Embedded rotor, electric motor, method for manufacturing embedded rotor and die for casting embedded rotor

Abstract

Provided in the present invention is an embedded rotor. The embedded rotor comprises: a first permanent magnet, which is configured as a cylinder and is integrally formed, wherein a plurality of spacing slots are provided in a circumferential direction, and the first permanent magnet is divided into a plurality of first permanent magnet sub-parts by the spacing slots; and second permanent magnets, which are arranged in the spacing slots. The spacing slots are configured to accommodate a magnetic field application device during orientation and magnetization, so that the first permanent magnet obtains permanent magnetism. In addition, the present invention further relates to an electric motor comprising the embedded rotor, and a method for manufacturing the embedded rotor.

Description

Inline rotor, motor, method for manufacturing an inline rotor, and mold for casting an inline rotor

[0001] This application claims priority to Chinese patent applications No. 202410167807.8 and No. 202420275000.1, No. 202420277275.9 and No. 202420278268.0 filed on February 5, 2024, and the contents of the above-mentioned Chinese patent applications are hereby incorporated by reference in their entirety as part of this application. Technical Field

[0002] The present disclosure relates to an inline rotor, a motor including the inline rotor, a method for manufacturing the inline rotor, and a mold for casting the inline rotor. Background Art

[0003] Current embedded rotors consist of magnetizers and permanent magnets. The magnetizers are formed by stacking stamped silicon steel sheets, and the permanent magnets are embedded within the magnetizers. The silicon steel sheets that make up the magnetizers can be, for example, non-oriented or oriented silicon steel sheets. Non-oriented silicon steel sheets have very little difference in magnetic permeability or magnetic properties in all directions, meaning there is no directional difference. However, oriented silicon steel sheets have differences in magnetic permeability or magnetic properties in different directions, meaning they have excellent magnetic permeability in certain directions but poorer permeability in other directions.

[0004] When the embedded rotor's magnetizer uses non-oriented silicon steel sheets, the magnetization depth of the magnetizer is insufficient. When using oriented silicon steel sheets, the magnetization of the magnetizer is uneven due to the specific orientation of the silicon steel sheets. Furthermore, the magnetizer itself is non-magnetic, which results in wasted rotor space, underutilization of the rotor space, and failure to maximize the rotor's magnetic flux.

[0005] Summary of the Invention

[0006] The present disclosure proposes an embedded rotor, which can effectively increase the magnetization depth of the rotor, thereby improving the performance of the rotor and the motor having the rotor.

[0007] The present disclosure proposes an embedded rotor, which includes: a first permanent magnet, which is constructed as a cylinder and is integrally formed, and a plurality of spacing grooves are arranged in the circumferential direction inside the first permanent magnet, and the first permanent magnet is divided into a plurality of first permanent magnet sub-portions by the spacing grooves; a second permanent magnet, which is arranged in the spacing grooves; wherein the spacing grooves are used to accommodate a magnetic field application device during the orientation and magnetization process, so that the first permanent magnet obtains permanent magnetism.

[0008] In an embodiment according to the present disclosure, 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 wherein the magnetic field of the second permanent magnet in the spacing slot together with the magnetic fields of the first permanent magnets on both sides of the spacing slot form a continuous magnetic circuit with the shortest path.

[0009] In an embodiment according to the present disclosure, the outer circumferential surface of the first permanent magnet is a closed surface, and wherein the spacing groove penetrates the first permanent magnet along the longitudinal direction of the first permanent magnet.

[0010] In an embodiment of the present disclosure, the material of the first permanent magnet is plastic ferrite.

[0011] In an embodiment according to the present disclosure, the second permanent magnet is made of one or more of ferrite, neodymium iron boron, samarium iron nitrogen, and samarium cobalt.

[0012] In an embodiment according to the present disclosure, the cross section of the second permanent magnet is configured as a trapezoid, and wherein a lower base of the trapezoidal cross section is close to the center of the cross section of the first permanent magnet.

[0013] In an embodiment according to the present disclosure, an air slot is provided between the second permanent magnet arranged in the spacing slot and the first permanent magnet on a side facing the central axis of the first permanent magnet.

[0014] In an embodiment according to the present disclosure, the first permanent magnet is cast integrally through a gate, the first permanent magnet sub-portion has a gate spout corresponding to the gate, the gate spout is located at an end surface of the first permanent magnet, and the gate spout is closer to the outer circumference of the first permanent magnet than to the inner circumference of the first permanent magnet.

[0015] In an embodiment according to the present disclosure, each first permanent magnet sub-portion has a respective gate sprue, and the number of the gate sprues is equal to the number of poles of the rotor.

[0016] In an embodiment according to the present disclosure, the gate tip protrudes from an end surface of the first permanent magnet.

[0017] In an embodiment according to the present disclosure, a plurality of positioning holes are arranged along the circumferential direction inside the first permanent magnet, 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; and wherein, the plurality of first permanent magnet sub-portions form alternating magnetic poles, and the positioning holes are designed so that a positioning rod passes 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.

[0018] In an embodiment according to the present disclosure, the number of the positioning holes is equal to the number of pole pairs of the rotor, and the positioning holes are arranged on a dividing line between two magnetic poles from the N pole to the S pole in a clockwise direction along the circumferential direction.

[0019] In an embodiment according to the present disclosure, the embedded rotor includes a plastic packaging structure, which includes two plastic packaging cover parts covering two end surfaces of the first permanent magnet that are opposite in the axial direction and fixes each second permanent magnet relative to the spacing slot.

[0020] In an embodiment of the present disclosure, a first through hole is provided on the first permanent magnet that passes through the two end faces in the axial direction, the plastic package structure is an integral component and includes a first filling portion that fills the first through hole, and the two plastic package covers are connected by the first filling portion, wherein the rotor includes a plurality of first through holes, each of which is provided between each pair of adjacent two spacing slots, wherein the second permanent magnet has an edge groove extending in the axial direction, so that there is a second through hole that passes through the two end faces between the hole wall of each spacing slot and the corresponding edge groove of the second permanent magnet. The plastic packaging structure includes a second filling portion filling the second through hole, and the two plastic packaging cover portions are connected by the second filling portion, wherein the shape of the spacing groove and the second permanent magnet is configured so that a third through hole penetrating the two end faces is further provided between the hole wall of each spacing groove and the corresponding second permanent magnet, and the plastic packaging structure includes a third filling portion filling the third through hole, and the two plastic packaging cover portions are connected by the third filling portion, and wherein the second through hole and the third through hole are positioned at both ends of the spacing groove in the radial direction of the first permanent magnet.

[0021] In an embodiment of the present disclosure, the first permanent magnet further includes a plurality of first grooves extending in the circumferential direction of the first permanent magnet on the two end faces, each first groove being located between each pair of adjacent two spacing grooves, and the plastic packaging structure further includes a first rib filling the first grooves, wherein the second permanent magnet includes two second permanent magnet surfaces opposite to each other in the axial direction, and includes a second groove extending in the circumferential direction of the first permanent magnet on the second permanent magnet surface, and the plastic packaging structure further includes a second rib filling the second groove, and wherein the first groove and the second groove are staggered in the radial direction of the first permanent magnet, so that the first rib at both ends in the circumferential direction of the first permanent magnet respectively abuts the second permanent magnet, and the second rib at both ends in the circumferential direction of the first permanent magnet respectively abuts the first permanent magnet.

[0022] In an embodiment of the present disclosure, the plastic cover is provided with a rib protruding in the axial direction on a side facing away from the first permanent magnet.

[0023] The present disclosure also provides a motor, which includes the embedded rotor according to the above embodiments of the present disclosure.

[0024] The present disclosure also proposes a method for manufacturing an embedded rotor, the method comprising: manufacturing a first permanent magnet in an integral manner by injection molding, wherein the first permanent magnet is constructed as a cylinder and is integrally molded, 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-portions by the spacing grooves; arranging a first magnetic field applying device in the spacing grooves, and orienting the first permanent magnet so that the first permanent magnet sub-portions on both sides of the spacing grooves respectively have orientations in opposite directions along the radial direction of the first permanent magnet; manufacturing a second permanent magnet; orienting the second permanent magnet so that the orientation of the second permanent magnet extends along the circumferential direction of the first permanent magnet; arranging the second permanent magnet in the spacing grooves; and magnetizing the first permanent magnet and the second permanent magnet according to the orientation of the first permanent magnet and the orientation of the second permanent magnet, so that the magnetic field of the second permanent magnet in the spacing grooves together with the magnetic field of the first permanent magnets on both sides of the spacing grooves form a continuous magnetic circuit with the shortest path.

[0025] The present disclosure also proposes a method for manufacturing an embedded rotor, the method comprising: manufacturing a first permanent magnet, wherein the first permanent magnet is constructed as a cylinder and is integrally formed, and a plurality of spacing slots are arranged in the circumferential direction inside the first permanent magnet, and the first permanent magnet is divided into a plurality of first permanent magnet sub-sections by the spacing slots; arranging a first magnetic field applying device in the spacing slots, and orienting the first permanent magnet so that the first permanent magnet sub-sections on both sides of the spacing slots have opposite orientations along the radial direction of the first permanent magnet; magnetizing the first permanent magnet according to the orientation of the first permanent magnet; manufacturing a second permanent magnet; orienting the second permanent magnet so that its orientation extends along the circumferential direction of the first permanent magnet; magnetizing the second permanent magnet according to its orientation; and arranging the second permanent magnet in the spacing slots; wherein the magnetic field of the second permanent magnet in the spacing slots, together with the magnetic field of the first permanent magnets on both sides of the spacing slots, forms a continuous magnetic circuit with the shortest path. In the prior art, the magnetizer of the rotor is usually formed by stamping and stacking silicon steel sheets. However, the magnetization depth of non-oriented silicon steel sheets is generally not deep enough; and the magnetic conductivity direction of oriented silicon steel sheets is fixed, resulting in uneven magnetization depth after magnetization. Furthermore, manufacturing and assembling silicon steel sheets according to a desired orientation, such as that described in the embodiments of the present disclosure, is inherently complex and costly.

