Motor rotor, permanent magnet motor, compressor and manufacturing method

Abstract

The invention relates to the technical field of motors, and provides a motor rotor, a permanent magnet motor, a compressor and a manufacturing method. The rotor core is provided with a plurality of mounting parts arranged along the circumferential direction, each mounting part comprises a plurality of magnetic steel grooves arranged in sequence, and the plurality of magnetic steel grooves are arranged according to a cosine function; the plurality of magnetic poles and the plurality of mounting parts are arranged in a one-to-one correspondence manner, and each magnetic pole comprises a plurality of permanent magnets corresponding to the plurality of magnetic steel grooves in a one-to-one correspondence manner. According to the invention, the installation part adopts the plurality of magnetic steel grooves which are arranged in sequence, and the plurality of magnetic steel grooves are arranged according to the cosine function, so that the plurality of permanent magnets arranged in the plurality of magnetic steel grooves are arranged according to the cosine function, the magnetic poles are of a multi-section cosine function arrangement structure, and the distribution of an air-gap magnetic field is closer to sine waves; on the premise that the effective value of the back electromotive force is not reduced, the harmonic content of the back electromotive force is remarkably reduced, and then the performance of the motor is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a motor rotor, a permanent magnet motor, a compressor and a manufacturing method thereof. Background Art

[0002] Back EMF is one of the core indicators of a motor. The effective value of back EMF directly affects the motor's ability to convert electrical energy into useful energy. A higher effective back EMF value usually means that the motor can output greater torque at the same current, thereby improving power density and torque performance, which is crucial for applications such as electric vehicles and industrial servos. In addition, a high back EMF helps improve the voltage utilization of the motor, allowing the motor to maintain a high output power at high speeds and widen the constant power speed regulation range. However, in order to achieve a higher effective back EMF value, the interior permanent magnet synchronous motor (IPMSM) usually leads to a higher back EMF harmonic content, resulting in significant torque pulsation, additional iron and copper losses, and increased electromagnetic vibration noise during operation, thereby worsening the vibration and noise of the motor.

[0003] In the existing technology, a V-shaped magnetic steel slot structure is used to optimize the magnetic steel slot angle, permanent magnet width and magnetic isolation bridge length to achieve the effect of reducing back EMF harmonics; however, while this method reduces the back EMF harmonics, it will also cause the effective value of the back EMF to decrease, thereby reducing the motor performance. Summary of the Invention

[0004] The present invention provides a motor rotor, a permanent magnet motor and a manufacturing method thereof, which are used to solve the defect in the prior art that reducing the back EMF harmonics will lead to a decrease in the effective value of the back EMF, thereby reducing the performance of the motor. It is possible to significantly reduce the back EMF harmonic content and improve the motor performance without reducing the effective value of the back EMF.

[0005] The present invention provides a motor rotor, comprising: A rotor core having a plurality of mounting components arranged along a circumferential direction, each mounting component including a plurality of magnetic steel slots arranged in sequence, wherein the plurality of magnetic steel slots are arranged according to a cosine function; A plurality of magnetic poles are arranged in one-to-one correspondence with the plurality of mounting components, and each of the magnetic poles includes a plurality of permanent magnets in one-to-one correspondence with the plurality of magnetic steel slots.

[0006] According to a motor rotor provided by the present invention, the cosine function is ; in, represents the first coefficient, represents the second coefficient, Represents a constant.

[0007] According to the present invention, a motor rotor is provided. satisfy: ; and / or, satisfy: ; and / or, and satisfy: ; Where R is the radius of the rotor core and P is the number of magnetic poles.

[0008] According to a motor rotor provided by the present invention, a line connecting the center of the mounting component and the axis of the rotor core forms a d-axis, and the mounting component is an axisymmetric structure with the d-axis as the axis of symmetry.

[0009] The present invention also provides a permanent magnet motor, comprising: The motor stator comprises a stator core and a stator winding arranged on the stator core; In any one of the above motor rotors, the stator core and the rotor core cooperate with each other.

[0010] The present invention also provides a compressor, comprising: A permanent magnet motor as described in any one of the above.

