Permanent magnet motor

Abstract

The invention discloses a permanent magnet motor. The permanent magnet motor comprises a shell, a stator and a rotor. The stator includes a yoke, a plurality of first teeth, a plurality of second teeth, and a plurality of ring windings. The yoke part is in a ring shape, and the multiple first tooth parts are installed on the inner diameter surface of the yoke part in the circumferential direction of the yoke part and fixed to the shell. The plurality of second tooth parts are mounted on the outer diameter surface of the yoke part in the circumferential direction of the yoke part; and each annular winding is sleeved on the yoke part. The rotor comprises a rotating shaft assembly, a plurality of permanent magnets, a first sheath and a second sheath. The rotor is rotationally connected with the shell, an annular groove is formed in the rotating shaft assembly, and the multiple permanent magnets are distributed in the annular groove in the circumferential direction of the rotating shaft assembly; the first sheath is wound on the plurality of permanent magnets, and the second sheath is sleeved on the first sheath. Through the arrangement, the stator is divided into three parts, and the permanent magnet is wrapped by the first sheath and the second sheath, so that the structural strength of the permanent magnet motor is improved, and the loss of the permanent magnet motor in the operation process is reduced.

Description

Technical Field

[0001] The present application relates to the field of motor technology, and in particular to a permanent magnet motor. Background Art

[0002] The existing permanent magnet motor includes a stator and a rotor. The stator includes a yoke, a stator tooth and a coil winding. For high-power density high-speed permanent magnet motors (i.e., permanent magnet motors with a rotation speed greater than or equal to 100,000 rpm and a power density greater than or equal to 15 kW / kg), the existing structure in which the yoke is connected to the stator tooth makes the length of the coil winding sleeved on the yoke longer. Since the length of the permanent magnet needs to be compatible with the length of the coil winding, the length of the permanent magnet is longer, which makes the length of the rotor carrying the permanent magnet longer, resulting in an increase in the overall length of the permanent magnet motor, thereby reducing the structural strength of the permanent magnet motor. Secondly, in high-power density high-speed permanent magnet motors, a plurality of permanent magnets are arranged on the surface of the rotor, but no reinforcement structure is arranged for the permanent magnets. Therefore, during the rotation of the rotor, the permanent magnets are easily separated from the rotor under the action of centrifugal force, further reducing the structural strength of the permanent magnet motor.

[0003] In addition, the material type used in the stator of the existing permanent magnet motor is conventional and single, resulting in problems such as low magnetic permeability, high coercive force, low resistivity and high energy loss during the operation of the permanent magnet motor, which affects the efficiency and working stability of the permanent magnet motor, and further increases the loss of the permanent magnet motor.

[0004] Therefore, how to improve the structural strength of the permanent magnet motor and reduce the loss of the permanent magnet motor is a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present application is to provide a permanent magnet motor that can improve structural strength and reduce losses.

[0006] To achieve the above objectives, this application adopts the following technical solutions: A permanent magnet motor includes a housing, a stator and a rotor. The stator includes a yoke, a plurality of first teeth, a plurality of second teeth and a plurality of winding groups. The yoke is made of a first material and is in a ring shape; the first teeth are made of a first material, and a plurality of first teeth are installed on the inner diameter surface of the yoke along the circumference of the yoke and fixed to the housing; the second teeth are made of a second material, and a plurality of second teeth are installed on the outer diameter surface of the yoke along the circumference of the yoke, and each second tooth corresponds to a first tooth along the radial direction of the yoke, so that each second tooth cooperates with a corresponding first tooth to form a stator tooth; each annular winding is sleeved on the yoke, and an annular winding is arranged between two adjacent stator teeth. The rotor includes a shaft assembly, a plurality of permanent magnets, a first sleeve and a second sleeve. The rotor is surrounded by a plurality of first teeth, and the rotor is rotatably connected to the housing so that the rotor can rotate relative to the stator. An annular groove is provided on the rotating shaft assembly, and the opening of the annular groove is located on the outer surface of the rotating shaft assembly; multiple permanent magnets are in the shape of a fan ring, and the multiple permanent magnets are distributed in the annular groove along the circumference of the rotating shaft assembly; a first sheath is wound around the multiple permanent magnets, and the first sheath is made of an amorphous alloy; a second sheath is arranged on the first sheath and is interference fit with the first sheath.

[0007] Furthermore, the second sheath is made of carbon fiber material.

[0008] Furthermore, the shaft assembly includes a first shaft and a second shaft. The first shaft has a mounting groove formed therein, an annular groove formed on the first shaft, and an opening of the annular groove is located on the outer surface of the first shaft; the second shaft is at least partially located in the mounting groove and fixed to the mounting groove.

[0009] Furthermore, the annular groove is consistent with the permanent magnet in length along the axial direction of the first rotating shaft; the lengths of the first sleeve and the second sleeve in the axial direction of the first rotating shaft are greater than the length of the annular groove in the axial direction of the first rotating shaft.

[0010] Furthermore, the second rotating shaft is provided with a plurality of weight-reducing grooves, which are evenly distributed on the outer diameter surface of the second rotating shaft along the circumference of the second rotating shaft, and the openings of the plurality of weight-reducing grooves face the first rotating shaft.

