Motor rotor, motor, and motor rotor assembly method

Abstract

The present invention relates to the technical field of electric power equipment, and in particular to a motor rotor, a motor and a motor rotor assembly method, so as to improve the operating reliability of the motor and the torque that a rotating shaft can bear. The motor rotor comprises a rotating shaft and a rotor core sleeved on the rotating shaft, and the rotor core is fixed with a plurality of permanent magnets distributed along the circumferential direction, and is characterized in that the rotor core comprises a mounting hole sleeved on the rotating shaft, the inner wall of the mounting hole has a groove extending in the axial direction, the diameter of the rotating shaft is larger than the aperture of the mounting hole, and the depth of the groove is larger than the difference between the diameter of the rotating shaft and the aperture of the mounting hole.

Description

Technical Field

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

[0002] Since the power range that electric motors can provide is very large, with the development of economy and the improvement of productivity, they have been applied in all aspects of modern social life. Electric motors are a kind of equipment that converts electrical energy into mechanical energy. It uses the stator winding to generate a rotating magnetic field and acts on the rotor to form a magnetic electrodynamic rotating torque.

[0003] Usually, the stator winding is an energized coil, and the rotor includes a rotating shaft and a rotor core sleeved on the rotating shaft, and a plurality of permanent magnets are fixed on the rotor core. When the motor is working, the stator applies an electromagnetic field to the outside of the rotor, and the electromagnetic field drives the rotor core to rotate through the repulsive or attractive effect between the electromagnetic field and the magnetic field generated by the permanent magnets fixed on the rotor core, thereby driving the rotating shaft to rotate, converting electrical energy into kinetic energy, and then outputting the kinetic energy to the external machine through the rotating shaft. Therefore, it is necessary to mechanically fix the rotor core to the rotating shaft, and in order to improve the reliability of the mechanical fixation between the rotating shaft and the rotor core and increase the torque that the rotating shaft can withstand, it is necessary to increase the fixing strength between the rotating shaft and the rotor core. Summary of the invention

[0004] The invention provides a motor rotor, a motor and a method for assembling the motor rotor, wherein the fixing strength between the rotating shaft and the rotor core is improved, thereby improving the running reliability of the motor and the torque that the rotating shaft can bear.

[0005] To this end, an embodiment of the present invention provides an electric motor rotor, which includes: a rotating shaft and a rotor core sleeved on the rotating shaft, the rotor core being fixed with a plurality of permanent magnets distributed along the circumferential direction, the rotor core including a mounting hole sleeved on the rotating shaft, the inner wall of the mounting hole having a groove extending axially, and before the sleeve is mounted, the diameter of the rotating shaft is larger than the aperture of the mounting hole, and the depth of the groove is larger than the difference between the diameter of the rotating shaft and the aperture of the mounting hole.

[0006] In this technical solution, the rotating shaft and the rotor core can be interference fitted; as the interference fit between the rotating shaft and the mounting hole increases, the groove on the inner wall of the mounting hole can also increase the friction between the mounting hole and the rotating shaft, and increase the tangential force between the mounting hole and the rotating shaft, thereby further improving the fixing strength between the rotating shaft and the rotor core, and increasing the torque that can be transmitted between the mounting hole and the rotating shaft.

[0007] In a preferred technical solution, after the rotating shaft and the rotor core are sleeved, a convex ridge structure protruding into the groove is formed in a region of the rotating shaft opposite to the groove.

[0008] In this embodiment, not only the interference fit between the rotating shaft and the mounting hole is increased, but the convex rib structure on the rotating shaft and the groove can be clamped in the circumferential direction, the ability to transmit tangential force is further enhanced, and the fixing strength between the rotating shaft and the rotor core is further improved, thereby increasing the torque that the rotating shaft of the motor can withstand.

[0009] Specifically, the hot pressing fixing fitting stress between the rotating shaft and the rotor core is less than the yield strength of the rotating shaft material, and less than the yield strength of the rotor core material. The hot pressing fixing fitting stress will not cause damage to the materials of the rotating shaft and the rotor core, thereby ensuring the fixing strength between the rotating shaft and the rotor core and effectively transmitting torque.

[0010] In one of the technical solutions, the groove includes a plurality of grooves distributed circumferentially along the inner wall of the mounting hole, thereby further improving the fixing strength between the rotating shaft and the rotor core.

[0011] In one of the technical solutions, the permanent magnets are arranged in such a way that the magnetic poles of adjacent permanent magnets are in opposite directions, and the number and position of the plurality of grooves are arranged to be opposite to a group of permanent magnets with the same magnetic pole direction. The grooves can serve as markers to distinguish two groups of permanent magnets with opposite magnetic pole directions. When installing or replacing permanent magnets, operators can directly determine the magnetic pole direction of the permanent magnets based on the positions of the grooves without the need for additional detection work, thereby improving work efficiency.

[0012] In a preferred technical solution, along the circumferential direction, the center of the groove and the center of the permanent magnet opposite to the groove deviate by a set angle; the motor rotor includes at least two rotor cores, and when observed from the axial end of the rotating shaft, the assembly directions of two adjacent rotor cores are opposite and the grooves are connected.

[0013] In this solution, the permanent magnets of the two rotor cores are staggered, so that the interval area between two adjacent permanent magnets can complement each other, so that the magnetic field of the rotor core tends to be uniform in the circumferential direction, thereby improving the uniformity of the rotation of the motor rotor.

