Rotor assembly and motor

Abstract

The present invention discloses a rotor assembly and an electric motor, wherein the rotor assembly includes a rotor body and at least two magnets; the rotor body includes a main body and an annular portion located on the outer periphery of the main body; the at least two magnets are embedded in the annular portion, and the annular portion is divided into a plurality of sub-diameter portions. The at least two magnets each have a midpoint along the radial direction, and a dividing circle concentric with the axial hole is formed by connecting the midpoints of the at least two magnets, and the dividing circle divides the sub-diameter portion into a proximal area close to the main body and a distal area away from the main body; the sub-diameter portion is provided with a through hole extending along the axial direction of the rotor body, and the through hole is at least partially located in the proximal area of ​​the sub-diameter portion. The rotor assembly of the present invention can reduce the influence of the through hole on the rotor body on the magnetic field of the motor, so as to enhance the magnetic field characteristics of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of drive equipment manufacturing, and in particular to a rotor assembly and an electric motor. Background Art

[0002] Currently, electric motors are widely used as drive devices in the market, especially a type of electric motor called an Interior Permanent Magnet Synchronous Motor (IPM motor for short). The rotor assembly of this type of motor includes a rotor body and a plurality of magnets embedded in the rotor body. These magnets are arranged at intervals along the circumference of the rotor body. The rotor body usually has a through hole between two adjacent magnets. The through hole can be used to reduce weight or allow studs to pass through. In order to obtain a larger torque for the rotor assembly, people usually increase the number of magnets on the rotor body. However, this will cause the position of the rotor body between two adjacent magnets to be reduced, and the magnetic field density between the two adjacent magnets to be enhanced. When the through hole is located in or close to the area with strong magnetic field density, it will destroy the magnetic field at that position, thereby reducing the magnetic field characteristics of the motor, and thus resulting in lower efficiency of the motor. Summary of the Invention

[0003] The main purpose of the present invention is to provide a rotor assembly, which aims to reduce the influence of the through holes on the rotor body on the magnetic field of the motor, thereby enhancing the magnetic field characteristics of the motor and further improving the efficiency of the motor.

[0004] In order to achieve the above-mentioned purpose, the present invention proposes a rotor assembly, which includes a rotor body and at least two magnets; the rotor body includes a main body provided with an axial hole, and an annular portion located on the periphery of the main body and connected to the main body; the at least two magnets are embedded in the annular portion, distributed along the circumference of the rotor body and arranged radially, and the annular portion is divided into a plurality of sub-diameter portions. Wherein, the at least two magnets each have a midpoint along the radial direction, and a dividing circle concentric with the axial hole is formed by connecting the midpoints of the at least two magnets, and the dividing circle divides the sub-diameter portion into a proximal area close to the main body and a distal area away from the main body; the sub-diameter portion is provided with a through hole extending along the axial direction of the rotor body, and the through hole is at least partially located in the proximal area of ​​the sub-diameter portion.

[0005] Optionally, the through hole has a hole diameter along the radial direction of the rotor body and a hole center located at the midpoint of the hole diameter, and the hole center of the through hole is located in the proximal region of the sub-diameter portion.

[0006] Optionally, the through hole has an outer hole edge facing the outer edge of the sub-diameter portion, and the outer hole edge of the through hole is located in a proximal area of ​​the sub-diameter portion.

[0007] Optionally, the through hole has an inner hole edge facing the inner edge of the sub-diameter portion, and the inner hole edge of the through hole is spaced apart from the inner edge of the sub-diameter portion.

[0008] Optionally, the distance between the inner hole edge of the through hole and the inner edge of the sub-diameter portion is equal to the distance between the inner hole edge of the through hole and the boundary circle.

[0009] Optionally, the distance between the center of the through hole and one of the adjacent magnets is equal to the distance between the center of the through hole and another adjacent magnet.

[0010] Optionally, the circumferential portion is formed with a plurality of mounting holes penetrating along the axial direction for mounting the magnets; and a connecting wall connecting two adjacent sub-diameter portions is formed at the outer ends of the mounting holes.

[0011] Optionally, the through hole is a weight-reducing hole; or, the through hole is a screw hole for a stud to pass through.

[0012] Optionally, the rotor assembly further includes an end plate, the end plate covering an end portion of the rotor body, and the end plate and the rotor body are connected by inserting studs into the through holes.

[0013] Optionally, the number of the magnets is greater than or equal to 8 and less than or equal to 14.