[0011] Further, the two ends of the first rotating shaft along its axial direction are defined as a first section and a second section respectively, the length of the first section along the axial direction of the first rotating shaft is consistent with the length of the second section along the axial direction of the first rotating shaft; the volume of the first section is greater than the volume of the second section; or an extension piece is provided on the first section for increasing the volume of the first section, and the extension piece is fixed on the first section or integrally formed with the first section.

[0012] Furthermore, the first material is an amorphous alloy, and the second material is a soft magnetic composite material.

[0013] Furthermore, a first stator slot is formed between two adjacent first tooth portions, and a second stator slot is formed between two adjacent second tooth portions, and each first stator slot and a second stator slot cooperate to form a winding slot for accommodating an annular winding; the end of the second tooth portion away from the yoke portion is a slot end, and both sides of the slot end along the circumference of the yoke portion extend along the circumference of the yoke portion, so that the second tooth portion presents a "T"-shaped structure.

[0014] Furthermore, both the first tooth portion and the second tooth portion extend radially along the yoke portion, a first protrusion structure is formed on the surface of each first tooth portion close to the yoke portion, a plurality of first groove structures and a plurality of second protrusion structures are respectively provided at both ends of the yoke portion along the radial direction, a second groove structure is formed on the surface of each second tooth portion close to the yoke portion, each first protrusion structure is clamped and fixed to a first groove structure, and each second protrusion structure is clamped and fixed to a second groove structure.

[0015] Furthermore, the yoke is provided with a plurality of cooling holes for cooling the yoke and / or the annular winding, each cooling hole is arranged to penetrate the yoke along the axial direction of the yoke; each cooling hole corresponds to a first tooth portion and a second tooth portion along the radial direction of the yoke.

[0016] The above-mentioned permanent magnet motor can reduce the axial length of the annular winding sleeved on the yoke by splitting the stator tooth portion into the first tooth portion and the second tooth portion and connecting them to the yoke portion, thereby reducing the length of the permanent magnet, and then reducing the overall length of the permanent magnet motor, so as to improve the structural strength of the permanent magnet motor. In addition, the first sheath and the second sheath are wrapped around the outside of the permanent magnet, so as to apply a preload force toward the axis of the rotating shaft assembly on the permanent magnet, so as to prevent the permanent magnet from being separated from the rotating shaft assembly due to the centrifugal force during rotation, so as to further improve the structural strength of the permanent magnet motor. At the same time, the first tooth portion and the yoke portion and the second tooth portion are made of different materials, which can also reduce the loss of the permanent magnet motor during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 An exploded diagram of the permanent magnet motor provided in an embodiment of the present application.

[0018] Figure 2 A cross-sectional view of a rotor provided in an embodiment of the present application.

[0019] Figure 3 A structural diagram of the stator and rotor installation provided in an embodiment of the present application.

[0020] Figure 4 A structural diagram of a stator provided in an embodiment of the present application.

[0021] Figure 5 An exploded view of a stator provided in an embodiment of the present application.

[0022] Figure 6This is a waveform diagram of the time variation of permanent magnet loss provided in an embodiment of the present application.

[0023] Figure 7 This is a force analysis diagram of the carbon fiber sheath in a motor without an amorphous alloy sheath.

[0024] Figure 8 This is a force analysis diagram of a carbon fiber sheath in a motor provided with an amorphous alloy sheath according to an embodiment of the present application.

[0025] Fig. 9 A Campbell diagram for modal analysis of a permanent magnet motor rotor provided in an embodiment of the present application.

[0026] Fig.10 Another Campbell diagram for permanent magnet motor rotor modal analysis provided in an embodiment of the present application.

[0027] Fig.11 A cross-sectional view of a rotor from another perspective provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the specific implementation manner of the present application will be clearly and completely described below in conjunction with the drawings in the implementation manner of the present application.

[0029] It should be noted that the words "first", "second" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not indicate a quantitative limitation, but indicate the existence of at least one. "Multiple" or "several" means at least two. Unless otherwise specified, words such as "front", "back", "left", "right", "bottom" and / or "top" are only for the convenience of description and are not limited to one position or one spatial orientation. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect.

[0030] The singular forms "a", "said" and "the" used in this specification and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0031] like Figure 1, Figure 2 and Figure 3 As shown, the present application provides a permanent magnet motor 100, which includes a housing 11, a stator 12 and a rotor 13. The housing 11 is the basic frame of the permanent magnet motor 100, which is used to support the stator 12 and the rotor 13. The stator 12 is fixed in the housing 11, and the stator 12 is used to generate a rotating magnetic field. The rotor 13 is surrounded by the stator 12, and the rotor 13 is rotatably connected to the housing 11 so that the rotor 13 can rotate relative to the stator 12, and the rotor 13 can cooperate with the rotating magnetic field to generate electromagnetic torque.

[0032] In order to clearly illustrate the technical solution of this application, the following is also defined: Figure 1 The front, rear, left, right, top and bottom shown are used to represent the front, rear, left, right, top and bottom of the permanent magnet motor 100 .

[0033] Specifically, the stator 12 includes a yoke 121, a plurality of first teeth 122, a plurality of second teeth 123, and a plurality of annular windings 125. The yoke 121 is made of a first material and is in a ring shape. The first teeth 122 are made of a first material, and a plurality of first teeth 122 are mounted on the inner diameter surface of the yoke 121 along the circumference of the yoke 121 and fixed to the housing 11. The second teeth 123 are made of a second material, and a plurality of second teeth 123 are mounted on the outer diameter surface of the yoke 121 along the circumference of the yoke 121.

