A rotor core for a brushless motor, a rotor, and a brushless motor

Abstract

This invention relates to a rotor core for a brushless motor, a rotor, and a brushless motor. The rotor core includes a core support, multiple rotor core segments, and multiple magnetic bridges. The multiple rotor core segments are spaced apart circumferentially along the core support, and each rotor core segment is connected to the core support via a magnetic bridge. Spaces for accommodating magnets are formed between adjacent rotor core segments, and these spaces are spaced apart from the core support. The cross-sectional shape of the magnetic bridge perpendicular to the rotation axis is S-shaped. This invention is based on connecting the rotor core segments and the core support with magnetic bridges, and forming spaces between adjacent rotor core segments to accommodate magnets. This creates spaces between the magnets and the core support, forming magnetic isolation grooves to reduce magnetic leakage. The S-shaped cross-sectional shape of the magnetic bridge further reduces magnetic leakage compared to a straight magnetic bridge structure. The S-shape also has deformability, absorbing displacement and deformation, reducing peak stress, resulting in a more uniform stress distribution and reducing stress concentration.

Description

Technical Field

[0001] This invention relates to the field of motor equipment technology, and in particular to a rotor core, rotor, and brushless motor for a brushless motor. Background Technology

[0002] The rotor of a brushless DC motor is the core rotating component, primarily composed of permanent magnets. Its function is to interact with the rotating magnetic field generated by the stator, thereby achieving continuous rotor rotation. Depending on the structure and application, rotors can be mainly divided into two types: internal rotors and external rotors. Internal rotor brushless motors refer to a structure where the rotor (permanent magnet part) is located at the center of the motor, and the stator (winding part) surrounds it on the outside. Tangential internal rotors are a common rotor type. The biggest problem faced by tangential rotor structures is relatively high magnetic leakage. When the magnetic flux bypasses the air gap and forms a loop directly in the rotor core yoke, it results in low utilization of the permanent magnets and a decline in motor performance. These problems urgently need to be solved. Summary of the Invention

[0003] This invention discloses a rotor core, rotor, and brushless motor for a brushless motor, aiming to solve the technical problems existing in the prior art.

[0004] The present invention adopts the following technical solution: In a first aspect, the present invention provides a rotor core for a brushless motor, the rotor core comprising a core support, a plurality of rotor core segments and a plurality of magnetic bridges; the plurality of rotor core segments are spaced apart circumferentially along the core support, and each rotor core segment is connected to the core support via the magnetic bridges, a space for accommodating magnets is formed between adjacent rotor core segments, and the space is spaced apart from the core support; the cross-sectional shape of the magnetic bridge perpendicular to the axial direction is "S" shaped.

[0005] In the rotor core of the brushless motor of the present invention, the cross-sectional width of the magnetic bridge is W, 1mm≤W≤1.4mm; and / or, the length of the S-shaped cross-section of the magnetic bridge is L, L=(1.03-1.07)L1, where L1 is the radial distance between the end of the rotor core lobe and the core support.

[0006] In the rotor core of the brushless motor of the present invention, W is 1.2 mm; and / or L = 1.05L1.

[0007] In the rotor core of the brushless motor of the present invention, the rotor core includes a core body; the outer ends of the core body protrude outwards on both sides to form a first limiting strip and a second limiting strip, and the inner ends of the core body protrude outwards on both sides to form a third limiting strip and a fourth limiting strip; a first through groove is formed at the corner where the first limiting strip and the core body connect; the minimum distance between the first through groove and the outer surface of the core body is H1, 0.5mm≤H1≤0.7mm, and / or, a second through groove is formed at the corner where the second limiting strip and the core body connect; the minimum distance between the second through groove and the outer surface of the core body is H2, 0.5mm≤H2≤0.7mm.

[0008] In the rotor core of the brushless motor of the present invention, H1 and H2 are equal, both being 0.6 mm.

