind of star-wheel flank of tooth of continuous engagement and corresponding teeth groove profile, can realize whole star-wheel flank and can mesh with screw rod alveolar surface, and the mesh regional of the star-wheel flank of tooth is a continuous integral body.

For reaching above object, the present invention takes following technological scheme to be achieved:

A kind of envelope Profile of AT structure of single helical-lobe compressor intermeshing pair, comprise the side of star-wheel tooth and the side of screw rod teeth groove, its screw rod teeth groove side is the envelope surface of star-wheel flank, it is characterized in that: star-wheel flank is comprised of continuous surface of action and two kinds of curved surfaces of discontinuous surface of action; Wherein, surface of action is the mesh regional of star-wheel flank and screw rod teeth groove side continuously, and its continuous surface of action is expanded to whole star-wheel flank most of, and discontinuous surface of action only occupies the fraction of whole star-wheel flank; Wherein, continuously surface of action at least one, the surface except continuous surface of action is discontinuous surface of action; In star-wheel tooth root position, surface of action reduced width is zero continuously; In engagement process, the Line of contact of star-wheel flank and screw rod teeth groove side moves in all continuous surface of actions; Wherein, the all plane γs vertical with star-wheel tooth and the continuous surface of action of star-wheel flank intersect formation intersection, the feature of the tangent line of this intersection in the vertical plane of described star-wheel tooth is: from this intersection near the end points of star-wheel upper surface to the end points near star-wheel lower surface, tangent line is monotonously change with the angle that is parallel to the horizontal plane λ on the upper and lower surface of star-wheel; This friendship curvature of a curve gradually changes.

In such scheme, described from this intersection near the end points of star-wheel upper surface to the end points near star-wheel lower surface, tangent line with the span of angle of horizontal plane λ that is parallel to the upper and lower surface of star-wheel by the definite scope [α of following formula _min, α _max] within:

$\mathrm{\&alpha;}=a\tan \left(\frac{\mathrm{Pa}-{\mathrm{<figure-callout\; id="2"\; label="Py"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Py</figure-callout>}}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}-{\mathrm{<figure-callout\; id="2"\; label="Px"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Px</figure-callout>}}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}{y_2-{\mathrm{<figure-callout\; id="2"\; label="Pz"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Pz</figure-callout>}}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}\right)$

In formula: φ _swfor the angle range of star-wheel tooth, the ratio of the groove number of the number of teeth that P is star-wheel and screw rod, a is the centre distance of star-wheel and screw rod, x ₂, y ₂, z ₂coordinate for certain point on intersection; φ _swangle range be that point on intersection can the span of the star-wheel tooth corner of engagement occur with screw rod teeth groove side, within the scope of this, according to above formula, seek out the scope [α at α angle _min, α _max].

Described intersection is divided into two kinds, and a kind of is continuous surface of action and intersection L perpendicular to star-wheel tooth plane γ _γ, another is discontinuous surface of action and intersection L perpendicular to star-wheel tooth plane γ _f, two kinds of intersection sections interconnect at the intersection of continuous surface of action and discontinuous surface of action, be connected and form a whole piece intersection of star-wheel flank before and after all intersection sections; At the plane γ vertical with star-wheel tooth, cross the tangent line that same tie point is made respectively aforementioned two-part intersection, and by L _ftangent line and the angle of horizontal plane X2-O2-Y2 be denoted as α _jf, by L _γtangent line and the angle of horizontal plane X2-O2-Y2 be denoted as α _{j γ}, the postive direction of definition Z2 axle is top, the negative direction of Z2 axle is below, for tooth rear side, if L _γat L _fbelow, at their intersection point place, α _jf≤ α _{j γ}; If L _γat L _ftop, at their intersection point place, α _{j γ}≤ α _jf; For tooth front side, if L _γat L _fthe below of intersection, at their intersection point place, α _{j γ}≤ α _jf; If L _γat L _ftop, at their intersection point place, α _jf≤ α _{j γ}.

