Rotor magnetic ring and motor using same

Abstract

The utility model discloses a rotor magnetic ring and a motor using the same, and the rotor magnetic ring comprises a magnetic ring body which comprises a plurality of S-pole magnetic poles and N-pole magnetic poles which are uniformly arranged along the circumferential direction and are alternately arranged; the plurality of material jacking parts are uniformly arranged on one shaft side end of the magnetic ring body along the circumferential direction; the center of each jacking part is positioned in an adjacent region formed by the adjacent S-pole magnetic pole and N-pole magnetic pole; the central angle alpha corresponding to the adjacent area is equal to + / -(360 / 2N) * 0.2, N is the number of pairs of magnetic poles and is greater than or equal to 3, and the central angle corresponding to the adjacent area takes a boundary line of the adjacent S-pole magnetic pole and N-pole magnetic pole as an angular bisector and a zero line. According to the utility model, the requirements of injection molding and demolding of the rotor magnetic ring and the uniformity of the change of the magnetic field sensed by the Hall in the use process can be met.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technical field especially relates to a rotor magnetic ring and the motor of application thereof. BACKGROUND

[0002] Hall induction magnetic ring is mostly the same sex ferrite magnetic ring, and the ferrite magnetic ring has stable magnetism, clear magnetic pole, and provides stable magnetic pole signal for Hall induction element. As an important component of motor, Hall induction magnetic ring plays a very important role in the operation of motor system.

[0003] For the type of Hall induction magnetic ring, the injection molding magnetic ring is widely used in the prior art, which is processed by injection molding method. The injection molding method is to mix and granulate the powder of magnetic powder and resin, then inject the granulated material into an injection molding machine for heating and melting, so that it has good fluidity. In this state, the granulated material is injected into a metal mold with an oriented magnetic field in a molten state, and the required complex-shaped magnetic device is formed after cooling. At present, according to different types of magnetic powder, injection molding magnetic rings are generally divided into injection molding permanent ferrite magnetic ring, injection molding isotropic neodymium iron boron magnetic ring, injection molding anisotropic neodymium iron boron magnetic ring, injection molding SmFeN magnetic ring and injection molding composite magnetic ring, etc. Among them, the injection molding permanent ferrite magnetic ring has been widely used in the fields of printer magnetic roller, induction magnetic ring and micro motor rotor due to its advantages of high magnetic performance, low cost, oxidation resistance and high temperature resistance.

[0004] For this purpose, for the injection molding permanent ferrite magnetic ring, in the specific processing process, the ferrite is injected into the mold through the glue inlet, and the finished product is ejected by the ejector pin on the mold after molding. According to the above steps, the end part of the injection molding permanent ferrite magnetic ring matched with the mold ejector pin will form a material ejecting part, and the material ejecting part will have different depths, and most of the material ejecting part is arranged on the Hall induction surface of the magnetic ring. When the material ejecting part is arranged at the position corresponding to the strong magnetic field at the end of the magnetic pole, the deeper the depth of the material ejecting part, the more disordered the surface magnetic waveform of the Hall induction surface will become (as shown in Figure 1 Therefore, the magnetic field sensed by the Hall induction is not uniformly changed, which may cause poor starting and even failure.

[0005] Therefore, in view of the above situation, in order to improve the uniformity of the change of the magnetic field sensed by the Hall induction during the practical process of the Hall induction magnetic ring while meeting the demolding requirement of the injection molding magnetic ring, it is also necessary to further optimize the overall structure of the injection molding magnetic ring. UTILITY MODEL CONTENTS

[0006] The first object of the utility model is to provide a rotor magnetic ring, which solves the technical problems of considering the demolding requirement of the injection molding and the uniformity of the change of the magnetic field sensed by the Hall induction during the use process.

[0007] The second purpose of the utility model is to provide a motor, to solve the technical problem of optimizing its use performance.

[0008] The rotor magnetic ring is realized as follows:

[0009] A rotor magnetic ring comprises:

[0010] A magnetic ring body comprises a plurality of S-pole magnetic poles and N-pole magnetic poles arranged alternately and uniformly along a circumferential direction;

[0011] A plurality of material pushing portions are arranged uniformly on one axial end of the magnetic ring body along the circumferential direction; the center of each material pushing portion is located in an abutment area formed by adjacent S-pole magnetic poles and N-pole magnetic poles; the corresponding central angle of the abutment area is α = ± (360 / 2N)*0.2, wherein N is the number of magnetic pole pairs, N≥3, and the corresponding central angle of the abutment area is the bisector and zero line of the boundary line of the adjacent S-pole magnetic poles and N-pole magnetic poles.

