Rotor for permanent magnet synchronous motor and permanent magnet synchronous motor

Abstract

The utility model relates to a rotor for a permanent magnet synchronous motor, and the rotor comprises a first permanent magnet which is constructed to be a hollow cylinder and is integrally formed, and a plurality of interval grooves are arranged in the first permanent magnet along the circumferential direction. The first permanent magnet is divided into a plurality of first permanent magnet sub-parts by the spacing grooves; the second permanent magnets are arranged in the interval grooves; wherein a plurality of positioning holes are formed in the first permanent magnet in the circumferential direction, the positioning holes are formed between the interval grooves and the inner circumference of the first permanent magnet, and the positioning holes penetrate through the first permanent magnet in the longitudinal direction; wherein the plurality of first permanent magnet sub-parts form alternating magnetic poles, the positioning holes are designed in a way that positioning rods penetrate through the positioning holes to connect the plurality of rotors in series in the longitudinal direction, and the same magnetic poles of the plurality of rotors are aligned in the longitudinal direction. The utility model also relates to a permanent magnet synchronous motor comprising the rotor.

Description

Technical Field

[0001] The utility model relates to a rotor for a permanent magnet synchronous motor and the permanent magnet synchronous motor. Background Art

[0002] The rotor currently used for permanent magnet synchronous motors is composed of a magnetizer and a permanent magnet, wherein the magnetizer is formed by stacking stamped silicon steel sheets, and the permanent magnet is embedded in the magnetizer. The silicon steel sheets constituting the magnetizer can be, for example, non-oriented silicon steel sheets or oriented silicon steel sheets. The difference in magnetic permeability or magnetic permeability in each direction of the non-oriented silicon steel sheet is very small, that is, there is no directional difference, while the magnetic permeability or magnetic permeability of the oriented silicon steel sheet in different directions is different, that is, it has excellent magnetic permeability in a specific direction, and poor magnetic permeability in other directions.

[0003] When the rotor magnetizer is made of non-oriented silicon steel sheets, the magnetization depth of the magnetizer is not deep enough. When oriented silicon steel sheets are used, the magnetization of the magnetizer will be uneven due to the specific orientation of the silicon steel sheets. In addition, the magnetizer itself is non-magnetic, which results in a waste of rotor space for the magnetizer, making the rotor space not fully utilized and unable to maximize the magnetic flux of the rotor. Utility Model Content

[0004] The utility model provides a rotor for a permanent magnet synchronous motor, which can be simply connected in series in a longitudinal direction to form a rotor with a larger aspect ratio.

[0005] The utility model proposes a rotor for a permanent magnet synchronous motor, the rotor comprising: a first permanent magnet, the first permanent magnet being constructed as a hollow cylinder and being integrally formed, a plurality of spacing grooves being arranged inside the first permanent magnet along a circumferential direction, the first permanent magnet being divided into a plurality of first permanent magnet sub-portions by the spacing grooves; a second permanent magnet, the second permanent magnet being arranged in the spacing grooves; wherein a plurality of positioning holes are arranged inside the first permanent magnet along a circumferential direction, the positioning holes being arranged between the spacing grooves and the inner circumference of the first permanent magnet, the positioning holes penetrating the first permanent magnet in a longitudinal direction; wherein the plurality of first permanent magnet sub-portions form alternating magnetic poles, the positioning holes being designed such that a positioning rod passes through the positioning holes, a plurality of the rotors are connected in series in a longitudinal direction, and the same magnetic poles of the plurality of the rotors are aligned in the longitudinal direction.

[0006] In an embodiment of the present invention, the number of the positioning holes is equal to the number of pole pairs of the rotor, and the positioning holes are arranged on the midline of two magnetic poles from the N pole to the S pole in a clockwise direction along the circumferential direction.

[0007] In an embodiment of the present invention, the rotor has a plastic-encapsulated shell, and the plastic-encapsulated shell surrounds two end surfaces of the rotor.

[0008] In an embodiment of the present invention, the cross section of the spacing groove is configured as a trapezoid, and the lower base of the trapezoidal cross section is close to the inner circumference of the first permanent magnet.

[0009] In an embodiment of the present invention, a positioning portion is provided in the spacing groove, and the positioning portion is configured as a protrusion and is arranged in the spacing groove at one side close to the inner circumference of the first permanent magnet.

