Motor, rotating mirror and lidar

Abstract

This application discloses a motor, a rotating mirror, and a lidar. The motor includes a housing, a rotating shaft, a magnet, and a coil. The housing includes a magnetically conductive cylinder, a magnetically conductive cover, and a magnetically conductive carrier plate. The magnetically conductive cylinder has a first port and a second port. The magnetically conductive cover covers the first port and is connected to the magnetically conductive cylinder. The magnetically conductive carrier plate covers the second port and is connected to the magnetically conductive cylinder. The magnetically conductive cylinder, magnetically conductive cover, and magnetically conductive carrier plate together form an electromagnetic shielding cavity. The rotating shaft passes through the housing. The magnet is fixed relative to one of the housing and the rotating shaft, and the coil is fixed relative to the other. In this embodiment, the magnetically conductive cylinder, magnetically conductive cover, and magnetically conductive carrier plate in the housing are all magnetically conductive and together form an electromagnetic shielding cavity. That is, the housing forms a roughly continuous magnetic circuit, so that the alternating magnetic field generated during motor operation can be more confined within the housing, reducing magnetic resistance and minimizing magnetic leakage. By designing the housing to be magnetically conductive and enclosing an electromagnetic shielding cavity, the overall volume does not increase due to shielding requirements, thus adapting to miniaturization needs.

Description

Technical Field

[0001] This application relates to the field of electrical equipment technology, and in particular to an electric motor, a rotating mirror, and a lidar. Background Technology

[0002] Electric motors (such as micro motors) are widely used in automobiles, medical equipment, drones and other fields. When the motor is running, it generates an alternating magnetic field. The alternating magnetic field is prone to leakage through the air, which can lead to electromagnetic interference exceeding the standard.

[0003] In related technologies, metal shielding covers are designed for electromagnetic shielding. However, metal shielding covers have drawbacks such as large size, heavy weight, and complex assembly, and are difficult to adapt to miniaturization requirements. Utility Model Content

[0004] This application provides a motor, a rotating mirror, and a lidar to improve the problems of large size, heavy weight, complex assembly, and difficulty in adapting to miniaturization requirements of metal shielding covers in related technologies.

[0005] This application provides an embodiment of a motor, including: The housing includes a magnetic cylinder, a magnetic cover, and a magnetic carrier plate. The magnetic cylinder has a first port and a second port. The magnetic cover covers the first port and is connected to the magnetic cylinder. The magnetic carrier plate covers the second port and is connected to the magnetic cylinder. The magnetic cylinder, the magnetic cover, and the magnetic carrier plate together form an electromagnetic shielding cavity. A rotating shaft passes through the housing, with one end located in the electromagnetic shielding cavity and the other end located outside the housing; A magnet, located in the electromagnetic shielding cavity and fixed relative to one of the housing and the rotating shaft; and, The coil is located in the electromagnetic shielding cavity and is fixed relative to the other of the housing and the rotating shaft.

[0006] In some embodiments, the relative permeability μ_r of the magnetic cylinder satisfies: μ_r≥2000.

[0007] In some embodiments, the wall thickness h1 of the magnetic cylinder satisfies: 0.5mm≤h1≤2.5mm.

[0008] In some embodiments, the magnetic cylinder comprises at least one of a permalloy component, a ferrite component, and a low-carbon steel component.

[0009] In some embodiments, the magnetic cylinder is welded to the magnetic cover, and the magnetic cylinder is welded to the magnetic carrier plate.

[0010] In some embodiments, the magnetic cover includes at least one of a low-carbon steel component and a tinplate component, and the magnetic cylinder and the magnetic cover are connected by argon arc welding.

[0011] In some embodiments, the magnetic carrier plate includes a stainless steel component, and the magnetic cylinder is laser-welded to the magnetic carrier plate.

[0012] In some embodiments, the magnet is fixed relative to the rotating shaft, the coil is fixed relative to the magnetic cylinder, and when viewed along the axial direction of the rotating shaft, the coil is located between the magnet and the magnetic cylinder; Viewed along the axial direction of the rotating shaft, the interval h2 between the magnet and the magnetic cylinder satisfies: 0.2mm≤h2≤1mm.

[0013] In some embodiments, the magnetic cover includes: A magnetic end plate, covering the first port, wherein the middle portion of the magnetic end plate bulges away from the magnetic carrier plate; and, A magnetically conductive cover plate is disposed around the magnetically conductive cylinder and connected to the magnetically conductive end plate.

