Rotor design method for integrated general fluid machinery and general fluid module

Abstract

The present invention belongs to the technical field of rotor manufacturing, and particularly relates to a rotor design method for an integrated general fluid machine and a general fluid module. The rotor design method of the present invention includes the following steps: 1) Obtaining the increment of the electric drive length; 2) Obtaining the increment of the effective permanent magnet length; 3) Obtaining the axial length of the permanent magnet; 4) After obtaining the axial length of the permanent magnet in step 3) and the stator length in step 1), both ends of the permanent magnet are extended beyond the two ends of the stator, so as to obtain the extended lengths at both ends of the permanent magnet respectively. The present invention can ensure the uniform distribution of the air-gap magnetic field along the axial direction while ensuring the effective utilization rate of the electric drive winding, thereby ensuring or even improving the actual working efficiency of the rotor.

Description

Technical Field

[0001] The present invention belongs to the technical field of rotor manufacturing, and particularly relates to a rotor design method for an integrated general fluid machine and a general fluid module. Background Art

[0002] A general fluid machine refers to a machine that converts energy with a fluid (liquid or gas) as the working medium. According to the form of energy conversion, it can be divided into prime movers (such as water turbines, steam turbines, etc.) and working machines (such as pumps, compressors, etc.). The former converts the energy of the fluid into mechanical energy; the latter converts mechanical energy into the energy of the fluid, pressurizes the fluid and realizes industrial purposes such as transportation. It has the characteristics of a large variety and a large quantity, and is widely distributed in fields such as petrochemical industry, iron and steel metallurgy, flood control and drainage municipal engineering, and ship and military engineering. Its safe and reliable operation is closely related to people's lives. Generally speaking, the structure of a general fluid machine is composed of an electric motor, an intermediate connecting frame (such as a bracket, a bearing box, etc.), and fluid machine functional components (for a pump, it is a volute and blades; for a compressor, it is a screw / vortex blade and a housing; for a water turbine, it is a blade and a volute). Affected by cross-disciplines, the electric motor, the intermediate connecting frame, and the fluid machine functional components are separately manufactured, installed, and finally connected together. That is to say, the electric motor belongs to the electrical engineering discipline and is separately manufactured and processed; the fluid machine functional components belong to the fluid machine discipline and are also separately manufactured and processed. In order to connect the electric motor and the fluid machine functional components together and realize their functions, an intermediate connecting frame is required to connect the two, which will cause the overall structure of the entire general fluid machine to increase, increasing carbon emissions during the manufacturing process. In addition, due to the existence of the intermediate connecting frame, the frictional losses of components such as bearings and seals are increased, resulting in increased energy consumption during its operation. At the same time, the number of vulnerable components is increased, greatly reducing the service life of the general fluid machine. Especially in the field of hydraulic machinery, affected by the service life of mechanical seals, hydraulic machinery needs to be repaired every year, increasing the maintenance cost during use. In addition, the technical problems to be solved by the rotor currently also include: First, the utilization rate of effective electric drive of the current rotor is generally not high; Second, due to the existence of an edge magnetic field near the end face of the stator of the electric motor, the air-gap magnetic field is unevenly distributed axially, which is also likely to affect the actual working efficiency of the rotor; Third, how to optimize the rotor structure so that the final finished electric motor always has a constant axial magnetic thrust has always been the core issue of the optimized design of the rotor. Summary of the Invention

[0003] One of the objectives of the present invention is to provide a rotor design method for an integrated general fluid machinery, which can ensure the effective utilization rate of the electric drive winding while meeting the requirement of the uniformity of the axial distribution of the air-gap magnetic field, thereby ensuring or even improving the actual working efficiency of the rotor. Another objective of the present invention is to provide a general fluid module applying the rotor design method, so as to further improve the overall efficiency of the unit by means of integrated design, reducing the intermediate connecting frame, reducing the number of vulnerable parts and frictional losses.

