CN217270815U - Screw rotor and screw vacuum pump - Google Patents

Abstract

An embodiment of the utility model provides a screw rotor and screw vacuum pump relates to the screw rotor field. The end face profile of the screw rotor comprises: a basic curve L, which comprises a cycloid AB, a root circle arc BC, an arc envelope line CD, an arc DE and an addendum circle arc EA which are connected in sequence, wherein the arc DE is a lobe crest circle arc, and the center O of the lobe crest circle ₂ And the center O of addendum circle ₁ A distance of b, center of circle O ₂ To the center of circle O ₁ The included angle of the extension line of the line connecting the straight line and the point A and the point B of the cycloid AB is w, the arc envelope line CD and the addendum circle arc EA are tangent to the arc DE, the arc envelope line CD and the cycloid AB are tangent to the dedendum circle arc BC, the arc envelope line CD is tangent to the dedendum circle without a sharp point, and the arc DE is tangent to the addendum circle without a sharp point.

Description

Screw rotor and screw vacuum pump

technical field

The utility model relates to the field of screw rotors, in particular to a screw rotor and a screw vacuum pump.

Background technique

A vacuum pump refers to a device or equipment that uses mechanical, physical, chemical or physical-chemical methods to evacuate the pumped container to obtain a vacuum. In layman's terms, a vacuum pump is a device that uses various methods to improve, generate and maintain vacuum in a closed space. According to the working principle of vacuum pump, vacuum pump can be basically divided into two types, namely gas capture pump and gas transmission pump. It is widely used in metallurgy, chemical industry, food, electronic coating and other industries. Commonly used vacuum pumps include dry screw vacuum pumps, water ring pumps, reciprocating pumps, slide valve pumps, rotary vane pumps, Roots pumps and diffusion pumps.

In the prior art, since the end face profile of the screw rotor has a sharp point, after the screw rotor meshes, the air tightness is not good during the working process, which affects the ultimate vacuum degree and pumping speed of the screw vacuum pump.

Utility model content

The utility model provides a screw rotor and a screw vacuum pump, which can prevent the screw rotor from meshing, and the air tightness is not good during the working process, which affects the ultimate vacuum degree and pumping speed of the screw vacuum pump.

Embodiments of the present utility model can be implemented as follows:

The embodiment of the present utility model provides a screw rotor, and the end face profile of the screw rotor includes:

a basic curve L, the basic curve L includes a cycloid AB, a tooth root circular arc BC, a circular arc envelope CD, a circular arc DE and a tooth top circular arc EA connected in sequence;

The parametric equation of the cycloid AB is:

X1=Rm*sin(2*t)-2A*sin(t)

Y1=2A*cos(t)-Rm*cos(2*t), where X1 and Y1 are the Cartesian coordinates of the points on the cycloid AB, Rm is the radius of the addendum circle, and A is the end face of the two meshing screw rotors Half of the center distance of the rotor profile, t is the preset parameter value;

The circular arc DE is a leaf peak circle arc, the distance between the center _O2 of the leaf peak circle and the center O1 _of the addendum circle is b, and the sum _of the straight line from the center _O2 to the center O1 is b. The included angle of the extension line connecting the point A and the point B of the cycloid AB is w, and the value range of the included angle w is: [90°, 180°];

The parametric equation of the arc envelope CD is:

X2=2*A*cos(t)-b*cos(2*t)-(r+δ)*(A*cos(t)+b*cos(2*t))/((A^2+ b^2+2*A*b*cos(t))^(1/2))

Y2=2*A*sin(t)-b*sin(2*t)+(r+δ)*(b*sin(2*t)-A*sin(t))/((A^2- b^2+2*A*b*cos(t))^(1/2)),

Among them, b+r=Rm, b=(Rm^2-a^2)/(2*(r+Rm*cos(π/2z))), X2 and Y2 are points on the arc envelope CD Cartesian coordinates, r is the radius of the blade peak circle, δ is the screw rotor clearance;

Both the circular arc envelope CD and the tooth tip circular arc EA are tangent to the circular arc DE, and the circular arc envelope CD and the cycloid AB are both tangent to the tooth root circular arc. BC are tangent.

Optionally, in the parametric equation of the cycloid AB, the value range of t is [0, arccos(2A/(2*Rm))].

Optionally, in the parameter equation of the arc envelope CD, the value range of t is [0, pi/(2*z)], and the parameter z is a design coefficient.

Optionally, the number of the basic curves L is two, and the two basic curves L are connected end to end in sequence.

