Motor

Abstract

The invention discloses a motor. The motor comprises a stator; the rotor is arranged on the inner side of the stator, a plurality of irregular concave edges which are sunken towards the axis of the rotor are formed on the outer side of the rotor in the circumferential direction, every two adjacent irregular concave edges are connected through an arc edge, in the radial direction of the rotor, the distance between the arc edge and the inner circle of the stator is Q1, and the distance between the arc edge and the inner circle of the stator is Q2. The maximum distance between the irregular concave edge and the outer circle of the rotor is Q2, and Q2 is larger than 1.5 Q1 and smaller than 2.5 Q1. According to the motor, the outer contour of the rotor is designed to be of a structure in which the arc edge and the irregular concave edge are connected through a reasonable numerical relational expression, the arc edge constructs equal air gaps, and the irregular concave edge is sunken towards the axis of the rotor to construct unequal air gaps, so that the cogging torque amplitude of the motor is reduced, the pulsation coefficient of the output torque is reduced, and electromagnetic noise is effectively optimized; and the overall performance of the motor is better.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and particularly to a motor. Background Art

[0002] At present, permanent magnet motors have advantages such as a large torque inertia ratio and precise speed control, and are increasingly used in various industries such as air-conditioning compressors. Cogging torque is one of the unique problems of permanent magnet motors, which will cause fluctuations in the output torque of the motor, and further exacerbate the vibration and noise of the motor. How to effectively weaken the amplitude of the cogging torque without deteriorating the performance of the motor is a problem that needs to be considered and solved in the design and manufacture of high-performance permanent magnet motors. In traditional motors, changing the pole distribution is often used to weaken the magnetic field harmonics, thereby weakening the amplitude of the cogging torque to a certain extent. However, due to factors such as the size of the rotor, there are many limitations in improving the cogging torque problem in the traditional way, and it cannot well reduce the fluctuations in the output torque of the motor, and the optimization effect of electromagnetic noise is not ideal enough. Summary of the Invention

[0003] Provide a motor to solve the problems of large output torque fluctuations and large electromagnetic noise caused by a large amplitude of the cogging torque of the motor.

[0004] The present invention provides a motor, which includes: a stator; a rotor, disposed inside the stator, and a plurality of irregular concave edges that are recessed toward its axis are formed along the circumferential direction on the outer side of the rotor. Adjacent two of the irregular concave edges are connected by arc edges. In the radial direction of the rotor, the distance from the arc edge to the inner circle of the stator is Q1, and the maximum distance from the irregular concave edge to the outer circle of the rotor is Q2, where 1.5Q1 < Q2 < 2.5Q1.

[0005] In the motor provided in the embodiment of the present invention, the irregular concave edge includes a first straight edge and a second straight edge. One ends of the first straight edge and the second straight edge are respectively connected to one ends of two adjacent arc edges that are close to each other, and the other ends of the first straight edge and the second straight edge are inclined and connected toward the rotor axis. Among them, the length of the first straight edge is different from the length of the second straight edge.

[0006] In the motor provided in the embodiment of the present invention, the sum of the lengths of all the arc edges is L1, and the sum of the lengths of the first straight edges and the second straight edges of all the irregular concave edges is L2, where 0.5 ≤ L2 / L1 ≤ 0.8.

[0007] In the motor provided by the embodiment of the present invention, the arc edge includes a first arc edge and a second arc edge. The first arc edge and the second arc edge are alternately distributed in the circumferential direction of the rotor. The first straight edge and the second straight edge are respectively connected to the first arc edge and the second arc edge. Among them, the arc length of the first arc edge is different from the arc length of the second arc edge.

[0008] In the motor provided by the embodiment of the present invention, several stator teeth extending towards the rotor are provided along the circumference on the inner side of the stator. The central angle corresponding to the center of the rotor axis on both sides of the end of the stator tooth close to the rotor and away from each other in the circumferential direction of the rotor is θ, and the central angle corresponding to the center of the rotor axis of the first arc edge is β, where 0.7 ≤ θ / β ≤ 0.85.

[0009] In the motor provided by the embodiment of the present invention, several groups of uniformly distributed magnetic poles are provided along the circumference on the inner side of the rotor. The midpoint of the first arc edge is located on the center line of the magnetic pole, and the midpoint of the second arc edge is located on the demarcation line between two adjacent groups of the magnetic poles.

[0010] In the motor provided by the embodiment of the present invention, several magnetic flux concentrating grooves away from the rotor axis are provided along the circumference on the inner side of the rotor. The magnetic flux concentrating grooves are located between the center line of the magnetic pole and the demarcation line between two adjacent groups of the magnetic poles and are adjacent to the first arc edge and the first straight edge.

[0011] In the motor provided by the embodiment of the present invention, the cross-sectional area of the magnetic flux concentrating groove in the axial direction of the rotor gradually increases from the end close to the center line of the magnetic pole to the end close to the demarcation line between two adjacent groups of the magnetic poles.

