CN102338091A - 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 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 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 type work, double-screw compressor, has advantages such as simple in structure, that running is reliable, volume is little, in light weight, noise is low.

State's external enwergy Manufacture Order screw air compressor company surplus method, day, English, U.S.A, the Holland etc. ten arranged, some producers of China also begin the Manufacture Order helical-lobe compressor in recent years, but its performance index are general not as good as imported product.Particularly using under the situation of same material, and the Japanese star-wheel life-span is about 2 times of China.At present, generally believe that this is the difference that the machining accuracy by single helical-lobe compressor intermeshing pair causes.The incomplete statistics of the Chinese compressor of certificate association, about 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 in Shanghai Sheng company again is that a tame international style compressor is made company, behind its auxiliary system of main frame outfit of Mitsui company purchase single screw compressor, supplies the domestic and international market with high price now always.Therefore, single screw compressor has huge development space at home.But the star-wheel odontotripsis is fast, and working life, short problem became domestic two to be difficult to the obstacle gone beyond during the last ten years all the time.

The core component of single screw compressor is the engagement pair (Fig. 1) that is made up of screw rod, star-wheel, and its processing is the maximum place of difficulty in the single screw compressor part processing.And the molded lines of engagement pair is very big to processing method and difficulty of processing influence.Disclosed abroad single screw compressor molded lines has two kinds of lines enveloping and cylindrical envelopes.Domestic someone once proposes the molded lines of twice-enveloping type, but all owing to processing problems still is unrealized.

Summary of the invention

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

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

A kind of envelope Profile of AT 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: the mesh regional of the star-wheel flank of engagement pair and screw rod teeth groove side is continuous surface of action; The star-wheel flank is made up of continuous surface of action and two kinds of curved surfaces of discontinuous surface of action, 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 that continuous surface of action then is discontinuous surface of action; In the tooth root position, the surface of action reduced width is zero continuously; In the 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 plane γ vertical with the star-wheel tooth and the continuous surface of action of star-wheel flank intersect the formation intersection; The characteristics of the tangent line of this intersection in the vertical plane of said star-wheel tooth are: to lower extreme point, tangent line is a monotonously change with the angle that is parallel to the horizontal plane λ on the upper and lower surface of star-wheel from the upper extreme point of this intersection; To lower extreme point, its curvature gradually changes from the upper extreme point of this intersection.

In the such scheme, said upper extreme point from this intersection is to lower extreme point, and the span of tangent line and the angle of the horizontal plane λ that is parallel to the upper and lower surface of star-wheel is at the scope [α that confirms by following formula _Min, α _Max] within:

$\mathrm{\&alpha;}=a\tan \left(\frac{\mathrm{Pa}-\mathrm{<figure-callout\; id="2"\; label="P\; y"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{y}_{}{}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}-P{x}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}{y_2-\mathrm{<figure-callout\; id="2"\; label="P\; z"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{z}_{}{}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}\right)$

In the formula: φ _SwBe the angle range of star-wheel tooth, P is the ratio of groove number of the number of teeth and the screw rod of star-wheel, x ₂, y ₂, z ₂Coordinate for certain point on the intersection; φ _SwAngle range be the span that the star-wheel tooth corner of engagement can take place with the screw rod alveolar surface for point on the intersection, in this scope, seek out the scope [α at α angle according to following formula _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, a kind of in addition 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 linking to each other before and after all intersection sections constitutes whole piece intersections of star-wheel flanks; Plane γ vertical with the star-wheel tooth crosses the tangent line that same tie point is made aforementioned two-part intersection respectively, and with L _fThe angle note of tangent line and horizontal plane X2-O2-Y2 make α _Jf, with L _γThe angle note of tangent line and horizontal plane X2-O2-Y2 make α _{J γ}, the postive direction of definition Z2 axle is the top, the negative direction of Z2 axle is the below, for the tooth rear side, if L _γAt L _fThe below, then at their intersection point place, α _Jf≤α _{J γ}If L _γAt L _fThe top, then at their intersection point place, α _{J γ}≤α _JfFor the tooth front side, if L _γAt L _fThe below of intersection is then at their intersection point place, α _{J γ}≤α _JfIf L _γAt L _fThe top, then at their intersection point place, α _Jf≤α _{J γ}

Said 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 the λ of plane, cross intersection L _λLast 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.