Optionally, the number of the basic curves L is three, and the three basic curves L are connected in sequence from end to end.

Optionally, the number of the basic curves L is four, and the four basic curves L are connected in sequence from end to end.

Optionally, the number of the basic curves L is five, and the five basic curves L are connected end to end in sequence.

Optionally, the value of z is 5.

Optionally, the value of z is 4.

The embodiment of the present utility model also provides a screw vacuum pump, comprising a pump body and the above-mentioned screw rotor, and the two screw rotors are meshed with each other;

The point A of one of the screw rotors, the root circular arc BC and the arc envelope CD are respectively used to engage the cycloid AB and the root circular arc of the other screw rotor. Arc EA and said circular arc DE.

The beneficial effects of the screw rotor and the screw vacuum pump of the embodiment of the present invention include, for example:

The embodiment of the present invention provides a screw rotor, and the end face profile of the screw rotor includes: a basic curve L, and the basic curve L includes a cycloid AB, a tooth root circular arc BC, a circular arc envelope CD, The arc DE and the addendum arc EA, the arc DE is the leaf peak circular arc, the distance between the center _{O2 of} the leaf peak circle and the center O1 _of the addendum circle is b, and the straight line from the center O2 to the center O1 is b. The included angle of the extension line connecting point A and point B of the cycloid AB is w, the arc envelope CD and the addendum arc EA are both tangent to the arc DE, and the arc envelope CD and the cycloid AB is tangent to the tooth root circle arc BC, the arc envelope CD is tangent to the tooth root circle and has no sharp point, the arc DE is tangent to the tooth tip circle and has no sharp point, and the end face profiles are all smooth transitions, which can After the screw rotor is meshed, the air tightness is not good during the working process, which affects the ultimate vacuum degree and pumping speed of the screw vacuum pump.

The embodiment of the present utility model also provides a screw vacuum pump, which includes a pump body and the above-mentioned screw rotor. CD is used to mesh the cycloid AB, tooth root arc EA and arc DE of the other screw rotor respectively, which can avoid the air tightness of the screw rotor after meshing, which will affect the performance of the screw vacuum pump. Ultimate vacuum and pumping speed.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings that need to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention. Therefore, it should not be regarded as a limitation of the scope. For those of ordinary skill in the art, other related drawings can also be obtained from these drawings without any creative effort.

Fig. 1 is the schematic diagram of the end face profile of the single-end screw rotor provided in the embodiment of the present utility model;

2 is a schematic diagram of the end face profile meshing of a single-start screw rotor provided in an embodiment of the present utility model;

3 is a schematic diagram of the end face profile meshing of a double-ended screw rotor provided in an embodiment of the present utility model;

4 is a schematic diagram of the end face profile meshing of a three-head screw rotor provided in an embodiment of the present utility model;

5 is a schematic diagram of the end face profile meshing of a four-head screw rotor provided in an embodiment of the present utility model;

FIG. 6 is a schematic diagram of the end face profile meshing of the five-start screw rotor provided in the embodiment of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. The embodiments described above are a part of the embodiments of the present invention, but not all of the embodiments. The components of the embodiments of the invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

It should be noted that the features in the embodiments of the present invention may be combined with each other under the condition of no conflict.

A vacuum pump refers to a device or equipment that uses mechanical, physical, chemical or physical-chemical methods to evacuate the pumped container to obtain a vacuum. In layman's terms, a vacuum pump is a device that uses various methods to improve, generate and maintain vacuum in a closed space. According to the working principle of vacuum pump, vacuum pump can be basically divided into two types, namely gas capture pump and gas transmission pump. It is widely used in metallurgy, chemical industry, food, electronic coating and other industries. Commonly used vacuum pumps include dry screw vacuum pumps, water ring pumps, reciprocating pumps, slide valve pumps, rotary vane pumps, Roots pumps and diffusion pumps. In the prior art, since the end face profile of the screw rotor has a sharp point, after the screw rotor meshes, the air tightness is not good during the working process, which affects the ultimate vacuum degree and pumping speed of the screw vacuum pump.

In view of this, the screw rotor and the screw vacuum pump provided in the embodiments of the present invention can solve this problem.

Please refer to FIG. 1 to FIG. 6 , this embodiment provides a screw rotor and a screw vacuum pump, which will be described in detail next.

Please refer to FIG. 1 and FIG. 2 first, an embodiment of the present invention provides a screw vacuum pump, specifically a twin-screw vacuum pump, which includes a pump body and a screw rotor. The screw rotor is a single-head screw rotor, and the two screw rotors are mutually For meshing, the point A, the root arc BC and the arc envelope CD of one screw rotor are respectively used to mesh the cycloid AB, the root arc EA and the arc DE of the other screw rotor.