[0011] The present invention also provides a method for manufacturing a motor rotor, comprising: A plurality of mounting components are formed on the rotor core and arranged along the circumferential direction, each of the mounting components includes a plurality of magnetic steel slots arranged in sequence, and the plurality of magnetic steel slots are arranged according to a cosine function; A plurality of magnetic poles are arranged on the plurality of mounting components in a one-to-one correspondence, and each of the magnetic poles includes a plurality of permanent magnets corresponding to the plurality of magnetic steel slots in a one-to-one correspondence.

[0012] According to a method for manufacturing a motor rotor provided by the present invention, the step of arranging any of the plurality of mounting components arranged circumferentially on the rotor core comprises: Determine the number of magnetic steel slots; Based on the cosine function, determine multiple different function points; Based on the plurality of function points, determining the direction and size of each magnetic steel slot; Based on the directions and sizes of the magnetic steel slots, mounting components are formed on the rotor core.

[0013] According to a motor rotor manufacturing method provided by the present invention, determining multiple different function points based on a cosine function includes: Construct a coordinate system, wherein the d-axis is used as the vertical axis and the horizontal axis is perpendicular to the d-axis and passes through the axis of the rotor core; Based on the cosine function and the coordinate system, multiple function points with different horizontal coordinates are determined, and the maximum horizontal coordinate of the function point is , satisfy: , R represents the radius of the rotor core, and P represents the number of magnetic poles.

[0014] According to a method for manufacturing a motor rotor provided by the present invention, determining the direction and size of each magnetic steel slot based on the plurality of function points includes: Based on the number of magnetic steel slots, determining a corresponding target cosine point from a plurality of the function points; Determine the magnetic steel slot direction corresponding to each target cosine point based on the target cosine point or the function points adjacent to each target cosine point; The size of each magnetic steel slot is determined based on the offset distance and the direction of the magnetic steel slot.

[0015] The motor rotor provided by the present invention adopts a plurality of magnetic steel slots arranged in sequence through the mounting components, and the plurality of magnetic steel slots are arranged according to a cosine function, so that the plurality of permanent magnets arranged in the plurality of magnetic steel slots are arranged in a cosine function, so that the magnetic poles have a multi-segment, cosine function arrangement structure, so that the air gap magnetic field distribution is closer to a sine wave, and it is possible to significantly reduce the back electromotive force harmonic content without reducing the effective value of the back electromotive force, thereby improving the motor performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is one of the structural schematic diagrams of the motor rotor provided by the present invention.

[0018] Figure 2 This is the second structural schematic diagram of the motor rotor provided by the present invention.

[0019] Figure 3 This is one of the flow charts of the motor rotor manufacturing method provided by the present invention.

[0020] Figure 4 This is the second flow chart of the motor rotor manufacturing method provided by the present invention.

[0021] Figure 5 This is the third flow chart of the motor rotor manufacturing method provided by the present invention.

[0022] Figure 6This is the fourth flow chart of the motor rotor manufacturing method provided by the present invention.

[0023] Figure 7 This is a back electromotive force waveform diagram of the motor provided by the present invention.

[0024] Figure 8 This is the back EMF waveform of the existing motor.

[0025] Reference numerals: 10. Rotor core; 11. Mounting components; 111. Magnetic steel slot; 101. First magnetic steel slot; 102. Second magnetic steel slot; 103. Third magnetic steel slot; 20. Magnetic pole; 21. Permanent magnet; 30. Stator core; 40. Stator winding. DETAILED DESCRIPTION

[0026] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0027] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0028] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0029] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0030] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0031] The following combination Figure 1 and Figure 2 The electric machine rotor of the present invention is described.

[0032] An embodiment of the present invention provides a motor rotor, such as Figure 1 and Figure 2 As shown, the motor rotor includes a rotor core 10 and a plurality of magnetic poles 20; the rotor core 10 has a plurality of mounting components 11 arranged along the circumferential direction, each mounting component 11 includes a plurality of magnetic steel slots 111 arranged in sequence, and the plurality of magnetic steel slots 111 are arranged according to a cosine function; the plurality of magnetic poles 20 are arranged in a one-to-one correspondence with the plurality of mounting components 11, and each magnetic pole 20 includes a plurality of permanent magnets 21 corresponding one-to-one to the plurality of magnetic steel slots 111.

