Rotor structure and motor

Abstract

The invention provides a rotor structure and a motor. The rotor structure comprises rotor end sections (1), a rotor middle section (2) and permanent magnets (3), and the rotor middle section (2) is located between the two rotor end sections (1) in the axial direction of the rotor. The rotor end section (1) and the rotor middle section (2) are provided with through mounting grooves, the permanent magnets (3) are mounted in the mounting grooves, the axial height of the rotor end section (1) is y, the axial height of the rotor middle section (2) is x, the axial height of the permanent magnets (3) is z, and x < = z < = (x + 2 * y). According to the rotor structure, the magnetic gathering effect of the motor can be effectively improved, and the magnetic leakage of the end parts of the permanent magnets is weakened.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a rotor structure and a motor. Background Art

[0002] With the improvement of motor energy efficiency standards, higher requirements are placed on the energy efficiency level of motors. For permanent magnet motors, the efficiency and high torque density of the motors need to be further improved.

[0003] At present, there are two technical means to improve motor efficiency and torque density. One is to embed permanent magnets to obtain a larger air gap flux and a larger magnetic flux. However, due to the fixed rotor magnetic circuit structure, the energy efficiency improvement is limited. Another means is to use the rotor structure to increase the motor salient pole ratio and increase the motor's reluctance torque to compensate for the lack of permanent magnet torque. Its efficiency can be comparable to that of a permanent magnet motor, but it usually requires a larger rotor volume, which will make the motor torque density inferior to that of a permanent magnet motor.

[0004] Therefore, for current motors, how to further achieve higher efficiency and higher torque density is an urgent problem to be solved. Summary of the invention

[0005] The main purpose of the present invention is to provide a rotor structure and a motor, which can effectively improve the magnetic field concentration effect of the motor and weaken the magnetic leakage at the end of the permanent magnet.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a rotor structure is provided, comprising a rotor end section, a rotor middle section and a permanent magnet. Along the axial direction of the rotor, the rotor middle section is located between the two rotor end sections; the rotor end section and the rotor middle section are provided with penetrating mounting grooves, and the permanent magnet is installed in the mounting grooves. The axial height of the rotor end section is y, the axial height of the rotor middle section is x, and the axial height of the permanent magnet is z, then x≤z≤(x+2*y).

[0007] Further, z=(x+2*y).

[0008] Furthermore, the middle section of the rotor is formed by laminating silicon steel sheets, and the end sections of the rotor are formed by injection molding of plastic magnetic powder.

[0009] Furthermore, the rotor structure is provided with a through hole, and the through hole passes through the rotor end section and the rotor middle section.

[0010] Furthermore, the middle section of the rotor is a magnetic conductive component, and the end sections of the rotor and the permanent magnets are magnetic flux sources.

[0011] Furthermore, the permanent magnets are magnetized tangentially, and the rotor end segments are magnetized alternately along the axial direction of the rotor along the N and S poles.

[0012] Furthermore, a limiting protrusion is provided on the outer circumferential side of the rotor end section or the rotor middle section, and the limiting protrusion extends laterally from both circumferential sides of the rotor end section or the rotor middle section to form a radial limit for the permanent magnet.

[0013] Furthermore, the outer peripheral wall of the rotor end section or the rotor middle section includes a plurality of arc surfaces arranged at intervals, and along the circumferential direction, the distance between the arc surfaces and the central axis of the rotor decreases from the middle to both ends.

[0014] Furthermore, on a plane perpendicular to the axial direction of the rotor end section, the minimum inner diameter of the rotor end section is Di1, the inner diameter of the rotor middle section is Di2, and Di2≤Di1.

[0015] Further, on a plane perpendicular to the axial direction of the rotor end section, the maximum value of the outer diameter of the rotor end section is Do1, the maximum value of the outer diameter of the rotor middle section is Do2, and Do2≥Do1.

[0016] Further, Do2=Do1.

[0017] Furthermore, under each rotor pole, the magnetic directions of the permanent magnets and the rotor end segments repel each other on the rotor middle segment.

[0018] Furthermore, the rotor structure is filled with molding compound at the end and the inner gap and is molded into a whole.

[0019] According to another aspect of the present invention, a motor is provided, comprising a stator structure and a rotor structure, wherein the rotor structure is the above-mentioned rotor structure.

[0020] By applying the technical solution of the present invention, the rotor structure includes a rotor end section, a rotor middle section and a permanent magnet. Along the axial direction of the rotor, the rotor middle section is located between the two rotor end sections; the rotor end section and the rotor middle section are provided with penetrating mounting grooves, and the permanent magnet is installed in the mounting grooves. The axial height of the rotor end section is y, the axial height of the rotor middle section is x, and the axial height of the permanent magnet is z, then x≤z≤(x+2*y).

