Motor, swing mirror module and laser radar

Abstract

This application discloses a motor, a mirror module, and a lidar. The motor includes a housing, a shaft, a coil, and a permanent magnet. One end of the shaft extends out of a mounting hole in the housing. The coil is fixed relative to one of the housing and the shaft, and the permanent magnet is fixed relative to the other. Along the radial direction of the shaft, the permanent magnet and the coil are positioned opposite each other and spaced apart. The permanent magnet has a first surface facing the coil, which is a plane parallel to the central axis. This application design uses a plane for the first surface, which, compared to a cylindrical side surface, increases the distance between the permanent magnet and the coil. This reduces the force exerted by the permanent magnet on the coil, causing the torque value of the motor to fluctuate upwards from its lowest point, resulting in a smaller fluctuation range and more stable torque. Furthermore, the first surface can serve as a mounting reference, reducing the assembly error angle between the permanent magnet and the coil, thereby reducing torque fluctuations caused by assembly errors.

Description

Technical Field

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

[0002] Currently, large-angle scanning is achieved in lidar by using scanning mirrors. Due to the high requirements for accuracy and repeatability of lidar, high requirements are also placed on the torque fluctuation of the motor in the scanning mirror.

[0003] See related technologies. Figure 1 and Figure 2 The permanent magnet 40' inside the motor 1' of the scanning mirror is mostly cylindrical with parallel magnetization of one pair of poles. Due to the nonlinearity of its magnetic field distribution, the torque value changes with position in a curve that is roughly cosθ-shaped, and the torque value fluctuates within a large range. Utility Model Content

[0004] This application provides a motor, a mirror module, and a lidar to improve the problem in related technologies where permanent magnets often use cylindrical sides and parallel magnetization with one pair of poles. Due to the nonlinearity of their magnetic field distribution, the torque value changes with position in a curve that is roughly cosθ-shaped, resulting in a large fluctuation range in the torque value.

[0005] This application provides an embodiment of an electric motor, including a housing, a shaft, a coil, and a permanent magnet. The housing has a mounting hole extending along a first preset direction; the shaft extends along the first preset direction, with at least a portion of the shaft located in the mounting hole, and one end of the shaft extending out of the mounting hole; the coil is located in the mounting hole and is fixed relative to one of the housing and the shaft; the permanent magnet is located in the mounting hole and is fixed relative to the other of the housing and the shaft. Along the radial direction of the shaft, the permanent magnet and the coil are positioned opposite each other and spaced apart, and the coil and the permanent magnet cooperate to drive the shaft to rotate relative to the housing about the central axis of the shaft; wherein the permanent magnet has a first surface facing the coil, and the first surface is a plane parallel to the central axis.

[0006] In some embodiments, the permanent magnet is fixed relative to the shaft, the coil is fixed relative to the housing, and is arranged around the permanent magnet.

[0007] In some embodiments, the coil and the permanent magnet work together to drive the shaft to rotate about the central axis, so that the permanent magnet reciprocates between a first reversing position and a second reversing position; the first surface in the first reversing position and the first surface in the second reversing position are symmetrical about a preset plane, which is a plane passing through the central axis.

[0008] In some embodiments, the permanent magnet has an initial position, and the first surface at the initial position is symmetrical about a preset plane.

[0009] In some embodiments, a permanent magnet is sleeved on a rotating shaft, and the side of the permanent magnet includes two first surfaces that are arranged radially opposite each other along the rotating shaft.

[0010] In some embodiments, the two first surfaces are parallel.

[0011] In some embodiments, one of the first surfaces of the permanent magnet is the N pole and the other first surface is the S pole.

[0012] In some embodiments, the side of the permanent magnet also includes two opposing second surfaces, each located between two first surfaces, and the second surfaces are arc surfaces that surround the central axis and extend in the direction of the central axis.

[0013] This application embodiment also provides a swing mirror module, including the above-mentioned motor and swing mirror. The swing mirror is located outside the housing and connected to the rotating shaft. The swing mirror has a reflective surface that extends along the central axis of the rotating shaft.

[0014] This application also provides a lidar, including the aforementioned tilting mirror module.

[0015] In the motor, mirror module, and lidar of this application embodiment, the first surface of the permanent magnet facing the coil is designed to be a plane parallel to the central axis. Compared with the cylindrical side surface of the permanent magnet in related technologies, the shape of the permanent magnet has been optimized, which increases the distance between the permanent magnet on the first surface and the coil, and reduces the force exerted by the permanent magnet on the coil. This design allows the curve of the motor's torque value changing with position to rebound from the low point compared with the cosθ curve of related technologies, thus reducing the fluctuation range of the entire curve and making the torque more stable.