[0026] Compared with the prior art, the embedded rotor according to the present invention adopts a first permanent magnet instead of a magnetizer. The first permanent magnet itself is magnetic and can provide additional magnetic flux. The rotor can therefore provide more magnetic flux, and a synchronous motor with such a rotor can obtain greater power and stronger performance. In the embedded rotor according to the present invention, a magnetic field application device, such as a strong magnetic device, can be arranged in the spacing slots in the first permanent magnet to orient and magnetize the first permanent magnet, so that the first permanent magnet obtains a desired magnetic field, for example, a deep orientation depth and magnetization depth in the radial direction of the first permanent magnet. In addition, the one-piece first permanent magnet is made of magnetic material, and preferably a magnetic material with low magnetic resistance and good magnetic permeability can be selected, and the processing technology of the one-piece first permanent magnet is simple, saves materials, is low in cost, and is very suitable for industrial mass production.

[0027] Hereinafter, the best embodiment for implementing the present disclosure will be described in more detail with reference to the accompanying drawings so that the features and advantages of the present disclosure can be easily understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some exemplary embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0029] FIG1 shows a perspective view of an embedded rotor according to an embodiment of the present disclosure;

[0030] FIG2 shows an exploded perspective view of an inline rotor according to an embodiment of the present disclosure;

[0031] FIG3 is a schematic diagram showing the magnetic field direction of the first permanent magnet of the embedded rotor according to an embodiment of the present disclosure;

[0032] FIG4 is a schematic diagram showing the magnetic field direction of the second permanent magnet of the embedded rotor according to an embodiment of the present disclosure;

[0033] FIG5 shows a schematic diagram of a magnetic circuit of an embedded rotor according to an embodiment of the present disclosure;

[0034] FIG6 shows a flow chart of a method for manufacturing an embedded rotor according to an embodiment of the present disclosure;

[0035] FIG7 shows a flow chart of a method for manufacturing an inline rotor according to another embodiment of the present disclosure;

[0036] FIG8 shows an exploded perspective view of a rotor for a permanent magnet synchronous motor according to an embodiment of the present invention;

[0037] FIG9 shows a cross-sectional view of a first permanent magnet according to an embodiment of the present invention;

[0038] FIG10 is a schematic diagram showing the magnetic field direction of the first permanent magnet according to an embodiment of the present invention;

[0039] FIG11 is a schematic diagram showing the magnetic field direction of the rotor according to an embodiment of the present invention;

[0040] FIG12 shows a cross-sectional view of a first permanent magnet according to another embodiment of the present invention;

[0041] FIG13 shows an exploded perspective view of a rotor for a permanent magnet synchronous motor according to an embodiment of the present invention;

[0042] FIG14 shows a cross-sectional view of a first permanent magnet of a rotor according to an embodiment of the present invention;

[0043] FIG15 shows a perspective view of rotors connected in series in the longitudinal direction according to an embodiment of the present invention;

[0044] FIG16 shows a perspective cross-sectional view of rotors connected in series in the longitudinal direction according to an embodiment of the present invention;

[0045] FIG17 is a perspective schematic diagram of a rotor before plastic packaging according to an embodiment of the present disclosure;

[0046] FIG18 shows a schematic plan view of the rotor according to FIG17 ;

[0047] FIG19 shows an exploded schematic diagram of the rotor according to FIG17 ;

[0048] FIG20 is a partial cross-sectional perspective diagram of a rotor after plastic sealing according to an embodiment of the present disclosure;

[0049] FIG21 shows a plan view of a cross-sectional view of the rotor of FIG20; and

[0050] FIG22 shows a perspective schematic diagram of a rotor after plastic packaging according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the technical solution of the present disclosure clearer, the technical solution of the embodiment of the present disclosure will be clearly and completely described below in conjunction with the drawings of the specific embodiments of the present disclosure. 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 present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0052] Compared to the embodiments shown in the drawings, feasible embodiments within the scope of protection of the present disclosure may have fewer components, additional 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.

[0053] Figure 1 schematically illustrates a perspective view of an embedded rotor 100 according to an embodiment of the present disclosure. The embedded rotor 100 includes a first permanent magnet 110 and a second permanent magnet 120. The first permanent magnet 110 is configured as a cylinder and is integrally formed. In the present disclosure, "the first permanent magnet 110 is configured as a cylinder" specifically means that the outer contour of the first permanent magnet 110 is cylindrical. In embodiments of the present disclosure, the outer circumferential surface of the first permanent magnet 110 can be, for example, a closed surface to provide greater structural strength. Figure 2 schematically illustrates an exploded perspective view of the embedded rotor 100 according to an embodiment of the present disclosure. As can be clearly seen in Figure 2, a plurality of spacing slots 130 are arranged circumferentially within the first permanent magnet 110, separating the first permanent magnet into a plurality of first permanent magnet sub-segments. In embodiments of the present disclosure, the spacing slots 130 extend longitudinally through the first permanent magnet 110, i.e., in the axial direction of the first permanent magnet 110. The plurality of second permanent magnets 120 are respectively arranged in the spacing grooves 130 , in particular, inserted into the spacing grooves 130 .

[0054] 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.

[0055] In the prior art, permanent magnets in rotors are typically made of high-energy-product materials, such as neodymium iron boron. High-energy-product materials are expensive and have limited magnetization depth. Permanent magnets made of high-energy-product materials are typically placed on a magnetizer in an embedded or surface-mounted manner. Permanent magnets made of high-energy-product materials and rotors having such permanent magnets are typically small in size. In this case, it is necessary to enlarge the stator or increase the stator coils to increase the power of the synchronous motor. In contrast, in the present disclosure, the first permanent magnet can be made of a low-energy-product material, such as plastic magnets. Plastic magnet materials are relatively inexpensive. Deep orientation and magnetization of the first permanent magnet can be achieved through spacing slots in the first permanent magnet. Based on these two points, the first permanent magnet can be constructed as large as possible, and a rotor having such a first permanent magnet can provide a stronger magnetic field and more magnetic flux. The rotor according to the present disclosure can achieve the performance of a rotor made of high-energy-product materials.

[0056] In the prior art, the rotor of a permanent magnet synchronous motor consists of a magnetizer and permanent magnets. The permanent magnets can be attached to the magnetizer's surface to form a surface-mounted rotor, or inserted into the magnetizer to form an embedded rotor. These magnetizers are formed by stamping and stacking silicon steel sheets, making them difficult to manufacture using an integrated molding process.

[0057] Compared with the prior art, a first permanent magnet is used in place of a magnetizer in the rotor according to the present disclosure. The first permanent magnet according to the present disclosure is made of plastic magnetic material by injection molding and can be very conveniently prepared through an integrated molding process. Compared with the process of stamping and stacking silicon steel sheets, the integrated molding process of the first permanent magnet is simple in process, high in efficiency, high in precision, and low in 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 rotor according to the present disclosure has a deeper magnetization depth, a higher material utilization rate, and a greater power density.

[0058] In this disclosure, one-piece molding is understood to mean the process of molding an entire part in a single mold. Compared to traditional, step-by-step manufacturing processes, one-piece molding significantly reduces production costs and accelerates production, enabling the production of a wide variety of parts, products, and tools in a fraction of the time.

[0059] The one-piece molding process is relatively simple and can complete the required contours, holes, surface treatments, etc. in one mold, which can greatly reduce production time and costs, while improving the production accuracy and repeatability of parts. In traditional processing methods, 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 and other requirements, and can truly be completed in one step, greatly improving processing efficiency and speed. In addition, the molds designed for the one-piece molding process are usually produced in one go, 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 traditional manufacturing fields, but can also 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.

[0060] The integrally molded first permanent magnet is made of a magnetic material, and preferably a magnetic material with low magnetic resistance and good magnetic permeability can be selected. In an embodiment according to the present disclosure, the first permanent magnet 110 can be made of, for example, plastic ferrite, for example, molded in one step by an injection molding method. Plastic ferrite has low magnetic resistance, good magnetic permeability, deep magnetization depth, and is suitable for integral molding and industrial production. In an embodiment according to the present disclosure, the plastic ferrite can be, for example, a mixture of nylon and ferrite. 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 its volume. Plastic ferrite has a lower density than silicon steel material, which results in a reduced weight of the rotor made of plastic ferrite, thereby improving the power and energy efficiency of the motor. 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.

[0061] FIG3 schematically illustrates the magnetic field orientation of the first permanent magnet 110 of the embedded rotor 100 according to an embodiment of the present disclosure. FIG3 illustrates a cross-section of the embedded rotor 100 and its first permanent magnet 110. As shown in FIG3 , the first permanent magnet sub-segments 111 and 112 on either side of a spacing slot 130 have opposite magnetic field orientations along the radial direction of the first permanent magnet 110. For example, the magnetic field orientation of the first permanent magnet sub-segment 111 is oriented outward along the radial direction of the first permanent magnet 110, while the magnetic field orientation of the first permanent magnet sub-segment 112 is oriented inward along the radial direction of the first permanent magnet 110. The magnetic field orientation of the first permanent magnet 110 and its respective first permanent magnet sub-segments is the magnetic field orientation after magnetization or after the inserted second permanent magnet 120 is magnetized. It should be noted that the orientation direction of the first permanent magnet 110 is consistent with the magnetic field orientation of the first permanent magnet 110 and its respective first permanent magnet sub-segments. When the first permanent magnet 110 and its respective first permanent magnet sub-portions are oriented, each first permanent magnet sub-portion of the first permanent magnet will have better magnetic conductivity, that is, higher magnetic permeability and lower magnetic resistance in a specific direction due to the externally applied directional magnetic field.