[0033] It is understood that a plurality of mounting components 11 are provided on the end surface of the rotor core 10 along the circumference of the rotor core 10. The number of mounting components 11 is equal to the number of magnetic poles 20, and the positions correspond one-to-one. The plurality of magnetic poles 20 are correspondingly embedded in the plurality of mounting components 11. It should be noted that the number of magnetic poles 20 is an even number, and every two magnetic poles 20 are symmetrically arranged around the axis of the rotor core 10 to form a permanent magnet unit, so that at least one permanent magnet unit is arranged on the rotor core 10; and the magnetic properties of two adjacent magnetic poles 20 along the circumference of the rotor core 10 are opposite.

[0034] Each mounting component 11 includes a plurality of magnetic steel slots 111 arranged in sequence, and a plurality of permanent magnets 21 are correspondingly embedded in the plurality of magnetic steel slots 111 . The plurality of magnetic steel slots 111 are arranged according to a cosine function, that is, the plurality of permanent magnets 21 are arranged in a cosine function.

[0035] The multiple permanent magnets 21 in the multiple magnetic steel slots 111 of each mounting component 11 form a magnetic pole 20, so that the magnetic pole 20 adopts a multi-segment, cosine function arrangement structure to optimize the pole arc coefficient, so that the air gap magnetic field distribution is closer to a sine wave, and a back electromotive force with a higher effective value, lower harmonic content, and higher sinusoidality is obtained; in this way, the multiple magnetic steel slots 111 of the mounting component 11 are designed in the form of a cosine function, that is, the structure of the magnetic pole 20 is designed, which can achieve a significant reduction in the harmonic content of the back electromotive force without reducing the effective value of the back electromotive force, thereby improving the performance of the motor.

[0036] The motor rotor provided by an embodiment of the present invention adopts a plurality of magnetic steel slots 111 arranged in sequence through the mounting component 11, and the plurality of magnetic steel slots 111 are arranged according to a cosine function, so that the plurality of permanent magnets 21 arranged in the plurality of magnetic steel slots 111 are arranged in a cosine function, so that the magnetic poles 20 are a multi-segment, cosine function arrangement structure, so that the air gap magnetic field distribution is closer to a sine wave, and it is possible to significantly reduce the back electromotive force harmonic content without reducing the effective value of the back electromotive force, thereby improving the motor performance.

[0037] In one embodiment of the present invention, the cosine function is as follows (1): (1) in, represents the first coefficient, represents the second coefficient, Represents a constant.

[0038] Optional, Satisfies the following formula (2), Satisfies the following formula (3), and The following formula (4) is satisfied: (2) (3) (4) Where R is the radius of the rotor core and P is the number of magnetic poles.

[0039] It should be noted that, in other embodiments, 、 、 At least one of the above formulas (2), (3), and (4) may be selected.

[0040] In one embodiment of the present invention, Figure 2 As shown, the line connecting the center of the mounting component 11 and the axis of the rotor core 10 forms the d-axis, and the mounting component 11 is an axisymmetric structure with the d-axis as the symmetry axis.

[0041] It can be understood that the geometric shapes of the mounting component 11 on both sides of the d-axis are mirror-symmetrical, thereby ensuring that the magnetic field distribution is symmetrical about the d-axis; the mounting component 11 is an axisymmetric structure, and correspondingly, the magnetic pole 20 mounted on the mounting component 11 is also an axisymmetric structure with the d-axis as the symmetry axis, ensuring the dynamic balance of the motor rotor during high-speed rotation and avoiding vibration noise caused by uneven mass distribution.

[0042] Optionally, the number of the magnetic steel slots 111 of each mounting component 11 may be 4 to 8.