[0009] In the rotor core of the brushless motor of the present invention, the cross-sectional shape of the first through slot includes a first arc segment and a second arc segment; one end of the first arc segment is connected to one end of the second arc segment, and the other end intersects with the first limiting strip; the other end of the second arc segment intersects with the core body, and the curvature of the second arc segment is smaller than that of the first arc segment; and / or, the cross-sectional shape of the second through slot includes a third arc segment and a fourth arc segment; one end of the third arc segment is connected to one end of the fourth arc segment, and the other end intersects with the second limiting strip; the other end of the fourth arc segment intersects with the core body, and the curvature of the fourth arc segment is smaller than that of the third arc segment.

[0010] In the rotor core of the brushless motor of the present invention, the angle between the tangent at the midpoint of the first arc segment and the first side of the first limiting strip is β1, 140°≤β1≤150°; and / or, the angle between the tangent at the midpoint of the third arc segment and the second side of the second limiting strip is β2, 140°≤β2≤150°.

[0011] In the rotor core of the brushless motor of the present invention, the included angle β1 and the included angle β2 are equal, both being 145°.

[0012] In the rotor core for a brushless motor of the present invention, a through slot is provided on one or both sides of the rotor core lobe.

[0013] In a second aspect, the present invention also provides a rotor for a brushless motor, the rotor comprising any of the rotor cores described above, a plurality of magnets and a rotating shaft; the magnets are disposed within a space formed between adjacent rotor core segments for accommodating the magnets; the rotating shaft is mounted on the rotor core.

[0014] In the rotor of the brushless motor of the present invention, the magnet is made of ferrite.

[0015] In a third aspect, the present invention also provides a brushless motor comprising any of the rotor cores or rotors described above.

[0016] The brushless motor of the present invention also includes a stator, a housing, and a stator coil; the stator coil is made of enameled aluminum wire.

[0017] In the brushless motor of the present invention, the cross section of the stator perpendicular to the axis is a rectangle with an arc-shaped chamfer.

[0018] The brushless motor of the present invention further includes a speed reducer and a fan blade; the speed reducer is disposed on one side of the housing and is drivenly connected to the rotor; the fan blade is disposed on the other side of the housing and is drivenly connected to the rotor.

[0019] The technical solution adopted in this invention can achieve the following beneficial effects: This invention mainly provides a rotor core for a brushless motor. It is based on connecting the rotor core segments and the core support with a magnetic bridge, and forming a space between adjacent rotor core segments to accommodate magnets. This space between the magnets and the core support forms a magnetic isolation groove to reduce magnetic leakage. The cross-sectional shape of the magnetic bridge is defined as S-shaped, which not only further reduces magnetic leakage compared to a straight magnetic bridge structure, but also has deformability, which can absorb displacement and deformation, reduce peak stress, make the stress distribution more uniform, and reduce stress concentration. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 This is a schematic diagram of the structure of a rotor core for a brushless motor according to the present invention; Figure 2 For the present invention Figure 1 A magnified schematic diagram of the local structure at point A; Figure 3 For the present invention Figure 1 A magnified schematic diagram of the local structure at point B; Figure 4 For the present invention Figure 1 A magnified schematic diagram of the structure at point C in the middle; Figure 5 This is a schematic diagram of the structure of a rotor for a brushless motor according to the present invention; Figure 6 This is one of the structural schematic diagrams of a brushless motor according to the present invention; Figure 7 This is a second schematic diagram of the structure of a brushless motor according to the present invention; Figure 8 This is a schematic diagram of the stator structure of a brushless motor according to the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. Rotor; 11. Rotor core; 13. Shaft; 111. Core support; 112. Rotor core segment; 1121. Core body; 1122. First limiting bar; 11221. First side; 1123. Second limiting bar; 11231. Second side; 1124. Third limiting bar; 1125. Fourth limiting bar; 1126. First through slot; 11261. First arc segment; 11 262. Second arc segment; 1127. Second through slot; 11271. Third arc segment; 11272. Fourth arc segment; 1128. Through slot; 113. Magnetic bridge; 12. Magnet; 13. Shaft; 2. Stator; 21. Tooth; 22. Yoke; 3. Housing; 31. Front end cover; 32. Rear end cover; 33. Stator housing; 4. Stator coil; 5. Reducer; 6. Fan blade; 7. Bushing. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a magnetic connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, "a plurality of" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0024] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] To address the problems existing in the prior art, this application provides a rotor core for a brushless motor, a rotor, and a brushless motor.