Said discontinuous surface of action is the formed secondary envelope surface of the teeth groove side envelope star-wheel flank of tooth, and promptly the discontinuous surface of action in the star-wheel flank of tooth is a secondary enveloping surface.The side of said screw rod teeth groove is that promptly the surface of action of screw rod teeth groove side and star-wheel flank satisfies the envelope meshing condition by the surface of action envelope moulding in the star-wheel flank.

Adopt the advantage of star-wheel flank profile of the present invention and screw rod teeth groove profile to be; In engagement process, the Line of contact between star-wheel flank and the screw rod alveolar surface moves in the continuous surface of action of star-wheel flank, and this engagement pair flank of tooth can make star-wheel receive stable oil-film force effect; And can be through the profile of appropriate design tooth front side and tooth rear side; The even oil film bearing capacity of distribution star-wheel tooth front side and tooth rear side keeps the forward and backward side of star-wheel tooth to equate with gap between teeth groove in the course of the work, makes the effective hydrodynamic lubrication of the interior formation of the forward and backward side clearance of star-wheel tooth; Thereby improve the reliability and the efficient of single screw compressor, increase the service life.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is made further detailed description.

Fig. 1 is that the single screw compressor screw rod cooperates stereogram with star-wheel.

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

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

Fig. 4 is star-wheel flank of the present invention and sight perpendicular to the Plane intersects of 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 a tooth rear side surface of action and intersection perpendicular to the plane of star-wheel tooth in the embodiment of the invention 2.

Fig. 7 is a N-Side surf behind the tooth in the embodiment of the invention 2.

Wherein: the reference character among 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 satisfy the conjugation meshing relation with screw rod teeth groove side; Promptly 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 earlier vertical with the normal vector of surface of contact to speed:

v·n＝0 (1)

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

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

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

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

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

$v={\mathrm{\&omega;}}_{\mathrm{sw}}\left(\begin{array}{c}-{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">y</figure-callout>}}_2+\mathrm{<figure-callout\; id="2"\; label="P\; z"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{z}_{}{}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}\\ x_2+\mathrm{<figure-callout\; id="2"\; label="P\; z"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{z}_{}{}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}\\ \mathrm{Pa}-\mathrm{<figure-callout\; id="2"\; label="P\; y"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{y}_{}{}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}-P{x}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}\end{array}\right)---\left(3\right)$

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

$\mathrm{\&alpha;}=a\tan \left(\frac{\mathrm{Pa}-\mathrm{<figure-callout\; id="2"\; label="P\; y"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{y}_{}{}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}-P{x}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}{y_2-\mathrm{<figure-callout\; id="2"\; label="P\; z"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{z}_{}{}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}\right)---\left(4\right)$

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

$\mathrm{\&beta;}=a\tan \left(\frac{x_2+\mathrm{<figure-callout\; id="2"\; label="P\; z"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{z}_{}{}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}}{y_2-\mathrm{<figure-callout\; id="2"\; label="P\; z"\; filenames="HDA0000099492670000012.png,HDA0000099492670000023.png"\; state="\{\{state\}\}">P</figure-callout>}{z}_{}{}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}\right)---\left(5\right)$

The angle range φ of the engagement process culminant star gear teeth _Sw∈ [φ _In, φ _Out] be given, when providing A point y ₂Behind the coordinate, the size of angle is along with φ _Sw, x ₂And z ₂Change, its scope can be confirmed as [α _Min(y ₂), α _Max(y ₂)]; When providing A point z ₂Behind the coordinate, the size of angle β is along with φ _Sw, x ₂And y ₂Change, its scope can be confirmed as [β _Min(z ₂), β _Max(z ₂)].This shows that 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, (be y in tooth top 7 positions ₂Value is for the star-wheel radius) the interval width [α of angle _Max-α _Min] be about 17 °.From the tooth top to the tooth root, this interval is decreased to zero gradually, promptly in the tooth root position alpha _Max=α _Min

Usually, put on the star-wheel flank of tooth | x ₂| coordinate is about 1/2 facewidth, than | y ₂| much little; Because the thickness of star-wheel is about 5～8mm, | z ₂| also than | y ₂| much little with the centre distance a of screw rod star-wheel.The minimum value β of angle β _Min(z ₂) can be similar to and be taken as zero.So in the precise 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 during less than 90 °, the relation of above-mentioned relative velocity is still set up, and still can confirm [α _Min(y ₂), α _Max(y ₂)] and [β _Min(z ₂), β _Max(z ₂)].

