A permanent magnet synchronous motor with curved permanent magnets

Abstract

This utility model discloses a permanent magnet synchronous motor with an arc-shaped permanent magnet, belonging to the field of synchronous motor technology. It includes a fixed shaft, a stator magnetic circuit on the fixed shaft, and a rotor magnetic circuit rotating around the stator magnetic circuit outside the stator magnetic circuit. An air gap is provided between the rotor magnetic circuit and the stator magnetic circuit. The rotor magnetic circuit includes a rotor core and a permanent magnet. The rotor core is rotatably connected to the fixed shaft and is annular. The permanent magnet is fixedly connected to the inner wall of the rotor core and has a single-sided arc surface facing the stator magnetic circuit. This utility model reduces rotor torque pulsation and the amplitude of high-order harmonic components of the magnetic field generated by the permanent magnet in the stator core by using a permanent magnet with a single-sided arc surface. It also reduces the total weight of the permanent magnet by up to 30%. Furthermore, the arc shape of the permanent magnet mounted on the inner surface of the rotor core improves the cooling effect of the airflow, thus achieving more efficient cooling of the permanent magnet synchronous motor.

Description

Technical Field

[0001] This utility model belongs to the field of synchronous motor technology, and in particular relates to a permanent magnet synchronous motor with an arc-shaped permanent magnet. Background Technology

[0002] A permanent magnet synchronous motor is a type of synchronous motor that uses permanent magnets to generate a magnetic field. The rotor speed is consistent with the current frequency of the stator winding. The rotor is equipped with pre-magnetized permanent magnets, which can generate a strong magnetic field when rotating, thereby providing output torque.

[0003] However, most existing synchronous permanent magnet motors use planar permanent magnets as rotors. When used as drive devices for the wheels of electric vehicles, the amplitude of the higher harmonic components of the magnetic field is relatively high, the torque pulsation of the rotor is high, the energy efficiency of the permanent magnet synchronous motor is low, and the energy loss is high.

[0004] Therefore, there is an urgent need to design a permanent magnet synchronous motor with a curved permanent magnet to solve the problem of low energy efficiency of the synchronous permanent magnet motor mentioned above. Utility Model Content

[0005] To address the low energy efficiency of synchronous permanent magnet motors mentioned in the background art, a permanent magnet synchronous motor with an arc-shaped permanent magnet is provided to solve the aforementioned problem.

[0006] To achieve the above objectives, the specific technical solution of the permanent magnet synchronous motor with arc-shaped permanent magnets of this utility model is as follows: A permanent magnet synchronous motor with an arc-shaped permanent magnet includes a fixed shaft, a stator magnetic circuit on the fixed shaft, a rotor magnetic circuit rotating around the stator magnetic circuit outside the stator magnetic circuit, an air gap between the rotor magnetic circuit and the stator magnetic circuit, the rotor magnetic circuit including a rotor core and a permanent magnet, the rotor core being rotatably connected to the fixed shaft, the rotor core being annular, the permanent magnet being fixedly connected to the inner wall of the rotor core, and the permanent magnet having a single-sided arc surface facing the stator magnetic circuit.

[0007] Furthermore, the permanent magnet material is neodymium iron boron, and multiple permanent magnets are arranged closely on the inner wall of the rotor core, with the arc surfaces of the multiple permanent magnets all facing the stator magnetic circuit.

[0008] Furthermore, the rotor core is made of integral steel or electrical steel.

[0009] Furthermore, the arc surface is a circular arc surface, and the arc surface has a starting side and a ending side. The arc surface rises from the starting side to the highest point and then falls to the ending side. The starting side and the ending side are at the same height. When closely arranged, the ending side of the permanent magnet is connected to the starting side of the next permanent magnet. The permanent magnet also includes a bottom surface opposite the arc surface, and the permanent magnet is fixedly connected to the inner wall of the rotor core through the bottom surface.

[0010] Furthermore, the curved surface is a circular arc surface, and the radius of the circular arc surface is between R15 mm and R20 mm.