[0021] In this rotor structure, the rotor is divided into rotor end sections and rotor middle sections, which can reduce the eddy current loss of the rotor core. The permanent magnets are inserted into the mounting grooves of the rotor end sections and the rotor middle sections, and the tangential surfaces of the permanent magnets and the axial surfaces of the rotor end sections can be used to provide magnetic flux for the motor at the same time, which can improve the magnetic field concentration effect of the motor. The axial heights and relative positions of the rotor end sections, the rotor middle sections and the permanent magnets are limited, so that the magnetic lines of force generated by the tangential surfaces of the permanent magnets and the axial surfaces of the rotor end sections repel each other on the rotor middle section, so that the magnetic lines of force generated by the two can only choose to enter the air gap and become the main magnetic flux, which can weaken the end leakage magnetic flux of the permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 An exploded structural diagram showing a rotor structure of an embodiment of the present invention;

[0024] Figure 2 A three-dimensional structural diagram showing a rotor structure of an embodiment of the present invention;

[0025] Figure 3 A side structural diagram showing a rotor structure of an embodiment of the present invention;

[0026] Figure 4 A top view of a rotor structure according to an embodiment of the present invention is shown;

[0027] Figure 5 A three-dimensional structural diagram of a rotor assembly according to an embodiment of the present invention is shown;

[0028] Figure 6 A top structural diagram of a rotor assembly according to an embodiment of the present invention is shown;

[0029] Figure 7 A three-dimensional structural diagram of a rotor assembly according to an embodiment of the present invention is shown;

[0030] Figure 8 An exploded structural diagram of a rotor assembly according to an embodiment of the present invention is shown;

[0031] Fig. 9 A comparison diagram of magnetic concentration coefficients of a motor according to an embodiment of the present invention and a motor according to related art is shown;

[0032] Fig.10 A comparison diagram of the leakage flux at the end of the permanent magnet of the motor of the embodiment of the present invention and the motor of the related art is shown;

[0033] Fig.11 A comparison diagram of rotor losses of a motor according to an embodiment of the present invention and a motor according to related art is shown;

[0034] Fig.12 A comparison diagram of no-load flux linkage between a motor according to an embodiment of the present invention and a motor in the related art is shown;

[0035] Fig.13 A comparison diagram of air gap flux density between a motor according to an embodiment of the present invention and a motor according to a related art is shown; and

[0036] Fig.14 A torque-current characteristic comparison diagram of the motor according to the embodiment of the present invention and the motor according to the related art is shown.

[0037] The above drawings include the following reference numerals:

[0038] 1. Rotor end section; 2. Rotor middle section; 3. Permanent magnet; 4. Through hole; 5. Limiting protrusion. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] See also Figures 1 to 8 As shown, according to an embodiment of the present invention, the rotor structure includes a rotor end segment 1, a rotor middle segment 2 and a permanent magnet 3. Along the axial direction of the rotor, the rotor middle segment 2 is located between two rotor end segments 1; the rotor end segment 1 and the rotor middle segment 2 are provided with a through installation groove, and the permanent magnet 3 is installed in the installation groove. The axial height of the rotor end segment 1 is y, the axial height of the rotor middle segment 2 is x, and the axial height of the permanent magnet 3 is z, then x≤z≤x+2*y.

[0041] In the rotor structure, the rotor is divided into rotor end section 1 and rotor middle section 2, which can reduce the eddy current loss of the rotor core. Fig.11 As shown, compared with the motor of the related art, the rotor loss of the motor adopting the rotor structure of the embodiment of the present invention is reduced by more than 35%; the permanent magnet 3 is inserted into the installation grooves of the rotor end section 1 and the rotor middle section 2, and the tangential surface of the permanent magnet 3 and the axial surface of the rotor end section 1 can be used to provide magnetic flux for the motor at the same time, which can improve the magnetic field concentration effect of the motor; the axial height and relative position of the rotor end section 1, the rotor middle section 2 and the permanent magnet 3 are limited, so that the magnetic lines of force generated by the tangential surface of the permanent magnet 3 and the axial surface of the rotor end section 1 repel each other on the rotor middle section 2, so that the magnetic lines of force generated by the two can only choose to enter the air gap and become the main magnetic flux, which can weaken the end leakage magnetic flux of the permanent magnet, such as Fig.10 As shown, compared with the motor in the related art, the leakage flux at the permanent magnet end of the motor using the rotor structure of the embodiment of the present invention is reduced by more than 30%.

[0042] In one embodiment, z=(x+2*y).