[0016] In addition, the first surface of the permanent magnet facing the coil is designed to be a plane parallel to the central axis. Compared with the cylindrical side surface of the permanent magnet in related technologies, this design allows the first surface to be used as the mounting reference, reducing the assembly error angle between the permanent magnet and the coil, thereby reducing torque fluctuations caused by assembly errors. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a structural diagram of the motor provided by related technologies;

[0019] Figure 2 yes Figure 1 This diagram illustrates the curve of the motor's torque value as a function of position.

[0020] Figure 3 These are schematic diagrams of the motor structure provided in some embodiments of this application;

[0021] Figure 4 yes Figure 3 A schematic diagram of the magnetic circuit structure of the motor is shown;

[0022] Figure 5 yes Figure 3 The diagram shows the curve of the motor's torque value changing with position.

[0023] Figure 6 yes Figure 3 This diagram shows the structure of the permanent magnet in the motor at the first reversal position.

[0024] Figure 7 yes Figure 3 This diagram shows the structure of the permanent magnet in the motor at the second reversal position.

[0025] Figure 8 yes Figure 3 The diagram shows the structure of the permanent magnet in the motor at the initial position, the first reversal position, and the second reversal position.

[0026] Figure 9 This is a schematic diagram of the structure of the mirror module provided in some embodiments of this application;

[0027] Figure 10 These are schematic diagrams of the structure of a lidar provided in some embodiments of this application;

[0028] Figure 11 This is a schematic diagram of the structure of the rotating mirror module provided in some embodiments of this application;

[0029] Figure 12 This is a schematic diagram of the structure of a lidar provided in some embodiments of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1', Motor; 40', Permanent magnet;

[0032] 1. Motor; 10. Housing; 11. Mounting hole; 20. Shaft; 30. Coil; 40. Permanent magnet; 41. First surface; 42. Second surface; m. Central axis; p. Preset plane;

[0033] 2. Mirror module; 3. Mirror; 301. Reflecting surface; 4. LiDAR; 5. Transmitting module; 6. Receiving module; 7. Rotating mirror; 701. Reflecting surface; 8. Rotating mirror module. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] Currently, large-angle scanning is achieved in lidar by using scanning mirrors. Due to the high requirements for accuracy and repeatability of lidar, high requirements are also placed on the torque fluctuation of the motor in the scanning mirror.

[0037] See related technologies. Figure 1 and Figure 2 The permanent magnet 40' inside the motor 1' of the scanning mirror is mostly cylindrical with parallel magnetization of one pair of poles. Due to the nonlinearity of its magnetic field distribution, the torque value changes with position in a curve that is roughly cosθ-shaped, and the torque value fluctuates within a large range.

[0038] This application optimizes the torque coefficient within the motor stroke by optimizing the side shape of the permanent magnet, resulting in smaller fluctuations and facilitating motor control. Specifically, the technical solution of this application is as follows.

[0039] Example 1

[0040] Please see Figures 3 to 10 This application provides an electric motor 1, which includes a housing 10, a rotating shaft 20, a coil 30, and a permanent magnet 40.

[0041] The housing 10 has a mounting hole 11 extending along a first preset direction. A rotating shaft 20 extends along the first preset direction, with at least a portion of the shaft 20 located within the mounting hole 11, and one end of the shaft 20 extending out of the mounting hole 11. A coil 30 is located within the mounting hole 11 and is fixed relative to one of the housing 10 and the rotating shaft 20. A permanent magnet 40 is located within the mounting hole 11 and is fixed relative to the other of the housing 10 and the rotating shaft 20. Along the radial direction of the rotating shaft 20, the permanent magnet 40 and the coil 30 are positioned opposite each other and spaced apart. The permanent magnet 40 and the coil 30 cooperate to drive the rotating shaft 20 to rotate relative to the housing 10 about its central axis m. The permanent magnet 40 has a first surface 41 facing the coil 30, and the first surface 41 is a plane parallel to the central axis m.

[0042] In the above design, the first surface 41 of the permanent magnet 40 facing the coil 30 is a plane parallel to the central axis m. Compared with the cylindrical side surface of the permanent magnet in related technologies, the shape of the permanent magnet 40 has been optimized, resulting in a greater distance between the permanent magnet 40 and the coil 30 at the first surface 41, and a smaller force exerted by the permanent magnet 40 on the coil 30. Figure 5 This design allows the torque value of motor 1 to change with position, compared to the cosθ curve of related technologies, at lower positions ( Figure 5 The upward adjustment from the 180° position shown reduces the fluctuation range of the entire change curve and makes the torque more stable.

