CN1546864A - Dentiform screw with short seal line - Google Patents

Abstract

The invention discloses a kind of short sealing wire tooth screw. The tooth top round curve is an arc line, the reverse side of the tooth round curve is an arc, one end of the tooth top ring arc and the one end of the tooth root ring are combined with prolonged line; another end of the tooth root ring arc and the tooth top ring arc are made up of arc, the evolvent and another arc, the length of screw axial tooth is bigger than the length of the two intervals. Only needs a screw interval there can form a sealing cavity, the structure is compact, the efficiency is high, the noise is small.

Description

A kind of screw rod of lacking the potted line profile of tooth

Affiliated technical field

The present invention relates to the screw rod of two screw pump, relate in particular to a kind of screw rod of lacking the potted line profile of tooth.

Background technique

The profile of tooth of existing two screw pump screw rod has cycloidal tooth profile, spiral of Archimedes profile of tooth, arc toothed and involute profile etc., though these profiles of tooth can both realize sealing fully, its length of sealing line is long, to such an extent as to influence the overall performance of pump, as efficient, pressure etc.

Summary of the invention

The purpose of this invention is to provide and to realize sealing fully, a kind of screw rod of lacking the potted line profile of tooth that length of sealing line is short again.

In order to achieve the above object, the technical solution used in the present invention is as follows: the shape of its screw rod radial cross section, the top circle curve is a circular arc line, and the root circle curve of the opposite side of top circle is a circular arc line, is made up of superior trochoid between top circle camber line one end points and root circle camber line one end points; Successively by circular arc line, involute and another circular arc line are formed between another end points of root circle camber line and another end points of top circle camber line, and the length of screw axial profile of tooth is greater than the length of two pitch.

The advantage that the present invention has is:

1) only need a pitch can have Seal cage of one's own, compact structure, rigidity improves;

2) because potted line is shorter, so good seal performance, delivery pressure is big, the efficient height, noise is little;

3) the present invention not only can be used for single-head screw, also can be used for double end and multiple thread screw, to form three screw rods and multi screwpump.

Description of drawings

The invention will be further described below in conjunction with drawings and Examples.

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

Fig. 2 is a longitudinal section view of the present invention;

Fig. 3 is two screw rods engagement figure when making pure rolling;

Fig. 4 is two screw rods pitch curve figure when making pure rolling;

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

Embodiment

As shown in Figure 1 and Figure 2, the shape of screw rod radial cross section of the present invention, the top circle curve is circular arc line af, and the root circle curve of the opposite side of top circle is circular arc line bc, is made up of superior trochoid ab between top circle camber line af 1 end a point and root circle camber line bc 1 end b point; Successively by circular arc line cd, involute de and another circular arc line ef form between root circle camber line bc the other end c point and the top circle camber line af the other end f point, and the length of screw axial profile of tooth is greater than the length of two pitch.Number n 〉=1 of screw rod.

The mode that each section tooth curve forms is as follows:

1) formation of superior trochoid ab:

x＝Rsin2ψ-2R ₀sinψ

y＝2R ₀cosψ-Rcos2ψ

$\mathrm{\&rho;}=\sqrt{x^2+{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="A20031010940100082.png"\; state="\{\{state\}\}">y</figure-callout>}}^2}$

$\mathrm{\&beta;}=\arccos \frac{{\mathrm{\&rho;}}^2+{{4\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="A20031010940100072.png"\; state="\{\{state\}\}">R</figure-callout>}}_0}^2-{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A20031010940100082.png"\; state="\{\{state\}\}">R</figure-callout>}}^2}{4{\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="A20031010940100072.png"\; state="\{\{state\}\}">R</figure-callout>}}_0\mathrm{\&rho;}}$

$\mathrm{\&psi;}=\arccos \frac{{{4\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="A20031010940100072.png"\; state="\{\{state\}\}">R</figure-callout>}}_0}^2+R^2-{\mathrm{\&rho;}}^2}{{4R}_{0}R}$

＝β-ψ

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

ρ, ---the polar radius vector and the corner of any point on the flank profil

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

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

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

2) formation of top circle camber line af:

ρ＝R

3) formation of root circle camber line bc:

ρ＝r

4) formation of circular arc line cd:

x ²+(y-R ₀) ²＝(R ₀-r) ²

5) formation of involute de:

${\mathrm{tg}\cos }^{-1}\frac{\mathrm{<figure-callout\; id="2"\; label="r\; r"\; filenames="A20031010940100082.png"\; state="\{\{state\}\}">r</figure-callout>}}{\sqrt{r^{}}}-{\cos }^{-1}\frac{\mathrm{<figure-callout\; id="2"\; label="r\; r"\; filenames="A20031010940100082.png"\; state="\{\{state\}\}">r</figure-callout>}}{\sqrt{r^{}}}$

${-\mathrm{tg}\cos }^{-1}\frac{\mathrm{<figure-callout\; id="2"\; label="r\; r"\; filenames="A20031010940100082.png"\; state="\{\{state\}\}">r</figure-callout>}}{\sqrt{r^{}}}+{\cos }^{-1}\frac{\mathrm{<figure-callout\; id="2"\; label="r\; r"\; filenames="A20031010940100082.png"\; state="\{\{state\}\}">r</figure-callout>}}{\sqrt{r^{}}}$

In the formula: α---the pressure angle of involute de

6) formation of circular arc line ef:

(x+R ₀sinθ) ²+(y-R ₀cosθ) ²＝(R ₀-r) ²

γ＝γ′。

The meshing relation of two screw rods correspondence is as shown in Figure 3:

The pitch curve of screw rod II top circle af correspondence is the root circle bc of screw rod I, screw rod II point a is corresponding to the superior trochoid ab of screw rod I, screw rod II root circle bc is corresponding to the top circle af of screw rod I, screw rod II involute de is corresponding to the involute ed of screw rod I, screw rod II circular arc ef is corresponding to the circular arc cd of screw rod I, vice versa.

When two screw rods rolled relatively, screw rod II will form space pitch curve 1-2-3-4-5-6 on screw rod I, as Fig. 4, shown in Figure 5.

Equally, screw rod I also can form corresponding pitch curve on screw rod II.Because it is continuous rotating, two pitch curves have been blocked the input cavity and the output cavity of pump, and constantly push ahead, thereby produce pressure fluid.

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

Claims (2)

1. screw rod of lacking the potted line profile of tooth, it is characterized in that: the shape of its screw rod radial cross section, the top circle curve is circular arc line (af), the root circle curve of the opposite side of top circle is circular arc line (bc), is made up of superior trochoid (ab) between top circle camber line (af) end (a) point and root circle camber line (bc) end (b) point; Successively by circular arc line (cd), involute (de) and another circular arc line (ef) are formed between root circle camber line (bc) the other end (c) point and top circle camber line (af) the other end (f) point, and the length of screw axial profile of tooth is greater than the length of two pitch.

2. a kind of screw rod of lacking the potted line profile of tooth according to claim 1 is characterized in that: the mode that each section tooth curve forms is as follows:

1) formation of superior trochoid (ab):

x＝Rsin2ψ-2R ₀sinψ

y＝2R ₀cosψ-Rcos2ψ

$\mathrm{\&rho;}=\sqrt{x^2+y^2}$

$\mathrm{\&beta;}=\arccos \frac{{\mathrm{\&rho;}}^2+{{4R}_0}^2-R^2}{{4R}_0\mathrm{\&rho;}}$

$\mathrm{\&psi;}=\mathrm{arccso}\frac{{{4R}_0}^2+R^2-{\mathrm{\&rho;}}^2}{{4R}_{0}R}$

＝β-ψ

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

ρ, ---the polar radius vector and the corner of any point on the flank profil

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

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

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

2) formation of top circle camber line (af):

ρ＝R

3) formation of root circle camber line (bc):

ρ＝r

4) formation of circular arc line (cd):

x ²+(y-R ₀) ²＝(R ₀-r) ²

5) formation of involute (de):

${\mathrm{tg}\cos }^{-1}\frac{r}{\sqrt{r^2+{(\sqrt{{R_0}^2-r^2}+R_0-r)}^2}}-{\cos }^{-1}\frac{r}{\sqrt{r^2+{(\sqrt{{R_0}^2-r^2}+R_0-r)}^2}}$

$-\mathrm{tg}\mathrm{co}{s}^{-1}\frac{r}{\sqrt{r^2+{(\sqrt{{R_0}^2-r^2}-R_0+r)}^2}}+{\cos }^{-1}\frac{r}{\sqrt{r^2+{(\sqrt{{R_0}^2-r^2}-R_0+r)}^2}}$

In the formula: α---the pressure angle of involute de

6) formation of circular arc line (ef):

(x+R ₀sinθ) ²+(y-R ₀cosθ) ²＝(R ₀-r) ²

γ＝γ′。

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