[0010] In an embodiment of the present invention, an air groove is provided between the second permanent magnet arranged in the spacing groove and the first permanent magnet on a side facing the inner circumference of the first permanent magnet.

[0011] In an embodiment of the present invention, the outer circumferential surface of the first permanent magnet is a closed surface.

[0012] In an embodiment of the present invention, the spacing groove penetrates the first permanent magnet along the longitudinal direction of the first permanent magnet.

[0013] In an embodiment of the present invention, the material of the first permanent magnet is plastic ferrite.

[0014] In an embodiment according to the utility model, the spacing groove is used to accommodate a magnetic field application device during the orientation and magnetization process, so that the first permanent magnet obtains permanent magnetism; wherein the first permanent magnet sub-portion has a magnetic field direction extending along the radial direction of the first permanent magnet, and the first permanent magnet sub-portions on both sides of the spacing groove have opposite magnetic field directions respectively; wherein the magnetic field direction of the second permanent magnet extends along the circumferential direction of the first permanent magnet; and wherein the magnetic field of the second permanent magnet in the spacing groove together with the magnetic field of the first permanent magnet on both sides of the spacing groove form a continuous magnetic circuit with the shortest path.

[0015] The utility model also relates to a permanent magnet synchronous motor, which comprises the rotor described in the above embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the embodiment of the utility model, the following is a brief introduction to the drawings required for the description of the embodiment. Obviously, the drawings described below are only some exemplary embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1An exploded perspective view of a rotor for a permanent magnet synchronous motor according to an embodiment of the utility model is shown.

[0018] Figure 2 A cross-sectional view of a first permanent magnet of a rotor according to an embodiment of the present utility model is shown,

[0019] Figure 3 A perspective view showing rotors connected in series in the longitudinal direction according to an embodiment of the utility model is shown.

[0020] Figure 4 A perspective cross-sectional view showing rotors connected in series in the longitudinal direction according to an embodiment of the utility model, and

[0021] Figure 5 A schematic diagram of a magnetic circuit of a permanent magnet synchronous motor including a rotor according to an embodiment of the utility model is shown. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the technical solution of the utility model clearer, the technical solution of the embodiment of the utility model will be clearly and completely described in conjunction with the drawings of the specific embodiments of the utility model. The same figure marks in the drawings represent the same parts. It should be noted that the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the described embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] Compared with the embodiments shown in the drawings, feasible implementations within the scope of protection of the present invention may have fewer components, other components not shown in the drawings, different components, differently arranged components, or differently connected components, etc. In addition, two or more components in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as multiple separate components.

[0024] Figure 1An exploded view of a rotor 100 for a permanent magnet synchronous motor according to an embodiment of the utility model is schematically shown. The rotor 100 includes a first permanent magnet 110 and a second permanent magnet 120. The first permanent magnet 110 is configured as a hollow cylinder. In an embodiment according to the utility model, the outer circumferential surface of the first permanent magnet 110 can be, for example, a closed surface, so as to obtain better structural strength. A plurality of spacing grooves 130 are arranged in the circumferential direction inside the first permanent magnet 110, and the first permanent magnet 110 is divided into a plurality of first permanent magnet sub-portions 111 by the spacing grooves 130. In an embodiment according to the utility model, the spacing grooves 130 penetrate the first permanent magnet 110 in the axial direction. A plurality of second permanent magnets 120 are respectively arranged in the spacing grooves 130, and in particular are inserted into the spacing grooves 130. In the utility model, the rotor 100 has alternating N poles and S poles. These magnetic poles are formed at the first permanent magnet sub-portion 111, such as Figure 1 The specific magnetic circuit and magnetic field direction will be described in detail later.

[0025] During the manufacturing process of the first permanent magnet, the space occupied by the spacing groove is used to place an orientation tool to apply a magnetic field, so that the first permanent magnet sub-portions on both sides of the spacing groove can obtain a deeper orientation depth, in preparation for the subsequent deeper magnetization depth.

