Rotor core and permanent magnet motor

Abstract

The invention 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, on the premise that existing magnetic pole grooves are not changed, air magnetic isolation structures are arranged at the bottoms and the two top sides of the V-shaped inner sides of the magnetic pole grooves respectively, magnetic circuits are optimized through the magnetic isolation structures at the positions, magnetic isolation design is carried out on the portions, prone to demagnetization, of the permanent magnets, local accumulation of a demagnetizing magnetic field is avoided, and the demagnetizing effect is improved. 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 present invention relates to the technical field of compressors, and in particular to a rotor core and a permanent magnet motor. Background Art

[0002] At present, new energy air-conditioning compressors are mainly driven by permanent magnet synchronous motors, and permanent magnet synchronous motor rotors are usually excited by permanent magnets. As the cost requirements for compressor motors are getting higher and higher, the demagnetization resistance of permanent magnets has been reduced. At the same time, the design requirements of miniaturization and high power density need to be taken into account, resulting in higher temperatures of permanent magnets and a significantly increased risk of irreversible demagnetization. In addition, due to the uneven magnetic field, irreversible demagnetization is prone to occur at the edges of permanent magnets.

[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 the prior art known to those skilled in the art. Summary of the invention

[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 easily demagnetized, so as to avoid local accumulation of the demagnetizing magnetic field and optimize 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 including two strip 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 connected to 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 a 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 an arc-shaped side 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 grooves have the same structure, and the length of each strip 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 a straight side, and the straight side is parallel to the strip-shaped slot;

[0019] The projection length of the straight edge on the strip groove is L3, which satisfies 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 a straight side, and the straight side is parallel to the strip-shaped slot;

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

[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 a 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 as described above and 2N permanent magnets, wherein two permanent magnets are disposed in the magnetic pole slots of the rotor core.

[0025] Compared with the prior art, the rotor core of the present invention, without changing the existing magnetic pole slots, respectively arranges air magnetic isolation structures at the bottom and two top sides of the inner side of the V-shaped magnetic pole slots, optimizes the magnetic circuit through the magnetic isolation structures in these places, performs magnetic isolation design for the parts of the permanent magnet that are prone to demagnetization, avoids local accumulation of the demagnetizing magnetic field, and plans the magnetic field direction more reasonably, preventing local demagnetization from occurring at the edge of the permanent magnet placed in the magnetic pole slots. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings herein are incorporated into the specification 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 also 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 is a schematic structural diagram of a rotor core according to a first embodiment of the present invention; and

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

[0029] Figure 3 It is a schematic diagram of the partial structure of the rotor core of the first embodiment of the present invention;

[0030] Figure 4 is a schematic diagram of a partial structure of a rotor core according to a second embodiment of the present invention;

[0031] Figure 5 is a schematic diagram of a partial structure of a rotor core according to a third embodiment of the present invention;

[0032] Figure 6 is a schematic diagram of a partial structure of a rotor core according to a fourth embodiment of the present invention;

[0033] Figure 7 is a schematic diagram of a partial structure of a rotor core according to a fifth embodiment of the present invention; and

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

[0035] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in the present invention. The present invention can also be implemented or applied through other different specific embodiments, and the details in the present invention can also be modified or changed according to different viewpoints and application systems without departing from the spirit of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without 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 representation of the present invention, the reference terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics represented in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials or characteristics represented may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples represented in the present invention and the features of different embodiments or examples, unless they are contradictory.

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

[0039] Throughout the specification, when a device is said to be "connected" to another device, this includes not only the case of "direct connection" but also the case of "indirect connection" by placing other elements therebetween. In addition, when a device is said to "include" a certain component, unless otherwise stated, it does not exclude other components, but means that other components may be included.

[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 to represent various elements in some examples, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, the first interface and the second interface, etc. are represented. Moreover, as used in this article, the singular forms "one", "one" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising" and "including" indicate the existence of features, steps, operations, elements, components, projects, kinds, and / or groups, but do not exclude the existence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, 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". Only when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way, will there be an exception to this definition.

[0042] The technical terms used herein are only used to refer to specific embodiments and are not intended to limit the present invention. The singular form used herein also includes the plural form as long as the sentence does not clearly indicate the opposite meaning. The meaning of "including" used in the specification is to specify specific characteristics, regions, integers, steps, operations, elements and / or components, and does not exclude the existence or addition of other characteristics, regions, integers, steps, operations, elements and / or components.

[0043] Although not defined differently, all terms, including technical and scientific terms used herein, have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having meanings consistent with the content of relevant technical literature and current disclosures, and unless defined, shall not be overly interpreted as ideal or very formal 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 grooves; 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. The rotor core of the present invention, without changing the existing magnetic pole slots, respectively 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 for the parts of the permanent magnet that are easy to demagnetize, avoids the local accumulation of the demagnetizing magnetic field, and plans a more reasonable magnetic field direction, thereby preventing the edge parts of the permanent magnets placed in the magnetic pole slots from local demagnetization.

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

[0046] Figure 1 This is a schematic diagram of the structure 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 may 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 the strip slots. Accordingly, 2N bar-shaped permanent magnets can be accommodated. Figure 2 It 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 arranged at the inner bottom 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 arranged 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, and 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 will not be repeated here.

[0048] For the convenience of explanation, the first embodiment takes the symmetry of the magnetic pole slot 1 relative to the magnetic pole center line OO' as an example to explain the positions of the first magnetic isolation structure 2 and the two second magnetic isolation structures 3 on the end surface of the rotor core of the present invention. Here, the line connecting the bottom end of the V-shaped magnetic pole slot 1 and the center of the rotor core is taken as the magnetic pole center line OO', that is, the two strip grooves included in the magnetic pole slot 1 are symmetric relative to the magnetic pole center line OO'.

