阅读说明：本技术 一种螺杆真空泵转子及螺杆真空泵 (Screw vacuum pump rotor and screw vacuum pump ) 是由 丁小川 刘永强 丁辉 徐晓明 于 2021-11-02 设计创作，主要内容包括：本发明涉及一种螺杆真空泵转子及螺杆真空泵。本发明的螺杆真空泵转子由端面型线绕螺旋线旋转扫描加工而成,其特点在于：所述螺杆真空泵转子的端面型线的形状和螺旋线的螺距均随着转子长度L的变化而发生变化；所述端面型线由4段型线组成,包括渐开线AB、齿顶圆BC、摆线CD、以及齿根圆DA；所述端面型线的形状和参数,全部由转子中心距a和齿根圆DA的半径RF计算得到。本发明的结构设计合理,内容积调节能力大,运行稳定,降低转子动平衡调节难度。(The invention relates to a screw vacuum pump rotor and a screw vacuum pump. The screw vacuum pump rotor is formed by end surface profile wire winding spiral line rotary scanning processing, and is characterized in that: the shape of the end face molded line of the screw vacuum pump rotor and the pitch of the spiral line are changed along with the change of the length L of the rotor; the end face molded line consists of 4 sections of molded lines and comprises an involute AB, an addendum circle BC, a cycloid CD and a dedendum circle DA; the shape and the parameters of the end face molded line are all obtained by calculating the center distance a of the rotor and the radius RF of the tooth root circle DA. The rotor dynamic balance adjusting device is reasonable in structural design, large in inner volume adjusting capacity, stable in operation and capable of reducing the difficulty of rotor dynamic balance adjustment.)

1. The utility model provides a screw vacuum pump rotor, is formed by terminal surface type line around the rotatory scanning processing of helix, its characterized in that: the shape of the end face molded line of the screw vacuum pump rotor and the pitch of the spiral line are changed along with the change of the length L of the rotor; the end face molded line consists of 4 sections of molded lines and comprises an involute AB, an addendum circle BC, a cycloid CD and a dedendum circle DA; the shape and the parameters of the end face molded line are all obtained by calculating the center distance a of the rotor and the radius RF of the tooth root circle DA; the rotor center distance a is a determined value and is determined according to the size of the vacuum pump;

the radius RF of the root circle DA linearly changes with the length L of the rotor, the radius RF of the rotor intake end face is RF1, and the equation is given by the following equation at different z-coordinate positions (intake end face z =0, exhaust end face z = L) from the rotor intake end face to the exhaust end face with a predetermined curvature β:

RF=RF1+β*z

the coordinate equation of the involute AB is as follows:

Rb=RF-T

X=Rb*cos(t1)+Rb* t1*sin(t1)

Y=Rb*sin(t1)-Rb*t1*cos(t1)

in the formula: t is a constant, and T1 is a generating circle angle from the point A to the point B of the involute;

the coordinate equation of the addendum circle BC is as follows:

X=(a-RF)*cos(t2)

Y=(a-RF)*sin(t2)

in the formula: t2 is the angle between the central line of the center and the point C from the addendum circle B;

the coordinate equation of the cycloid CD is:

X=a*sin(t3)-(a-RF)*cos(π/2-2*t3)

Y=-a*cos(t3)+(a-RF)*sin(π/2-2*t3)

in the formula: t3 is the central line angle between the cycloidal point C and the cycloidal point D relative to the circle center, and pi is 3.1415927;

the coordinate equation of the root circle DA is as follows:

X=RF*cos(t4)

Y=RF*sin(t4)

in the formula: t4 is the angle between the addendum circle D and the center line of point A relative to the center;

the screw pitch P of the rotor helical line changes nonlinearly from the air suction end surface to the air discharge end surface of the rotor, the problem of unbalance caused by asymmetric end surface molded lines of the rotor can be reduced as much as possible, and the screw pitch equation is as follows:

P=PA*cos(t)+PB

in the formula: PA and PB are constants, respectively, and t is the angle of rotation of the spiral.

2. A screw vacuum pump rotor as claimed in claim 1, wherein: from the rotor suction end face to the rotor exhaust end face, the diameter of the addendum circle of the rotor is linearly reduced, and the diameter of the dedendum circle of the rotor is linearly increased.

3. A screw vacuum pump rotor as claimed in claim 1, wherein: the rotor pitch varies with the rotor length or is a specific constant value.

4. A screw vacuum pump rotor as claimed in claim 1, wherein: the value of the rotor center distance a is 50-300mm, and the value of the rotor center distance a increases with the increase of the corresponding vacuum pump.

5. A screw vacuum pump, its characterized in that: a rotor for a screw vacuum pump as claimed in any one of claims 1 to 4.

