Single-phase permanent magnet motor rotor

Abstract

The invention relates to the field of single-phase permanent magnet motors, and discloses a single-phase permanent magnet motor rotor, which comprises a rotor punching sheet, a plurality of magnet groups are symmetrically arranged on the rotor punching sheet, the plurality of magnet groups are distributed along the circumferential direction of the rotor punching sheet, and each magnet group comprises two strip-shaped permanent magnets; the rotor punching sheet located at the inner side end of each permanent magnet is provided with a first weight reduction ventilation hole, the rotor punching sheet between the two permanent magnets in each group is provided with a second weight reduction ventilation hole, and the rotor punching sheet between every two adjacent magnet groups is provided with at least one magnetism gathering hole and at least one magnetism isolating hole. And the rotor punching sheet at the outer side end of each permanent magnet is provided with an anti-magnetic short-circuit magnetic hole. The rotor has the advantages of high strength, small unilateral magnetic pulling force, high power density, low noise, low heating and the like.

Description

Technical Field

[0001] The present invention relates to the field of single-phase permanent magnet motors, and particularly to a rotor of a single-phase permanent magnet motor. Background Art

[0002] A single-phase permanent magnet motor is a synchronous motor that uses permanent magnets as rotor poles, and its stator winding is powered by a single-phase AC power supply. Currently, existing single-phase permanent magnet motors all have a common problem of poor waveform due to the presence of third harmonics; at the same time, the magnetic field cannot rotate, so the pulsation is severe during the loading process, manifested as large vibration and noise. At the same time, due to the presence of the pulsating magnetic field, the voltage regulation rate of the motor during the loading process is extremely large.

[0003] Therefore, existing single-phase permanent magnet motors have at least the defects of large volume, low power density, high voltage regulation rate, poor waveform, and severe vibration and noise. Summary of the Invention

[0004] The purpose of the present invention is to provide a rotor of a single-phase permanent magnet motor to solve the problems that existing single-phase permanent magnet motors have at least large volume, low power density, high voltage regulation rate, poor waveform, and severe vibration and noise.

[0005] To achieve the above-mentioned invention purpose, the technical solution adopted by the present invention is as follows: The present invention provides a rotor of a single-phase permanent magnet motor, including: a rotor punching sheet, on which several groups of magnet groups are symmetrically arranged. The several groups of magnet groups are distributed along the circumferential direction of the rotor punching sheet, and each group of magnet groups includes two strip-shaped permanent magnets; On the rotor punching sheet at the inner end of each permanent magnet, there are first weight-reducing ventilation holes, and on the rotor punching sheet between the two permanent magnets in each group, there are second weight-reducing ventilation holes. And on the rotor punching sheet between every two adjacent groups of magnet groups, there are at least one magnetic concentrating hole and at least one magnetic isolating hole. On the rotor punching sheet at the outer end of each permanent magnet, there are anti-magnetic short-circuit magnetic holes.

[0006] Preferably, it further includes: a central rotating shaft, which is inserted into the rotor punching sheet. At both ends of the rotor punching sheet, there are end pressing plates. The end pressing plates are fixed on the end faces of the rotor punching sheet through several damping tie rods. The end pressing plates are provided with through holes corresponding to the first weight-reducing ventilation holes and the second weight-reducing ventilation holes.

[0007] Preferably, both the first weight-reducing ventilation holes and the anti-magnetic short-circuit magnetic holes are triangular holes, the second weight-reducing ventilation holes are round holes, and the magnetic isolating holes are round holes and / or square holes.

[0008] Preferably, there is a magnetic isolation hole between two first weight-reducing ventilation holes at the inner ends of two adjacent permanent magnets in different groups. The magnetic isolation hole is a square hole, and the value range of the distance Q between the magnetic isolation hole and the two first weight-reducing ventilation holes at the inner ends of two adjacent permanent magnets in different groups is (0.8 mm, 3.5 mm).

[0009] Preferably, the included angle between every two adjacent magnet groups is 90° to 116.2°.