Specifically, the point A on the end face profile of the single-start screw rotor, the tooth root circular arc BC and the circular arc envelope CD are respectively used to engage the cycloid AB, Root circular arc EA and circular arc DE.

The end face profile of the screw rotor includes a basic curve L, and the basic curve L includes a cycloid AB, a root circular arc BC, a circular arc envelope CD, a circular arc DE, and a tooth top circular arc EA, which are sequentially connected. And the cycloid AB, the tooth root circular arc BC, the circular arc envelope CD, the circular arc DE and the addendum circular arc EA are connected end to end in sequence to form the end face profile of the single-head screw rotor. The arc DE is the leaf peak circle arc, the distance between the center O ₂ of the leaf peak circle and the center O ₁ of the tooth tip circle is b, and the line from the center 02 to the center O ₁ and the point A and point B of the cycloid AB are connected The included angle of the extension line is w, the arc envelope CD and the addendum arc EA are both tangent to the arc DE, and the arc envelope CD and the cycloid AB are both tangent to the root arc BC .

Therefore, the arc envelope CD is tangent to the root circle and has no sharp point, and the arc DE is tangent to the tooth tip circle and has no sharp point, which avoids the tool jumping and poor transition during the machining process of the screw rotor. , It can also prevent the screw rotor from meshing, and the air tightness is not good during the working process, which affects the ultimate vacuum degree and pumping speed of the screw vacuum pump.

Among them, the parametric equation of cycloid AB is:

X1=Rm*sin(2*t)-2A*sin(t)

Y1=2A*cos(t)-Rm*cos(2*t), where X1 and Y1 are the Cartesian coordinates of the points on the cycloid AB, Rm is the radius of the addendum circle, and A is the end face of the two meshing screw rotors Half of the center distance of the rotor profile, that is, the radius of the pitch circle with radius Ra, t is the preset parameter value.

Among them, the arc DE is the circular arc of the leaf peak, the radius of the leaf peak circle is r, the distance between the center _{O2 of} the leaf peak circle and the center O1 _of the addendum circle is b, the straight line from the center _O2 to the center O1 and the pendulum The included angle of the extension line connecting the point A and the point B of the line AB is w, and the value range of the included angle w is: [90°, 180°]. The value is 135°. In addition, the center 02 is located in the end face rotor profile of the single-start screw rotor.

In addition, the parametric equation of the arc envelope CD is:

X2=2*A*cos(t)-b*cos(2*t)-(r+δ)*(A*cos(t)+b*cos(2*t))/((A^2+ b^2+2*A*b*cos(t))^(1/2))

Y2=2*A*sin(t)-b*sin(2*t)+(r+δ)*(b*sin(2*t)-A*sin(t))/((A^2- b^2+2*A*b*cos(t))^(1/2)),

Wherein, in this embodiment, b+r=Rm, b=(Rm^2-a^2)/(2*(r+Rm*cos(π/2z))), X2 and Y2 are arc packets The Cartesian coordinate of the point on the curve CD, r is the radius of the blade peak circle, δ is the screw rotor gap, that is, δ is the meshing gap between the end face profiles of the two screw rotors, for example, δ can be 0.1mm-0.2mm.

In this example, in the parametric equation of the cycloid AB, the value range of t is [0, arccos(2A/(2*Rm))], and in the parametric equation of the arc envelope CD, the value range of t is [0, pi/(2*z)], the parameter z is the design coefficient, the value of z can be 2, 3, 4, 5, and the value of z can be selected according to the specific situation, when the value of z is larger When , the area utilization factor of the end face profile of the screw rotor will be larger.

Meanwhile, in this embodiment, the end face profiles of the two screw rotors meshing with each other are the same, which can be driven by a synchronous gear.

Please continue to refer to Figure 3 to Figure 6. The number of basic curves L can also be other numbers to form a multi-screw rotor, which can solve the dynamic balance problem existing in a single-screw rotor and reduce vibration. For example, the number of basic curves L is two , the two basic curves L are connected end to end to form a double-ended screw rotor, the number of basic curves L is three, and the three basic curves L are connected end to end to form a three-ended screw rotor, the number of basic curves L is four, and the four basic curves L The ends are connected in turn to form a four-head screw rotor, the number of basic curves L is five, and the five basic curves L are connected end-to-end to form a five-head screw rotor.