[0026] In the prior art, the permanent magnets in the rotor are usually made of high magnetic energy product materials, such as neodymium iron boron. The cost of high magnetic energy material is high and the magnetization depth is limited. Permanent magnets made of high magnetic energy product materials are usually arranged on the magnetizer in an embedded manner or surface-mounted manner. The volume of permanent magnets made of high magnetic energy product materials and rotors with such permanent magnets is usually small. In this case, it is necessary to increase the stator or increase the stator coil to increase the power of the synchronous motor. In contrast, in the utility model, the first permanent magnet can be made of a material with low magnetic energy product, such as a plastic magnetic material. Plastic magnetic materials are relatively cheap. The deep orientation and magnetization of the first permanent magnet can be achieved through the spacing grooves in the first permanent magnet. Based on these two points, the first permanent magnet can be constructed as large as possible, and the rotor with such a first permanent magnet can provide a stronger magnetic field and more magnetic flux. The rotor according to the utility model can achieve the performance of a rotor made of a high magnetic energy product material.

[0027] In the prior art, the rotor of a permanent magnet synchronous motor is composed of a magnetizer and a permanent magnet. The permanent magnet can be attached to the surface of the magnetizer to form a surface-mounted rotor, or the permanent magnet can be inserted into the magnetizer to form an embedded rotor. This type of magnetizer is formed by stamping and stacking silicon steel sheets, so it cannot be manufactured by an integrated molding process.

[0028] Compared with the prior art, a first permanent magnet is used in the rotor according to the utility model instead of a magnetizer. The first permanent magnet according to the utility model is made of plastic magnetic material by injection molding, and can be very conveniently prepared by an integrated molding process. Compared with the process of stamping and stacking silicon steel sheets, the integrated molding process of the first permanent magnet has a simple process, high efficiency, high precision, and low cost. In addition, the first permanent magnet composed of plastic magnetic material can provide magnetic force itself, and its magnetic permeability is much higher than that of the silicon steel sheet magnetizer. Therefore, the magnetization depth of the rotor according to the utility model is deeper, the material utilization rate is higher, and the power density is greater.

[0029] In the present invention, the one-piece molding process should be understood as the molding process of the entire part in one mold at one time. Compared with the traditional step-by-step manufacturing process, one-piece molding greatly reduces the cost of part production, faster production speed, and can produce various parts, products, tools, etc. in a very short time. The process flow of one-piece molding is relatively simple, and the required contours, holes, surface treatment, etc. can be completed in one mold, which can greatly reduce production time and cost, and at the same time improve the production accuracy and repeatability of parts. In the traditional processing method, it is necessary to prepare the mold and template first, and then the parts are processed step by step. The one-piece molding process does not require additional preparation of templates, etc., and it can be truly completed in one step, and the processing efficiency and speed are greatly improved. In addition, the mold designed by the one-piece molding process is usually produced in one time, so the speed is very fast, and large-scale production can be completed quickly, which can meet market demand more quickly. The one-piece molding process can not only meet the needs of the traditional manufacturing field, but also can be applied to some high-tech fields, such as generators, car wash manufacturing, medical equipment, etc. In these fields, the one-piece molding process can create more precise and higher-quality parts and products.

[0030] The first permanent magnet formed in one piece is made of magnetic material, and preferably a magnetic material with low magnetic resistance and good magnetic conductivity can be selected. In an embodiment according to the utility model, the first permanent magnet 110 can be made of plastic ferrite, for example, by one-time molding by injection molding. Plastic ferrite has low magnetic resistance, good magnetic conductivity, deep magnetization depth, and is suitable for one-piece molding and industrial production. In an embodiment according to the utility model, plastic ferrite can be a mixture of nylon and ferrite, for example. The first permanent magnet made of plastic ferrite accommodates the second permanent magnet, so the rotor space is fully utilized, so that the rotor can provide a larger magnetic flux without changing the volume. Plastic ferrite has a smaller density than silicon steel material, which leads to a reduction in the weight of the rotor made of plastic ferrite, so the power and energy efficiency of the motor can be improved. In addition, plastic ferrite has a higher resistivity than silicon steel material, so the rotor made of plastic ferrite can effectively reduce eddy current loss compared to the rotor made of silicon steel material.