[0034] Through the above configuration, the yoke 121 is configured to be in a ring shape, so that the first tooth portion 122 disposed on the inner side of the yoke 121 does not occupy additional space, thereby reducing the space occupied by the stator 12 to improve the compactness of the permanent magnet motor 100 structure, thereby improving the structural strength of the permanent magnet motor 100.

[0035] At the same time, the winding can form an annular winding 125 on the annular body, and the annular winding 125 does not need to be cross-wound at the winding end, which is beneficial to reducing the length of the annular winding 125, so as to reduce the length of the stator 12, thereby reducing the length of the permanent magnet motor 100, and further reducing the space occupancy rate of the permanent magnet motor 100, so that the power density per unit volume of the permanent magnet motor 100 can be increased, so as to improve the operating power of the motor.

[0036] In addition, the use of the annular winding 125 can reduce the total length of the winding, and reduce the resistance and loss of the winding, so that it can be adapted to the permanent magnet motor 100 with a short axial length and a small number of poles, thereby improving the adaptability of the annular winding 125. In addition, the annular winding 125 can increase the filling rate of the winding in the iron core of the stator 12, thereby improving the compactness of the structure of the permanent magnet motor 100, thereby improving the power density of the permanent magnet motor 100, and improving the performance of the permanent magnet motor 100.

[0037] In the present application, the yoke 121 is split into a plurality of arc segments so as to facilitate the annular winding 125 to be disposed on the yoke 121 .

[0038] It should be noted that the present application does not impose any restrictions on the number and arc lengths of the arc segments into which the yoke 121 is split, and it is only required that the annular winding 125 can be set on the yoke 121 .

[0039] At the same time, the outer diameter of the first tooth portion 122 is substantially consistent with the inner diameter of the stator 12 yoke portion 121, and the inner diameter of the second tooth portion 123 is consistent with the outer diameter of the stator 12 yoke portion 121, so that the stator tooth portion 124 and the yoke portion 121 can be clearance-matched, thereby facilitating the assembly convenience of the stator tooth portion 124 and the stator 12 yoke portion 121. In addition, the tightness of the connection between the stator tooth portion 124 and the stator 12 yoke portion 121 can also be improved, thereby facilitating the stability of the clearance fit between the stator tooth portion 124 and the stator 12 yoke portion 121, so as to improve the overall structural strength of the permanent magnet motor 100.

[0040] More specifically, each second tooth portion 123 corresponds to a first tooth portion 122 along the radial direction of the yoke portion 121, so that each second tooth portion 123 cooperates with a corresponding first tooth portion 122 to form a stator tooth portion 124. An annular winding 125 is provided between two adjacent stator teeth 124, and each annular winding 125 is sleeved on the yoke portion 121, and the annular winding 125 is used to cooperate with the stator tooth portion 124 and the yoke portion 121 to generate a rotating magnetic field.

[0041] Through the above-mentioned arrangement, the stator 12 is split into the first tooth portion 122, the second tooth portion 123 and the yoke portion 121, which can reduce the length of the end portion of the annular winding 125 arranged on the stator 12, thereby reducing the axial length of the annular winding 125. Since the axial length of the permanent magnet 132 needs to be compatible with the axial length of the annular winding 125, the length of the permanent magnet 132 can also be correspondingly reduced, so that the axial length of the rotating shaft assembly 131 carrying the permanent magnet 132 can also be correspondingly reduced, thereby reducing the axial length of the permanent magnet motor 100 to improve the structural strength of the permanent magnet motor 100.

[0042] In addition, the annular winding 125 can be evenly wound on the stator 12, which can avoid excessive concentration of the local magnetic field on the stator 12, making the magnetic field distribution more uniform, thereby reducing harmonic losses. At the same time, the annular winding 125 is arranged on the stator 12 in the above manner, which can also reduce the leakage of the permanent magnet motor 100 during operation, thereby improving the energy transmission efficiency of the permanent magnet motor 100, further reducing the harmonic loss caused by the leakage of the magnetic field, and reducing the loss of the permanent magnet motor 100 during operation.

[0043] For example, in the present application, the annular winding 125 adopts a Litz wire structure, and a plurality of thin wires are twisted or woven into the wires in the annular winding 125. The Litz wire structure can effectively reduce the uneven current distribution caused by the skin effect and the proximity effect under high-frequency conditions, thereby reducing the high-frequency loss of the annular winding 125. In addition, the annular winding 125 adopts a Litz wire structure, which can be more tightly filled into the winding slot 128, thereby increasing the density of the induced magnetic field, and further increasing the power density of the annular winding 125 when it is working.

[0044] At the same time, twisting a plurality of thin wires to form the wires in the annular winding 125 can increase the contact area between the wires and the external environment, thereby improving the heat dissipation of the wires, so that when the permanent magnet motor 100 is working, the annular winding 125 can quickly transfer the generated heat to the outside world, avoiding the annular winding 125 from overheating and affecting the normal operation of the permanent magnet motor 100, thereby improving the service life and working stability of the annular winding 125. In addition, the above-mentioned wire formation method can also make the current evenly distributed in each thin wire, thereby avoiding excessive concentration of current in a single wire, causing local overheating of the wire, so as to improve the working performance of the annular winding 125.

