A motor with magnetic self-locking structure

Abstract

The application discloses a motor with a magnetic self-locking structure and belongs to the motor field. The motor solves the problem that self-locking force always exists and influences motor operation. The technical scheme for solving the problem comprises a shell and a rotating shaft rotatably installed on the shell. The shell is fixed with an annular first magnet arranged in a circumferential direction of the rotating shaft. The rotating shaft is fixed with a mounting disc. The mounting disc is provided with an annular second magnet arranged in a circumferential direction of the first magnet. A plurality of third magnets and a plurality of fourth magnets are alternately arranged in a circumferential direction in an annular region between the first magnet and the second magnet. The third magnet and the fourth magnet can move in a radial direction of the first magnet and are connected to the mounting disc through elastic elements respectively. The elastic elements apply elastic force to the third magnet and the fourth magnet towards the first magnet. The axis of the fourth magnet extends along a tangent of the first magnet, and the fourth magnet can rotate around its own axis. The motor realizes controllable self-locking and reduces the influence on normal operation of the motor.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and in particular to an electric motor with a magnetic self-locking structure. Background Technology

[0002] In applications such as electric lifting desks, medical care beds, and industrial lifting platforms, motors are often used to drive the load for vertical lifting or frequent start-stop operations. To ensure that the equipment can reliably maintain its current position in the event of a power outage or sudden failure, and to prevent the load from sliding uncontrollably due to gravity, the motor must have sufficient self-locking capability.

[0003] To improve self-locking performance, existing technologies often employ magnetic self-locking structures. For example, utility model patent CN223024238U discloses a motor with adjustable self-locking force, which has a first magnet on the housing and a second magnet on the shaft or rotor, arranged radially or axially at intervals, applying a continuous self-locking force to the rotor through magnetic attraction. However, this approach has a significant drawback: the attractive force between the magnets persists whether the motor is running or stationary. This means that even during normal motor rotation, the rotor must continuously overcome this magnetic resistance, increasing drive current and energy consumption, reducing system efficiency, and causing accelerated temperature rise and component wear due to additional friction and hysteresis effects. Summary of the Invention

[0004] The purpose of this invention is to provide a motor with a magnetic self-locking structure, which solves the problem that the self-locking force always exists and affects the operation of the motor in the prior art, and realizes controllable self-locking.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a motor with a magnetic self-locking structure, comprising a housing and a rotating shaft rotatably mounted on the housing, wherein a first annular magnet is fixed on the housing and arranged circumferentially around the rotating shaft, and a mounting plate is fixed on the rotating shaft, wherein a second annular magnet is arranged circumferentially around the first magnet on the mounting plate, the first magnet and the second magnet are arranged radially spaced apart, and within the annular region between the first magnet and the second magnet, a plurality of third magnets and a plurality of fourth magnets are alternately arranged circumferentially, wherein both the third magnets and the fourth magnets can move radially along the first magnet and are respectively connected to the mounting plate by elastic elements, the elastic elements applying elastic forces toward the first magnet to the third magnets and the fourth magnets, and the axis of the fourth magnet is tangential to the first magnet. The line extends, and the fourth magnet can rotate around its own axis. The fourth magnet includes two oppositely arranged N poles and S poles. By rotating, the fourth magnet can bring either the N pole or the S pole closer to the first magnet. When the rotational speed of the shaft is lower than the first rotational speed, the third magnet and the fourth magnet move radially closer to the first magnet. The fourth magnet rotates around its axis, so that both the third magnet and the fourth magnet can be magnetically attracted to the first magnet to apply a self-locking force to the shaft. When the rotational speed of the shaft is higher than the first rotational speed, the third magnet and the fourth magnet move radially away from the first magnet and closer to the second magnet. The fourth magnet rotates around its axis, so that the third magnet, the fourth magnet and the second magnet form a closed magnetic circuit, reducing the magnetic attraction to the first magnet and thus reducing the self-locking force on the shaft.

