CN105697373A - Screw of screw vacuum pump - Google Patents

Abstract

The invention provides a screw of a screw vacuum pump, belongs to the technical field of vacuum pumps, and solves the problem that the machine heating time of a conventional screw vacuum pump is too long. The screw of the screw vacuum pump comprises a cylindrical screw body, wherein a spiral groove is formed in the outer side surface of the screw body; and the turn number of the spiral groove in a curved surface transition part is 0.04 to 0.375. According to the screw of the screw vacuum pump, a plurality of tests prove that compared with the prior art, a vacuum pump adopting the varying pitch screw has the advantage that the machine heating time can be shortened by at least 40% or above; and an air suction part and an air exhaust part are connected through the curved surface transition part, so that the spiral groove in the air suction part and the spiral groove in the air exhaust part are smoothly transited, the screw can be manufactured more easily, the running stability of the vacuum pump is effectively guaranteed, the length of a compression transition part is greatly shortened, the length of the screw can be shortened under the condition that the total spiral turn of the screw is not decreased, and the size of the vacuum pump is further decreased.

Description

A kind of screw rod of screw vacuum pump

Technical field

The invention belongs to vacuum pump technology field, relate to a kind of screw vacuum pump, the particularly screw rod of a kind of screw vacuum pump。

Background technology

Screw vacuum pump has the advantage such as maintenance period length and convenience, environmental protection, highly reliable, high efficiency and easy manipulation, thus refers and synthesizes in a lot of techniques, and screw vacuum pump replacement water ring vacuum pump, sliding valve vacuum pump, other wet vacuum pump become inexorable trend。

Applicant is it is proposed that a kind of dry screw vacuum pump varying pitch screw, and it is documented in Chinese patent literature (application publication number: CN102937094A), the vacuum pump adopting this screw rod provides the optimum selection of energy requirement, noise, internal operating temperature, structure space and manufacturing expense with vacuum pump before relatively, also has the advantage that application is relatively broad。In actual production, client thinks that the warm-up times of above-mentioned vacuum pump is long, affects production efficiency, and then it is intended that can shorten warm-up times。

Summary of the invention

The present invention proposes the screw rod of a kind of screw vacuum pump, and the technical problem to be solved in the present invention is how to shorten the warm-up times of screw vacuum pump。

Solving the technical problem that of the present invention can be realized by following technical proposal:

The screw rod of this screw vacuum pump, including the cylindrical body of rod, the lateral surface of the body of rod has a helicla flute, spiral fluted two-port lays respectively in the both ends of the surface of the body of rod, the one end of the body of rod is suction unit, and the other end is exhaust portion, and in suction unit, spiral fluted pitch is constant, in exhaust portion, spiral fluted pitch is constant, and in exhaust portion, spiral fluted pitch is less than spiral fluted pitch in suction unit；There is between suction unit and exhaust portion surface blending portion；In surface blending portion, helicla flute one end connects with helicla flute in suction unit, and the other end connects with helicla flute in exhaust portion, and in surface blending portion, helicla flute passes through, and pitch is non-linear gradual to be reduced；In surface blending portion, the spiral fluted number of turns is 0.04～0.375 circle。

It is connected by the surface blending portion of relatively minor spiral angle between suction unit and the exhaust portion of the screw rod of this screw vacuum pump；Shorten passage of heat length significantly；And then it is effectively shortened warm-up times。

The screw rod of this screw vacuum pump is integral type structure, adopts metal forging pole to process, it is to avoid the problems such as what the screw rod that casting processes existed cause the material uneven, porose and loose。Also avoid split manufacture simultaneously and cause manufacture difficulty and assembly difficulty height, precision to be difficult to ensure the problems such as card and gap difficulty control。

In the screw rod of above-mentioned screw vacuum pump, in described surface blending portion, helicla flute looping curve non-linear change tendencies meets following formula:

$f\left(t\right)={\mathrm{cpt}}_1+t_2\[cp\left(\frac{t}{t_2}-\frac{t_1}{t_2}\right)-\frac{\left(c-1\right)p{\left(\frac{t}{t_2}-\frac{t_1}{t_2}\right)}^3}{2}+\frac{\left(c-1\right)p{\left(\frac{t}{t_2}-\frac{t_1}{t_2}\right)}^3\left(\frac{t}{t_2}-\frac{t_1}{t_2}-1\right)}{2}\],t_1\≤t\≤t_1+t_2;$

Wherein: t is that on the body of rod, spiral fluted is wound around the number of turns；T₁For the spiral fluted number of turns in suction unit；T₂For the spiral fluted number of turns in surface blending portion；C is the reduced overall ratio of dry screw vacuum pump；p₁For spiral fluted pitch on intake section；P is spiral fluted pitch in exhaust portion。

In the screw rod of above-mentioned screw vacuum pump, in described surface blending portion, helicla flute pitch non-linear change tendencies meets following formula:

$\begin{array}{c}{f}^{\′}\left(t\right)=cp-\frac{3\left(c-1\right)p{\left(\frac{t}{t_2}-\frac{t_1}{t_2}\right)}^3}{2}+\frac{3\left(c-1\right)p{\left(\frac{t}{t_2}-\frac{t_1}{t_2}\right)}^2\left(\frac{t}{t_2}-\frac{t_1}{t_2}-1\right)}{2}+\frac{\left(c-1\right)p{\left(\frac{t}{t_2}-\frac{t_1}{t_2}\right)}^3}{2},\\ t_1\≤t\≤t_1+t_2;\end{array}$

Wherein: t is that on the body of rod, spiral fluted is wound around the number of turns；T₁For the spiral fluted number of turns in suction unit；T₂For the spiral fluted number of turns in surface blending portion；C is the reduced overall ratio of dry screw vacuum pump；p₁For spiral fluted pitch on intake section；P is spiral fluted pitch in exhaust portion。

In surface blending portion, in helicla flute looping curve non-linear change tendencies and surface blending portion, helicla flute pitch non-linear change tendencies also can adopt following proposal to replace: in described surface blending portion, helicla flute looping curve non-linear change tendencies meets following formula:

$f\left(t\right)={\mathrm{cpt}}_1+\frac{c+1}{2}p(t-t_1)+\frac{t_2}{\mathrm{\π}}\frac{(c-1)p}{2}sin(\frac{\mathrm{\π}}{t_2}t-\frac{{\mathrm{\πt}}_1}{t_2}),t_1\≤t\≤t_1+t_2;$

Wherein: t is that on the body of rod, spiral fluted is wound around the number of turns；T₁For the spiral fluted number of turns in suction unit；T₂For the spiral fluted number of turns in surface blending portion；C is the reduced overall ratio of dry screw vacuum pump；p₁For spiral fluted pitch on intake section；P is spiral fluted pitch in exhaust portion。

In above-mentioned dry screw vacuum pump varying pitch screw, in described surface blending portion, helicla flute pitch non-linear change tendencies meets following formula:

$f^{\′}\left(t\right)=\frac{c+1}{2}p+\frac{(c-1)p}{2}cos(\frac{\mathrm{\π}}{t_2}t-\frac{{\mathrm{\πt}}_1}{t_2}),t_1\≤t\≤t_1+t_2;$

Wherein: t is that on the body of rod, spiral fluted is wound around the number of turns；T₁For the spiral fluted number of turns in suction unit；T₂For the spiral fluted number of turns in surface blending portion；C is the reduced overall ratio of dry screw vacuum pump；p₁For spiral fluted pitch on intake section；P is spiral fluted pitch in exhaust portion。

In the screw rod of above-mentioned screw vacuum pump, on the described body of rod, spiral fluted spiral number of total coils encloses be more than or equal to 5, and in suction unit, spiral fluted is wound around the number of turns is 1～3 circle。

The vacuum pump adopting this varying pitch screw confirms compared with prior art at least to shorten warm-up times more than 40% by substantial amounts of test。