[0049] Further, the partial structural diagram of the rotor core of the first embodiment is shown in Figure 3 , the first magnetic isolation structure 2 is symmetrical about the magnetic pole center line OO', and the projection of the first magnetic isolation structure 2 on the axial end surface of the rotor core is a quadrilateral. The first magnetic isolation structure 2 is in a rhombus shape, that is, after installing two bar-shaped permanent magnets in the magnetic pole slot 1, the two sides of the first magnetic isolation structure 2 arranged on the opposite sides of the inner bottom of the V-shaped magnetic pole slot form a quadrilateral with the edge of the permanent magnet there, and when the two sides of the first magnetic isolation structure 2 arranged on the opposite sides of the inner bottom of the V-shaped magnetic pole slot are respectively parallel to the edges of the two permanent magnets there, the air isolation slot is in a rhombus shape.

[0050] When the projection of the first magnetic isolation structure 2 on the axial end surface of the rotor core is a quadrilateral, and the angle between the side of the first magnetic isolation structure 2 arranged 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. At this time, the first magnetic isolation structure 2 can enhance the magnetic resistance of 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 and 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 pole slot 1 is L2, that is, the length of the intersection of the edge on the opposite side of the inner bottom of the V-shape of the pole slot 1 and the pole slot 1 and the bottom end of the V-shape of the 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 arranged on the opposite side of the V-shaped inner bottom of the magnetic pole slot and the side is arc-shaped. The arc shape may be a part of a circle or an ellipse. Figure 4 and Figure 5The partial structural schematic diagrams of the rotor core of the second embodiment and the third embodiment of the present invention are respectively different from the first embodiment in that the arc-shaped edge of the first magnetic isolation structure 2a of the second embodiment is arranged on the opposite side of the V-shaped inner bottom of the magnetic pole slot, and the bending direction of the arc-shaped edge is away from the V-shaped inner bottom of the magnetic pole slot 1, that is, the center of the circle corresponding to the arc-shaped edge or the focus of the ellipse is on the side of the arc-shaped edge away from the V-shaped bottom of the magnetic pole slot 1. The bending direction of the arc-shaped edge of the first magnetic isolation structure 2b of the third embodiment is toward the V-shaped inner bottom of the magnetic pole slot 1, that is, the center of the circle corresponding to the arc-shaped edge or the focus of the ellipse is on the side of the arc-shaped edge facing the V-shaped bottom of the magnetic pole slot 1. Similarly, in the above two embodiments, the length L2 of the intersection of the edge of the first magnetic isolation structure arranged on the opposite side of the V-shaped inner bottom of the magnetic pole slot 1 and the magnetic pole slot 1 and the V-shaped bottom of the magnetic pole slot 1 satisfies 0.2mm<L2<0.4*L1.

[0053] In the embodiment, the two second magnetic isolation structures 3 can be symmetrical with respect to the magnetic pole center line 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, and the straight side is parallel to the strip groove. For example, the second magnetic isolation structure 3 of the first embodiment is a triangle, one side of which is parallel to the strip groove. The second magnetic isolation structure can also be an irregular shape, such as Figure 6 The second magnetic isolation structure 3a and 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, but the difference is that the directions or curvatures of the arcs are slightly different.

[0054] The present invention further defines a vertical distance L4 between the straight edge of the second magnetic isolation structure 3 and the strip groove of the magnetic pole groove 1 (see Figure 3 ), preferably, 0.3mm<L4<1.0mm. The projection length of the straight edge of the second magnetic isolation structure 3 on the strip groove of the magnetic pole groove 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 present invention also provides a permanent magnet motor, comprising the rotor core and 2N permanent magnets, wherein two permanent magnets 9 are installed in the magnetic pole slot 1 of the rotor core to form a V-shaped magnetic pole structure, and 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 (the motor without the first magnetic isolation structure and the second magnetic isolation structure of the present invention, see Figure 8 A in FIG) and the permanent magnet motor of the present invention (see Figure 8 The demagnetization rate distribution diagram of the permanent magnet motor of the prior art and the permanent magnet motor of the present invention is shown in Figure B, and Table 1 shows the demagnetization rates of the permanent magnet motor of the prior art and the permanent magnet motor of the present invention. It can be seen that the demagnetization rate of the permanent magnet motor of the present invention is 1.8%, which is lower than the demagnetization rate of the permanent magnet motor of the prior art, 3.2%. The permanent magnet motor of the present invention, without changing the permanent magnet, designs the rotor structure, optimizes the magnetic circuit, performs magnetic isolation design on the part of the permanent magnet that is easy to demagnetize, avoids the local accumulation of the demagnetization magnetic field, reasonably plans the direction of the magnetic field, and prevents the local demagnetization of the edge of the permanent magnet.

[0058]

[0059] Table 1

[0060] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

[0061] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A rotor core, It is 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 connected to 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, It is 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, It is characterized in that 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, It is characterized in that 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, It is characterized in that 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, It is characterized in that 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, It is characterized in that 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 a straight side, and the straight side is parallel to the strip-shaped slot; The projection 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, It is characterized in that The projection of the second magnetic isolation structure on the axial end surface of the rotor core includes at least a 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, It is characterized in that The projection of the second magnetic isolation structure on the axial end surface of the rotor core includes at least a straight side, and the straight side is parallel to the strip-shaped slot; An angle β between another side of the second magnetic isolation structure and the straight side satisfies 10°<β<80°.

10. A permanent magnet motor, It is characterized in that The motor comprises a rotor core as claimed in 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