[0043] Combination Figure 5 The experimental simulation results show that, after optimizing the magnetic field using the scheme proposed in this application, the peak-to-peak value of the torque value fluctuates by approximately 14.5% within 180°±45°, and by approximately 2% within 180°±30°, compared to... Figure 2 The torque values ​​of the related technologies shown fluctuate by about 30% within 180°±45° and about 13.4% within 180°±30°. After optimization, the torque value variation at different positions is significantly reduced, especially in the 180°±30° working area.

[0044] In addition, the first surface 41 of the permanent magnet 40 facing the coil 30 is a plane parallel to the central axis m. Compared with the cylindrical side surface of the permanent magnet in the related technology, it is advantageous to use the first surface 41 as the mounting reference, reduce the assembly error angle between the permanent magnet 40 and the coil 30, and thus reduce the torque fluctuation caused by the assembly error.

[0045] Next, see Figure 3 and Figure 4 The housing 10 is described in detail.

[0046] The housing 10 has two opposing end faces, and the mounting hole 11 can penetrate one of the two end faces. In this way, one end of the rotating shaft 20 can pass through the penetrating end face and be located outside the housing 10, while the other end of the rotating shaft 20 is constrained by the non-penetrating end face and is not easy to fall out of the housing 10. The part of the rotating shaft 20 located in the mounting hole 11 can be rotatably connected to the housing 10 through a bearing.

[0047] In some embodiments, the housing 10 primarily serves a supporting and protective function. A magnetically conductive yoke may also be provided within the mounting hole 11 of the housing 10. This yoke is made of a highly permeable material and forms part of the magnetic circuit to reduce magnetic reluctance and eddy current losses, thereby improving magnetic circuit efficiency. In other embodiments, the housing 10 and the magnetically conductive yoke may be integrated into one unit; this is not a limitation.

[0048] Next, see Figure 3 and Figure 4 The rotating shaft 20 will be described in detail.

[0049] The central axis m of the rotating shaft 20 is approximately along the first preset direction. In this way, the rotating shaft 20 will hardly sway up and down relative to the inner wall of the housing 10 during the rotation of the rotating shaft 20, and it is not easy for the structural components fixed relative to the rotating shaft 20 to collide with the inner wall of the housing 10.

[0050] The rotating shaft 20 can be roughly cylindrical, and there is no limitation on this.

[0051] Next, see Figure 4 , Figures 6 to 8 A detailed explanation of coil 30 is provided.

[0052] The coil 30 is fixed relative to the housing 10 and surrounds the permanent magnet 40. The design of the coil 30 being fixed relative to the housing 10 means that when the motor 1 is operating, the coil 30 and the housing 10 together form the stator and remain stationary. Since the coil 30 needs to be energized, and it remains stationary when the motor 1 is operating, this reduces the wiring requirements of the coil 30 and avoids problems such as winding.

[0053] The coil 30 and the permanent magnet 40 work together to drive the rotating shaft 20 to rotate relative to the housing 10 around its central axis m. Specifically, the coil 30 can be periodically energized to change the magnetic field around it, thereby driving the rotating shaft 20 to rotate relative to the housing 10 around its central axis m. For example, the permanent magnet 40 generates a constant magnetic field. When the direction of energization and / or the magnitude of the current in the coil 30 changes, a changing magnetic field is generated around the coil 30. This changing magnetic field interacts with the constant magnetic field, driving the coil 30 and the permanent magnet 40 to move relative to each other, and thus driving the rotating shaft 20 and the housing 10 to move relative to each other.

[0054] Next, see Figure 4 , Figures 6 to 8 The permanent magnet 40 is described in detail.

[0055] The permanent magnet 40 is fixed relative to the rotating shaft 20. That is, when the motor is working, the permanent magnet 40 drives the rotating shaft 20 to rotate relative to the housing 10 under the action of the magnetic field force.

[0056] The permanent magnet 40 is capable of reciprocating relative to the housing 10 in sync with the rotating shaft 20. Specifically, the coil 30 and the permanent magnet 40 work together to drive the rotating shaft 20 to rotate around the central axis m, so that the permanent magnet 40 reciprocates between a first reversing position and a second reversing position.