[0014] In one of the technical solutions, the rotor core also includes a leakage-proof magnetic hole formed corresponding to each permanent magnet. When observed from the shaft end of the rotating shaft, the cross-sectional shape of the leakage-proof magnetic hole is an isosceles triangle, and the vertex angle of the isosceles triangle points to the center position of the permanent magnet. The cross-sectional shape of the permanent magnet is a rectangle, and the groove is formed in: the extension lines of the sides at both ends of the rectangle, the extension lines of the two isosceles sides of the isosceles triangle, and the area surrounded by the edge line of the mounting hole. The magnetic field in this area is relatively weak, and it can be considered as the weak magnetic area of ​​the rotor core. If the groove is set in the weak magnetic area of ​​the rotor core, it will have little effect on the magnetic field of the rotor core, so that the rotor has good performance.

[0015] Based on the same inventive concept, the present invention also provides another electric motor rotor, which includes a rotating shaft and a rotor core sleeved on the rotating shaft, the rotor core is fixed with a plurality of permanent magnets distributed along the circumferential direction, the rotor core includes a mounting hole sleeved on the rotating shaft, the inner wall of the mounting hole has a groove extending along the axial direction, the rotating shaft and the rotor core are assembled by a hot pressing process or a physical pressing process, and a convex ridge structure protruding into the groove is formed in the area where the rotating shaft is opposite to the groove.

[0016] In this technical solution, not only the interference fit between the rotating shaft and the mounting hole is increased, but the convex rib structure on the rotating shaft and the groove can be clamped in the circumferential direction, the ability to transmit tangential force is further enhanced, and the fixing strength between the rotating shaft and the rotor core is further improved, thereby increasing the torque that the rotating shaft of the motor can withstand.

[0017] Specifically, the hot pressing fixing fitting stress between the rotating shaft and the rotor core is less than the yield strength of the rotating shaft material, and less than the yield strength of the rotor core material. The hot pressing fixing fitting stress will not cause damage to the materials of the rotating shaft and the rotor core, thereby ensuring the fixing strength between the rotating shaft and the rotor core and effectively transmitting torque.

[0018] In one of the technical solutions, the groove includes a plurality of grooves distributed circumferentially along the inner wall of the mounting hole, thereby further improving the fixing strength between the rotating shaft and the rotor core.

[0019] In one of the technical solutions, the permanent magnets are arranged in such a way that the magnetic poles of adjacent permanent magnets are in opposite directions, and the number and position of the plurality of grooves are arranged to be opposite to a group of permanent magnets with the same magnetic pole direction. The grooves can serve as markers to distinguish two groups of permanent magnets with opposite magnetic pole directions. When installing or replacing permanent magnets, operators can directly determine the magnetic pole direction of the permanent magnets based on the positions of the grooves without the need for additional detection work, thereby improving work efficiency.

[0020] In a preferred technical solution, along the circumferential direction, the center of the groove and the center of the permanent magnet opposite to the groove deviate by a set angle; the motor rotor includes at least two rotor cores, and when observed from the axial end of the rotating shaft, the assembly directions of two adjacent rotor cores are opposite and the grooves are connected.

[0021] In this solution, the permanent magnets of the two rotor cores are staggered, so that the spacing area between two adjacent permanent magnets can complement each other, making the magnetic field of the rotor core tend to be uniform in the circumferential direction, improving the uniformity of the rotation of the motor rotor, and thus improving the uniformity of the rotation speed of the motor rotor.

[0022] In one of the technical solutions, the rotor core also includes a leakage-proof magnetic hole formed corresponding to each permanent magnet. When observed from the shaft end of the rotating shaft, the cross-sectional shape of the leakage-proof magnetic hole is an isosceles triangle, and the vertex angle of the isosceles triangle points to the center position of the permanent magnet. The cross-sectional shape of the permanent magnet is a rectangle, and the groove is formed in: the extension lines of the sides at both ends of the rectangle, the extension lines of the two isosceles sides of the isosceles triangle, and the area surrounded by the edge line of the mounting hole. The magnetic field in this area is relatively weak, and it can be considered as the weak magnetic area of ​​the rotor core. If the groove is set in the weak magnetic area of ​​the rotor core, it will have little effect on the magnetic field of the rotor core, so that the rotor has good performance.

[0023] The present invention also provides an electric motor, which comprises the electric motor rotor in any one of the above technical solutions. The electric motor has high operating reliability and outputs greater torque.

[0024] Based on the same inventive concept, the present invention also provides a method for assembling a motor rotor, which is applied to the motor rotor in the above technical solution and specifically comprises the following steps:

[0025] A heating step of heating the rotor core, wherein the heating temperature and duration are such that the diameter of the mounting hole of the rotor core for sleeve mounting the rotating shaft is larger than the diameter of the rotating shaft;

[0026] A step of sleeve-mounting the heated rotor core on the rotating shaft to form the motor rotor;

[0027] In the cooling step of cooling the motor rotor, a convex ridge structure is formed in the area of ​​the rotating shaft opposite to the groove located on the inner wall of the mounting hole and extending in the axial direction, and the convex ridge structure protrudes into the groove.

[0028] In this technical solution, the rotor core and the rotating shaft are installed by hot pressing process, so that the interference fit between the two is achieved, and the area where the rotating shaft and the groove are opposite to each other forms a convex ridge structure. The convex ridge structure on the rotating shaft can be engaged with the groove in the circumferential direction, and the ability to transmit tangential force is further enhanced, which further improves the fixing strength between the rotating shaft and the rotor core, and can increase the torque that the rotating shaft of the motor can withstand.

