Rotor core and permanent magnet motor

Abstract

The utility model provides a rotor core and a permanent magnet motor. The rotor core comprises N V-shaped magnetic pole grooves. The N magnetic pole grooves are formed in the axial end surface of the rotor iron core and are uniformly distributed in the circumferential direction of the rotor iron core; each magnetic pole groove is provided with a first magnetic isolation structure and two second magnetic isolation structures; the first magnetic isolation structure is arranged at the bottom of the V-shaped inner side of the magnetic pole groove and is communicated with the magnetic pole groove; the two second magnetism isolating structures are arranged at the two top ends of the inner side of the V shape of the magnetic pole groove respectively. According to the rotor iron core of the utility model, on the premise of not changing the existing magnetic pole grooves, the bottom and the two top sides of the V-shaped inner side of each magnetic pole groove are respectively provided with an air magnetic isolation structure, a magnetic circuit is optimized through the magnetic isolation structures at the positions, and magnetic isolation design is carried out on the parts, which are easy to demagnetize, of the permanent magnets, so that local accumulation of a demagnetizing magnetic field is avoided; the planned magnetic field trend is more reasonable, and local demagnetization of the edge parts of the permanent magnets contained in the magnetic pole grooves is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of compressors, in particular to a rotor core and a permanent magnet motor. Background Art

[0002] Currently, new energy air conditioning compressors are primarily driven by permanent magnet synchronous motors, whose rotors are typically excited by permanent magnets. Due to increasing cost requirements for compressor motors, the demagnetization resistance of permanent magnets has been reduced. Simultaneously, the need to meet design requirements for miniaturization and high power density has led to higher temperatures for permanent magnets, significantly increasing the risk of irreversible demagnetization. Furthermore, due to the uneven magnetic field, the edges of permanent magnets are susceptible to irreversible demagnetization.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0004] In response to the problems in the prior art, the purpose of the present invention is to provide a rotor core and a permanent magnet motor, in which the rotor core adds an air magnetic isolation structure to the magnetic pole slots corresponding to the permanent magnets that are prone to demagnetization, thereby avoiding local accumulation of the demagnetizing magnetic field and optimizing the magnetic circuit, thereby preventing local demagnetization from occurring at the edges of the permanent magnets placed in the magnetic pole slots.

[0005] A first aspect of the present invention provides a rotor core comprising N V-shaped magnetic pole slots each comprising two strip-shaped slots, where N is an even number;

[0006] The N magnetic pole slots are evenly distributed on the axial end surface of the rotor core and along the circumference of the rotor core;

[0007] Each of the magnetic pole slots is provided with a first magnetic isolation structure and two second magnetic isolation structures;

[0008] The first magnetic isolation structure is disposed at the inner bottom of the V-shaped magnetic pole slot and is in communication with the magnetic pole slot;

[0009] The two second magnetic isolation structures are respectively arranged at two top ends of the inner side of the V-shaped magnetic pole slot.

[0010] According to the first aspect of the present invention, the magnetic pole slots are symmetrical with respect to the magnetic pole center line.

[0011] According to the first aspect of the present invention, the two second magnetic isolation structures are symmetrical with respect to the center line of the magnetic pole.

[0012] According to the first aspect of the present invention, the first magnetic isolation structure is symmetrical about the magnetic pole center line, and the projection of the first magnetic isolation structure on the axial end surface of the rotor core is a quadrilateral; or

[0013] The first magnetic isolation structure is arranged on arc-shaped sides opposite to the inner bottom of the V-shaped magnetic pole slot.

[0014] According to the first aspect of the present invention, the projection of the first magnetic isolation structure on the axial end face of the rotor core is a quadrilateral, and the angle between the edge of the first magnetic isolation structure on the opposite side of the V-shaped inner bottom of the magnetic pole slot and the strip slot there is α, satisfying 100°<α<170°.

[0015] According to the first aspect of the present invention, the two strip-shaped grooves have the same structure, and the length of each strip-shaped groove is L1;

[0016] The effective length of the first magnetic isolation structure on the magnetic pole slot is L2, which satisfies 0.2 mm < L2 < 0.4*L1.

[0017] According to the first aspect of the present invention, the two strip-shaped grooves have the same structure, and the length of the strip-shaped groove is L1;

[0018] The projection of the second magnetic isolation structure on the axial end surface of the rotor core includes at least one straight side, and the straight side is parallel to the strip-shaped slot;

[0019] The projected length of the straight edge on the strip groove is L3, satisfying 0.2 mm < L3 < 0.35*L1.