[0010] Preferably, there are two magnetic concentrating holes provided on the rotor punching sheet between every two adjacent magnet groups. The cross section of each magnetic concentrating hole is in an elongated structure, and each magnetic concentrating hole is perpendicular to the side wall of the permanent magnet adjacent to the magnetic concentrating hole.

[0011] Preferably, the perpendicular distance from each magnetic concentrating hole to the inner end edge of the permanent magnet adjacent to the magnetic concentrating hole is: H = L * m; In the formula, H is the perpendicular distance from each magnetic concentrating hole to the inner end edge of the permanent magnet adjacent to the magnetic concentrating hole, L is the length of the cross section of each permanent magnet, m is the first coefficient, and the value range of the first coefficient m is (0.3, 0.7).

[0012] Preferably, the minimum distance between two magnetic concentrating holes between two permanent magnets in the same group is determined according to the distance between the two permanent magnets in this group; Among them, the distance between the two permanent magnets in this group is: G = k * π * D; In the formula, G is the distance between two permanent magnets in each group, k is the third coefficient, the value range of the third coefficient k is (0.05, 0.21), π is the pi, and D is the outer diameter of the rotor punching sheet; Then, the minimum distance between two magnetic concentrating holes between two permanent magnets in the same group is: E = b * G; In the formula, E is the minimum distance between two magnetic concentrating holes between two permanent magnets in the same group, b is the second coefficient, and the value range of the second coefficient b is (0.45, 0.7).

[0013] Preferably, there are cuts extending along the axial direction of the rotor punching sheet provided on the outer wall of the rotor punching sheet outside each magnet group, and a through groove is provided in the middle of the cut.

[0014] Preferably, the depth of the cut is less than 10 mm.

[0015] The beneficial effects of the present invention are mainly reflected in: 1. The rotor punching sheet of the present invention is provided with a first weight-reducing ventilation hole and a second weight-reducing ventilation hole, which can not only reduce the weight of the rotor punching sheet, but also form a ventilation cavity during the rotation of the rotor punching sheet, which can quickly take away the heat inside the iron core. Moreover, a number of magnet groups are symmetrically arranged on the rotor punching sheet, so that the rotor has high symmetry and has the advantages of high strength, small unilateral magnetic pull, high power density, low noise, low heat generation, etc. 2. The rotor punching sheet of the present invention is provided with magnetic focusing holes, which can play a role in gathering the magnetic field generated by the permanent magnets, can contribute to the motor waveform being in a natural sine shape, greatly reduce the third harmonic, fifth harmonic and seventh harmonic. For a single-phase permanent magnet motor, the inherent property of the third harmonic directly affects the waveform and noise of the motor and is also an important source of loss. 3. The rotor punching sheet of the present invention is also provided with magnetic isolation holes, which can isolate the magnetic circuit to increase the magnetic resistance, create local cavities, optimize the air-gap magnetic field distribution, and further optimize the magnetic circuit distribution under load. 4. The rotor punching sheet of the present invention is also provided with anti-magnetic short-circuit magnetic holes, which can prevent magnetic short-circuit from causing permanent demagnetization and reduce magnetic leakage at the same time. Description of the Drawings

[0016] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings: Figure 1 is the front view of the assembly structure of the rotor of a single-phase permanent magnet motor provided by an embodiment of the present invention; Figure 2 is the side view of the assembly structure of the rotor of a single-phase permanent magnet motor provided by an embodiment of the present invention; Figure 3 is the overall structural schematic diagram of the rotor punching sheet provided by an embodiment of the present invention; Figure 4 is the overall structural schematic diagram of the end pressing plate provided by an embodiment of the present invention; Figure 5 is the size marking schematic diagram of the rotor punching sheet provided by an embodiment of the present invention; Figure 6 is the curve graph of the full-load output torque changing with the angle provided by an embodiment of the present invention; Figure 7 is the curve graph of the full-load current changing with the angle provided by an embodiment of the present invention; Figure 8 is the distribution diagram of the air-gap magnetic field changing with the angle provided by an embodiment of the present invention; Figure 9 is the THD simulation diagram provided by an embodiment of the present invention; Figure 10 is the distribution diagram of the tooth groove rotation varying with the angle provided by an embodiment of the present invention; Figure 11 is the motor operation vector diagram provided by an embodiment of the present invention; Legend: 1. Rotor punching sheet; 2. Central rotating shaft; 3. End pressing plate; 4. Damping tie rod; 5. Tie rod hole; 6. Permanent magnet; 7. First weight-reducing ventilation hole; 8. Second weight-reducing ventilation hole; 9. Magnetic concentrating hole; 10. Magnetic isolation hole; 11. Anti-magnetic short-circuit magnetic hole; 12. Through hole; 13. Notch; 14. Through groove. Specific embodiments