[0029] In a specific technical solution, the heating step specifically includes: heating at least two rotor cores, the rotor cores being fixed with a plurality of permanent magnets distributed along the circumferential direction, and along the circumferential direction of the rotor cores, the center of the groove and the center of the permanent magnet opposite to the groove deviate by a set angle;

[0030] The sleeve step specifically includes: sleeve the heated rotor cores on the rotating shaft respectively, wherein two adjacent rotor cores are installed in opposite directions, and the grooves of the at least two rotor cores are connected.

[0031] In this technical solution, after installation, the motor rotor is formed, and the permanent magnets of the two rotor cores are staggered, so that the spacing area between two adjacent permanent magnets can complement each other, so that the magnetic field of the rotor core tends to be uniform in the circumferential direction, thereby improving the uniformity of the rotation of the motor rotor and thus improving the uniformity of the rotation speed of the motor rotor.

[0032] Based on the same inventive concept, the present invention also provides a method for assembling a motor rotor, which is applied to the motor rotor in the above technical solution and specifically comprises the following steps:

[0033] The step of pressing the rotating shaft into the rotor core comprises: before pressing, the diameter of the rotating shaft is larger than the aperture of the mounting hole, the depth of the groove is larger than the difference between the diameter of the rotating shaft and the aperture of the mounting hole, and after pressing, the rotating shaft and the groove located on the inner wall of the mounting hole and extending axially form a convex ridge structure protruding into the groove.

[0034] In this technical solution, the area where the rotating shaft and the groove are opposite to each other can also form a convex ridge structure. The convex ridge structure on the rotating shaft can be clamped with the groove in the circumferential direction, and the ability to transmit tangential force is further enhanced, and the fixing strength between the rotating shaft and the rotor core is further improved, which can increase the torque that the rotating shaft of the motor can withstand. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic structural diagram showing a first embodiment of a motor rotor of the present invention;

[0036] Figure 2 A schematic cross-sectional view of a first embodiment of a motor rotor of the present invention is shown;

[0037] Figure 3 A schematic cross-sectional view of a second embodiment of a motor rotor of the present invention is shown;

[0038] Figure 4 Shows Figure 3 A partial enlarged view of the middle part;

[0039] Figure 5 A schematic cross-sectional view of a third embodiment of a motor rotor of the present invention is shown;

[0040] Figure 6 A schematic cross-sectional structure diagram of a fifth embodiment of the motor rotor of the present invention is shown, with the observation direction being the first end face;

[0041] Figure 7 A schematic cross-sectional view of a fifth embodiment of the motor rotor of the present invention is shown, with the second end face being viewed in the direction of observation;

[0042] Figure 8 A schematic assembly diagram of a fifth embodiment of the motor rotor of the present invention is shown;

[0043] Fig. 9 A partial schematic diagram showing a seventh embodiment of the rotor core of the present invention;

[0044] Fig.10 A partial schematic diagram of an eighth embodiment of the rotor core of the present invention is shown.

[0045] Reference numerals:

[0046] 1-rotating shaft; 11-axis line;

[0047] 12-convex corrugated structure; 2-rotor core;

[0048] 21-permanent magnet; 211-first permanent magnet;

[0049] 212 - a second permanent magnet; 213 - two end side edges of the permanent magnet;

[0050] 22-mounting hole; 221-groove;

[0051] 23- spacing area; 24- leakage-proof magnetic hole;

[0052] 241- two end side edges of the anti-leakage magnetic hole; 25- weak magnetic area. DETAILED DESCRIPTION

[0053] When the motor is working, the rotor rotates under the action of the stator and outputs torque to the external machine. In order to increase the torque that the motor shaft can withstand and maintain the reliability of the motor operation, it is necessary to increase the fixing strength between the rotor shaft and the rotor core. In the present invention, a groove is provided in the mounting hole of the rotor core, and the diameter of the shaft is larger than the diameter of the mounting hole, so that the shaft and the rotor core can be fitted with interference fit; the groove structure can increase the friction between the mounting hole and the shaft, and increase the tangential force between the mounting hole and the shaft, thereby further improving the fixing strength between the shaft and the rotor core, and increasing the torque that can be transmitted between the mounting hole and the shaft.

[0054] Furthermore, in the present invention, the rotating shaft and the rotor core of the motor rotor can be assembled by hot pressing. After the installation is completed, a convex ridge structure protruding into the groove is formed on the rotating shaft. The convex ridge structure on the rotating shaft and the groove can be clamped in the circumferential direction, and the ability to transmit tangential force is further enhanced, and the fixing strength between the rotating shaft and the rotor core is further improved, and the torque that the rotating shaft of the motor can withstand is increased.

[0055] To more clearly understand the embodiments of the present invention, specific embodiments are described in detail with reference to the accompanying drawings, in which similar components or the same components are represented by the same reference numerals.

[0056] Reference Figure 1 , which is a motor rotor in a first embodiment of the present invention, comprising a rotating shaft 1 and a rotor core 2 sleeved on the rotating shaft 1;

[0057] Please refer to Figure 2 The rotor core 2 includes a plurality of permanent magnets 21 distributed along the circumferential direction and a mounting hole 22 for mounting the rotor core 2 to the rotating shaft 1 , and the inner wall of the mounting hole 22 has a groove 221 extending along the axial direction. Figure 2 The dotted line in the figure shows the processing size of the shaft 1. Specifically, before sleeve installation, the diameter of the shaft 1 is larger than the aperture of the mounting hole 22, and the depth of the groove 221 is larger than the difference between the diameter of the shaft 1 and the aperture of the mounting hole 22. All the sizes refer to the processing size, that is, the processing diameter of the shaft 1 is larger than the processing aperture of the mounting hole 22, and the distance between the bottom wall of the groove 221 and the axis of the shaft 1 is larger than the diameter of the shaft 1.

