CN1363771A - Tooth-shaped screw bolt - Google Patents

Abstract

A toothed screw bolt used in screw bolt pump features that its profile of tooth has arc, extended involute and elongated cycloid, so it is easily machined. Its advantages include high precision of screw bolt and efficiency, less leakage and noise, high pressure, small size and compact structure.

Description

A kind of tooth-shaped screw bolt

Technical field

The present invention relates to the screw rod in a kind of FLUID TRANSPORTATION pump, especially refer to the technical field of the tooth-shaped screw bolt in a kind of screw pump.

Background technique

Existing screw pump generally has three kinds of forms, promptly single screw rod, twin-screw and three screw rods.Then man and Qi Zongliang write in " rotary compressor and the pump " of publication as can be known in April nineteen ninety-five by bear, the screw rod of helical rotor pump is eccentric to be provided with, the cross section of lining is the shape that is similar to the stadium of track and field runway by two semicircles and two sections rectilinear(-al)s, its inner chamber is the two-wire inner helical surface, so its processing technology complexity, the discharge pressure during fed sheet of a media is also low.For this reason, a kind of pump of twin-screw is devised, as " the two screw pump screw rod " of China Patent No. 99201251 and the patent No. 96236524 " a kind of tooth screw stem " with novel tooth form molded lines, the former screw rod adopts the cycloidal tooth profile structure, though raising discharge pressure that can be by a relatively large margin, its technology capability is still very poor; And the latter's screw rod adopts Archimedes's tooth shape of screw, and its manufacturability is better, but performance and versatility are not very desirable.At present most widely used is three screw pump, though this pump stressing conditions is good, and because of three screw rods are arranged, the structure relative complex, driving and driven rod-shape differs, is difficult for processing, and elongated from bar, poor rigidity also will be subjected to the restriction of pressure bar stabilization.

Summary of the invention

Technical problem to be solved by this invention is to overcome above-mentioned defective, a kind of good manufacturability is provided, leak little, working pressure height, the tooth-shaped screw bolt that operates steadily.

The present invention solves the problems of the technologies described above the technological scheme that is adopted: the curve abcde in this tooth-shaped screw bolt is the tooth curve on the screw rod radial cross section, a, e are on top circle, c, d are on root circle, curve ae is the circular arc of top circle, curve cd is the circular arc of root circle, it is characterized in that described curve ab is a prolate involute, and curve bc is a superior trochoid, curve ed is a superior trochoid, and the length of described screw rod is greater than the length of two pitch.

The curve shape of described superior trochoid bc, ed is identical, and direction is opposite.

The generation type of described each curve is as follows:

(1) formation of superior trochoid ed:

x＝Rsin2ψ-2rsinψ

y＝rcos2ψ-Rcos2ψ $\mathrm{\ρ}=\sqrt{x^2+y^2}$ $\mathrm{\β}=\arccos \frac{{\mathrm{\ρ}}^2+{4r}^2-R^2}{4\mathrm{r\ρ}}$ $\mathrm{\ψ}=\arccos \frac{{4r}^2+r^2-{\mathrm{\ρ}}^2}{4\mathrm{Rr}}$

In φ=β-ψ formula: the right angled coordinates of any point on x, the y-flank profil

The polar radius vector and the corner of any point on p, the φ-flank profil

R, R ₀, r-top circle, root circle and Pitch radius

ψ-pitch circle II is with respect to the corner of pitch circle I

The formation of β-utmost point footpath and angle (2) the superior trochoid bc of the two screw rods line of centres:

x＝-Rsin(2ψ-φ _α)+2rsin(2ψ-φ _α)

y＝-Rcos(2ψ-φ _α)+2rcos(2ψ-φ _α)

φ＝ψ-β ${\mathrm{\φ}}_{\mathrm{\α}}=\mathrm{\π}-\frac{1}{2}[{\cos }^{-1}\frac{{\mathrm{ob}}^2+{4r}^2-R^2}{4r\·\mathrm{ob}}-{\cos }^{-1}\frac{{4r}^2+R^2-{\mathrm{ob}}^2}{4\mathrm{Rr}}+\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{R}\right)$ $-{\cos }^{-1}\frac{R_0}{R}-\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{\mathrm{ob}}\right)+{\cos }^{-1}\frac{R_0}{\mathrm{ob}}]$ $\mathrm{ob}=\sqrt{R_0^2+{(2\sqrt{r^2-R_0^2}-\sqrt{R^2-R_0^2})}^2}$ In the formula: φ _αThe polar angle at-prolate involute ab and top circle intersection point a place

