Rotor structure of an electric machine and electric machine

Abstract

This application provides a rotor structure for an electric motor and the motor itself. The rotor structure includes an inner rotor core, several outer rotor cores, several sets of magnet assemblies, and several inter-pole salient poles. The outer rotor cores are separated from the inner rotor cores and are uniformly arranged circumferentially along the inner rotor cores, with an inter-pole gap between adjacent outer rotor cores. The magnet assemblies are located between the outer rotor cores and the inner rotor cores. The inter-pole salient poles are located at the outer edge of the inner rotor cores, and each inter-pole salient pole extends into its corresponding inter-pole gap. Along the radial direction of the rotor structure, there is a preset gap between the inter-pole salient poles and the outer circumferential surface of the outer rotor cores. The positions of the magnet assemblies and the inter-pole gaps are provided with clearance gaps that allow the inter-pole salient poles to pass through. This effectively increases the magnetic reluctance of the demagnetizing magnetic field circuit of the rotor structure when the magnetic isolation bridge is eliminated, thereby weakening the demagnetizing magnetic field, reducing eddy current losses of the magnet assemblies, and reducing the risk of thermal demagnetization of the magnet assemblies, thus improving motor vibration and noise.

Description

Technical Field

[0001] This application relates to the field of motor technology, and more particularly to a rotor structure for an electric motor and the motor itself. Background Technology

[0002] Currently, motors with built-in rotors are equipped with magnetic isolation bridges. These bridges typically exhibit significant magnetic leakage, which reduces the utilization rate of the motor's magnets and consequently increases the cost of the motor's magnets.

[0003] To address this, patent CN213402602U discloses a permanent magnet synchronous motor and a permanent magnet synchronous motor rotor structure. The permanent magnet synchronous motor rotor structure includes a rotor core and several magnetic pole structures that are spaced apart and independently arranged along the circumference of the rotor core. Each magnetic pole structure includes a magnetic guide block and at least one magnet. The magnetic guide block is disposed on the surface of the magnet, and the magnet is located between the rotor core and the magnetic guide block, separating the rotor core from the magnetic guide block. Because the magnetic pole structures in this device are spaced apart, that is, the magnetic guide blocks are spaced apart and independently separated from each other, there is no magnetic isolation bridge, thereby improving the utilization rate of the magnet.

[0004] However, after the magnetic bridge is removed from the motor, the eddy current loss of the magnet increases sharply, the risk of thermal demagnetization of the magnet increases, and ultimately causes serious motor vibration and noise problems. Utility Model Content

[0005] The purpose of this application is to provide a rotor structure for an electric motor and an electric motor in order to solve the problem of how to avoid causing serious motor vibration and noise.

[0006] In a first aspect, this application provides a rotor structure for an electric motor, comprising:

[0007] The rotor inner core is located on the inner circumference of the rotor structure;

[0008] Several rotor outer iron cores are separated from the rotor inner iron core and are evenly arranged along the circumference of the rotor inner iron core, with an interpole spacing between two adjacent rotor outer iron cores;

[0009] Several sets of magnet assemblies are located between the outer iron core of the rotor and the inner iron core of the rotor. The multiple sets of magnet assemblies are evenly spaced along the circumference of the rotor structure and correspond one-to-one with the multiple outer iron cores of the rotor.

[0010] Several inter-pole salient poles are located on the outer edge of the inner iron core of the rotor, and each inter-pole salient pole extends into the corresponding inter-pole gap; along the radial direction of the rotor structure, there is a preset gap between the inter-pole salient pole and the outer peripheral surface of the outer iron core of the rotor; the position of the magnet assembly corresponding to the inter-pole gap is provided with a clearance gap that allows the inter-pole salient pole to pass through.

[0011] In some embodiments, the preset gap h satisfies: 0.7m ≤ h ≤ 0.9m; where m is the air gap length of the motor.

[0012] In some embodiments, the outer peripheral surface of the rotor outer core is provided with at least one auxiliary groove.

[0013] In some embodiments, the outer peripheral surface of the inter-pole salient pole is an arc surface, and the center of the arc surface coincides with the center of the rotor structure; or, the outer peripheral surface of the inter-pole salient pole is a plane.

[0014] In some embodiments, the side of the inter-electrode convex pole near the clearance interval is planar.

[0015] In some embodiments, the rotor inner core and the inter-pole salient pole are integrally formed.