[0014] Optionally, the main body of the rotor body is further provided with a plurality of through holes located outside the shaft hole, and the plurality of through holes are arranged at intervals along the outer periphery of the main body.

[0015] Optionally, a partition wall is formed in the main body between two adjacent through holes, and at least a portion of the partition wall corresponds to a portion of the sub-diameter portion and is connected and fixed to the corresponding sub-diameter portion.

[0016] Optionally, the through hole is arranged in any one of a circular, square, and trapezoidal shape.

[0017] The present invention also provides an electric motor, which includes a base, a stator assembly and a rotor assembly; the stator assembly is installed in the base; and the rotor assembly is installed in the stator assembly. The rotor assembly includes a rotor body and at least two magnets; the rotor body includes a main body provided with an axial hole, and an annular portion located on the outer periphery of the main body and connected to the main body; the at least two magnets are embedded in the annular portion, distributed along the circumference of the rotor body and arranged radially, dividing the annular portion into a plurality of sub-diameter portions. The midpoints of the lengths of the at least two magnets in the radial direction are on a dividing circle concentrically arranged with the axial hole, and the dividing circle divides the sub-diameter portion into a proximal area close to the main body and a distal area away from the main body; the sub-diameter portion is provided with a through hole extending along the axial direction of the rotor body, and the through hole is at least partially located in the proximal area of ​​the sub-diameter portion.

[0018] Optionally, the motor is a built-in permanent magnet synchronous motor.

[0019] The technical solution of the present invention is to embed at least two magnets in the annular portion of the rotor body so that the at least two magnets are radially arranged along the circumference of the annular portion, and the annular portion is divided into a plurality of sub-diameter portions. The midpoints of the lengths of the at least two magnets in the radial direction are located on a dividing circle concentrically arranged with the axial hole. The dividing circle divides the sub-diameter portion into a proximal area close to the main body and a distal area away from the main body, and the through hole is at least partially located in the proximal area of ​​the sub-diameter portion, thereby reducing the damage of the through hole to the magnetic field strength around the magnet, reducing the impact on the magnetic field of the motor, and thereby enhancing the magnetic field characteristics of the motor and improving the efficiency of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0021] Figure 1 It is a structural schematic diagram of an embodiment of a rotor assembly of the present invention;

[0022] Figure 2 for Figure 1 Front view of the middle rotor assembly;

[0023] Figure 3 for Figure 2 One of the enlarged images at A in the middle;

[0024] Figure 4 for Figure 2 The second enlarged view of point A in the middle;

[0025] Figure 5 for Figure 1 Schematic diagram of the structure of the middle rotor body;

[0026] Figure 6 for Figure 5 A top view of the middle rotor body;

[0027] Figure 7-A This is a schematic diagram of the structure of the first carrier used in the experiments of the present invention;

[0028] Figure 7-B for Figure 7-A Magnetic field density distribution diagram obtained according to the first carrier experiment;

[0029] Figure 8-A A schematic diagram of the structure of the second carrier used in the experiments of the present invention;

[0030] Figure 8-B for Figure 8-A Magnetic field density distribution diagram obtained from the second carrier experiment;

[0031] Figure 9-A A schematic diagram of the structure of the third vector used in the experiments of the present invention;

[0032] Figure 9-B for Figure 9-A The magnetic field density distribution diagram obtained from the third carrier experiment;

[0033] Figure 10 A magnetic field density distribution diagram formed by the rotor assembly and the stator assembly of the electric motor of the present invention;

[0034] Figure 11-A A schematic diagram of a portion of the structure of a reference motor used in verifying the present invention;

[0035] Figure 11-B for Figure 11-A The circuit voltage-time curve obtained from the reference motor test;

[0036] Figure 12-A A schematic diagram of a portion of the structure of a conventional motor used in verifying the present invention;

[0037] Figure 12-B for Figure 12-A The circuit voltage-time curve obtained from the traditional motor test;

[0038] Figure 13-A A schematic diagram of a portion of the structure of the motor of the present invention used in verifying the present invention;

[0039] Figure 13-B for Figure 13-A A circuit voltage-time graph obtained by testing the motor of the present invention;

[0040] Figure 14 It is a partial structural schematic diagram of the motor of the present invention;

[0041] Figure 15 for Figure 14 Schematic diagram of the structure after the cover is removed.