[0020] According to the first aspect of the present invention, the projection of the second magnetic isolation structure on the axial end surface of the rotor core includes at least one straight side, and the straight side is parallel to the strip-shaped slot;

[0021] A vertical distance between the straight edge and the strip groove is L4, which satisfies 0.3 mm < L4 < 1.0 mm.

[0022] According to the first aspect of the present invention, the projection of the second magnetic isolation structure on the axial end surface of the rotor core includes at least one straight side, and the straight side is parallel to the strip-shaped slot;

[0023] An included angle β between the other side of the second magnetic isolation structure and the straight side satisfies 10°<β<80°.

[0024] A second aspect of the present invention provides a permanent magnet motor, comprising a rotor core and 2N permanent magnets, wherein two permanent magnets are disposed in magnetic pole slots of the rotor core.

[0025] Compared with the prior art, the rotor core of the utility model, without changing the existing magnetic pole slots, respectively sets air magnetic isolation structures at the bottom and two top sides of the inner side of the V-shaped magnetic pole slots. The magnetic isolation structures in these places optimize the magnetic circuit, and perform magnetic isolation design on the parts of the permanent magnets that are prone to demagnetization, thereby avoiding local accumulation of the demagnetizing magnetic field. The planned magnetic field direction is more reasonable, thereby preventing local demagnetization from occurring at the edge of the permanent magnets placed in the magnetic pole slots. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings herein are incorporated into and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the present invention will become more apparent. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same figure numbers in the figures represent the same or similar parts, and their repeated descriptions will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0027] Figure 1 A schematic structural diagram of the rotor core of the first embodiment of the present invention; and

[0028] Figure 2 Schematic diagram of the structure of the rotor core of the first embodiment after accommodating permanent magnets

[0029] Figure 3 This is a schematic diagram of the partial structure of the rotor core of the first embodiment of the present utility model;

[0030] Figure 4 This is a partial structural diagram of the rotor core of the second embodiment of the present utility model;

[0031] Figure 5 This is a schematic diagram of the partial structure of the rotor core of the third embodiment of the present utility model;

[0032] Figure 6 This is a schematic diagram of the partial structure of the rotor core of the fourth embodiment of the present utility model;

[0033] Figure 7 A schematic diagram of the partial structure of the rotor core of the fifth embodiment of the present invention; and

[0034] Figure 8 The demagnetization rate distribution diagrams of the permanent magnet motor of the existing structure and the permanent magnet motor of the present invention are obtained by using electromagnetic field analysis software. DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied to various different specific embodiments, and the various details of the present invention may be modified or altered based on different perspectives and application systems without departing from the spirit of the present invention. It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other, unless they conflict.

[0036] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. The present invention can be embodied in many different forms and is not limited to the embodiments described herein.

[0037] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and integrate different embodiments or examples, and features of different embodiments or examples, as long as they are not mutually inconsistent.

[0038] In order to clearly illustrate the present invention, components not related to the description are omitted, and the same or similar components throughout the specification are given the same reference numerals.

[0039] Throughout this specification, when a device is said to be "connected" to another device, this includes not only "direct connection" but also "indirect connection" with other elements interposed therebetween. Furthermore, when a device is said to "include" a certain component, unless otherwise stated, this does not exclude the inclusion of other components but rather implies that the device may include other components.

[0040] When a device is said to be "on" another device, it may be directly on the other device, but there may also be other devices between it. In contrast, when a device is said to be "directly on" another device, there are no other devices between it.

[0041] Although the terms first, second, etc. are used in some instances herein to represent various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, the first interface and the second interface, etc. are represented. Furthermore, as used in this article, the singular forms "one," "an," and "the" are intended to also include the plural forms, unless there is a contrary indication in the context. It should be further understood that the terms "comprise," "include," and "include" indicate the presence of features, steps, operations, elements, components, items, types, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, types, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B, or C" or "A, B, and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B, and C." Exceptions to this definition only occur when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0042] The technical terms used herein are intended only to refer to specific embodiments and are not intended to limit the present invention. The singular form used herein also includes the plural form, unless the statement explicitly indicates otherwise. The term "comprising" as used in this specification specifies specific features, regions, integers, steps, operations, elements, and / or components, and does not exclude the existence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0043] Although not defined otherwise, all terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art to which this invention belongs. Terms defined in commonly used dictionaries are to be interpreted as having meanings consistent with the relevant technical literature and current disclosures, and unless otherwise defined, they should not be overly interpreted as ideal or highly formalized meanings.