[0045] It should be noted that the present application does not limit the structure of the annular winding 125 , and only needs to reduce the loss of the annular winding 125 .

[0046] In this embodiment, the rotor 13 includes a shaft assembly 131, a plurality of permanent magnets 132, a first sleeve 133 and a second sleeve 134. The rotor 13 is surrounded by a plurality of first teeth 122, and the rotor 13 is rotatably connected to the housing 11 so that the rotor 13 can rotate relative to the stator 12. An annular groove 1311b is provided on the shaft assembly 131, and the opening of the annular groove 1311b is located on the outer surface of the shaft assembly 131. The shaft assembly 131 serves as the main frame of the rotor 13 and is used to support the permanent magnet 132, the first sleeve 133 and the second sleeve 134. The permanent magnet 132 is in the shape of a fan ring and is used to provide a constant magnetic field in the permanent magnet motor 100, so that the magnetic field can cooperate with the rotating magnetic field generated by the stator 12 to drive the shaft assembly 131 to rotate. A plurality of permanent magnets 132 are distributed in the annular groove 1311b along the circumference of the shaft assembly 131. The first sheath 133 is made of amorphous alloy and is wound on the plurality of permanent magnets 132 , while the second sheath 134 is sleeved on the first sheath 133 and is interference fit with the first sheath 133 .

[0047] Through the above-mentioned arrangement, the first sleeve 133 and the second sleeve 134 can provide a pre-tightening force to the permanent magnet 132 toward the axis center of the shaft assembly 131, which can prevent the permanent magnet 132 from separating from the shaft assembly 131 due to the centrifugal force during the rotation of the shaft assembly 131, thereby helping to improve the connection stability between the permanent magnet 132 and the shaft assembly 131, thereby improving the structural strength of the permanent magnet motor 100 during rotation.

[0048] Moreover, the amorphous alloy has a relatively high magnetic permeability. The first sheath 133 is made of an amorphous alloy, so that the first sheath 133 surrounding the permanent magnet 132 can form a pole shoe layer, thereby making the magnetic field generated by the permanent magnet 132 more evenly distributed, which is beneficial to improving the operating power of the permanent magnet motor 100. Secondly, the amorphous alloy material has the characteristics of high saturation magnetic induction intensity and low energy loss, so that the first sheath 133 can concentrate on bearing the induced eddy current caused by the armature reaction in the permanent magnet motor 100, so as to avoid the permanent magnet 132 bearing the induced eddy current and causing the permanent magnet 132 to have an excessively high temperature, thereby avoiding the permanent magnet 132 from having an excessively high temperature and causing the permanent magnet 132 to lose its magnetism at high temperature, so as to improve the service life of the permanent magnet 132.

[0049] In addition, an annular winding 125 is provided on the stator 12. Since the length of the end of the annular winding 125 is shorter than the length of the end of the conventional winding, the length of the annular winding 125 in the present application is shortened in the axial direction. The length of the permanent magnet 132 is adapted to the length of the annular winding 125, thereby shortening the length of the permanent magnet 132, thereby shortening the length of the first sheath 133 and the second sheath 134 that wrap the permanent magnet 132. At the same time, the rotor 13 is arranged in the first tooth portion 122, and the first tooth portion 122 needs to completely cover the first sheath 133 and the second sheath 134, so the length of the first tooth portion 122 in the axial direction will also be shortened accordingly, and the lengths of the first tooth portion 122, the yoke portion 121 and the second tooth portion 123 are adapted, thereby shortening the length of the stator 12 in the axial direction, thereby shortening the length of the entire permanent magnet motor 100 in the axial direction, so as to improve the structural strength of the permanent magnet motor 100.

[0050] like Figure 6 As shown in FIG. 1 , as an embodiment, the time-varying waveform of the loss of the permanent magnet 132 is shown. The horizontal axis is the motor running time, the vertical axis is the loss of the permanent magnet 132, and the time-varying waveform of the loss of the permanent magnet 132 provided with the pole shoe layer is shown in FIG. Figure 4 The green line in the middle shows the time variation waveform of the loss of the permanent magnet 132 without the pole shoe layer, as shown in FIG. Figure 4 As shown by the red line. Figure 4It can be seen that during the operation of the permanent magnet motor 100, the loss of the permanent magnet 132 provided with the pole shoe layer is maintained between 8W and 9W; while the loss of the permanent magnet 132 without the pole shoe layer is maintained between 11W and 12W, so the loss of the permanent magnet 132 in the present application is reduced by about 26% relative to the permanent magnet 132 without the pole shoe layer. It can be understood that by providing the pole shoe layer on the permanent magnet 132, the loss can be effectively reduced, thereby reducing the loss of the permanent magnet motor 100 during operation.