[0026] Example 1 This embodiment provides a rotor core for a brushless motor, such as... Figure 1 and Figure 2 As shown, the rotor core 11 includes a core support 111, multiple rotor core segments 112, and multiple magnetic bridges 113. The multiple rotor core segments 112 are arranged circumferentially along the core support 111. If they are arranged at equal intervals, they form an internal tangential rotor. Each rotor core segment 112 is connected to the core support 111 through a magnetic bridge 113. A space for accommodating magnets is formed between adjacent rotor core segments 112. There is a gap between the space and the core support 111, that is, there is a gap between the magnet and the core support 111. Air is contained in the gap, forming a magnetic isolation groove. The cross-sectional shape of the magnetic bridge 113 perpendicular to the axial direction is "S" shaped.

[0027] The present invention discloses a rotor core for a brushless motor, which is based on connecting the rotor core segments 112 and the core support 111 with a magnetic bridge, and forming a space between adjacent rotor core segments 112 to accommodate magnets, thereby forming a magnetic isolation groove between the magnets and the core support 111 to reduce magnetic leakage. Furthermore, the cross-sectional shape of the magnetic bridge 113 is defined as S-shaped, which not only further weakens magnetic leakage compared to a straight magnetic bridge structure, but also requires a smaller width to achieve the same structural strength, thus having a stronger ability to limit magnetic leakage. In addition, the S-shape has deformability, which can absorb displacement and deformation, reduce peak stress, make the stress distribution more uniform, and reduce stress concentration. Moreover, adjacent rotor core segments 112 are not connected, thereby reducing the magnetic flux passing through and reducing magnetic leakage.

[0028] In some preferred embodiments, the iron core support 111 is a cylindrical structure.

[0029] In some preferred embodiments, such as Figure 2 As shown, the cross-sectional width of the magnetic bridge 113 is W, 1mm≤W≤1.4mm; if the cross-sectional width of the magnetic bridge 113 is too large, it will not be able to limit the leakage flux, which will lead to a decrease in motor performance; if the width is too small, it will affect the mechanical strength; and / or, the length of the S-shaped cross-section of the magnetic bridge 113 is L (such as the length of the center line), L=(1.03-1.07)L1, where L1 is the radial distance between the end of the rotor core lobe 112 and the core support 111; if L is too large, the structural strength will be low; if L is too small, the overall structural strength will be reduced, and the effect of dispersing stress concentration will also be reduced.

[0030] Preferably, W is 1.2 mm; and / or, L = 1.05L1.

[0031] Preferably, the S-shape is a symmetrical shape, that is, the upper and lower parts are rotationally symmetrical.

[0032] In some preferred embodiments, such as Figure 1 , Figure 3 and Figure 4 As shown, the rotor core lobe 112 includes a core body 1121; the two sides of the outer end of the core body 1121 protrude outward to form a first limiting strip 1122 and a second limiting strip 1123, and the two sides of the inner end of the core body 1121 protrude outward to form a third limiting strip 1124 and a fourth limiting strip 1125; adjacent core bodies 1121 and the first limiting strip 1122, the second limiting strip 1123, the third limiting strip 1124 and the fourth limiting strip 1125 between adjacent core bodies 1121 form a space for accommodating magnets, and the magnets can be inserted into the space axially. A first through groove 1126 is recessed at the corner where the first limiting strip 1122 connects to the iron core body 1121; the bottom of the first through groove 1126 extends toward the outer surface of the iron core body 1121, and the minimum distance between the first through groove 1126 and the outer surface of the iron core body 1121 is H1, 0.5mm≤H1≤0.7mm; and / or, a second through groove 1127 is recessed at the corner where the second limiting strip 1123 connects to the iron core body 1121; the bottom of the second through groove 1127 extends toward the outer surface of the iron core body 1121, and the minimum distance between the second through groove 1127 and the outer surface of the iron core body 1121 is H2, 0.5mm≤H2≤0.7mm. By setting the first through slot 1126 and the second through slot 1127, and limiting the minimum distance between each of them and the outer surface of the iron core body 1121, the minimum width of the magnetic field flowing to the first limiting strip 1122 and the second limiting strip 1123 is reduced. Within the above-mentioned requirements, sufficient mechanical strength can be guaranteed and leakage magnetic field can be limited to the greatest extent. Furthermore, by setting the first through slot 1126 and the second through slot 1127, stress concentration at the connection can be reduced.