[0031] Figure 2 A cross-sectional view of the first permanent magnet 110 of the rotor 100 according to an embodiment of the utility model is shown. In the utility model, a plurality of positioning holes 210 are arranged along the circumferential direction inside the first permanent magnet 110. These positioning holes 210 are arranged between the spacing groove 130 and the inner circumference of the first permanent magnet 110. For example, the positioning holes 210 may be close to the rotor sleeve 220 of the rotor. These positioning holes 210 penetrate the first permanent magnet 110 in the longitudinal direction. The positioning holes 110 are designed so that the positioning rod passes through the positioning holes 110, and the multiple rotors 100 are connected in series in the longitudinal direction, and the same magnetic poles of the multiple rotors 100 are aligned in the longitudinal direction. Therefore, the positioning holes 110 can also be called series holes. This point is in Figure 3 and Figure 4 is shown in more detail.

[0032] In practical applications, permanent magnet synchronous motors usually have standard sizes to facilitate application in different devices and scenarios. This standard size is reflected in the specific radius size or specific shaft center height of the permanent magnet synchronous motor as a whole. When the overall size of the motor has been determined, in order to increase the power of the motor, the diameter of the rotor can be increased or the length of the rotor can be increased. However, when the orientation and magnetization depth of the first permanent magnet of the rotor remain unchanged, increasing the rotor diameter will reduce the utilization rate of the magnetic material. If the orientation and magnetization depth are increased, the rotor processing process will become complicated. In contrast, increasing the length of the rotor, the utilization rate of the magnetic material remains unchanged, and the process of increasing the length of the rotor is relatively simple. According to the utility model, the rotor can be connected in series in the longitudinal direction. The rotor after series connection has a higher aspect ratio as a whole, and the length of the rotor as a whole can be adjusted according to the number of rotors connected in series. In addition, the positioning hole is arranged between the spacing slot and the inner circumference of the first permanent magnet, and the positioning hole can avoid the rotor magnetic circuit, so as not to affect the performance of the rotor and the motor.

[0033] Figure 3 FIG. 1 shows a perspective view of rotors 310 connected in series in the longitudinal direction according to an embodiment of the present invention. Figure 4 A perspective cross-sectional view thereof is shown. Figure 3 and Figure 4Two rotors 310 connected in series in the longitudinal direction are shown. In other embodiments, more rotors may be connected in series. Compared to a single rotor, the series connection of multiple rotors 310 doubles the length of the rotor as a whole 300. The two rotors 310 have the same structure according to the utility model. The inside of the positioning hole 210 is smooth, which facilitates the pressing and extraction of the positioning rod 320 into and out of the positioning hole 210. After the multiple rotors 310 are connected in series using the positioning rod 320, the rotor as a whole 300 is pressed into the rotor shaft, and then the positioning rod 320 is extracted. Because the rotor as a whole 300 and the rotor shaft are tightly matched, the relative positions between the multiple rotors 310 will not change after the positioning rod 320 is extracted.

[0034] In the embodiment of the present invention, the number of the positioning holes 210 may be equal to the number of pole pairs of the rotor 100 or 310. Figure 2 For explanation. Figure 2 In the illustrated embodiment, the rotor 100 or the first permanent magnet 110 exemplarily has 10 poles, and the number of pole pairs is 5. Five positioning holes 210 are provided in the first permanent magnet 110. The five positioning holes 210 are arranged between the spacing slots 130 and the inner circumference of the first permanent magnet 110, and are arranged at intervals. In other words, the positioning holes 210 are arranged between the first, third, fifth, seventh and ninth spacing slots and the inner circumference of the first permanent magnet 110. In addition, the positioning holes 210 are preferably arranged at the dividing line between adjacent magnetic poles, that is, on the center line between adjacent magnetic poles. In general, the positioning holes 210 are arranged on the center line of the two magnetic poles from the N pole to the S pole in the clockwise direction along the circumferential direction. Figure 2 In the illustrated embodiment, in the clockwise direction of the circumferential direction, the positioning holes 210 are arranged only on the midline of the two magnetic poles from the N pole to the S pole, and no positioning holes 210 are arranged on the midline of the two magnetic poles from the S pole to the N pole.

[0035] The number of positioning holes is preferably equal to the number of pole pairs, and the positioning holes are evenly arranged in the first permanent magnet in the circumferential direction. After aligning the positioning holes of multiple rotors, the same magnetic poles of each rotor are exactly aligned in the longitudinal direction, without considering whether the order of the positioning holes corresponds one to one. This arrangement of positioning holes can quickly and easily achieve the alignment of the magnetic poles of multiple rotors, improve the efficiency of rotor series connection and assembly, and on the other hand, the uniform distribution of the positioning holes will not affect the dynamic balance performance of the rotor.