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the present invention in combination with the descriptions of the accompanying drawings and the embodiments or the prior art. Obviously, the following descriptions of the structures of the accompanying drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. It should be noted here that the descriptions of these embodiment modes are used to help understand the present invention, but do not constitute a limitation to the present invention.

[0018] Figure 1 is the front view of the assembly structure of the rotor of a single-phase permanent magnet motor provided by an embodiment of the present invention. As Figure 1 shown, a single-phase permanent magnet motor rotor includes: a rotor punching sheet 1, a central rotating shaft 2, and two end pressing plates 3. The two end pressing plates 3 are fixed on the end face of the rotor punching sheet 1 by a plurality of damping tie rods 4. In this embodiment, 12 damping tie rods 4 are provided and symmetrically distributed in the circumferential direction of the rotor punching sheet 1. At the same time, the rotor punching sheet 1 is provided with 12 tie rod holes 5, and the 12 damping tie rods 4 are inserted into the tie rod holes 5. The through holes 12 at both ends of the damping tie rods 4 are bolted to press the end pressing plates 3 on the rotor punching sheet 1. Therefore, the single-phase permanent magnet motor rotor in this embodiment has high symmetry, and has the advantages of high strength, small unilateral magnetic pull force, high power density, low noise, and low heat generation. Since the damping tie rods 4 are embedded in the center, when the motor has a sudden torque change, the damping elastic deformation is used to keep the torque transition smooth and reduce the impact on the end bearings and the central rotating shaft 2.

[0019] As Figure 2As shown, a plurality of magnet groups are symmetrically arranged on the rotor punching 1, and the plurality of magnet groups are distributed along the circumference of the rotor punching 1, and each magnet group includes two permanent magnets 6 in the form of strips; in the present embodiment, a total of four magnet groups are arranged, each group has two permanent magnets 6, and a total of eight permanent magnets 6 are arranged, and three tie rod holes 5 are arranged on the rotor punching 1 between two adjacent magnet groups, and among the three tie rod holes 5, the distance from the middle tie rod hole 5 to the axis of the rotor punching 1 is smaller than the distance from the tie rod holes 5 on both sides to the axis of the rotor punching 1, and the distance from the tie rod holes 5 on both sides to the axis of the rotor punching 1 is the same, and this deployment structure makes the rotor of the single-phase permanent magnet motor highly symmetrical.

[0020] As a further optimization of this embodiment, Figure 3 As shown, a first weight-reducing ventilation hole 7 is provided on the rotor punching 1 located at the inner end of each permanent magnet 6, and a second weight-reducing ventilation hole 8 is provided on the rotor punching 1 between each group of two permanent magnets 6, and at least one magnetic focusing hole 9 and at least one magnetic isolation hole 10 are provided on the rotor punching 1 between each two adjacent groups of magnets, and a magnetic short-circuit prevention magnetic hole 11 is provided on the rotor punching 1 located at the outer end of each permanent magnet 6.

[0021] In this embodiment, the first weight-reducing ventilation hole 7 and the anti-magnetic short-circuit magnetic hole 11 are both triangular holes, the second weight-reducing ventilation hole 8 is a circular hole, and the magnetic isolation hole 10 is a circular hole and / or a square hole.