[0042] Description of Figure Numbers:

[0043]

[0044] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0047] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0048] Electric motors are widely used as drive devices in the market, particularly a type known as an interior permanent magnet synchronous motor (IPM motor). This type of motor generally consists of a stator assembly and a rotor assembly mounted within the stator assembly. The rotor assembly includes a rotor body and multiple magnets embedded in the rotor body, spaced around the rotor body. When current is passed through the coil windings in the stator assembly of an IPM motor, the stator assembly generates a rotating magnetic field, which interacts with the magnetic field of the rotor to produce torque, accelerating the rotor assembly from a stationary state and starting the IPM motor. This type of motor offers advantages such as simple structure, compact size, light weight, and high efficiency, making it widely used in a wide range of fields.

[0049] With the advancement of technology, users have placed higher demands on miniaturization of electric motors. Therefore, people usually set a through hole between two adjacent magnets in the rotor body. This through hole can be used to reduce weight or allow studs to pass through to reduce the weight of the motor. However, in order to obtain greater torque for the rotor assembly, people usually increase the number of magnets on the rotor body. This will result in a smaller area of ​​the rotor body between two adjacent magnets and an increase in the magnetic field density between the two adjacent magnets. When the through hole is located in or close to the area with stronger magnetic field density, it will destroy the magnetic field at that location, reducing the magnetic field characteristics of the motor and thus resulting in lower motor efficiency.

[0050] Based on this, the present invention provides an embodiment of a rotor assembly, which is applied to an electric motor. The rotor assembly can reduce the influence of the through holes on the rotor body on the magnetic field of the electric motor, thereby enhancing the magnetic field characteristics of the electric motor and further improving the efficiency of the electric motor.

[0051] See also Figures 1 to 3In one embodiment of the rotor assembly of the present invention, the rotor assembly includes a rotor body 100 and at least two magnets 200; the rotor body 100 includes a main body 110 provided with an axial hole 111, and an annular portion 120 located on the outer periphery of the main body 110 and connected to the main body 110; the at least two magnets 200 are embedded in the annular portion 120, distributed along the circumference of the annular portion 120 and arranged radially, and the annular portion 120 is divided into a plurality of sub-diameter portions 121. In which, the at least two magnets 200 have a midpoint 201 of their length in the radial direction, and a dividing circle S1 concentrically arranged with the axial hole 111 is formed by connecting the midpoint 201 of the at least two magnets 200. The dividing circle S1 divides the sub-diameter portion 121 into a proximal area 121a close to the main body 110 and a distal area 121b away from the main body 110; the sub-diameter portion 121 is provided with a through hole 124 extending along the axial direction of the rotor body 100, and the through hole 124 is at least partially located in the proximal area 121a of the sub-diameter portion 121.

[0052] Specifically, the rotor body 100 is an iron core composed of multiple thin iron plates stacked and fastened in the axial direction. The main body 110 of the rotor body 100 is provided with an axial hole 111, which is suitable for allowing a rotating shaft to pass through and connect, so that after the rotor assembly is assembled into the motor, the rotor assembly drives the rotating shaft to rotate, thereby driving the driven object to rotate. The circumferential portion 120 of the rotor body 100 is embedded with at least two magnets 200. The at least two magnets 200 are arranged at intervals along the circumferential portion 120 of the rotor body 100 and extend radially, so that these magnets 200 are radially arranged in the circumferential portion 120 of the rotor body 100. The magnets 200 are preferably permanent magnets.

[0053] The circumferential portion 120 of the rotor body 100 is divided into sub-diameter portions 121 by two adjacent magnets 200, and each sub-diameter portion 121 is roughly fan-shaped. Each of the sub-diameter portions 121 is provided with a through hole 124 extending along the axial direction of the rotor body 100. The through hole 124 can be a weight-reducing hole or a screw hole for screws to pass through. Each of the sub-diameter portions 121 is divided into a proximal area 121a and a distal area 121b by a dividing circle S1 concentrically arranged with the axial hole 111; wherein, the proximal area 121a is close to the main body 110; and the distal area 121b is far away from the main body 110. Figure 2 S1 in the figure represents a dividing circle; S2 represents an inner circumference formed by connecting the inner edges of the plurality of sub-diameter portions 121 and concentric with the shaft hole 111 (also an inner circumference formed by connecting the inner end edges of the plurality of magnets 200); Figure 3L in the figure represents the radial length of the magnet 200 along the rotor body 100. Therefore, the through hole 124 is located in the proximal region 121a of the sub-diameter portion 121, that is, between the boundary circle S1 and the inner circumference S2. It should be noted that the boundary circle S1 and the inner circumference S2 are both virtual circles.