[0012] In the motor provided by the embodiment of the present invention, several stator teeth extending towards the rotor are provided along the circumference on the inner side of the stator. The width of each stator tooth is W1. The minimum distance from the magnetic flux concentrating groove to the demarcation line between two adjacent groups of the magnetic poles is d1, and the maximum distance from the magnetic flux concentrating groove to the demarcation line between two adjacent groups of the magnetic poles is d2. Among them, 0.8W1 ≤ d1 ≤ 0.95W1, and 1.3W1 ≤ d2 ≤ 1.5W1.

[0013] In the motor provided by the embodiment of the present invention, the minimum distance from the groove wall on the side of the magnetic flux concentrating groove away from the rotor axis to the first arc edge is d3, where 0.4 mm < d3 < 0.7 mm.

[0014] In the motor provided by the embodiment of the present invention, the magnetic flux concentrating slot has a first slot edge, a second slot edge, a third slot edge, and a fourth slot edge that are sequentially connected. The first slot edge is adjacent to the first arc edge, the second slot edge is adjacent to the first straight edge, the third slot edge is spaced from the dividing line between two adjacent groups of the magnetic poles, the fourth slot edge is spaced from the second slot edge and away from the first straight edge. The lengths of the second slot edge, the third slot edge, and the fourth slot edge are T2, T3, and T4 respectively, and the length of the first straight edge is L3. Wherein, T2 < T4 < L3, and 0.5 mm < T3 < 0.7 mm.

[0015] In the motor provided by the embodiment of the present invention, each group of the magnetic poles includes a first permanent magnet, a second permanent magnet, and a third permanent magnet. The third permanent magnet extends in the tangential direction of the rotor, and the first permanent magnet and the second permanent magnet are respectively connected to two mutually distant ends of the third permanent magnet and extend towards the outer circle of the rotor.

[0016] The present invention provides a motor. The motor includes a stator and a rotor. The rotor is arranged inside the stator. A plurality of irregular concave edges that are recessed towards its axis are formed along the circumferential direction on the outer side of the rotor. Adjacent two of the irregular concave edges are connected by an arc edge. In the radial direction of the rotor, the distance from the arc edge to the inner circle of the stator is Q1, and the maximum distance from the irregular concave edge to the outer circle of the rotor is Q2. Wherein, 1.5Q1 < Q2 < 2.5Q1. The motor of the present application designs the outer contour of the rotor as a structure in which an arc edge and an irregular concave edge are connected. The arc edge constructs an equal air gap, and the irregular concave edge is designed to be recessed towards the axis of the rotor to construct an unequal air gap. By reasonably designing the distance from the arc edge to the inner circle of the stator and the maximum distance from the irregular concave edge to the outer circle of the rotor through a numerical relationship formula, the amplitude of the cogging torque of the motor is reduced, the output torque ripple coefficient becomes smaller, the electromagnetic noise is effectively optimized, and the overall performance of the motor is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is an axial view of the assembly of the stator and the rotor provided by the embodiment of the present invention;

[0019] Figure 2 It is Figure 1 the enlarged view of part A of

[0020] Figure 3Axial view of the rotor provided by the embodiment of the present invention;

[0021] Figure 4 Another axial view of the stator and rotor assembly provided by the embodiment of the present invention;

[0022] Figure 5 Is Figure 3 Enlarged view of part A;

[0023] Figure 6 Is Figure 3 Enlarged view of part B;

[0024] Figure 7 Schematic structural diagram of the magnetic beam slot provided by the embodiment of the present invention.

[0025] In the figure, each reference numeral is as follows:

[0026] 1, stator; 11, stator teeth; 101, inner circle; 2, rotor; 201, outer circle; 3, irregular concave edge; 31, first straight edge; 32, second straight edge; 4, arc edge; 41, first arc edge; 42, second arc edge; 5, magnetic pole; 51, first permanent magnet; 52, second permanent magnet; 53, third permanent magnet; 6, magnetic beam slot; 61, first slot edge; 62, second slot edge; 63, third slot edge; 64, fourth slot edge. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] The directional terms mentioned in the present invention, such as "upper", "lower", "front", "rear", "left", "right", "inner", "outer", "side", etc., are only references to the directions in the attached drawings. Therefore, the directional terms used are for explaining and understanding the present invention, rather than for limiting the present invention. In addition, in the drawings, structures that are similar or the same are denoted by the same reference numerals.

[0029] To facilitate the understanding of the present invention, first, the motor provided by the embodiment of the present invention will be described. Refer to Figure 1 And Figure 2, an embodiment of the present invention provides a motor, which includes a stator 1 and a rotor 2; the rotor 2 is arranged inside the stator 1, and a plurality of irregular concave edges 3 that are recessed towards its axis are formed along the circumferential direction on the outer side of the rotor 2. Adjacent two of the irregular concave edges 3 are connected by an arc edge 4. In the radial direction of the rotor 2, the distance from the arc edge 4 to the inner circle 101 of the stator 1 is Q1, and the maximum distance from the irregular concave edge 3 to the outer circle 201 of the rotor 2 is Q2, where 1.5Q1 < Q2 < 2.5Q1.