[0057] in, Figure 6 This diagram shows the structure of the motor 1 when the permanent magnet 40 is in the first reversal position. Figure 7This diagram shows the structure of the motor 1 when the permanent magnet 40 is in the second reversing position. The permanent magnet 40 can first move clockwise relative to the housing 10 in sync with the rotating shaft 20, so as to... Figure 6 The indicated first turning point has been moved to Figure 7 In the second reversal position shown, the permanent magnet 40 moves counterclockwise relative to the housing 10 in sync with the rotating shaft 20, so as to... Figure 7 The indicated second turning point moves to Figure 6 The first reversal position is shown in the diagram. The above two steps are repeated to achieve synchronous reciprocating swing of the permanent magnet 40 and the rotating shaft 20 relative to the housing 10.

[0058] See Figure 8 The first surface 41 at the first reversal position and the first surface 41 at the second reversal position are symmetrical about a preset plane p, which is a plane passing through the central axis m.

[0059] Furthermore, the coil 30 is symmetrical about the preset plane p. The symmetry plane of the first surface 41 of the permanent magnet 40 in the first and second folding positions is the same as the symmetry plane of the coil 30, which is beneficial to the approximate uniform distribution of the magnetic field force on the permanent magnet 40 during the oscillation process.

[0060] The permanent magnet 40 has an initial position, and its first surface 41 is symmetrical about a preset plane p in the initial position. The initial position of the permanent magnet 40 is also the position of the permanent magnet 40 before it moves. The symmetry plane of the first surface 41 in the initial position is designed to be the same as the symmetry plane of the coil 30, which is beneficial for the alignment of the permanent magnet 40 and the coil 30 during assembly in the initial position.

[0061] A permanent magnet 40 is fitted onto a rotating shaft 20. The side of the permanent magnet 40 includes two first surfaces 41, which are radially opposite to each other along the rotating shaft 20. When the motor 1 operates, the permanent magnet 40 needs to rotate synchronously relative to the housing 10 along the rotating shaft 20. The design of the permanent magnet 40 including two radially opposite first surfaces 41 along the rotating shaft 20 facilitates the balance of various parts of the permanent magnet 40 during rotation, eliminating the need for balancing steps and making it more convenient to use. Furthermore, the two opposing first surfaces 41 prevent the side of the permanent magnet 40 from becoming a rotating surface, which is more conducive to the processing and magnetization positioning of the permanent magnet 40, and also reduces the material cross-sectional area, resulting in lower costs.

[0062] Furthermore, the two first surfaces 41 are parallel, which facilitates magnetization positioning.

[0063] Furthermore, the two first surfaces 41 are symmetrical about the central axis m. This is more conducive to the balance of various parts of the permanent magnet 40 during rotation. It also helps to reduce the assembly error angle between the magnetic pole center of the permanent magnet 40 and the center of the coil 30, thereby reducing torque fluctuations caused by assembly errors.

[0064] One of the first surfaces 41 of the permanent magnet 40 is the N pole, and the other first surface 41 is the S pole. The N and S poles point in the same direction as the two surfaces. That is, the permanent magnet 40 is a single, integral permanent magnet. For example, see [reference needed]. Figure 8 The left first surface 41 of the permanent magnet 40 is the N pole and the right first surface 41 is the S pole; or, the left first surface 41 of the permanent magnet 40 is the S pole and the right first surface 41 is the N pole.

[0065] The side of the permanent magnet 40 also includes two opposing second surfaces 42, both of which are located between two first surfaces 41. The second surfaces 42 are arc surfaces that surround the central axis m and extend in the direction of the central axis m.

[0066] The permanent magnet 40 can be made of materials such as neodymium iron boron, cobalt, and ferrite, and there is no limitation on this.

[0067] See Figure 9 This application also provides a tilting mirror module 2, which includes a motor 1 and a tilting mirror 3. The tilting mirror 3 is located outside the housing 10 and connected to a rotating shaft 20. The tilting mirror 3 has a reflective surface 301, which extends along the central axis m of the rotating shaft 20. The motor 1 is used to drive the tilting mirror 3 to reciprocate around the central axis m, thereby achieving scanning of, for example, ±45° or ±60°.

[0068] See Figure 10 This application also provides a lidar 4, which is a radar system that uses laser beams to detect the position, velocity and other characteristics of a target object. Its working principle is to first emit a detection light towards the target object, and then receive the echo light reflected back by the target object. The echo light is formed by the target object reflecting the detection light. By comparing the echo light with the detection light and performing appropriate processing, relevant information about the target can be obtained, such as the target distance, azimuth, altitude, velocity, attitude and even shape.