[0054] In the related traditional technology, since the distal region 121b of the sub-diameter portion 121 has a large area, the through hole 124 is usually set in the distal region 121b of the sub-diameter portion 121. However, the applicant has found that setting the through hole 124 in the distal region 121b of the sub-diameter portion 121 tends to reduce the magnetic field characteristics of the motor and reduce the efficiency of the motor. Therefore, in order to obtain a better position for opening the through hole 124 on the rotor body 100 of the rotor assembly, the applicant has studied and analyzed the position of the through hole 124 on the rotor body 100. Figure 7-A to Figure 9-B As shown, the research objects are three carriers simulating the rotor body 100, namely the first carrier 10, the second carrier 20, and the third carrier 30; the only difference between the three carriers is that the first carrier 10 has no hollow area, the second carrier 20 has a hollow area 21, and the third carrier 30 has a hollow area 31 (the volume of the hollow area 31 provided in the third carrier 30 is larger than the volume of the hollow area 21 of the second carrier 20); wherein, the hollow areas (21 and 31) are hollow structures (such as the shaft hole 111 or the through hole 112, etc.) formed by the main body 110 of the simulation rotor body 100 for accommodating air.

[0055] The above three vectors were tested under the same experimental conditions, and the following conclusions were drawn after research and analysis:

[0056] See also Figure 7-A and Figure 7-B For the first carrier 10, which has no hollow area, the magnetic field generated by the two magnets 200 embedded in the first carrier 10 forms the smallest magnetic flux at position P1, which is located at or near the midpoint of the line connecting the midpoints of the two magnets 200 in the longitudinal direction. In other words, the magnetic field intensity generated by the two magnets 200 embedded in the first carrier 10 is at or near the midpoint of the line connecting the midpoints of the two magnets 200 in the longitudinal direction (i.e., position P1).

[0057] See also Figure 8-A and Figure 8-BRegarding the second carrier 20, a hollow area 21 is provided on the second carrier 20. The magnetic field generated by the two magnets 200 embedded in the second carrier 20 forms the smallest magnetic flux at position P2. Relative to the first carrier 10, position P2 of the second carrier 20 is offset from position P1 toward the hollow area 21. In other words, the position where the magnetic field strength generated by the two magnets 200 embedded in the second carrier 20 is weakest is affected by the hollow area 21 and shifts toward the hollow area 21.

[0058] See also Figure 9-A and Figure 9-B The third carrier 30 has a hollow area 31 located at the position of the second carrier 20. The volume of the hollow area 31 on the third carrier 30 is larger than the volume of the hollow area 21 on the second carrier 20. The magnetic field generated by the two magnets 200 embedded in the third carrier 30 forms the smallest magnetic flux at position P3. Compared to the third carrier 30, position P3 of the third carrier 30 is offset from position P2 toward the hollow area. In other words, since the hollow area of ​​the third carrier 30 is larger than that of the second carrier 20, the position where the magnetic field strength generated by the two magnets 200 on the third carrier 30 is weakest is more affected by the hollow area and continues to shift toward the hollow area.

[0059] The applicant has concluded through the above experimental analysis that the rotor body 100 has a hollow area formed in the main body 110 of the rotor body 100 due to the provision of a hollow structure such as an axial hole 111 or other through-hole 112 in the main body 110 of the rotor body 100. Therefore, the magnetic field generated by the magnet 200 on the rotor body 100 is affected by the hollow area on the main body 110 of the rotor body 100, causing the position where the magnetic field strength of the magnet 200 is weakest to shift from the sub-diameter portion 121 of the rotor body 100 from the outside to the inside (e.g., Figure 10 As shown in FIG, the magnetic field strength in the distal region 121b of the sub-diameter portion 121 is relatively strong, while the magnetic field strength in the proximal region 121a of the sub-diameter portion 121 is relatively weak. In other words, the position P0 of the weak magnetic field strength formed by the magnet 200 is located in the proximal region 121a. Therefore, in the embodiment of the rotor assembly of the present invention, compared with setting the through hole 124 as a whole in the distal region 121b of the sub-diameter portion 121, setting the through hole 124 at least partially in the proximal region 121a of the sub-diameter portion 121 can effectively reduce the damage of the through hole 124 to the magnetic field strength around the magnet 200, thereby reducing the impact on the magnetic field of the motor, enhancing the magnetic field characteristics of the motor, and further improving the efficiency of the motor.

