CN115898866A - Rotor profile for Roots blower and design method thereof - Google Patents
Rotor profile for Roots blower and design method thereof Download PDFInfo
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- CN115898866A CN115898866A CN202211684930.4A CN202211684930A CN115898866A CN 115898866 A CN115898866 A CN 115898866A CN 202211684930 A CN202211684930 A CN 202211684930A CN 115898866 A CN115898866 A CN 115898866A
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Abstract
The invention provides a rotor profile for a Roots blower and a design method thereof, and belongs to the technical field of rotor profiles. The invention relates to a rotor body consisting of blade peaks and blade valleys which are connected in sequence, wherein a molded line from the lowest point of any blade valley to the highest point of the adjacent blade peak consists of a pin tooth circular arc section AB, a straight line section BC, a curve section CD, a transition tangent section DE, a circular arc section EF, a chamfer angle section FG and a tooth top sealing line section GH which are connected smoothly in sequence; the transition tangent line segment DE is a transition tangent line of the curve segment CD and the circular arc segment EF. The invention has high area utilization coefficient, large element volume, high volume efficiency and high integral operation efficiency of the fan.
Description
Technical Field
The invention relates to the technical field of rotor profiles, in particular to a rotor profile for a Roots blower and a design method thereof.
Background
The Roots blower is a double-rotor positive displacement rotary blower, originally invented to convey air when an 8-shaped impeller water pump was maintained in 1854 by two brothers of Roots in the United states. Through a pair of intermeshing's rotor to opposite direction rotation, the impeller is gapped contactless with casing and both sides curb plate, also keeps certain clearance contactless through synchronous gear drive between two impellers simultaneously, and along with the rotation of impeller, the space that forms between impeller and the casing accomplishes the exhaust process of breathing in from the import to arranging the mouth, realizes gaseous transport. Because the structure is simple, the maintenance amount is small, the gas is forcedly transmitted, and because a gap is formed between the rotor and the shell, lubricating oil is not needed, the gas transmission device belongs to oil-free transmission, and is widely applied to various industries, such as petrochemical industry, cement, steel, food, sewage treatment, tap water and other material or gas transmission application fields. The roots blower is used to pump air according to the difference of gas suction inlet and pressure, inlet negative pressure or vacuum, and is conventionally called a roots vacuum pump at the moment, but the basic structure and the principle are the same. The most important part in the Roots blower is an impeller rotor, according to the historical development stage, the impeller rotor is firstly provided with two vanes, later three vanes or even four vanes appear, the three vanes are most widely applied at present, and the four vanes only have partial application in the mechanical supercharger because of no remarkable advantages. The profile of the rotor determines the running efficiency and noise of the Roots blower, and also determines the selection and production efficiency of a rotor machining process and a production machine tool, so that the design of the rotor profile becomes the key of the Roots blower design.
The existing molded line structure is generally in a pin tooth arc shape, an involute shape and a cycloid shape, the molded lines have different defects in terms of respective lateral weight, for example, a cycloid impeller has the advantages of smooth and low meshing noise, but the processing area is large, the production efficiency is low, the area utilization coefficient is small, the volumetric efficiency is low, the involute impeller area utilization coefficient is large, but the reduction of the impeller head leads to the increase of the width of an opening during exhaust, the backflow impact is large, the noise is high, the pin tooth arc impeller is located in the middle position compared with the pin tooth arc impeller and the pin tooth arc impeller, and the processing technology and the production efficiency are still not optimized.
Disclosure of Invention
In view of the above, in order to solve the above-mentioned deficiencies in the prior art, on the one hand, the present invention provides a rotor profile for a roots blower, wherein a profile from a lowest point of any one of the roots blower to a highest point of an adjacent tip thereof is composed of a pin tooth arc segment AB, a straight segment BC, a curved segment CD, a transition tangent segment DE, an arc segment EF, a chamfer segment FG and a tip sealing segment GH, which are smoothly connected in sequence, and the rotor profile has the advantages of high area utilization factor, large element volume, high volumetric efficiency and high overall blower operating efficiency.
In order to achieve the purpose, the invention provides the following technical scheme:
a rotor profile for a Roots blower comprises a rotor body consisting of blade peaks and blade valleys which are connected in sequence, wherein the profile from the lowest point of any one blade valley to the highest point of the adjacent blade peak consists of a pin tooth circular arc section AB, a straight line section BC, a curve section CD, a transition tangent section DE, a circular arc section EF, a chamfer angle section FG and a tooth crest sealing line section GH which are connected smoothly in sequence;
the transition tangent line section DE is a transition tangent line of the curve section CD and the circular arc section EF.