[0014] In some embodiments, the magnetic carrier plate includes: A magnetically conductive substrate, which shields the second port and is connected to the magnetically conductive cylinder; and... A limiting member is located on the side of the magnetic conductive substrate away from the magnetic conductive cylinder, and has two limiting portions spaced circumferentially along the rotating shaft, the two limiting portions constraining the stroke of a rotating member fixed relative to the rotating shaft.

[0015] In some embodiments, it also includes: A metal magnetic mesh is located in the electromagnetic shielding cavity and fixed relative to the magnetic cover; the metal magnetic mesh is connected to the magnetic cylinder.

[0016] This application provides a rotating mirror, including the aforementioned motor and rotating component, which are fixed relative to the rotating shaft.

[0017] This application provides a lidar, including a transmitting component for emitting a detection beam; a receiving component for receiving an echo beam; and a rotating mirror, wherein the rotating mirror is located on the transmission path of the detection beam and is used to receive the detection beam emitted by the transmitting component and transmit it to a target object outside the lidar, and the rotating mirror is located on the transmission path of the echo beam and is used to receive the echo beam reflected back by the target object and transmit it to the receiving component.

[0018] The motor, rotating mirror, and lidar of this application embodiment are designed with a housing including a magnetic cylinder, a magnetic cover, and a magnetic carrier plate. The magnetic cylinder, magnetic cover, and magnetic carrier plate are all magnetic and together form an electromagnetic shielding cavity. That is, the housing forms a roughly continuous magnetic circuit, so that the alternating magnetic field generated by the motor during operation can be more confined within the housing, reducing magnetic resistance and reducing magnetic leakage.

[0019] The housing consists of separate magnetic cylinder, magnetic cover, and magnetic carrier plate. Compared to a one-piece design, this allows for more flexible material selection for the magnetic cylinder, magnetic cover, and magnetic carrier plate, making it easier to adapt to different parts' shape design, hardness, and other requirements.

[0020] The casing conducts magnetism and encloses an electromagnetic shielding cavity. Compared to adding an additional electromagnetic shielding structure to the motor, this design directly addresses the original structure of the motor, and the overall volume does not increase due to shielding requirements, thus meeting miniaturization needs. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 These are schematic diagrams of the rotating mirror structure provided in some embodiments of this application; Figure 2 This is a cross-sectional structural schematic diagram of a rotating mirror provided in some embodiments of this application; Figure 3 This is an exploded structural diagram of a rotating mirror provided in some embodiments of this application; Figure 4 These are schematic diagrams of the motor structure provided in some embodiments of this application; Figure 5 This is a cross-sectional structural schematic diagram of the motor provided in some embodiments of this application; Figure 6 This is an exploded structural diagram of an electric motor provided in some embodiments of this application; Figure 7 This is a graph showing the change in magnetic field strength with the driving frequency of the motor when a metal shield is used for magnetic field shielding in related technologies. Figure 8 It is a graph showing the change of magnetic field strength with the driving frequency of the motor when the housing of this application is used for magnetic field shielding; Figure 9 This is a simulation diagram of the magnetic field line distribution when a metal shield is used for magnetic field shielding in related technologies. Figure 10This is a simulation diagram of the magnetic field line distribution when the casing of this application is used for magnetic field shielding.

[0023] Explanation of reference numerals in the attached figures: 1. Motor; 2. Rotating mirror; 3. Rotating component; 301. Protrusion; 10. Housing; 101. Electromagnetic shielding cavity; 11. Magnetic tube; 111. First port; 112. Second port; 12. Magnetic cover; 121. Magnetic end plate; 122. Magnetic shield; 13. Magnetic carrier plate; 131. Magnetic substrate; 132. Limiting component; 1321. Limiting part; 20. Shaft; 30. Magnet; 40. Coil. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0025] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0026] Please see Figures 1 to 3 This application provides a lidar, which includes a transmitting component, a receiving component, and a rotating mirror 2. The transmitting component emits a detection beam, the receiving component receives an echo beam, and the rotating mirror 2 is located on the transmission path of the detection beam. It is used to receive the detection beam emitted by the transmitting component and transmit it to a target object outside the lidar. The rotating mirror 2 is also located on the transmission path of the echo beam and is used to receive the echo beam reflected back by the target object and transmit it to the receiving component.