[0011] Furthermore, it also includes a housing, on which the rotor core is fixedly connected. The fixed shaft is connected to the housing via a bearing assembly, thereby allowing the rotor core to be rotatably connected to the fixed shaft. Both the stator magnetic circuit and the rotor magnetic circuit are located inside the housing to protect them.

[0012] Furthermore, the bearing assembly includes a first bearing and a second bearing, with the opposite ends of the housing fixedly connected to the outer rings of the first bearing and the second bearing, respectively, and the inner rings of both the first bearing and the second bearing fixedly connected to a fixed shaft.

[0013] Furthermore, a wire-passing hole is provided inside the fixed shaft for the electromagnetic wire to pass through, and an inlet end and an outlet end of the wire-passing hole are provided on the surface of the fixed shaft, with the first bearing located between the inlet end and the outlet end.

[0014] Furthermore, the wire-passing hole includes a first oblique hole and a second oblique hole, which are connected. The first oblique hole is connected to the inlet end, and the second oblique hole is connected to the outlet end. The included angle between the first oblique hole and the second oblique hole is greater than 100 degrees.

[0015] The permanent magnet synchronous motor with an arc-shaped permanent magnet of this invention has the following advantages: This invention reduces rotor torque pulsation and amplitude of high-order harmonic components of the magnetic field generated by the permanent magnet in the stator core by setting a permanent magnet with a single-sided arc surface. At the same time, it reduces the total weight of the permanent magnet by up to 30%. Furthermore, since the permanent magnet installed on the inner surface of the rotor core adopts an arc shape, it improves the cooling effect of airflow, thereby achieving more efficient cooling of the permanent magnet synchronous motor. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the permanent magnet synchronous motor with an arc-shaped permanent magnet of the present invention. Figure 2 This is a schematic diagram of the internal structure of the permanent magnet synchronous motor with an arc-shaped permanent magnet according to the present invention. Figure 3 This is a schematic diagram of the permanent magnet structure of this utility model; Figure 4 This is a side view of the permanent magnet of this utility model; Figure 5 This is a cross-sectional view of the permanent magnet synchronous motor with an arc-shaped permanent magnet of the present invention. Figure 6 This is a comparison diagram of the torque spectrum of a synchronous motor using a permanent magnet with an arc surface and a synchronous motor using a rectangular planar permanent magnet, based on the present invention. Figure 7 This is a comparison diagram of the magnetic losses of a synchronous motor using a permanent magnet with an arc surface and a synchronous motor using a rectangular planar permanent magnet, according to this utility model. Figure 8 This is a schematic diagram of the airflow optimization of the permanent magnet in this utility model.

[0017] The markings in the diagram are as follows: 1. Fixed shaft; 101. Wire hole; 1011. Inlet end; 1012. Outlet end; 2. Stator magnetic circuit; 201. Stator core; 202. Winding; 203. Insulating gasket; 3. Rotor magnetic circuit; 301. Rotor core; 302. Permanent magnet; 3021. Curved surface; 3022. Bottom surface; 4. Outer shell; 5. Bearing assembly; 501. First bearing; 502. Second bearing; 100. Starting side; 200. Ending side; 300. First oblique hole; 400. Second oblique hole. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0019] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0020] The following is a reference to the appendix. Figure 1 To be continued Figure 7 This invention describes a permanent magnet synchronous motor with an arc-shaped permanent magnet.

[0021] Most existing synchronous permanent magnet motors use planar permanent magnets as rotors. When used as drive devices for the wheels of electric vehicles, the amplitude of the higher harmonic components of the magnetic field is relatively high, the torque pulsation of the rotor is high, the energy efficiency of the permanent magnet synchronous motor is low, and the energy loss is high.