Preferably, the rotor body is a three-lobe rotor.
Preferably, the center distance between the two mutually meshed rotor bodies is the distance between the centers of the respective pitch circles, and the centers of the two pitch circles are O 1 And O 2 Center to center distance O 1 O 2 And (= 2 a), the diameter DW =2a 2 x Z/(2 x Z) =2a of the pitch circle, wherein DW is the diameter of the pitch circle, 2a is the center distance, and Z is the number of rotor teeth.
Preferably, the valley radius: r1=0.5a + e, peak leaf radius: r2=0.5a-e, where e = (0 to 0.02) a, a is half of the center-to-center distance.
Preferably, a line O connecting the chamfer line segment FG and the centers of the two pitch circles 1 O 2 The chamfer angle between the two is 10-45 degrees.
Preferably, the width of the tooth top sealing line segment GH is (0.02-0.05) a/2.
On the other hand, the invention provides a design method of the rotor profile for the Roots blower, which comprises the following steps:
pin tooth arc segment AB: the circle center I of the leaf valley is on the pitch circle of the rotor body, and the circle centers of two pitch circles of the two mutually meshed rotor bodies are O respectively 1 And O 2， ∠IO 1 O 2 At 60 deg., the radius r1 of the valley is used as the arc, and the point A intersects IO 1 On the connection line, B point and the line segment BC jointly determine;
straight line segment BC: passing through center of circle O 1 Extending a straight line to the pitch circle, intersecting at the C point of the pitch circle, and connecting the straight line with the centers of the two pitch circles 1 O 2 The included angle is 30 degrees, and the intersection point of the straight line and the leaf valley circular arc is B;
curve segment CD: forming an envelope CD by coordinate transposition for a conjugate curve of another three-bladed rotor meshed with the three-bladed rotor relative to a line segment BC;
arc section EF: drawing an arc by taking a node P on a pitch circle as the center of a circle and r2 as the radius, drawing a tangent of the arc by a point D, wherein the tangent point is E, and a point F is determined by a chamfer line segment FG and a tooth top sealing line segment GH;
tooth tip seal line segment GH: with O 1 As the center of circle, R is the radius of a circular arc, and the point H is the connecting line O between the circular arc and the centers of two circles 1 O 2 The intersection point of (2) is obtained by the width specification of the tooth top sealing line, wherein R is the distance from the center of a pitch circle to the highest point of a leaf peak;
chamfer line segment FG: the attack chamfer angle is shown from the point G, and the chamfer line intersects with the leaf peak radius arc at the point F.
The rotor profile for the Roots blower provided by the invention has the advantages that the profile from the lowest point of any one blade valley to the highest point of the adjacent blade peak consists of a pin tooth circular arc section AB, a straight line section BC, a curve section CD, a transition tangent section DE, a circular arc section EF, a chamfer angle section FG and a tooth top sealing line section GH which are smoothly connected in sequence, and the rotor profile in the shape has the following beneficial effects:
1) The area utilization coefficient is high, the element volume is large, the volume efficiency is high, and the overall operation efficiency of the fan is high;
2) The rotor has symmetrical geometric shape, high linear speed allowable value, stable operation, small abrupt change of the opening width of the discharge port, small impact and low noise of the backflow pulse, and the flow rate can be improved by increasing the rotating speed;
3) The sealing performance is good, continuous meshing is realized, leakage is less, and the volume efficiency is high;
4) The structure is simple, the production and the manufacture are facilitated, the processing precision is high, and the production efficiency is improved;
5) The fan has enough strength to realize large pressure difference on the premise of meeting the maximum area utilization coefficient, and the capacity of the fan is improved.
Drawings
FIG. 1 is a schematic view of a rotor profile structure;
in the figure, O 1 、O 2 The center of each pitch circle is the center of each pitch circle, DW is the diameter of each pitch circle, R is the distance between the center of each pitch circle and the highest point of each leaf peak, R1 is the radius of each leaf valley, and R2 is the radius of each leaf peak.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
The invention uses the three-blade rotor shown in figure 1 as an example to illustrate the structure of the profile, the profiles of the two rotors are completely consistent, the three impellers in the rotors are uniformly distributed, each impeller is respectively symmetrical to the central axis, for the convenience of description, the AH section of 1/6 part of one rotor is used for illustration, and the configuration of the 1/6 part can adopt the mirror image rear array to acquire the end surface profile of the whole rotor. The AH segment comprises 7 segments of lines, including circular arcs, straight lines, envelope lines and the like, to form the most basic line.