[0058] The following is a detailed description of the assembly process of the motor rotor in this embodiment:

[0059] First, before installation, the diameter of the rotating shaft 1 is larger than the aperture of the mounting hole 22, so that an interference fit can be achieved between the rotating shaft 1 and the mounting hole 22 of the rotor core 2. During installation, the rotating shaft 1 can be cooled and shrunk first to reduce the diameter of the rotating shaft 1, and then the mounting hole 22 of the rotor core 2 is sleeved on the outside of the rotating shaft 1. Preferably, at this time, the rotating shaft 1 and the mounting hole 22 are interference fit, and when the temperature of the rotating shaft 1 returns to room temperature, the interference amount between the rotating shaft 1 and the mounting hole 22 can be increased, so that the fixing strength between the rotating shaft 1 and the rotor core 2 is higher. In addition, during installation, the rotor core 2 can also be heated to expand it, so that the aperture of the mounting hole 22 is increased, and then the mounting hole 22 of the rotor core 2 is sleeved on the outside of the rotating shaft 1. Preferably, at this time, the rotating shaft 1 and the mounting hole 22 are interference fit, and when the temperature of the rotor core 2 returns to room temperature, the interference amount between the rotating shaft 1 and the mounting hole 22 can also be increased, so that the fixing strength between the rotating shaft 1 and the rotor core 2 is higher.

[0060] In this embodiment, as the interference fit between the rotating shaft 1 and the mounting hole 22 increases, the groove 221 on the inner wall of the mounting hole 22 can also increase the friction between the mounting hole 22 and the rotating shaft 1, and increase the tangential force between the mounting hole 22 and the rotating shaft 1, thereby further increasing the fixing strength between the rotating shaft 1 and the rotor core 2, and increasing the torque that can be transmitted between the mounting hole 22 and the rotating shaft 1.

[0061] Specifically, the depth of the groove is greater than the difference between the diameter of the shaft and the aperture of the mounting hole. In this embodiment, the shape of the inner bottom surface of the groove can be a plane or a curved surface, and is not specifically limited. Here, the depth of the groove refers to the depth at the lowest point inside the groove. The depth of the groove needs to be able to accommodate the convex structure formed by the shaft.

[0062] Please refer to Figure 3 and Figure 4 In order to further improve the fixing strength between the rotating shaft 1 and the rotor core 2 and increase the torque that the rotating shaft of the motor can withstand, a second embodiment of the present invention is also provided, which is basically similar to the motor rotor provided in the first embodiment, and the only difference is that in this embodiment, it is specifically pointed out that after the rotating shaft and the rotor core are installed, a convex rib structure 12 protruding into the groove 221 is formed on the rotating shaft 1.

[0063] In this embodiment, the machining diameter of the shaft 1 and the machining aperture of the mounting hole 22 should have a large difference. When installing the rotor, the shaft 1 and the rotor core 2 can be assembled by a hot pressing process, that is, the rotor core 2 is first heated and expanded to increase the aperture of the mounting hole 22, and then the mounting hole 22 of the rotor core 2 is sleeved on the outer side of the shaft 1; preferably, at this time, the shaft 1 and the mounting hole 22 are interference fit, and when the temperature of the shaft 1 returns to room temperature, since the aperture of the mounting hole 22 is much different from the diameter of the shaft 1, as the temperature of the rotor core 2 decreases, the mounting hole 22 gradually recovers its aperture, and the shaft 1 is subjected to the pressure of the mounting hole 22, so that the area of ​​the shaft 1 corresponding to the groove 221 of the mounting hole 22 is squeezed into the groove 221, thereby forming a convex corrugated structure 12 protruding into the groove 221. Alternatively, the shaft 1 and the rotor core 2 can also be assembled by a physical pressing process, that is, without heating treatment, physical pressing assembly is performed at room temperature to form a convex corrugated structure 12 protruding into the groove 221.

[0064] In this embodiment, not only the interference fit between the rotating shaft 1 and the mounting hole 22 is increased, but also the convex rib structure 12 on the rotating shaft 1 and the groove 221 can be clamped in the circumferential direction, thereby further enhancing the ability to transmit tangential force. The fixing strength between the rotating shaft 1 and the rotor core 2 is further improved, thereby increasing the torque that the rotating shaft of the motor can withstand.

[0065] Specifically, the depth of the groove is greater than the difference between the diameter of the rotating shaft and the aperture of the mounting hole. In this embodiment, the shape of the inner bottom surface of the groove can be a plane or a curved surface, and is not specifically limited. Here, the depth of the groove refers to the depth at the lowest point inside the groove. The depth of the above-mentioned groove can enable the groove to accommodate the convex corrugated structure formed on the rotating shaft.

[0066] In addition, in this embodiment, it is only necessary to form a groove 221 in the mounting hole 22 of the rotor core 2, and the shaft 1 can be a cylindrical shape with a smooth surface. There is no need to perform additional processing on the shaft 1, the manufacturing process is relatively simple, and efficiency can be improved.

[0067] Considering that the interference fit between the shaft 1 and the mounting hole 22 of the rotor core 2 is too large, which may cause material failure defects in the shaft 1 and / or the rotor core 2, the hot pressing fixing stress between the shaft 1 and the rotor core 2 is less than the yield strength of the shaft 1 material, and less than the yield strength of the rotor core 2 material.

[0068] It should be pointed out that the above yield strength refers to the yield strength required for material failure, rather than the deformation strength required for material deformation. The hot pressing fixing stress should be greater than the above deformation strength but less than the yield strength. In this embodiment, the hot pressing fixing stress will not cause damage to the materials of the rotating shaft 1 and the rotor core 2, thereby ensuring the fixing strength between the rotating shaft 1 and the rotor core 2 and effectively transmitting the torque.