[0030] In a traditional motor, the air gap between the stator and the rotor is mostly a regular circular ring-shaped air gap. During the operation of the motor, the amplitude of the cogging torque is relatively large, resulting in a relatively large torque ripple coefficient of the motor, large fluctuations in the output torque of the motor, and obvious electromagnetic noise. Therefore, an embodiment of the present invention proposes a motor to solve the problems of large output torque fluctuations and large electromagnetic noise caused by a large amplitude of the cogging torque of the motor. The specific idea is as follows:

[0031] Such as Figure 1 , Figure 2As shown in the figure, the motor of this embodiment includes a stator 1 and a rotor 2. In addition, the motor also includes a housing and its related components. The stator 1 and the rotor 2 are the basic components of the motor. The stator 1 is mainly equipped with windings. The rotor 2 is installed inside the stator 1 and is coaxial with the stator 1. The rotor 2 is mainly composed of components such as an iron core, a rotating shaft, and a permanent magnet. The operating principle of the motor is that the stator 1 is responsible for generating a rotating magnetic field by energizing the windings, and the rotor 2 is responsible for generating a constant magnetic field to interact with the magnetic field of the stator 1 to generate torque, thereby enabling the motor to operate and output power. In this embodiment, the outer contour of the rotor 2 is an incomplete circle. Along the circumferential direction of the rotor 2, several irregular concave edges 3 that are recessed towards its axis are formed on the outer side. From the axial direction of the rotor 2, these irregular concave edges 3 are part of the outer contour of the rotor 2. The irregular concave edges 3 are recessed towards the axis of the rotor 2. In fact, they are formed by opening grooves on the outer side of the rotor 2. The irregular concave edges 3 are the contour lines of the grooves on the outer side of the rotor 2. The shape of the irregular concave edges 3 is usually irregular. It can be composed of multiple straight lines connected, or composed of curves, or composed of a connection of straight lines and curves, and no restrictions are made here. The adjacent two irregular concave edges 3 are connected by an arc edge 4. The arc edge 4 is a standard circular arc and coincides with the outer circle 201 of the rotor 2. Its quantity is the same as that of the irregular concave edges 3. The arc edge 4 and the irregular concave edges 3 are alternately connected to form the entire outer contour of the rotor 2. The area between the arc edge 4 and the inner circle 101 of the stator 1 is an equal air gap area, while the space between the irregular concave edges 3 and the inner circle 101 of the stator 1 is an unequal air gap area. The equal air gap area means that in the circumferential direction of the rotor 2, the length of the air gap remains uniformly unchanged, while the unequal air gap means that in the circumferential direction of the rotor 2, the length of the air gap is variable. Here, the length of the air gap refers to the distance from the radial outer wall of the rotor 2 to the inner circle 101 of the stator 1 in the radial direction of the rotor 2. The range spanned by both ends of the arc edge 4 corresponds to the air gap length being equal everywhere, while the range spanned by both ends of the irregular concave edges 3 corresponds to the air gap length being variable everywhere. In the radial direction of the rotor 2, the distance from the arc edge 4 to the inner circle 101 of the stator 1 is represented by Q1. Q1 is the length of the equal air gap. The maximum distance from the irregular concave edge 3 to the outer circle 201 of the rotor 2 is represented by Q2. In the design, 1.5Q1 < Q2 < 2.5Q1, that is, the maximum distance from the irregular concave edge 3 to the outer circle 201 of the rotor 2 is designed within the range of 1.5 to 2.5 times the distance from the arc edge 4 to the inner circle 101 of the stator 1. Within this range, the ratio of the length of the equal air gap to the length of the equal air gap reaches a better value. Through actual measurement, when the arc edge 4 and the irregular concave edges 3 on the outer side of the rotor 2 are designed according to the relationship 1.5Q1 < Q2 < 2.5Q1, the amplitude of the cogging torque during the operation of the motor is at a relatively low level, the torque ripple coefficient of the motor is small, and the electromagnetic noise is reduced.

[0032] In this embodiment, the outer contour of the rotor of the motor is designed as a structure in which an arc edge is connected to an irregular concave edge. The arc edge constructs an equal air gap, and the irregular concave edge is designed to be recessed towards the axis of the rotor to construct an unequal air gap. By designing the distance from the arc edge to the inner circle of the stator and the maximum distance from the irregular concave edge to the outer circle of the rotor through a reasonable numerical relationship, the amplitude of the cogging torque of the motor is reduced, the output torque ripple coefficient becomes smaller, the electromagnetic noise is effectively optimized, and the overall performance of the motor is better.