[0043] In this embodiment, Figure 1 and Figure 2 As shown, the mounting component 11 includes five sequentially arranged magnetic steel slots 111, specifically including a first magnetic steel slot 101, two second magnetic steel slots 102, and two third magnetic steel slots 103. The two second magnetic steel slots 102 are symmetrically arranged on either side of the first magnetic steel slot 101, and the two third magnetic steel slots 103 are symmetrically arranged on either side of the first magnetic steel slot 101. The second magnetic steel slot 102 is located between the first magnetic steel slot 101 and the third magnetic steel slot 103. Thus, the third magnetic steel slot 103, the second magnetic steel slot 102, the first magnetic steel slot 101, another second magnetic steel slot 102, and another third magnetic steel slot 103 are arranged according to a cosine function. Correspondingly, the magnetic pole 20 includes five permanent magnets 21, each of which is embedded in the five magnetic steel slots 111.

[0044] Optionally, the magnetic steel slot 111 is rectangular; correspondingly, the permanent magnet 21 (magnetic steel) is also rectangular.

[0045] It should be noted that the existing method of reducing back EMF harmonics by increasing the magnet thickness and the specific magnet angle increases the cost due to the increased magnet thickness. However, the magnetic pole 20 of this embodiment adopts a multi-segment rectangular magnet cosine regular arrangement. Compared with the existing V-shaped magnet structure, it can provide better motor performance, reduce magnet eddy current loss, and reduce magnet temperature rise without increasing cost.

[0046] An embodiment of the present invention further provides a permanent magnet motor, which includes a motor stator and a motor rotor. The motor rotor adopts the motor rotor provided by any of the above embodiments; wherein the stator core 30 cooperates with the rotor core 10.

[0047] Specifically, the motor stator includes a stator core 30 and a stator winding 40 arranged on the stator core 30; the stator core 30 is sleeved on the rotor core 10, so that the motor rotor is installed in the motor stator, and the motor rotor is driven to rotate through the motor stator.

[0048] It should be noted that existing permanent magnet motors, in pursuit of a higher back-EMF effective value, often have high back-EMF harmonic content, leading to significant torque ripple, additional iron and copper losses, and increased electromagnetic vibration noise during operation. This embodiment significantly reduces the back-EMF harmonic content and cogging torque by optimizing the motor rotor structure without reducing the back-EMF effective value.

[0049] In addition, the existing motor core and winding will generate additional losses under the action of harmonic currents. These losses will act as a heat source on the motor itself, causing its temperature to rise, and then affect the internal materials and electromagnetic performance parameters of the motor, causing its efficiency to decrease, thereby reducing its control performance. However, the magnetic pole 20 of this embodiment adopts a multi-segment magnetic steel structure, which helps to reduce the eddy current loss of the magnetic steel, reduce the temperature rise of the permanent magnet 21, and thus improve the motor control performance.

[0050] In one embodiment of the present invention, the stator core 30 can be formed by stacking stator punching sheets to reduce iron loss of the stator core 30 and improve output torque and efficiency. The stator punching sheets can be made of silicon steel sheets to reduce costs.

[0051] It should be noted that the rotor core 10 can also be formed by stacking rotor punchings to reduce the iron loss of the rotor core 10 and improve the output torque and efficiency. The rotor punchings can be made of silicon steel sheets to reduce costs.

[0052] An embodiment of the present invention further provides a compressor, which includes a casing in which the permanent magnet motor provided by any of the above embodiments is installed.

[0053] It is understood that the compressor of this embodiment uses the permanent magnet motor of the above embodiment and has the beneficial effects of the above permanent magnet motor, which will not be described in detail here. The compressor can be an air conditioner compressor, a refrigerator compressor, etc.

[0054] An embodiment of the present invention further provides a household appliance, which includes the permanent magnet motor provided by any of the above embodiments.

[0055] It is understood that the household appliance of this embodiment uses the permanent magnet motor of the above embodiment and has the beneficial effects of the above permanent magnet motor, which will not be described in detail here. The household appliance can be an air conditioner, a refrigerator, a microwave oven, a fan, a vacuum cleaner, etc.

[0056] The embodiment of the present invention further provides a method for manufacturing a motor rotor, such as Figure 3As shown, the method includes the following steps: Step 100: forming a plurality of mounting components 11 arranged along the circumferential direction on the rotor core 10, each mounting component 11 including a plurality of magnetic steel slots 111 arranged in sequence, and the plurality of magnetic steel slots 111 are arranged according to a cosine function.