[0062] The second permanent magnet 120 is inserted into the spacing slot 130 to provide a magnetic field. The magnetic field direction of the second permanent magnet 120 is designed so that the first permanent magnet sub-segments 111 and 112 on either side of one of the spacing slots 130 and the second permanent magnet 120 form a continuous magnetic circuit with the shortest path. Figure 4 shows a schematic diagram of the magnetic field direction of the second permanent magnets 121 and 122 of the embedded rotor 100 according to an embodiment of the present disclosure. Figure 4 exemplifies two adjacent second permanent magnets 121 and 122. The magnetic field direction of the second permanent magnets 121 and 122 will be described below using only the second permanent magnets 121 and 122 as an example. The magnetic field direction of the second permanent magnets 121 and 122 can be used to understand the magnetic field direction of the remaining second permanent magnets by comparison. In an embodiment of the present disclosure, the magnetic field direction of the second permanent magnets 120, 121, and 122 can extend along the circumference of the first permanent magnet 110. As can be seen from Figure 4, the magnetic field directions of two adjacent second permanent magnets 121 and 122 are opposite. This magnetic field direction of the second permanent magnets 120, 121 and 122 causes the first permanent magnet sub-portions on both sides of an interval slot and the second permanent magnet in the interval slot to form a continuous magnetic circuit with the shortest path. This is more clearly shown in Figure 5. In an embodiment according to the present disclosure, the materials of the second permanent magnets 120, 121 and 122 can include, for example, ferrite, neodymium iron boron, samarium iron nitride and samarium cobalt. The second permanent magnet composed of samarium cobalt, neodymium iron boron or samarium iron nitride has strong remanence, high power density, high coercive force, and good anti-demagnetization ability, and is therefore very suitable for high-power, high-torque motors. In an embodiment according to the present disclosure, the second permanent magnets 120, 121 and 122 can be, for example, sintered or bonded, and can be, for example, sintered ferrite. When the second permanent magnets are made of sintered ferrite, the entire rotor does not use any rare earth materials, thereby further reducing the cost of the rotor.

[0063] From the outside, the embedded rotor according to the present disclosure has alternating north and south poles, forming a rotor with multiple pole pairs. Inside the embedded rotor according to the present disclosure, the first permanent magnet subsection corresponding to the south pole has a magnetic field direction extending radially inward, while the first permanent magnet subsection corresponding to the north pole has a magnetic field direction extending radially outward. Between adjacent south and north poles, the magnetic field originates from the south pole, transitions through the second permanent magnet via the shortest path, and reaches the north pole. The magnetic field in the second permanent magnet extends in the circumferential direction. Specifically, Figure 5 shows a schematic diagram of the magnetic circuit of the embedded rotor 100 according to an embodiment of the present disclosure. As shown in Figure 5, the second permanent magnet 121 is arranged in the spacing slot 131, the second permanent magnet 122 is arranged in the spacing slot 132, and the second permanent magnet 123 is also shown, which is arranged in the spacing slot 133. The magnetic field direction of the second permanent magnet 123 extends in the circumferential direction of the first permanent magnet 110 and is opposite to the magnetic field direction of the adjacent second permanent magnet 122. On either side of the second permanent magnet 122 or spacing slot 132 are the first permanent magnet sub-segments 111 and 112, and on either side of the second permanent magnet 123 or spacing slot 133 are the first permanent magnet sub-segments 112 and 113. As shown in FIG5 , the magnetic field originates from the south pole corresponding to the first permanent magnet sub-segment 112 and extends inward in the radial direction of the first permanent magnet 110 within the first permanent magnet sub-segment 112. The magnetic field then splits, with one portion bending through the second permanent magnet 122 and the other portion bending through the second permanent magnet 123. The magnetic field in the second permanent magnet 122 extends counterclockwise along the circumference of the first permanent magnet 110. After passing through the second permanent magnet 122, the magnetic field bends and extends outward in the radial direction of the first permanent magnet 110, through the first permanent magnet sub-segment 111, and reaches the north pole corresponding to the first permanent magnet sub-segment 111. The magnetic field in the second permanent magnet 123 extends clockwise along the circumferential direction of the first permanent magnet 110. After passing through the second permanent magnet 123, the magnetic field bends and extends outward in the radial direction of the first permanent magnet 110, passing through the first permanent magnet sub-segment 113, and reaching the corresponding north pole of the first permanent magnet sub-segment 113. Based on the above description of the direction and orientation of the magnetic field in the first permanent magnet sub-segments 111, 112, and 113 and the second permanent magnets 122 and 123, the direction and orientation of the magnetic field in the other first permanent magnet sub-segments and second permanent magnets can be understood by comparison.

[0064] In the prior art, rotor magnets are typically formed by stamping and stacking silicon steel sheets. However, the magnetization depth of non-oriented silicon steel sheets is generally insufficient, while the magnetization direction of oriented silicon steel sheets is fixed, resulting in uneven magnetization depth after magnetization. Furthermore, manufacturing and assembling silicon steel sheets according to a desired orientation, such as that described in the embodiments of this disclosure, is inherently complex and costly.

[0065] Compared with the prior art, the embedded rotor according to the present invention adopts a first permanent magnet instead of a magnetizer. The first permanent magnet itself is magnetic and can provide additional magnetic flux. The rotor can therefore provide more magnetic flux, and a synchronous motor with such a rotor can obtain greater power and stronger performance. In the embedded rotor according to the present invention, a magnetic field application device, such as a strong magnetic device, can be arranged in the spacing slots in the first permanent magnet to orient and magnetize the first permanent magnet, so that the first permanent magnet obtains a desired magnetic field, for example, a deep orientation depth and magnetization depth in the radial direction of the first permanent magnet. In addition, the one-piece first permanent magnet is made of magnetic material, and preferably a magnetic material with low magnetic resistance and good magnetic permeability can be selected, and the processing technology of the one-piece first permanent magnet is simple, saves materials, is low in cost, and is very suitable for industrial mass production.

[0066] In the embodiment according to the present disclosure, the cross-section of the second permanent magnet 120 and the cross-section of the spacing slot 130 matched therewith can be configured into any shape, such as a triangle, a quadrilateral, other polygons, a circle, and the like.

[0067] In an embodiment of the present disclosure, the cross-section of the second permanent magnet 120 can be configured as a trapezoid, for example, as shown in Figures 1 to 5. Furthermore, in an embodiment of the present disclosure, the lower base of the trapezoidal cross-section is close to the center of the cross-section of the first permanent magnet 110, while the upper base of the trapezoidal cross-section is close to the circumference of the cross-section of the first permanent magnet 110. The trapezoidal cross-section of the second permanent magnet 120 allows more of the magnetic field to pass through the first permanent magnet, thereby reducing magnetic flux leakage.

[0068] In an embodiment according to the present disclosure, as shown in Figures 1 and 3, a positioning portion 141 can be provided in the spacing groove 130, for example, and the positioning portion 141 is used to fix the second permanent magnet 120 in the spacing groove 130. In an embodiment according to the present disclosure, the positioning portion 141 is arranged in the spacing groove 130 on one side of the center of the cross section of the first permanent magnet 110 close to the center of the circle. In an embodiment according to the present disclosure, the positioning portion 141 is constructed as a protrusion for abutting against the second permanent magnet, and the protrusion can be constructed 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. Therefore, it is necessary to provide a positioning portion 141 so that the second permanent magnet 120 can be fixed in the spacing groove 130.

[0069] In an embodiment of the present disclosure, as shown in Figures 1 and 3, an air slot 142 is provided between the second permanent magnet 120 disposed in the spacing slot 130 and the first permanent magnet 110 on the side facing the central axis of the first permanent magnet 110. The air slot 142 can, for example, be naturally formed when the positioning portion 141 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 large size of the spacing slot. Because air has a very low magnetic permeability, the air slot 142 can reduce magnetic flux leakage.

[0070] The present disclosure also provides a motor, comprising the above-mentioned embedded rotor according to the present disclosure. The motor may be, for example, a synchronous motor, a brushless DC motor, or the like.

[0071] The present disclosure also proposes a method for manufacturing an embedded rotor. FIG6 shows a flow chart of a method 600 for manufacturing an embedded rotor according to an embodiment of the present disclosure. The method 600 for manufacturing an embedded rotor shown in FIG6 includes: manufacturing a first permanent magnet, wherein the first permanent magnet is constructed as a cylinder and is integrally formed, 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-portions by the spacing grooves (step S610); a first magnetic field application device is arranged in the spacing grooves, and the first permanent magnet is oriented so that the first permanent magnet sub-portions on both sides of the spacing grooves have opposite orientations along the radial direction of the first permanent magnet. (Step S620); manufacture a second permanent magnet (Step S630); orient the second permanent magnet so that its orientation extends along the circumferential direction of the first permanent magnet (Step S640); arrange the second permanent magnet in the spacing slot (Step S650); magnetize the first permanent magnet and the second permanent magnet according to the orientation of the first permanent magnet and the orientation of the second permanent magnet, so that 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. (Step S660). It should be noted that the orientation direction of the first permanent magnet and the second permanent magnet is consistent with the magnetic field direction of the first permanent magnet after magnetization shown in Figures 3 and 5, and when the first permanent magnet and the second permanent magnet are magnetized, the magnetization direction is consistent with the orientation direction of the first permanent magnet and the orientation direction of the second permanent magnet. The magnetized embedded rotor is formed into the embedded rotor according to the embodiment of the present disclosure described above.

[0072] In the method for manufacturing an embedded rotor according to an embodiment of the present disclosure, since the first permanent magnet and the second permanent magnet have been pre-oriented, the first permanent magnet and the second permanent magnet have better magnetic permeability in the orientation direction. Therefore, when magnetization is subsequently performed, the magnetic circuit of the first permanent magnet and the second permanent magnet will generally and therefore have a better magnetization depth.

[0073] In an embodiment of the present disclosure, the first permanent magnet can be manufactured, for example, in an integral manner, using injection molding. The processing of the integrally molded first permanent magnet is simple and cost-effective. For example, the first permanent magnet can be manufactured in an integral manner using magnetic materials. Preferably, a magnetic material with low magnetic resistance and good magnetic permeability can be selected. In an embodiment of the present disclosure, the first permanent magnet can be manufactured, for example, using plastic magnets. Plastic magnets have low magnetic resistance, good magnetic permeability, and deep magnetization depth, making them suitable for integral molding and industrial production.