As shown in fig. 1, the rotor profile for a roots blower provided by the invention comprises a rotor body consisting of blade peaks and blade valleys which are connected in sequence, wherein the profile from the lowest point of any blade valley to the highest point of the blade peak adjacent to the blade valley consists of a pin tooth circular arc section AB, a straight line section BC, a curve section CD, a transition tangent section DE, a circular arc section EF, a chamfer angle section FG and a tooth top sealing line section GH which are connected smoothly in sequence;
the transition tangent line section DE is the transition tangent line of the curve section CD and the circular arc section EF.
In the invention, the rotor body is a three-blade rotor.
In the invention, the rotor profile takes the following values:
in the invention, the center distance of the two mutually meshed rotor bodies is the distance between the centers of respective pitch circles, and the centers of the two pitch circles are O respectively 1 And O 2 Center to center distance O 1 O 2 And (= 2 a), the diameter DW =2a 2 x Z/(2 x Z) =2a of the pitch circle, wherein DW is the diameter of the pitch circle, 2a is the center distance, and Z is the number of rotor teeth.
In the present invention, the valley radius: r1=0.5a + e, peak leaf radius: r2=0.5a-e, where e = (0 to 0.02) a, a is half the center-to-center distance (radius of pitch circle).
In the invention, the chamfer line segment FG is connected with two pitch circlesLine O connecting the centers of circles 1 O 2 The chamfer angle between the two is 10-45 degrees.
In the present invention, the tooth top seal line segment GH has a width of (0.02 to 0.05) a/2.
In the present invention, the radial to radial ratio R/a =1.5.
In the rotor profile for the Roots blower provided by the invention,
the pin tooth circular arc section AB is simple and regular;
straight line segment BC is simple and regular and is convenient to process;
a curved segment CD, which forms a mesh with BC throughout the rotation on the other rotor, maintaining the sealing characteristics;
arc section EF, simple rule, convenient processing simultaneously because the meshing characteristic of round pin tooth circular arc is whole cambered surface meshing simultaneously in the twinkling of an eye, the sealed of rotor is realized by D point in the twinkling of an eye at this moreover, consequently does not need whole cambered surface all finish machining, can be less than the addendum circular arc with this face, only does rough machining, reduces the area of finish machining, improves production efficiency and does not influence the operating efficiency.
The tooth top sealing line segment GH has the function of forming sealing with the shell cylinder body to form a small-area sealing line instead of the whole pin tooth circular arc tooth top sealing, and has the advantages that the Roots blower is subjected to short-time overload deformation bending or high-temperature expansion rotor and cylinder body contact friction in the running process, and the rotor returns to continue running as large loss cannot be caused due to friction not in a large area, and overload and overtemperature disappear.
On the other hand, the invention provides a design method of the rotor profile for the Roots blower, which comprises the following steps:
pin tooth arc segment AB: the circle center I of the leaf valley is on the pitch circle of the rotor body, and the circle centers of two pitch circles of the two mutually meshed rotor bodies are O respectively 1 And O 2， ∠IO 1 O 2 At 60 deg., the radius r1 of the valley is used as the arc, and the point A intersects IO 1 On the connecting line, B point and line segment BC are jointly determined;
straight line segment BC: through the center of circle O 1 Extending a straight line to the pitch circle, intersecting at the C point of the pitch circle, and forming a straight lineLine O connecting the centers of two circles 1 O 2 The included angle of the straight line is 30 degrees, and the intersection point of the straight line and the leaf valley circular arc is B;
curve segment CD: forming an envelope CD by coordinate transposition for a conjugate curve of another three-bladed rotor meshed with the three-bladed rotor relative to a line segment BC;
arc segment EF: drawing an arc by taking a node P on a pitch circle as the center of a circle and r2 as the radius, drawing a tangent of the arc by a point D, wherein the tangent point is E, and a point F is determined by a chamfer line segment FG and a tooth top sealing line segment GH;
tooth crest sealing line segment GH: with O 1 As the center of circle, R is the radius of the arc, and H is the connecting line O between the arc and the centers of the two circles 1 O 2 The intersection point of (2) is defined by the width of the tooth top sealing line to obtain a G point, wherein R is the distance from the center of a pitch circle to the highest point of a blade peak;
chamfer line segment FG: the attack chamfer angle is shown from the point G, and the chamfer line intersects with the leaf peak radius arc at the point F.