[0036] If the positioning holes are evenly arranged in the first permanent magnet in the circumferential direction, but the number of positioning holes is not equal to the number of pole pairs, for example, the number of pole pairs is 5 and the number of positioning holes is 4 or 6, then there is no fixed correspondence between the positions of the positioning holes and the positions of the magnetic poles. When multiple rotors are connected in series, the positioning holes need to be aligned one by one according to the order of the positioning holes, that is, the first positioning holes of each rotor are aligned, the second positioning holes of each rotor are aligned respectively... and so on. Only in this way can the same magnetic poles between each rotor be aligned. If the order of the positioning holes is misaligned, the same magnetic poles of each rotor will also be misaligned. This arrangement of positioning holes increases the complexity of the rotor series connection and greatly affects production efficiency.

[0037] exist Figure 3 and Figure 4 The figure also shows the plastic-encapsulated shell 330 of the rotor 310. The plastic-encapsulated shell 330 surrounds the two end faces of the rotor 310. The upper and lower end faces of the rotor 310 can be coated with a polymer material to form the plastic-encapsulated shell 330, for example. The plastic-encapsulated shell 330 can prevent the second permanent magnet 120 from falling off from the spacing groove 130 of the first permanent magnet 110, and the plastic-encapsulated shell 330 can provide additional mechanical strength for the rotor, so that the rotor can adapt to a higher rotation speed. In addition, when multiple rotors 310 are connected in series, the plastic-encapsulated shell 330 forms a plastic-encapsulated layer on the end face of the rotor 310, which can act as a magnetic isolation plate to avoid magnetic leakage.

[0038] During the plastic encapsulation process, the plastic encapsulation material is located at the two axial end faces of the rotor and the middle through hole and groove (not shown). The plastic encapsulation material is placed in a preheating machine for preheating, and the rotor is placed in a mold. The plastic encapsulation process is performed according to pre-set parameters. After the plastic encapsulation is completed, the rotor is inspected to confirm that the plastic encapsulation material completely covers the two end faces of the rotor, and that there are no internal voids and stratifications in the plastic encapsulation layer, and that the appearance of the plastic encapsulation body is defect-free.

[0039] In an embodiment according to the present utility model, Figure 1 and Figure 2 As shown, the cross-sections of the spacing grooves 130 and the second permanent magnets 120 can be configured as trapezoids, for example, and the lower base of the trapezoidal cross-section is close to the inner circumference of the cross-section of the first permanent magnet 110, while the upper base of the trapezoidal cross-section is close to the outer circumference of the cross-section of the first permanent magnet 110. The spacing grooves 130 and the second permanent magnets 120 configured with trapezoidal cross-sections can allow the magnetic field to pass through the first permanent magnet 110 more, thereby reducing magnetic leakage.

[0040] In an embodiment according to the present utility model, Figure 2As shown in , for example, a positioning portion 231 can be provided in the spacing groove 130, and the positioning portion 231 is used to fix the second permanent magnet 120 in the spacing groove 130. In an embodiment according to the utility model, the positioning portion 231 is arranged in the spacing groove 130 on one side of the inner circumference of the cross section of the first permanent magnet 110 close to the first permanent magnet 110. In an embodiment according to the utility model, the positioning portion 231 is configured as a protrusion for abutting against the second permanent magnet, and the protrusion can be configured as a triangle or a semicircle, for example. The size of the spacing groove 130 of the first permanent magnet 110 is larger than that of the second permanent magnet 120, so that the second permanent magnet 120 can be more easily inserted into the spacing groove 130, and therefore, a positioning portion 231 needs to be provided to fix the second permanent magnet 120 in the spacing groove 130.

[0041] In an embodiment according to the present utility model, Figure 2 As shown in the figure, the second permanent magnet 120 arranged in the spacing slot 130 is provided with an air slot 232 between the first permanent magnet 110 and the side facing the inner circumference of the first permanent magnet 110. The air slot 232 can be formed naturally, for example, when the positioning portion 231 is provided, that is, after the second permanent magnet 120 is inserted into the spacing slot 130, a gap is formed between the second permanent magnet 120 and the first permanent magnet 110 due to the larger size of the spacing slot. Since air has a very low magnetic permeability, the air slot 232 can reduce magnetic leakage. The rotor magnetic circuit will not extend into the rotor through the air slot 232.