[0016] In some embodiments, the magnet assembly is in the form of a straight line, a V-shape, a U-shape, a W-shape, or a tile shape.

[0017] In some embodiments, a first positioning part is provided on the side of the rotor outer core facing the magnet assembly, for cooperating with the magnet assembly to assemble and position the magnet assembly;

[0018] And / or, the inner core of the rotor is provided with a second positioning part on the side facing the magnet assembly, for cooperating with the magnet assembly to assemble and position the magnet assembly.

[0019] In some embodiments, a fixing sleeve is further included, which is sleeved on the outer periphery of the rotor outer core.

[0020] Secondly, embodiments of this application also provide an electric motor, including the rotor structure of the electric motor described above.

[0021] The beneficial effects of the technical solution provided by this utility model embodiment are:

[0022] The rotor structure and motor provided in this application include an inner rotor core, several outer rotor cores, several sets of magnet assemblies, and several inter-pole salient poles. The outer rotor cores are separated from the inner rotor cores and are uniformly arranged circumferentially along the inner rotor core, with an inter-pole gap between adjacent outer rotor cores. The magnet assemblies are located between the outer rotor cores and the inner rotor cores. The inter-pole salient poles are located at the outer edge of the inner rotor core, and each inter-pole salient pole extends into its corresponding inter-pole gap. A preset gap exists between the inter-pole salient poles and the outer circumferential surface of the outer rotor core along the radial direction of the rotor structure. The positions of the magnet assemblies and inter-pole gaps are provided with clearance intervals allowing the inter-pole salient poles to pass through. This arrangement effectively increases the magnetic reluctance of the demagnetizing magnetic field circuit of the rotor structure without eliminating the magnetic isolation bridge, thereby weakening the demagnetizing magnetic field and reducing eddy current losses in the magnet assemblies. This reduces the risk of thermal demagnetization of the magnet assemblies and ultimately improves the noise problem of motor vibration to a certain extent. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic cross-sectional view of an electric motor provided in an embodiment of this application;

[0025] Figure 2 for Figure 1 A partial structural diagram of the rotor structure of the motor shown;

[0026] Figure 3 for Figure 2 A magnified view of a portion at point A;

[0027] Figure 4 for Figure 1 A partial structural diagram of the rotor structure of the motor shown;

[0028] Figure 5 for Figure 1 The diagram shows a partial structural schematic of the motor.

[0029] Figure 6 This is a partial cross-sectional schematic diagram of another motor provided in an embodiment of this application;

[0030] Figure 7 for Figure 6 The diagram shows a partial structural schematic of the motor.

[0031] Figure 8 for Figure 7A magnified view of the area at point B;

[0032] Figure 9 for Figure 6 A partial structural diagram of the rotor structure of the motor shown;

[0033] Figure 10 This is a schematic diagram comparing the torque and torque ripple of the motor shown in the embodiment of this application with that of a conventional motor;

[0034] Figure 11 for Figure 1 The diagram shows the variation curves of the preset clearance, torque, and torque ripple rate of the motor.

[0035] Figure 12 for Figure 1 The diagram shows the variation curves of the preset gap, eddy current loss, and core loss of the motor.

[0036] Figure 13 for Figure 6 The diagram shows the variation curves of the preset clearance, torque, and torque ripple rate of the motor.

[0037] Figure 14 for Figure 6 The diagram shows the variation curves of the preset gap, eddy current loss, and core loss of the motor.

[0038] Figure label:

[0039] 100. Rotor outer core; 110. Interpole spacing; 120. First positioning part; 130. Auxiliary slot; 200. Rotor inner core; 220. Interpole salient pole; 230. Second positioning part; 300. Preset gap; 400. Magnet assembly; 410. Clearance gap; 500. Stator; 600. Fixing sleeve. Detailed Implementation

[0040] In the embodiments of this application, the terms "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," "third," "fourth," "fifth," and "sixth" may explicitly or implicitly include one or more of that feature.

[0041] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0042] In the description of the embodiments of this application, specific features, structures, materials or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0043] Reference Figures 1 to 9 As shown, this application provides a rotor structure for an electric motor, including an inner rotor core 200, several outer rotor cores 100, several sets of magnet assemblies 400, and several inter-pole salient poles 220.

[0044] Specifically, the inner iron core 200 of the rotor is located on the inner circumference of the rotor structure.