[0060] The technical solution of the present invention is to embed at least two magnets 200 in the annular portion 120 of the rotor body 100 so that the at least two magnets 200 are radially arranged along the circumference of the annular portion 120, and the annular portion 120 is divided into a plurality of sub-diameter portions 121. The midpoints of the lengths of the at least two magnets 200 in the radial direction are located on a dividing circle S1 concentrically arranged with the axial hole 111. The dividing circle S1 divides the sub-diameter portion 121 into a proximal area 121a close to the main body 110 and a distal area 121b away from the main body 110, and the through hole 124 is at least partially located in the proximal area 121a of the sub-diameter portion 121, thereby reducing the damage of the through hole 124 to the magnetic field strength around the magnet 200, reducing the impact on the magnetic field of the motor, and thereby enhancing the magnetic field characteristics of the motor and improving the efficiency of the motor (see the above introduction for details).

[0061] In order to verify the working performance of the motor equipped with the rotor assembly of the present invention, the motor was tested. The test subjects were three types of motors, namely a reference motor, a conventional motor, and the motor of the present invention. The rotor body 100 of the rotor assembly of the reference motor did not have a through hole in its sub-diameter portion 121 (such as Figure 12-A The rotor body 100 of the rotor assembly of the conventional motor has a through hole 123 (such as Figure 13-A As shown); The rotor body 100 of the rotor assembly of the motor of the present invention is provided with a through hole 123 (as shown) in the proximal region 121a of the sub-diameter portion 121. Figure 14 -A). The three motors mentioned above were tested under the same experimental conditions, and the obtained data were plotted respectively. Figure 12-B 、 Figure 13-B 、 Figure 14 -B shows the loop voltage-time curve; at the same time, the data obtained from the experiment are sorted out to obtain the following Table 1.

[0062] As can be seen from Table 1 below, the induced voltage of the conventional motor is significantly reduced compared to the reference motor, by at least 7.87% to -9.7%. This indicates that the through-holes in the distal region of the sub-diameter portion significantly affect the magnetic field, resulting in poor magnetic field characteristics in the conventional motor. However, the induced voltage of the motor of the present invention is not significantly reduced compared to the reference motor, by less than 0.4%, a negligible reduction. This shows that the motor of the present invention, by providing through-holes in the proximal region of the sub-diameter portion of the rotor body, can reduce the damage caused by through-holes 124 to the magnetic field strength around magnet 200, reduce the impact on the motor's magnetic field, and thereby enhance the motor's magnetic field characteristics and improve motor efficiency.

[0063] Table 1: Comparison of test results of different types of motors

[0064]

[0065] See also Figure 2 and Figure 3 In one embodiment, the through hole 124 has a diameter along the radial direction of the rotor body 100 and a hole center 1243 located at the midpoint of the diameter. The hole center 1243 of the through hole 124 is located within the proximal region 121a of the sub-diameter portion 121. This ensures that more than half of the volume of the through hole 124 falls within the proximal region 121a of the radial portion, effectively reducing the impact of the through hole 124 on the magnetic field strength around the magnet 200 and significantly enhancing the magnetic field characteristics of the motor. It is worth mentioning that the cross-section of the through hole 124 can be a regular circle or an ellipse. If the cross-section of the through hole 124 is circular, the hole center 1243 of the through hole 124 is the center of the circle. If the cross-section of the through hole 124 is elliptical, the hole center 1243 of the through hole 124 is the intersection of the major axis and the minor axis of the ellipse.

[0066] Of course, in other embodiments, the cross-section of the through hole 124 can also be configured in a teardrop shape, such that the cross-section of the through hole 124 comprises a main hole region with a larger hole area and a side hole region with a smaller hole area. In this way, the side hole region of the through hole 124 can be correspondingly positioned in the proximal region 121a of the sub-diameter portion 121, while the main hole region of the through hole 124 can at least partially correspond to the proximal region 121a of the sub-diameter portion 121. In this case, the hole center 1243 of the through hole 124 is the midpoint of the longest distance from the edge of the side hole region to the main hole region. This design not only reduces the damage caused by the through hole 124 to the magnetic field strength around the magnet 200 and enhances the magnetic field characteristics of the motor, but also maximizes the use of the space within the sub-diameter portion 121 to expand the volume of the through hole 124, significantly reducing the weight of the rotor body 100.

[0067] See also Figure 2 and Figure 3 In one embodiment, the through hole 124 has an outer edge 1241 facing the outer edge of the sub-diameter portion 121. The outer edge 1241 of the through hole 124 is located within the proximal region 121a of the sub-diameter portion 121. In this way, the through hole 124 is entirely located within the proximal region 121a of the sub-diameter portion 121. In other words, the through hole 124 is entirely located at a location where the magnetic field of the magnet 200 is relatively weak, so that the through hole 124 does not easily interfere with the magnetic field strength of the distal region 121b of the sub-diameter portion 121.