[0057] Step 200 : Arrange a plurality of magnetic poles 20 in a one-to-one correspondence on a plurality of mounting components 11 , wherein each magnetic pole 20 includes a plurality of permanent magnets 21 corresponding to a plurality of magnetic steel slots 111 .

[0058] The motor rotor manufacturing method provided by an embodiment of the present invention adopts a plurality of magnetic steel slots 111 arranged in sequence through the mounting component 11, and the plurality of magnetic steel slots 111 are arranged according to a cosine function, so that the plurality of permanent magnets 21 arranged in the plurality of magnetic steel slots 111 are arranged in a cosine function, so that the magnetic poles 20 are a multi-segment, cosine function arrangement structure, so that the air gap magnetic field distribution is closer to a sine wave, and it is possible to significantly reduce the back electromotive force harmonic content without reducing the effective value of the back electromotive force, thereby improving the motor performance.

[0059] In one embodiment of the present invention, in step 100, the multiple mounting components 11 on the rotor core 10 have the same structure, such as Figure 4 As shown, the arrangement steps of any one of the mounting components 11 may include the following steps: Step 110 , determine the number of magnetic steel slots 111 .

[0060] Step 120: Determine multiple different function points based on the cosine function.

[0061] Step 130 : Determine the direction and size of each magnetic steel slot 111 based on multiple function points.

[0062] Step 140 : Based on the directions and sizes of the magnetic steel slots 111 , a mounting component 11 is formed on the rotor core 10 .

[0063] It can be understood that the number of magnetic steel slots 111 of the mounting component 11 is determined; based on the cosine function, multiple discrete function points are generated on the rotor core 10, and the direction and size of each magnetic steel slot 111 are determined based on the function points, so that based on the direction and size of each magnetic steel slot 111, multiple magnetic steel slots 111 arranged in sequence and according to the cosine function are constructed on the rotor core 10 through machining or lamination forming technology, thereby forming a mounting component 11 on the rotor core 10.

[0064] It should be noted that the magnetic steel slot 111 is designed in the form of a cosine function. The position and direction of the magnetic steel slot 111 are determined by taking points in the cosine function. Under the condition of the same amount of magnetic steel, the effective value of the motor back electromotive force is increased, the harmonic content is reduced, and the torque fluctuation is reduced, thereby further optimizing the vibration and noise performance of the motor.

[0065] It should be noted that the multiple mounting components 11 on the rotor core 10 adopt the same structural design, that is, the geometric shape, dimensional parameters, and material properties of each mounting component 11 are consistent. This standardized design allows that during the processing process, only the detailed structure of one mounting component 11 needs to be determined, and the position and orientation of the remaining mounting components 11 can be quickly determined based on its layout pattern on the rotor core 10. For example, in a permanent magnet synchronous motor, if the motor rotor adopts an 8-pole design, the mechanical angular spacing between adjacent mounting components 11 is 45°, and the spatial positioning and processing of all mounting components 11 can be completed through rotational copying or mirroring operations.

[0066] Optional, such as Figure 5 As shown, step 120 may include the following steps: Step 121 : construct a coordinate system, wherein the d-axis is used as the vertical axis and the horizontal axis is a direction perpendicular to the d-axis and passing through the axis of the rotor core 10 .

[0067] Step 122: Based on the cosine function and the coordinate system, determine multiple function points with different horizontal coordinates, and the maximum horizontal coordinate of the function point is , satisfy: , R represents the radius of the rotor core, and P represents the number of magnetic poles.

[0068] It can be understood that multiple processing positions arranged circumferentially are determined on the end face of the rotor core, and the number and position of the processing positions are determined based on the number and position of the mounting components; for example, if the rotor core has eight mounting components arranged along the circumferential direction, eight processing positions corresponding to the eight mounting components are first designed on the end face of the rotor core.

[0069] Taking the machining of one of the mounting components 11 as an example, a coordinate system is constructed. The line connecting the center of the machining position and the axis of the rotor core 10 is used as the d-axis, the d-axis is used as the ordinate, and the abscissa is the direction perpendicular to the d-axis and passing through the axis of the rotor core 10. Based on the cosine function, multiple function points with different abscissas are generated on the rotor core 10. It should be noted that the center of the machining position is the center of the mounting component 11.