It is connected by surface blending portion between suction unit and exhaust portion, makes the helicla flute in suction unit and the helicla flute gentle transition in exhaust portion, screw rod can be made to be more easily manufactured, effectively ensure again the stability that vacuum pump runs。Shorten the length in surface blending portion simultaneously significantly, in the situation not reducing screw spiral number of total coils, the length of screw rod can be shortened, and then vacuum pump volume can be made less。

Accompanying drawing explanation

Fig. 1 is the structural representation of the screw rod of this screw vacuum pump。

Fig. 2 is the axial location of the screw rod of this screw vacuum pump and the relationship change schematic diagram being wound around the number of turns。

Fig. 3 is the pitch of the screw rod of this screw vacuum pump and the relationship change schematic diagram being wound around the number of turns。

In figure, 1, the body of rod；2, helicla flute；3, suction unit；4, surface blending portion；5, exhaust portion。

Detailed description of the invention

The following is specific embodiments of the invention and in conjunction with accompanying drawing, technical scheme is further described, but the present invention is not limited to these embodiments。

As shown in Figure 1, the screw rod of this screw vacuum pump includes the cylindrical body of rod 1, the lateral surface of the body of rod 1 has a helicla flute 2, the two-port of helicla flute 2 lays respectively in the both ends of the surface of the body of rod 1, the one end of the body of rod 1 is suction unit 3, and the other end is exhaust portion 5, and in suction unit 3, the pitch of helicla flute 2 is constant, in exhaust portion 5, the pitch of helicla flute 2 is constant, and in exhaust portion 5, the pitch of helicla flute 2 is less than the pitch of helicla flute 2 in suction unit 3；There is between suction unit 3 and exhaust portion 5 surface blending portion 4；In surface blending portion 4, helicla flute 2 one end connects with helicla flute 2 in suction unit 3, and the other end connects with helicla flute 2 in exhaust portion 5, and in surface blending portion 4, helicla flute 2 passes through, and pitch is non-linear gradual to be reduced。

The screw rod of this screw vacuum pump is integral type structure, adopts metal forging pole to process。

On the body of rod 1, spiral fluted spiral number of total coils is 5 circles, and in suction unit 3, the winding number of turns of helicla flute 2 is 1 circle；In surface blending portion 4, the number of turns of helicla flute 2 is 0.04 circle；In exhaust portion 5, the winding number of turns of helicla flute 2 is 3.96 circles。

W in Fig. 2 represents the length of screw rod, and t represents the winding number of turns of helicla flute 2 on the body of rod 1。In surface blending portion 4, helicla flute 2 looping curve non-linear change tendencies meets following formula:

$\begin{array}{c}f\left(t\right)=cp+0.04\×\[cp\left(25t-25\right)-\frac{\left(c-1\right)p{\left(25t-25\right)}^3}{2}+\frac{\left(c-1\right)p{\left(25t-25\right)}^3\left(25t-26\right)}{2}\],\\ 1\≤t\≤1.04;\end{array}$

Wherein: c is the reduced overall ratio of dry screw vacuum pump, namelyp₁Pitch for helicla flute on intake section 2；P is the pitch of helicla flute 2 in exhaust portion 5；As preferably 1.5≤c≤10。

As it is shown on figure 3, the w ' in Fig. 3 represents the pitch of helicla flute 2, t represents the winding number of turns of helicla flute 2 on the body of rod 1。In surface blending portion 4, helicla flute 2 pitch non-linear change tendencies meets following formula:

$\begin{array}{c}{f}^{\′}\left(t\right)=cp-\frac{3\left(c-1\right)p{\left(25t-25\right)}^2}{2}+\frac{3\left(c-1\right)p{\left(25t-25\right)}^2\left(25t-26\right)}{2}+\frac{\left(c-1\right)p{\left(25t-25\right)}^3}{2},\\ 1\≤t\≤1.04;\end{array}$

Wherein: c is the reduced overall ratio of dry screw vacuum pump, namelyp₁Pitch for helicla flute on intake section 2；P is the pitch of helicla flute 2 in exhaust portion 5。