[0006] After adopting the above technical solution, the present invention has the following advantages: when the motor stops or enters the deceleration and stop process from high speed rotation, when the rotation speed of the shaft gradually decreases to below the first speed, the centrifugal force on the third magnet and the fourth magnet decreases accordingly. Under the action of the radial elastic force applied by the elastic element and the magnetic force between the magnets, the two move towards the direction of the first magnet. Meanwhile, since the fourth magnet is closer to the first magnet at this time, the magnetic force it experiences from the first magnet is greater than that from the second magnet. The first magnet experiences different forces on both sides of the radial axis, so it automatically rotates around the axis under the action of the net magnetic torque, causing its magnetic poles to tend to face the opposite poles of the first magnet. Thus, together with the third magnet, it forms a strong magnetic attraction with the first magnet, providing a large self-locking force to the shaft. This forms a non-contact damping torque opposite to the direction of rotation, which plays a role in smooth deceleration and impact suppression of the shaft, minimizing mechanical impact, vibration, or structural damage caused by sudden stops. When the shaft stops completely, the stable magnetic attraction between the multiple sets of magnets can provide a large self-locking force, which can resist the rotation tendency of the shaft caused by external loads as much as possible, achieving reliable position holding in the power-off state. When the motor rotates at high speed normally, if the shaft speed is higher than the first speed, the centrifugal force on the third and fourth magnets is greater, causing them to move radially outward to a position closer to the second magnet. At this point, because the fourth magnet is closer to the second magnet, the magnetic force from the second magnet is greater than that from the first magnet. Driven by the net magnetic torque, it rotates automatically, causing its magnetic poles to align with the opposite poles of the second magnet. This forms a low-resistivity closed magnetic circuit together with the second and third magnets. According to the principle of minimum magnetic reluctance, most of the magnetic flux will preferentially pass through this near-end loop and no longer flow through the high-resistivity air gap to the first magnet. Therefore, the net magnetic attraction to the first magnet is significantly weakened, even approaching zero, dynamically releasing the magnetic flux during operation. The self-locking resistance not only significantly reduces the drive current and energy consumption during motor operation, but also minimizes the increased temperature rise and mechanical wear caused by continuously overcoming magnetic resistance. It achieves three functions: high-speed operation with no or low resistance, buffering during deceleration, and strong self-locking in a stationary state. Furthermore, it can automatically trigger reliable self-locking without external energy in the event of power failure or sudden failure, ensuring the safe maintenance of the load position as much as possible. The entire switching process is completed autonomously and collaboratively by centrifugal force, magnetic force, and elastic force, without the need for sensors, controllers, or additional power supplies. It has a simple structure and reliable response, making it more suitable for applications with stringent requirements for power failure safety, operational stability, and durability under frequent start-stop conditions, such as electric lifting desks, medical care beds, and industrial lifting platforms.

[0007] Furthermore, both the first magnet and the second magnet are arranged with alternating N and S poles along the circumference of the axis of rotation.

[0008] Using the aforementioned technical solution, when the motor is stopped or stationary, regardless of the angular position of the shaft, the third and fourth magnets can always approach a pair of opposite poles on the first magnet, such as N pole to S pole or S pole to N pole, thus always being in a state of magnetic attraction, forming a reliable and position-independent self-locking force, ensuring that the shaft can be stably maintained in any stopping position as much as possible. When the motor rotates at high speed, the alternating magnetic fields of the N and S poles of the second magnet form a periodically changing local magnetic field direction in the circumferential direction. When the third and fourth magnets approach the second magnet during outward movement, the alternating magnetic field can actively guide the fourth magnet to rotate around its radial axis, so that its magnetic poles quickly align with the magnetic poles of the adjacent second magnet, i.e., opposite poles facing each other, thereby more efficiently constructing a low magnetic reluctance closed magnetic circuit composed of the second magnet, the fourth magnet, and the third magnet, accelerating the magnetic circuit switching speed, further weakening the magnetic coupling to the first magnet, and realizing the rapid release of self-locking resistance in the running state.

[0009] Furthermore, the first magnet and the second magnet have the same number of magnetic poles.

[0010] Using the aforementioned technical solution, when the number of poles of the first magnet and the second magnet are equal, the magnetic pole distribution of the two in the circumferential direction has the same periodicity and spatial phase structure. No matter what angle the shaft is at, the third magnet and the fourth magnet can always align opposite poles when they are close to the first magnet or the second magnet, and the magnetic force on the shaft is more stable.

[0011] Furthermore, the magnetization direction of the third magnet is circumferential, and the magnetic poles of the third magnet and the second magnet are opposite on their facing radial sides.