[0045] Several rotor outer iron cores 100 are separated from rotor inner iron cores 200 and are evenly arranged along the circumference of rotor inner iron cores 200, with an interpole spacing 110 between two adjacent rotor outer iron cores 100.

[0046] Several sets of magnet assemblies 400 are located between the outer iron core 100 and the inner iron core 200 of the rotor. The multiple sets of magnet assemblies 400 are evenly spaced along the circumference of the rotor structure and correspond one-to-one with multiple outer iron cores 100 of the rotor.

[0047] Several inter-pole salient poles 220 are located on the outer edge of the inner iron core 200 of the rotor, and each inter-pole salient pole 220 extends into the corresponding inter-pole gap 110. Along the radial direction of the rotor structure, there is a preset gap 300 between the inter-pole salient pole 220 and the outer peripheral surface of the outer iron core 100 of the rotor. The magnet assembly 400 is provided with a clearance gap 410 at the position corresponding to the inter-pole gap 110, which allows the inter-pole salient pole 220 to pass through.

[0048] In specific implementation, refer to Figure 1 As shown, the rotor structure includes several outer rotor cores 100 and inner rotor cores 200. The outer rotor cores 100 are evenly arranged circumferentially along the inner rotor cores 200 and form a shape as shown. Figure 1 The annular structure shown has an inner iron core 200 located on the inner circumference of the rotor structure, specifically in the inner ring of the annular structure, and several sets of magnet assemblies 400 located between the inner iron core 200 and the outer iron core 100 to form a complete rotor structure.

[0049] In this embodiment, an inter-pole gap 110 is formed between two adjacent rotor outer cores 100 to accommodate the inter-pole salient pole 220. The inter-pole salient pole 220 can extend into the inter-pole gap 110. The magnet assembly 400 located between the rotor outer core 100 and the rotor inner core 200 has a clearance gap 410 at a position corresponding to the inter-pole gap 110, allowing the inter-pole salient pole 220 to pass through. A preset gap 300 is provided between the inter-pole salient pole 220 and the outer peripheral surface of the rotor outer core 100 in the radial direction of the rotor structure. The setting of the preset gap 300 can effectively increase the magnetic reluctance of the demagnetizing magnetic field circuit of the rotor structure, thereby weakening the demagnetizing magnetic field, which can reduce the eddy current loss of the magnet assembly 400, thereby reducing the risk of thermal demagnetization of the magnet assembly 400, and ultimately improving the noise problem of motor vibration to a certain extent.

[0050] Furthermore, in this embodiment, by placing an inter-pole salient pole 220 within the inter-pole spacing 110, the Q-axis inductance of the rotor structure is increased to a certain extent, thereby increasing the torque ratio. This reduces the amount of magnet assembly 400 used, effectively lowering the cost of the motor. Simultaneously, the inter-pole salient pole 220 within the inter-pole spacing 110 not only acts as a transition in the inter-pole magnetic field, reducing torque fluctuations and improving the smoothness of motor operation, but also increases harmonic reluctance, significantly reducing the losses of the magnet assembly 400 and improving motor efficiency.

[0051] Tests revealed that, as referenced Figure 10 As shown, for a certain model of motor with the same parameters, the rotor structure of this embodiment eliminates the traditional magnetic bridge design. This allows the motor torque of this embodiment to be increased from 70.7 Nm to 76.6 Nm under the same motor parameters as the traditional motor, with a torque increase of 8.3%. At the same time, the torque fluctuation rate is reduced from 3.92% to 2.43%. In other words, the stability of the motor can be effectively improved while reducing the cost of the motor.

[0052] Specific reference Figure 10 As shown, where Figure 10 S1 is a graph showing the torque of the motor in this embodiment changing over time, and S2 is a graph showing the torque of a conventional motor changing over time. Figure 10 As can be seen, the torque of the motor in this embodiment is greater than that of a traditional motor, and the torque fluctuation range (the fluctuation range of the curve) is also significantly smaller than that of a traditional motor.