[0033] In one embodiment, referring to Figure 2 and Figure 3 , the irregular concave edge 3 includes a first straight edge 31 and a second straight edge 32. One end of each of the first straight edge 31 and the second straight edge 32 is connected to one end of two adjacent arc edges 4 that are close to each other. The other ends of the first straight edge 31 and the second straight edge 32 are inclined and connected towards the axis of the rotor 2. Among them, the length of the first straight edge 31 is different from the length of the second straight edge 32. In a specific implementation, the irregular concave edge 3 is formed by connecting two straight edges. One of them is the first straight edge 31, and the other is the second straight edge 32. In the irregular concave edge 3 sandwiched between two adjacent arc edges 4, one end of each of the first straight edge 31 and the second straight edge 32 that make it up is connected to one end of two adjacent arc edges 4 that are close to each other, and the other ends of the first straight edge 31 and the second straight edge 32 are inclined and connected towards the axis of the rotor 2. In terms of design, the lengths of the first straight edge 31 and the second straight edge 32 are different. Specifically, the first straight edge 31 can be longer than the second straight edge 32, or the first straight edge 31 can be shorter than the second straight edge 32. In this embodiment, the case where the first straight edge 31 is longer than the second straight edge 32 is taken as an example. Since the lengths of the first straight edge 31 and the second straight edge 32 are designed differently, within the range spanned by the first straight edge 31 and the second straight edge 32 in the circumferential direction of the rotor 2, the length of the unequal air gap shows two different linear changes. Within the range spanned by the longer one of the first straight edge 31 and the second straight edge 32, that is, within the range spanned by the first straight edge 31, the change in the unequal air gap is smaller, while within the range spanned by the shorter one of the two, that is, within the range spanned by the second straight edge 32, the change in the unequal air gap is larger. Through the large and small changes in the unequal air gap, the amplitude of the adjusted cogging torque can be at a lower level, reducing the torque ripple coefficient of the motor and optimizing the electromagnetic noise of the motor.

[0034] Further, the sum of the lengths of all the arc edges 4 is L1, and the sum of the lengths of the first straight edges 31 and the second straight edges 32 of all the irregular concave edges 3 is L2, where 0.5 ≤ L2 / L1 ≤ 0.8. In a specific implementation, the range of the equal air gaps is determined by the number and length of the arc edges 4, and the range of the unequal air gaps is determined by the number and length of the irregular concave edges 3. Since the arc edges 4 and the irregular concave edges 3 are alternately connected and have the same number, the ranges of the equal air gaps and the unequal air gaps are mainly determined by the lengths of the arc edges 4 and the irregular concave edges 3. Let L1 represent the sum of the lengths of all the arc edges 4, and the length of the arc edge 4 is taken as the arc length. Let L2 represent the sum of the lengths of the first straight edges 31 and the second straight edges 32 of all the irregular concave edges 3. In the design, 0.5 ≤ L2 / L1 ≤ 0.8, that is, the ratio of the sum of the lengths of all the arc edges 4 to the sum of the lengths of the first straight edges 31 and the second straight edges 32 of all the irregular concave edges 3 is in the range of 0.5 to 0.8. That is, the sum of the lengths of the first straight edges 31 and the second straight edges 32 of all the irregular concave edges 3 can be at most 0.8 times the sum of the lengths of all the arc edges 4 and at least 0.5 times the sum of the lengths of all the arc edges 4. By designing the lengths of the arc edges 4 and the first straight edges 31 and the second straight edges 32 of the irregular concave edges 3 according to the relationship 0.5 ≤ L2 / L1 ≤ 0.8, the ranges of the equal air gaps and the unequal air gaps reach a better ratio, which can reduce the distortion rate of the air gap magnetic field, improve the sinusoidality of the back electromotive force waveform, reduce the amplitude of the cogging torque of the motor and the torque ripple of the motor, and improve the NVH (Noise, Vibration, Harshness) performance of the motor.

[0035] In one embodiment, referring to Figure 2 and Figure 3, the arc edge 4 includes a first arc edge 41 and a second arc edge 42. The first arc edge 41 and the second arc edge 42 are alternately distributed in the circumferential direction of the rotor 2. The first straight edge 31 and the second straight edge 32 are respectively connected to the first arc edge 41 and the second arc edge 42. Among them, the arc length of the first arc edge 41 is different from the arc length of the second arc edge 42. In a specific implementation, the arc edge 4 is composed of the first arc edge 41 and the second arc edge 42. The radian of the first arc edge 41 and the second arc edge 42 is the same, but the arc length is different. The first arc edge 41 and the second arc edge 42 are alternately distributed in the circumferential direction of the rotor 2. The two adjacent irregular concave edges 3 are connected by the first arc edge 41 or the second arc edge 42. The first straight edge 31 and the second straight edge 32 that constitute each irregular concave edge 3 are respectively connected to the first arc edge 41 and the second arc edge 42. The arc lengths of the first arc edge 41 and the second arc edge 42 are different. Specifically, the arc length of the first arc edge 41 may be greater than the arc length of the second arc edge 42, or the arc length of the first arc edge 41 may be less than the arc length of the second arc edge 42. In this embodiment, an example is given in which the radian of the first arc edge 41 is designed to be greater than the radian of the second arc edge 42. Since the arc lengths of the first arc edge 41 and the second arc edge 42 are different, the equal air-gap range corresponding to the first arc edge 41 is different from the equal air-gap range corresponding to the second arc edge 42. The equal air-gap corresponding to the first arc edge 41 and the equal air-gap corresponding to the second arc edge 42 are connected by the unequal air-gap corresponding to the irregular concave edge 3. The equal air-gap in a large and a small range is connected to both ends of the unequal air-gap. By the fact that the equal air-gap range corresponding to the first arc edge 41 is different from the equal air-gap range corresponding to the second arc edge 42, in the circumferential direction of the rotor 2, the equal air-gap shows an alternating distribution in a large and a small range. Reasonably optimizing the distribution ratio of the equal air-gap can better reduce the amplitude of the cogging torque, reduce the torque ripple coefficient of the motor, and optimize the electromagnetic noise of the motor.