[0070] Among them, the maximum value of the horizontal coordinate of the function point is , satisfy: , R represents the radius of the rotor core, and P represents the number of magnetic poles.

[0071] Optional, such as Figure 6 As shown, step 130 may include the following steps: Step 131 : Based on the number of magnetic steel slots 111 , determine a corresponding target cosine point from a plurality of function points.

[0072] Step 132: Based on the target cosine point or the function points adjacent to each target cosine point, determine the direction of the magnetic steel slot 111 corresponding to each target cosine point.

[0073] Step 133 : Determine the size of each magnetic steel slot 111 based on the offset distance and the direction of the magnetic steel slot 111 .

[0074] It is understood that when designing the multiple magnetic steel slots 111 of the mounting component 11, first, based on the number of magnetic steel slots 111 in the mounting component 11, target cosine points are selected from multiple function points pre-generated based on the cosine function. The number of target cosine points can correspond to the number of magnetic steel slots 111, and the target cosine points correspond one-to-one with the center position or key contour points of the magnetic steel slots 111, ensuring that the magnetic field distribution conforms to the expected cosine law. Next, the tangent direction is calculated using the target cosine point itself or its adjacent function points (such as the two function points before and after), thereby determining the spatial orientation of each magnetic steel slot 111. This step ensures the geometrically coordinated optimization of the magnetic steel slot 111 design and the magnetic field waveform. Finally, based on the preset offset distance (such as the minimum gap between the permanent magnet 21 and the slot wall or the width of the permanent magnet 21) and the determined direction of the magnetic steel slot 111, the size of each magnetic steel slot 111 is determined, so that the multiple magnetic steel slots 111 of the mounting component 11 conform to the cosine distribution law, thereby achieving efficient design and performance improvement of the motor rotor magnetic circuit.

[0075] It should be noted that the width dimensions of the multiple magnetic steel slots 111 of the mounting component 11 are the same, and the length dimensions of the multiple magnetic steel slots 111 can be the same or different; correspondingly, the length dimensions of the multiple permanent magnets 21 of the magnetic pole 20 match the length dimensions of the multiple magnetic steel slots 111, and the width of the magnetic steel slot 111 is slightly larger than the width of the permanent magnet 21, so as to facilitate the assembly of the permanent magnet 21 in the corresponding magnetic steel slot 111.

[0076] In a specific embodiment of the present invention, based on the designed number of mounting components 11 (i.e., magnetic poles 20), for example, a plurality of magnetic poles 20 are evenly distributed circumferentially; a plurality of processing positions evenly distributed circumferentially are determined on the end surface of the rotor core 10, and forming one of the mounting components 11 specifically includes the following steps: S1. Determine the number of magnetic steel slots 111.

[0077] For example, the mounting component 11 is an axisymmetric structure, and one mounting component 11 includes five magnetic steel slots 111 arranged in sequence, specifically including a first magnetic steel slot 101, two second magnetic steel slots 102 and two third magnetic steel slots 103. The two second magnetic steel slots 102 are symmetrically arranged on both sides of the first magnetic steel slot 101, and the two third magnetic steel slots 103 are symmetrically arranged on both sides of the first magnetic steel slot 101. The second magnetic steel slot 102 is located between the first magnetic steel slot 101 and the third magnetic steel slot 103.

[0078] S2. Based on the cosine function, determine multiple different function points.

[0079] Specifically, a coordinate system is constructed, wherein the line between the center of the processing position and the axis of the rotor core 10 is used as the d-axis, the d-axis is used as the vertical axis, and the horizontal axis is the direction perpendicular to the d-axis and passing through the axis of the rotor core 10.