The formation of utmost point footpath (3) the top circle ae at ob-b place: $R=\sqrt{x^2+y^2}$ (4) formation of root circle cd: $R_0=\sqrt{x^2+y^2}$ (5) formation of prolate involute ab: $\mathrm{\&rho;}=\frac{R_0}{\cos \mathrm{\&alpha;}\cos \mathrm{\&gamma;}}$ ${\mathrm{\&phi;}}_{\mathrm{\&alpha;}}=\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{R}\right)-{\cos }^{-1}\frac{R_0}{R}-\mathrm{\&phi;}=\mathrm{tg\&alpha;}-\mathrm{\&alpha;}$ $({\mathrm{\&phi;}}_{\mathrm{\&alpha;}}\&le;\mathrm{\&phi;}<{\mathrm{\&phi;}}_{\mathrm{\&alpha;}}+\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{R}\right)-{\cos }^{-1}\frac{R_0}{R}$ In the formula: the pressure angle of α-prolate involute ab

The helix angle of the helicoid of γ-screw rod compared with prior art the invention has the advantages that: owing to adopted prolate involute and superior trochoid structure, so easy processing, be convenient to produce in batches; Moreover, can also improve the screw rod precision, make the leakage rate of screw pump little, efficient, pressure height operate steadily, and noise is low; Compare with three screw pump, only need a pitch just can have Seal cage of one's own, so size is little, compact structure, and rigidity height.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a radial cross section schematic representation of the present invention;

Fig. 3 is two screw rods of the present invention engagement schematic representation when making pure rolling;

Fig. 4 is two screw rods of the present invention pitch curve schematic representation when making pure rolling;

Fig. 5 is the side schematic view of two screw rods of the present invention pitch curve when making pure rolling.

Embodiment

Below in conjunction with accompanying drawing embodiment invention is described in further detail.

The structure shape of screw rod is referring to Fig. 1 and Fig. 2, curve abcde in this tooth-shaped screw bolt is the tooth curve on the screw rod radial cross section, a, e are on top circle, c, d are on root circle, curve ae is the circular arc of top circle, curve cd is the circular arc of root circle, form for two sections by prolate involute ab and superior trochoid bc between top circle camber line ae 1 end a point and root circle camber line cd 1 end c point, form by superior trochoid ed between top circle camber line ae the other end e point and root circle camber line cd the other end d point, number n 〉=1 of screw rod, the length of screw rod is greater than the length of two pitch.

Referring to Fig. 3, when the pitch circle II of screw rod 7 when the pitch circle I of screw rod 6 makes pure rolling, on the screw rod 7 with screw rod 6 in the track of e point corresponding points e ' be superior trochoid ed, and be superior trochoid bc with the track of a point corresponding points a ' in the screw rod 6, the curve shape of superior trochoid bc and ed is identical, direction is opposite, and it is as follows that each section tooth curve forms former mode:

(1) formation of superior trochoid ed:

x＝Rsin2ψ-2rsinψ

y＝rcos2ψ-Rcos2ψ $\mathrm{\&rho;}=\sqrt{x^2+y^2}$ $\mathrm{\&beta;}=\arccos \frac{{\mathrm{\&rho;}}^2+4r^2-R^2}{4\mathrm{r\&rho;}}$ $\mathrm{\&psi;}=\arccos \frac{4r^2+r^2-{\mathrm{\&rho;}}^2}{4\mathrm{Rr}}$

In φ=β-ψ formula: the right angled coordinates of any point on x, the y-flank profil