[0022] The first weight-reducing ventilation hole 7 and the second weight-reducing ventilation hole 8 can not only reduce the weight of the rotor punching 1, but also form ventilation holes during the rotation of the rotor punching 1 to quickly take away the heat inside the iron core.

[0023] Among them, the magnetic focusing hole 9 can gather the magnetic field generated by the permanent magnet 6, which can make the motor waveform naturally sinusoidal and greatly reduce the third harmonic, fifth harmonic and seventh harmonic. For single-phase permanent magnet motors, the inherent properties of the third harmonic directly affect the waveform and noise of the motor and are also an important source of loss.

[0024] Among them, the magnetic isolation hole 10 can isolate the magnetic circuit to increase the magnetic resistance, create local holes, optimize the air gap magnetic field distribution, and further optimize the load magnetic circuit distribution.

[0025] The anti-magnetic short-circuit magnetic hole 11 can prevent permanent demagnetization caused by magnetic short circuit and reduce magnetic leakage.

[0026] In this embodiment, if Figure 4 As shown, the end pressure plate 3 is provided with through holes 12 corresponding to the first weight-reducing ventilation holes 7 and the second weight-reducing ventilation holes 8 .

[0027] As a further optimization of this embodiment, there is a magnetic isolation hole 10 between two first weight-reducing ventilation holes 7 at the inner ends of two adjacent permanent magnets 6 in different groups. The magnetic isolation hole 10 is a square hole, and the value range of the distance Q between the magnetic isolation hole 10 and the two first weight-reducing ventilation holes 7 at the inner ends of two adjacent permanent magnets 6 in different groups is (0.8 mm, 3.5 mm), as Figure 5 shown.

[0028] The magnetic isolation hole 10 can isolate the magnetic circuit to increase the magnetic resistance, create local cavities, prevent local short-circuit of the effective magnetic flux; reduce the magnetic density here, optimize the air-gap magnetic field distribution, and further optimize the magnetic circuit distribution under load; it can also further reduce the weight and form lightweight punching sheets; at the same time, the cavity here forms a ventilation cavity during the rotation process, which can quickly take away the heat inside the iron core.

[0029] As a further optimization of this embodiment, the included angle Y between every two adjacent magnet groups is 90° to 116.2°, as Figure 5 shown.

[0030] As a further optimization of this embodiment, two magnetic focusing holes 9 are provided on the rotor punching sheet 1 between every two adjacent magnet groups, and the cross-section of each magnetic focusing hole 9 is in an elongated structure, and each magnetic focusing hole 9 is perpendicular to the side wall of the permanent magnet 6 adjacent to the magnetic focusing hole 9.

[0031] As Figure 5 shown, the perpendicular distance from each magnetic focusing hole 9 to the inner end edge of the permanent magnet 6 adjacent to the magnetic focusing hole 9 is: H = L * m; In the formula, H is the perpendicular distance from each magnetic focusing hole 9 to the inner end edge of the permanent magnet 6 adjacent to the magnetic focusing hole 9, L is the length of the cross-section of each permanent magnet 6, m is the first coefficient, and the value range of the first coefficient m is (0.3, 0.7); in this embodiment, the length L of the cross-section of each permanent magnet 6 is (10 mm, 65 mm), and the width W of the cross-section of each permanent magnet 6 is (4.5 mm, 30.5 mm).

[0032] At the same time, the minimum distance between the two magnetic focusing holes 9 between the two permanent magnets 6 in the same group is determined according to the distance between the two permanent magnets 6 in this group; Among them, the distance between the two permanent magnets 6 in this group is: G = k * π * D; In the formula, G is the distance between the two permanent magnets 6 in each group, k is the third coefficient, the value range of the third coefficient k is (0.05, 0.21), π is the pi, and D is the outer diameter of the rotor punching sheet 1; Then, the minimum distance between the two magnetic focusing holes 9 between the two permanent magnets 6 in the same group is: E = b * G; Wherein, E is the minimum distance between two magnetic concentrating holes 9 between two permanent magnets 6 in the same group, b is the second coefficient, and the value range of the second coefficient b is (0.45, 0.7).