[0043] In one embodiment, the rotor middle section 2 is formed by laminating silicon steel sheets, and the rotor end section 1 is formed by injection molding of plastic magnetic powder. The rotor middle section 2 is a magnetic conductive component, and the rotor end section 1 and the permanent magnet 3 are magnetic flux sources. The rotor middle section 2 provides a flow path for the magnetic flux of the rotor end section 1 and the permanent magnet 3.

[0044] In one embodiment, a through hole 4 is provided on the rotor structure, and the through hole 4 passes through the rotor end section 1 and the rotor middle section 2. The through hole 4 is used to fix the rotor end section 1 and the rotor middle section 2 together, and can realize the rotor assembly positioning.

[0045] In one embodiment, the permanent magnet 3 is magnetized tangentially, and the rotor end segment 1 is magnetized alternately along the axial NS poles of the rotor. In this embodiment, the permanent magnet 3 is set to be magnetized tangentially, and the rotor end segment 1 is magnetized axially, which can achieve the continuity of the magnetic flux of the permanent magnet 3 and the rotor end segment 1, so that the two can more effectively provide magnetic flux for the motor together, effectively increasing the motor output.

[0046] In one embodiment, on a plane perpendicular to the axial direction of the rotor end section 1, the minimum inner diameter of the rotor end section 1 is Di1, the inner diameter of the rotor middle section 2 is Di2, and Di2≤Di1. The inner hole of the rotor needs to be assembled with a rotating shaft, and the inner hole of the rotor end needs to be filled with plastic sealing material to ensure the overall strength of the rotor. On the one hand, the above-mentioned dimensional relationship can make way for the assembly of the rotating shaft; on the other hand, without affecting the assembly of the rotating shaft, the inner hole of the rotor end section 1 can be filled with plastic sealing material or other materials to enhance the strength of the rotor.

[0047] In one embodiment, a limiting protrusion 5 is provided on the outer circumferential side of the rotor end segment 1 or the rotor middle segment 2 , and the limiting protrusion 5 extends laterally from both circumferential sides of the rotor end segment 1 or the rotor middle segment 2 to form a radial limit for the permanent magnet 3 .

[0048] In this embodiment, the limiting protrusion 5 is located at the outermost periphery of the rotor middle section 2, and extends circumferentially from the two side surfaces in the circumferential direction of the rotor middle section 2, and the two limiting protrusions 5 extending toward each other are arranged at intervals, thereby forming an open slot structure while radially limiting the permanent magnet 3, thereby reducing the leakage magnetic flux of the permanent magnet 3 at the outer periphery of the rotor.

[0049] In one embodiment, the outer peripheral wall of the rotor end section 1 or the rotor middle section 2 includes a plurality of arc surfaces arranged at intervals, and along the circumferential direction, the distance between the arc surfaces and the central axis of the rotor decreases from the middle to both ends.

[0050] In this embodiment, since the rotor end segment 1 and the rotor middle segment 2 form an open slot structure, the outer peripheral structure of the rotor is not a full circle, but a plurality of arc segments arranged at intervals. The middle of each arc segment protrudes radially outward to form an arc structure that is misaligned with the center of the rotor outer circle. This can improve the air gap magnetic density between the stator and the rotor, is more conducive to forming a sine curve, and improves the working performance of the motor.

[0051] In one embodiment, on a plane perpendicular to the axial direction of the rotor end segment 1 , the maximum value of the outer diameter of the rotor end segment 1 is Do1 , the maximum value of the outer diameter of the rotor middle segment 2 is Do2 , and Do2 ≥ Do1 .

[0052] In one embodiment, Do2=Do1.

[0053] For the motor, on the one hand, the stator structure is sleeved on the outside of the rotor structure, and an air gap is set between the rotor structure and the stator structure. This setting can make way for the assembly of the stator structure; on the other hand, the magnetic circuit area of ​​the limit protrusion 5 is small and easy to saturate, and the position of the limit protrusion 5 is close to the air gap, which is the magnetic flux gathering position. The iron loss here is large, and Do2≥Do1 can make the limit protrusion 5 not in the magnetic flux action range of the rotor end section 1, reducing the iron loss of the motor. In motors with a small proportion of iron loss, Do2=Do1 is a better choice.

[0054] In one embodiment, under each rotor pole, the magnetic directions of the permanent magnet 3 and the rotor end segment 1 repel each other on the rotor middle segment 2 .

[0055] The mutually repelling magnetic lines of force of the permanent magnet 3 and the rotor end segment 1 make the magnetic lines of force generated by the two only enter the air gap and become the main magnetic flux, which can weaken the end magnetic leakage of the permanent magnet.

[0056] In one embodiment, the rotor structure is filled with molding compound at the end and the internal gap and molded into a whole, which can ensure the overall structural strength of the rotor assembly.