[0036] In one embodiment, referring to Figure 4, a plurality of stator teeth 1 extending towards the rotor 2 are provided along the circumference on the inner side of the stator 1. The central angle corresponding to the rotor 2 axis of the two sides of the end of the stator tooth 1 close to the rotor 2 that are away from each other in the circumferential direction of the rotor 2 is θ, and the central angle corresponding to the rotor 2 axis of the first arc edge 41 is β, where 0.7 ≤ θ / β ≤ 0.85. In a specific implementation, a plurality of stator teeth 1 are provided on the inner side of the stator 1. The stator teeth 1 extend towards the rotor 2 for a certain length, and a certain distance is spaced between adjacent two stator teeth 1 to form a stator slot 1. The stator teeth 1 are used to install the windings of the stator 1. The inner circle 101 of the stator 1 is the connection locus of the sides of all the stator teeth 1 facing the rotor 2. The end of the stator tooth 1 close to the rotor 2 is the widest, that is, the tooth part of the stator tooth 1 is the widest. Use θ to represent the central angle corresponding to the rotor 2 axis of the two sides of the end of the stator tooth 1 close to the rotor 2 that are away from each other in the circumferential direction of the rotor 2, that is, the central angle corresponding to the rotor 2 axis of the tooth part of the stator tooth 1 is θ. Use β to represent the central angle corresponding to the rotor 2 axis of the first arc edge 41. In the design, 0.7 ≤ θ / β ≤ 0.85, that is, the ratio of the central angle corresponding to the rotor 2 axis of the two sides of the end of the stator tooth 1 close to the rotor 2 that are away from each other in the circumferential direction of the rotor 2 to the central angle corresponding to the rotor 2 axis of the first arc edge 41 is in the range of 0.7 to 0.85. That is, the maximum central angle corresponding to the rotor 2 axis of the two sides of the end of the stator tooth 1 close to the rotor 2 that are away from each other in the circumferential direction of the rotor 2 can be 0.85 times the central angle corresponding to the rotor 2 axis of the first arc edge 41, and the minimum can be 0.5 times the central angle corresponding to the rotor 2 axis of the first arc edge 41. Through actual measurement, by designing the stator tooth 1 and the first arc edge 41 through the relationship 0.7 ≤ θ / β ≤ 0.85, most of the magnetic flux in each magnetic pole unit of the rotor 2 can flow to the tooth part of the stator tooth 1, so as to generate an effective torque. At the same time, the magnetic flux density of the boot part of the stator tooth 1 can be reduced, the iron loss of the stator 1 can be reduced, and the energy efficiency of the motor can be improved.

[0037] In one embodiment, referring to Figure 1 and Figure 3 , a plurality of groups of uniformly distributed magnetic poles 5 are provided along the circumference on the inner side of the rotor 2. The midpoint of the first arc edge 41 is located on the center line of the magnetic pole 5, and the midpoint of the second arc edge 42 is located on the demarcation line between adjacent two groups of magnetic poles 5. In a specific implementation, a plurality of groups of magnetic poles 5 are provided on the inner side of the rotor 2. All the magnetic poles 5 are uniformly distributed along the circumference of the rotor 2. Each group of magnetic poles 5 is composed of at least one permanent magnet (magnet steel). The magnetic poles 5 generate a constant magnetic field for the rotor 2, so as to cooperate with the rotating magnetic field generated by the stator 1 through the energization of the windings to generate torque. In the design, the midpoint of each first arc edge 41 is located on the center line of each group of magnetic poles 5. The center line of the magnetic pole 5 is usually used as the d-axis of the rotor 2, as Figure 3As shown. The midpoint of each second arc edge 42 is located on the demarcation line between adjacent two sets of magnetic poles 5, and the demarcation line between adjacent two sets of magnetic poles 5 is usually used as the q-axis of the rotor 2, such as Figure 3 As shown. By designing the midpoint of the first arc edge 41 on the center line of the magnetic pole 5 and the midpoint of the second arc edge 42 on the demarcation line between adjacent two sets of magnetic poles 5, the equal air-gap region is bisected by the d-axis and q-axis of the rotor 2, promoting the air-gap magnetic field to approach a sine waveform, thereby improving the performance of the motor.