[0051] In addition, the permanent magnet motor 100 generates armature reaction during power-on operation, which causes magnetic field distortion in the permanent magnet motor 100, and then causes induced eddy currents to be formed in the components of the permanent magnet motor 100, so that the components generate energy loss and heat. By utilizing the characteristic that the amorphous alloy has a high saturation magnetic induction intensity compared to the permanent magnet 132, the induced eddy currents formed by the armature reaction in the permanent magnet motor 100 can be concentrated on the first sheath 133. Moreover, the amorphous alloy has lower energy loss than the permanent magnet 132, which can avoid excessive energy loss and excessive heat generated by the induced eddy current on the first sheath 133, thereby reducing the heat generated by the permanent magnet motor 100 during operation, thereby reducing the heat dissipation pressure of the permanent magnet motor 100, so as to improve the operating power of the permanent magnet motor 100.

[0052] As an implementation mode, the second sheath 134 is made of carbon fiber material. Through the above-mentioned setting, the carbon fiber material has a high structural strength. The second sheath 134 made of carbon fiber material wraps the first sheath 133 and the permanent magnet 132, and a pre-tightening force toward the axis of the shaft assembly 131 can be applied to the first sheath 133 and the permanent magnet 132, so that the first sheath 133 and the permanent magnet 132 will not be separated from the shaft assembly 131 during the rotation of the shaft assembly 131, which is beneficial to improve the overall structural strength of the rotor 13. Secondly, the carbon fiber material has the characteristics of being basically non-magnetic and non-conductive, so that eddy current losses caused by electrical and magnetic conductivity can be avoided on the second sheath 134, which is beneficial to improve the operating performance of the permanent magnet motor 100.

[0053] Secondly, by setting the first sleeve 133 between the second sleeve 134 and the permanent magnet 132, the shear force generated by the rotation of the shaft assembly 131 on the second sleeve 134 can be reduced, so as to avoid the second sleeve 134 being borne too much shear force and causing the second sleeve 134 to fall off or break, which is beneficial to improve the installation stability of the second sleeve 134 on the shaft assembly 131, and further improve the structural strength of the permanent magnet motor 100.

[0054] In addition, by winding the first sheath 133 made of amorphous alloy on the outside of the rotor, and then winding the second sheath 134 made of carbon fiber on the outside of the first sheath 133, it is possible to avoid the problem of large eddy current loss when the permanent magnet motor 100 is running when the metal alloy protective sheath is used alone, thereby extending the service life of the permanent magnet motor 100. It is also possible to avoid the problem of restricting the critical speed of the permanent magnet motor 100 when the carbon fiber protective sheath is used alone, because the carbon fiber is arranged on the outside of the rotor 13 and has poor shear resistance. Therefore, by arranging the first sheath 133 made of amorphous alloy in the second sheath 134 made of carbon fiber, the influence of shear force on the second sheath 134 can be reduced, and the critical speed of the permanent magnet motor 100 can be increased; at the same time, the first sheath 133 made of amorphous alloy can also form a magnetic steel pole shoe outside the permanent magnet 132, so that the high-order harmonic magnetic flux is short-circuited, thereby effectively reducing the magnetic steel loss, and then improving the performance of the permanent magnet motor 100.

[0055] like Figure 7 and Figure 8 As shown in FIG. 1 , as an implementation method, the force analysis diagram of the carbon fiber sheath is calculated at the same motor speed. Figure 5 is a force analysis diagram of a carbon fiber sheath in a permanent magnet motor 100 without an amorphous alloy sheath, Figure 6 This is a force analysis diagram of the carbon fiber sheath of the permanent magnet motor 100 with an amorphous alloy sheath. It can be seen that the shear stress (maximum value of 101.27MPa) borne by the second sheath 134 of the permanent magnet motor 100 of the present application is less than the shear stress (106.82MPa) borne by the carbon fiber sheath in the permanent magnet motor 100 without an amorphous alloy sheath. In addition, the range of shear stress greater than 100MPa borne by the second sheath 134 of the permanent magnet motor 100 of the present application is less than the range of shear stress greater than 100MPa borne by the carbon fiber sheath in the motor without an amorphous alloy sheath.

[0056] Through the above-mentioned setting, the shear stress borne by the second sheath 134 of the permanent magnet motor 100 of the present application is less than the shear stress borne by the carbon fiber sheath in the motor without an amorphous alloy sheath, so that the second sheath 134 in the permanent magnet motor 100 of the present application can withstand a higher motor speed, which is beneficial to increase the critical speed of the permanent magnet motor 100, so as to improve the operating performance of the permanent magnet motor 100.

[0057] In addition, by setting the first sheath 133 and the second sheath 134, the air gap thickness in the permanent magnet motor 100 can be reduced, thereby weakening the air gap magnetic field in the permanent magnet motor 100, and further reducing the air gap harmonics generated by the air gap magnetic field, which is beneficial to reduce the energy loss caused by the air gap harmonics and further improve the operating performance of the permanent magnet motor 100.

[0058] like Fig. 9 and Fig.10 As shown in FIG. 1 , the relationship between the rotation speed and frequency of the permanent magnet motor 100 in different modes. Figure 7 is a Campbell diagram for the rotor modal analysis of the permanent magnet motor 100 in this application, Figure 7 The position of the red triangle in the middle is the critical speed of the permanent magnet motor 100 in this application, which is 44878 rpm; Figure 8 The Campbell diagram for the modal analysis of the rotor of a normal permanent magnet motor 100 is shown in Figure 1. Figure 8 The red triangle in the middle is the critical speed of the permanent magnet motor 100 in this application, which is 25269 rpm. Therefore, the critical speed of the permanent magnet motor 100 in this application is significantly improved compared with the ordinary permanent magnet motor 100, thereby improving the operating performance of the permanent magnet motor 100.