[0044] In order to overcome the above technical problems, the present invention provides a rotor core and a permanent magnet motor, wherein the rotor core includes N V-shaped magnetic pole slots including two strip-shaped slots; the N magnetic pole slots are evenly distributed on the axial end surface of the rotor core and along the circumference of the rotor core; each magnetic pole slot is provided with a first magnetic isolation structure and two second magnetic isolation structures; the first magnetic isolation structure is provided at the inner bottom of the V-shaped magnetic pole slot and is connected to the magnetic pole slot; the two second magnetic isolation structures are provided on both sides of the inner side of the V-shaped magnetic pole slot. Without changing the existing magnetic pole slots, the rotor core of the present invention provides air magnetic isolation structures at the bottom and two top sides of the inner side of the V-shaped magnetic pole slot, optimizes the magnetic circuit through the magnetic isolation structures in these places, performs magnetic isolation design on the parts of the permanent magnet that are easy to demagnetize, avoids local accumulation of demagnetizing magnetic field, plans a more reasonable magnetic field direction, and prevents local demagnetization of the edge parts of the permanent magnets placed in the magnetic pole slots.

[0045] The structure of the rotor core and the permanent magnet motor of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments are not intended to limit the scope of protection of the present invention.

[0046] Figure 1 This is a schematic structural diagram of the rotor core of the first embodiment of the present invention. Specifically, the rotor core includes N V-shaped magnetic pole slots 1, where N is an even number. The V-shaped magnetic pole slot 1 includes two interconnected strip slots. The N magnetic pole slots 1 are at the axial end of the rotor core and are evenly distributed along the circumference of the rotor core. In some embodiments, N can be 6 or 8, etc., that is, the rotor core has 6 (first embodiment) or 8 magnetic pole slots 1. For ease of processing, the permanent magnets are usually in the shape of bars that fit into the strip slots. Accordingly, 2N strip-shaped permanent magnets can be accommodated. Figure 2 FIG. 1 is a schematic structural diagram of the rotor core of the first embodiment after accommodating permanent magnets.

[0047] Each magnetic pole slot 1 is provided with a first magnetic isolation structure 2 and two second magnetic isolation structures 3, and the first magnetic isolation structure 2 and the two second magnetic isolation structures 3 are all air magnetic isolation slots. The first magnetic isolation structure 2 is provided at the bottom of the inner side of the V-shape of the magnetic pole slot 1 and is connected to the magnetic pole slot 1. The two second magnetic isolation structures 3 are provided at the two top ends of the inner side of the V-shape of the magnetic pole slot 1. It should be noted that the rotor core is actually formed by stamping and stacking a plurality of rotor punchings of the same structure. The rotor punchings can be silicon steel sheets or steel sheets. The center of the rotor core is also provided with a shaft hole and other structures, which are not described here.

[0048] For ease of explanation, the first embodiment uses the example of a magnetic pole slot 1 being symmetrical with respect to the magnetic pole centerline OO' to illustrate the positions of the first magnetic isolation structure 2 and the two second magnetic isolation structures 3 on the end faces of the rotor core. Here, the line connecting the bottom end of the V-shaped magnetic pole slot 1 and the center of the rotor core is used as the magnetic pole centerline OO'. That is, the two strip-shaped slots included in the magnetic pole slot 1 are symmetrical with respect to the magnetic pole centerline OO'.

[0049] Furthermore, the partial structural diagram of the rotor core of the first embodiment is shown in FIG. Figure 3 The first magnetic isolation structure 2 is symmetrical about the magnetic pole centerline OO', and its projection on the axial end face of the rotor core is a quadrilateral. The first magnetic isolation structure 2 is rhombus-shaped. That is, after two bar-shaped permanent magnets are installed in the magnetic pole slot 1, the two sides of the first magnetic isolation structure 2 on the opposite sides of the V-shaped inner bottom of the magnetic pole slot form a quadrilateral with the edges of the permanent magnets therein. When the two sides of the first magnetic isolation structure 2 on the opposite sides of the V-shaped inner bottom of the magnetic pole slot are respectively parallel to the edges of the two permanent magnets therein, the air isolation slot has a rhombus shape.