[0038] Furthermore, referring to Figure 3 , a plurality of magnetic flux concentrating grooves 6 far from the axis of the rotor 2 are provided on the inner side of the rotor 2 along the circumferential direction. The magnetic flux concentrating grooves 6 are located between the center line of the magnetic pole 5 and the demarcation line between adjacent two sets of magnetic poles 5 and are adjacent to the first arc edge 41 and the first straight edge 31. In a specific implementation, a plurality of magnetic flux concentrating grooves 6 are arranged along the circumferential direction on the inner side of the rotor 2. The magnetic flux concentrating grooves 6 are far from the axis of the rotor 2 in the radial direction of the rotor 2 and close to the outer circle 201 of the rotor 2. Both ends of the magnetic flux concentrating grooves 6 penetrate through both sides in the axial direction of the rotor 2. Each magnetic flux concentrating groove 6 is located between the center line of each set of magnetic poles 5 and the demarcation line between adjacent two sets of magnetic poles 5, that is, there is a magnetic flux concentrating groove 6 between the center line of each set of magnetic poles 5 and the demarcation line between adjacent two sets of magnetic poles 5, and the magnetic flux concentrating grooves 6 are adjacent to the first arc edge 41 and the first straight edge 31, specifically at the junction between the first arc edge 41 and the first straight edge 31. The shape profile of the magnetic flux concentrating grooves 6 is arbitrary and can be designed as a circle, a polygon or an irregular shape, which is not limited herein. Since the magnetic flux concentrating grooves 6 are located between the center line of the magnetic pole 5 and the demarcation line between adjacent two sets of magnetic poles 5, the magnetic field can be effectively regulated through the magnetic flux concentrating grooves 6, the magnetic circuit can be optimized, the sinusoidalization of the air-gap magnetic field can be promoted, and further the torque ripple can be effectively reduced.

[0039] Even further, referring to Figure 3 and Figure 5 , the cross-sectional area of the magnetic flux concentrating groove 6 in the axial direction of the rotor 2 gradually increases from the end close to the center line of the magnetic pole 5 to the end close to the demarcation line between adjacent two sets of magnetic poles 5. In a specific implementation, the shape of the magnetic flux concentrating groove 6 is designed to be wide at one end and narrow at the other end. The end of the magnetic flux concentrating groove 6 close to the center line of the magnetic pole 5 is wider, and the end close to the demarcation line between adjacent two sets of magnetic poles 5 is narrower. Thus, the cross-sectional area of the magnetic flux concentrating groove 6 in the axial direction of the rotor 2 gradually increases from the end close to the center line of the magnetic pole 5 to the end close to the demarcation line between adjacent two sets of magnetic poles 5. Through the shape design of the magnetic flux concentrating groove 6 with one wide end and one narrow end, it can ensure that the magnetic field flowing through it changes evenly, showing a sine waveform change with the center of the magnetic pole 5 as the peak, restricting the change trend of the magnetic flux in each set of magnetic poles 5. The magnetic flux gradually increases from both ends to the middle of the first arc edge 41, showing a sine waveform change with the center of the magnetic pole 5 as the peak, thereby weakening the torque ripple of the motor.

[0040] In one embodiment, referring to Figure 4 and Figure 5 , a plurality of stator teeth 1 extending toward the rotor 2 are provided along the circumference on the inner side of the stator 1. The width of each stator tooth 1 is W1. The minimum distance from the magnetic flux concentrating groove 6 to the demarcation line between two adjacent sets of magnetic poles 5 is d1, and the maximum distance from the magnetic flux concentrating groove 6 to the demarcation line between two adjacent sets of magnetic poles 5 is d2. Wherein, 0.8W1 ≤ d1 ≤ 0.95W1, 1.3W1 ≤ d2 ≤ 1.5W1. In a specific implementation, a plurality of stator teeth 1 are arranged on the inner side of the stator 1. The stator teeth 1 extend toward the rotor 2 by a certain length. A certain distance is spaced between two adjacent stator teeth 1 to form a stator slot 1. The stator teeth 1 are used to install the windings of the stator 1. The end of the stator tooth 1 close to the rotor 2 is the widest, that is, the tooth part of the stator tooth 1 is the widest. The side of the stator tooth 1 away from the axis of the rotor 2 is the yoke part. The width of the stator tooth 1 here is the width of the part between the tooth part and the yoke part of the stator tooth 1. Use W1 to represent the width of the stator tooth 1, use d1 to represent the minimum distance from the magnetic flux concentrating groove 6 to the demarcation line between two adjacent sets of magnetic poles 5, use d2 to represent the maximum distance from the magnetic flux concentrating groove 6 to the demarcation line between two adjacent sets of magnetic poles 5. In the design, 0.8W1 ≤ d1 ≤ 0.95W1, 1.3W1 ≤ d2 ≤ 1.5W1, that is, the minimum distance from the magnetic flux concentrating groove 6 to the demarcation line between two adjacent sets of magnetic poles 5 is designed to be 0.8 to 0.95 times the width of the stator tooth 1, and the maximum distance from the magnetic flux concentrating groove 6 to the demarcation line between two adjacent sets of magnetic poles 5 is designed to be 1.3 to 1.5 times the width of the stator tooth 1. Through actual measurement, according to the relationship 0.8W1 ≤ d1 ≤ 0.95W1, the minimum distance from the magnetic flux concentrating groove 6 to the demarcation line between two adjacent sets of magnetic poles 5 is designed, and according to the relationship 1.3W1 ≤ d2 ≤ 1.5W1, the maximum distance from the magnetic flux concentrating groove 6 to the demarcation line between two adjacent sets of magnetic poles 5 is designed. By matching the size design of the stator teeth 1, the magnetic flux changing in a sine wave shape with the center of the magnetic pole 5 as the peak can perfectly flow to the tooth part of the stator tooth 1, thereby weakening the torque ripple of the motor.