The polar radius vector and the corner of any point on p, the φ-flank profil

R, R ₀, r-top circle, root circle and Pitch radius

ψ-pitch circle II is with respect to the corner of pitch circle I

The angle of β-utmost point footpath and the two screw rods line of centres

(2) formation of superior trochoid bc:

x＝-Rsin(2ψ-φ _α)+2rsin(2ψ-φ _α)

y＝-Rcos(2ψ-φ _α)+2rcos(2ψ-φ _α)

φ＝ψ-β ${\mathrm{\&phi;}}_{\mathrm{\&alpha;}}=\mathrm{\&pi;}-\frac{1}{2}[{\cos }^{-1}\frac{{\mathrm{ob}}^2+{4r}^2-R^2}{4r\&CenterDot;\mathrm{ob}}-{\cos }^{-1}\frac{{4r}^2+R^2-{\mathrm{ob}}^2}{4\mathrm{Rr}}+\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{R}\right)$ $-{\cos }^{-1}\frac{R_0}{R}-\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{\mathrm{ob}}\right)+\mathrm{co}{s}^{-1}\frac{R_0}{\mathrm{ob}}]$ $\mathrm{ob}=\sqrt{R_0^2+{(2\sqrt{r^2-R_0^2}-\sqrt{R^2-R_0^2})}^2}$

In the formula: φ _αThe polar angle at-prolate involute ab and top circle intersection point a place

The utmost point footpath at ob-b place

(3) formation of top circle ae: $R=\sqrt{x^2+y^2}$

(4) formation of root circle cd: $R_0=\sqrt{x^2+y^2}$

(5) formation of prolate involute ab: $\mathrm{\&rho;}=\frac{R_0}{\cos \mathrm{\&alpha;}\cos \mathrm{\&gamma;}}$ ${\mathrm{\&phi;}}_{\mathrm{\&alpha;}}+\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{R}\right)-{\cos }^{-1}\frac{R_0}{R}-\mathrm{\&phi;}=\mathrm{tg\&alpha;}-\mathrm{\&alpha;}$ $({\mathrm{\&phi;}}_{\mathrm{\&alpha;}}\&le;\mathrm{\&phi;}<{\mathrm{\&phi;}}_{\mathrm{\&alpha;}}+\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{R}\right){-\cos }^{-1}\frac{R_0}{R}$

In the formula: the pressure angle of α-prolate involute ab

The helix angle of the helicoid of γ-screw rod

In fact the intersection point b of superior trochoid bc and prolate involute ab is exactly the starting point of two screw rods prolate involute engagement, as given tip circle radius R and Root radius R ₀, just can determine the utmost point footpath ob that b is ordered, by the character of prolate involute and superior trochoid, the angle of curve abc in polar coordinates, promptly ∠ aoc just can try to achieve, according to the requirement of engagement, the radian of the round arc cd of tip circle circular arc ea and root must equate that therefore, the tooth curve abcde among Fig. 1 is unique.

The meshing relation of two screw rods correspondence is: the pitch curve that screw rod 7 top circle a ' e ' are corresponding is the root circle cd of screw rod 6, point a ' is corresponding to superior trochoid bc, prolate involute a ' b ' is corresponding to prolate involute ab, root circle c ' d ' is corresponding to top circle ae, and some e ' is corresponding to superior trochoid ed.Otherwise,, some a is corresponding to superior trochoid b ' c ', and root circle cd is corresponding to top circle a ' e ', and some e is corresponding to superior trochoid e ' d '.

Referring to Fig. 4 and Fig. 5, when two screw rods rolled relatively, screw rod 7 will form space pitch curve 1-2-3-4-5 on screw rod 6, and wherein 3-4 is the straight line that parallels to the axis, 1-2 is actually the helical gear pitch curve of a pair of prolate involute, and 2-3 and 4-5 all are that radius is the helix of R.Equally, screw rod 6 also can form corresponding pitch curve on screw rod 7, is continuous owing to roll, and two pitch curves have been blocked the input cavity and the output cavity of pump, and constantly push ahead, thereby produces pressure fluid.

The formation of above-mentioned pair of meshing curve needs a pitch length, for input cavity and output cavity are isolated all the time, before the pair of meshing curve interrupts, must form another to pitch curve in the whole service process, therefore, the length of whole screw rod should be greater than two pitch.