[0004] To achieve the above objectives, the present invention adopts the following technical solutions:

[0005] A rotor design method for an integrated general fluid machinery, characterized by including the following steps:

[0006] 1), obtaining the electric drive length increment by the following formula

[0007]

[0008] Wherein:

[0009] is the effective electric drive length of the stator, obtained by classifying the turn-linked armature winding at the end flux into the effective air-gap flux;

[0010] L a is the stator length;

[0011] h m is the maximum radial thickness of the permanent magnet;

[0012] δ is the radial air-gap distance from the outer wall of the stator to the inner wall of the permanent magnet;

[0013] h in is the thickness of the spacer sleeve at the outer wall of the stator; when the general fluid machinery conveys gas, h in is zero; when the general fluid machinery conveys liquid, 0 < h in < 3 mm;

[0014] 2), obtaining the effective permanent magnet length increment by the following formula

[0015]

[0016] In the formula, A1, A2, A3 and A4 are coefficients respectively, and the values are as follows:

[0017]

[0018] 3), obtaining the axial length L of the permanent magnet by the following formula m :

[0019]

[0020] Wherein:

[0021] is the effective permanent magnet length and the effective electric drive length of the stator, which is obtained by incorporating the armature winding linked by the end flux into the effective air-gap flux, similar to the stator;

[0022] 4), from the axial length L of the permanent magnet in step 3) m and the stator length L in step 1) a , it can be known that L m > L a ;

[0023] At this time, both ends of the permanent magnet extend beyond the two ends of the stator, so as to obtain the extension lengths ΔL m1 and ΔL m2 at both ends of the permanent magnet respectively, and the two satisfy the following formula:

[0024]

[0025] Preferably, when the integrated general fluid machinery is a medium pump, the end of the permanent magnet where ΔL m2 is located is the end where the load is located.

[0026] Preferably, the two ends of the permanent magnet are of equal width; compared with the two ends of the permanent magnet, the two side edges of the permanent magnet are both trimmed structures and satisfy the following relational formula:

[0027]

[0028] Wherein:

[0029] α is the included angle formed by the side edge of the permanent magnet and the rotor axis;

[0030] β1 is the angle occupied by the starting position of trimming on the permanent magnet from the side edge in the rotor cross-section;

[0031] β2 is the angle occupied between the two side edges of the permanent magnet in the rotor cross-section;

[0032] Δh m = h m - Δh m1 where h m is the maximum radial thickness of the permanent magnet, and Δh m1 is the radial thickness from the starting position of trimming of the permanent magnet to the side edge;

[0033] R is the chamfer of the side edge of the permanent magnet.

[0034] Preferably, the permanent magnet is in the shape of a square plate or an arc-shaped tile.

[0035] Preferably, a general fluid module applying the rotor design method for an integrated general fluid machine is characterized in that: the general fluid module includes a stator and a rotor coaxially sleeved outside the stator, and blades or teeth are integrally fixed on the outer wall of the rotor; permanent magnets are sequentially and uniformly arranged around the axis of the rotor at the inner wall of the rotor, and there is a movable gap between the permanent magnets and an isolation sleeve coaxially fixed at the outer wall of the stator; on the cross-section of the rotor, a set of concave stage grooves are respectively arranged at the inner wall of the rotor where the two side edges of each permanent magnet are located, the stage grooves penetrate through the rotor and the groove length direction is parallel to the side edges of the permanent magnets;

[0036] The groove depth h z and the groove width b z of the stage grooves satisfy the following formula:

[0037]

[0038] The beneficial effects of the present invention are as follows:

[0039] 1), through the above solution, on the one hand, in order to make full use of effective materials, through the calculation of the steps of the present invention, it can be known that the axial length L m of the permanent magnet is greater than the length L a of the stator, thus realizing the maximum utilization of the electric drive winding in the stator region and avoiding the waste of materials. On the other hand, since there is an edge magnetic field near the end face of the stator, the air-gap magnetic field is unevenly distributed along the axial direction; in order to solve this problem, the present invention classifies the electric drive winding at the end flux into the effective air-gap flux, thereby introducing the effective electric drive length and the effective permanent magnet length, thus ensuring the uniformity requirement of the air-gap magnetic field along the axial direction and finally meeting the high working efficiency requirement of the rotor, with remarkable results.