[0041] In one embodiment, referring to Figure 6, the minimum distance from the groove wall on the side of the magnetic beam groove 6 away from the axis of the rotor 2 to the first arc edge 41 is d3, where 0.4 mm < d3 < 0.7 mm. In a specific implementation, the magnetic beam groove 6 is arranged radially away from the axis of the rotor 2 and adjacent to the first arc edge 41 and the first straight edge 31. The groove wall on the side of the magnetic beam groove 6 away from the axis of the rotor 2 is adjacent to the first arc edge 41. In a specific application, the part between the magnetic beam groove 6 and the first arc edge 41 is the iron core part of the rotor 2. If this part is designed too narrow, it will affect the structural strength of the rotor 2, and if it is designed too wide, the effect of improving the magnetic circuit cannot be achieved. Therefore, it needs to be designed within a reasonable range. Let d3 represent the minimum distance from the groove wall on the side of the magnetic beam groove 6 away from the axis of the rotor 2 to the first arc edge 41. In the design, 0.4 mm < d3 < 0.7 mm, that is, the minimum distance from the groove wall on the side of the magnetic beam groove 6 away from the axis of the rotor 2 to the first arc edge 41 is designed in the range of 0.4 mm to 0.7 mm. In this way, magnetic leakage can be effectively reduced without affecting the structural strength of the rotor 2, which is beneficial to improving the noise of the motor and enhancing the cost performance of the motor.

[0042] In an embodiment, referring to Figure 6 and Figure 7 , the magnetic beam groove 6 has a first groove side 61, a second groove side 62, a third groove side 63, and a fourth groove side 64 connected in sequence. The first groove side 61 is adjacent to the first arc edge 41. The second groove side 62 is adjacent to the first straight edge 31. The third groove side 63 is spaced from the boundary line between two adjacent groups of the magnetic poles 5. The fourth groove side 64 is spaced from the second groove side 62 and away from the first straight edge 31. The lengths of the second groove side 62, the third groove side 63, and the fourth groove side 64 are T2, T3, and T4 respectively. The length of the first straight edge 31 is L3, where T2 < T4 < L3, 0.5 mm < T3 < 0.7 mm. In a specific implementation, the shape of the magnetic beam groove 6 is designed as a trapezoid or a trapezoid-like shape. The magnetic beam groove 6 has a first groove side 61, a second groove side 62, a third groove side 63, and a fourth groove side 64 connected in sequence, that is, the magnetic beam groove 6 is enclosed by four sides. The first groove side 61 is adjacent to the first arc edge 41. The second groove side 62 is adjacent to the first straight edge 31. The third groove side 63 is spaced from the boundary line between two adjacent groups of the magnetic poles 5. The fourth groove side 64 is spaced from the second groove side 62 and away from the first straight edge 31. As Figure 7As shown, the lengths of the second slot side 62, the third slot side 63, and the fourth slot side 64 are represented by T2, T3, and T4 respectively, and the length of the first straight side 31 is represented by L3. In the design, T2 < T4 < L3 and 0.5 mm < T3 < 0.7 mm, that is, the length of the second slot side 62 is less than the length of the fourth slot side 64, and the length of the fourth slot side 64 is less than the length of the first straight side 31. Thus, the shape of the magnetic flux concentrating slot 6 is trapezoidal. The second slot side 62 and the fourth slot side 64 are equivalent to the upper base and the lower base of the trapezoidal magnetic flux concentrating slot 6, and the third slot side 63 is equivalent to the height of the trapezoidal magnetic flux concentrating slot 6. The second slot side 62 and the fourth slot side 64 are both corresponding to the first straight side 31. The length of the third slot side 63 is designed in the range of 0.5 mm to 0.7 mm. Through actual measurement, by setting the trapezoidal magnetic flux slot with the above dimension relationship, the magnetic field can be effectively regulated to promote the sinusoidization of the air-gap magnetic field, thereby reducing the torque ripple.

[0043] In one embodiment, referring to Figure 1 , Figure 3 and Figure 4 , each group of the magnetic poles 5 includes a first permanent magnet 51, a second permanent magnet 52, and a third permanent magnet 53. The third permanent magnet 53 extends in the tangential direction of the rotor 2, and the first permanent magnet 51 and the second permanent magnet 52 are respectively connected to two mutually remote ends of the third permanent magnet 53 and extend towards the outer circle 201 of the rotor 2. In a specific implementation, each group of the magnetic poles 5 is composed of the first permanent magnet 51, the second permanent magnet 52, and the third permanent magnet 53. The first permanent magnet 51, the second permanent magnet 52, and the third permanent magnet 53 are usually magnet steels after magnetization. The third permanent magnet 53 extends in the tangential direction of the rotor 2, while the first permanent magnet 51 and the second permanent magnet 52 are respectively connected to two mutually remote ends of the third permanent magnet 53, and both the first permanent magnet 51 and the second permanent magnet 52 extend towards the outer circle 201 of the rotor 2. Overall, the first permanent magnet 51, the second permanent magnet 52, and the third permanent magnet 53 form a "U"-shaped magnetic pole 5. The "U"-shaped magnetic pole 5 helps to concentrate the magnetic flux, improve the air-gap magnetic density, thereby enhancing the torque of the motor, and may also help to reduce the magnetic leakage and improve the efficiency.