Described horizontal plane λ and the star-wheel flank that is parallel to the upper and lower surface of star-wheel intersects another intersection of formation, and this intersection is divided into two-part, and a part is the intersection L of plane λ and continuous surface of action _λ, another part is the intersection L of plane λ and discontinuous surface of action _g, in plane λ, cross intersection L _λupper arbitrfary point B makes intersection L _λtangent line, the angle of this tangent line and vertical plane X2-O2-Z2 is β _b, β _bbetween 0 and β _max(z ₂) between, β _max(z ₂) be along coordinate z ₂the maximum value of β.

Described discontinuous surface of action is the formed secondary envelope surface of the teeth groove side envelope star-wheel flank of tooth, and the discontinuous surface of action in the star-wheel flank of tooth is secondary enveloping surface.The side of described screw rod teeth groove is surface of action envelope moulding in star-wheel flank, and the surface of action of screw rod teeth groove side and star-wheel flank meets envelope meshing condition.

Adopt the advantage of star-wheel flank profile of the present invention and screw rod teeth groove profile to be, in engagement process, Line of contact between star-wheel flank and screw rod alveolar surface moves in the continuous surface of action of star-wheel flank, this engagement pair flank of tooth can make star-wheel be subject to stable oil-film force effect, and can be by the profile of appropriate design tooth front side and tooth rear side, be uniformly distributed the oil film bearing capacity of star-wheel tooth front side and tooth rear side, keep in the course of the work before star-wheel tooth, rear side equates with the gap between teeth groove, make before star-wheel tooth, in rear side clearance, form effective hydrodynamic lubrication, thereby improve reliability and the efficiency of single screw compressor, increase the service life.

Accompanying drawing explanation

Below in conjunction with the drawings and the specific embodiments, the present invention is described in further detail.

Fig. 1 is that single-screw compressor screw coordinates stereogram with star-wheel.

Fig. 2 is star-wheel tooth and the kinematic relation between screw rod teeth groove and the corresponding coordinate system of single helical-lobe compressor intermeshing pair.

Fig. 3 is the expression in star-wheel system of coordinates S2 of the relative velocity of star-wheel flank of tooth arbitrfary point star-wheel and screw rod.

Fig. 4 is star-wheel flank of the present invention and the sight of Plane intersects perpendicular to star-wheel tooth.

Fig. 5 is star-wheel flank of the present invention and the sight that is parallel to the Plane intersects of star-wheel tooth.

Fig. 6 is tooth rear side surface of action and intersection perpendicular to the plane of star-wheel tooth in the embodiment of the present invention 2.

Fig. 7 is N-Side surf after tooth in the embodiment of the present invention 2.

Wherein: the reference character in Fig. 2, Fig. 4-Fig. 7 is: 1, screw rod; 2, star-wheel; 3, star-wheel tooth; 4, star-wheel flank; 5, teeth groove; 6, star-wheel tooth upper surface; 7, tooth top; 8, continuous surface of action; 9, discontinuous surface of action; 10, tooth root; 11, star-wheel lower surface; 12, represent the ellipse I of mesh regional; 13, represent the ellipse II of mesh regional; 14, the tangent line of ellipse; 15, continuous surface of action border.

Embodiment

Single screw compressor star-wheel flank profile should meet conjugation meshing relation with screw rod teeth groove side, on the point of contact of star-wheel flank and screw rod alveolar surface, the relative velocity of star-wheel and screw rod and flank or alveolar surface are tangent at this point, can be expressed as at point of contact first vertical with the normal vector of surface of contact to speed:

v·n=0 (1)

In above formula, v is the relative velocity of point of contact place star-wheel and screw rod, and n is that star-wheel flank or screw rod alveolar surface are at the normal vector at point of contact place.

As shown in Figure 2, position fixing is S1 to the kinematic relation of star-wheel and screw rod, and S3 represents respectively the initial position of star-wheel tooth 3, screw rod teeth groove 5, and moving coordinate system S2 and S4 represent respectively the movement position of star-wheel tooth and screw rod teeth groove.Rotating ratio between star-wheel tooth and screw rod teeth groove is,

$\frac{{\mathrm{\&phi;}}_{\mathrm{sr}}}{{\mathrm{\&phi;}}_{\mathrm{sw}}}=\frac{{\mathrm{\&omega;}}_{\mathrm{sr}}}{{\mathrm{\&omega;}}_{\mathrm{sw}}}=P---\left(2\right)$

Wherein P is the gear ratio of star-wheel 2 and screw rod 1, is generally 11/6.