Technical Field

The invention relates to a screw vacuum pump rotor and a screw vacuum pump, belonging to parts of a fluid pressure system.

Background

The screw vacuum pump is widely applied to production processes of industries such as chips, lithium batteries and photovoltaic power generation, can be used as a part in a fluid pressure system, and is important equipment in related process procedures. With the continuous development of intelligent equipment technology and computer numerical computation technology, the technology of the special-shaped screw vacuum pump is rapidly growing. The existing screw vacuum pump mainly has the following problems:

firstly, the internal volume ratio (or internal pressure ratio) of the vacuum pump cannot be large, so that the problems of low vacuum pump efficiency, high exhaust temperature and the like occur when the vacuum pump runs at high vacuum degree;

in the traditional equal-diameter or equal-distance screw rotor, the volume change of the sucked gas is discontinuous in the compression process, the leakage rate of each section of the vacuum pump rotor is not uniform, and the internal temperature and pressure are not uniform, so that the operation fault is easily caused;

and thirdly, when the special-shaped screw rotor is processed, the dynamic balance adjustment difficulty of the rotor is high due to the end surface profile, and the processing process is complex, so that the processing efficiency and the cost of a product are influenced.

The main reason for causing the problems is that no screw vacuum pump rotor with reasonable structural design exists at present. Although there are some relatively good rotors of screw vacuum pumps, for example, chinese patent publication No. CN110645172A, whose publication date is 2020, 01/03/2020, discloses a rotor of screw vacuum pump and a screw vacuum pump; also, for example, in chinese patent publication No. CN109372746A, published as 2019, 22.02, a normal spiral screw rotor of a twin-screw vacuum pump is disclosed; as another example, chinese patent publication No. CN111980920A, whose publication date is 24/11/2020, discloses a screw rotor set and a vacuum pump having the screw rotor set; these screw vacuum pump rotors have not yet effectively solved the above-mentioned problems.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a screw vacuum pump rotor and a screw vacuum pump, which have the advantages of reasonable structural design, high internal volume adjusting capacity, stable operation and reduction of the difficulty in adjusting the dynamic balance of the rotor.

The technical scheme adopted by the invention for solving the problems is as follows: this screw vacuum pump rotor is formed by terminal surface type line winding helix rotation scanning processing, and its structural feature lies in: the shape of the end face molded line of the screw vacuum pump rotor and the pitch of the spiral line are changed along with the change of the length L of the rotor; the end face molded line consists of 4 sections of molded lines and comprises an involute AB, an addendum circle BC, a cycloid CD and a dedendum circle DA; the shape and the parameters of the end face molded line are all obtained by calculating the center distance a of the rotor and the radius RF of the tooth root circle DA; the rotor center distance a is a determined value and is determined according to the size of the vacuum pump;

the radius RF of the root circle DA linearly changes with the length L of the rotor, the radius RF of the rotor intake end face is RF1, and the equation is given by the following equation at different z-coordinate positions (intake end face z =0, exhaust end face z = L) from the rotor intake end face to the exhaust end face with a predetermined curvature β:

RF=RF1+β*z

the coordinate equation of the involute AB is as follows:

Rb=RF-T

X=Rb*cos(t1)+Rb* t1*sin(t1)

Y=Rb*sin(t1)-Rb*t1*cos(t1)

in the formula: t is a constant, and T1 is a generating circle angle from the point A to the point B of the involute;

the coordinate equation of the addendum circle BC is as follows:

X=(a-RF)*cos(t2)

Y=(a-RF)*sin(t2)

in the formula: t2 is the angle between the central line of the center and the point C from the addendum circle B;

the coordinate equation of the cycloid CD is:

X=a*sin(t3)-(a-RF)*cos(π/2-2*t3)

Y=-a*cos(t3)+(a-RF)*sin(π/2-2*t3)

in the formula: t3 is the central line angle between the cycloidal point C and the cycloidal point D relative to the circle center, and pi is 3.1415927;

the coordinate equation of the root circle DA is as follows:

X=RF*cos(t4)

Y=RF*sin(t4)

in the formula: t4 is the angle between the addendum circle D and the center line of point A relative to the center;

the screw pitch P of the rotor helical line changes nonlinearly from the air suction end surface to the air discharge end surface of the rotor, the problem of unbalance caused by asymmetric end surface molded lines of the rotor can be reduced as much as possible, and the screw pitch equation is as follows:

P=PA*cos(t)+PB

in the formula: PA and PB are constants, respectively, and t is the angle of rotation of the spiral.

Preferably, in the present invention, the diameter of the tip circle of the rotor decreases linearly and the diameter of the root circle of the rotor increases linearly from the suction end face to the discharge end face of the rotor.