[0059] like Figure 2 and Fig.11 As shown, as an embodiment, the shaft assembly 131 includes a first shaft 1311 and a second shaft 1312. A mounting groove 1311a is provided in the first shaft 1311, and an annular groove 1311b is provided on the first shaft 1311, and the opening of the annular groove 1311b is located on the outer surface of the first shaft 1311. The second shaft 1312 is at least partially located in the mounting groove 1311a and fixed to the mounting groove 1311a. Through the above arrangement, the mass of the first shaft 1311 can be reduced by providing the mounting groove 1311a, thereby reducing the overall moment of inertia of the rotor 13, and further increasing the critical speed of the permanent magnet motor 100. Secondly, fixing the second shaft 1312 in the mounting groove 1311a can improve the structural strength of the first shaft 1311, thereby further improving the overall structural strength of the permanent magnet motor 100.

[0060] At the same time, in the present application, the second rotating shaft 1312 is a hollow shaft, so that the weight of the second rotating shaft 1312 can be reduced, so that the overall weight of the rotor 13 can be reduced while meeting the strength requirements, and the overall rotational inertia of the rotor 13 can be reduced, so that the critical speed of the permanent magnet motor 100 is further increased, thereby improving the working efficiency of the permanent magnet motor 100.

[0061] It should be noted that the present application does not impose any limitation on the structure of the second rotating shaft 1312 , and only needs to reduce the weight of the second rotating shaft 1312 .

[0062] As an embodiment, the annular groove 1311b is consistent with the length of the permanent magnet 132 along the axial direction of the first rotating shaft 1311. Through the above arrangement, it is possible to avoid the permanent magnet 132 from being deflected left and right in the annular groove 1311b during the rotation of the rotor 13, thereby improving the tightness of the permanent magnet 132 installed in the annular groove 1311b, and further improving the structural strength of the permanent magnet 132 installed on the first rotating shaft 1311.

[0063] As an embodiment, the annular groove 1311b is consistent with the length of the permanent magnet 132 along the axial direction of the first rotating shaft 1311; the length of the first sleeve 133 and the second sleeve 134 along the axial direction of the first rotating shaft 1311 is greater than the length of the annular groove 1311b along the axial direction of the first rotating shaft 1311. Through the above configuration, the first sleeve 133 and the second sleeve 134 can completely cover the permanent magnet 132, so as to avoid the permanent magnet 132 being exposed to the air gap and causing the permanent magnet 132 to be demagnetized due to the magnetic field distortion in the air gap, thereby facilitating the improvement of the service life of the permanent magnet 132. At the same time, the first sleeve 133 and the second sleeve 134 can completely wrap the permanent magnet 132, so that the permanent magnet 132 is in close contact with the first rotating shaft 1311, thereby preventing the permanent magnet 132 from being separated from the first rotating shaft 1311 during the rotation of the rotating shaft assembly 131, so as to improve the structural strength of the permanent magnet motor 100.

[0064] As an embodiment, the second rotating shaft 1312 is provided with a plurality of weight reducing grooves 1312a, which are evenly distributed on the outer diameter surface of the second rotating shaft 1312 along the circumference of the second rotating shaft 1312, and the openings of the plurality of weight reducing grooves 1312a face the first rotating shaft 1311.

[0065] Through the above configuration, the weight-reducing groove 1312a can further reduce the weight of the second rotating shaft 1312, thereby further reducing the overall moment of inertia of the rotor 13. Moreover, the configuration of the weight-reducing groove 1312a can reduce the weight of the second rotating shaft 1312 on the premise that the strength requirement of the second rotating shaft 1312 is met, thereby reducing the overall moment of inertia of the rotor 13 on the premise that the rotor 13 as a whole can meet the strength requirement, so as to help improve the power density of the permanent magnet motor 100 and reduce the loss during operation.

[0066] In the present application, the weight-reducing groove 1312a may be a honeycomb groove structure, so that the second rotating shaft 1312 can reduce its own weight while taking into account the stiffness, thereby increasing the critical speed of the permanent magnet motor 100 to improve the power density of the permanent magnet motor 100.

[0067] It should be noted that the present application does not limit the structure of the weight-reducing groove 1312 a , and it only needs to reduce the weight of the second rotating shaft 1312 while maintaining the rigidity of the second rotating shaft 1312 .

[0068] As an implementation manner, the two ends of the first rotating shaft 1311 along its axial direction are defined as a first section 1311c and a second section 1311d, respectively; the length of the first section 1311c along the axial direction of the first rotating shaft 1311 is consistent with the length of the second section 1311d along the axial direction of the first rotating shaft 1311; the volume of the first section 1311c is greater than the volume of the second section 1311d; or the first section 1311c is provided with an extension piece for increasing the volume of the first section 1311c, and the extension piece is fixed on the first section 1311c or is integrally formed with the first section 1311c.