[0069] Specifically, the above-mentioned hot pressing fixing stress is calculated according to the following relationship:

[0070]

[0071] Among them, ΔR is the hot pressing fixing amount between the shaft and the mounting hole, which is specifically based on the relationship ΔR=R s ·K s ·tR r ·K r t is determined, R s is the diameter of the shaft, R r is the diameter of the mounting hole, R2 is the distance between the bottom surface of the anti-leakage magnetic hole close to the shaft and the axis of the shaft, K s is the linear expansion coefficient of the shaft, K r is the linear expansion coefficient of the rotor core, t is the ambient temperature, ρ r is the Poisson's ratio of the rotor core, ρ s is the Poisson's ratio of the rotating shaft.

[0072] It should be noted that, in this embodiment, the strength of the shaft 1 should be smaller than the strength of the rotor core 2 so that when the temperature of the rotor core 2 returns to room temperature, the shape of the shaft 1 changes to form a convex rib structure 12 protruding into the groove 221 .

[0073] Please refer to Figure 5 In order to further improve the fixing strength between the rotating shaft 1 and the rotor core 2, based on the first embodiment, a third embodiment of the present invention is also provided. In this embodiment, the rotor core 2 has a plurality of grooves 221 distributed circumferentially along the inner wall of the mounting hole 22.

[0074] The motor rotor provided by this embodiment has multiple grooves 221 distributed on the inner wall of the mounting hole 22. When the rotating shaft 1 is assembled in the mounting hole 22, multiple groups of tangential forces can be provided in the circumferential direction of the rotating shaft 1, thereby further improving the fixing strength between the rotating shaft 1 and the rotor core 2.

[0075] Preferably, the plurality of grooves 221 are evenly distributed on the inner wall of the mounting hole 22 . Then, since the tangential force provided by the grooves 221 is more evenly distributed in the circumferential direction, the uniformity of the torque transmitted between the rotating shaft 1 and the rotor core 2 can also be improved.

[0076] Please continue to refer to Figure 5 Furthermore, in order to facilitate the installation of the permanent magnet 21, a fourth embodiment of the present invention is provided on the basis of the third embodiment. In this embodiment, according to the different magnetic pole directions of the permanent magnet 21 during installation, the permanent magnet 21 fixed on the rotor core 2 is divided into a first permanent magnet 211 and a second permanent magnet 212. The first permanent magnet 211 and the second permanent magnet 212 are arranged at intervals from each other, and the above-mentioned multiple grooves 221 are respectively opposite to the first permanent magnet 211 one by one, or, respectively opposite to the second permanent magnet 212 one by one.

[0077] It is worth mentioning that Figure 5 Only one specific embodiment is shown, in which the grooves 221 are opposite to the first permanent magnets 211 one by one, and the S poles of the first permanent magnets 211 face the mounting hole 22. Of course, in practical applications, the grooves 221 can also face the permanent magnets 21 with the N poles facing the rotating shaft 1.

[0078] In this embodiment, the groove 221 is only opposite to one of the first permanent magnet 211 or the second permanent magnet 212. Therefore, when the permanent magnet 21 is installed on the rotor core 2, the permanent magnet 21 can be directly installed according to the predetermined magnetic pole of the permanent magnet 21 opposite to the groove 221, or the first permanent magnet 211 and the second permanent magnet 212 of the permanent magnet 21 can be arranged at intervals from each other. For example, Figure 5 In a specific embodiment shown, the permanent magnet 21 with the S pole facing the mounting hole 22 is set to be opposite to the groove 221. Then, when the rotor core 2 is assembled, when the assembly area relative to the groove 221 is encountered, the S pole of the permanent magnet 21 is directed toward the mounting hole 22, and when the assembly area is not relative to the groove 221, the N pole of the permanent magnet 21 is directed toward the mounting hole 22. The installation process is simplified, the assembly efficiency is improved, and the problem of assembly errors caused by operator negligence can be reduced. In addition, when the permanent magnet 21 of the rotor core 2 is damaged and needs to be repaired and replaced, the maintenance personnel can directly determine the magnetic pole direction of the permanent magnet 21 according to the position of the groove 221 without performing additional detection work, thereby improving work efficiency.

[0079] Please refer to Figures 6 to 8 Based on the first embodiment, a fifth embodiment of the present invention is also provided. In this embodiment, the motor rotor includes two rotor cores 2. Along the circumferential direction, the center of the groove 221 of each rotor core 2 and the center of the permanent magnet 21 opposite to the groove 221 deviate by a set angle. When the motor rotor is observed from the axial end of the rotating shaft 1, the assembly directions of the two rotor cores 2 are opposite and the grooves 221 are opposite.

[0080] In this embodiment, the two rotor cores 2 are assembled in opposite directions. Figure 6 and Figure 7 As shown in FIG. 1 , two rotor cores 2 are in opposite directions. When the permanent magnets 21 of the two rotor cores 2 are facing each other, the grooves 221 of the two rotor cores 2 are staggered. The circumferential direction of the rotating rotor core 2 is as shown in FIG. Figure 8 As shown, by making the grooves 221 of the two rotor cores 2 face each other, the permanent magnets 21 of the two rotor cores 2 can be staggered. Since there is a spacing area 23 between two adjacent permanent magnets 21, the magnetic field at the spacing area 23 is weak, resulting in uneven magnetic field of the rotor core 2 in the circumferential direction, which can easily cause uneven rotation of the rotor when the motor is working. In the embodiment of the present invention, the permanent magnets 21 of the two rotor cores 2 are staggered, and the spacing area 23 can complement each other, so that the magnetic field of the rotor core 2 in the circumferential direction tends to be uniform, thereby improving the uniformity of the rotation of the motor rotor, thereby improving the uniformity of the rotation speed of the motor rotor.