[0022] Therefore, this utility model provides a permanent magnet synchronous motor with an arc-shaped permanent magnet, such as... Figures 1-5As shown, the system includes a fixed shaft 1, a stator magnetic circuit 2 mounted on the fixed shaft 1, and a rotor magnetic circuit 3 rotating around the stator magnetic circuit 2. An air gap is provided between the rotor magnetic circuit 3 and the stator magnetic circuit 2. The rotor magnetic circuit 3 includes a rotor core 301 and a permanent magnet 302. The rotor core 301 is rotatably connected to the fixed shaft 1 and is annular in shape. The permanent magnet 302 is fixedly connected to the inner wall of the rotor core 301 and has a single-sided arc surface 3021 facing the stator magnetic circuit 2. Specifically, by fixing the permanent magnet 302 with the arc surface 3021 to the rotor core 301, the outer rotor magnetic circuit 3 rotates around the stator magnetic circuit 2, reducing rotor torque pulsation and decreasing the amplitude of the higher harmonic components of the magnetic field generated by the permanent magnet 302 in the stator magnetic circuit 2, thereby increasing the energy efficiency of the permanent magnet synchronous motor.

[0023] As a preferred option, such as Figure 2 As shown, multiple permanent magnets 302 are arranged closely on the inner wall of the rotor core 301. The arc surfaces 3021 of the multiple permanent magnets 302 all face the stator magnetic circuit 2, thereby increasing the effective magnetic flux density in the air gap. The high magnetic flux density can reduce the current required to achieve the same torque, reduce magnetic losses, and thus improve the efficiency of the permanent magnet synchronous motor.

[0024] Preferably, the rotor core 301 can be made of integral steel or electrical steel. In one specific embodiment, the rotor core 301 is made of electrical steel, and the permanent magnet 302 is a neodymium iron boron magnet, which is made of neodymium iron boron alloy and can generate a stronger magnetic field. At the same time, neodymium iron boron magnets have higher remanence and coercivity and are not easily affected by external magnetic fields or demagnetized.

[0025] As a preferred option, such as Figure 3 As shown, the arc surface 3021 is a circular arc surface, with a starting side 100 and a ending side 200. The arc surface 3021 rises from the starting side 100 to its highest point and then descends to the ending side 200. The starting side 100 and the ending side 200 are at the same height. When closely arranged, the ending side 200 of the permanent magnet 302 is connected to the starting side 100 of the next permanent magnet 302. The permanent magnet 302 also includes a bottom surface 3022 opposite to the arc surface 3021, and the permanent magnet 302 is fixedly connected to the inner wall of the rotor core 301 through the bottom surface 3022. Specifically, the way in which the ending side 200 of the permanent magnet 302 is connected to the starting side 100 of the next permanent magnet 302 makes the magnetization path longer, reduces magnetic leakage, and can significantly improve the magnetic flux density. At the same time, the magnetic field formed by the vertical arrangement is more uniformly distributed along the axial direction, reducing torque pulsation.

[0026] As a preferred option, such as Figure 4As shown, the arc surface 3021 is a circular arc surface. In some embodiments, the radius R of the arc surface is between 15 mm and 20 mm, reducing the mass of the permanent magnet 302 used by 30%, and optimizing the airflow generated by the rotating rotor with a specific magnet shape, such as... Figure 8 As shown, this improves the cooling effect of the motor and increases its efficiency. Understandably, compared with a normal rectangular planar permanent magnet, the permanent magnet 302 with an arc surface 3021 has a larger surface area in contact with the air, resulting in greater air resistance to the permanent magnet 302 with an arc surface 3021, thereby increasing the cooling efficiency of the airflow and enhancing the surface cooling effect of the permanent magnet 302 on the rotor core 301. Compared with a rectangular planar permanent magnet of the same specification, the weight of the permanent magnet 302 with an arc surface 3021 is reduced by about 30%, thereby reducing the force required for the stator magnetic circuit 2 to drive the rotor magnetic circuit 3, and thus increasing the energy efficiency of the permanent magnet synchronous motor.

[0027] As a preferred option, such as Figure 1 and Figure 5 As shown, it also includes a housing 4, with the rotor core 301 fixedly connected to the housing 4. The fixed shaft 1 is connected to the housing 4 through a bearing assembly 5, thereby allowing the rotor core 301 to be rotatably connected to the fixed shaft 1. The stator magnetic circuit 2 and the rotor magnetic circuit 3 are both located inside the housing 4 to protect the stator magnetic circuit 2 and the rotor magnetic circuit 3. Specifically, during the operation of the permanent magnet synchronous motor, the rotor core 301 drives the housing 4 to rotate around the fixed shaft 1.