[0012] In the optional implementation of the utility model, the number of the material pushing portions is not greater than the number of the magnetic pole pairs.

[0013] In the optional implementation of the utility model, the number of the material pushing portions is the same as the number of the magnetic pole pairs.

[0014] In the optional implementation of the utility model, all the material pushing portions are counterbores arranged on one axial end of the magnetic ring body, and the hole depths of all the material pushing portions are the same.

[0015] In the optional implementation of the utility model, a connecting column for matching a rotor shaft is formed at the axial center of the magnetic ring body; and

[0016] One axial end of the magnetic ring body is shaped with a first annular groove concentrically distributed with the connecting column, and the other axial end of the magnetic ring body is shaped with a second annular groove concentrically distributed with the connecting column;

[0017] The depths of the first annular groove and the second annular groove are the same or different.

[0018] In the optional implementation of the utility model, the inner diameter of the first annular groove is smaller than the inner diameter of the second annular groove; and

[0019] All the material pushing portions are arranged on the axial end of the magnetic ring body shaped with the first annular groove.

[0020] In the optional implementation of the utility model, the center of each material pushing portion is located on the center line formed by the inner and outer walls of the axial end face of the magnetic ring body.

[0021] The motor is realized as follows:

[0022] A motor comprises a stator assembly, a rotor assembly, and a front cover plate assembly and a rear cover plate assembly connected to two axial side ends of the stator assembly respectively; wherein

[0023] The rotor assembly comprises the rotor magnetic ring and a rotor shaft connected to the rotor magnetic ring;

[0024] The front cover plate assembly and the rear cover plate assembly are respectively provided with bearings for matching the rotor shaft.

[0025] In the optional implementation of the utility model, the rear cover plate assembly comprises a rear end cover connected to the stator assembly, and a rear cover plate for matching the rear end cover to form a chamber accommodating the bearing; wherein

[0026] When the bearing is assembled in the chamber, the rear cover plate is further formed with a receiving cavity for storing an oil body lubricating the bearing at an end of the bearing away from the rotor magnetic ring.

[0027] In the optional implementation of the utility model, a felt is further sleeved on the outer surface of the bearing in the chamber; and

[0028] An elastic clamping piece is further arranged on the side end of the felt facing the rotor magnetic ring in the chamber and clamping on the outer surface of the bearing.

[0029] By adopting the above technical scheme, the utility model has the following beneficial effects: the rotor magnetic ring and the motor applying the same can meet the demolding requirement of the rotor magnetic ring after injection molding processing is completed through the design of multiple ejection portions, the ejection portion is designed in the abutment area formed by the adjacent S-pole magnetic pole and N-pole magnetic pole, the magnetic field of the abutment area corresponding to other areas is weak, and the magnetic field strength of Hall induction cannot be reached, so the magnetic field of Hall induction will not be affected by the design of the ejection portion, thereby ensuring that the magnetic field waveform sensed by Hall induction during the use of the overall rotor magnetic ring is closer to a sine wave, the peak value difference is small, and the problems of poor starting and even failure are avoided. In addition, for the abutment area, the bisector of the adjacent S-pole magnetic pole and N-pole magnetic pole is used as the angle bisector to form a central angle, the precision requirement of the ejection portion design can be reduced, and the processing difficulty can be reduced under the premise that the ejection portion does not affect Hall induction.

[0030] Furthermore, for the overall motor, the design of the rear cover plate assembly can not only ensure the stability of the corresponding bearing position, but also reduce the relative friction between the bearing and the rotor shaft in combination with the design of the felt and the receiving cavity, thereby reducing the wear of the formed matching surface between the rotor shaft and the bearing, prolonging the service life of the rotor shaft. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1The schematic diagram of the magnetic field waveform of the rotor magnetic ring of the prior art sensed by a Hall;

[0032] Figure 2 The schematic diagram of the sectional structure of the rotor magnetic ring of the utility model;

[0033] Figure 3 The schematic diagram of the distribution structure of the material pushing part of the rotor magnetic ring of the utility model;

[0034] Figure 4 The schematic diagram of the structure of the magnetic pole and the adjacent area of the rotor magnetic ring of the utility model;

[0035] Figure 5 The schematic diagram of the magnetic field waveform of the rotor magnetic ring of the utility model sensed by a Hall;

[0036] Figure 6 The schematic diagram of the structure of the motor of the utility model;

[0037] Figure 7 The schematic diagram of the structure of the rear cover plate assembly of the motor of the utility model.