The rotor profile and the method for manufacturing the same have the outstanding advantages that the area utilization coefficient is improved, the area utilization coefficient can reach 0.53 according to calculation, the maximum area utilization coefficient is 2% higher than that of the traditional involute profile of 0.5185 under the condition of the same radial distance ratio of 1.5, the volumetric efficiency is improved, the integral operation efficiency is improved, and the radial distance ratio of 1.5 ensures that the rotor has enough strength to realize large pressure difference and improve the operation capacity of a fan. In addition, only BC and CD are finish machining surfaces on the premise of ensuring the sealing performance, so that the finish machining area is reduced, the production efficiency is improved, and meanwhile, because only CD sections in the machining surfaces are irregular surfaces, a high-precision machine tool is needed, the selection of the machine tool is facilitated, the use of the finish machining machine tool is reduced, and the cost is reduced. The EF line segment designed for reducing the finish machining surface forms a GH tooth top sealing line at the same time, thereby reducing the failure rate and ensuring the safe operation of equipment.
The above-described embodiments are merely illustrative and not restrictive of the present invention, and variations, modifications and the like of the above-described embodiments may fall within the scope of the claims of the present invention as long as they fall within the spirit and scope of the present invention.
Claims (7)
1. A rotor profile for a Roots blower is a rotor body consisting of blade peaks and blade valleys which are connected in sequence, and is characterized in that the profile from the lowest point of any blade valley to the highest point of the adjacent blade peak consists of a pin tooth circular arc section AB, a straight line section BC, a curve section CD, a transition tangent section DE, a circular arc section EF, a chamfer angle section FG and a tooth crest sealing line section GH which are connected smoothly in sequence;
the transition tangent line section DE is the transition tangent line of the curve section CD and the circular arc section EF.
2. The rotor profile for a roots blower of claim 1 wherein the rotor body is a tri-lobe rotor.
3. The rotor profile for a roots blower as claimed in claim 1, wherein the center distance between the two intermeshing rotor bodies is the distance between the centers of the respective pitch circles, the centers of the two pitch circles being O 1 And O 2 Center to center distance O 1 O 2 And (= 2 a), the diameter DW =2a 2 x Z/(2 x Z) =2a of the pitch circle, wherein DW is the diameter of the pitch circle, 2a is the center distance, and Z is the number of rotor teeth.
4. A rotor profile for a roots blower as claimed in claim 3 wherein the ratio of the lobe radius: r1=0.5a + e, peak leaf radius: r2=0.5a-e, where e = (0 to 0.02) a, a is half of the center-to-center distance.
5. The rotor profile for a Roots blower as claimed in claim 1, wherein the chamfer line segment FG is connected to a line O connecting the centers of two circles 1 O 2 The chamfer angle between the two is 10-45 degrees.
6. The rotor profile for a roots blower as claimed in claim 1, wherein the tooth tip sealing line segment GH has a width of (0.02-0.05) a/2.
7. The design method for rotor profiles of roots blowers according to any one of claims 1-6, characterized by comprising the steps of:
pin tooth arc segment AB: the circle center I of each leaf valley is on the pitch circle of the rotor body, and the circle centers of two pitch circles of the two mutually meshed rotor bodies are O respectively 1 And O 2， ∠IO 1 O 2 At 60 deg., the radius r1 of the valley is used as the arc, and the point A intersects IO 1 On the connecting line, B point and line segment BC are jointly determined;
straight line segment BC: through the center of circle O 1 Extending a straight line to the pitch circle, intersecting at the C point of the pitch circle, and connecting the straight line with the centers of the two pitch circles 1 O 2 The included angle of the straight line is 30 degrees, and the intersection point of the straight line and the leaf valley circular arc is B;
curve segment CD: forming an envelope line CD by coordinate transposition for a conjugate curve of the other three-bladed rotor meshed with the three-bladed rotor relative to a line segment BC;
arc segment EF: drawing an arc by taking a node P on a pitch circle as a circle center and r2 as a radius, taking a point D as a tangent of the arc, taking a tangent point as E, and determining a point F by a chamfer line segment FG and a tooth top sealing line segment GH;
tooth crest sealing line segment GH: with O 1 As the center of circle, R is the radius of the arc, and H is the connecting line O between the arc and the centers of the two circles 1 O 2 The intersection point of (2) is defined by the width of the tooth top sealing line to obtain a G point, wherein R is the distance from the center of a pitch circle to the highest point of a blade peak;
chamfer line segment FG: the attack chamfer angle is shown from the point G, and the chamfer line intersects with the leaf peak radius arc at the point F.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211684930.4A CN115898866A (en) | 2022-12-27 | 2022-12-27 | Rotor profile for Roots blower and design method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211684930.4A CN115898866A (en) | 2022-12-27 | 2022-12-27 | Rotor profile for Roots blower and design method thereof |
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| CN115898866A true CN115898866A (en) | 2023-04-04 |
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| CN202211684930.4A Pending CN115898866A (en) | 2022-12-27 | 2022-12-27 | Rotor profile for Roots blower and design method thereof |
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