[0068] Considering that, although the magnetic field strength in the proximal region 121a of the sub-diameter portion 121 is relatively weak compared to the distal region 121b of the sub-diameter portion 121, since the inner edge of the sub-diameter portion 121 is closer to the ends of two adjacent magnets 200, a location with a larger magnetic flux in the proximal region 121a of the sub-diameter portion 121 is formed at the inner edge of the sub-diameter portion 121. In view of this, the through hole 124 optionally has an inner hole edge 1242 facing the inner edge of the sub-diameter portion 121, and the inner hole edge 1242 of the through hole 124 is spaced apart from the inner edge of the sub-diameter portion 121. Such a design allows the through hole 124 to be located on the side of the pericentric area 121a of the sub-diameter portion 121 close to the dividing circle S1, so that the through hole 124 is spaced a distance from the inner edge of the sub-diameter portion 121, ensuring that most of the hole area of ​​the through hole 124 is located at the position with the weakest magnetic field strength in the pericentric area 121a of the sub-diameter portion 121, greatly reducing the damage of the through hole 124 to the magnetic field strength around the magnet 200, and greatly enhancing the magnetic field characteristics of the motor.

[0069] Furthermore, the distance between the inner hole edge 1242 of the through hole 124 and the inner edge of the sub-diameter portion 121 is equal to the distance between the inner hole edge 1242 of the through hole 124 and the boundary circle S1. Figure 3 As shown, d1 represents the distance between the inner edge 1242 of the through hole 124 and the inner edge of the sub-diameter portion 121; d2 represents the distance between the inner edge 1242 of the through hole 124 and the boundary circle S1. Therefore, d1 = d2. To maximize the volume of the through hole 124, the outer edge 1241 of the through hole 124 is brought close to the boundary circle S1. Thus, the distance between the inner edge 1242 of the through hole 124 and the boundary circle S1 is the diameter of the through hole 124. That is to say, the distance between the inner hole edge 1242 of the through hole 124 and the inner edge of the sub-diameter portion 121 is equal to the hole diameter, so that the through hole 124 as a whole is exactly located at the position where the magnetic field strength is weakest in the proximal area 121a of the sub-diameter portion 121. In this way, the area of ​​the proximal area 121a can be utilized to open a through hole 124 with a larger volume as much as possible, and it can also ensure that the through hole 124 will not cause significant damage to the magnetic field strength around the magnet 200, thereby effectively enhancing the magnetic field characteristics of the motor.

[0070] Furthermore, the distance between the hole center 1243 of the through hole 124 and one of the adjacent magnets 200 is equal to the distance between the hole center 1243 of the through hole 124 and another adjacent magnet 200. Assuming that the two magnets 200 located on both sides of the sub-diameter portion 121 are the first magnet and the second magnet respectively; Figure 4 As shown, Figure 4Here, d3 represents the distance between the center 1243 of the through hole 124 on the sub-diameter portion 121 and the first magnet; d4 represents the distance between the center 1243 of the through hole 124 and the second magnet. Therefore, d3 = d4. This allows the through hole 124 to be located in the middle of the near-center region 121a of the sub-diameter portion 121. This not only reduces the impact of the through hole 124 on the magnetic field around the magnet 200, but also ensures that the strength of the sub-diameter portion 121 around the through hole 124 is substantially consistent, resulting in a similar stress distribution. This prevents deformation of the sub-diameter portion 121 in the near-center region 121a due to localized insufficient strength.

[0071] See also Figure 1 and Figure 2 Based on any of the above embodiments, as described above, the through hole 124 can be a weight-reducing hole; or, the through hole 124 can be a screw hole for the stud 310 to pass through (the stud 310 can refer to Figure 14 Specifically, in this embodiment, each of the sub-diameter portions 121 is provided with a through hole 124 in its proximal region 121a, and the through hole 124 is a weight-reducing hole. The through hole 124 extends from one end surface of the sub-diameter portion 121 of the rotor body 100 along the axial direction of the rotor body 100 to the other end surface of the sub-diameter portion 121.