[0038] In the figure: magnetic ring body 1, material pushing part 11, connecting column 12, first annular groove 13, second annular groove 14, boundary line K, stator assembly 2, rotor shaft 3, front cover plate assembly 4, control plate 5, rear end cover 61, rear cover plate 62, accommodating cavity 63, felt 64, elastic clamping piece 65, baffle 66, bearing 7, gasket 8. DETAILED DESCRIPTION

[0039] In order to make the content of the utility model more easily understood clearly, the utility model is further explained in detail below according to specific embodiments and in conjunction with the drawings.

[0040] Embodiment 1:

[0041] Please refer to Figures 2 to 5 As shown in the figure, the embodiment provides a rotor magnetic ring, which comprises a magnetic ring body 1 and a plurality of material pushing parts 11 arranged on the magnetic ring body 1. For the magnetic ring body 1 of the embodiment, it can be formed into an injection molded permanent magnet ferrite magnetic ring by using injection molding method.

[0042] Specifically, first, the magnetic ring body 1 is roughly in a circular ring structure, which comprises a plurality of S-pole magnetic poles and N-pole magnetic poles arranged uniformly along the circumferential direction and alternately with each other. It can be understood that one S-pole magnetic pole and one N-pole magnetic pole form a magnetic pole pair.

[0043] Secondly, the plurality of material pushing portions 11 are evenly arranged on one of the axial side ends of the magnetic ring body 1 in the circumferential direction; the axial side end on which the material pushing portion 11 is designed is not absolutely limited in the embodiment. In the case of an optional implementation example shown in the drawings, a connecting column 12 for matching the rotor shaft 3 is formed at the axis of the magnetic ring body 1 from the perspective of reducing production. The connecting column 12 is referred to as a connecting column rather than a connecting hole mainly because a first annular groove 13 concentrically distributed with the connecting column 12 is formed at one of the axial side ends of the magnetic ring body 1, and a second annular groove 14 concentrically distributed with the connecting column 12 is formed at the other axial side end of the magnetic ring body 1. In this way, the amount of permanent magnetic material and the amount of injection molding material of the overall magnetic ring body 1 are reduced, and the reliability of the matching structure of the overall rotor magnetic ring and the rotor shaft 3 is ensured through the design of the connecting column 12. Moreover, the first annular groove 13 and the second annular groove 14 are not connected in the axial direction of the magnetic ring body 1, but an axial barrier connected with the connecting column 12 is formed between the first annular groove 13 and the second annular groove 14. The axial barrier needs to satisfy a certain thickness, thereby ensuring the reliability of the connecting column 12.

[0044] Based on the above structure, it is also necessary to point out that the first annular groove 13 and the second annular groove 14 can reduce the shrinkage amount in the injection molding process on the basis of reducing the injection molding material. In this regard, the depth of the first annular groove 13 and the second annular groove 14 can be the same or different, which is not absolutely limited in the embodiment.

[0045] It is also necessary to point out here that the radial dimension of the first annular groove 13 and the second annular groove 14 meets the design requirements of the material pushing portion 11 on the basis of reducing the material cost, ensures that the rotor magnetic ring can be quickly demolded in a stressed state during the demolding process, and the embodiment is designed as follows:

[0046] The inner diameter of the first annular groove 13 is smaller than the inner diameter of the second annular groove 14; and the plurality of material pushing portions 11 are arranged on the axial side end of the magnetic ring body 1 on which the first annular groove 13 is formed. That is, the area of the axial end face subjected to the thrust force during the demolding process is greater than the area of the other axial end face not directly subjected to the thrust force. In this structure, the center of each material pushing portion 11 can be further arranged on the center line formed by the inner and outer walls of the axial side end of the magnetic ring body 1, so that the thrust force of the ejector pin of the injection mold on the material pushing portion 11 is transmitted to the axial end face of the rotor magnetic ring more uniformly, and the demolding smoothness is also improved.