[0074] The present disclosure also proposes another method for manufacturing an inline rotor. FIG7 shows a flow chart of a method 700 for manufacturing an inline rotor according to another embodiment of the present disclosure. The method 700 for manufacturing an embedded rotor shown in Figure 7 includes: manufacturing a first permanent magnet, wherein the first permanent magnet is constructed as a cylinder and is integrally formed, and a plurality of spacing grooves are arranged inside the first permanent magnet along the circumferential direction, and the first permanent magnet is divided into a plurality of first permanent magnet sub-portions by the spacing grooves (step S710); arranging a first magnetic field application device in the spacing grooves, and orienting the first permanent magnet so that the first permanent magnet sub-portions on both sides of the spacing grooves have opposite orientations along the radial direction of the first permanent magnet (step S720); magnetizing the first permanent magnet according to the orientation of the first permanent magnet; (step S730); manufacturing a second permanent magnet (step S740); orienting the second permanent magnet so that the orientation of the second permanent magnet extends along the circumferential direction of the first permanent magnet (step S750); magnetizing the second permanent magnet according to the orientation of the second permanent magnet (step S760); and arranging the second permanent magnet in the spacing grooves (step S770). The magnetic field of the second permanent magnet in the spacing slot, together with the magnetic field of the first permanent magnet on either side of the spacing slot, forms a continuous magnetic circuit with the shortest path. It is important to note that the orientation of the first and second permanent magnets is consistent with the magnetic field direction of the first permanent magnet after magnetization, as shown in Figures 3 and 5 . Furthermore, when the first and second permanent magnets are magnetized, the magnetization direction is consistent with the orientation of the first and second permanent magnets. After magnetization, the embedded rotor becomes the embedded rotor according to the above-mentioned embodiment of the present disclosure.

[0075] In the method for manufacturing an embedded rotor according to an embodiment of the present disclosure, since the first permanent magnet and the second permanent magnet have been pre-oriented, the first permanent magnet and the second permanent magnet have better magnetic permeability in the orientation direction. Therefore, when magnetization is subsequently performed, the magnetic circuit of the first permanent magnet and the second permanent magnet will generally and therefore have a better magnetization depth.

[0076] In an embodiment of the present disclosure, the first permanent magnet can be manufactured, for example, in an integral manner, using injection molding. The processing of the integrally molded first permanent magnet is simple and cost-effective. For example, the first permanent magnet can be manufactured in an integral manner using magnetic materials. Preferably, a magnetic material with low magnetic resistance and good magnetic permeability can be selected. In an embodiment of the present disclosure, the first permanent magnet can be manufactured, for example, using plastic magnets. Plastic magnets have low magnetic resistance, good magnetic permeability, and deep magnetization depth, making them suitable for integral molding and industrial production.

[0077] Figure 8 schematically shows an exploded view of a rotor 800 for a permanent magnet synchronous motor according to an embodiment of the present invention. The rotor 800 includes a first permanent magnet 810 and a second permanent magnet 820. The first permanent magnet 810 is configured as a hollow cylinder. In the present invention, the first permanent magnet 810 being configured as a hollow cylinder is particularly understood to mean that the outer contour of the first permanent magnet 810 is a hollow cylinder. In an embodiment of the present invention, the outer circumferential surface of the first permanent magnet 810 can be, for example, a closed surface to provide greater structural strength. A plurality of spacing grooves 830 are arranged circumferentially within the first permanent magnet 810, separating the first permanent magnet 810 into a plurality of first permanent magnet sub-segments 811 by the spacing grooves 830. In an embodiment of the present invention, the spacing grooves 830 extend axially through the first permanent magnet 810. The plurality of second permanent magnets 820 are respectively disposed in, and in particular, inserted into, the spacing grooves 830.

[0078] The first permanent magnet 810 is cast in an integral manner. The mold for casting the first permanent magnet 810 has a gate. After the cast first permanent magnet 810 is removed from the mold, the first permanent magnet 810 forms a gate tip at a position corresponding to the gate. Therefore, as can be seen from Figure 8, the first permanent magnet 810 has a gate tip 930 corresponding to the gate, and the gate tip 930 is located at the end face of the first permanent magnet 810. In the present invention, the gate tip 930 is closer to the outer circumference of the first permanent magnet 830 than the inner circumference of the first permanent magnet 830. In other words, during the casting of the first permanent magnet 810, the gate on the mold is closer to the outer circumference of the first permanent magnet 810 than the inner circumference of the first permanent magnet 830, and preferably abuts against the outer circumference of the first permanent magnet 810.

[0079] In the prior art, the rotor of a permanent magnet synchronous motor consists of a magnetizer and a second permanent magnet. The second permanent magnet can be attached to the surface of the magnetizer to form a surface-mounted rotor, or the second permanent magnet can be inserted into the magnetizer to form an embedded rotor. This form of magnetizer is formed by stamping and stacking silicon steel sheets, and therefore cannot be manufactured through an integrated molding process. Compared with the prior art, an integrally molded first permanent magnet is used instead of the magnetizer in the rotor according to the present invention. In the present invention, the first permanent magnet can be injection molded from plastic ferrite, for example, so that it can be prepared very conveniently through an integrated molding process. The integrated molding process of the first permanent magnet is simple in process, high in efficiency, high in precision, and low in cost compared to the process of stamping and stacking silicon steel sheets. In addition, the first permanent magnet composed of plastic ferrite itself can provide a magnetic field and magnetic force, and its magnetic permeability is much higher than that of the silicon steel sheet magnetizer.

[0080] To enhance the magnetic properties of the first permanent magnet 810 itself, it is necessary to orient the first permanent magnet 810 during the casting or injection molding process so that each subsection of the first permanent magnet 810 forms anisotropic magnets. Furthermore, the first permanent magnet 810 is magnetized so that each subsection of the first permanent magnet 810 acquires magnetism in the orientation direction. During orientation, a magnetic field application device, or orientation device, is positioned on the outer circumference of the first permanent magnet 810 and has alternating, paired magnetic poles. Under the influence of the external magnetic field applied by the magnetic field application device, the magnetic poles of the magnetic particles in the plastic ferrite within the first permanent magnet 810 are aligned and oriented. The orientation direction and magnetic field direction of the first permanent magnet 810 will be described in more detail below. The plastic ferrite enters the mold through the gate. The closer the gate is to the outer circumference of the first permanent magnet 810, the stronger the magnetic field applied to the plastic ferrite and the more uniformly aligned the magnetic particles are. Under the influence of the magnetic field, the magnetic particles in the plastic ferrite cling to the outer circumference of the first permanent magnet 810, causing the magnetic particles to align from the outside inward. This increases the density of the magnetic particles and enhances the magnetic flux. Compared to an arrangement where the gate is closer to the inner circumference of the first permanent magnet 810, the orientation of the various sub-segments of the first permanent magnet 810 according to the present invention is more uniform, resulting in greater magnetic flux and improved rotor performance.

[0081] In the present invention, the term "integrated molding" should be understood as the process of completing the entire part molding process in a single mold. Compared to traditional step-by-step manufacturing processes, integrated molding significantly reduces part production costs and offers faster production speeds, enabling the rapid production of a variety of parts, products, and tools. The relatively simple process flow allows the required contours, holes, and surface treatments to be achieved in a single mold, significantly reducing production time and costs while also improving part production accuracy and repeatability. Traditional manufacturing methods require mold and template preparation before the part is processed in separate steps. Integrated molding, however, eliminates the need for additional template preparation and achieves a truly one-step process, significantly improving processing efficiency and speed. Furthermore, molds designed for integrated molding are typically produced in a single process, resulting in extremely rapid production, enabling rapid large-scale production and meeting market demand more quickly. Integrated molding not only meets the needs of traditional manufacturing but can also be applied to high-tech fields such as generators, car washes, and medical devices. In these fields, integrated molding can create more precise and high-quality parts and products.

[0082] In an embodiment of the present invention, the plastic ferrite used for injection molding the first permanent magnet has low magnetic resistance, good magnetic permeability, deep magnetization depth, and is suitable for one-piece molding and industrial production. In an embodiment of the present invention, the plastic ferrite can be, for example, a mixture of nylon and ferrite. The first permanent magnet made of plastic ferrite accommodates the second permanent magnet, and the rotor space is therefore fully utilized, so that the rotor can provide a larger magnetic flux without changing its volume. Plastic ferrite has a lower density than silicon steel material, which results in a reduced weight of the rotor made of plastic ferrite, thereby improving the power density and energy efficiency of the motor. In addition, plastic ferrite has smaller hysteresis loss than silicon steel material and has a higher resistivity, so the rotor made of plastic ferrite can have lower eddy current loss than the rotor made of silicon steel material.

[0083] In an embodiment according to the present invention, after casting and demolding, a gate sprue 930 is formed on the first permanent magnet 810 due to the presence of the gate. The gate sprue 930 may, for example, protrude from the end surface of the first permanent magnet 810. Alternatively, the gate sprue 930 may be removed, for example, by shearing off, but this may still leave a mark on the end surface of the first permanent magnet 810.

[0084] In an embodiment according to the present invention, each first permanent magnet sub-section 811 of the first permanent magnet 810 can, for example, have a respective gate sprue 930. The number of the gate sprues 930 is equal to the number of poles of the rotor. As shown in FIG8 , magnetic poles are formed in each first permanent magnet sub-section 811, and the rotor has 5 pairs of poles (10 poles). The first permanent magnet has 10 gate sprues 930. Accordingly, the mold for casting the first permanent magnet has 10 gates. The material used for casting, such as plastic ferrite, can be filled into the cavity in the shortest possible manner through the corresponding gate path to form the corresponding first permanent magnet sub-section 811. The first permanent magnet sub-section 811 and its gate respectively correspond to a magnetic pole of the magnetic field applying device, so that the material entering from the corresponding gate can be more strongly affected by the corresponding magnetic pole, thereby having a more uniform orientation and stronger magnetism.