In other words, if the angle of tangent plane that the star-wheel flank of tooth is selected at A and horizontal plane (X2O2Y2) at [α _Min(y ₂), α _Max(y ₂)] in the interval, then in engagement process, must there be a certain star-wheel corner φ _Sw, the relative velocity that A is ordered is vertical with flank of tooth normal vector to satisfy formula (1), and promptly the A point must mesh with the screw rod alveolar surface.Can calculate the direction of A point relative velocity according to formula (4) and (5) in the actual engineering, and construct flank of tooth tangent line or the normal vector direction that corresponding flank of tooth A is ordered, and make it to satisfy formula (1).

By last, can conceive like the Dedendum surface structure: for the tooth rear side, near star-wheel upper surface place, the flank of tooth and horizontal plane angle are α _Min(y ₂); Near star-wheel lower surface place, the flank of tooth and horizontal plane angle are α _Max(y ₂); To lower surface, the angle between the star-wheel flank of tooth and the horizontal plane is by α from upper surface _Min(y ₂) fade to α _Max(y ₂).For the tooth front side, then be provided with on the contrary, to lower surface, the angle between the star-wheel flank of tooth and the horizontal plane is by α from upper surface _Max(y ₂) fade to α _Min(y ₂).Obviously, for any star-wheel tooth corner φ _Sw, the flank of tooth must exist 1 A to satisfy formula (1); Perhaps, must there be a star-wheel tooth corner φ for any 1 A of the flank of tooth _Sw, make it satisfy formula (1).Like this, whole tooth surface all has the chance that contacts with the screw rod alveolar surface in engagement process.And in the engagement process, the Line of contact between star-wheel flank and the screw rod alveolar surface moves in this mesh regional continuously.

According to above-mentioned design principle, the continuous envelope flank of tooth structural design scheme of single helical-lobe compressor intermeshing pair of the present invention is following:

Star-wheel flank profile is divided into continuous surface of action and discontinuous surface of action two-part; A plurality of linking to each other or disjunct continuous surface of action can be arranged in each star-wheel flank, also can have only a continuous surface of action, other part then is discontinuous surface of action; Surface of action can be distributed to whole star-wheel flank continuously, also can be distributed in the middle of the star-wheel flank, and other zone then is discontinuous surface of action.Screw rod teeth groove curved surface and star-wheel flank surface of action satisfy conjugate principle, are the envelope surfaces of star-wheel flank surface of action, can be obtained by star-wheel flank surface of action according to the condition of conjugation engagement.In the engagement process, there is Line of contact between surface of action 8 and the alveolar surface 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 characteristic of discontinuous surface of action are following:

(1) the Z2 coordinate of establishing the upper and lower surface of star-wheel tooth is respectively z _uAnd z _dThe star-wheel tooth highly be in star-wheel system of coordinates S2 cross (0, y ₂, 0) and point, make a plane γ perpendicular to Y2 axle (promptly perpendicular to the star-wheel tooth), intersect intersection of formation with the 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 the intersections that form with continuous surface of action 8.Owing to one or more continuous surface of action can be arranged, intersection L on the star-wheel flank _γPart can be a line segment, also can be many line segments.When continuous surface of action is distributed to whole star-wheel flank, only there is L _γThe part intersection.So, L _γThe Z2 coordinate z of arbitrfary point on the part intersection _γSpan be z _d≤z _γ≤z _uAs intersection L _γWhen part is many line segments, adjacent segments is connected with straightway from beginning to end.In the γ of plane, cross intersection L _γLast arbitrfary point A makes intersection L _γTangent line, and remember that this tangent line and horizontal plane angle are α _AThis angle _AAlong the intersection monotonously change.For the tooth rear side, with the A point at intersection L _γBe designated as α near the end points place tangent line of star-wheel upper surface and the angle of horizontal plane _u(y ₂), with the A point at intersection L _γBe designated as α near the end points place tangent line of star-wheel lower surface and the angle of horizontal plane _d(y ₂), when the A point from intersection L _γNear the end points of star-wheel upper surface when moving near the end points of star-wheel lower surface, the angle of its tangent line and horizontal plane _AFrom α _u(y ₂) monotonously change is α _d(y ₂); For the tooth front side, when the A point from intersection L _γWhen moving near past another end points of the end points of star-wheel upper surface, the angle of its tangent line and horizontal plane (X2O2Y2) _AFrom α _d(y ₂) monotonously change is α _u(y ₂).Aforementioned angle satisfies following relation: α _Min(y ₂)≤α _u(y ₂)≤α _d(y ₂)≤α _Max(y ₂), available (4) formula is calculated and is confirmed.