[0040] 2), through the overall structure formed by the combination of the rotor and the stator, the stator and the rotor can be submerged in the fluid medium, and the fluid medium can effectively absorb most of the vibration and noise, greatly reducing the vibration and noise of the whole unit. In addition, the integrated design concept formed by the rotor and the stator also eliminates the matching process of the motor and the fluid machine, improves the matching degree between the electromechanical part and the fluid machine part, and overall improves the efficiency of the unit. The present invention can highly integrate the functions of the motor and the fluid machine, the load is on the rotor, no additional intermediate connecting frame is required, and the carbon emission is smaller; reducing the intermediate connecting frame also means the cancellation of supporting bearings, seals, etc., and the corresponding frictional losses are also lower, the energy consumption is lower, the structure is more compact and reasonable, and the overall efficiency of the unit is further improved. Description of the Drawings

[0041] Figure 1 is a schematic structural diagram of one embodiment of the present invention;

[0042] Figure 2 Schematic diagram of the cooperation state between the permanent magnet and the stator at the rotor of the present invention;

[0043] Figure 3 Assembly relationship diagram of the permanent magnet and the rotor;

[0044] Figure 4 Electromagnetic torque simulation comparison diagram between the rotor design method of the present invention and the traditional rotor structure;

[0045] Figure 5 Magnetic slot torque simulation comparison diagram between the rotor design method of the present invention and the traditional rotor structure.

[0046] The actual corresponding relationship between each label and the component name of the present invention is as follows:

[0047] 10 - Stator; 11 - Isolation sleeve; 20 - Rotor; 21 - Permanent magnet; 22 - Stage slot; 23 - Blade. Detailed implementation manner

[0048] For the convenience of understanding, here, taking an axial flow pump as an example, in combination with Figures 1-5 , the following further description is made on the specific structure and working mode of the present invention:

[0049] The specific structure of the present invention is as Figure 1 shown. Its structure mainly includes an external rotor 20 and a stator 10 located inside the rotor 20; the blade 23 is installed on the rotor 20, and corresponding diversion blades and guide blades are arranged at both ends of the flow channel, finally forming one of the implementation example structures of the general fluid module of the present invention. It can be seen from Figure 1 that since the blade 23 and the rotor 20 are integrated into one structure, when the rotor 20 rotates, the fluid continuously enters the rotor 20 and the stator 10 and flows out through the gaps of each fitting, which can greatly take away the heat generated during the operation of the rotor 20 and the stator 10 and improve the actual service life of the axial flow pump; by optimizing and transforming the rotor 20 in combination with the following rotor design method of the present invention, while ensuring the effective utilization rate of the electric drive winding, the uniformity requirement of the air-gap magnetic field distribution along the axial direction can be realized, thereby ensuring and even improving the actual working efficiency of the rotor 20 and even the entire general fluid module.

[0050] More specifically, a rotor design method for an integrated general fluid machine, characterized by comprising the following steps:

[0051] 1), Obtain the electric drive length increment by the following formula

[0052]

[0053] Wherein:

[0054] It is the effective electric drive length of the stator 10, obtained by including the turn-linked armature winding at the end flux into the effective air-gap flux.

[0055] L a is the length of the stator 10;

[0056] h m is the maximum radial thickness of the permanent magnet 21;

[0057] δ is the radial air-gap distance from the outer wall of the stator 10 to the inner wall of the permanent magnet 21;

[0058] h in is the thickness of the spacer sleeve 11 at the outer wall of the stator 10; when the medium conveyed by the general fluid machinery is gas, h in is zero; when the medium conveyed by the general fluid machinery is liquid, 0 < h in < 3 mm;

[0059] 2), The following formula is used to obtain the length increment of the effective permanent magnet 21

[0060] Due to the electric drive length increment and the length increment of the effective permanent magnet 21 are both related to (h m + δ + h in ), the following polynomial needs to be satisfied:

[0061]

[0062] In the formula, A1, A2, A3 and A4 are coefficients respectively, and their values are as follows:

[0063]

[0064] 3), The following formula is used to obtain the axial length L of the permanent magnet 21 m :

[0065]

[0066] Where:

[0067] is the length of the effective permanent magnet 21, and like the effective electric drive length of the stator 10 it is obtained by including the turn-linked armature winding at the end flux into the effective air-gap flux;

[0068] 4), From the axial length L of the permanent magnet 21 in step 3) m and the length L of the stator 10 in step 1) a , it can be known that L m > L a;

[0069] At this time, both ends of the permanent magnet 21 extend beyond both ends of the stator 10, so as to obtain the extension lengths ΔL of both ends of the permanent magnet 21 respectively. m1 and ΔL m2 , where ΔL m2 is slightly larger than ΔL m1 , and the two satisfy the following formula:

[0070]

[0071] When the power of the general fluid machinery is small, take the larger value. When the integrated general fluid machinery is a medium pump, the end of the permanent magnet 21 where ΔL m2 is located is the end where the load is located.