[0028] Preferably, the bearing assembly 5 includes a first bearing 501 and a second bearing 502. The opposite ends of the housing 4 are fixedly connected to the outer rings of the first bearing 501 and the second bearing 502, respectively. The inner rings of the first bearing 501 and the second bearing 502 are both fixedly connected to the fixed shaft 1.

[0029] Preferably, the stator magnetic circuit 2 includes a stator core 201, which is fixedly connected to the fixed shaft 1. The stator core 201 is provided with a winding 202 formed by electromagnetic wire winding. Preferably, the stator core 201 is formed by stacking multiple electrical steel sheets to reduce eddy current losses. At the same time, insulating pads 203 are provided on the top and bottom surfaces of the stator core 201 to prevent current breakdown when the temperature of the stator core 201 rises.

[0030] Preferably, the fixed shaft 1 has a wire hole 101 inside for the electromagnetic wire to pass through, and the fixed shaft 1 has an inlet end 1011 and an outlet end 1012 of the wire hole 101 on its surface. The first bearing 501 is located between the inlet end 1011 and the outlet end 1012, so that the electromagnetic wire enters the housing 4 from the outside and forms a winding 202 on the stator core 201.

[0031] Preferably, the wire passage 101 includes a first oblique hole 300 and a second oblique hole 400, which are connected. The first oblique hole 300 is connected to the inlet end 1011, and the second oblique hole 400 is connected to the outlet end 1012. The included angle B between the first oblique hole 300 and the second oblique hole 400 is greater than 100 degrees, which avoids excessive bending angle of the electromagnetic wire in the wire passage 101, reduces the shearing force of the electromagnetic wire in the wire passage 101, reduces the wear of the electromagnetic wire in the wire passage 101 during use, and thus extends the service life of the device.

[0032] In one specific embodiment, the radius R of the arc surface of the permanent magnet 302 with the arc surface 3021 is 15 mm, and its mass is reduced by 30% compared to a normal rectangular planar permanent magnet. Figure 6 and Figure 7 As shown, for a rotational speed of 469 rpm, the fundamental frequency of the first harmonic is 7.8 Hz. Clearly, for higher harmonics (3rd, 5th, 7th, 9th, etc.), a synchronous motor using a permanent magnet 302 with an arc surface 3021 has advantages, specifically: according to Figure 6 A comparison of the torque spectrum of a synchronous motor using a permanent magnet 302 with an arc surface 3021 and a synchronous motor using a rectangular planar permanent magnet shows that using a permanent magnet 302 with an arc surface 3021 can reduce rotor torque pulsation and reduce the overall weight of the permanent magnet. according to Figure 7 The comparison diagram of magnetic losses between a synchronous motor using a permanent magnet 302 with an arc surface 3021 and a synchronous motor using a rectangular planar permanent magnet shows that the motor using a permanent magnet 302 with an arc surface 3021 has lower core losses.

[0033] This invention improves the electrical efficiency of an electric motor while maintaining its external dimensions and reduces the consumption of magnetic materials. The invention includes a fixed shaft 1, a stator magnetic circuit 2 fixed around the fixed shaft 1, and a rotor magnetic circuit 3 rotating around the stator magnetic circuit 2. An air gap exists between these components. The rotor magnetic circuit 3 includes a rotor core 301 and permanent magnets 302 arranged on its inner plane. A significant feature is that the permanent magnets 302 are only arc-shaped on one side. The technical effect is that, compared to motors of the same mass and size, the energy efficiency ratio of the motor is improved.

[0034] This invention reduces rotor torque pulsation and amplitude of high-order harmonic components of the magnetic field generated by the permanent magnet 302 in the stator core 201 by setting a permanent magnet 302 with a single-sided arc surface 3021, while reducing the total weight of the permanent magnet 302; furthermore, since the permanent magnet 302 installed on the inner surface of the rotor core 301 adopts an arc shape, the cooling effect of airflow is improved, thereby achieving more efficient cooling of the permanent magnet synchronous motor.