[0027] The rotating mirror 2 includes a motor 1 and a rotating component 3. The motor 1 includes a rotating shaft 20, and the rotating component 3 is fixed relative to the rotating shaft 20. When the motor 1 is working, the rotating shaft 20 rotates, which in turn drives the rotating component 3 to rotate, thereby changing the transmission direction of the detection beam and the echo beam and improving the detection field of view of the lidar 1.

[0028] The rotating component 3 includes a reflective surface, which is used to reflect the detection beam and the echo beam. Driven by the rotating shaft 20, the reflective surface can reflect the detection beam to different fields of view and receive the echo beams reflected back from different fields of view, thereby improving the detection field of view of the lidar 1.

[0029] In some embodiments, the motor 1 drives the rotating shaft 20 to rotate 360°, thereby realizing the 360° rotation of the rotating component 3. In this case, the rotating component 3 may include multiple reflective surfaces distributed around the rotation axis, the multiple reflective surfaces being connected in a ring shape, and adjacent reflective surfaces being arranged at an angle. Thus, driven by the rotating shaft 20, the multiple reflective surfaces will sequentially be positioned on the transmission paths of the detection beam and the echo beam.

[0030] In other embodiments, the motor 1 drives the rotating shaft 20 to swing, thereby causing the rotating component 3 to swing. In this case, the rotating component 3 may include multiple reflecting surfaces distributed around the rotation axis, with adjacent reflecting surfaces arranged at an angle; the rotating component 3 may also include a single reflecting surface. If the rotating component 3 includes multiple reflecting surfaces, these surfaces can be connected sequentially but not in a ring shape. Under the drive of the rotating shaft 20, the multiple reflecting surfaces can be sequentially positioned on the transmission paths of the detection beam and the echo beam. If the rotating component 3 includes multiple reflecting surfaces, these surfaces can also be connected sequentially in a ring shape. Under the drive of the rotating shaft 20, some of the reflecting surfaces are positioned on the transmission paths of the detection beam and the echo beam. If the rotating component 3 includes a single reflecting surface, the rotation angle of the rotating shaft 20 is less than or equal to the central angle corresponding to that reflecting surface.

[0031] In this embodiment of the application, the motor 1 drives the rotating shaft 20 to swing. The motor 1 includes a limiting member 132. The limiting member 132 has two limiting portions 1321 spaced circumferentially along the rotating shaft 20. The two limiting portions 1321 are used to constrain the stroke of the rotating member 3 which is fixed relative to the rotating shaft 20.

[0032] In some embodiments, the limiting part 1321 is a limiting boss, and the outer surface of the limiting boss is used to constrain the stroke of the rotating member 3 which is fixed relative to the rotating shaft 20.

[0033] In other embodiments, the limiting member 132 includes a limiting groove, and the two limiting portions 1321 are two inner sidewalls of the limiting groove spaced circumferentially along the rotating shaft 20. The two inner sidewalls are used to constrain the stroke of the rotating member 3 fixed relative to the rotating shaft 20.

[0034] The rotating component 3 is provided with a protrusion 301. When the motor 1 is working, the rotating shaft 20 rotates, which in turn drives the rotating component 3 to rotate. During the rotation of the rotating component 3, the protrusion 301 is constrained by two limiting parts 1321, thereby constraining the rotation stroke of the rotating component 3.

[0035] Next, see Figures 4 to 6 Further explanation is given regarding motor 1.

[0036] The motor 1 includes a housing 10, a shaft 20, a magnet 30, and a coil 40. The housing 10 includes a magnetic cylinder 11, a magnetic cover 12, and a magnetic carrier plate 13. The magnetic cylinder 11 has a first port 111 and a second port 112. The magnetic cover 12 covers the first port 111 and is connected to the magnetic cylinder 11. The magnetic carrier plate 13 covers the second port 112 and is connected to the magnetic cylinder 11. The magnetic cylinder 11, magnetic cover 12, and magnetic carrier plate 13 together form an electromagnetic shielding cavity 101. The shaft 20 passes through the housing 10, with one end located in the electromagnetic shielding cavity 101 and the other end outside the housing 10. The magnet 30 is located in the electromagnetic shielding cavity 101 and fixed relative to either the housing 10 or the shaft 20. The coil 40 is located in the electromagnetic shielding cavity 101 and fixed relative to the other of the housing 10 and the shaft 20.