[0050] When the projection of the first magnetic isolation structure 2 on the axial end face of the rotor core is a quadrilateral, and the angle between the side of the first magnetic isolation structure 2 on the opposite side of the inner bottom of the V-shaped magnetic pole slot and the strip slot there is α, it can be seen that Figure 3 Preferably, 100°<α<170° is satisfied. In this case, the first magnetic isolation structure 2 can enhance the magnetic resistance at the inner bottom of the V-shaped magnetic pole slot 1, guide the magnetic field direction, and prevent the demagnetization magnetic field from impacting the weak parts of the permanent magnet, causing local irreversible demagnetization.

[0051] At the same time, when the structures of the two strip grooves are the same and the length of each strip groove is L1 (L1 is also the maximum length of the rectangular permanent magnet accommodated by the strip groove), preferably, the effective length of the first magnetic isolation structure on the magnetic pole slot 1 is L2, that is, the length of the intersection of the edge on the opposite side of the V-shaped inner bottom of the magnetic pole slot 1 and the magnetic pole slot 1 and the bottom end of the V-shape of the magnetic pole slot 1 is L2, satisfying 0.2mm<L2<0.4*L1.

[0052] The first magnetic isolation structure 2 may also be other structures. The first magnetic isolation structure is provided at the opposite sides of the V-shaped inner bottom of the magnetic pole slot and has an arc shape. The arc shape may be a part of a circle or an ellipse. Figure 4 and Figure 5Schematic diagrams of partial structures of the rotor core according to the second and third embodiments of the present invention, respectively. Unlike the first embodiment, in the second embodiment, the arcuate edge of the first magnetic isolation structure 2a, located on the side opposite the inner bottom of the V-shaped magnetic pole slot, curves away from the inner bottom of the V-shaped magnetic pole slot 1. That is, the center of the circle or the focus of the ellipse corresponding to the arcuate edge is on the side of the arcuate edge facing away from the V-shaped magnetic pole slot 1. In the third embodiment, the arcuate edge of the first magnetic isolation structure 2b, located on the side opposite the V-shaped magnetic pole slot 1, curves toward the inner bottom of the V-shaped magnetic pole slot 1. That is, the center of the circle or the focus of the ellipse corresponding to the arcuate edge is on the side of the arcuate edge facing the V-shaped magnetic pole slot 1. Similarly, in the above two embodiments, the length L2 between the intersection of the edge of the first magnetic isolation structure located on the side opposite the inner bottom of the V-shaped magnetic pole slot 1 and the bottom of the V-shaped magnetic pole slot 1 satisfies 0.2 mm < L2 < 0.4 * L1.

[0053] In the embodiment, the two second magnetic isolation structures 3 can be symmetrical with respect to the magnetic pole centerline OO', and the projection of the second magnetic isolation structure 3 on the axial end surface of the rotor core includes at least one straight side, which is parallel to the strip slot. For example, the second magnetic isolation structure 3 of the first embodiment is a triangle, one side of which is parallel to the strip slot. The second magnetic isolation structure can also be an irregular shape, such as Figure 6 The second magnetic isolation structure 3a and the Figure 7 In the second magnetic isolation structure 3b of the fifth embodiment, the other side of the second magnetic isolation structure 3a and the second magnetic isolation structure 3b is arc-shaped. The difference is that the directions or curvatures of the arcs are slightly different.

[0054] The utility model further defines the vertical distance L4 between the straight edge of the second magnetic isolation structure 3 and the strip groove of the magnetic pole slot 1 (see Figure 3 ), preferably, 0.3mm<L4<1.0mm. The projection length of the straight side of the second magnetic isolation structure 3 on the strip groove of the magnetic pole slot 1 is L3 (see Figure 3 ), satisfying 0.2mm<L3<0.35*L1, L1 is the length of the strip groove.

[0055] Furthermore, the angle β between the other side of the second magnetic isolation structure 3 (the line connecting the two ends of the other side) and the straight side is preferably 10°<β<80°. When the projection of the second magnetic isolation structure 3 at the axial end of the rotor core is a triangle, the angle β is the angle between the straight side and the other side; when the other side of the second magnetic isolation structure 3a is an arc, the angle β is the angle between the straight side and the line connecting the two ends of the arc-shaped side.