[0080] A third magnetic steel slot 103, a second magnetic steel slot 102, a first magnetic steel slot 101, another second magnetic steel slot 102 and another third magnetic steel slot 103 are arranged according to a cosine function. The cosine function is: It is understood that the mounting component 11 is an axisymmetric structure, with the first magnetic steel slot 101 serving as the reference slot, and the magnetic steel slots 111 on both sides thereof being arranged in a mirror-symmetrical manner. The two second magnetic steel slots 102 and the two third magnetic steel slots 103 are symmetrically distributed with respect to the first magnetic steel slot 101. The position and geometric parameters of the first magnetic steel slot 101 can be determined first, and then the first side (e.g., Figure 2 The second magnetic steel slot 102 and the third magnetic steel slot 103 are arranged on the right side of the figure, and based on the principle of symmetry, on the second side (such as Figure 2 The left side of the figure (in the figure) is mirrored to generate the corresponding second magnetic steel slot 102 and third magnetic steel slot 103; based on this, multiple function points can be determined on one side of the vertical axis. It should be noted that the mounting component 11 adopts an axisymmetric structure, which not only simplifies the design process but also ensures the balance of the motor rotor magnetic circuit, reducing torque pulsation or vibration noise caused by asymmetry.

[0081] In this embodiment, five function points on the cosine function are determined on the right side of the vertical axis. The five function points are recorded as A, B, C, D, and E with increasing horizontal coordinates. The horizontal coordinates of the five function points are 2.5 mm, 4.5 mm, 6.5 mm, 8 mm, and 9.5 mm, respectively. The vertical coordinates of the five function points are f(2.5), f(4.5), f(6.5), f(8), and f(9.5), respectively.

[0082] S3. Based on multiple function points, determine the direction and size of each magnetic steel slot.

[0083] Based on function point A, determine the discrete point F on the ordinate axis corresponding to function point A. The ordinate of discrete point F is equal to the ordinate of function point A, and the abscissa of discrete point F is 0.

[0084] Connect the discrete point F and the function point A to get a line segment , is the direction of the first magnetic steel slot, toward the line segment The two sides are offset by a distance L, forming a first magnetic steel slot with a width of 2L. The two sides of the line segment here are perpendicular to the line segment and parallel to the end face of the rotor core. In this embodiment, L is set to 0.89mm, forming a first magnetic steel slot with a width of 1.78mm.

[0085] Connect function point A and function point C to get a line segment , The direction of the second magnetic steel slot is parallel to the function point B. straight line , to the straight line The two sides are offset by a distance L to form a second magnetic steel slot with a width of 2L.

[0086] Connect function point C and function point E to get a line segment , The direction of the third magnetic steel slot is parallel to the function point D. straight line , to the straight line The two sides are offset by a distance L to form a third magnetic steel slot with a width of 2L.

[0087] Based on the principle of symmetry, the corresponding second magnetic steel slot and third magnetic steel slot are determined on the other side of the vertical coordinate axis through mirror replication.

[0088] It should be noted that, in other embodiments, the formation of the first magnetic steel slot can also adopt the formation principle of the third magnetic steel slot, that is, the first magnetic steel slot is formed by three function points; of course, the formation of the first magnetic steel slot can also be formed by two function points arranged relatively along the horizontal axis direction, and the direction of the first magnetic steel slot is determined by the line connecting the two function points, and a distance L is offset on both sides of the line to form a first magnetic steel slot with a width of 2L.

[0089] It should be noted that, in each mounting component, the number of target cosine points corresponds to the designed number of magnetic steel slots, and the target cosine point serves as the center point of the magnetic steel slot; when the number of magnetic steel slots is an odd number, the magnetic steel slot located in the middle can be horizontal, and the positions of the remaining magnetic steel slots are determined by multiple function points. The direction of each section of the magnetic steel slot can be determined by the direction of the line connecting the function points on both sides of the target cosine point; when the number of magnetic steel slots is an even number, the direction of each section of the magnetic steel slot is determined by the direction of the line connecting the function points on both sides of the target cosine point.

[0090] S4. Based on the direction and size of each magnetic steel slot, a mounting component is formed on the rotor core.

[0091] It should be noted that, based on the structure of the above-mentioned one mounting component 11, multiple mounting components 11 arranged along the circumferential direction are formed on the rotor core 10, and multiple magnetic poles 20 are arranged one-to-one correspondingly on the multiple mounting components 11, thereby completing the manufacture of the motor rotor.