[0072] 4), Perform the trimming step of the permanent magnet 21:

[0073] Referring to Figure 2 as shown, the two ends of the permanent magnet 21 are of equal width. Compared with the two ends of the permanent magnet 21, the two side edges of the permanent magnet 21 are both trimming structures and satisfy the following relational formula:

[0074]

[0075] Where:

[0076] α is the included angle formed by the side edge of the permanent magnet 21 and the axis of the rotor 20; similar to the inclined rotor slots and skewed rotor bars of the traditional rotating shaft type rotor, the square plate-shaped or arc-shaped tile permanent magnet 21 is also attached to the inner wall of the rotor 20 in a skewed shape as a whole during installation, and a certain included angle can be naturally formed between its length direction and the axis of the rotor 20, that is, α;

[0077] β1 is the angle occupied by the trimming starting position on the permanent magnet 21 from the side edge in the cross-section of the rotor 20; β1 and the following β2 are based on the same principle, which are both the included angles formed by connecting the lines from each point to the axis of the rotor 20 and finding the two connecting lines. Specifically, refer to Figure 3 as shown;

[0078] β2 is the angle occupied between the two side edges of the permanent magnet 21 in the cross-section of the rotor 20, referring to Figure 3 as shown;

[0079] Δh m =h m -Δh m1 , h m is the maximum radial thickness of the permanent magnet 21, and Δh m1 is the radial thickness of the trimming starting position of the permanent magnet 21 from the side edge, referring to Figure 3 as shown;

[0080] R is the side chamfer of the permanent magnet 21, refer to Figure 3 as shown.

[0081] 5), Obtain the slot depth h of the stage slot 22 z and the slot width b z :

[0082] As Figure 3 shown, the slot depth h of the stage slot 22 z and the slot width b z satisfy the following formula:

[0083]

[0084] Example 1:

[0085] According to the above design method of the present invention, a set of motor parameters is obtained, specifically as follows:

[0086] a), On the basis of the known basic dimensions of the stator 10, after classifying the electric drive winding at the end flux into the air-gap effective flux, the effective electric drive length of the stator 10 is obtained At the same time, assuming that the conveying medium is water, that is, the general fluid machinery conveying medium is liquid at this time, h in is 1mm, h m is 4mm, δ = 2.5mm, L a = 66mm, through the formula:

[0087]

[0088] It can be known

[0089] b), It is also known that the length of the effective permanent magnet 21 A1, A2, A3 and A4 are 0, 0, 0.5, 0.02 respectively, and the polynomial can be changed to to obtain Through the formula:

[0090]

[0091] It can be known that L m = 64.75mm, rounded to 65mm.

[0092] c), Given L m = 65mm, L a = 66mm, and let to obtain ΔL m2 is 3.5mm, ΔL m1 is 4.5mm. Since this general fluid machinery is an axial flow pump, therefore ΔL m2One end of the permanent magnet 21 where the load is located is the end where the load is located, that is, the resultant force of the axial magnetic thrust of the entire pump body finally points to the end where the load of the pump body is located.

[0093] d), The side trimming structure of the permanent magnet satisfies the following relationship: α = 5°; β1 = 14°, β2 = 60°, and the trimming starting position satisfies △h m = 1.76mm, h m As described above is 4mm, and the trimming thickness satisfies R = 1.32mm, and at this time the fillet R at the edge satisfies

[0094] e), The rotor 20 contains evenly arranged stage slots 22, which satisfy the following relationship:

[0095] And

[0096] To verify the accuracy of the above analysis model and also to verify the effect of the present invention, the motor designed above was subjected to finite element analysis and simulation, and the results are as Figure 4 And Figure 5 Shown.

[0097] Conclusion:

[0098] From Figure 4 Among them, we can obtain that the rotor 20 designed according to the above design method of the present invention, combined with the current built-in stator 10, the obtained motor structure, that is, the general fluid module, has a great improvement in its electromagnetic torque: the average electromagnetic torque is 5.99 N·m, which is 8.51% higher than the original scheme (5.52 N·m). From the perspective of the fluctuation of the electromagnetic torque, the fluctuation of the improved scheme is relatively small, the improved motor runs relatively smoothly, and the working efficiency is also higher.