[0033] In this embodiment, by optimizing the minimum distance between two magnetic concentrating holes 9, the functions of magnetic concentration and magnetic conduction can be further achieved, the air-gap magnetic field distribution can be further improved, the voltage waveform can be improved, and its sinusoidality can be increased; at the same time, a large amount of effective magnetic flux converges in the middle, further increasing the overload capacity of the motor and preventing the occurrence of the "peak shaving" phenomenon; further, due to the large amount of effective magnetic flux gathering, the voltage regulation rate during the load-carrying process will also be further optimized, and the magnetic circuit deviation will not occur prematurely, thereby effectively optimizing the voltage regulation rate and the load-carrying waveform.

[0034] As a further optimization of this embodiment, a notch 13 extending along the axial direction of the rotor punching sheet 1 is provided on the outer wall of the rotor punching sheet 1 located outside the magnet group of each group, and a through groove 14 is provided in the middle of the notch 13; and the depth of the notch 13 is less than 10 mm, that is, the depth X of the notch 13 is (0, 10 mm).

[0035] In this embodiment, the depth of the notch 13 can greatly improve the q-axis magnetic resistance, change the d, q-axis ratio, which is beneficial to reducing the reluctance torque, improving the waveform during the load-carrying process, and at the same time increasing the overload capacity of the motor. At the same time, the setting of the through groove 14 can further improve the radial magnetic resistance, improve the q-axis magnetic flux, increase the d-axis magnetic field leakage path, and increase the useful rate of magnetic flux linkage. Among them, the d-axis magnetic field refers to the magnetic field parallel to the rotor magnetic pole axis (i.e., the permanent magnet magnetic pole direction) in the motor. The d-axis magnetic field is mainly related to the excitation magnetic flux of the motor and reflects the magnetic field strength of the motor; the q-axis magnetic field refers to the magnetic field perpendicular to the rotor magnetic pole axis. The q-axis magnetic field is mainly related to the torque generation of the motor and reflects the ability of the motor to generate mechanical force.

[0036] The test parameters of the single-phase permanent magnet motor equipped with the rotor of the present invention are as follows:[[]]END]]

[0037] In Figure 6 , the abscissa is the angular position (Position), and the ordinate is the output torque (Torque) with the unit of N*m; in Figure 7 , the abscissa is the angular position (Position), and the ordinate is the current (Currents) with the unit of A; in Figure 8 , the abscissa is the angular position (Position), and the ordinate is the air-gap magnetic field (Airgap Flux Density) with the unit of T; in Figure 9where the abscissa is the harmonic order and the ordinate is the harmonic amplitude; in Figure 10 the abscissa is the angular position and the ordinate is the cogging torque, with the unit of N*m.

[0038] From the attached Figures 6 - 10 it can be seen that through simulation and measured data, it can be obtained that the output voltage of the present invention is a single-phase pure sine wave, the simulated value of the total voltage harmonic distortion rate THDu is 3.72 and the measured value is 4.09, both of which are less than the 10% standard of the single-phase excited motor in the military standard. Moreover, the present invention uses a permanent magnet as the excitation source, without excitation circuit loss, greatly increasing the motor efficiency. Since a permanent magnet is used as the excitation source, the load angle is small during the load-carrying process, only 18 - 22 degrees. From Figure 11 it can be seen that the power factor of the motor reaches above 0.98.

[0039] The above are only the embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A single-phase permanent magnet motor rotor, characterized in that, Comprising: A rotor punching sheet (1), on which several groups of magnet groups are symmetrically arranged. The several groups of magnet groups are distributed along the circumferential direction of the rotor punching sheet (1), and each group of magnet groups includes two strip-shaped permanent magnets (6); On the rotor punching sheet (1) at the inner end of each permanent magnet (6), there are first weight-reducing ventilation holes (7), and on the rotor punching sheet (1) between the two permanent magnets (6) in each group, there are second weight-reducing ventilation holes (8). And on the rotor punching sheet (1) between every two adjacent groups of magnet groups, there are at least one magnetic concentrating hole (9) and at least one magnetic isolation hole (10). On the rotor punching sheet (1) at the outer end of each permanent magnet (6), there is an anti-magnetic short-circuit magnetic hole (11).