[0037] The housing 10 includes a magnetic cylinder 11, a magnetic cover 12, and a magnetic carrier plate 13. The magnetic cylinder 11, the magnetic cover 12, and the magnetic carrier plate 13 are all magnetic and together form an electromagnetic shielding cavity 101. That is, the housing 10 forms a roughly continuous magnetic circuit, so that the alternating magnetic field generated by the motor 1 during operation can be more confined within the housing 10, reducing magnetic resistance and reducing magnetic leakage.

[0038] The housing 10 includes a separate magnetic cylinder 11, a magnetic cover 12, and a magnetic carrier plate 13. Compared with an integrated design, the magnetic cylinder 11, magnetic cover 12, and magnetic carrier plate 13 are more flexible in terms of material selection and are more conducive to adapting to the shape design, hardness and other requirements of different parts.

[0039] The housing 10 conducts magnetism and encloses to form an electromagnetic shielding cavity 101. Compared with adding an electromagnetic shielding structure to the motor, the original structure of the motor 1 is designed directly, and the overall volume will not increase due to the shielding requirements, thus adapting to the miniaturization requirements.

[0040] The magnetic cylinder 11 is welded to the magnetic cover 12, and the magnetic cylinder 11 is also welded to the magnetic carrier plate 13. The magnetic cylinder 11, the magnetic cover 12, and the magnetic carrier plate 13 form a continuous magnetic circuit through welding.

[0041] The relative permeability μ_r of the magnetic cylinder 11 satisfies: μ_r ≥ 2000. By reasonably limiting the relative permeability of the magnetic cylinder 11, it can respond quickly and effectively conduct magnetic flux even under weak magnetic fields, significantly reducing electromagnetic interference. In some embodiments, 2000 ≤ μ_r ≤ 4000. In this case, the magnetic cylinder 11 can be made of a lower-cost magnetic material, such as ferrite. Optionally, μ_r can be 2000, 2500, 3000, 3500, 4000, etc. In other embodiments, μ_r ≥ 4000. In this case, the magnetic cylinder 11 can be made of a magnetic material with higher permeability, such as permalloy. Optionally, μ_r can be 4000, 4500, 5000, 5500, 6000, etc.

[0042] The magnetic cylinder 11 includes at least one of permalloy, ferrite, and low-carbon steel components, which can be flexibly selected according to actual needs.

[0043] The wall thickness h1 of the magnetic cylinder 11 satisfies: 0.5mm ≤ h1 ≤ 2.5mm. By reasonably limiting the wall thickness of the magnetic cylinder 11, the magnetic permeability and mechanical strength of the magnetic cylinder 11 can be better balanced. Optionally, h1 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, etc.

[0044] Along the axial direction of the rotating shaft 20, the projection of the magnetic cylinder 11 is roughly circular.

[0045] The magnetic cover 12 includes a magnetic end plate 121 and a magnetic shield 122. The magnetic end plate 121 covers the first port 111, and the magnetic shield 122 is disposed around the magnetic cylinder 11 and connected to the magnetic end plate 121. When connecting the magnetic cover 12 to the magnetic cylinder 11, the magnetic cover 12 can be placed on the magnetic cylinder 11 first to achieve pre-fixation of the magnetic cover 12 and the magnetic cylinder 11, which facilitates subsequent connection and fixation between the two by welding or other methods.

[0046] The magnetic end plate 121 and the magnetic cover plate 122 can be an integral structure, which improves the structural stability of the magnetic cover 12 and reduces the assembly steps.

[0047] The middle part of the magnetic end plate 121 bulges away from the magnetic carrier plate 13.

[0048] The magnetic cover 12 includes a magnetic end plate 121 and a magnetic cover plate 122. The magnetic end plate 121 has a raised center, meaning that the magnetic cover 12 is not a smooth structure. It has shape requirements and certain processing difficulties, so there are requirements for material selection.

[0049] The magnetic cover 12 comprises at least one of a low-carbon steel component and a tinplate component. The low-carbon steel component and the tinplate component meet the shape requirements of the magnetic cover 12 and have good relative magnetic permeability, which helps reduce electromagnetic interference. The thickness of the tinplate component can be approximately 0.5 mm.

[0050] The magnetic cylinder 11 and the magnetic cover 12 are connected by argon arc welding. The argon arc welding connection ensures the continuity of magnetic permeability at the connection between the magnetic cylinder 11 and the magnetic cover 12.