Can obtain the relative velocity vector (in S2 system of coordinates) at this screw rod and star-wheel:

$v={\mathrm{\&omega;}}_{\mathrm{sw}}\left(\begin{array}{c}-{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">y</figure-callout>}}_2+{\mathrm{<figure-callout\; id="2"\; label="Pz"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Pz</figure-callout>}}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}\\ x_2+{\mathrm{<figure-callout\; id="2"\; label="Pz"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Pz</figure-callout>}}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}\\ \mathrm{Pa}-{\mathrm{<figure-callout\; id="2"\; label="Py"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Py</figure-callout>}}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}-{\mathrm{<figure-callout\; id="2"\; label="Px"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Px</figure-callout>}}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}\end{array}\right)---\left(3\right)$

As shown in Figure 3, A point relative velocity is at the component velocity v of X2O2Z2 plane _αwith the angle of horizontal plane (X2O2Y2) be,

$\mathrm{\&alpha;}=a\tan \left(\frac{\mathrm{Pa}-{\mathrm{<figure-callout\; id="2"\; label="Py"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Py</figure-callout>}}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}-{\mathrm{<figure-callout\; id="2"\; label="Px"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Px</figure-callout>}}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}{y_2-{\mathrm{<figure-callout\; id="2"\; label="Pz"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Pz</figure-callout>}}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}\right)---\left(4\right)$

A point relative velocity is at the component velocity v of horizontal plane (X2O2Y2) _βwith the angle of vertical plane (X2O2Z2) be,

$\mathrm{\&beta;}=a\tan \left(\frac{x_2+{\mathrm{<figure-callout\; id="2"\; label="Pz"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Pz</figure-callout>}}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}}{y_2-{\mathrm{<figure-callout\; id="2"\; label="Pz"\; filenames="HDA0000099492670000012.png"\; state="\{\{state\}\}">Pz</figure-callout>}}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}\right)---\left(5\right)$

The angle range φ of the engagement process culminant star gear teeth _sw∈ [φ _in, φ _out] be given, when providing A point y ₂after coordinate, the size of angle α is along with φ _sw, x ₂and z ₂change, its scope can be defined as [α _min(y ₂), α _max(y ₂)]; When providing A point z ₂after coordinate, the size of angle β is along with φ _sw, x ₂and y ₂change, its scope can be defined as [β _min(z ₂), β _max(z ₂)].This shows, the size and Orientation of A point relative velocity vector all changes within the specific limits.According to the structural feature of single screw compressor, in tooth top 7 positions, (be y ₂value is for star-wheel radius) the interval width [α of angle α _max-α _min] be about 17 °.From tooth top to tooth root, this interval is decreased to zero gradually, in tooth root position alpha _max=α _min.

Conventionally, on the star-wheel flank of tooth, put | x ₂| coordinate is in the 1/2 about facewidth, than | y ₂| much smaller; Because the thickness of star-wheel is in 5～8mm left and right, | z ₂| also than | y ₂| and the centre distance a of screw rod star-wheel is much smaller.The minimum value β of angle β _min(z ₂) can be similar to and be taken as zero.Therefore in the accurate design of the star-wheel flank of tooth, angle β should be between 0 and β _max(z ₂) between.

For the single screw compressor of other form, when the spider gear shaft of single screw compressor and screw axis angle are less than 90 °, the relation of above-mentioned relative velocity is still set up, and still can determine [α _min(y ₂), α _max(y ₂)] and [β _min(z ₂), β _max(z ₂)].

In other words, if the angle of the tangent plane selected at A of the star-wheel flank of tooth and horizontal plane (X2O2Y2) at [α _min(y ₂), α _max(y ₂)] in interval,, in engagement process, must there is a certain star-wheel corner φ _sw, relative velocity that A is ordered is vertical with flank of tooth normal vector meets formula (1), and A point must mesh with screw rod alveolar surface.In Practical Project, can calculate the direction of A point relative velocity according to formula (4) and (5), and construct flank of tooth tangent line or the normal vector direction that corresponding flank of tooth A is ordered, and make it to meet formula (1).