Preferably, the rotor pitch of the present invention varies with the length of the rotor, or the rotor pitch is a specific constant value.

Preferably, the rotor center distance a is 50-300mm, and the value of the rotor center distance a increases with the increase of the corresponding vacuum pump. The larger the vacuum pump flow rate is, the larger the value of a is, and in view of the efficiency of rotor machining and cost control, a is preferably designed in the interval of 50-300 mm.

The utility model provides a screw vacuum pump which structural feature lies in: the screw vacuum pump rotor is provided.

Compared with the prior art, the invention has the following advantages and effects: the vacuum pump rotor adopts the variable diameter and variable pitch design, from the air suction end face of the rotor to the air exhaust end face, the section of the rotor is gradually reduced, the center distance of the rotor is kept unchanged, the diameter of a root circle is linearly increased, the corresponding linear reduction of an addendum circle is realized, and the vacuum pump rotor has larger inner volume adjusting capacity compared with a rotor with the same diameter or the same section; the screw pitch of the rotor changes from large to small from the air suction end surface to the air discharge end surface of the rotor, and the rotor has larger inner volume adjusting capacity compared with a rotor with the same screw pitch; the change of the rotor pitch meets the cosine function relationship, the pitch is symmetrical before and after air suction is finished, the unbalance amount of the rotor can be effectively reduced, and the difficulty in dynamic balance adjustment of the rotor is reduced.

Drawings

In order to more clearly illustrate the embodiments and/or technical solutions of the present invention, the drawings used in the description of the embodiments and/or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic view of the profile of a rotor of a screw vacuum pump according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.

Examples are given.

Referring to fig. 1, the rotor of the screw vacuum pump in the embodiment is formed by rotationally scanning an end-face profile around a spiral line, and both the shape of the end-face profile of the rotor of the screw vacuum pump and the pitch of the spiral line change along with the change of the length L of the rotor; the end face molded line consists of 4 sections of molded lines and comprises an involute AB, an addendum circle BC, a cycloid CD and a dedendum circle DA; the shape and parameters of the end face molded line are all obtained by calculating the center distance a of the rotor and the radius RF of the tooth root circle DA; the rotor center distance a is a determined value and is determined according to the size of the vacuum pump;

the radius RF of the root circle DA linearly changes with the length L of the rotor, the radius RF of the rotor intake end face is RF1, and the equation is given by the following equation at different z-coordinate positions (intake end face z =0, exhaust end face z = L) from the rotor intake end face to the exhaust end face with a predetermined curvature β:

RF=RF1+β*z

the coordinate equation of the involute AB is:

Rb=RF-T

X=Rb*cos(t1)+Rb* t1*sin(t1)

Y=Rb*sin(t1)-Rb*t1*cos(t1)

in the formula: t is a constant, and T1 is a generating circle angle from the point A to the point B of the involute;

the coordinate equation of the addendum circle BC is:

X=(a-RF)*cos(t2)

Y=(a-RF)*sin(t2)

in the formula: t2 is the angle between the central line of the center and the point C from the addendum circle B;

the coordinate equation for a cycloid CD is:

X=a*sin(t3)-(a-RF)*cos(π/2-2*t3)

Y=-a*cos(t3)+(a-RF)*sin(π/2-2*t3)

in the formula: t3 is the central line angle between the cycloidal point C and the cycloidal point D relative to the circle center, and pi is 3.1415927;

the coordinate equation of the root circle DA is:

X=RF*cos(t4)

Y=RF*sin(t4)

in the formula: t4 is the angle between the addendum circle D and the center line of point A relative to the center;

the rotor helix, its pitch P is the nonlinear change from rotor suction end face to exhaust end face, can reduce the unbalance problem that the asymmetric terminal surface molded lines of rotor caused as far as possible, and its pitch equation is:

P=PA*cos(t)+PB

in the formula: PA and PB are constants, respectively, and t is the angle of rotation of the spiral.

From the rotor suction end face to the rotor exhaust end face, the diameter of the addendum circle of the rotor is linearly reduced, and the diameter of the dedendum circle of the rotor is linearly increased.

The rotor pitch varies with the rotor length or is a specific constant value.

The value of the rotor center distance a is 50-300mm, and the value of the rotor center distance a increases with the increase of the corresponding vacuum pump.

The screw vacuum pump in the embodiment has the screw vacuum pump rotor.

The change of the rotor pitch meets the cosine function relationship, the pitch is symmetrical before and after air suction is finished, the unbalance amount of the rotor can be effectively reduced, and the difficulty in dynamic balance adjustment of the rotor is reduced.

In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an illustration of the structure of the present invention. Equivalent or simple changes in the structure, characteristics and principles of the invention are included in the protection scope of the patent. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.