[0051] The magnetic carrier plate 13 includes a magnetic substrate 131 and a limiting member 132. The magnetic substrate 131 blocks the second port 112 and is connected to the magnetic cylinder 11. The limiting member 132 is located on the side of the magnetic substrate 131 away from the magnetic cylinder 11, and has two limiting portions 1321 spaced circumferentially along the rotation axis 20. The two limiting portions 1321 are used to constrain the stroke of the rotating member 3, which is fixed relative to the rotation axis 20. The magnetic substrate 131 can be connected to the magnetic cylinder 11 by welding.

[0052] The magnetic substrate 131 and the limiting member 132 can be an integral structure, which improves the structural stability of the magnetic carrier plate 13 and reduces assembly steps.

[0053] The magnetic carrier plate 13 includes a magnetic substrate 131 and a limiting member 132. That is, the magnetic carrier plate 13 is not a smooth structure, but has shape requirements and certain processing difficulties. Therefore, there are requirements for material selection.

[0054] The magnetic carrier plate 13 includes stainless steel components. The stainless steel components can meet the shape requirements of the magnetic carrier plate 13 and have better relative permeability, which helps to reduce electromagnetic interference.

[0055] The magnetic cylinder 11 and the magnetic carrier plate 13 are connected by laser welding. The weld width of the laser welding connection is less than or equal to 0.2 mm, which can ensure the continuity of magnetic permeability at the connection between the magnetic cylinder 11 and the magnetic carrier plate 13.

[0056] In some embodiments, the magnetic cover 12 and the magnetic carrier plate 13 are made of metal, for example, the magnetic cover 12 is made of low-carbon steel, the magnetic carrier plate 13 is made of stainless steel, and the magnetic cylinder 11 is made of permalloy or ferrite, or other high-permeability materials. The magnetic cylinder 11 and the magnetic carrier plate 13 are laser-welded together, and the weld width of the laser-welded connection is less than or equal to 0.2 mm, forming an upward-converging magnetic field channel. The magnetic cylinder 11 and the magnetic cover 12 are argon-arc-welded together to achieve a seal between the magnetic cylinder 11 and the magnetic cover 12, blocking horizontal magnetic leakage. In this way, the housing 10 can form a roughly continuous magnetic circuit, reducing magnetic resistance and minimizing magnetic leakage.

[0057] In some embodiments, the motor 1 further includes a metal magnetic mesh, which is located in the electromagnetic shielding cavity 101 and fixed relative to the magnetic cover 12. The metal magnetic mesh is connected to the magnetic cylinder 11. The combination of the metal magnetic mesh and the housing 10 can achieve multi-level shielding, further blocking magnetic leakage gaps.

[0058] In some embodiments, the inner side of the magnetic cover 12 is provided with conductive rubber to block magnetic leakage gaps, and combined with the housing 10, it achieves multi-level shielding.

[0059] The extension direction of the rotating shaft 20 is consistent with the distribution direction of the first port 111 and the second port 112 in the magnetic cylinder 11.

[0060] The rotating shaft 20 is inserted through the magnetic carrier plate 13 so that one end is located in the electromagnetic shielding cavity 101 and the other end is located outside the housing 10.

[0061] The rotating shaft 20 can be made of a low-friction component, such as stainless steel, and there is no limitation on this.

[0062] The magnet 30 is wound approximately around the axial direction of the rotating shaft 20.

[0063] The magnet 30 can be made of neodymium iron boron, and there is no limitation on this.

[0064] The magnet 30 is fixed relative to one of the housing 10 and the rotating shaft 20, and the coil 40 is fixed relative to the other of the housing 10 and the rotating shaft 20. This can be either: the magnet 30 is fixed relative to the housing 10 and the coil 40 is fixed relative to the rotating shaft 20; or the magnet 30 is fixed relative to the rotating shaft 20 and the coil 40 is fixed relative to the housing 10.

[0065] In this embodiment, the magnet 30 is fixed relative to the rotating shaft 20, and the coil 40 is fixed relative to the magnetic cylinder 11. That is, when the rotating shaft 20 rotates, the magnet 30 rotates with the rotating shaft 20, while the coil 40 is fixed relative to the magnetic cylinder 11. Since the coil 40 needs to be wired for electrical conduction, designing it to be fixed relative to the magnetic cylinder 11 avoids the problem of wire winding compared to rotation.