2. The rotor of the single-phase permanent magnet motor according to claim 1, characterized in that, Also comprising: A central rotating shaft (2), which is inserted into the rotor punching sheet (1). At both ends of the rotor punching sheet (1), there are end pressing plates (3). The end pressing plates (3) are fixed on the end faces of the rotor punching sheet (1) through several damping pull rods (4). On the end pressing plates (3), there are through holes (12) corresponding to the first weight-reducing ventilation holes (7) and the second weight-reducing ventilation holes (8).

3. The rotor of the single-phase permanent magnet motor according to claim 1, characterized in that, Both the first weight-reducing ventilation holes (7) and the anti-magnetic short-circuit magnetic holes (11) are triangular holes, the second weight-reducing ventilation holes (8) are round holes, and the magnetic isolation holes (10) are round holes and / or square holes.

4. The rotor of the single-phase permanent magnet motor according to claim 3, characterized in that, There is a magnetic isolation hole (10) between the two first weight-reducing ventilation holes (7) at the inner ends of two adjacent permanent magnets (6) in different groups. This magnetic isolation hole (10) is a square hole, and the value range of the distance Q between this magnetic isolation hole (10) and the two first weight-reducing ventilation holes (7) at the inner ends of two adjacent permanent magnets (6) in different groups is (0.8 mm, 3.5 mm).

5. The rotor of the single-phase permanent magnet motor according to claim 1, characterized in that The included angle between every two adjacent groups of magnet groups is 90° - 116.2°.

6. The rotor of the single-phase permanent magnet motor according to claim 1, characterized in that, On the rotor punching sheet (1) between every two adjacent groups of magnet groups, there are two magnetic concentrating holes (9). The cross-section of each magnetic concentrating hole (9) is in an elongated structure, and each magnetic concentrating hole (9) is perpendicular to the side wall of the permanent magnet (6) adjacent to this magnetic concentrating hole (9).

7. The rotor of the single-phase permanent magnet motor according to claim 6, wherein The perpendicular distance from each magnetic concentrating hole (9) to the inner end edge of the permanent magnet (6) adjacent to this magnetic concentrating hole (9) is: H = L * m; In the formula, H is the perpendicular distance from each magnetic concentrating hole (9) to the inner end edge of the permanent magnet (6) adjacent to this magnetic concentrating hole (9), L is the length of the cross-section of each permanent magnet (6), m is the first coefficient, and the value range of the first coefficient m is (0.3, 0.7).

8. The rotor of the single-phase permanent magnet motor according to claim 7, characterized in that, The minimum distance between the two magnetic concentrating holes (9) between the two permanent magnets (6) in the same group is determined according to the distance between the two permanent magnets (6) in this group; Among them, the distance between the two permanent magnets (6) in this group is: G = k * π * D; In the formula, G is the distance between the two permanent magnets (6) in each group, k is the third coefficient, the value range of the third coefficient k is (0.05, 0.21), π is the pi, and D is the outer diameter of the rotor punching sheet (1). Then, the minimum distance between two magnetic focusing holes (9) between two permanent magnets (6) in the same group is: E = b * G; where E is the minimum distance between two magnetic focusing holes (9) between two permanent magnets (6) in the same group, b is the second coefficient, and the value range of the second coefficient b is (0.45, 0.7).

9. The rotor of the single-phase permanent magnet motor according to claim 1, characterized in that On the outer wall of the rotor punching sheet (1) located outside the magnet group of each group, there is a cut (13) extending along the axial direction of the rotor punching sheet (1), and a through groove (14) is provided in the middle of the cut (13).

10. The single-phase permanent magnet motor rotor according to claim 9, wherein, The depth of the cut (13) is less than 10 mm.

Images