[0072] In one embodiment, the rotor assembly further includes an end plate 300 (the end plate 300 can be seen in Figure 14 ), the end plate 300 covers the end of the rotor body 100, and the end plate 300 and the rotor body 100 are connected by inserting the stud 310 into the through hole 124. In this way, the end surface of the rotor body 100 is covered by the end plate 300, so that there is no need to open additional screw holes on the rotor body 100, which reduces the interference with the magnetic field on the rotor assembly and helps to enhance the magnetic field characteristics of the motor. Specifically, the end of the through hole 124 close to the end surface of the rotor body 100 can be used for the screw to be inserted, so that the screw connects and fixes the rotor body 100 and the end plate 300; the rest of the through hole 124 is in a hollow state, which is used to reduce weight.

[0073] See also Figure 2 、 Figure 5 and Figure 6Optionally, the annular portion 120 is formed with a plurality of mounting holes 123 extending axially therethrough for mounting the magnets 200; a connecting wall 122 connecting two adjacent sub-diameter portions 121 is formed at the outer ends of the mounting holes 123. Specifically, the plurality of mounting holes 123 are radially arranged along the annular portion 120; each mounting hole 123 is arranged in a long strip shape, and each mounting hole 123 is mounted with one magnet 200. To improve the stability of the installation of the magnet 200, a connecting wall 122 connecting two adjacent sub-diameter portions 121 is formed at the outer ends of the mounting holes 123. The connecting wall 122 confines the magnet 200 within the mounting hole 123, making it difficult for the magnet 200 to fall out of the mounting hole 123 radially outward from the rotor body 100, thereby effectively improving the stability of the installation of the magnet 200.

[0074] Please continue reading Figure 2 、 Figure 5 and Figure 6 Based on any of the above embodiments, the main body 110 of the rotor body 100 is further provided with a plurality of through-holes 112 located outside the axial hole 111, and the plurality of through-holes 112 are arranged at intervals along the outer periphery of the main body 110. The plurality of through-holes 112 are suitable for reducing the weight of the rotor body 100 or for magnetic isolation. Specifically, the through-holes 112 extend from one end face of the main body 110 of the rotor body 100 along the axial direction of the rotor body 100 to the other end face thereof, and one side of the through-holes 112 passes through the outer edge of the main body 110 and communicates with the mounting hole 123.

[0075] Furthermore, the main body 110 forms a partition wall 113 between two adjacent through-holes 112. At least a portion of the partition wall 113 corresponds to a portion of the sub-diameter portion 121 and is fixedly connected to the corresponding sub-diameter portion 121. The main body 110, the partition wall 113, and the radial portion are integrally formed. The shape of the through-hole 112 can be designed in a variety of ways, and is not limited here. For example, but not limited to, the through-hole 112 can be any of a circular, square, or trapezoidal shape.

[0076] See also Figure 2 and Figure 6 Based on any of the above embodiments, in the related conventional art, the through-holes 124 have a significant impact on the magnetic field of the rotor assembly. Therefore, the number of magnets 200 is reduced, and the spacing between two adjacent magnets 200 is increased, thereby weakening the magnetic field strength between the two adjacent magnets 200 and reducing the impact of the through-holes 124 on the magnetic field of the rotor assembly. Therefore, the number of magnets 200 typically configured in the rotor assembly in the related conventional art does not exceed six.

[0077] In this embodiment, because the through-hole 124 is positioned between two adjacent magnets 200, where the magnetic field strength is relatively weak, the through-hole 124 has a relatively small impact on the magnetic field of the rotor assembly, thereby allowing the number of magnets 200 to be appropriately increased. Therefore, optionally, the number of magnets 200 is greater than or equal to 8 and less than or equal to 14. For example, but not limited to, the number of magnets 200 is 8, 10, 12, or 14. Optionally, the plurality of magnets 200 are arranged symmetrically about one diameter of the rotor body 100.

[0078] See also Figure 14 and Figure 15 The present invention further provides an electric motor comprising a base, a stator assembly 400, and a rotor assembly. The stator assembly 400 is mounted within the base, and the rotor assembly is mounted within the stator assembly 400. The specific structure of the rotor assembly is similar to that of the aforementioned embodiments. Since this electric motor utilizes all the technical solutions of all the aforementioned embodiments, it also possesses all the beneficial effects brought about by the technical solutions of the aforementioned embodiments, and therefore will not be further elaborated here.

[0079] Specifically, the stator assembly 400 includes a stator body 410 and coil windings disposed within the stator body 410. The rotor assembly is mounted within the coil windings, wrapping around the outer circumference of the rotor assembly. When assembling the motor, the motor's shaft is inserted into the shaft hole 111 of the rotor assembly and secured. The rotor assembly is then installed within the stator assembly 400. Finally, the stator assembly 400 and the rotor assembly are mounted together within the motor base, completing the complete motor assembly.