Embodiment two

The present embodiment is essentially identical with structure and the principle of embodiment one, and different place is in that: on the body of rod 1, spiral fluted spiral number of total coils is 6 circles；In suction unit 3, the winding number of turns of helicla flute 2 is 1.5 circles；In surface blending portion 4, the number of turns of helicla flute 2 is 0.25 circle；In exhaust portion 5, the winding number of turns of helicla flute 2 is 4.25 circles。

In surface blending portion 4, helicla flute 2 looping curve non-linear change tendencies meets following formula:

$f\left(t\right)=1.5cp+0.25\×\[cp(4t-6)-\frac{(c-1)p{(4t-6)}^3}{2}+\frac{(c-1)p{(4t-6)}^3(4t-7)}{2}\],1.5\≤t\≤1.75;$

Wherein: t represents the winding number of turns of helicla flute 2 on the body of rod 1；C is the reduced overall ratio of screw vacuum pump, namelyp₁Pitch for helicla flute on intake section 2；P is the pitch of helicla flute 2 in exhaust portion 5。

In surface blending portion 4, helicla flute 2 pitch non-linear change tendencies meets following formula:

$f^{\′}\left(t\right)=cp-\frac{3\left(c-1\right)p{\left(4t-6\right)}^2}{2}+\frac{3\left(c-1\right)p{\left(4t-6\right)}^2\left(4t-7\right)}{2}+\frac{\left(c-1\right)p{\left(4t-6\right)}^3}{2},1.5\≤t\≤1.75;$

Wherein: t represents the winding number of turns of helicla flute 2 on the body of rod 1；C is the reduced overall ratio of screw vacuum pump, namelyp₁Pitch for helicla flute on intake section 2；P is the pitch of helicla flute 2 in exhaust portion 5。

Embodiment three

The present embodiment is essentially identical with structure and the principle of embodiment one, and different place is in that: on the body of rod 1, spiral fluted spiral number of total coils is 7 circles；In suction unit 3, the winding number of turns of helicla flute 2 is 2 circles。In surface blending portion 4, the number of turns of helicla flute 2 is 0.375 circle。In exhaust portion 5, the winding number of turns of helicla flute 2 is 4.625 circles。

In surface blending portion 4, helicla flute 2 looping curve non-linear change tendencies meets following formula:

$\begin{array}{c}f\left(t\right)=2cp+0.375\×\[cp\left(\frac{t-2}{0.375}\right)-\frac{(c-1)p{\left(\frac{t-2}{0.375}\right)}^3}{2}+\frac{(c-1)p{\left(\frac{t-2}{0.375}\right)}^3(\frac{t-2}{0.375}-1)}{2}\],\\ 2\≤t\≤2.375;\end{array}$

Wherein: t represents the winding number of turns of helicla flute 2 on the body of rod 1；C is the reduced overall ratio of screw vacuum pump, namelyp₁Pitch for helicla flute on intake section 2；P is the pitch of helicla flute 2 in exhaust portion 5。

In surface blending portion 4, helicla flute 2 pitch non-linear change tendencies meets following formula:

$f^{\′}\left(t\right)=cp-\frac{3(c-1)p{\left(\frac{t-2}{0.375}\right)}^2}{2}+\frac{3(c-1)p{\left(\frac{t-2}{0.375}\right)}^2(\frac{t-2}{0.375}-1)}{2}+\frac{(c-1)p{\left(\frac{t-2}{0.375}\right)}^3}{2},$

Wherein: t represents the winding number of turns of helicla flute 2 on the body of rod 1；C is the reduced overall ratio of screw vacuum pump, namelyp₁Pitch for helicla flute on intake section 2；P is the pitch of helicla flute 2 in exhaust portion 5。

Embodiment four

The present embodiment is essentially identical with structure and the principle of embodiment three, and different place is in that: in surface blending portion 4, helicla flute 2 looping curve non-linear change tendencies meets following formula:

$f\left(t\right)=2cp+\frac{c+1}{2}p(t-2)+0.375\frac{(c-1)p}{2}sin(\frac{\mathrm{\π}}{0.375}t-\frac{2\mathrm{\π}}{0.375}),2\≤t\≤2.375;$