[0044] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A motor, characterized in that, Comprising: A stator; A rotor, disposed inside the stator. A plurality of irregular concave edges that are recessed towards its axis are formed along the circumferential direction on the outer side of the rotor. Adjacent two of the irregular concave edges are connected by an arc edge. In the radial direction of the rotor, the distance from the arc edge to the inner circle of the stator is Q1, and the maximum distance from the irregular concave edge to the outer circle of the rotor is Q2, where 1.5Q1 < Q2 < 2.5Q1.

2. The motor according to claim 1, wherein The irregular concave edge includes a first straight edge and a second straight edge. One end of each of the first straight edge and the second straight edge is respectively connected to one end of two adjacent arc edges that are close to each other. The other ends of the first straight edge and the second straight edge are inclined and connected towards the rotor axis. Among them, the length of the first straight edge is different from the length of the second straight edge.

3. The motor according to claim 2, characterized in that The sum of the lengths of all the arc edges is L1, and the sum of the lengths of the first straight edges and the second straight edges of all the irregular concave edges is L2, where 0.5 ≤ L2 / L1 ≤ 0.

8.

4. The electric machine according to any one of claims 2-3, characterized in that, The arc edge includes a first arc edge and a second arc edge. The first arc edge and the second arc edge are alternately distributed in the circumferential direction of the rotor. The first straight edge and the second straight edge are respectively connected to the first arc edge and the second arc edge. Among them, the arc length of the first arc edge is different from the arc length of the second arc edge.

5. The motor according to claim 4, characterized in that, A plurality of stator teeth extending towards the rotor are provided along the circumferential direction on the inner side of the stator. The central angle corresponding to the rotor axis on both sides of the end of each stator tooth close to the rotor and away from each other in the circumferential direction of the rotor is θ, and the central angle corresponding to the rotor axis of the first arc edge is β, where 0.7 ≤ θ / β ≤ 0.

85.

6. The motor according to claim 4, wherein A plurality of groups of uniformly distributed magnetic poles are provided along the circumferential direction on the inner side of the rotor. The midpoint of the first arc edge is located on the center line of the magnetic pole, and the midpoint of the second arc edge is located on the demarcation line between two adjacent groups of magnetic poles.

7. The motor according to claim 6, characterized in that, A plurality of magnetic flux concentrating grooves away from the rotor axis are provided along the circumferential direction on the inner side of the rotor. The magnetic flux concentrating grooves are located between the center line of the magnetic pole and the demarcation line between two adjacent groups of magnetic poles and are adjacent to the first arc edge and the first straight edge.

8. The motor according to claim 7, characterized in that, The cross-sectional area of the magnetic flux concentrating groove in the axial direction of the rotor gradually increases from the end close to the center line of the magnetic pole to the end close to the demarcation line between two adjacent groups of magnetic poles.

9. The motor according to claim 7, characterized in that, A plurality of stator teeth extending towards the rotor are provided along the circumferential direction on the inner side of the stator. The width of each stator tooth is W1. The minimum distance from the magnetic flux concentrating groove to the demarcation line between two adjacent groups of magnetic poles is d1, and the maximum distance from the magnetic flux concentrating groove to the demarcation line between two adjacent groups of magnetic poles is d2, where 0.8W1 ≤ d1 ≤ 0.95W1, 1.3W1 ≤ d2 ≤ 1.5W1.

10. The motor according to claim 7, characterized in that, The minimum distance from the groove wall on the side of the magnetic flux concentrating groove away from the rotor axis to the first arc edge is d3, where 0.4 mm < d3 < 0.7 mm.

11. The motor according to claim 7, wherein, The magnetic slot includes a first slot edge, a second slot edge, a third slot edge and a fourth slot edge connected in sequence. The first slot edge is adjacent to the first arc edge, the second slot edge is adjacent to the first straight edge, the third slot edge is spaced from the dividing line between two adjacent sets of the magnetic poles, the fourth slot edge is spaced from the second slot edge and away from the first straight edge. The lengths of the second slot edge, the third slot edge and the fourth slot edge are T2, T3 and T4 respectively, and the length of the first straight edge is L3. Wherein, T2 < T4 < L3, and 0.5mm < T3 < 0.7mm.

12. The motor according to claim 6, characterized in that, Each set of the magnetic poles includes a first permanent magnet, a second permanent magnet and a third permanent magnet. The third permanent magnet extends in the tangential direction of the rotor, and the first permanent magnet and the second permanent magnet are respectively connected to two mutually remote ends of the third permanent magnet and extend towards the outer circle of the rotor.

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