[0012] Using the aforementioned technical solution, if the magnetic poles on opposite sides of the third magnet and the second magnet are the same, a repulsive force will be generated. This repulsive force will offset part of the centrifugal force during operation, making it difficult for the third magnet to approach the second magnet and effectively form a closed magnetic circuit, thus failing to reduce drag. When the motor is running normally, the third magnet generates centrifugal force as it rotates with the shaft, moving towards the second magnet. Since the magnetic poles on opposite sides of the two magnets are opposite, a strong magnetic attraction will be generated. This attraction can assist the centrifugal force in overcoming the elastic force of the elastic element, allowing the third magnet to move away from the first magnet more quickly and stably. At the same time, the opposite magnetic pole arrangement allows the third magnet and the second magnet to quickly form a closed magnetic circuit, minimizing magnetic interference to the first magnet.

[0013] Furthermore, the inner contour of the third magnet is an arc centered on the outer periphery of the first magnet, and the outer contour is an arc centered on the inner periphery of the second magnet.

[0014] Using the aforementioned technical solution, since the first magnet and the second magnet are both arranged in concentric rings, the annular gap between them is a continuous arc in the circumferential direction. The inner and outer arcs of the third magnet are respectively adapted to the curvature of the outer circle of the first magnet and the inner circle of the second magnet, which effectively reduces the air gap in the magnetic circuit and suppresses magnetic leakage.

[0015] Furthermore, the mounting plate is provided with partition ribs that separate adjacent third and fourth magnets, and a movable cavity is formed between adjacent partition ribs for the third or fourth magnet to move.

[0016] The aforementioned technical solution facilitates the independent installation and positioning of each magnet, effectively isolating the radial movement of the third magnet from the radial movement and rotation of the fourth magnet, and minimizing collisions, jamming, or mutual magnetic disturbances between adjacent magnets during dynamic switching due to intersecting motion trajectories or spatial interference, thereby ensuring that the magnets move independently and smoothly when responding to centrifugal force and magnetic force.

[0017] Furthermore, the fourth magnet has a rotating shaft at both ends, the partition rib has a sliding groove along the radial direction of the rotating shaft, the rotating shaft is slidably disposed in the sliding groove, and the elastic element is disposed between the rotating shaft and the second magnet in the sliding groove.

[0018] Using the aforementioned technical solution, the rotating shafts at both ends are slidably assembled in the sliding grooves opened radially along the rotating shafts on the partition ribs. This not only constrains circumferential movement but also ensures that the radial movement trajectory is accurate and free from jamming. The elastic element is set in the sliding grooves, located between the rotating shaft and the second magnet. This not only makes the structure compact and the installation reliable but also allows for linear force application along the radial direction, so that the direction of the elastic restoring force is consistent with the direction of movement, making the extension and contraction process smoother and the response more sensitive.

[0019] Furthermore, the second magnet is provided with a slide rod arranged radially along the axis of rotation, the third magnet is slidably mounted on the slide rod, the elastic element is sleeved on the slide rod, and the two ends of the elastic element abut against the second magnet and the third magnet.

[0020] Using the aforementioned technical solution, the slide bar provides high-precision radial guidance for the third magnet, minimizing its circumferential offset, tilting, or swaying during movement, thereby ensuring that it always moves smoothly along the predetermined radial path, thus guaranteeing the magnetic pole alignment accuracy between it and the first or second magnet. Secondly, the elastic element is directly sleeved on the slide bar, with its two ends acting on the second and third magnets respectively, so that the elastic force is applied precisely along the axis of the slide bar, i.e., radially. The force transmission path is shorter and the direction is clearer, enabling the third magnet to reliably and quickly return to the self-locking position close to the first magnet when the centrifugal force decreases.

[0021] Furthermore, the housing includes an end cap, the mounting plate and the end cap are spaced apart along the axial direction of the rotating shaft, the end cap is provided with a support frame arranged along the axial direction of the rotating shaft, and the first magnet is fixedly mounted on the support frame.

[0022] By adopting the aforementioned technical solution, since the mounting plate rotates synchronously with the rotating shaft, while the end cover is a fixed component, an axial gap is maintained between the two to avoid collision or friction during rotation. Furthermore, the end cover is provided with a support frame extending axially along the rotating shaft to securely fix the first magnet in a stationary position and to make it precisely aligned radially with the second magnet mounted on the rotating mounting plate. This ensures that a stable annular magnetic field is formed between the first magnet and the second magnet, providing a reliable magnetic field basis for the magnetic circuit switching and self-locking function of the third and fourth magnets.

[0023] Furthermore, the motor also includes a stator winding, and the mounting plate includes an outer ring portion for mounting the third magnet and the fourth magnet and an inner ring portion for connecting with the rotating shaft. The inner ring portion is non-magnetic and is located axially between the first magnet and the stator winding.