[0047] On the basis of the above structure, the next to be described is the specific design position of the material ejecting portion 11 on the axial end face of the magnetic ring body 1. Roughly speaking, the center of each material ejecting portion 11 is located in the adjacent area formed by the adjacent S-pole magnetic pole and N-pole magnetic pole. It also needs to be described that the corresponding central angle of the adjacent area is α = ± (360 / 2N) * 0.2, where N is the number of magnetic pole pairs, N ≥ 3, and the corresponding central angle of the adjacent area takes the boundary line K of the adjacent S-pole magnetic pole and N-pole magnetic pole as the angle bisector and zero line.

[0048] More specifically, theoretically, the magnetic field of the boundary line K of the adjacent S-pole magnetic pole and N-pole magnetic pole is the weakest, and it is the best position to set the center of each material ejecting portion 11 at the boundary line K, but this case requires high position accuracy of the material ejecting portion 11 and has high processing difficulty, therefore, the center of the material ejecting portion 11 is designed in the above adjacent area in the embodiment, the magnetic field of the adjacent area is weaker than that of other areas, and the magnetic field strength cannot reach the starting magnetic field strength of the Hall effect, so the design of the material ejecting portion 11 will not affect the magnetic field of the Hall effect, thereby ensuring that the magnetic field waveform sensed by the Hall effect during the use of the overall rotor magnetic ring is closer to a sine wave, and the peak value difference is small. Please refer to Figure 5 Thus, the problem of poor starting and even failure is avoided.

[0049] From the perspective of facilitating processing, the material ejecting portion 11 is designed as a counterbore formed on one axial side end of the magnetic ring body 1, at this time, since the material ejecting portion 11 is designed in the adjacent area with weak magnetic field, theoretically, the hole depth of all the material ejecting portions 11 can be deep or shallow, and can meet the use requirements, of course, from the most preferred case, the hole depths of all the material ejecting portions 11 are designed to be the same.

[0050] In addition, it also needs to be described that the number of material ejecting portions 11 in each adjacent area can be one, two or even more, when multiple material ejecting portions 11 are set, only the centers of the multiple material ejecting portions 11 need to be designed on the same radius line of the magnetic ring body 1 to not interfere with each other and act respectively, the number of material ejecting portions 11 to be designed in each adjacent area can be selected in combination with the size of the actual magnetic ring body 1, when the outer diameter size of the magnetic ring body 1 is large, the number of material ejecting portions 11 designed in each adjacent area can also be increased synchronously, the embodiment only takes the case of designing one material ejecting portion 11 in each adjacent area as an example, at this time, the number of material ejecting portions 11 is not greater than the number of magnetic pole pairs, based on this, preferably, the number of material ejecting portions 11 is designed to be the same as the number of magnetic pole pairs, which is beneficial to improve the demolding efficiency.

[0051] In summary, for the rotor magnetic ring of the embodiment, the precision requirement of the design of the material ejecting portion 11 can be reduced, thereby reducing the processing difficulty under the premise of meeting the condition that the material ejecting portion 11 does not affect the Hall effect.

[0052] Embodiment 2:

[0053] Referring to Figures 2 to 7 Based on the rotor magnetic ring of Embodiment 1, the motor of the present embodiment comprises a stator assembly 2, a rotor assembly, and a front cover plate assembly 4 and a rear cover plate assembly connected to the two axial side ends of the stator assembly 2 respectively; wherein the rotor assembly at least comprises the rotor magnetic ring of Embodiment 1 and a rotor shaft 3 connected to the rotor magnetic ring; the front cover plate assembly 4 and the rear cover plate assembly are respectively provided with bearings 7 for matching the rotor shaft 3.

[0054] In addition, it can be understood that the motor of the present embodiment also comprises a control board 5, the stator assembly 2 is connected to the control board 5 through the input of rated voltage, the control board 5 determines the position of the rotor shaft 3 through the rotor magnetic ring in combination with the Hall sensor designed thereon, and then outputs the corresponding voltage to the current winding to make the motor run.

[0055] Based on the above, further, the rear cover plate assembly comprises a rear end cover 61 connected to the stator assembly 2 and a rear cover plate 62 for matching the rear end cover 61 to form a chamber accommodating the bearing 7; wherein when the bearing 7 is assembled in the chamber, the rear cover plate 62 is further formed with a receiving cavity 63 for storing the oil body lubricating the bearing 7 at the end of the bearing 7 away from the rotor magnetic ring. Here, a baffle 66 for matching one axial side end of the rotor shaft 3 is also provided in the receiving cavity 63 to prevent friction between the rotor shaft 3 and the rear cover plate 62.