[0066] When viewed along the axial direction of the rotating shaft 20, the rotating shaft 20 is located at the center of the magnet 30, suppressing the interference of the rotating shaft 20's movement on the magnetic field distribution.

[0067] Viewed along the axial direction of the rotating shaft 20, the coil 40 is located between the magnet 30 and the magnetic cylinder 11. For example, the magnet 30 is located around the rotating shaft 20, the coil 40 is located around the magnet 30, and the magnetic cylinder 11 is located around the coil 40. The magnet 30 is fixed relative to the rotating shaft 20, and the coil 40 is fixed relative to the magnetic cylinder 11. This can be achieved by fixing the magnet 30 to the rotating shaft 20 by means of bonding or other methods, and fixing the coil 40 to the magnetic cylinder 11 by means of bonding or other methods.

[0068] Viewed along the axial direction of the rotating shaft 20, the interval h2 between the magnet 30 and the magnetic cylinder 11 satisfies: 0.2mm≤h2≤1mm. By reasonably limiting the interval between the magnet 30 and the magnetic cylinder 11, it is beneficial to arrange the coil 40 between the magnet 30 and the magnetic cylinder 11, and to reduce the leakage magnetic path.

[0069] The assembly steps of the motor 1 in this embodiment include: winding the coil 40 and installing it onto the inner wall of the magnetic cylinder 11; embedding the magnet 30 into the center of the magnetic cylinder 11 and fixing the rotating shaft 20 to the axis of the magnet 30; laser welding the magnetic carrier plate 13 to the magnetic cylinder 11 and sealing the magnetic cover 12 to the magnetic cylinder 11 by argon arc welding.

[0070] In this embodiment, a roughly cylindrical magnetically permeable cylinder 11 is selected and wrapped around the coil 40 to form a closed magnetic circuit body. The inner diameter of the magnetically permeable cylinder 11 matches the coil 40, and the outer diameter can be designed according to shielding requirements. For example, the wall thickness of the magnetically permeable cylinder 11 is 0.5 mm to better balance the magnetic permeability and mechanical strength of the magnetically permeable cylinder 11.

[0071] The embodiments of this application employ a magnetic field suppression architecture designed in collaboration with a high-permeability magnetic cylinder 11, a metal magnetic cover 12, and a metal magnetic carrier plate 13. This architecture is suitable for optimizing low magnetic field radiation of micro unidirectional motors in the field of lidar.

[0072] See Figure 7 It shows a graph illustrating the variation of magnetic field strength (level, unit: dBpT) with the motor's drive frequency (frequency, unit: Hz) when a metal shield is used for magnetic field shielding in related technologies. Figure 7 It can be seen that the magnetic field strength is 81.84 dBpT at the fundamental frequency of 82 kHz, which is close to the standard value of 85.50 dBpT. At the harmonic frequency of 165 kHz, the magnetic field strength is 69.71 dBpT, which exceeds the standard value of 62.00 dBpT.

[0073] See Figure 8 It shows a graph illustrating the variation of magnetic field strength (Level, unit: dBpT) with the motor drive frequency (Frequency, unit: Hz) when the housing 10 of this application is used for magnetic field shielding. Figure 8 It can be seen that the magnetic field strength is about 55 dBpT at the fundamental frequency of 82 kHz, which is much lower than the standard value of 85.50 dBpT. At the harmonic frequency of 165 kHz, the magnetic field strength is about 42 dBpT, which is much lower than the standard value of 62.00 dBpT.

[0074] In summary, the magnetic field strength of the motor 1 in this embodiment is attenuated by about 26 dB at the fundamental frequency of 82 kHz compared to the magnetic field shielding scheme using a metal cover in related technologies, and at the harmonic frequency of 165 kHz compared to the magnetic field shielding scheme using a metal cover in related technologies, thus greatly improving the electromagnetic shielding performance.

[0075] See Figure 9 and Figure 10 ,in, Figure 9 This diagram illustrates a simulation of the magnetic field line distribution when a metal shield is used for magnetic field shielding in related technologies. Figure 10 This diagram illustrates a simulation of the magnetic field line distribution when the housing 10 of this application is used for magnetic field shielding. The closer the magnetic field is to blue, the lower the magnetic field strength; the closer it is to red, the higher the magnetic field strength. Figure 9 and Figure 10As can be seen, in the magnetic field line distribution of this application embodiment, the blue range is extremely large, the shielding effect is good, and the leakage magnetic density can be reduced to less than 5% of the original field.