[0081] In this embodiment, when installing the rotor core 2, by observing the position of the groove 221, the grooves 221 of the two rotor cores 2 are made to face each other, so that the permanent magnets 21 of the two rotor cores 2 can be staggered, which is convenient for the assembly operation of the motor rotor. Specifically, at least the permanent magnet 21 of one rotor core 2 should be able to cover the corresponding spacing area 23 of the other rotor core 2. According to the design requirements, along the circumferential direction, the deviation angle of the permanent magnets 21 of the two rotor cores 2 is α, then the setting angle of the deviation between the center of the groove 221 and the center of the permanent magnet 21 opposite to the groove 221 is

[0082] Specifically, the opposite assembly directions of the two rotor cores 2 can be understood as follows: the end faces of the rotor core 2 are respectively the first end face and the second end face. When assembling one rotor core 2, the shaft 1 extends into the mounting hole 22 of the rotor core 2 from the direction of the first end face. When assembling the other rotor core 2, the shaft 1 extends into the mounting hole 22 of the rotor core 2 from the direction of the second end face. In the assembled motor rotor, the second end face of one rotor core 2 is opposite to the second end face of the other rotor core 2, and the assembly directions of the two rotor cores 2 are opposite. Figure 6 A first end face of the rotor core 2 is shown; Figure 7 The second end face of the rotor core 2 is shown.

[0083] Please continue to refer to Fig. 9 Based on the first embodiment, a sixth embodiment of the present invention is also provided. In this embodiment, on the rotor core 2, a magnetic leakage prevention hole 24 is provided in the direction of each permanent magnet 21 toward the mounting hole 22, and a set distance is separated between the bottom wall of the groove 221 and the magnetic leakage prevention hole.

[0084] In this embodiment, the anti-leakage magnetic hole 24 is provided to reduce the diffusion of the magnetic field of the permanent magnet 21 toward the mounting hole 22, and to increase the density of the magnetic field in the working area of ​​the permanent magnet 21, thereby improving the working efficiency of the motor. Specifically, if the groove 221 is connected to the anti-leakage magnetic hole or the distance between the bottom wall of the groove 221 and the anti-leakage magnetic hole is too small, the strength of the rotor core 2 will be reduced, and it will be easy to deform and fail. Therefore, in this embodiment, the bottom wall of the groove 221 is separated from the anti-leakage magnetic hole by a set distance, which can improve the strength of the rotor core 2 and increase the service life of the motor rotor.

[0085] The rotor core has a weak magnetic area around the permanent magnet and the anti-leakage magnetic hole, and the magnetic lines of force in the weak magnetic area are less distributed and the magnetic flux density is smaller. The above groove is arranged in the weak magnetic area of ​​the rotor core 2, which has less effect on the magnetic field of the rotor core 2, so that the rotor has good performance.

[0086] In a specific embodiment, the cross-sectional shape of the permanent magnet and the shape of the anti-leakage magnetic hole are not fixed, but the weak magnetic area of ​​the rotor core can be determined roughly according to the following method: along the circumferential direction, the two end points of the two end side edges 213 of the permanent magnet are point A and point B respectively, and the two end points of the two end side edges 241 of the anti-leakage magnetic hole are point C and point D respectively, then, the area surrounded by the extension line of the line connecting point C and point D of the two end side edges 241 of the anti-leakage magnetic hole opposite to the groove 221, the extension line of the line connecting point A and point B of the two end side edges 213 of the permanent magnet adjacent to the groove 221, and the edge line of the mounting hole 22 is called the weak magnetic area 25, in which the magnetic field generated by the permanent magnet 21 is relatively weak, and the groove 221 is arranged in the above-mentioned weak magnetic area 25. In this embodiment, the groove 221 is located in the weak magnetic area 25 of the permanent magnet 21, which has little effect on the magnetic field of the rotor core 2, so that the rotor has good performance.

[0087] Please refer to Fig.10On the basis of the sixth embodiment, a seventh embodiment of the present invention is also provided. In this embodiment, observed from the axial end of the rotating shaft 1, the cross-sectional shape of the permanent magnet 21 is a rectangle, and the cross-sectional shape of the anti-leakage magnetic hole 24 is approximately an isosceles triangle, then the two end side edges 241 of the anti-leakage magnetic hole and the two end side edges 213 of the permanent magnet are both straight lines, and the extension lines of the two end side edges 213 of the permanent magnet, the extension lines of the two end side edges 241 of the anti-leakage magnetic hole and the edge lines of the mounting hole 22 form a weak magnetic zone 25, which is the weak magnetic zone 25, and the groove 221 is located in the weak magnetic zone 25.

[0088] Specifically, there is no limitation on the way of installing the permanent magnet on the rotor core. For example, the permanent magnet can be bonded to the circumferential side of the rotor core, or the permanent magnet can be embedded in the rotor core from the end surface of the rotor core.

[0089] The present invention also provides an electric motor, which comprises the electric motor rotor in any one of the above schemes. The operation reliability of the electric motor is high, and the torque that the rotating shaft of the electric motor can withstand is greater.

[0090] Specifically, the motor may be a surface permanent magnet (SPM) motor or an interior permanent magnet (IPM) motor.