[0033] Preferably, H1 and H2 are equal, both being 0.6 mm.

[0034] Preferably, the cross-sectional shape of the iron core body 1121 is approximately fan-shaped.

[0035] Preferably, the first through groove 1126 and the second through groove 1127 have the same structure and both have irregular arc-shaped cross sections, thereby achieving a smooth transition of guiding stress and transferring high stress from the critical area.

[0036] In some preferred embodiments, such as Figure 3 and Figure 4As shown, the cross-sectional shape of the first through groove 1126 includes a first arc segment 11261 and a second arc segment 11262; one end of the first arc segment 11261 is connected to one end of the second arc segment 11262, and the other end intersects with the first limiting strip 1122; the other end of the second arc segment 11262 intersects with the iron core body 1121, and the curvature of the second arc segment 11262 is smaller than that of the first arc segment 11261; and / or, the cross-sectional shape of the second through groove 1127 includes a third arc segment 11271 and a fourth arc segment 11272; one end of the third arc segment 11271 is connected to one end of the fourth arc segment 11272, and the other end intersects with the second limiting strip 1123; the other end of the fourth arc segment 11272 intersects with the iron core body 1121, and the curvature of the fourth arc segment 11272 is smaller than that of the third arc segment 11271. Based on this, it can not only disperse stress, but also reduce the obstruction to the main magnetic flux flow and reduce leakage flux.

[0037] Preferably, the connection end of the first arc segment 11261 and the second arc segment 11262 is rounded; and / or, the connection end of the third arc segment 11271 and the fourth arc segment 11272 is rounded.

[0038] Preferably, the angle between the tangent at the midpoint of the first arc segment 11261 and the first side 11221 of the first limiting strip 1122 is β1, 140°≤β1≤150°; and / or, the angle between the tangent at the midpoint of the third arc segment 11271 and the second side 11231 of the second limiting strip 1123 is β2, 140°≤β2≤150°. Based on the obtuse angle setting, stress can be dispersed, improving the problem of magnetic concentration at the inflection point. More preferably, the first side 11221 and the second side 11231 are respectively in contact with the magnet; if the angle is too large, the leakage magnetic capacity decreases; if the angle is too small, the structural strength decreases.

[0039] Preferably, the outer edges of the cross sections of the first limiting strip 1122 and the second limiting strip 1123 are collinear with the outer edge of the cross section of the core body 1121.

[0040] Preferably, the included angles β1 and β2 are equal, both being 145°.

[0041] In some preferred embodiments, such as Figure 1 As shown, one or both sides of the rotor core lobe 112 have through grooves 1128, which are arranged axially and pass through both ends of the rotor core lobe 112. Based on the arrangement of the through grooves 1128, after or before the magnet is installed, glue is injected into the through grooves 1128 to fix the magnet in position. This can avoid the problem of glue overflow caused by applying glue to the side of the rotor core lobe 112 and can improve the adhesion.

[0042] Example 2 This embodiment provides a rotor for a brushless motor, such as... Figure 5As shown, the rotor 1 includes the rotor core 11, a plurality of magnets 12 and a rotating shaft 13 as described in Embodiment 1 above; the magnets 12 are disposed in the space formed between adjacent rotor core segments 112 for accommodating the magnets; the rotating shaft 13 is mounted on the rotor core 11, specifically as the core support 111 of the rotor core 11.