[0057] See also Fig. 9 As shown, compared with the motor in the related art, the magnetic concentration coefficient of the motor using the rotor structure of the embodiment of the present invention is increased by more than 60%, and the magnetic concentration performance is significantly improved.

[0058] See also Fig.10 As shown, compared with the motor in the related art, the permanent magnet end leakage flux of the motor adopting the rotor structure of the embodiment of the present invention is reduced by more than 30%, and when z / (x+2*y)≤1, the permanent magnet end leakage flux is small.

[0059] See also Fig.11 As shown, compared with the motor in the related art, the rotor loss of the motor adopting the rotor structure of the embodiment of the present invention is reduced by more than 35%, and the motor performance is improved.

[0060] See also Fig.12 As shown, compared with the motor in the related art, the no-load flux of the motor using the rotor structure of the embodiment of the present invention is increased by more than 50%, which effectively increases the no-load flux and improves the motor performance.

[0061] See also Fig.13As shown, compared with the motor in the related art, the air gap flux density of the motor using the rotor structure of the embodiment of the present invention is increased by more than 60%, which effectively increases the air gap flux density, improves the motor torque density, and increases the motor output.

[0062] See also Fig.14 As shown, compared with the motors of the related art, the torque multiple of the motor adopting the rotor structure of the embodiment of the present invention becomes increasingly advantageous as the current increases, thereby achieving a larger torque multiple, improving the motor torque density, and increasing the motor output.

[0063] According to an embodiment of the present invention, the motor includes a stator structure and a rotor structure, and the rotor structure is the above-mentioned rotor structure.

[0064] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0065] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rotor structure, characterized in that: The invention comprises a rotor end section (1), a rotor middle section (2) and a permanent magnet (3); along the axial direction of the rotor, the rotor middle section (2) is located between the two rotor end sections (1); the rotor end section (1) and the rotor middle section (2) are provided with a penetrating installation groove, the permanent magnet (3) is installed in the installation groove, the axial height of the rotor end section (1) is y, the axial height of the rotor middle section (2) is x, and the axial height of the permanent magnet (3) is z, then x≤z≤(x+2*y).

2. The rotor structure according to claim 1, characterized in that: z=(x+2*y).

3. The rotor structure according to claim 1, characterized in that: The rotor middle section (2) is formed by laminating silicon steel sheets, and the rotor end section (1) is formed by injection molding of plastic magnetic powder.

4. The rotor structure according to claim 1, characterized in that: The rotor structure is provided with a through hole (4), and the through hole (4) passes through the rotor end section (1) and the rotor middle section (2).

5. The rotor structure according to claim 1, characterized in that: The rotor middle section (2) is a magnetic conductive component, and the rotor end section (1) and the permanent magnet (3) are magnetic flux sources.

6. The rotor structure according to claim 1, characterized in that: The permanent magnet (3) is magnetized tangentially, and the rotor end segment (1) is magnetized alternately along the axial direction of the rotor with N and S poles.

7. The rotor structure according to claim 1, characterized in that: A limiting protrusion (5) is provided on the outer circumferential side of the rotor end section (1) or the rotor middle section (2); the limiting protrusion (5) extends laterally from both circumferential sides of the rotor end section (1) or the rotor middle section (2) and forms a radial limit for the permanent magnet (3).

8. The rotor structure according to claim 1, characterized in that: The outer peripheral wall of the rotor end section (1) or the rotor middle section (2) comprises a plurality of arc surfaces arranged at intervals, and along the circumferential direction, the distance between the arc surfaces and the rotor central axis decreases from the middle to both ends.

9. The rotor structure according to any one of claims 1 to 8, characterized in that: On a plane perpendicular to the axial direction of the rotor end section (1), the minimum inner diameter of the rotor end section (1) is Di1, the inner diameter of the rotor middle section (2) is Di2, and Di2≤Di1.

10. The rotor structure according to any one of claims 1 to 8, characterized in that: On a plane perpendicular to the axial direction of the rotor end section (1), the maximum value of the outer diameter of the rotor end section (1) is Do1, the maximum value of the outer diameter of the rotor middle section (2) is Do2, and Do2≥Do1.

11. The rotor structure according to claim 10, characterized in that: Do2=Do1.

12. The rotor structure according to claim 6, characterized in that: Under each rotor pole, the magnetic directions of the permanent magnet (3) and the rotor end section (1) repel each other on the rotor middle section (2).

13. The rotor structure according to claim 1, characterized in that: The rotor structure is filled with molding compound at the end and the inner gap and is molded into a whole.

14. A motor, comprising a stator structure and a rotor structure, characterized in that: The rotor structure is the rotor structure according to any one of claims 1 to 13.

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