[0085] Figure 9 shows a cross-sectional view of a first permanent magnet 810 according to an embodiment of the present invention. In this embodiment, a gate nozzle 930, for example, has a narrow cross-section in the circumferential direction, and the gate nozzle 930 closely contacts or extends to the outer circumference of the first permanent magnet 810. As mentioned above, during the injection molding process, the closer the gate is to the outer circumference of the first permanent magnet 810, the stronger the magnetic field applied by the magnetic field applying device to the plastic ferrite. To bring the gate closer to the outer circumference of the first permanent magnet 810, the gate is designed as a narrow opening in the circumferential direction, and the gate nozzle 930 has a correspondingly narrow cross-section. In this embodiment of the present invention, the circumferential length of the narrow cross-section in the circumferential direction can be, for example, more than twice the radial length, and the maximum circumferential length of the narrow cross-section in the circumferential direction can be, for example, more than twice the maximum radial length, and preferably more than twice. In a more preferred embodiment, the cross-section of the circumferentially narrow gate can form a sector ring, for example, and the outer arc of the sector ring has the same curvature as the outer circumference of the first permanent magnet 810. The gate nozzle 930 can therefore be located on the outer circumference of the first permanent magnet 810, that is, partially overlap with the contour of the outer circumference. In this case, the gate of the mold for casting the first permanent magnet 810 can be arranged on the outer circumference of the first permanent magnet 810, that is, as close to the outer circumference as possible.

[0086] In an embodiment according to the present invention, the spacing groove 830 penetrates the first permanent magnet 810 along the longitudinal direction of the first permanent magnet 810. The cross-section of the spacing groove 830 can be configured as a trapezoid, for example, with the lower base of the trapezoidal cross-section close to the inner circumference of the first permanent magnet 810 and the upper base of the trapezoidal cross-section close to the outer circumference of the first permanent magnet 810. The trapezoidal second permanent magnet 820 is arranged in the trapezoidal spacing groove 830. This arrangement allows the magnetic field to pass through the first permanent magnet 810 more, thereby reducing magnetic flux leakage.

[0087] FIG10 is a schematic diagram showing the magnetic field direction of the first permanent magnet 810 according to an embodiment of the present invention. During the casting process of the first permanent magnet 810, a magnetic field application device, namely an orientation device 1010, is arranged around the first permanent magnet 810. The orientation device 1010 has alternating pairs of magnetic poles. In the embodiment of FIG10 , five pairs of poles (10 poles) are shown. According to common regulations, outside the magnet, the magnetic field lines start from the north pole and reach the south pole; inside the magnet, the magnetic field lines start from the south pole and reach the north pole. All embodiments of the present invention describe the magnetic field direction according to the above regulations. As can be seen from FIG10 , the magnetic poles of the orientation device 1010 are arranged corresponding to each first permanent magnet sub-portion. The magnetic field applied by the orientation device 1010 extends radially in the first permanent magnet sub-portions on both sides of one of the spacing slots 830 and has opposite directions. For example, the magnetic field direction in first permanent magnet sub-segment 1011 is oriented outward along the radial direction of first permanent magnet 810, while the magnetic field direction in first permanent magnet sub-segment 1012 is oriented inward along the radial direction of first permanent magnet 810. Under the influence of an external magnetic field, the magnetic poles of the magnetic particles in a plastic magnetic material, such as plastic ferrite, change from their originally chaotic arrangement to a neat arrangement aligned with the direction of the external magnetic field. As a result, each first permanent magnet sub-segment behaves as anisotropic ferromagnetic material, with its orientation aligned with the direction of the external magnetic field. During the subsequent magnetization process, the direction of the magnetic field applied by the magnetization device aligns with the orientation direction. Under the action of the magnetization device, first permanent magnet 810 and each first permanent magnet sub-segment acquire permanent magnetism. After the orientation process, each first permanent magnet sub-segment has improved magnetic conductivity, i.e., higher magnetic permeability and lower magnetic resistance, in a specific direction.

[0088] In another embodiment of the present disclosure, during the orientation and magnetization process, in addition to the magnetic field application device disposed around the first permanent magnet 810, a magnetic field application device may also be disposed, for example, in the spacing slot 830. The magnetic field applied by the magnetic field application device in the spacing slot 830 may, for example, be the same as the magnetic field of the second permanent magnet 820. This will be described in detail later. The additional arrangement of the magnetic field application device in the spacing slot 830 allows a stronger magnetic field to be applied to the first permanent magnet and the ferromagnetic particles therein, allowing the ferromagnetic particles to align according to the desired magnetic field orientation and exhibiting improved magnetic conductivity, i.e., higher magnetic permeability and lower magnetic resistance, along the magnetic field orientation.

[0089] Figure 11 shows a schematic diagram of the magnetic field orientation of a rotor according to an embodiment of the present invention. In the embodiment shown in Figure 11, the first permanent magnet 810 of the rotor 800 has been oriented and magnetized to obtain permanent magnetism. The second permanent magnet 820 is inserted into the spacing slot 830. The magnetic field orientation of the second permanent magnet 820 is designed so that the first permanent magnet sub-sections on either side of one of the spacing slots 830 and the second permanent magnet 820 form a continuous magnetic circuit with the shortest path. In an embodiment of the present invention, the material of the second permanent magnet 820 may include, for example, ferrite, neodymium iron boron, samarium iron nitride, and samarium cobalt. Second permanent magnets composed of samarium cobalt, neodymium iron boron, or samarium iron nitride have strong remanence, high power density, high coercive force, and good demagnetization resistance, making them ideally suited for high-power, high-torque motors. In an embodiment of the present invention, the second permanent magnet 820 may be sintered or bonded, for example, sintered ferrite. In the case where the second permanent magnet is made of sintered ferrite, the entire rotor does not use any rare earth material, so the cost of the rotor is further reduced.

[0090] In the embodiment shown in FIG11 , the rotor 800 has alternating north and south poles, forming a rotor with multiple pole pairs. It should be noted that the magnetic poles of the rotor 800 or the first permanent magnet 811 shown in FIG11 are those of the external magnetic field application device 1010, while those shown in FIG10 are those of the external magnetic field application device 1010. Under the influence of the south pole of the external magnetic field application device 1010, the corresponding first permanent magnet sub-segment forms a north pole; under the influence of the north pole of the external magnetic field application device 1010, the corresponding first permanent magnet sub-segment forms a south pole. The magnetic field orientations in FIG11 and FIG10 are the same. As shown in FIG11 , the first permanent magnet sub-segment corresponding to the south pole of the rotor 800 has a magnetic field direction extending radially inward, while the first permanent magnet sub-segment corresponding to the north pole of the rotor 800 has a magnetic field direction extending radially outward. Between adjacent south and north poles of the rotor 800, the magnetic field originates from the south pole, transitions through the second permanent magnet via the shortest path, and reaches the north pole. The magnetic field in the second permanent magnet extends circumferentially. For example, second permanent magnet 1121 is arranged in spacing slot 1131, second permanent magnet 1122 is arranged in spacing slot 1132, and second permanent magnet 1123 is arranged in spacing slot 1133. The magnetic field of second permanent magnet 1123 extends along the circumference of first permanent magnet 810 and is opposite to the magnetic field of adjacent second permanent magnet 1122. First permanent magnet sub-segments 1111 and 1112 are located on either side of second permanent magnet 1122 or spacing slot 1132, and first permanent magnet sub-segments 1112 and 1113 are located on either side of second permanent magnet 1123 or spacing slot 1133. As can be seen in FIG. 11 , the magnetic field originates from the south pole corresponding to first permanent magnet sub-segment 1112 and extends inward in the radial direction of first permanent magnet 810 within first permanent magnet sub-segment 1112. The magnetic field then splits, with one portion of the magnetic field bending through the second permanent magnet 1122 and the other portion bending through the second permanent magnet 1123. The magnetic field extends counterclockwise in the second permanent magnet 1122 along the circumferential direction of the first permanent magnet 810. After passing through the second permanent magnet 1122, the magnetic field bends and extends outward in the radial direction of the first permanent magnet 810 through the first permanent magnet sub-portion 1111, reaching the north pole corresponding to the first permanent magnet sub-portion 1111. The magnetic field extends clockwise in the second permanent magnet 1123 along the circumferential direction of the first permanent magnet 810. After passing through the second permanent magnet 1123, the magnetic field bends and extends outward in the radial direction of the first permanent magnet 810 through the first permanent magnet sub-portion 1113, reaching the north pole corresponding to the first permanent magnet sub-portion 1113. Based on the above description of the directions and orientations of the magnetic fields in the first permanent magnet sub-portions 1111 , 1112 and 1113 and the second permanent magnets 1122 and 1123 , the directions and orientations of the magnetic fields in the other first permanent magnet sub-portions and second permanent magnets can be understood by comparison.

[0091] FIG12 shows a cross-sectional view of a first permanent magnet 810 according to another embodiment of the present invention. In the embodiment shown in FIG12 , the gate head 1230 has a circular cross-section. Accordingly, the gate of the mold for casting the first permanent magnet 810 also has a circular cross-section. From the perspective of mold processing and manufacturing, the processing difficulty of a circular gate is less than that of the above-mentioned narrow and long gate. However, the circular gate is generally farther away from the outer circumference of the first permanent magnet 810 than the narrow and long gate. Therefore, during casting or injection molding, the strength of the external magnetic field to which the material used for casting, such as plastic ferrite, is subjected is smaller than that of the above-mentioned narrow and long gate, and the uniformity of the orientation arrangement of the magnetic particles is smaller than that of the narrow and long gate.

[0092] The present invention further provides a permanent magnet synchronous motor, which includes the rotor according to the embodiment of the present invention. The permanent magnet synchronous motor may also be a brushless DC motor, for example.