[0092] In a specific embodiment of the present invention, the method for manufacturing the motor rotor of this embodiment is verified, and the back electromotive force of a motor including any motor rotor of this embodiment and an existing motor is measured.

[0093] like Figure 7 and Figure 8 As shown, the vertical axis represents the back EMF voltage, in V (volts), ranging from -60V to +60V; the horizontal axis represents time, in seconds (seconds). Comparing the back EMF data, it can be seen that this embodiment achieves an RMS back EMF of 42.35 while maintaining a THD of 1.4%. Compared to existing motors, this improves the back EMF RMS by 4.8% while reducing the harmonic content by 4.7%. Consequently, the motor rotor of this embodiment achieves a higher RMS back EMF value, reduces copper loss in the motor, and reduces coil heating. Furthermore, the lower harmonic content reduces iron loss in the rotor core, reducing core heating.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A motor rotor, characterized in that: include: A rotor core having a plurality of mounting components arranged along a circumferential direction, each mounting component including a plurality of magnetic steel slots arranged in sequence, wherein the plurality of magnetic steel slots are arranged according to a cosine function; A plurality of magnetic poles are arranged in one-to-one correspondence with the plurality of mounting components, and each of the magnetic poles includes a plurality of permanent magnets in one-to-one correspondence with the plurality of magnetic steel slots.

2. The motor rotor according to claim 1, characterized in that: The cosine function is ; Wherein, a represents the first coefficient, b represents the second coefficient, and c represents a constant.

3. The motor rotor according to claim 2, characterized in that: satisfy: ; and / or, satisfy: ; and / or, and satisfy: ; Where R is the radius of the rotor core and P is the number of magnetic poles.

4. The motor rotor according to claim 1, characterized in that: A line connecting the center of the mounting component and the axis of the rotor core forms a d-axis, and the mounting component is an axisymmetric structure with the d-axis as a symmetry axis.

5. A permanent magnet motor, characterized in that: include: The motor stator comprises a stator core and a stator winding arranged on the stator core; The motor rotor according to any one of claims 1 to 4, wherein the stator core and the rotor core cooperate with each other.

6. A compressor, characterized in that: include: The permanent magnet motor according to claim 5.

7. A method for manufacturing a motor rotor, characterized in that: include: A plurality of mounting components are formed on the rotor core and arranged along the circumferential direction, each of the mounting components includes a plurality of magnetic steel slots arranged in sequence, and the plurality of magnetic steel slots are arranged according to a cosine function; A plurality of magnetic poles are arranged on the plurality of mounting components in a one-to-one correspondence, and each of the magnetic poles includes a plurality of permanent magnets corresponding to the plurality of magnetic steel slots in a one-to-one correspondence.

8. The method for manufacturing a motor rotor according to claim 7, wherein: The step of arranging any of the plurality of mounting components arranged circumferentially on the rotor core comprises: Determine the number of magnetic steel slots; Based on the cosine function, determine multiple different function points; Based on the plurality of function points, determining the direction and size of each magnetic steel slot; Based on the directions and sizes of the magnetic steel slots, mounting components are formed on the rotor core.

9. The method for manufacturing a motor rotor according to claim 8, characterized in that: The method of determining a plurality of different function points based on the cosine function includes: Construct a coordinate system, wherein the d-axis is used as the vertical axis and the horizontal axis is perpendicular to the d-axis and passes through the axis of the rotor core; Based on the cosine function and the coordinate system, multiple function points with different horizontal coordinates are determined, and the maximum horizontal coordinate of the function point is , satisfy: , R represents the radius of the rotor core, and P represents the number of magnetic poles.

10. The method for manufacturing a motor rotor according to claim 8 or 9, characterized in that: Determining the direction and size of each magnetic steel slot based on the plurality of function points includes: Based on the number of magnetic steel slots, determining a corresponding target cosine point from a plurality of the function points; Determine the magnetic steel slot direction corresponding to each target cosine point based on the target cosine point or the function points adjacent to each target cosine point; The size of each magnetic steel slot is determined based on the offset distance and the direction of the magnetic steel slot.

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