[0043] The present invention discloses a rotor for a brushless motor. The rotor core adopts a tangential rotor structure. The magnetic flux under one pole pitch is provided by two magnets connected in parallel. The magnetic concentration effect is used to improve the air gap magnetic density and the magnetic flux per pole, ensuring that the motor performance remains unchanged and the cost is significantly reduced. For mass production, the magnets can be quickly assembled using an automatic magnet insertion machine, thereby improving production efficiency.

[0044] In some preferred embodiments, the magnet 12 is made of ferrite. Based on this, an internal tangential rotor structure is adopted, and with the use of lower-cost ferrite, the air gap magnetic flux density and magnetic flux per pole are improved by utilizing the magnetic focusing effect, thereby improving motor performance and significantly reducing costs. Moreover, ferrite has weaker attraction than neodymium iron boron, and no special positioning fixtures and protective measures are required during assembly, which helps to improve assembly speed.

[0045] Example 3 This embodiment provides a brushless motor, such as Figure 6 and Figure 7 As shown, it includes the rotor core 11 in Embodiment 1 or the rotor 1 in Embodiment 2.

[0046] In some preferred embodiments, the system also includes a stator 2, a housing 3, and a stator coil 4; the stator coil 4 is made of enameled aluminum wire. Using aluminum wire instead of commonly used copper wire results in lower costs.

[0047] Preferably, the size of the tooth portion 21 and the yoke portion 22 can be reduced to increase the slot area, thereby increasing the number of stator coil 4 windings. Combined with ferrite magnets 12, compared to the magnetic field generated by neodymium iron boron magnets, ferrite magnets have lower air gap magnetic flux density due to their magnetic properties, and will not cause local magnetic flux saturation affecting motor performance, thus solving the problems of slot fill factor and magnetic flux saturation. The diameter of the aluminum wire can be increased to ensure motor performance. This ensures uniform magnetic flux distribution in the motor without affecting the stator winding.

[0048] In some preferred embodiments, such as Figure 8 As shown, the cross-section of stator 2 perpendicular to the axis is a rectangle with an arc-shaped chamfer. The yoke at the chamfer is thicker, which ensures the structural strength after thermal assembly with the outer shell 3. Compared with solid circular laminations, this design produces less waste, has a higher utilization rate, and can significantly reduce the amount of silicon steel sheets used, thereby reducing costs.

[0049] In some preferred embodiments, the outer casing 3 includes a front cover 31, a rear cover 32, and a stator housing 33; the front cover 31 and the rear cover 32 have the same structure and are respectively disposed on both sides of the stator housing 33, and are connected by bolts and anti-loosening nuts, so that the whole machine can be assembled in one go, greatly improving production efficiency; the fact that the front cover 31 and the rear cover 32 have the same structure can reduce mold costs and subsequent maintenance costs.

[0050] Preferably, the front cover 31 and the rear cover 32 are respectively provided with ribs along the axial direction. Based on the setting of the ribs, the strength is improved while the heat of the motor can be quickly dissipated.

[0051] In some preferred embodiments, the stator housing 33 is processed by a stretching aluminum process, and the motor stator core is fixed by a heat fitting. The mold cost is low, the assembly process is simple and mature, the heat dissipation performance is good, and it is suitable for mass production.

[0052] In some preferred embodiments, a speed reducer 5 and a fan blade 6 are also included; the speed reducer 5 is disposed on one side of the housing 3 and is drivenly connected to the rotor 1; the fan blade 6 is disposed on the other side of the housing 3 and is drivenly connected to the rotor 1. The fan blade 6 is designed to dissipate heat under heavy impact loads and prolonged overloads; and the speed reducer 5 is designed to be suitable for applications with high starting torque, such as those found in floor grinders.

[0053] Preferably, the fan blade 6 is mounted on the rotor 1 and abuts against the rotating shaft 13 of the rotor 1 via the bushing 7. Specifically, the bushing 7 can be a constricted structure, fitted onto the sleeve of the fan blade 6, which is fitted onto the rotating shaft 13. The constricted structure of the bushing 7 abuts against the rotating shaft 13, meaning the size of the constricted structure is smaller than the size of the sleeve. The sleeve is a deformable structure, such as an elastic material or a structure with an axial notch, so that the sleeve can deform and reduce its diameter to abut against the rotating shaft 13.