[0069] Through the above arrangement, the volume on the first rotating shaft 1311 can be increased, and the volume difference between the first section 1311c and the second section 1311d can change the air gap thickness at the first section 1311c and the second section 1311d in the permanent magnet motor 100, thereby changing the flow diameter of the air in the air gap. Therefore, when the rotor 13 rotates to drive the air in the air gap to flow, the air is restricted by the change in the air gap flow diameter, which reduces the air flow in the air gap, thereby forming a low vacuum state in the air gap, thereby reducing the amount of contact between the rotor 13 and the air in the air gap, so as to reduce the wear caused by the contact between the rotor 13 and the air during the rotation process, and reduce the noise caused by the contact between the rotor 13 and the air during the rotation process, thereby helping to increase the service life of the rotor 13 and reduce the operating noise of the permanent magnet motor 100.

[0070] As an embodiment, the first material is an amorphous alloy, and the second material is a soft magnetic composite material. Through the above-mentioned arrangement, the yoke 121 and the first tooth portion 122 are made of amorphous alloy as the manufacturing material, which can reduce iron loss and improve magnetic permeability. The second tooth portion 123 is made of soft magnetic composite material. According to the characteristic of high resistivity of the soft magnetic composite material, the eddy current loss around the annular winding 125 can be reduced. At the same time, the soft magnetic composite material can also be pressed into second teeth 123 of different shapes to meet the structural requirements of the second teeth 123 in different permanent magnet motors 100, so as to facilitate the wiring arrangement of different annular windings 125, thereby improving the operating efficiency of the permanent magnet motor 100 and reducing the loss during operation.

[0071] Secondly, the use of pure amorphous core still has the problems of brittle performance, low tensile strength and poor thermal conductivity. Therefore, amorphous alloy is used to make the yoke 121 and the first tooth portion 122, and soft magnetic composite material is used to make the second tooth portion 123. By utilizing the low loss characteristics of amorphous alloy, the iron loss and eddy current loss of the stator 12 during operation can be reduced, thereby reducing the loss of the permanent magnet motor 100 during operation. At the same time, by utilizing the high magnetic permeability and mechanical strength characteristics of the soft magnetic composite material, the second tooth portion 123 can optimize the air gap magnetic field distribution, thereby improving the mechanical stress resistance of the stator 12, so as to improve the structural strength of the stator 12, and then improve the structural strength of the permanent magnet motor 100.

[0072] In addition, the use of amorphous materials and soft magnetic composite materials to make different parts of the stator 12 can avoid the problem that the loss of the permanent magnet motor 100 increases with the increase of the speed of the permanent magnet motor 100 when only silicon steel is used as the material to make the stator 12; it can also avoid the problem that the stator 12 is damaged due to centrifugal force and vibration during high-speed operation when only amorphous materials are used to make the stator 12, thereby improving the structural strength of the permanent magnet motor 100. In addition, amorphous materials have the problem of low magnetic saturation strength (that is, the magnetic saturation strength of amorphous materials is greater than or equal to 1.2T and less than or equal to 1.5T). Using amorphous materials and soft magnetic composite materials to make different parts of the stator 12 can also reduce the design restrictions on the high magnetic flux density of the permanent magnet motor 100, thereby improving the performance of the permanent magnet motor 100.

[0073] like Figure 4 and Figure 5 As shown, as an embodiment, a first stator slot 126 is formed between two adjacent first tooth portions 122, and a second stator slot 127 is formed between two adjacent second tooth portions 123. Each first stator slot 126 and a second stator slot 127 cooperate to form a winding slot 128 for accommodating an annular winding 125. One end of the second tooth portion 123 away from the yoke portion 121 is a notch end 1231, and both sides of the notch end 1231 along the circumference of the yoke portion 121 extend along the circumference of the yoke portion 121, so that the second tooth portion 123 is a "T"-shaped structure. Through the above-mentioned arrangement, the second tooth portion 123 is arranged as a "T"-shaped structure, which can increase the contact area with the housing 11, thereby facilitating the discharge of excess heat in the permanent magnet motor 100 to the outside through the housing 11; it is also beneficial to improve the firmness of the second tooth portion 123 when installed with the housing 11. At the same time, the second tooth portion 123 is a “T”-shaped structure, which can also prevent the annular winding 125 inserted in the second stator slot 127 from directly contacting the housing 11 , thereby preventing excessive wear of the annular winding 125 and extending the service life of the annular winding 125 .

[0074] As an embodiment, the first tooth portion 122 and the second tooth portion 123 both extend radially along the yoke 121, and a first protrusion structure 1221 is formed on the surface of each first tooth portion 122 close to the yoke 121, and a plurality of first groove structures 1211 and a plurality of second protrusion structures 1212 are respectively provided at both ends of the yoke 121 along its radial direction, and a second groove structure 1232 is formed on the surface of each second tooth portion 123 close to the yoke 121, and each first protrusion structure 1221 is clamped and fixed to a first groove structure 1211, and each second protrusion structure 1212 is clamped and fixed to a second groove structure 1232.

[0075] Through the above arrangement, the first tooth portion 122 and the second tooth portion 123 can be conveniently engaged and positioned with the yoke portion 121, thereby improving the convenience of connection between the first tooth portion 122, the second tooth portion 123 and the yoke portion 121. At the same time, the contact area when the first tooth portion 122 and the second tooth portion 123 are connected to the yoke portion 121 can also be increased, thereby improving the tightness when the first tooth portion 122 and the second tooth portion 123 are connected to the yoke portion 121, so as to improve the structural strength of the permanent magnet motor 100.