To sum up, the end face profile of the screw rotor includes: a basic curve L, and the basic curve L includes a cycloid AB, a root arc BC, a circular arc envelope CD, a circular arc DE, and a tooth tip circle connected in sequence. The arc EA, the arc DE are the leaf peak circular arc, the distance between the center O ₂ of the leaf peak circle and the center O ₁ of the addendum circle is b, the line from the center O ₂ to the center O ₁ and the point A of the cycloid AB The included angle of the extension line connecting the point B is w, the arc envelope CD and the addendum arc EA are both tangent to the arc DE, and the arc envelope CD and the cycloid AB are both connected to the root circle. The arc BC is tangent, the arc envelope CD is tangent to the root circle, and there is no sharp point, and the arc DE is tangent to the addendum circle and has no sharp point, which can prevent the screw rotor from meshing. The air tightness is not good, which affects the ultimate vacuum degree and pumping speed of the screw vacuum pump.

At the same time, the screw rotor reduces the area of the leaking triangle, reduces the inter-stage backflow of the pump, and when producing the screw rotor, the detection method can be through the common three-axis three-coordinate equipped with a stylus joint to detect the concave tooth surface and the helical tooth surface. The inspection reduces the difficulty of inspection.

The screw vacuum pump includes a pump body and the above-mentioned screw rotors. The two screw rotors are meshed with each other. The point A, the root arc BC and the arc envelope CD of one screw rotor are respectively used to mesh the pendulum of the other screw rotor. Line AB, tooth root arc EA and arc DE, which can prevent the screw rotor from meshing, and the air tightness is not good during the working process, which affects the ultimate vacuum degree and pumping speed of the screw vacuum pump.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field of the present invention can easily think of changes within the technical scope disclosed by the present invention. Or replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1. A screw rotor, characterized in that the end profile of the screw rotor comprises: a basic curve L, the basic curve L includes a cycloid AB, a tooth root circular arc BC, a circular arc envelope CD, a circular arc DE and a tooth top circular arc EA connected in sequence; The parametric equation of the cycloid AB is:

Among them, X1 and Y1 are the Cartesian coordinates of the point on the cycloid AB, Rm is the radius of the addendum circle, A is half of the center distance of the end face rotor profiles of the two meshing screw rotors, and t is the preset parameter value; The arc DE is a leaf peak circular arc, the straight line from the center _O2 of the leaf peak circle to the center O1 _of the addendum circle and the extension line connecting the point A and the point B of the cycloid AB The included angle is w, and the value range of the included angle w is: [90°, 180°]; The parametric equation of the arc envelope CD is:

Among them, X2 and Y2 are the Cartesian coordinates of the points on the arc envelope CD, r is the radius of the blade peak circle, δ is the screw rotor clearance, and b is the center O of the _blade peak circle and the center of the addendum circle. The distance of O ₁ , b+r=Rm, b=(Rm^2-a^2)/(2*(r+Rm*cos(π/2z))); Both the circular arc envelope CD and the tooth tip circular arc EA are tangent to the circular arc DE, and the circular arc envelope CD and the cycloid AB are both tangent to the tooth root circular arc. BC are tangent. 2 . The screw rotor according to claim 1 , wherein, in the parametric equation of the cycloid AB, the value range of t is [0, arccos(2A/(2*Rm))]. 3 . 3. The screw rotor according to claim 1, wherein, in the parameter equation of the arc envelope CD, the value range of t is [0, pi/(2*z)], and the parameter z is design factor. 4 . The screw rotor according to claim 3 , wherein the value of z is 5. 5 . 5 . The screw rotor according to claim 3 , wherein the value of z is 4. 6 . 6 . The screw rotor according to claim 1 , wherein the number of the basic curves L is four, and the four basic curves L are connected end to end in sequence. 7 . 7 . The screw rotor according to claim 1 , wherein the number of the basic curves L is five, and the five basic curves L are connected end to end in sequence. 8 . 8 . The screw rotor according to claim 1 , wherein the number of the basic curves L is two, and the two basic curves L are connected end to end in sequence. 9 . 9 . The screw rotor according to claim 1 , wherein the number of the basic curves L is three, and the three basic curves L are connected end to end in sequence. 10 . 10. A screw vacuum pump, characterized in that it comprises a pump body and two screw rotors according to any one of claims 1-9, and the two screw rotors mesh with each other; The point A of one of the screw rotors, the root circular arc BC and the arc envelope CD are respectively used to engage the cycloid AB and the root circular arc of the other screw rotor. Arc EA and said circular arc DE.

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