By upper, can conceive following cutting structure: for tooth rear side, approaching star-wheel upper surface place, the flank of tooth and horizontal plane angle are α _min(y ₂); Approaching star-wheel lower surface place, the flank of tooth and horizontal plane angle are α _max(y ₂); From upper surface to lower surface, the angle between the star-wheel flank of tooth and horizontal plane is by α _min(y ₂) fade to α _max(y ₂).For tooth front side, arrange on the contrary, from upper surface to lower surface, the angle between the star-wheel flank of tooth and horizontal plane is by α _max(y ₂) fade to α _min(y ₂).Obviously, for any one star-wheel tooth corner φ _sw, the flank of tooth must exist 1 A to meet formula (1); Or for flank of tooth any point A, must there is a star-wheel tooth corner φ _sw, make it meet formula (1).Like this, the whole flank of tooth all has the chance contacting with screw rod alveolar surface in engagement process.And, in engagement process, the continuous moving in this mesh regional of the Line of contact between star-wheel flank and screw rod alveolar surface.

According to above-mentioned design principle, the continuous envelope cutting structure design proposal of single helical-lobe compressor intermeshing pair of the present invention is as follows:

Star-wheel flank profile is divided into continuous surface of action and discontinuous surface of action two-part; In each star-wheel flank, can have a plurality of being connected or disjunct continuous surface of action, also can only have a continuous surface of action, other parts are discontinuous surface of actions; Surface of action can be distributed to whole star-wheel flank continuously, also can be distributed in the middle of star-wheel flank, and other region is discontinuous surface of action.Screw rod teeth groove curved surface and star-wheel flank surface of action meet conjugate principle, are the envelope surfaces of star-wheel flank surface of action, can by star-wheel flank surface of action, be obtained according to the condition of conjugation engagement.In engagement process, between surface of action 8 and alveolar surface, there is Line of contact continuously, and along with this Line of contact of difference of engaging position moves about in whole continuous surface of action.The continuous surface of action of star-wheel flank and the feature of discontinuous surface of action are as follows:

(1) the Z2 coordinate of establishing the upper and lower surface of star-wheel tooth is respectively z _uand z _d.At star-wheel tooth At The Height, at star-wheel system of coordinates S2, cross (0, y ₂, 0) and point, make a plane γ perpendicular to Y2 axle (perpendicular to star-wheel tooth), intersect and form an intersection with star-wheel flank, this intersection is divided into two-part L _f, L _γ, as shown in Figure 4.Wherein, L _γpart is that plane γ intersects with continuous surface of action 8 intersection forming.Owing to can having one or more continuous surface of action, intersection L on star-wheel flank _γpart can be a line segment, can be also many line segments.When continuous surface of action is distributed to whole star-wheel flank, only there is L _γpart intersection.Therefore, L _γthe Z2 coordinate z of arbitrfary point on part intersection _γspan be z _d≤ z _γ≤ z _u.As intersection L _γwhen part is many line segments, adjacent segments is connected from beginning to end with straightway.In plane γ, cross intersection L _γupper arbitrfary point A makes intersection L _γtangent line, and remember that this tangent line and horizontal plane angle are α _a.This angle α _aalong intersection monotonously change.For tooth rear side, by A point at intersection L _γnear the end points place tangent line of star-wheel upper surface and the angle of horizontal plane, be designated as α _u(y ₂), by A point at intersection L _γnear the end points place tangent line of star-wheel lower surface and the angle of horizontal plane, be designated as α _d(y ₂), when A point is from intersection L _γwhen the end points of the end points the most close past star-wheel lower surface of close star-wheel upper surface moves, the angle α of its tangent line and horizontal plane _afrom α _u(y ₂) monotonously change is α _d(y ₂); For tooth front side, when A point is from intersection L _γwhen the end points of close star-wheel upper surface moves toward another end points, the angle α of its tangent line and horizontal plane (X2O2Y2) _afrom α _d(y ₂) monotonously change is α _u(y ₂).Aforementioned angle meets following relation: α _min(y ₂)≤α _u(y ₂)≤α _d(y ₂)≤α _max(y ₂), available (4) formula calculative determination.