Wherein: t represents the winding number of turns of helicla flute 2 on the body of rod 1；C is the reduced overall ratio of screw vacuum pump；P is the pitch of helicla flute 2 in exhaust portion 5；

In surface blending portion 4, helicla flute 2 pitch non-linear change tendencies meets following formula:

$f^{\′}\left(t\right)=\frac{c+1}{2}p+\frac{(c-1)p}{2}cos(\frac{\mathrm{\π}}{0.375}t-\frac{2\mathrm{\π}}{0.375}),2\≤t\≤2.375;$

Wherein: t represents the winding number of turns of helicla flute 2 on the body of rod 1；C is the reduced overall ratio of screw vacuum pump, namelyp₁Pitch for helicla flute on intake section 2；P is the pitch of helicla flute 2 in exhaust portion 5。

Claims (4)

1. the screw rod of a screw vacuum pump, including the cylindrical body of rod (1), the lateral surface of the body of rod (1) has a helicla flute (2), the two-port of helicla flute (2) lays respectively in the both ends of the surface of the body of rod (1), the one end of the body of rod (1) is suction unit (3), the other end is exhaust portion (5), the pitch of the upper helicla flute (2) of suction unit (3) is constant, the pitch of the upper helicla flute (2) of exhaust portion (5) is constant, the pitch of the upper helicla flute (2) of exhaust portion (5) is less than the pitch of the upper helicla flute (2) of suction unit (3)；There is between suction unit (3) and exhaust portion (5) surface blending portion (4)；Upper helicla flute (2) one end, surface blending portion (4) connects with the upper helicla flute (2) of suction unit (3), the other end connects with the upper helicla flute (2) of exhaust portion (5), and surface blending portion (4) upper helicla flute (2) passes through, and pitch is non-linear gradual to be reduced；It is characterized in that, the number of turns of surface blending portion (4) upper helicla flute (2) is 0.04～0.375 circle；Upper helicla flute (2) the looping curve non-linear change tendencies of described surface blending portion (4) meets following formula:

$f\left(t\right)={\mathrm{cpt}}_1+\frac{c+1}{2}p(t-t_1)+\frac{t_2}{\mathrm{\π}}\frac{(c-1)p}{2}sin(\frac{\mathrm{\π}}{t_2}t-\frac{{\mathrm{\πt}}_1}{t_2}),t_1\≤t\≤t_1+t_2;$

Wherein: t is the winding number of turns of the upper helicla flute (2) of the body of rod (1)；T₁The number of turns for the upper helicla flute (2) of suction unit (3)；T₂The number of turns for surface blending portion (4) upper helicla flute (2)；C is the reduced overall ratio of dry screw vacuum pump；p₁Pitch for helicla flute on intake section (2)；P is the pitch of the upper helicla flute (2) of exhaust portion (5)。

2. the screw rod of screw vacuum pump according to claim 1, it is characterised in that the screw rod of this screw vacuum pump is integral type structure, adopts metal forging pole to process。

3. the screw rod of screw vacuum pump according to claim 1, it is characterised in that upper helicla flute (2) the pitch non-linear change tendencies of described surface blending portion (4) meets following formula:

$f^{\′}\left(t\right)=\frac{c+1}{2}p+\frac{(c-1)p}{2}cos(\frac{\mathrm{\π}}{t_2}t-\frac{{\mathrm{\πt}}_1}{t_2}),t_1\≤t\≤t_1+t_2;$

Wherein: t is the winding number of turns of the upper helicla flute (2) of the body of rod (1)；T₁The number of turns for the upper helicla flute (2) of suction unit (3)；T₂The number of turns for surface blending portion (4) upper helicla flute (2)；C is the reduced overall ratio of dry screw vacuum pump；p₁Pitch for helicla flute on intake section (2)；P is the pitch of the upper helicla flute (2) of exhaust portion (5)。

4. the screw rod of the screw vacuum pump according to any one in claims 1 to 3, it is characterized in that, the spiral number of total coils of the upper helicla flute (2) of the body of rod (1) encloses be more than or equal to 5, and the winding number of turns of the upper helicla flute (2) of suction unit (3) is 1～3 circle。