Built-in magnet steel motor rotor, motor and air conditioner

Abstract

The application provides a magnetic steel built-in motor rotor, a motor and an air conditioner. The magnetic steel built-in motor rotor comprises a rotor core, a plurality of magnetic steel slots are arranged on the rotor core, the plurality of magnetic steel slots are arranged at intervals along the circumferential direction of the rotor core, a magnetic steel is arranged in each magnetic steel slot, any plane perpendicular to the axial direction of the rotor core is a projection radial plane, and the projection of the magnetic steel and the magnetic steel slot on the projection radial plane is a circular shape with matched sizes. According to the application, centrifugal tensile stress of the rotor lamination and the magnetic steel under high rotation speed can be significantly reduced without reducing the electromagnetic performance of the motor, the maximum rotation speed that can be borne by the rotor is improved, the rotor structure is compact, and the vibration of the rotor under high-speed operation is reduced.

Description

Technical Field

[0001] This invention belongs to the field of air conditioning technology, specifically relating to a magnet-embedded motor rotor, a motor, and an air conditioner. Background Technology

[0002] Compared to traditional motors, permanent magnet synchronous motors (PMSMs) offer advantages such as simple structure, high output efficiency, good speed regulation, and no environmental pollution, making them a major research direction for future ultra-high-speed motors. However, the problems of high noise levels and poor versatility of built-in magnets in PMSMs persist.

[0003] Existing permanent magnet synchronous motors with built-in magnet rotors and those incorporating such built-in magnet rotors, such as Figure 1 As shown, it is a rotor 10 with built-in magnets. The magnets 12 are rectangular, and the S-pole magnets and N-pole magnets are arranged alternately along the circumference of the iron core. The two ends of the magnets 12 have magnetic isolation grooves 11. With this built-in rotor, the magnets are subjected to large centrifugal tensile stress at high speeds, and the magnets are prone to damage. The maximum speed that the rotor can withstand is relatively low. Summary of the Invention

[0004] Therefore, the present invention provides a magnet-embedded motor rotor, motor, and air conditioner, which can overcome the shortcomings of related technologies where the magnets in the magnet-embedded rotor are rectangular, the magnets are subjected to large centrifugal tensile stress at high speeds, the magnets are prone to damage, and the maximum speed that the rotor can withstand is relatively low.

[0005] To address the aforementioned problems, the present invention provides a magnet-embedded motor rotor, comprising a rotor core, wherein a plurality of magnet slots are constructed on the rotor core, the plurality of magnet slots are arranged at intervals along the circumference of the rotor core, and each magnet slot is equipped with a magnet. Any plane perpendicular to the axial direction of the rotor core is a projection radial plane, and the projection of the magnet and the magnet slot on the projection radial plane is a circle of matching size.

[0006] In some embodiments, a positioning structure is provided between the magnet and the magnet groove.

[0007] In some embodiments, on the projected radial plane, the outer peripheral wall of the magnet has a positioning plane extending along its length direction, the distance from any point on the positioning plane to the geometric center of the magnet is no greater than the radius of the magnet, the groove wall of the magnet has a positioning wall segment extending radially inward, the positioning plane and the cylindrical segment of the magnet form a positioning point, at least one end of the positioning wall segment can abut against the positioning point, and the positioning plane and the positioning wall segment together constitute the positioning structure.

[0008] In some embodiments, the positioning wall segment has two sub-segments connected in a V shape, and a magnetic isolation gap is formed between the positioning wall segment and the opposite positioning plane.

[0009] In some embodiments, the positioning plane has two, and the two positioning planes are symmetric about the geometric center of the magnetic steel.

[0010] In some embodiments, the positioning wall segment has two, and the two positioning wall segments are symmetric about the geometric center of the magnetic steel slot.

[0011] In some embodiments, each magnetic pole of the rotor core has four magnetic steel slots, and the four magnetic steel slots are symmetrically arranged about the d-axis of the magnetic pole.

[0012] In some embodiments, the two magnetic steel slots on the two sides of the d-axis have their centers of circle on a straight line, respectively, and the two straight lines form a V shape with an opening facing one side of the outer circle of the rotor core, and the included angle of the V shape is a, 175°≤a<180°.

[0013] The application also provides an electric machine comprising the above-mentioned magnetic steel built-in electric machine rotor.

[0014] The application also provides an air conditioner comprising the above-mentioned electric machine.