(2) the shape of surface of action of the present invention is not that cylndrical surface neither round platform (cone) face.From intersection L _γupper extreme point to lower extreme point, its curvature changes.

(3) in above-mentioned two-part intersection, L _fpart is the intersection of plane γ and discontinuous surface of action 9.Considering that star-wheel flank exists one or more continuous surface of actions, also may there is one or more in discontinuous surface of action.Therefore, L _fpart intersection also may be comprised of one or more of line segments., there is L in the intersection at continuous surface of action and discontinuous surface of action _fintersection and L _γthe intersection point of intersection.In plane γ, cross intersection point and make respectively L _fintersection and L _γthe tangent line of intersection, and by this L _ftangent line and the angle of horizontal plane (X2O2Y2) be denoted as α _jf, by this L _γtangent line and the angle of horizontal plane (X2O2Y2) be denoted as α _{j γ}.The postive direction of definition Z2 axle is top, and the negative direction of Z2 axle is below.For tooth rear side, if L _γintersection is at L _fthe below of intersection, at their intersection point place, α _jf≤ α _{j γ}; If L _γintersection is at L _fthe top of intersection, at their intersection point place, α _{j γ}≤ α _jf.For tooth front side, if L _γintersection is at L _fthe below of intersection, at their intersection point place, α _{j γ}≤ α _jf; If L _γintersection is at L _fthe top of intersection, at their intersection point place, α _jf≤ α _{j γ}.

(4), when plane γ moves from tooth top 7 to tooth root 10, there is following variation in the length ratio of above-mentioned two-part intersection: at tooth top, and L _ftotal length compared with L _γlength little, minimum can be zero; At tooth root place, L _flength large or equate compared with tooth top place, minimum also can be zero; Between tooth top and tooth root, L _flength all between it between tooth top and the length at tooth root place.That is, the width of the continuous surface of action of star-wheel flank reduces toward tooth root direction gradually from tooth top.

(5) coordinate of establishing the Y2 of tooth root place flank is y _g, the coordinate of the Y2 of tooth top place flank is y _d, from star-wheel tooth root to tooth top, flank Y2 coordinate is from y _gincrease to y _d.At star-wheel tooth thickness, be in star-wheel system of coordinates S2 and cross (0,0, z ₂) point, do one perpendicular to the Z2 axle plane λ of (being parallel to star-wheel), intersect and form an intersection with star-wheel flank, this intersection is divided into two-part, and a part is the intersection L of plane λ and continuous surface of action _λ, another part is the intersection L of plane λ and discontinuous surface of action _g, as shown in Figure 5.In plane λ, cross intersection L _λupper arbitrfary point B makes intersection L _λtangent line, the angle of this tangent line and vertical plane (X2O2Z2) is β _b, and β _bbetween 0 and β _max(z ₂) between.

Determine after the continuous surface of action of star-wheel flank, according to envelope meshing condition, determine screw rod teeth groove profile.The curved surface that meets the various shapes of above-mentioned condition all can be used as the discontinuous surface of action of star-wheel flank.This curved surface can be used configured in various manners, as used the methods such as curve sweeping, setting-out.Especially, can also construct by the mode of twice-enveloping, determine after screw rod teeth groove profile, with screw rod alveolar surface envelope star-wheel flank, outside the continuous surface of action of star-wheel flank, form secondary enveloping surface, formed secondary enveloping surface can be used as the discontinuous surface of action of star-wheel flank, jointly forms star-wheel flank with original continuous surface of action.

The such scheme that the present invention adopts, its star-wheel flank profile can be used numerical control milling machine machine shaping, its screw rod teeth groove profile can be by numerical control milling machine or lathe in machining moulding, can also design specialized numerical control milling machine or machined into star-wheel flank profile and screw rod teeth groove profile.

Below for two specific design examples of envelope Profile of AT (not forming limiting the scope of the invention) of single helical-lobe compressor intermeshing pair of the present invention.