[0093] The present invention also provides a mold. This mold is used for casting or injection molding a first permanent magnet of a rotor according to an embodiment of the present invention. The mold is hollow, with an outer contour configured as a hollow cylinder. The mold has multiple spacing grooves along the circumference, and the mold is divided into multiple mold subsections by the spacing grooves. The mold subsections have gates located on end faces of the mold and closer to the outer circumference of the mold than to the inner circumference of the mold. The position of the gate corresponds to the position of the gate sprue of the first permanent magnet.

[0094] Figure 13 schematically shows an exploded view of a rotor 1300 for a permanent magnet synchronous motor according to an embodiment of the present invention. Rotor 1300 includes a first permanent magnet 1310 and a second permanent magnet 1320. The first permanent magnet 1310 is configured as a hollow cylinder. In the present invention, the first permanent magnet 1310 being configured as a hollow cylinder particularly means having an outer contour of the first permanent magnet 1310 that is a hollow cylinder. In an embodiment of the present invention, the outer circumferential surface of the first permanent magnet 1310 can be, for example, a closed surface to provide greater structural strength. A plurality of spacing grooves 1330 are arranged circumferentially within the first permanent magnet 1310. The spacing grooves 1330 separate the first permanent magnet 1310 into a plurality of first permanent magnet sub-segments 1311. In an embodiment of the present invention, the spacing grooves 1330 extend axially through the first permanent magnet 1310. The plurality of second permanent magnets 1320 are disposed in, and in particular, inserted into, the spacing grooves 1330. In the present invention, the rotor 1300 has alternating N poles and S poles. These poles are formed at the first permanent magnet sub-section 1311, as shown in Figure 13. The specific magnetic circuit and magnetic field direction will be described in detail later.

[0095] 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.

[0096] In the prior art, permanent magnets in rotors are typically made of high-energy-product materials, such as neodymium iron boron. High-energy-product materials are expensive and have limited magnetization depth. Permanent magnets made of high-energy-product materials are typically placed on a magnetizer in an embedded or surface-mounted manner. Permanent magnets made of high-energy-product materials and rotors having such permanent magnets are typically small in size. In this case, it is necessary to enlarge the stator or increase the stator coils to increase the power of the synchronous motor. In contrast, in the present invention, the first permanent magnet can be made of a low-energy-product material, such as a plastic magnetic material. Plastic magnetic materials are relatively inexpensive. Spacing slots in the first permanent magnet allow for deep orientation and magnetization of the first permanent magnet. Based on these two points, the first permanent magnet can be constructed as large as possible, and a rotor having such a first permanent magnet can provide a stronger magnetic field and more magnetic flux. The rotor according to the present invention can achieve the performance of a rotor made of high-energy-product materials.

[0097] In the prior art, the rotor of a permanent magnet synchronous motor consists of a magnetizer and permanent magnets. The permanent magnets can be attached to the magnetizer's surface to form a surface-mounted rotor, or inserted into the magnetizer to form an embedded rotor. These magnetizers are formed by stamping and stacking silicon steel sheets, making them difficult to manufacture using an integrated molding process.

[0098] Compared with the prior art, a first permanent magnet is used in place of a magnetizer in the rotor according to the present invention. The first permanent magnet according to the present invention is made of plastic magnetic material by injection molding and can be very conveniently prepared through an integrated molding process. Compared with the process of stamping and stacking silicon steel sheets, the integrated molding process of the first permanent magnet is simple in process, high in efficiency, high in precision, and low in 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 magnetizer of silicon steel sheets. Therefore, the magnetization depth of the rotor according to the present invention is deeper, the material utilization rate is higher, and the power density is greater.

[0099] In the present invention, the term "integrated molding" should be understood as the process of completing the entire part molding process in a single mold. Compared to traditional step-by-step manufacturing processes, integrated molding significantly reduces part production costs and offers faster production speeds, enabling the rapid production of a variety of parts, products, and tools. The relatively simple process flow allows the required contours, holes, and surface treatments to be achieved in a single mold, significantly reducing production time and costs while also improving part production accuracy and repeatability. Traditional manufacturing methods require mold and template preparation before the part is processed in separate steps. Integrated molding, however, eliminates the need for additional template preparation and achieves a truly one-step process, significantly improving processing efficiency and speed. Furthermore, molds designed for integrated molding are typically produced in a single process, resulting in extremely rapid production, enabling rapid large-scale production and meeting market demand more quickly. Integrated molding not only meets the needs of traditional manufacturing but can also be applied to high-tech fields such as generators, car washes, and medical devices. In these fields, integrated molding can create more precise and high-quality parts and products.

[0100] The integrally molded first permanent magnet is made of a magnetic material, and preferably a magnetic material with low magnetic resistance and good magnetic permeability can be selected. In an embodiment of the present invention, the first permanent magnet 1310 can be made of, for example, plastic ferrite, for example, molded in one step by an injection molding method. Plastic ferrite has low magnetic resistance, good magnetic permeability, deep magnetization depth, and is suitable for integral molding and industrial production. In an embodiment of the present invention, the plastic ferrite can be, for example, a mixture of nylon and ferrite. 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 while maintaining its volume. Plastic ferrite has a lower density than silicon steel material, which results in a reduced weight of the rotor made of plastic ferrite, thereby improving the power and energy efficiency of the motor. In addition, plastic ferrite has a higher resistivity than silicon steel material, so the rotor made of plastic ferrite can effectively reduce eddy current losses compared to rotors made of silicon steel material.

[0101] Figure 14 shows a cross-sectional view of the first permanent magnet 1310 of the rotor 1300 according to an embodiment of the present invention. In the present invention, multiple positioning holes 1410 are arranged circumferentially within the first permanent magnet 1310. These positioning holes 1410 are positioned between the spacing slots 1330 and the inner circumference of the first permanent magnet 1310. For example, the positioning holes 1410 can be positioned proximate to the rotor sleeve 1420 of the rotor. These positioning holes 1410 extend longitudinally through the first permanent magnet 1310. The positioning holes 1310 are designed so that positioning rods pass through them, connecting the multiple rotors 1300 in series in the longitudinal direction, with the same magnetic poles of the multiple rotors 1300 aligned in the longitudinal direction. Therefore, the positioning holes 1310 can also be referred to as series holes. This is illustrated in more detail in Figures 15 and 16.

[0102] In practical applications, permanent magnet synchronous motors typically have standard dimensions to facilitate their use in different devices and scenarios. These standard dimensions are reflected in a specific radius or shaft center height for the permanent magnet synchronous motor as a whole. If the overall dimensions of the motor are already determined, the rotor diameter or length can be increased to increase the motor's power. However, if the orientation and magnetization depth of the rotor's first permanent magnet remain unchanged, increasing the rotor diameter reduces the utilization rate of the magnetic material. Increasing the orientation and magnetization depth complicates the rotor manufacturing process. In contrast, increasing the rotor length maintains the same utilization rate of the magnetic material, and the process for increasing the rotor length is relatively simple. The rotors according to the present invention can be connected in series in the longitudinal direction. The series-connected rotors have a high aspect ratio, and the overall rotor length can be adjusted based on the number of rotors connected in series. Furthermore, by arranging the positioning holes between the spacing slots and the inner circumference of the first permanent magnets, the positioning holes can avoid the rotor magnetic circuit, thereby not affecting the performance of the rotor and the motor.

[0103] Figure 15 shows a perspective view of rotors 1510 connected in series in the longitudinal direction according to an embodiment of the present invention, and Figure 16 shows a perspective cross-sectional view thereof. Figures 15 and 16 show two rotors 1510 connected in series in the longitudinal direction. In other embodiments, more rotors may be connected in series. Compared to a single rotor, connecting multiple rotors 1510 in series doubles the length of the rotor assembly 1500. Both rotors 1510 have the same structure according to the present invention. The interior of the positioning holes 1410 is smooth, facilitating the insertion and removal of the positioning rods 1520. After connecting the multiple rotors 1510 in series using the positioning rods 1520, the rotor assembly 1500 is pressed onto the rotor shaft, and then the positioning rods 1520 are removed. Because the rotor assembly 1500 and the rotor shaft are tightly fitted, the relative positions of the multiple rotors 1510 do not change after the positioning rods 1520 are removed.

[0104] In an embodiment of the present invention, the number of positioning holes 1410 can, for example, be equal to the number of pole pairs of the rotor 1300 or 1510. This is illustrated with reference to FIG14 . In the embodiment shown in FIG14 , the rotor 1300 or the first permanent magnet 1310 exemplarily has 10 poles, or 5 pole pairs. Five positioning holes 1410 are provided in the first permanent magnet 1310. These five positioning holes 1410 are arranged between the spacing slots 1330 and the inner circumference of the first permanent magnet 1310 and are spaced apart. In other words, positioning holes 1410 are arranged between the first, third, fifth, seventh, and ninth spacing slots and the inner circumference of the first permanent magnet 1310. Furthermore, the positioning holes 1410 are preferably arranged at the line separating adjacent magnetic poles, i.e., the midline between adjacent magnetic poles. In general, the positioning holes 1410 are arranged on the line separating two magnetic poles, running clockwise from the north pole to the south pole along the circumferential direction. In the embodiment shown in FIG. 14 , in the clockwise direction of the circumferential direction, positioning holes 1410 are arranged only on the separation line between the two magnetic poles from the N pole to the S pole, and no positioning holes 1410 are arranged on the separation line between the two magnetic poles from the S pole to the N pole.

[0105] The number of positioning holes is preferably equal to the number of pole pairs, and the positioning holes are evenly distributed in the circumferential direction within the first permanent magnet. After aligning the positioning holes of multiple rotors, the identical magnetic poles of each rotor are precisely aligned in the longitudinal direction, regardless of whether the order of the positioning holes corresponds to each other. This arrangement of positioning holes allows for quick and easy alignment of the magnetic poles of multiple rotors, improving the efficiency of rotor series connection and assembly. Furthermore, the even distribution of the positioning holes does not affect the dynamic balancing performance of the rotors.