[0076] As an embodiment, a plurality of cooling holes 1213 for cooling the yoke 121 and / or the annular winding 125 are provided on the yoke 121, and each cooling hole 1213 is provided along the axial direction of the yoke 121 and penetrates the yoke 121; each cooling hole 1213 corresponds to a first tooth portion 122 and a second tooth portion 123 along the radial direction of the yoke 121. Through the above arrangement, after the permanent magnet motor 100 generates heat during operation, the excess heat in the permanent magnet motor 100 can be transferred to the outside through the cooling holes 1213, thereby maintaining the temperature stability of the permanent magnet motor 100 during operation, and further extending the service life of the permanent magnet motor 100.

[0077] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. A permanent magnet motor, characterized in that: include: case; A stator, the stator comprising: A yoke, wherein the yoke is made of a first material and is in a ring shape; A plurality of first teeth, wherein the first teeth are made of the first material, and the plurality of first teeth are installed on the inner diameter surface of the yoke along the circumference of the yoke and fixed to the housing; a plurality of second tooth portions, wherein the second tooth portions are made of a second material, and the plurality of second tooth portions are mounted on the outer diameter surface of the yoke portion along the circumferential direction of the yoke portion, and each second tooth portion corresponds to one first tooth portion along the radial direction of the yoke portion, so that each second tooth portion cooperates with a corresponding first tooth portion to form a stator tooth portion; A plurality of annular windings, each of which is sleeved on the yoke, and one annular winding is arranged between two adjacent stator teeth; A rotor, the rotor being surrounded by a plurality of the first teeth, the rotor being rotatably connected to the housing so that the rotor can rotate relative to the stator, the rotor comprising: A shaft assembly, wherein an annular groove is formed on the shaft assembly, and an opening of the annular groove is located on an outer surface of the shaft assembly; A plurality of permanent magnets, wherein the plurality of permanent magnets are in a fan-shaped ring shape and are distributed in the annular groove along the circumference of the rotating shaft assembly; a first sheath, wherein the first sheath is wound around the plurality of permanent magnets, and the first sheath is made of an amorphous alloy; A second sheath is sleeved on the first sheath and is interference fit with the first sheath.

2. The permanent magnet motor according to claim 1, characterized in that: The second sheath is made of carbon fiber material.

3. The permanent magnet motor according to claim 1, characterized in that: The rotating shaft assembly comprises: A first rotating shaft, wherein a mounting groove is formed in the first rotating shaft, and the first rotating shaft is provided with the annular groove, wherein an opening of the annular groove is located on an outer surface of the first rotating shaft; A second rotating shaft, wherein the second rotating shaft is at least partially located in the mounting groove and fixed to the mounting groove.

4. The permanent magnet motor according to claim 1, characterized in that: The annular groove is consistent with the permanent magnet in length along the axial direction of the first rotating shaft; The lengths of the first sleeve and the second sleeve along the axial direction of the first rotating shaft are greater than the length of the annular groove along the axial direction of the first rotating shaft.

5. The permanent magnet motor according to claim 4, characterized in that: The second rotating shaft is provided with a plurality of weight-reducing grooves, which are evenly distributed on the outer diameter surface of the second rotating shaft along the circumference of the second rotating shaft, and the openings of the plurality of weight-reducing grooves face the first rotating shaft.

6. The permanent magnet motor according to claim 4, characterized in that: The first rotating shaft is defined as having two ends along its axial direction as a first section and a second section respectively, the length of the first section along the axial direction of the first rotating shaft is consistent with the length of the second section along the axial direction of the first rotating shaft; the volume of the first section is greater than the volume of the second section; Or the first section is provided with an extension piece for increasing the volume of the first section, and the extension piece is fixed on the first section or is integrally formed with the first section.

7. The permanent magnet motor according to claim 1, characterized in that: The first material is an amorphous alloy, and the second material is a soft magnetic composite material.

8. The permanent magnet motor according to claim 7, characterized in that: A first stator slot is formed between two adjacent first tooth portions, a second stator slot is formed between two adjacent second tooth portions, and each of the first stator slots and one of the second stator slots cooperate to form a winding slot for accommodating one of the annular windings; One end of the second tooth portion away from the yoke portion is a notch end, and both sides of the notch end along the circumference of the yoke portion extend along the circumference of the yoke portion, so that the second tooth portion presents a "T"-shaped structure.

9. The permanent magnet motor according to claim 1, characterized in that: Both the first tooth portion and the second tooth portion extend radially along the yoke portion, a first protrusion structure is formed on the surface of each first tooth portion close to the yoke portion, a plurality of first groove structures and a plurality of second protrusion structures are respectively provided at both ends of the yoke portion along the radial direction, a second groove structure is formed on the surface of each second tooth portion close to the yoke portion, each first protrusion structure is clamped and fixed to one of the first groove structures, and each second protrusion structure is clamped and fixed to one of the second groove structures.

10. The permanent magnet motor according to claim 1, characterized in that: The yoke is provided with a plurality of cooling holes for cooling the yoke and / or the annular winding, and each of the cooling holes is arranged through the yoke along the axial direction of the yoke; Each of the cooling holes corresponds to one of the first teeth and one of the second teeth along the radial direction of the yoke.

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