Embodiment 1

Referring to Fig. 4, Fig. 5.If the Z2 coordinate on the upper and lower surface of star-wheel is respectively z _u, z _d; The Y2 coordinate of star-wheel tooth root and tooth top is respectively y _g, y _d.The continuous surface of action of star-wheel flank of the present invention and intersection L perpendicular to the plane of star-wheel tooth _γcan be expressed as,

$\left\{\begin{array}{c}{x}_2=f(z,y)\\ y_2=y\\ z_2=z\end{array}\right.$

The tangent line of above formula curve and the angle of horizontal plane are α, and α meets,

α _min(y _d)≤α≤α _max(y _d)，z _d≤z≤z _u

And, work as z=z _dand z _utime get respectively the equal sign of maximum value and minimum value; Wherein, span α _min(y _d) and α _max(y _d) according to formula (4), determine.

At tooth root place,

α=α _max(y _g)=α _min(y _g)

For tooth front side and tooth rear side, difference curve construction function f (z, y).The form of this curve can be any form curve of ellipse, hyperbola, parabola, exponential curve, natural logarithm curve etc., can be also the combination of various forms curve.

According to the mathematical expression of star-wheel tooth surface of action, according to envelope meshing condition, obtain the geometric parameter of teeth groove side, can set up according to these parameters the threedimensional model of teeth groove profile, numerical programming procedure.

Embodiment 2

Referring to Fig. 6, Fig. 7, the continuous surface of action of star-wheel rear flank of the present invention has two, and each surface of action is a part for the ellipsoid that scans along star-wheel tooth (Y2 direction) of ellipse.At given star-wheel tooth height position y ₂, perpendicular to the plane of star-wheel tooth and the intersection of every surface of action, be all a part for ellipse, two oval positions, shape are different, and ellipse 1 is designated as to α near the end points place tangent line of star-wheel upper surface and the angle of horizontal plane _u1(y ₂), ellipse 1 is designated as α near the end points place tangent line of star-wheel lower surface and the angle of horizontal plane _d1(y ₂), ellipse 2 is designated as α near the end points place tangent line of star-wheel upper surface and the angle of horizontal plane _u2(y ₂), ellipse 2 is designated as α near the end points place tangent line of star-wheel lower surface and the angle of horizontal plane _d2(y ₂), these angles meet following relation: α _min(y ₂)≤α _u1(y ₂)≤α _d1(y ₂)≤α _u2(y ₂)≤α _u2(y ₂)≤α _max(y ₂).Scope [α wherein _min(y ₂), α _max(y ₂)] according to formula (4), calculate and try to achieve.

The actual product of manufacturing by engagement pair profile of the present invention, the results showed, after time in operation more than 200 hours, the continuous surface of action region of star-wheel flank is more smooth, bright than the region of discontinuous surface of action, can under illumination condition, directly recognize the continuous mesh regional of star-wheel flank.

Claims (6)

1. the envelope Profile of AT of a single helical-lobe compressor intermeshing pair is constructed, comprise the side of star-wheel tooth and the side of screw rod teeth groove, its screw rod teeth groove side is the envelope surface of star-wheel flank, it is characterized in that: star-wheel flank is comprised of continuous surface of action and two kinds of curved surfaces of discontinuous surface of action; Wherein, continuously surface of action is the mesh regional of star-wheel flank and screw rod teeth groove side, continuous surface of action at least one, the surface except continuous surface of action is discontinuous surface of action; In star-wheel tooth root position, surface of action reduced width is zero continuously; In engagement process, the Line of contact of star-wheel flank and screw rod teeth groove side is moving in surface of action continuously; Wherein, the all plane γs vertical with star-wheel tooth and continuously surface of action intersect formation intersection, the feature of the tangent line of each intersection in the plane vertical with described star-wheel tooth is: the end points from this intersection near the extremely close star-wheel lower surface of end points of star-wheel upper surface, and all tangent lines are monotonously change with the angle that is parallel to the horizontal plane λ on the upper and lower surface of star-wheel; This friendship curvature of a curve gradually changes.