[0106] If the locating holes are evenly arranged in the circumferential direction in the first permanent magnet, but the number of locating holes is not equal to the number of pole pairs, for example, the number of pole pairs is 5 and the number of locating holes is 4 or 6, then there is no fixed correspondence between the positions of the locating holes and the positions of the magnetic poles. When multiple rotors are connected in series, the locating holes need to be aligned one by one according to the order of the locating holes, that is, the first locating holes of each rotor are aligned, the second locating holes of each rotor are aligned respectively, and so on. This is the only way to ensure that the same magnetic poles are aligned between each rotor. If the order of the locating holes is misaligned, the same magnetic poles of each rotor will also be misaligned. This arrangement of locating holes increases the complexity of the rotor series connection and greatly affects production efficiency.

[0107] Figures 15 and 16 also show the plastic-encapsulated shell 1530 of the rotor 1510. The plastic-encapsulated shell 1530 surrounds the two end faces of the rotor 1510. The upper and lower end faces of the rotor 1510 can be coated with a polymer material to form the plastic-encapsulated shell 1530, for example. The plastic-encapsulated shell 1530 can prevent the second permanent magnet 1320 from falling off from the spacing groove 1330 of the first permanent magnet 1310, and the plastic-encapsulated shell 1530 can provide additional mechanical strength for the rotor, so that the rotor can adapt to higher speeds. In addition, when multiple rotors 1510 are connected in series, the plastic-encapsulated shell 1530 forms a plastic layer on the end face of the rotor 1510, which can act as a magnetic isolation plate to prevent magnetic leakage.

[0108] During the molding process, the molding material is located on the two axial end faces of the rotor and in the through hole and groove in the middle (not shown). The molding material is placed in a preheating machine for preheating, and the rotor is placed in a mold. The molding process is performed according to pre-set parameters. After the molding is completed, the rotor is inspected to confirm that the molding material completely covers the two end faces of the rotor, and that there are no internal voids or stratifications in the molding layer, and that the appearance of the molding body is defect-free.

[0109] In an embodiment according to the present invention, as shown in Figures 13 and 14 , the cross-sections of the spacing grooves 1330 and the second permanent magnets 1320 can be configured as trapezoids, for example, with the lower base of the trapezoidal cross-section close to the inner circumference of the cross-section of the first permanent magnet 1310, and the upper base of the trapezoidal cross-section close to the outer circumference of the cross-section of the first permanent magnet 1310. Spacing grooves 1330 and second permanent magnets 1320 configured with trapezoidal cross-sections can allow more magnetic fields to pass through the first permanent magnet 1310, thereby reducing magnetic flux leakage.

[0110] In an embodiment according to the present invention, as shown in Figure 14, a positioning portion 1431 can be provided in the spacing groove 1330, for example, and the positioning portion 1431 is used to fix the second permanent magnet 1320 in the spacing groove 1330. In an embodiment according to the present invention, the positioning portion 1431 is arranged in the spacing groove 1330 on one side of the inner circumference of the cross section of the first permanent magnet 1310 close to the first permanent magnet 1310. In an embodiment according to the present invention, the positioning portion 1431 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 1330 of the first permanent magnet 1310 is larger than that of the second permanent magnet 1320, so that the second permanent magnet 1320 can be more easily inserted into the spacing groove 1330. Therefore, it is necessary to provide a positioning portion 1431 to fix the second permanent magnet 1320 in the spacing groove 1330.

[0111] In an embodiment according to the present invention, as shown in FIG14 , an air slot 1432 is provided between the second permanent magnet 1320 disposed in the spacing slot 1330 and the first permanent magnet 1310 on the side facing the inner circumference of the first permanent magnet 1310. Air slot 1432 can, for example, be naturally formed by providing positioning portion 1431. That is, after the second permanent magnet 1320 is inserted into the spacing slot 1330, a gap is formed between the second permanent magnet 1320 and the first permanent magnet 1310 due to the large size of the spacing slot. Because air has very low magnetic permeability, air slot 1432 can reduce magnetic flux leakage. The rotor magnetic path does not extend into the rotor through air slot 1432.

[0112] Figures 17 to 19 illustrate the structure of a rotor according to an embodiment of the present disclosure before plastic packaging, respectively, in a perspective view, a plan view, and an exploded view. In conjunction with Figures 17 to 19, the rotor according to the present disclosure includes a first permanent magnet 171 and a second permanent magnet 172. Specifically, a plurality of spacing slots 1711 are provided on the first permanent magnet 171 to accommodate the second permanent magnet 172 in the corresponding spacing slots 1711, thereby achieving an embedded arrangement of the second permanent magnet. The number of spacing slots 1711 can be 4, 6, 8, 10, 12, etc., and as shown in the figure, there are 10.

[0113] Furthermore, the first permanent magnet is integrally injection-molded from a plastic magnetic material and has a ring-shaped structure symmetrical about a central axis. The plurality of spacing slots 1711 are symmetrically arranged about the central axis and are evenly spaced along the circumferential direction. Each spacing slot 1711 extends axially and may penetrate the first permanent magnet 171 in the axial direction.

[0114] In order to fix the second permanent magnet 172 relative to the first permanent magnet 171, the rotor according to the present disclosure uses a polymer material to plastic-encapsulate the second permanent magnet 172, and in particular, can plastic-encapsulate the two end faces of the first permanent magnet 171 that are opposite in the axial direction. Specifically, as shown in Figures 20-22, the rotor may include a plastic-encapsulated structure 173, which includes two plastic-encapsulated cover portions 1730 covering the two end faces of the first permanent magnet that are opposite in the axial direction. The plastic-encapsulated structure 173 is formed by injection molding and is directly bonded to the first permanent magnet 171 and the second permanent magnet 172. As a result, the two plastic-encapsulated cover portions 1730 fix each second permanent magnet 172 relative to the spacing slot 1711.

[0115] According to the disclosed structure, the rotor, manufactured from plastic magnetic material, does not include an iron core, resulting in a low rotor weight, which reduces the centrifugal force and tensile stress experienced by the rotor during rotation. This makes it particularly suitable for high-speed applications. Furthermore, the rotor is integrally formed through injection molding, simplifying the process and eliminating the need for stacking silicon steel sheets. Furthermore, the rotor is plastic-encapsulated, with the polymer material coating the first and second permanent magnets, providing mechanical strength to the rotor and preventing the second permanent magnet from being thrown off during high-speed rotation, as well as damage and cracking of the plastic-magnetic first permanent magnet.

[0116] In addition, as shown in Figures 20-22, the plastic cover 1730 is provided with a rib 1736 protruding in the axial direction on the side away from the first permanent magnet 171. The rib 1736 has a structure staggered circumferentially and radially, thereby further improving the strength of the plastic cover 1730.

[0117] In order to further increase the strength of the rotor, according to the present disclosure, the rotor is further provided with a hole structure and a slot structure for allowing a polymer material to be filled therein to form a part of the plastic packaging structure, thereby increasing the strength of the rotor.

[0118] Specifically, in conjunction with Figures 17-19 , the rotor according to the present disclosure may include a first through-hole 1741, a second through-hole 1742, and a third through-hole 1743, as well as a first groove 1751 and a second groove 1752. Thus, when a fluid polymer material is injected, the polymer material fills the holes and grooves. Upon solidification, corresponding first filling portions 1731, second filling portions 1732, and third filling portions 1733, as well as first and second ribs 1734 and 1735, are formed. As shown in Figures 20-22 , these components 1731-1735 can all be part of the molded structure 173. Because the molded structure 173 is integrally formed by injection molding, these components 1731-1735 are interconnected by two molded covers 1730. This interconnected structure of multiple components forms the rotor's "second skeleton," providing strong support strength for the first and second permanent magnets 171, 172.

[0119] Furthermore, a first through-hole 1741 is provided on the first permanent magnet 171 and extends axially through both end surfaces of the first permanent magnet 171. Thus, the plastic encapsulation structure may include a first filling portion 1731 that fills the first through-hole 1741. Because the first through-hole 1741 completely penetrates the first permanent magnet 171, the first filling portion 1731 may be connected to the plastic encapsulation cover portion 1730 at both ends, as shown in Figures 20-22. This allows the two plastic encapsulation cover portions 1730 to interact with each other, further increasing the axial strength of the rotor.

[0120] In addition, the rotor includes multiple first through-holes 1741, each of which is disposed between each pair of adjacent spacing slots 1711, as shown in Figures 17-19. This enhances the circumferential strength of the first permanent magnets during rotor rotation, mitigating the strength loss associated with the multiple spacing slots 1711.

[0121] Second through-hole 1742 also axially extends through both end surfaces of first permanent magnet 171. Specifically, second permanent magnet 172 includes an axially extending edge groove 1721, as shown in FIG19 . Thus, a second through-hole is formed between the wall of each spacing groove 1711 and the corresponding edge groove 1721 of second permanent magnet 172, as shown in FIG17-18 . Consequently, molded structure 173 may include a second filling portion 1732 that fills second through-hole 1742. Since second through-hole 1742 completely extends through first permanent magnet 171, second filling portion 1732 can connect to molded cover 1730 at both ends, as shown in FIG20-22 . The setting of the second through hole 1742 allows the second filling portion 1732 to be located in the edge groove 1721 of the second permanent magnet 172. Therefore, when the rotor rotates, the second filling portion 1732 can directly interact with the second permanent magnet 172 in the circumferential direction, thereby reducing the load on the first permanent magnet 171 and improving the overall strength of the rotor.

[0122] The rotor may also include a third through-hole 1743, which also axially extends through both end surfaces of the first permanent magnet 171, as shown in Figures 17-19. Consequently, the molded structure 173 may include a third filling portion 1733 that fills the third through-hole 1743. Because the third through-hole 1743 completely extends through the first permanent magnet 171, the third filling portion 1733 can be connected to the molded cover 1730 at both ends, as shown in Figures 20-22. The third through-hole 1743 is disposed between the wall of each spacing slot 1711 and the corresponding edge slot 1721 of the second permanent magnet 172, thereby further enhancing the rotor's strength.