[0042] Figure 5 A schematic diagram of the magnetic circuit of a permanent magnet synchronous motor 500 including a rotor 510 according to an embodiment of the utility model is shown. The permanent magnet synchronous motor 500 includes a rotor 510 and a stator 620 according to an embodiment of the utility model. The rotor 510 has been magnetized. During the magnetization process, that is, during the orientation and magnetization process, a magnetic field application device can be arranged around the rotor and in the spacing slots, for example, so that the first permanent magnet obtains permanent magnetism. The rotor 510 has alternating N poles and S poles. Inside the rotor 510, the first permanent magnet sub-portion corresponding to the S pole has a magnetic field direction extending radially inward, and the first permanent magnet sub-portion corresponding to the N pole has a magnetic field direction extending radially outward. Between adjacent S poles and N poles, the magnetic field starts from the S pole, transitions through the second permanent magnet and reaches the N pole in the shortest path, and the magnetic field in the second permanent magnet extends in the circumferential direction. Figure 5510 , the second permanent magnets 511, 512 and 513 are shown. The magnetic field direction of the second permanent magnet 512 extends along the circumferential direction of the rotor 510 and is opposite to the magnetic field directions of the adjacent second permanent magnets 511 and 513. On both sides of the second permanent magnet 511 are the first permanent magnet sub-portions 521 and 524, on both sides of the second permanent magnet 512 are the first permanent magnet sub-portions 521 and 522, and on both sides of the second permanent magnet 513 are the first permanent magnet sub-portions 522 and 523.

[0043] For example, the magnetic field starts from the first permanent magnet sub-portion 521 of the rotor 510, and the magnetic field extends outward in the radial direction in the first permanent magnet sub-portion 521. The magnetic field passes through the air gap and the slot gap between the rotor 510 and the stator 620 to reach the tooth shoe of the stator 620. Specifically, most of the magnetic field passes through the air gap to reach the tooth shoe 6121, and a small part of the magnetic field passes through the air gap to reach the tooth shoe 6221 and passes through the slot 6121 to reach the tooth shoe 6211. Then the magnetic field extends outward in the radial direction in the corresponding tooth portion 621 and reaches the stator yoke 630. The stator yoke 630 is formed at the outermost periphery of the stator 620, which is a hollow cylinder. The stator yoke 630 is used to guide the magnetic field or magnetic flux to pass through and form a closed magnetic circuit. After reaching the stator yoke 630, a part of the magnetic field is bent and extends in the clockwise direction to reach the tooth portion 622. This part of the magnetic field extends radially inward in the tooth portion 622 to the tooth shoe 6221, and passes through the air gap and the slot 6131 of the slot portion 613 to the first permanent magnet sub-portion 522 of the rotor 510. In other words, the above part of the magnetic field extends in the clockwise direction around the slot portion 612. Another part of the magnetic field is bent and extends in the counterclockwise direction to the tooth portion 623. This part of the magnetic field extends radially inward in the tooth portion 623 to the tooth shoe 6231, and passes through the air gap to the first permanent magnet sub-portion 524 of the rotor 510. In other words, the above another part of the magnetic field extends in the counterclockwise direction around the slot portion 611. With reference to the magnetic field direction and magnetic circuit extension of the stator 620 around the slot portions 612 and 611, the magnetic field direction and magnetic circuit extension of the stator 620 around other slot portions can be known by comparison. The magnetic circuit of the stator 620 and the magnetic circuit of the rotor 510 together constitute a closed magnetic circuit. The rotating magnetic field of the stator 620 interacts with the magnetic field of the rotor 510 and generates torque on the rotor 510 and causes the rotor 510 to rotate at a synchronous speed.