[0099] In addition, from Figure 5 The magnetic slot torque diagram shown: The magnetic slot torque of the improved scheme has obvious improvement compared with the original scheme, that is, -0.8 N·m to 0.8 N·m. The scheme of the present invention can make the magnetic slot torque of the motor structure fluctuate within the range of -0.42 N·m to 0.42 N·m, reducing by nearly 50%, which can be said to be very effective.

[0100] It can be seen that the performance of the motor improved by the scheme of the present invention has been significantly improved.

[0101] Of course, for those skilled in the art, the present invention is not limited to the details of the above-described exemplary embodiments, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0102] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0103] The technologies, shapes, and structures not described in detail in the present invention are all well-known technologies.

Claims

1. A rotor design method for an integrated general fluid machinery, characterized in that It includes the following steps: 1) The following formula is used to calculate the incremental length of the electric drive Wherein: is the effective electric drive length of the stator (10), obtained by incorporating the turn-linked electric drive winding at the end flux into the effective air-gap flux. L a is the length of the stator (10); h m is the maximum radial thickness of the permanent magnet (21); δ is the radial air-gap distance from the outer wall of the stator (10) to the inner wall of the permanent magnet (21); h in is the thickness of the isolation sleeve (11) at the outer wall of the stator (10); when the medium conveyed by the general fluid machinery is a gas, h in is zero; when the medium conveyed by the general fluid machinery is a liquid, 0 < h in < 3 mm; 2), obtain the length increment of the effective permanent magnet (21) using the following formula In the formula, A1, A2, A3, and A4 are coefficients respectively, and their values are as follows: 3) Calculate the axial length L of the permanent magnet (21) using the following formula m :[[]]END]] Wherein: is the length of the effective permanent magnet (21) and the effective electric drive length of the stator (10) similarly obtained by incorporating the turn-linked electric drive winding at the end flux into the effective air-gap flux 4), from the axial length L of the permanent magnet (21) in step 3) m and the length L of the stator (10) in step 1) a , it can be known that L m > L a ; At this time, both ends of the permanent magnet (21) extend out of both ends of the stator (10), so as to respectively obtain the extension lengths ΔL of both ends of the permanent magnet (21). m1 and ΔL m2 , and the two satisfy the following formula:

2. A rotor design method for an integrated general fluid machinery according to claim 1, characterized in that: When the integrated general fluid machinery is a medium pump, ΔL m2 One end of the permanent magnet (21) where m2 is located is the end where the load is located.

3. A rotor design method for an integrated general fluid machinery according to claim 1 or 2, characterized in that: The two ends of the permanent magnet (21) are of equal width; compared with the two ends of the permanent magnet (21), the two side edges of the permanent magnet (21) are both trimming structures, and satisfy the following relational expression: Wherein: α is the included angle formed by the side edge of the permanent magnet (21) and the axis of the rotor (20); β1 is the angle occupied by the trimming starting position distance from the side edge on the permanent magnet (21) in the cross-section of the rotor (20); β2 is the angle occupied between the two side edges of the permanent magnet (21) in the cross-section of the rotor (20); Δh m = h m -Δh m1 ,h m is the maximum radial thickness of the permanent magnet (21), and Δh m1 is the radial thickness of the starting position of trimming the permanent magnet (21) from the side. R is the chamfer of the side edge of the permanent magnet (21).

4. A rotor design method for an integrated general fluid machine according to claim 3, characterized in that: The permanent magnet (21) is in the shape of a square plate or an arc-shaped tile.

5. A general fluid module applying the rotor design method for an integrated general fluid machine according to claim 3, characterized in that: The general fluid module includes a stator (10) and a rotor (20) coaxially sleeved outside the stator (10). The outer wall of the rotor (20) is integrally fixed with blades or teeth; each permanent magnet is sequentially and evenly arranged around the axis of the rotor (20) at the inner wall of the rotor (20), and there is a movable gap with the isolation sleeve (11) coaxially fixed at the outer wall of the stator (10); in the cross-section of the rotor (20), a set of concave stage grooves (22) are respectively arranged at the inner wall of the rotor (20) where the two side edges of each permanent magnet (21) are located, and the stage grooves (22) penetrate through the rotor (20) and the groove length direction is parallel to the side edge of the permanent magnet (21); The groove depth h of the said stage groove (22) z and the groove width b z satisfy the following formula:

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