[0123] In particular, the second through hole 1742 and the third through hole 1743 are positioned at both ends of the spacing slot 1711 in the radial direction. For example, as shown in Figures 17-19, the second through hole 1742 is located at the end away from the central axis, and the third through hole 1743 is located at the end close to the central axis. Through this arrangement, the second filling portion 1732 and the third filling portion 1733 can provide strength support for the second permanent magnet 172 and the first permanent magnet 171 in the radial direction to resist the centrifugal force and tensile stress generated by the rotation, thereby preventing the second permanent magnet from being thrown away and the first permanent magnet from being damaged and cracked when the rotor rotates at high speed. In addition, since the second filling portion 1732 and the third filling portion 1733 are respectively located at both ends of the spacing slot 1711 in the radial direction, the interference with the magnetic field lines of the second permanent magnet 172 is minimized, which is beneficial to the rotor efficiency.

[0124] Furthermore, the rotor may also include a plurality of first grooves 1751 disposed on the first permanent magnet, extending circumferentially on both end faces of the first permanent magnet, as shown in Figures 17-19. Therefore, the molded structure 173 may include first ribs 1734 that fill these first grooves 1751, thereby providing additional strength support for the rotor, particularly the first permanent magnet, at both end faces.

[0125] The rotor may also include multiple second grooves 1752 disposed on each second permanent magnet 172. These grooves 1752 extend circumferentially on two axially opposing second permanent magnet surfaces, as shown in Figures 17-19. Therefore, the molded structure 173 may include second ribs 1735 that fill these second grooves 1752, providing additional strength support for the rotor, particularly the second permanent magnets, at the second permanent magnet surfaces at both ends.

[0126] Each first groove 1751 can be located between each pair of adjacent spacing grooves 1711, and the first grooves 1751 and the second grooves 1752 are staggered in the radial direction, as shown in FIG18 . This allows the first rib 1734 to abut the second permanent magnet 172 at both ends in the circumferential direction, and the second rib 1735 to abut the first permanent magnet 171 at both ends in the circumferential direction. Therefore, when the rotor rotates, the first rib 1734 directly interacts with the second permanent magnet 172 in the circumferential direction, and the second rib directly interacts with the first permanent magnet 171 in the circumferential direction, further increasing the support for the first and second permanent magnets 171, 172 in the circumferential direction and strengthening the rotor.

[0127] Furthermore, each of the two end surfaces of the first permanent magnet includes a first sub-end surface 17121, a second sub-end surface 17122, and a third sub-end surface 17123. First sub-end surface 17121 is located axially at the outermost side of first permanent magnet 171, while second sub-end surface 17122 is axially located between first sub-end surface 17121 and third sub-end surface 17123. First sub-end surface 17121 is radially farther from the central axis than third sub-end surface 17123, while second sub-end surface 17122 is radially located between first sub-end surface 17121 and third sub-end surface 17123. This arrangement saves plastic magnet material during injection molding, increases the volume of the coated polymer material, and enhances mechanical strength.

[0128] As shown in FIG19 , the rotor according to the present disclosure may further include a rotor sleeve 176 for mating with a rotating shaft 177 (shown in FIG22 ). The rotor sleeve is located inside the annular first permanent magnet 171. The first permanent magnet 171 and the rotor sleeve 176 may each have a mating portion for axially abutting against each other to transmit torque, which will not be elaborated on here.

[0129] In this document, unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second" and similar terms used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not necessarily indicate a quantity limitation. Words such as "include" or "comprising" 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.

[0130] The exemplary implementation schemes proposed in the present disclosure are described in detail above with reference to preferred embodiments. However, it will be understood by those skilled in the art that, without departing from the concept of the present disclosure, various modifications and variations can be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the present disclosure can be combined in various ways without exceeding the scope of protection of the present disclosure, which is determined by the appended claims.

Claims

1. An embedded rotor, comprising: a first permanent magnet, wherein the first permanent magnet is configured as a cylinder and is integrally formed, 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-portions by the spacing grooves; a second permanent magnet disposed in the spacing slot; 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.

2. The embedded rotor according to claim 1, wherein: the first permanent magnet sub-portion having a magnetic field direction extending in a radial direction of the first permanent magnet, The first permanent magnet sub-parts 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.

3. The embedded rotor according to claim 1, wherein: The outer circumferential surface of the first permanent magnet is a closed surface, and The spacing groove penetrates the first permanent magnet along the longitudinal direction of the first permanent magnet.

4. The embedded rotor according to claim 1, wherein: The material of the first permanent magnet is plastic ferrite.

5. The embedded rotor according to claim 1, wherein: The second permanent magnet is made of one or more of ferrite, neodymium iron boron, samarium iron nitrogen and samarium cobalt.

6. The embedded rotor according to claim 1, wherein: The cross section of the second permanent magnet is configured as a trapezoid, and The lower base of the trapezoidal cross section is close to the center of the cross section of the first permanent magnet.

7. The inline rotor according to claim 1, wherein: An air slot is provided between the second permanent magnet disposed in the spacing slot and the first permanent magnet on a side facing the central axis of the first permanent magnet.

8. The inline rotor according to claim 1, wherein: The first permanent magnet is integrally cast through a gate, the first permanent magnet sub-portion has a gate tip corresponding to the gate, the gate tip is located at an end surface of the first permanent magnet, and the gate tip is closer to the outer circumference of the first permanent magnet than to the inner circumference of the first permanent magnet.

9. The inline rotor according to claim 8, wherein: Each first permanent magnet sub-section has a respective gate sprue, and the number of the gate sprues is equal to the number of poles of the rotor.

10. The inline rotor according to claim 8, wherein: The gate tip protrudes from the end surface of the first permanent magnet.

11. The inline rotor according to claim 1, wherein: A plurality of positioning holes are arranged in the circumferential direction inside the first permanent magnet, 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; and 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.

12. The inline rotor according to claim 11, wherein: The number of the positioning holes is equal to the number of pole pairs of the rotor, and the positioning holes are arranged on a dividing line between two magnetic poles from the N pole to the S pole in a clockwise direction along the circumferential direction. 13 . The embedded rotor according to claim 1 , comprising a plastic packaging structure comprising two plastic packaging cover portions covering two end surfaces of the first permanent magnet that are opposite in the axial direction and fixing each second permanent magnet relative to the spacing slot.

14. The inline rotor according to claim 13, wherein: The first permanent magnet is provided with a first through hole that penetrates the two end surfaces in the axial direction. The plastic packaging structure is an integrated component and includes a first filling portion that fills the first through hole, and the two plastic packaging covers are connected via the first filling portion. The rotor includes a plurality of first through holes, each of which is arranged between each pair of adjacent spacing slots. The second permanent magnet has an edge groove extending in the axial direction, so that a second through hole penetrating the two end faces is formed between the hole wall of each spacing groove and the corresponding edge groove of the second permanent magnet, the plastic packaging structure includes a second filling portion filling the second through hole, and the two plastic packaging cover portions are connected via the second filling portion. The shapes of the spacing grooves and the second permanent magnets are configured such that a third through hole penetrating the two end faces is provided between the hole wall of each spacing groove and the corresponding second permanent magnet, the plastic packaging structure includes a third filling portion filling the third through hole, and the two plastic packaging covers are connected via the third filling portion, and The second through hole and the third through hole are located at two ends of the spacing slot in the radial direction of the first permanent magnet.

15. The inline rotor according to claim 13, wherein: The first permanent magnet further includes a plurality of first grooves extending along the circumference of the first permanent magnet on the two end surfaces, each first groove being located between each pair of adjacent two spacing grooves. The plastic packaging structure further includes a first rib portion filling the first groove, The second permanent magnet includes two second permanent magnet surfaces facing each other in the axial direction, and the second permanent magnet surfaces include a second groove extending along the circumferential direction of the first permanent magnet. The plastic packaging structure further includes a second rib portion filling the second groove, and The first groove and the second groove are staggered in the radial direction of the first permanent magnet, so that the two ends of the first rib in the circumferential direction of the first permanent magnet respectively abut against the second permanent magnet, and the two ends of the second rib in the circumferential direction of the first permanent magnet respectively abut against the first permanent magnet.

16. The inline rotor according to claim 13, wherein: The plastic cover is provided with a rib protruding in the axial direction on a side facing away from the first permanent magnet.

17. An electric motor comprising the inline rotor according to any one of claims 1 to 16.

18. A method for manufacturing an inline rotor, comprising: The first permanent magnet is integrally manufactured by injection molding, wherein the first permanent magnet is configured as a cylinder and is integrally molded, 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-portions by the spacing grooves; Arranging a first magnetic field applying device in the spacing slot and orienting the first permanent magnet so that the first permanent magnet sub-portions on both sides of the spacing slot have opposite orientations along the radial direction of the first permanent magnet; manufacturing a second permanent magnet; orienting the second permanent magnet so that the second permanent magnet extends along the circumferential direction of the first permanent magnet; placing the second permanent magnet in the spacing slot; as well as The first permanent magnet and the second permanent magnet are magnetized according to the orientation of the first permanent magnet and the orientation of the second permanent magnet, so that the magnetic field of the second permanent magnet in the spacing slot and the magnetic fields of the first permanent magnets on both sides of the spacing slot together form a continuous magnetic circuit with the shortest path.

19. A method for manufacturing an inline rotor, comprising: Manufacturing a first permanent magnet, wherein the first permanent magnet is configured as a cylinder and is integrally formed, 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-portions by the spacing grooves; Arranging a first magnetic field applying device in the spacing slot and orienting the first permanent magnet so that the first permanent magnet sub-portions on both sides of the spacing slot have opposite orientations along the radial direction of the first permanent magnet; magnetizing the first permanent magnet according to the orientation of the first permanent magnet; manufacturing a second permanent magnet; orienting the second permanent magnet so that the second permanent magnet extends along the circumferential direction of the first permanent magnet; magnetizing the second permanent magnet according to the orientation of the second permanent magnet; as well as placing the second permanent magnet in the spacing slot; 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.

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