[0015] The application provides a magnetic steel built-in electric machine rotor, an electric machine, and an air conditioner. Compared with the square magnetic steel in the prior art, the cylindrical magnetic steel can significantly reduce the centrifugal tensile stress of the rotor lamination and the magnetic steel at high speed, improve the maximum speed that the rotor can withstand, and reduce the vibration of the rotor at high speed. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 is a structural schematic diagram of a prior art electric machine rotor having a rectangular magnetic steel;

[0017] Figure 2 FIG. 2 is a structural schematic diagram (axial projection) of an electric machine rotor according to an embodiment of the application;

[0018] Figure 3 FIG. 3 is a structural schematic diagram of a magnetic steel slot and a magnetic steel in FIG. 2; Figure 2

[0019] Figure 4 FIG. 4 is a three-dimensional structural schematic diagram of the magnetic steel in FIG. 3; Figure 2

[0020] Figure 5 FIG. 5 is a stress comparison analysis schematic diagram of the rotor lamination of the electric machine rotor according to the embodiment of the application and the prior art electric machine rotor.​​

[0021] Figure 6 Stress comparison between the magnetic steel (cylinder) of the motor rotor of the embodiment of the present application and the magnetic steel (square) in the prior art.

[0022] The reference signs are shown as follows:

[0023] 1, rotor core; 11, magnetic steel slot; 111, positioning wall segment; 12, magnetic isolation gap; 2, magnetic steel; 21, positioning plane; 3, weight-reducing hole. DETAILED DESCRIPTION

[0024] For reference Figures 1 to 6 As shown in the figure, according to the embodiment of the present application, a magnetic steel built-in motor rotor is provided, which comprises a rotor core 1 formed by stacking rotor punching sheets, and the outer circumferential surface is a smooth cylindrical surface, and a welding groove can be opened. A plurality of magnetic steel slots 11 are constructed on the rotor core 1, and the plurality of magnetic steel slots 11 are arranged at intervals along the circumferential direction of the rotor core 1. Each magnetic steel slot 11 is provided with a magnetic steel 2. Any plane perpendicular to the axial direction of the rotor core 1 is a projection radial plane. The projection of the magnetic steel 2 and the magnetic steel slot 11 on the projection radial plane is a circular shape matching in size, that is, the magnetic steel 2 is a cylindrical magnetic steel, and the magnetic steel slot 11 is a circular magnetic steel slot. The magnetic steel in the technical solution is a cylindrical magnetic steel. Compared with the square magnetic steel in the prior art, the centrifugal tensile stress received by the rotor punching sheet and the magnetic steel at high speed can be significantly reduced without reducing the electromagnetic performance of the motor, the maximum speed that can be withstood by the rotor is improved, the rotor structure is compact, and the vibration during high-speed operation of the rotor is reduced.

[0025] It needs to be particularly pointed out that the magnetic steel is pressure-resistant but tensile-resistant. During high-speed rotation of the rotor, the main stress received by the magnetic steel is centrifugal tensile stress. The radial tensile stress of the cylindrical magnetic steel is smaller than that of the square magnetic steel, and the directions of the tangential tensile stress are different. The maximum stress value of the cylindrical magnetic steel is low at the same high speed. The cylindrical magnetic steel is less likely to be damaged than the square magnetic steel.

[0026] The number of the magnetic steel slots 11 on the rotor core 1 is, for example, twelve as shown in the figure, and the specific number is not limited to the number in the embodiment. It should be designed according to the actual functional requirements, but the ratio of the number of magnetic steel slots to the number of rotor poles must be 3:1. Figure 2

[0027] In some embodiments, the magnetic steel 2 and the magnetic steel slot 11 have a positioning structure, which effectively prevents the rotation of the circular magnetic steel 2 in the circular magnetic steel slot 11, thereby preventing misalignment during magnetization of the magnetic steel, and ensuring the consistency of the magnetization direction.

[0028] ​The aforementioned positioning structure can be, for example, a convex-concave fit structure, wherein the magnet 2 has a concave portion and the magnet groove 11 has a convex portion. In a preferred embodiment, on the projected radial plane, the outer peripheral wall of the magnet 2 has a positioning plane 21 extending along its length. The distance from any point on the positioning plane 21 to the geometric center of the magnet 2 is no greater than the radius of the magnet 2. The groove wall of the magnet groove 11 has a positioning wall segment 111 extending radially inward. A positioning point is formed between the positioning plane 21 and the cylindrical segment of the magnet 2. At least one end of the positioning wall segment 111 can abut against the positioning point. The positioning plane 21 and the positioning wall segment 111 together constitute the positioning structure. In this technical solution, the positioning plane 21 can be obtained by machining the outer peripheral wall of the magnet 2, which is convenient and easy to implement. The groove wall of the magnet groove 11 can form a curvature change through the positioning wall segment 111 extending radially inward. The rotational positioning of the magnet 2 is achieved by using the point of this curvature change to contact the positioning point, resulting in a simple structure. Furthermore, the positioning wall segment 111 has two sub-segments connected in a V-shape, and a magnetic isolation gap 12 is formed between the positioning wall segment 111 and the positioning plane 21 opposite to it. While realizing positioning, it can also play a role in magnetic isolation, thereby improving the utilization rate of the magnet.