[0076] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" means at least two, for example, two, three, four, etc. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0077] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. An electric motor (1), characterized in that, include: The housing (10) includes a magnetic cylinder (11), a magnetic cover (12), and a magnetic carrier plate (13). The magnetic cylinder (11) has a first port (111) and a second port (112) facing each other. The magnetic cover (12) covers the first port (111) and is connected to the magnetic cylinder (11). The magnetic carrier plate (13) covers the second port (112) and is connected to the magnetic cylinder (11). The magnetic cylinder (11), the magnetic cover (12), and the magnetic carrier plate (13) together form an electromagnetic shielding cavity (101). A rotating shaft (20) passes through the housing (10), with one end located in the electromagnetic shielding cavity (101) and the other end located outside the housing (10); A magnet (30) is located in the electromagnetic shielding cavity (101) and fixed relative to one of the housing (10) and the rotating shaft (20); and, The coil (40) is located in the electromagnetic shielding cavity (101) and fixed relative to the other of the housing (10) and the shaft (20).

2. The motor (1) according to claim 1, characterized in that, The relative permeability μ_r of the magnetic cylinder (11) satisfies: μ_r≥2000; And / or, the wall thickness h1 of the magnetic cylinder (11) satisfies: 0.5mm≤h1≤2.5mm; And / or, the magnetic cylinder (11) includes at least one of permalloy, ferrite, and low carbon steel.

3. The motor (1) according to claim 1, characterized in that, The magnetic cylinder (11) is welded to the magnetic cover (12), and the magnetic cylinder (11) is welded to the magnetic carrier plate (13).

4. The motor (1) according to claim 1, characterized in that, The magnetic cover (12) includes at least one of low carbon steel and tinplate, and the magnetic cylinder (11) and the magnetic cover (12) are connected by argon arc welding. And / or, the magnetic carrier plate (13) includes stainless steel parts, and the magnetic cylinder (11) is laser welded to the magnetic carrier plate (13).

5. The motor (1) according to claim 1, characterized in that, The magnet (30) is fixed relative to the rotating shaft (20), the coil (40) is fixed relative to the magnetic cylinder (11), and when viewed along the axial direction of the rotating shaft (20), the coil (40) is located between the magnet (30) and the magnetic cylinder (11); When viewed along the axial direction of the rotating shaft (20), the interval h2 between the magnet (30) and the magnetic cylinder (11) satisfies: 0.2mm≤h2≤1mm.

6. The motor (1) according to claim 1, characterized in that, The magnetic cover (12) includes: A magnetic end plate (121) covers the first port (111), and the middle portion of the magnetic end plate (121) protrudes in a direction away from the magnetic carrier plate (13); and, A magnetically conductive cover plate (122) is disposed on the periphery of the magnetically conductive cylinder (11) and connected to the magnetically conductive end plate (121).

7. The motor (1) according to claim 1, characterized in that, The magnetic carrier plate (13) includes: A magnetic substrate (131) shields the second port (112) and is connected to the magnetic tube (11); and, The limiting member (132) is located on the side of the magnetic substrate (131) away from the magnetic cylinder (11) and has two limiting portions (1321) spaced circumferentially along the rotating shaft (20), the two limiting portions (1321) constraining the stroke of the rotating member (3) fixed relative to the rotating shaft (20).

8. The motor (1) according to claim 1, characterized in that, Also includes: A metal magnetic mesh is located in the electromagnetic shielding cavity (101) and fixed relative to the magnetic cover (12). The metal magnetic mesh is connected to the magnetic cylinder (11).

9. A rotating mirror (2), characterized in that, include: The motor (1) according to any one of claims 1 to 8; as well as, The rotating component (3) is fixed relative to the rotating shaft (20).

10. A lidar, characterized in that, include: The transmitting component is used to emit a probe beam; A receiving component for receiving the echo beam; as well as, The rotating mirror (2) of claim 9 is located on the transmission path of the detection beam and is used to receive the detection beam emitted by the transmitting component and transmit it to the target object outside the lidar. The rotating mirror (2) is located on the transmission path of the echo beam and is used to receive the echo beam reflected back by the target object and transmit it to the receiving component.

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