The present invention is except the foregoing description, use present principles and also can be made into single-head screw or multiple thread screw,, can also have the form of gear engagement combination to form three screw rods and multi screwpump, as interior engagement, concurrent aces motion etc., make the pump of the numerous species that can satisfy different occasions uses.

Claims (3)

1. tooth-shaped screw bolt, curve abcde is the tooth curve on the screw rod radial cross section, a, e are on top circle, c, d are on root circle, and curve ae is the circular arc of top circle, and curve cd is the circular arc of root circle, it is characterized in that: described curve ab is a prolate involute, curve bc is a superior trochoid, and curve ed is a superior trochoid, and the length of described screw rod is greater than the length of two pitch.

2. tooth-shaped screw bolt according to claim 1 is characterized in that the curve shape of described superior trochoid bc, ed is identical, and direction is opposite.

3. according to the tooth-shaped screw bolt of claim 1 art, it is characterized in that the generation type of described each curve is as follows:

(1) formation of superior trochoid ed:

x＝Rsin2ψ-2rsinψ

y＝rcos2ψ-Rcos2ψ $\mathrm{\&rho;}=\sqrt{x^2+y^2}$ $\mathrm{\&beta;}=\arccos \frac{{\mathrm{\&rho;}}^2+{4r}^2-R^2}{4\mathrm{r\&rho;}}$ $\mathrm{\&psi;}=\arccos \frac{4r^2+r^2-{\mathrm{\&rho;}}^2}{4\mathrm{Rr}}$

φ＝β-ψ

In the formula: the right angled coordinates of any point on x, the y-flank profil

The polar radius vector and the corner of any point on p, the φ-flank profil

R, R ₀, r-top circle, root circle and Pitch radius

ψ-pitch circle II is with respect to the corner of pitch circle I

The angle of β-utmost point footpath and the two screw rods line of centres

(2) formation of superior trochoid bc:

x＝-Rsin(2ψ-φ _α)+2rsin(2ψ-φ _α)

y＝-Rcos(2ψ-φ _α)+2rcos(2ψ-φ _α)

φ＝ψ-β ${\mathrm{\&phi;}}_{\mathrm{\&alpha;}}=\mathrm{\&pi;}-\frac{1}{2}[{\cos }^{-1}\frac{{\mathrm{ob}}^2+4r^2-R^2}{4r\&CenterDot;\mathrm{ob}}-\mathrm{co}{s}^{-1}\frac{{4r}^2+R^2-o{b}^2}{4\mathrm{Rr}}+\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{R}\right)$ $-{\cos }^{-1}\frac{R_0}{R}-\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{\mathrm{ob}}\right)+c{\mathrm{os}}^{-1}\frac{R_0}{\mathrm{ob}}]$ $\mathrm{ob}=\sqrt{R_0^2+{(2\sqrt{r^2-R_0^2}-\sqrt{R^2-R_0^2})}^2}$

In the formula: φ _αThe polar angle at-prolate involute ab and top circle intersection point a place

The formation of utmost point footpath (3) the top circle ae at ob-b place: $R=\sqrt{x^2+y^2}$ (4) formation of root circle cd: $R_0=\sqrt{x^2+y^2}$ (5) formation of prolate involute ab: $\mathrm{\&rho;}=\frac{R_0}{\cos \mathrm{\&alpha;}\cos \mathrm{\&gamma;}}$ ${\mathrm{\&phi;}}_{\mathrm{\&alpha;}}+\mathrm{tg}\left({\cos }^{-1}\frac{R_0}{R}\right)-{\cos }^{-1}\frac{R_0}{R}-\mathrm{\&phi;}=\mathrm{tg\&alpha;}-\mathrm{\&alpha;}$ $({\mathrm{\&phi;}}_{\mathrm{\&alpha;}}\&le;\mathrm{\&phi;}<{\mathrm{\&phi;}}_{\mathrm{\&alpha;}}+\mathrm{tg}({\cos }^{-1}\frac{R_0}{R})-{\cos }^{-1}\frac{R_0}{R}$ In the formula: the pressure angle of α-prolate involute ab

The helix angle of the helicoid of γ-screw rod

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