[0056] Based on the above structure, it is also necessary to point out that the rotor magnetic ring adopted in the present embodiment has the axial end face with the second annular groove 14 facing the rear cover plate assembly, and the axial end face with the first annular groove 13 facing the front cover plate assembly 4. For this purpose, in order to facilitate the assembly of the bearing 7 in the rear cover plate assembly, the rear end cover 61 is protruded towards the side of the rotor magnetic ring, and under the design of the second annular groove 14, the inner diameter D3 of the second annular groove 14 is greater than the outer circumferential side dimension D4 of the protruded part 611 of the rear end cover 61 towards the rotor magnetic ring, so that interference between the protruded end cover and the rotor magnetic ring can be avoided. Further, the control board 5 is located between the axial side end of the rotor magnetic ring with the first annular groove 13 and the front cover plate assembly 4, and the control board 5 is matched with the use of the rotor shaft 3, and a through hole suitable for the rotor shaft 3 to pass through is designed on the control board 5. For this purpose, the inner diameter D2 of the first annular groove 13 is designed to be smaller than the inner diameter D1 of the through hole of the control board 5, so that the projection of the Hall on the control board 5 towards the rotor magnetic ring can all fall into the axial end face of the rotor magnetic ring, so that the Hall can better sense the change of the magnetic poles of the rotor magnetic ring.

[0057] It is also needed to be explained in combination with the drawings that the end face of the connecting column 12 of the rotor magnetic ring towards the front cover plate assembly 4 is further provided with a gasket 8 sleeved on the rotor shaft 3, and the gap A1 between the gasket 8 and the bearing 7 in the front cover plate assembly 4 is smaller than the axial gap A2 formed between the end face of the rotor magnetic ring towards the front cover plate assembly 4 and the stator assembly 2, thereby preventing the interference caused by the movement between the rotor assembly and the stator assembly 2.

[0058] In addition, it is also necessary to be explained that the outer surface of the bearing 7 in the chamber is further sleeved with a felt 64, and the side end of the felt 64 towards the rotor magnetic ring in the chamber is further provided with an elastic clamping piece 65 for clamping on the outer surface of the bearing 7. The elastic clamping piece 65 can be selected as a spring piece.

[0059] In summary, for the motor of the embodiment, the cooperation between the felt 64 and the accommodating cavity 63 can form lubrication during the use of the bearing 7, and an oil film is formed between the rotor shaft 3 and the bearing 7, thereby reducing the friction coefficient, reducing the power, reducing the wear of the cooperation surface formed between the rotor shaft 3 and the bearing 7, and prolonging the service life of the rotor shaft 3.

[0060] The above specific embodiments further illustrate the purpose, technical scheme and beneficial effects of the utility model, and it should be understood that the above is only a specific embodiment of the utility model, and is not used to limit the utility model, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

[0061] In the description of the utility model, it should be understood that the terms indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and are not used to indicate or imply that the indicated device or element must have a specific orientation, structure and operation, and therefore cannot be understood as a limitation on the utility model.

[0062] In the utility model, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0063] In the description of the utility model, it is necessary to explain that the orientation or position relation indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is the orientation or position relation based on the drawings shown or the orientation or position relation commonly placed when the utility model product is used, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element indicated must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", "third" and the like are only used for distinguishing description, and cannot be understood as indicating or implying relative importance.

[0064] In addition, the terms "horizontal", "vertical", "overhang" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0065] In the utility model, unless otherwise explicitly specified and limited, the first feature above or below the second feature can include that the first and second features are in direct contact, or can include that the first and second features are not in direct contact but are in contact through another feature therebetween. Moreover, the first feature above, above and above the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature below, below and below the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

Claims

1. A rotor magnet ring, characterized by, The magnetic ring body comprises a plurality of S-pole magnetic poles and N-pole magnetic poles arranged uniformly and alternately along the circumferential direction; A plurality of top material portions are arranged uniformly on one axial side end of the magnetic ring body along the circumferential direction; the center of each top material portion is located in an adjacent area formed by adjacent S-pole magnetic poles and N-pole magnetic poles; the corresponding central angle of the adjacent area is α = ± (360 / 2N)*0.2, wherein N is the number of magnetic pole pairs, N≥3, and the corresponding central angle of the adjacent area is the bisector of the dividing line of the adjacent S-pole magnetic pole and N-pole magnetic pole and the zero line. The number of the top material portions is not more than the number of magnetic pole pairs.