(2) shape of surface of action of the present invention promptly is not that the cylndrical surface neither round platform (awl) 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.Consider that there are one or more continuous surface of actions in the star-wheel flank, also possibly there is one or more in discontinuous surface of action.Therefore, L _fThe part intersection also possibly be made up of one or many line segments.There is L in intersection at continuous surface of action and discontinuous surface of action _fIntersection and L _γThe intersection point of intersection.In the γ of plane, cross intersection point and make L respectively _fIntersection and L _γThe tangent line of intersection, and with this L _fThe angle note of tangent line and horizontal plane (X2O2Y2) make α _Jf, with this L _γThe angle note of tangent line and horizontal plane (X2O2Y2) make α _{J γ}The postive direction of definition Z2 axle is the top, and the negative direction of Z2 axle is the below.For the tooth rear side, if L _γIntersection is at L _fThe below of intersection is then at their intersection point place, α _Jf≤α _{J γ}If L _γIntersection is at L _fThe top of intersection is then at their intersection point place, α _{J γ}≤α _JfFor the tooth front side, if L _γIntersection is at L _fThe below of intersection is then at their intersection point place, α _{J γ}≤α _JfIf L _γIntersection is at L _fThe top of intersection is then at their intersection point place, α _Jf≤α _{J γ}

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

(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, then from the star-wheel tooth root to tooth top, flank Y2 coordinate is from y _gIncrease to y _dStar-wheel tooth thickness be in star-wheel system of coordinates S2 cross (0,0, z ₂) point, do one perpendicular to the Z2 axle plane λ of (promptly being parallel to star-wheel), intersect intersection of formation with the 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 the λ of plane, cross intersection L _λLast 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.

After confirming the continuous surface of action of star-wheel flank,, confirm screw rod teeth groove profile according to the envelope meshing condition.The curved surface that satisfies the different shape 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 sweep methods such as summary, setting-out with curve.Special; Can also construct through the mode of twice-enveloping; After promptly confirming screw rod teeth groove profile,, outside the continuous surface of action of star-wheel flank, form secondary enveloping surface with screw rod alveolar surface envelope star-wheel flank; Formed secondary enveloping surface can be used as the discontinuous surface of action of star-wheel flank, forms the star-wheel flank jointly 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 special numerical control milling machine or machined into star-wheel flank profile and screw rod teeth groove profile.

Below for two concrete design examples of envelope Profile of AT (not constituting restriction) of single helical-lobe compressor intermeshing pair of the present invention to protection domain 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 _dThe Y2 coordinate of star-wheel tooth root and tooth top is respectively y _g, y _dContinuous 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 following formula curve and the angle of horizontal plane are α, and α satisfies,

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

And, work as z=z _dAnd z _uThe time get the equal sign of maximum value and minimum value respectively; Wherein, span α _Min(y _d) and α _Max(y _d) confirm according to formula (4).

At the tooth root place,

α＝α _max(y _g)＝α _min(y _g)

For tooth front side and tooth rear side, and 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 or the like, also can be the combination of various forms curve.

According to the mathematical expression of star-wheel tooth surface of action,, can set up the threedimensional model of teeth groove profile according to these parameters, the establishment nc program according to the geometric parameter of envelope meshing condition acquisition teeth groove side.