[0056] The utility model also provides a permanent magnet motor, including the rotor core and 2N permanent magnets. Two permanent magnets 9 are installed in the magnetic pole slots 1 of the rotor core to form a V-shaped magnetic pole structure. The central shaft hole of the rotor core can be fitted with the shaft by interference or key.

[0057] The permanent magnet motor with existing structure (not equipped with the first magnetic isolation structure and the second magnetic isolation structure of the present invention) obtained by simulation with electromagnetic field analysis software (JMAG Designer) Figure 8 Figure A in the figure) and the permanent magnet motor of the present invention (see Figure 8 Figure B in the figure shows the demagnetization rate distribution diagram. Table 1 shows the demagnetization rates of a conventional permanent magnet motor and a permanent magnet motor of the present invention. It can be seen that the demagnetization rate of the present permanent magnet motor, at 1.8%, is lower than the demagnetization rate of the conventional permanent magnet motor, at 3.2%. Without changing the permanent magnets, the present permanent magnet motor utilizes a redesigned rotor structure, optimized magnetic circuits, and magnetic isolation designed for areas prone to demagnetization of the permanent magnets, thereby avoiding localized accumulation of demagnetizing magnetic fields. Furthermore, the magnetic field direction is rationally planned to prevent localized demagnetization at the edges of the permanent magnets.

[0058]

[0059] Table 1

[0060] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

[0061] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A rotor core, characterized in that: It includes N V-shaped magnetic pole slots including two strip slots, where N is an even number; The N magnetic pole slots are evenly distributed on the axial end surface of the rotor core and along the circumference of the rotor core; Each of the magnetic pole slots is provided with a first magnetic isolation structure and two second magnetic isolation structures; The first magnetic isolation structure is disposed at the inner bottom of the V-shaped magnetic pole slot and is in communication with the magnetic pole slot; The two second magnetic isolation structures are respectively arranged at two top ends of the inner side of the V-shaped magnetic pole slot.

2. The rotor core according to claim 1, characterized in that The magnetic pole slots are symmetrical with respect to the magnetic pole center line.

3. The rotor core according to claim 1, wherein: The two second magnetic isolation structures are symmetrical with respect to the center line of the magnetic pole.

4. The rotor core according to claim 1, wherein: The first magnetic isolation structure is symmetrical about the magnetic pole center line, and the projection of the first magnetic isolation structure on the axial end surface of the rotor core is a quadrilateral; or The first magnetic isolation structure is arranged on arc-shaped sides opposite to the inner bottom of the V-shaped magnetic pole slot.

5. The rotor core according to claim 1, wherein: The projection of the first magnetic isolation structure on the axial end face of the rotor core is a quadrilateral, and the angle between the edge of the first magnetic isolation structure on the opposite side of the V-shaped inner bottom of the magnetic pole slot and the strip slot there is α, satisfying 100°<α<170°.

6. The rotor core according to claim 1, wherein: The two strip grooves have the same structure, and the length of each strip groove is L1; The effective length of the first magnetic isolation structure on the magnetic pole slot is L2, which satisfies 0.2 mm < L2 < 0.4*L1.

7. The rotor core according to claim 1, wherein: The two strip grooves have the same structure, and the length of the strip groove is L1; The projection of the second magnetic isolation structure on the axial end surface of the rotor core includes at least one straight side, and the straight side is parallel to the strip-shaped slot; The projected length of the straight edge on the strip groove is L3, which satisfies 0.2 mm < L3 < 0.35*L1.

8. The rotor core according to claim 1, wherein: The projection of the second magnetic isolation structure on the axial end surface of the rotor core includes at least one straight side, and the straight side is parallel to the strip-shaped slot; A vertical distance between the straight edge and the strip groove is L4, which satisfies 0.3 mm < L4 < 1.0 mm.

9. The rotor core according to claim 1, wherein: The projection of the second magnetic isolation structure on the axial end surface of the rotor core includes at least one straight side, and the straight side is parallel to the strip-shaped slot; An included angle β between the other side of the second magnetic isolation structure and the straight side satisfies 10°<β<80°.

10. A permanent magnet motor, characterized in that: The motor comprises a rotor core according to any one of claims 1 to 9 and 2N permanent magnets, wherein two permanent magnets are disposed in magnetic pole slots of the rotor core.

Images