2. the envelope Profile of AT of single helical-lobe compressor intermeshing pair as claimed in claim 1 is constructed, it is characterized in that: described from this intersection near the end points of star-wheel upper surface to the end points near star-wheel lower surface, tangent line with the span of angle of horizontal plane λ that is parallel to the upper and lower surface of star-wheel by the determined scope [α of following formula _min, α _max] within:

$\mathrm{\&alpha;}=a\tan \left(\frac{\mathrm{Pa}-{\mathrm{Py}}_2{\cos \mathrm{\&phi;}}_{\mathrm{sw}}-{\mathrm{Px}}_2{\sin \mathrm{\&phi;}}_{\mathrm{sw}}}{y_2-{\mathrm{Pz}}_2{\sin \mathrm{\&phi;}}_{\mathrm{sw}}}\right)$

In formula: φ _swfor the angle range of star-wheel tooth, the ratio of the groove number of the number of teeth that P is star-wheel and screw rod, a is the centre distance of star-wheel and screw rod, x ₂, y ₂, z ₂coordinate for certain point on intersection; φ _swangle range be that point on intersection can the span of the star-wheel tooth corner of engagement occur with screw rod teeth groove side, within the scope of this, according to above formula, seek out the scope [α at α angle _min, α _max].

3. the envelope Profile of AT of single helical-lobe compressor intermeshing pair as claimed in claim 1 is constructed, it is characterized in that: star-wheel teeth groove side with perpendicular to the plane γ of star-wheel tooth, intersect the intersection forming and be divided into two kinds, a kind of is continuous surface of action and intersection L perpendicular to star-wheel tooth plane γ _γ, another is discontinuous surface of action and intersection L perpendicular to star-wheel tooth plane γ _f, two kinds of intersection sections interconnect at the intersection of continuous surface of action and discontinuous surface of action, and become a whole piece intersection section of star-wheel flank; At the plane γ vertical with star-wheel tooth, cross the tangent line that same tie point is made respectively aforementioned two-part intersection, and by L _ftangent line and the angle of horizontal plane X2-O2-Y2 be denoted as α _jf, by L _γtangent line and the angle of horizontal plane X2-O2-Y2 be denoted as α _{j γ}, the postive direction of definition Z2 axle is top, the negative direction of Z2 axle is below, for tooth rear side, if L _γat L _fbelow, at their intersection point place, α _jf≤ α _{j γ}; If L _γat L _ftop, at their intersection point place, α _{j γ}≤ α _jf; For tooth front side, if L _γat L _fthe below of intersection, at their intersection point place, α _{j γ}≤ α _jf; If L _γat L _ftop, at their intersection point place, α _jf≤ α _{j γ}.

4. the envelope Profile of AT of single helical-lobe compressor intermeshing pair as claimed in claim 1 is constructed, it is characterized in that: described in be parallel to the horizontal plane λ on the upper and lower surface of star-wheel and star-wheel flank and intersect and form an intersection, this intersection is divided into two-part, and a part is the intersection L of plane λ and continuous surface of action _λ, another part is the intersection L of plane λ and discontinuous surface of action _g, in plane λ, cross intersection L _λupper arbitrfary point B makes intersection L _λtangent line, the angle of this tangent line and vertical plane X2-O2-Z2 is β _b, β _bbetween 0 and β _max(z ₂) between, β _max(z ₂) be along coordinate z ₂the maximum value of β, β is that this relative velocity is at the component velocity of horizontal plane and the angle of vertical plane.

5. the envelope Profile of AT of single helical-lobe compressor intermeshing pair as claimed in claim 1 is constructed, it is characterized in that: described discontinuous surface of action is the formed secondary envelope surface of the teeth groove side envelope star-wheel flank of tooth, and the discontinuous surface of action in the star-wheel flank of tooth is secondary enveloping surface.

6. the envelope Profile of AT of single helical-lobe compressor intermeshing pair as claimed in claim 1 is constructed, it is characterized in that: the side of described screw rod teeth groove is surface of action envelope moulding in star-wheel flank, and the surface of action of screw rod teeth groove side and star-wheel flank meets envelope meshing condition.

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