[0091] Based on the same inventive concept, the present invention also provides an assembly method for the motor rotor in the above-mentioned scheme. Specifically, in one embodiment, the motor rotor includes a rotating shaft and a rotor core, the rotor core has a mounting hole, and the inner wall of the mounting hole has a groove, wherein the machining diameter of the rotating shaft is greater than the machining diameter of the mounting hole, and the machining depth of the groove is greater than the difference between the machining diameter of the rotating shaft and the machining hole diameter of the mounting hole. In this embodiment, the rotating shaft and the rotor core are assembled by a hot pressing process, and the assembly method includes:

[0092] The first step is a heating step, in which the rotor core is heated, and the heating temperature and duration are controlled so that the aperture of the mounting hole on the rotor core for sleeved shaft is larger than the machining diameter of the shaft; the second step is a sleeve step, in which the heated rotor core is sleeved on the outside of the shaft; the third step is a cooling step, in which the rotor core is cooled to room temperature, and as the temperature of the rotor core decreases, the rotor core cools and shrinks, so that the aperture of the mounting hole is restored, so that the shaft is subjected to pressure, so that the area of ​​the shaft opposite to the groove located on the inner wall of the mounting hole and extending axially is squeezed into the groove, forming a convex corrugated structure protruding into the groove. In this embodiment, the convex corrugated structure on the shaft can be clamped with the groove in the circumferential direction, and the ability to transmit tangential force is further enhanced, which further improves the fixing strength between the shaft and the rotor core, and can improve the torque that the shaft of the motor can withstand.

[0093] Furthermore, in another embodiment, the motor rotor includes at least two rotor cores; along the circumferential direction, the center of the groove of the rotor core and the center of the permanent magnet opposite to the groove deviate by a set angle, and the sleeve step specifically includes installing the two adjacent rotor cores in opposite directions and connecting the grooves of the two adjacent rotor cores.

[0094] Specifically, the opposite assembly directions of the two rotor cores can be understood as: the end faces of the rotor cores are respectively the first end face and the second end face, when assembling one rotor core, the shaft extends into the mounting hole of the rotor core from the direction of the first end face, and when assembling the other rotor core, the shaft extends into the mounting hole of the rotor core from the direction of the second end face. In the assembled motor rotor, if the second end face of one rotor core is opposite to the second end face of the other rotor core, the assembly directions of the two rotor cores are opposite.

[0095] In this embodiment, the assembly directions of the two rotor cores are opposite. When the permanent magnets of the two rotor cores are opposite, the grooves of the two rotor cores are staggered. The direction of the rotor cores is rotated so that the grooves of the two rotor cores are opposite. The permanent magnets of the two rotor cores can be staggered. Since there is a spacing area between two adjacent permanent magnets, the magnetic field in the above spacing area is weak, resulting in uneven magnetic field of the rotor core in the circumferential direction, which can easily cause uneven rotation of the rotor when the motor is working. In the embodiment of the present invention, the permanent magnets of the two rotor cores are staggered, and the above spacing area can be complemented with each other, so that the magnetic field of the rotor core in the circumferential direction tends to be uniform, thereby improving the uniformity of the rotation of the motor rotor and thus improving the uniformity of the rotation speed of the motor rotor.

[0096] In this embodiment, when installing the rotor core, by observing the position of the groove, the grooves of the two rotor cores are connected, so that the permanent magnets of the two rotor cores can be staggered, which is convenient for the assembly operation of the motor rotor. Specifically, the connection of the grooves of the two rotor cores means that the two grooves have overlapping parts, and the permanent magnet of at least one rotor core can cover the corresponding interval area of ​​the other rotor core. Of course, in a preferred embodiment, the grooves of the two rotor cores should be relative to each other, so as to more accurately control the deflection angle of the two rotor cores in the circumferential direction.

[0097] Based on the same inventive concept, the present invention also provides another assembly method for the motor rotor in the above scheme. Specifically, in one embodiment, the motor rotor includes a rotating shaft and a rotor core, the rotor core has a mounting hole, and the inner wall of the mounting hole has a groove, wherein the machining diameter of the rotating shaft is greater than the machining diameter of the mounting hole, and the machining depth of the groove is greater than the difference between the machining diameter of the rotating shaft and the machining hole diameter of the mounting hole. In this embodiment, the rotating shaft and the rotor core are assembled by a physical pressing process, and the assembly method includes:

[0098] In the step of pressing the rotating shaft into the rotor core, before pressing, the diameter of the rotating shaft is larger than the aperture of the mounting hole, the depth of the groove is larger than the difference between the diameter of the rotating shaft and the aperture of the mounting hole, and after pressing, the rotating shaft and the area opposite to the groove located on the inner wall of the mounting hole and extending axially form a convex ridge structure protruding into the groove.

[0099] In this technical solution, the area where the rotating shaft and the groove are opposite to each other can also form a convex ridge structure. The convex ridge structure on the rotating shaft can be clamped with the groove in the circumferential direction, and the ability to transmit tangential force is further enhanced, and the fixing strength between the rotating shaft and the rotor core is further improved, which can increase the torque that the rotating shaft of the motor can withstand.

[0100] The specific implementation of the present invention is described in detail above with reference to the accompanying drawings. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A motor rotor, comprising a rotating shaft and a rotor core sleeved on the rotating shaft, wherein the rotor core is fixed with a plurality of permanent magnets distributed along the circumferential direction, characterized in that: The rotor core comprises a mounting hole for sleeve-mounting the rotating shaft, the inner wall of the mounting hole has a groove extending in the axial direction, before sleeve-mounting, the diameter of the rotating shaft is larger than the aperture of the mounting hole, and the depth of the groove is larger than the difference between the diameter of the rotating shaft and the aperture of the mounting hole; The groove comprises a plurality of grooves distributed circumferentially along the inner wall of the mounting hole; In the circumferential direction, the center of the groove and the center of the permanent magnet opposite to the groove deviate by a set angle; The motor rotor includes at least two rotor cores. When viewed from the axial end of the rotating shaft, the assembly directions of two adjacent rotor cores are opposite and the grooves are connected. The permanent magnet of at least one rotor core covers the corresponding spacing area of ​​the other rotor core, so that the magnetic field of the rotor core tends to be uniform in the circumferential direction.