Embodiment 2

Referring to Fig. 6, Fig. 7, the continuous surface of action of star-wheel rear flank of the present invention has two, the part of each surface of action ellipsoid that all to be ellipse scan along star-wheel tooth (Y2 direction).At given star-wheel tooth height position y ₂, all be the part of ellipse perpendicular to the plane of star-wheel tooth and the intersection of every surface of action, two oval positions, shape are different, and ellipse 1 is designated as 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 satisfy 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)] try to achieve according to formula (4) calculating.

Actual product by engagement pair profile manufacturing of the present invention; The results showed; After the time of operation more than 200 hours; The continuous surface of action zone of star-wheel flank is regional more smooth, bright than 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; 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: the mesh regional of the star-wheel flank of engagement pair and screw rod teeth groove side is continuous surface of action, and the star-wheel flank is made up of continuous surface of action and two kinds of curved surfaces of discontinuous surface of action; Wherein, continuously surface of action at least one, the surface except that continuous surface of action then is discontinuous surface of action; In the tooth root position, the surface of action reduced width is zero continuously; In the engagement process, the Line of contact of star-wheel flank and screw rod teeth groove side is moving in the surface of action continuously; Wherein, The plane γ vertical with the star-wheel tooth intersects the formation intersection with continuous surface of action; The characteristics of the tangent line of this intersection in the vertical plane of said star-wheel tooth are: to lower extreme point, tangent line is a monotonously change with the angle that is parallel to the horizontal plane λ on the upper and lower surface of star-wheel from the upper extreme point of this intersection; To lower extreme point, its curvature gradually changes from the upper extreme point of this intersection.

2. the envelope Profile of AT of single helical-lobe compressor intermeshing pair as claimed in claim 1; It is characterized in that: said upper extreme point from this intersection is to lower extreme point, and the span of tangent line and the angle of the horizontal plane λ that is parallel to the upper and lower surface of star-wheel is by the determined scope [α of following formula _Min, α _Max] within:

$\mathrm{\&alpha;}=a\tan \left(\frac{\mathrm{Pa}-P{y}_2\cos {\mathrm{\&phi;}}_{\mathrm{sw}}-P{x}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}{y_2-P{z}_2\sin {\mathrm{\&phi;}}_{\mathrm{sw}}}\right)$

In the formula: φ _SwBe the angle range of star-wheel tooth, P is the ratio of groove number of the number of teeth and the screw rod of star-wheel, x ₂, y ₂, z ₂Coordinate for certain point on the intersection; φ _SwAngle range be the span that the star-wheel tooth corner of engagement can take place with the screw rod alveolar surface for point on the intersection, in this scope, seek out the scope [α at α angle according to following formula _Min, α _Max].

3. the envelope Profile of AT of single helical-lobe compressor intermeshing pair as claimed in claim 1; It is characterized in that: the star-wheel flank with intersect the intersection that forms perpendicular to the plane γ of star-wheel tooth 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, a kind of in addition 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; Plane γ vertical with the star-wheel tooth crosses the tangent line that same tie point is made aforementioned two-part intersection respectively, and with L _fThe angle note of tangent line and horizontal plane X2-O2-Y2 make α _Jf, with L _γThe angle note of tangent line and horizontal plane X2-O2-Y2 make α _{J γ}, the postive direction of definition Z2 axle is the top, the negative direction of Z2 axle is the below, for the tooth rear side, if L _γAt L _fThe below, then at their intersection point place, α _Jf≤α _{J γ}If L _γAt L _fThe top, then at their intersection point place, α _{J γ}≤α _JfFor the tooth front side, if L _γAt L _fThe below of intersection is then at their intersection point place, α _{J γ}≤α _JfIf L _γAt L _fThe top, then 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; It is characterized in that: said horizontal plane λ and the star-wheel flank that is parallel to the upper and lower surface of star-wheel intersects intersection of formation; 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 the λ of plane, cross intersection L _λLast 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.

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

6. the envelope Profile of AT of single helical-lobe compressor intermeshing pair as claimed in claim 1; It is characterized in that: the side of said screw rod teeth groove is that promptly the surface of action of screw rod teeth groove side and star-wheel flank satisfies the envelope meshing condition by the surface of action envelope moulding in the star-wheel flank.

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