[0069] It should be noted that the "target object" mentioned in this application refers to the object to be detected by the lidar, including but not limited to: vehicles, pedestrians, buildings and vegetation; the "detection light" mentioned in this application means the laser beam emitted by the lidar for detecting the aforementioned target object; and the "echo light" mentioned in this application means the laser beam that is reflected by the aforementioned target object and directed towards the lidar.

[0070] The lidar 4 includes a tilting mirror module 3. The reflective surface 301 of the tilting mirror module 3 is used to receive and reflect the detection light output from the transmitting module 5, so that the detection light is emitted outside the lidar 4. The motor 1 is used to drive the tilting mirror 3 to rotate around the central axis m, reflecting the detection light in different directions to achieve large-angle scanning.

[0071] In some embodiments, the reflective surface 301 of the mirror module 3 is also used to receive echo light and reflect it back to the receiving module 6. In this way, echo light from different directions can be received.

[0072] Since the lidar 4 requires high precision and repeatability, this application optimizes the shape of the permanent magnet 40 to optimize the torque coefficient of the motor 1 within its stroke, resulting in smaller fluctuations and facilitating the control of the motor 1.

[0073] Example 2

[0074] See Figure 11 and Figure 12 The difference between this embodiment and the first embodiment is that the permanent magnet 40 can rotate 360° relative to the housing 10 synchronously with the rotating shaft 20.

[0075] Motor 1 can be used in rotating mirror module 8, which includes motor 1 and rotating mirror 7. Rotating mirror 7 is located outside housing 10 and connected to rotating shaft 20. The side of rotating mirror 7 includes multiple reflective surfaces 701 parallel to the central axis m. These multiple reflective surfaces 701 are evenly distributed at angular intervals around the central axis m. Motor 1 is used to drive rotating mirror 7 to rotate a full circle around the central axis m, thereby realizing scanning within a preset angle range. Optionally, rotating mirror 7 includes a prism reflector, and a reflective film can be deposited on the side of the prism to form the aforementioned reflective surface.

[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, characterized in that, include: The housing is provided with mounting holes extending in a first preset direction; A rotating shaft extends along a first preset direction, at least a portion of the rotating shaft is located in the mounting hole, and one end of the rotating shaft extends out of the mounting hole; A coil, located in the mounting hole, is fixed relative to one of the housing and the rotating shaft; and A permanent magnet is located in the mounting hole. The permanent magnet is fixed relative to the housing and another of the rotating shafts. Along the radial direction of the rotating shaft, the permanent magnet is opposite to and spaced apart from the coil. The coil and the permanent magnet are used to cooperate to drive the rotating shaft to rotate relative to the housing about the central axis of the rotating shaft. The permanent magnet has a first surface facing the coil, and the first surface is a plane parallel to the central axis.

2. The motor according to claim 1, characterized in that, The permanent magnet is fixed relative to the rotating shaft, and the coil is fixed relative to the housing and arranged around the permanent magnet.

3. The motor according to claim 2, characterized in that, The coil and the permanent magnet work together to drive the rotating shaft to rotate around the central axis, so that the permanent magnet reciprocates between a first reversal position and a second reversal position. The first surface at the first folding position and the first surface at the second folding position are symmetrical about a preset plane, which is a plane passing through the central axis.

4. The motor according to claim 3, characterized in that, The permanent magnet has an initial position. The first surface at the initial position is symmetrical about the preset plane.

5. The motor according to any one of claims 1 to 4, characterized in that, The permanent magnet is sleeved on the rotating shaft, and the side of the permanent magnet includes two first surfaces, which are arranged opposite each other along the radial direction of the rotating shaft.

6. The motor according to claim 5, characterized in that, The two first surfaces are parallel.

7. The motor according to claim 5, characterized in that, One of the first surfaces of the permanent magnet is an N pole, and the other first surface is an S pole.

8. The motor according to claim 5, characterized in that, The side of the permanent magnet also includes two opposing second surfaces, each of which is located between two first surfaces. The second surfaces are arc surfaces that surround the central axis and extend in the direction of the central axis.

9. A mirror module, characterized in that, include: The motor according to any one of claims 1 to 8; as well as A pendulum mirror, located outside the housing and connected to the rotating shaft, has a reflective surface that extends along the central axis of the rotating shaft.

10. A lidar, characterized in that, Includes the mirror module as described in claim 9.

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