2. The rotor magnet ring of claim 1, wherein The number of the top material portions is the same as the number of magnetic pole pairs.

3. The rotor magnet ring of claim 2, wherein All the top material portions are counterbores provided on one axial side end of the magnetic ring body, and the hole depths of all the top material portions are the same.

4. The rotor magnet ring according to any one of claims 1 to 3, characterized in that The magnetic ring body is formed with a connecting column at the axial center for matching the rotor shaft; and 5. The rotor magnet ring according to any one of claims 1 to 3, characterized in that One axial side end of the magnetic ring body is formed with a first annular groove concentrically distributed with the connecting column, and the other axial side end of the magnetic ring body is formed with a second annular groove concentrically distributed with the connecting column; The depths of the first annular groove and the second annular groove are the same or different. The inner diameter of the first annular groove is smaller than the inner diameter of the second annular groove; and 6. The rotor magnet ring of claim 5, wherein All the top material portions are provided on the axial side end of the magnetic ring body formed with the first annular groove. The center of each top material portion is located on the center line formed by the inner and outer walls of the axial side end surface of the magnetic ring body.

7. The rotor magnet ring of claim 6, wherein The magnetic ring body comprises a plurality of S-pole magnetic poles and N-pole magnetic poles arranged uniformly and alternately along the circumferential direction; 8. An electric machine characterized by A plurality of top material portions are arranged uniformly on one axial side end of the magnetic ring body along the circumferential direction; the center of each top material portion is located in an adjacent area formed by adjacent S-pole magnetic poles and N-pole magnetic poles; the corresponding central angle of the adjacent area is α = ± (360 / 2N)*0.2, wherein N is the number of magnetic pole pairs, N≥3, and the corresponding central angle of the adjacent area is the bisector of the dividing line of the adjacent S-pole magnetic pole and N-pole magnetic pole and the zero line. The number of the top material portions is not more than the number of magnetic pole pairs. The number of the top material portions is the same as the number of magnetic pole pairs. All the top material portions are counterbores provided on one axial side end of the magnetic ring body, and the hole depths of all the top material portions are the same. The magnetic ring body is formed with a connecting column at the axial center for matching the rotor shaft; and 9. The electric machine of claim 8, wherein, One axial side end of the magnetic ring body is formed with a first annular groove concentrically distributed with the connecting column, and the other axial side end of the magnetic ring body is formed with a second annular groove concentrically distributed with the connecting column; The depths of the first annular groove and the second annular groove are the same or different.

10. The electric machine of claim 9, wherein, The inner diameter of the first annular groove is smaller than the inner diameter of the second annular groove; and All the top material portions are provided on the axial side end of the magnetic ring body formed with the first annular groove. The center of each top material portion is located on the center line formed by the inner and outer walls of the axial side end surface of the magnetic ring body. The magnetic ring body comprises a plurality of S-pole magnetic poles and N-pole magnetic poles arranged uniformly and alternately along the circumferential direction; A plurality of top material portions are arranged uniformly on one axial side end of the magnetic ring body along the circumferential direction; the center of each top material portion is located in an adjacent area formed by adjacent S-pole magnetic poles and N-pole magnetic poles; the corresponding central angle of the adjacent area is α = ± (360 / 2N)*0.2, wherein N is the number of magnetic pole pairs, N≥3, and the corresponding central angle of the adjacent area is the bisector of the dividing line of the adjacent S-pole magnetic pole and N-pole magnetic pole and the zero line. The number of the top material portions is not more than the number of magnetic pole pairs. The number of the top material portions is the same as the number of magnetic pole pairs. All the top material portions are counterbores provided on one axial side end of the magnetic ring body, and the hole depths of all the top material portions are the same. The magnetic ring body is formed with a connecting column at the axial center for matching the rotor shaft; and One axial side end of the magnetic ring body is formed with a first annular groove concentrically distributed with the connecting column, and the other axial side end of the magnetic ring body is formed with a second annular groove concentrically distributed with the connecting column; The depths of the first annular groove and the second annular groove are the same or different. The inner diameter of the first annular groove is smaller than the inner diameter of the second annular groove; and All the top material portions are provided on the axial side end of the magnetic ring body formed with the first annular groove. The center of each top material portion is located on the center line formed by the inner and outer walls of the axial side end surface of the magnetic ring body.

Images