[0029] In some embodiments, there are two positioning planes 21, which are symmetrical about the geometric center of the magnet 2. Correspondingly, there are two positioning wall segments 111, which are symmetrical about the geometric center of the magnet slot 11, thereby optimizing the magnetic field of the rotor.

[0030] As a specific embodiment, such as Figure 1 As shown, each magnetic pole of the rotor core 1 has four magnetic slots 11. The four magnetic slots 11 are symmetrically arranged about the d-axis of the magnetic pole, so that the magnetic field under each magnetic pole of the rotor core has sufficient strength. It has been verified that the electromagnetic performance of the motor is optimal at this time.

[0031] In some embodiments, the centers of the two magnetic slots 11 on both sides of the d-axis are respectively on a straight line, and the two straight lines form a V-shape with the opening facing the outer circle of the rotor core 1. The included angle of the V-shape is α, 175°≤α<180°, preferably 178°. This not only improves the magnetic focusing effect of the magnetic poles, but also further optimizes the structure of the motor rotor and further reduces the centrifugal tensile stress on the rotor laminations and magnets at high speeds.

[0032] The rotor core 1 also has evenly distributed weight-reduction holes 3, which can reduce the rotor inertia and bearing load, ensuring the rotational stability of the rotor. The rotor shaft is made of high-strength, non-magnetic material, which will not affect the performance of the motor and improve the overall stability of the permanent magnet synchronous motor operation.

[0033] See also Figure 5 andFigure 6 Under the same electromagnetic performance and rotational speed conditions, compared with the traditional square magnet-embedded rotor, the cylindrical magnet-embedded rotor of the present invention reduces the maximum stress of the laminations by 79.05 MPa and the maximum tensile stress of the magnets by 37.291 MPa. In other words, the technical solution of the present invention effectively reduces the maximum stress on the magnets and laminations at high speeds, improving the stability of the rotor under high-speed operation.

[0034] According to an embodiment of the present invention, an electric motor is also provided, including the above-described magnet-embedded motor rotor.

[0035] According to an embodiment of the present invention, an air conditioner is also provided, including the motor described above.

[0036] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A magnet-embedded motor rotor, characterized in that, The system includes a rotor core (1) on which a plurality of magnetic slots (11) are constructed. The plurality of magnetic slots (11) are arranged at intervals along the circumference of the rotor core (1). Each magnetic slot (11) is equipped with a magnet (2). Any plane perpendicular to the axial direction of the rotor core (1) is a projection radial plane. The projections of the magnet (2) and the magnetic slot (11) on the projection radial plane are circles of matching dimensions. There is a positioning structure between the magnet (2) and the magnetic slot (11). On the projection radial plane, the magnet (2) The outer peripheral wall has a positioning plane (21) extending along its length direction. The distance from any point on the positioning plane (21) to the geometric center of the magnet (2) is not greater than the radius of the magnet (2). The groove wall of the magnet groove (11) has a positioning wall segment (111) extending radially inward. The positioning plane (21) and the cylindrical segment of the magnet (2) form a positioning point. At least one end of the positioning wall segment (111) can abut against the positioning point. The positioning plane (21) and the positioning wall segment (111) together constitute the positioning structure.

2. The magnet-embedded motor rotor according to claim 1, characterized in that, The positioning wall segment (111) has two sub-segments connected in a V-shape, and a magnetic gap (12) is formed between the positioning wall segment (111) and the positioning plane (21) opposite to it.

3. The magnet-embedded motor rotor according to claim 1 or 2, characterized in that, There are two positioning planes (21), and the two positioning planes (21) are symmetrical about the geometric center of the magnet (2).

4. The magnet-embedded motor rotor according to claim 3, characterized in that, There are two positioning wall segments (111), and the two positioning wall segments (111) are symmetrical about the geometric center of the magnet groove (11).

5. The magnet-embedded motor rotor according to claim 1, characterized in that, The rotor core (1) has four magnetic slots (11) under each magnetic pole, and the four magnetic slots (11) are symmetrically arranged about the d-axis of the magnetic pole.

6. The magnet-embedded motor rotor according to claim 5, characterized in that, The centers of the two magnetic slots (11) on both sides of the d-axis are on a straight line, and the two straight lines form a V-shape with the opening facing the outer circle of the rotor core (1). The included angle of the V-shape is a, 175°≤a<180°.

7. An electric motor, characterized in that, The rotor of the motor with built-in magnets as described in any one of claims 1 to 6.

8. An air conditioner, characterized in that, Includes the motor described in claim 7.

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