[0035] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A permanent magnet synchronous motor with an arc-shaped permanent magnet, characterized in that, It includes a fixed shaft (1), a stator magnetic circuit (2) is provided on the fixed shaft (1), and a rotor magnetic circuit (3) is provided outside the stator magnetic circuit (2) to rotate around the stator magnetic circuit (2). An air gap is provided between the rotor magnetic circuit (3) and the stator magnetic circuit (2). The rotor magnetic circuit (3) includes a rotor core (301) and a permanent magnet (302). The rotor core (301) is rotatably connected to the fixed shaft (1). The rotor core (301) is annular. The permanent magnet (302) is fixedly connected to the inner wall of the rotor core (301). The permanent magnet (302) has a single-sided arc surface (3021) facing the stator magnetic circuit (2).

2. The permanent magnet synchronous motor with an arc-shaped permanent magnet according to claim 1, characterized in that, The permanent magnet (302) is made of neodymium iron boron. Multiple permanent magnets (302) are arranged in close proximity on the inner wall of the rotor core (301). The arc surfaces (3021) of the multiple permanent magnets (302) all face the stator magnetic circuit (2).

3. The permanent magnet synchronous motor with an arc-shaped permanent magnet according to claim 1, characterized in that, The rotor core (301) is made of integral steel or electrical steel.

4. The permanent magnet synchronous motor with an arc-shaped permanent magnet according to claim 1, characterized in that, The arc surface (3021) is a circular arc surface. The arc surface (3021) has a starting side (100) and a ending side (200). The arc surface (3021) rises from the starting side (100) to the highest point and then falls to the ending side (200). The starting side (100) and the ending side (200) have the same height. When closely arranged, the ending side (200) of the permanent magnet (302) is connected to the starting side (100) of the next permanent magnet (302). The permanent magnet (302) also includes a bottom surface (3022) opposite to the arc surface (3021). The permanent magnet (302) is fixedly connected to the inner wall of the rotor core (301) through the bottom surface (3022).

5. The permanent magnet synchronous motor with an arc-shaped permanent magnet according to claim 1 or 4, characterized in that, The arc surface (3021) is a circular arc surface with a radius between R15 mm and R20 mm.

6. The permanent magnet synchronous motor with an arc-shaped permanent magnet according to claim 1, characterized in that, It also includes a housing (4), the rotor core (301) is fixedly connected to the housing (4), the fixed shaft (1) is connected to the housing (4) through a bearing assembly (5), so that the rotor core (301) is rotatably connected to the fixed shaft (1), and the stator magnetic circuit (2) and the rotor magnetic circuit (3) are both located inside the housing (4) to protect the stator magnetic circuit (2) and the rotor magnetic circuit (3).

7. The permanent magnet synchronous motor with an arc-shaped permanent magnet according to claim 6, characterized in that, The bearing assembly (5) includes a first bearing (501) and a second bearing (502). The opposite ends of the housing (4) are fixedly connected to the outer rings of the first bearing (501) and the second bearing (502), respectively. The inner rings of the first bearing (501) and the second bearing (502) are both fixedly connected to the fixed shaft (1).

8. The permanent magnet synchronous motor with an arc-shaped permanent magnet according to claim 7, characterized in that, The fixed shaft (1) has a wire hole (101) inside for the electromagnetic wire to pass through. The fixed shaft (1) has an inlet end (1011) and an outlet end (1012) of the wire hole (101) on its surface. The first bearing (501) is located between the inlet end (1011) and the outlet end (1012).

9. The permanent magnet synchronous motor with an arc-shaped permanent magnet according to claim 8, characterized in that, The wire-passing hole (101) includes a first oblique hole (300) and a second oblique hole (400), the first oblique hole (300) and the second oblique hole (400) are connected, the first oblique hole (300) is connected to the inlet end (1011), the second oblique hole (400) is connected to the outlet end (1012), and the included angle between the first oblique hole (300) and the second oblique hole (400) is greater than 100 degrees.

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