[0053] The following table compares the performance of the motor adapted to the rotor structure of this embodiment with that of a conventional motor with a magnetic bridge:

[0054]

[0055] In addition, the specific parameters and models of the motors used in the tests are shown in the table below:

[0056]

[0057] As can be seen from the above, in this embodiment of the rotor structure, a plurality of rotor outer iron cores 100 are uniformly arranged along the circumference of rotor inner iron core 200, and there is an interpole spacing 110 between two adjacent rotor outer iron cores 100. The rotor inner iron core 200 is located on the inner circumference of the rotor structure, and the magnet assembly 400 is located between the rotor outer iron core 100 and the rotor inner iron core 200. Furthermore, the outer edge of the inner iron core 200 of the rotor is provided with multiple inter-pole salient poles 220 arranged circumferentially. Each inter-pole salient pole 220 passes through the clearance interval 410 of the magnet assembly 400 and is located within the corresponding inter-pole interval 110. In the radial direction of the rotor structure, there is a preset gap 300 between the inter-pole salient pole 220 and the outer peripheral surface of the outer iron core 100 of the rotor. This arrangement can effectively increase the magnetic reluctance of the demagnetizing magnetic field circuit of the rotor structure without the need to set up a magnetic isolation bridge, so as to weaken the demagnetizing magnetic field, thereby reducing the eddy current loss of the magnet assembly 400, reducing the risk of thermal demagnetization of the magnet assembly 400, and ultimately improving the noise problem of motor vibration to a certain extent.

[0058] Reference Figure 1 As shown, in some embodiments, the size of the preset gap 300 between any two pole spacings 110 and the outer peripheral surface of the rotor outer core 100 is the same.

[0059] In other words, in this embodiment, the size of the preset gap between the pole salient 220 and the outer peripheral surface of the rotor outer iron core can be set to be the same in all pole intervals. This not only facilitates processing and manufacturing but also improves the smoothness of motor operation.

[0060] Reference Figure 3 and Figure 8 As shown, in some embodiments, the dimension h of the preset gap 300 satisfies: 0.7m≤h≤0.9m; where m is the air gap length of the motor.

[0061] In this embodiment, by reasonably setting the dimensional relationship between the preset gap 300 and the air gap length, the loss of the rotor structure and the eddy current loss of the magnet assembly 400 can be effectively reduced, thereby effectively improving the motor efficiency while the torque loss is not significant and the torque fluctuation can be optimized.

[0062] For example, when the air gap length is 0.65 mm, the size h of the preset gap 300 can be 0.46 mm, 0.5 mm, or 0.58 mm.

[0063] Reference Figure 3 , Figure 4 , Figure 8 and Figure 9 As shown, at least one auxiliary slot 130 is provided on the outer circumferential surface of the rotor outer iron core 100 to reduce the content of magnetic field harmonics, thereby reducing cogging torque and torque fluctuation, increasing torque output, and thus improving the efficiency of the motor.

[0064] For example, two auxiliary slots 130 can be provided on the outer circumferential surface of each rotor outer core 100, and the two auxiliary slots 130 can be along the magnetic pole center line (refer to...). Figure 2 The y2 shown is symmetrically set.

[0065] Reference Figure 2 As shown, in some embodiments, the inter-electrode salient 220 is oriented along the central axis of the inter-electrode spacing 110 (see reference). Figure 2 The y1 shown is a symmetrical structure with a symmetrical axis, which helps to improve the smoothness of motor operation.

[0066] Reference Figures 1 to 9 As shown, in some embodiments, all inter-pole salient poles 220 are centrally symmetrically arranged with respect to the center of the rotor structure, that is, all inter-pole salient poles 220 have the same outline shape, size, etc., and the distance between them and the center of the rotor structure is also consistent. This facilitates the assembly between the outer iron core 100 and the inner iron core 200 of the rotor without the need for positioning before assembly, simplifies the manufacturing process, and helps to control the consistency of the preset gap 300 to ensure the smooth operation of the motor.

[0067] Reference Figures 1 to 9 As shown, in some embodiments, the outer peripheral surface of the inter-pole salient pole 220 is arc-shaped, and the center of the arc coincides with the center of the rotor structure; or, the outer peripheral surface of the inter-pole salient pole 220 is planar.

[0068] In this embodiment, the outer peripheral surface of the inter-pole salient pole is arc-shaped, and this arc-shaped surface is parallel and spaced apart from the arc-shaped surface of the outer peripheral surface of the rotor outer iron core 100. This helps to ensure the consistency of the preset gap 300, thereby improving the smooth operation of the motor.

[0069] Alternatively, in other implementations, the outer peripheral surface of the inter-electrode salient 220 can also be a plane to simplify the manufacturing process.