[0080] When the motor is powered on, alternating current is input into the coil winding, causing the stator body 410 to generate a rotating magnetic field. The rotating magnetic field interacts with the magnetic field generated by the rotor assembly, so that the rotor assembly is driven to rotate under the interaction of the magnetic field, and then the rotor assembly drives the motor shaft to rotate, thereby starting the motor and starting the motor to work.

[0081] Optionally, the motor is an interior permanent magnet synchronous motor (IPM motor for short).

[0082] Compared to the reference motor, the motor of the present invention exhibits a negligible reduction in induced voltage, less than 0.4% (see Table 1 above). This reduction is insignificant. This suggests that the motor of the present invention, by providing a through hole in the proximal region of the rotor body at its sub-diameter portion, can reduce the impact of the through hole 124 on the magnetic field strength surrounding the magnet 200, thereby reducing the impact on the motor's magnetic field, thereby enhancing the motor's magnetic field characteristics and improving its efficiency.

[0083] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A rotor assembly, characterized in that: The rotor assembly comprises: a rotor body, the rotor body comprising a main body portion having an axial hole, and a circumferential portion located at an outer periphery of the main body portion and connected to the main body portion; and At least two magnets are embedded in the circumferential portion and distributed along the circumference of the rotor body in a radial arrangement, dividing the circumferential portion into a plurality of sub-diameter portions; The at least two magnets each have a midpoint along the radial direction, and a dividing circle concentric with the axial hole is formed by connecting the midpoints of the at least two magnets, and the dividing circle divides the sub-diameter portion into a proximal area close to the main body and a distal area far from the main body; The sub-diameter portion is provided with a through hole extending along the axial direction of the rotor body, and the through hole is at least partially located in the proximal area of ​​the sub-diameter portion; the through hole has an inner hole edge closest to the inner edge of the sub-diameter portion, and the inner hole edge of the through hole is spaced apart from the inner edge of the sub-diameter portion; the distance between the inner hole edge of the through hole and the inner edge of the sub-diameter portion is equal to the distance between the inner hole edge of the through hole and the dividing circle.

2. The rotor assembly according to claim 1, wherein: The through hole has a hole diameter along the radial direction of the rotor body and a hole center located at the midpoint of the hole diameter, and the hole center of the through hole is located in the near-center area of ​​the sub-diameter portion.

3. The rotor assembly according to claim 2, wherein: The through hole has an outer hole edge close to the outer edge of the sub-diameter portion, and the outer hole edge of the through hole is located in a proximal area of ​​the sub-diameter portion.

4. The rotor assembly according to any one of claims 2 to 3, wherein: The distance between the center of the through hole and one of the adjacent magnets is equal to the distance between the center of the through hole and another adjacent magnet.

5. The rotor assembly according to any one of claims 1 to 3, wherein: The circumferential portion is formed with a plurality of mounting holes penetrating along the axial direction for mounting the magnets; and the outer ends of the mounting holes are formed with connecting walls connecting two adjacent sub-diameter portions.

6. The rotor assembly according to any one of claims 1 to 3, wherein: The through hole is a weight-reducing hole; or, the through hole is a screw hole for a stud to pass through.

7. The rotor assembly according to claim 6, wherein: The rotor assembly further includes an end plate covering an end portion of the rotor body, wherein the end plate and the rotor body are connected by inserting studs into the through holes.

8. The rotor assembly according to any one of claims 1 to 3, wherein: The number of the magnets is greater than or equal to 8 and less than or equal to 14.

9. The rotor assembly according to any one of claims 1 to 3, wherein: The main body of the rotor body is further provided with a plurality of through holes located outside the shaft hole, and the plurality of through holes are arranged at intervals along the outer periphery of the main body.

10. The rotor assembly according to claim 9, wherein: The main body is provided with a partition wall between two adjacent through holes, and at least a portion of the partition wall corresponds to a portion of the sub-diameter portion and is connected and fixed to the corresponding sub-diameter portion.

11. The rotor assembly according to claim 10, wherein: The through hole is arranged in any one of a circular, square and trapezoidal shape.

12. An electric motor, characterized in that: The electric motor comprises: base; a stator assembly, the stator assembly being installed in the base; and The rotor assembly according to any one of claims 1 to 11, wherein the rotor assembly is installed in the stator assembly.

13. The electric motor according to claim 12, wherein The motor is a built-in permanent magnet synchronous motor.

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