2. The motor rotor according to claim 1, characterized in that: After the rotating shaft and the rotor core are sleeved, a convex ridge structure protruding into the groove is formed in the area of ​​the rotating shaft opposite to the groove.

3. The motor rotor according to claim 2, characterized in that: The hot pressing fixing fitting stress between the rotating shaft and the rotor core is smaller than the yield strength of the rotating shaft material, and smaller than the yield strength of the rotor core material.

4. The motor rotor according to claim 1, characterized in that: The permanent magnets are arranged in such a way that the magnetic poles of adjacent permanent magnets are in opposite directions, and the number and positions of the plurality of grooves are arranged to be opposite to a group of permanent magnets having the same magnetic pole direction.

5. The motor rotor according to claim 1, characterized in that: The rotor core also includes an anti-leakage magnetic hole formed corresponding to each permanent magnet. When observed from the axial end of the rotating shaft, the cross-sectional shape of the anti-leakage magnetic hole is an isosceles triangle, and the vertex angle of the isosceles triangle points to the center position of the permanent magnet. The cross-sectional shape of the permanent magnet is a rectangle, and the groove is formed in: the extension lines of the sides at both ends of the rectangle, the extension lines of the two isosceles sides of the isosceles triangle, and the area surrounded by the edge line of the mounting hole.

6. A motor rotor, comprising a rotating shaft and a rotor core sleeved on the rotating shaft, wherein the rotor core is fixed with a plurality of permanent magnets distributed along the circumferential direction, characterized in that: The rotor core comprises a mounting hole for sleeve-mounting the rotating shaft, the inner wall of the mounting hole has a groove extending in the axial direction, the rotating shaft and the rotor core are assembled by a hot pressing process or a physical pressing process, and a convex ridge structure protruding into the groove is formed in the area where the rotating shaft is opposite to the groove; The groove comprises a plurality of grooves distributed circumferentially along the inner wall of the mounting hole; In the circumferential direction, the center of the groove and the center of the permanent magnet opposite to the groove deviate by a set angle; The motor rotor includes at least two rotor cores. When viewed from the axial end of the rotating shaft, the assembly directions of two adjacent rotor cores are opposite and the grooves are connected. The permanent magnet of at least one rotor core covers the corresponding spacing area of ​​the other rotor core, so that the magnetic field of the rotor core tends to be uniform in the circumferential direction.

7. The motor rotor according to claim 6, characterized in that: The hot pressing fixing fitting stress between the rotating shaft and the rotor core is smaller than the yield strength of the rotating shaft material, and smaller than the yield strength of the rotor core material.

8. The motor rotor according to claim 6, characterized in that: The permanent magnets are arranged in such a way that the magnetic poles of adjacent permanent magnets are in opposite directions, and the number and positions of the plurality of grooves are arranged to be opposite to a group of permanent magnets having the same magnetic pole direction.

9. The motor rotor according to claim 6, characterized in that: The rotor core also includes an anti-leakage magnetic hole formed corresponding to each permanent magnet. When observed from the axial end of the rotating shaft, the cross-sectional shape of the anti-leakage magnetic hole is an isosceles triangle, and the vertex angle of the isosceles triangle points to the center position of the permanent magnet. The cross-sectional shape of the permanent magnet is a rectangle, and the groove is formed in: the extension lines of the sides at both ends of the rectangle, the extension lines of the two isosceles sides of the isosceles triangle, and the area surrounded by the edge line of the mounting hole.

10. An electric motor, characterized in that: It comprises the motor rotor as claimed in any one of claims 1 to 9.

11. An assembly method for the motor rotor according to claim 1 or 6, characterized in that: The following steps are involved: A heating step of heating the rotor core, wherein the heating temperature and duration are such that the diameter of the mounting hole of the rotor core for sleeve mounting the rotating shaft is larger than the diameter of the rotating shaft; A step of sleeve-mounting the heated rotor core on the rotating shaft to form the motor rotor; In the cooling step of cooling the motor rotor, a convex ridge structure is formed in the area of ​​the rotating shaft opposite to the groove located on the inner wall of the mounting hole and extending in the axial direction, and the convex ridge structure protrudes into the groove.

12. The assembly method according to claim 11, characterized in that: The heating step specifically includes: heating at least two rotor cores, wherein the rotor cores are fixed with a plurality of permanent magnets distributed along the circumferential direction, and along the circumferential direction of the rotor cores, the center of the groove and the center of the permanent magnet opposite to the groove deviate by a set angle; The sleeve step specifically includes: sleeve the heated rotor cores on the rotating shaft respectively, wherein two adjacent rotor cores are installed in opposite directions, and the grooves of the at least two rotor cores are connected.

13. An assembly method for the motor rotor according to claim 1 or 6, characterized in that: The following steps are involved: The step of pressing the rotating shaft into the rotor core comprises: before pressing, the diameter of the rotating shaft is larger than the aperture of the mounting hole, the depth of the groove is larger than the difference between the diameter of the rotating shaft and the aperture of the mounting hole, and after pressing, the rotating shaft and the groove located on the inner wall of the mounting hole and extending axially form a convex ridge structure protruding into the groove.

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