[0070] In some embodiments, the side of the inter-pole salient pole 220 near the clearance interval 410 can be set to be flat, which can simplify the manufacturing process and make the magnetic field distribution more uniform.

[0071] In some embodiments, the rotor inner core 200 and the inter-pole salient pole 220 are integrally formed, which saves manufacturing steps and improves the overall structural strength of the rotor inner core 200. Alternatively, in other implementations, the rotor inner core 200 and the inter-pole salient pole 220 can be formed separately and then snapped together.

[0072] Reference Figures 1 to 5 As shown, the magnet assembly 400 can be in the form of a straight line, a V-shape, a U-shape, a W-shape, or a tile shape.

[0073] When the magnet assembly 400 has a straight-line structure, the relationship between the corresponding motor performance and the preset gap 300 is shown in the table below:

[0074]

[0075] When the magnet assembly 400 has a V-shaped structure, the relationship between the corresponding motor performance and the preset gap 300 is shown in the table below:

[0076]

[0077] Specifically, for the magnet assembly 400 with a straight-line structure, the curves S3 showing the change in the size h of the preset gap 300 with the motor torque and S4 showing the change in the size h of the preset gap 300 with the torque fluctuation can be referenced. Figure 11 As shown.

[0078] For the magnet assembly 400 with a straight-line structure, the curves S5 showing the relationship between the size h of the preset gap 300 and the eddy current loss of the magnet assembly 400, and S6 showing the relationship between the size h of the preset gap 300 and the core loss of the rotor structure, can be referenced. Figure 12 As shown.

[0079] Specifically, for the V-shaped structure of the magnet assembly 400, the curves S7 showing the change between the dimension h of the preset gap 300 and the motor torque, and S8 showing the change between the dimension h of the preset gap 300 and the torque fluctuation, can be referenced. Figure 13 As shown.

[0080] For the V-shaped structure of the magnet assembly 400, the curves S9 showing the relationship between the size h of the preset gap 300 and the eddy current loss of the magnet assembly 400, and S10 showing the relationship between the size h of the preset gap 300 and the core loss of the rotor structure, can be referenced. Figure 14 As shown. Therefore, in practical applications, the specific size h of the preset gap 300 can be determined according to the requirements of eddy current loss, core loss, torque, and torque fluctuation rate settings.

[0081] Reference Figure 2As shown, in some embodiments, a first positioning part 120 is provided on the side of the rotor outer iron core 100 facing the magnet assembly 400, which is used to cooperate with the magnet assembly 400 to assemble and position the magnet assembly 400, so as to realize the positioning assembly between the magnet assembly 400 and the rotor outer iron core 100, and improve the assembly accuracy and efficiency.

[0082] For example, the first positioning part 120 may include a first positioning groove recessed in a direction away from the magnet assembly 400, the contour shape of the first positioning groove being adapted to the contour shape of the magnet assembly 400, so as to accommodate a portion of the magnet assembly 400 in the first positioning groove to achieve a positioning operation.

[0083] Alternatively, in other implementations, the first positioning part 120 may include a first positioning hole provided on the rotor outer iron core 100 and a first positioning protrusion provided on the magnet assembly 400, and the positioning operation between the rotor outer iron core 100 and the magnet assembly 400 is realized by the cooperation of the first positioning hole and the first positioning protrusion.

[0084] Reference Figure 2 As shown, in some embodiments, a second positioning part 230 is provided on the side of the rotor inner core 200 facing the magnet assembly 400, which is used to cooperate with the magnet assembly 400 to assemble and position the magnet assembly 400, so as to realize the positioning and assembly between the magnet assembly 400 and the rotor inner core 200, and improve the assembly accuracy and efficiency.

[0085] For example, the second positioning part 230 may include a second positioning groove recessed in a direction away from the magnet assembly 400, the contour shape of the second positioning groove being adapted to the contour shape of the magnet assembly 400, so as to accommodate a portion of the magnet assembly 400 in the second positioning groove to achieve a positioning operation.

[0086] Alternatively, in other implementations, the second positioning part 230 may include a second positioning hole provided on the rotor inner core 200 and a second positioning protrusion provided on the magnet assembly 400, thereby realizing the positioning operation between the rotor inner core 200 and the magnet assembly 400 through the cooperation of the second positioning hole and the second positioning protrusion.