[0044] from Figure 5As can be seen in the figure, the trapezoidal cross-section of the spacing slot or the second permanent magnet 511, 512 and 513 makes each first permanent magnet sub-portion 521, 522, 523 and 524 narrower as it approaches the inner circumference, so that the magnetic field in each first permanent magnet sub-portion 521, 522, 523 and 524 passes more through the second permanent magnet 511, 512 and 513, and passes less through the positioning hole 210, the rotor sleeve 220 and the rotor shaft, thereby reducing magnetic leakage. In addition, the air slot 232 can further prevent the magnetic field in each first permanent magnet sub-portion 521, 522, 523 and 524 from passing through the positioning hole 210, the rotor sleeve 220 and the rotor shaft, thereby reducing magnetic leakage.

[0045] The present invention also provides a permanent magnet synchronous motor, which comprises the rotor according to the embodiment of the present invention. The permanent magnet synchronous motor may be, for example, a synchronous motor, a brushless DC motor, etc.

[0046] In this document, unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the utility model belongs. The words "first", "second" and similar words used in the patent application specification and claims of the utility model do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not necessarily indicate quantity restrictions. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0047] The exemplary implementation scheme of the scheme proposed in the utility model is described in detail above with reference to the preferred embodiments. However, it can be understood by those skilled in the art that, without departing from the concept of the utility model, various modifications and variations can be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the utility model can be combined in various ways without exceeding the protection scope of the utility model, which is determined by the attached claims.

Claims

1. A rotor for a permanent magnet synchronous motor, characterized in that: The rotor comprises: A first permanent magnet, which is configured as a hollow cylinder and is formed in one piece, wherein a plurality of spacing grooves are arranged in a circumferential direction inside the first permanent magnet, and the first permanent magnet is divided into a plurality of first permanent magnet sub-parts by the spacing grooves; a second permanent magnet, the second permanent magnet being arranged in the spacing slot; A plurality of positioning holes are arranged inside the first permanent magnet along the circumferential direction, the positioning holes are arranged between the spacing groove and the inner circumference of the first permanent magnet, and the positioning holes penetrate the first permanent magnet in the longitudinal direction; The plurality of first permanent magnet sub-portions form alternating magnetic poles, and the positioning holes are designed so that positioning rods pass through the positioning holes to connect the plurality of rotors in series in the longitudinal direction, and the same magnetic poles of the plurality of rotors are aligned in the longitudinal direction.

2. The rotor according to claim 1, characterized in that The number of the positioning holes is equal to the number of pole pairs of the rotor, and the positioning holes are arranged on the center line of two magnetic poles from the N pole to the S pole in the clockwise direction along the circumferential direction.

3. The rotor according to claim 1, characterized in that The rotor has a plastic-encapsulated shell, and the plastic-encapsulated shell surrounds two end surfaces of the rotor.

4. The rotor according to claim 1, characterized in that The cross section of the spacing groove is configured as a trapezoid, and a lower base of the trapezoidal cross section is close to the inner circumference of the first permanent magnet.

5. The rotor according to claim 1, characterized in that A positioning portion is provided in the spacing groove. The positioning portion is configured as a protrusion and is arranged in the spacing groove at a side close to the inner circumference of the first permanent magnet.

6. The rotor according to claim 1, characterized in that The second permanent magnet disposed in the spacing groove is provided with an air groove between the first permanent magnet and the first permanent magnet on a side facing the inner circumference of the first permanent magnet.

7. The rotor according to claim 1, characterized in that The outer circumferential surface of the first permanent magnet is a closed surface.

8. The rotor according to claim 1, characterized in that The spacing groove penetrates the first permanent magnet along a longitudinal direction of the first permanent magnet.

9. The rotor according to claim 1, characterized in that The material of the first permanent magnet is plastic ferrite.

10. The rotor according to claim 1, characterized in that The spacing groove is used to accommodate a magnetic field applying device during the orientation and magnetization process, so that the first permanent magnet obtains permanent magnetism; Wherein, the first permanent magnet sub-portion has a magnetic field direction extending along the radial direction of the first permanent magnet, and the first permanent magnet sub-portions on both sides of the spacing slot have opposite magnetic field directions respectively; Wherein, the magnetic field direction of the second permanent magnet extends along the circumferential direction of the first permanent magnet; and The magnetic field of the second permanent magnet in the spacing slot and the magnetic field of the first permanent magnet on both sides of the spacing slot together form a continuous magnetic circuit with the shortest path.

11. A permanent magnet synchronous motor, comprising a rotor according to any one of the preceding claims.

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