[0054] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A rotor core for a brushless motor, characterized in that, The rotor core includes a core support, multiple rotor core segments, and multiple magnetic bridges; Multiple rotor core segments are spaced apart circumferentially along the core support, and each rotor core segment is connected to the core support via a magnetic bridge. A space for accommodating magnets is formed between adjacent rotor core segments, and there is a gap between the space and the core support. The magnetic bridge has an "S" shaped cross-section perpendicular to the axial direction.

2. The rotor core for a brushless motor according to claim 1, characterized in that, The cross-sectional width of the magnetic bridge is W, 1mm≤W≤1.4mm; and / or, the length of the S-shaped cross-section of the magnetic bridge is L, L=(1.03-1.07)L1, where L1 is the radial distance between the end of the rotor core lobe and the core support.

3. The rotor core for a brushless motor according to claim 2, characterized in that, The W is 1.2 mm; and / or the L is 1.05L1.

4. The rotor core for a brushless motor according to claim 1, characterized in that, The rotor core segments include the core body; The outer ends of the iron core body protrude outwards on both sides to form a first limiting strip and a second limiting strip, and the inner ends of the iron core body protrude outwards on both sides to form a third limiting strip and a fourth limiting strip. A first through groove is formed at the corner where the first limiting strip connects to the iron core body; the minimum distance between the first through groove and the outer surface of the iron core body is H1, 0.5mm≤H1≤0.7mm; And / or, A second through groove is formed at the corner where the second limiting strip connects to the iron core body; the minimum distance between the second through groove and the outer surface of the iron core body is H2, 0.5mm≤H2≤0.7mm.

5. The rotor core for a brushless motor according to claim 4, characterized in that, H1 and H2 are equal, both being 0.6 mm.

6. The rotor core for a brushless motor according to claim 4, characterized in that, The cross-sectional shape of the first through slot includes a first arc segment and a second arc segment; one end of the first arc segment is connected to one end of the second arc segment, and the other end intersects with the first limiting strip; the other end of the second arc segment intersects with the iron core body, and the curvature of the second arc segment is smaller than that of the first arc segment; And / or, The cross-sectional shape of the second through groove includes a third arc segment and a fourth arc segment; One end of the third arc segment is connected to one end of the fourth arc segment, and the other end intersects with the second limiting strip; the other end of the fourth arc segment intersects with the iron core body, and the curvature of the fourth arc segment is smaller than that of the third arc segment.

7. The rotor core for a brushless motor according to claim 6, characterized in that, The angle between the tangent at the midpoint of the first arc segment and the first side of the first limiting strip is β1, where 140°≤β1≤150°; And / or, The angle between the tangent at the midpoint of the third arc segment and the second side of the second limiting strip is β2, where 140°≤β2≤150°.

8. The rotor core for a brushless motor according to claim 7, characterized in that, The included angles β1 and β2 are equal, both being 145°.

9. The rotor core for a brushless motor according to any one of claims 1-8, characterized in that, The rotor core has through slots on one or both sides.

10. A rotor for a brushless motor, characterized in that, The rotor includes a rotor core as described in any one of claims 1-9, a plurality of magnets, and a rotating shaft; The magnet is disposed within the space formed between adjacent rotor core segments for accommodating the magnet. The rotating shaft is mounted on the rotor core.

11. The rotor for a brushless motor according to claim 10, characterized in that, The magnet is made of ferrite.

12. A brushless motor, characterized in that, It includes the rotor core as described in any one of claims 1-9 or the rotor as described in claim 10 or 11.

13. The brushless motor according to claim 12, characterized in that, It also includes a stator, a housing, and a stator coil; the stator coil is made of enameled aluminum wire.

14. The brushless motor according to claim 13, characterized in that, The cross-section of the stator perpendicular to the axis is a rectangle with an arc-shaped chamfer.

15. The brushless motor according to claim 13, characterized in that, It also includes a speed reducer and fan blades; The speed reducer is disposed on one side of the housing and is connected to the rotor drive; The fan blades are located on the other side of the housing and are connected to the rotor drive.

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