[0087] Reference Figure 1 As shown, in some embodiments, the rotor structure also includes a fixing sleeve 600, which is sleeved on the outer periphery of the rotor outer core 100. The fixing sleeve 600 serves to fix the rotor outer core 100 of the rotor structure and facilitates the assembly between the stator and rotor structures of the motor.

[0088] In practice, the fixed sleeve 600 and the outer iron core 100 of the rotor can be tightly fitted, such as an interference fit. In this case, the preset gap 300 can also be understood as the radial dimension between the outer peripheral surface of the pole salient 220 and the inner wall surface of the fixed sleeve 600 along the rotor structure.

[0089] For example, the fixing sleeve 600 can be a stainless steel sleeve, and the wall thickness of the fixing sleeve 600 can be about 0.25mm to ensure that the fixing sleeve 600 has sufficient structural strength.

[0090] Refer to Figure 9 As shown, this application embodiment also provides an electric motor, including the rotor structure of the electric motor described above.

[0091] The specific structure and implementation principle of the motor rotor structure in this embodiment are the same as those of the motor rotor structure provided in the above embodiments, and can bring the same or similar technical effects. They will not be described in detail here, but can be referred to the description of the above embodiments.

[0092] In addition, in this embodiment, the stator 500 of the motor can adopt a skewed slot design with an inclination degree of 3.33°. This can also weaken the harmonic magnetic field generated by the motor itself, thereby reducing the cogging torque and improving the smoothness of motor operation.

[0093] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A rotor structure for an electric motor, characterized in that, include: The rotor inner core (200) is located on the inner circumference of the rotor structure; A plurality of rotor outer cores (100) are separated from the rotor inner core (200) and are uniformly arranged along the circumference of the rotor inner core (200), and there is an interpole spacing (110) between two adjacent rotor outer cores (100); Several sets of magnet assemblies (400) are located between the outer iron core (100) of the rotor and the inner iron core (200) of the rotor. The multiple sets of magnet assemblies (400) are evenly spaced along the circumference of the rotor structure and correspond one-to-one with the multiple outer iron cores (100) of the rotor. A plurality of inter-pole salient poles (220) are located on the outer edge of the inner core (200) of the rotor, and each inter-pole salient pole (220) extends into the corresponding inter-pole gap (110) in turn; along the radial direction of the rotor structure, there is a preset gap (300) between the inter-pole salient pole (220) and the outer peripheral surface of the outer core (100) of the rotor; the magnet assembly (400) is provided with a clearance gap (410) at the position corresponding to the inter-pole gap (110) so that the inter-pole salient pole (220) can pass through.

2. The rotor structure according to claim 1, characterized in that, The dimension h of the preset gap (300) satisfies: 0.7m≤h≤0.9m; where m is the air gap length of the motor.

3. The rotor structure according to claim 1, characterized in that, The outer peripheral surface of the rotor outer core (100) is provided with at least one auxiliary groove (130).

4. The rotor structure according to claim 1, characterized in that, The outer peripheral surface of the inter-pole salient pole (220) is arc-shaped, and the center of the arc coincides with the center of the rotor structure; or, the outer peripheral surface of the inter-pole salient pole (220) is planar.

5. The rotor structure according to claim 4, characterized in that, The side of the inter-pole salient pole (220) near the clearance interval (410) is planar.

6. The rotor structure according to any one of claims 1-5, characterized in that, The rotor inner core (200) and the inter-pole salient pole (220) are integrally formed.

7. The rotor structure according to claim 6, characterized in that, The magnet assembly (400) is in the form of a straight line, a V-shape, a U-shape, a W-shape, or a tile shape.

8. The rotor structure according to claim 7, characterized in that, The rotor outer core (100) has a first positioning part (120) on the side facing the magnet assembly (400), which is used to cooperate with the magnet assembly (400) to assemble and position the magnet assembly (400). And / or, the inner core (200) of the rotor is provided with a second positioning part (230) on the side facing the magnet assembly (400), for cooperating with the magnet assembly (400) to assemble and position the magnet assembly (400).

9. The rotor structure according to claim 8, characterized in that, It also includes a fixing sleeve (600), which is sleeved on the outer periphery of the rotor outer iron core (100).

10. An electric motor, characterized in that, Includes the rotor structure of the motor as described in any one of claims 1 to 9.

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