[0024] By adopting the aforementioned technical solution, since the mounting plate rotates synchronously with the rotating shaft, while the end cover is a fixed component, an axial gap is maintained between the two to avoid collision or friction during rotation. Furthermore, the end cover is provided with a support frame extending axially along the rotating shaft to securely fix the first magnet in a stationary position and to make it precisely aligned radially with the second magnet mounted on the rotating mounting plate. This ensures that a stable annular magnetic field is formed between the first magnet and the second magnet, providing a reliable magnetic field basis for the magnetic circuit switching and self-locking function of the third and fourth magnets. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the structure of the motor with a magnetic self-locking structure in this invention;

[0027] Figure 2 This is a cross-sectional view of the motor with a magnetic self-locking structure in this invention;

[0028] Figure 3 This is a cross-sectional view of the motor with a magnetic self-locking structure in this invention from another perspective;

[0029] Figure 4 This is a schematic diagram of the structure in this invention that applies a self-locking force to the rotating shaft;

[0030] Figure 5 This is a schematic diagram of the structure for releasing the self-locking force applied to the rotating shaft in this invention;

[0031] Figure 6 This is a partial structural diagram of the motor with a magnetic self-locking structure in this invention;

[0032] Figure 7 This is a partial structural diagram of the motor with a magnetic self-locking structure in this invention;

[0033] Figure 8 This is a partial structural cross-sectional view of the motor with a magnetic self-locking structure in this invention;

[0034] Figure 9 This is a schematic diagram of the end cap structure in this invention;

[0035] In the diagram, 1 is the housing; 2 is the rotating shaft; 3 is the stator; 4 is the first magnet; 5 is the second magnet; 6 is the third magnet; 7 is the fourth magnet; 8 is the mounting plate; 81 is the inner ring; 82 is the outer ring; 83 is the partition rib; 84 is the movable cavity; 85 is the sliding groove; 9 is the elastic element; 10 is the rotating shaft; 11 is the slide rod; 12 is the support frame; and 13 is the end cover. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0038] It should be understood that in the various embodiments of the present invention, the number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0039] It should be understood that in this invention, "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0040] It should be understood that in this invention, "multiple" refers to two or more. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, X and / or Y can represent: X alone, X and Y simultaneously, or Y alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "Contains X, Y, and Z", "Contains X, Y, and Z" means that all three X, Y, and Z are contained; "Contains X, Y, or Z" means that one of X, Y, and Z is contained; "Contains X, Y, and / or Z" means that any one, two, or three of X, Y, and Z are contained.

[0041] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The following specific embodiments may be combined or substituted with each other according to the actual situation, and the same or similar concepts or processes may not be described again in some embodiments.

[0042] like Figures 1 to 9 As shown, the present invention provides a motor with a magnetic self-locking structure, including a housing 1 and a rotating shaft 2 rotatably mounted on the housing 1. A first annular magnet 4 is fixed on the housing 1 and arranged circumferentially around the rotating shaft 2. The first magnet 4 rotatably engages with the rotating shaft 2. A mounting plate 8 is fixed on the rotating shaft 2, and a second annular magnet 5 is arranged circumferentially around the first magnet 4 on the mounting plate 8. The first magnet 4 and the second magnet 5 are arranged radially at intervals. Within the annular region between the first magnet 4 and the second magnet 5, a second annular magnet 5 is alternately arranged circumferentially. Multiple third magnets 6 and multiple fourth magnets 7 are provided. Both third magnets 6 and fourth magnets 7 can move radially along the first magnet 4 and are respectively connected to the mounting plate 8 via elastic members 9. The elastic members 9 apply an elastic force towards the first magnet 4 to the third magnets 6 and fourth magnets 7. The axis of the fourth magnet 7 extends along the tangent of the first magnet 4, and the fourth magnet 7 can rotate about its own axis. The fourth magnet 7 includes two opposing N poles and S poles. By rotating, the fourth magnet 7 can bring either the N pole or the S pole closer to the first magnet 4. Figure 4 As shown, when the rotational speed of the shaft 2 is lower than the first rotational speed, the third magnet 6 and the fourth magnet 7 move radially closer to the first magnet 4, and the fourth magnet 7 rotates around its axis, so that both the third magnet 6 and the fourth magnet 7 can be magnetically attracted to the first magnet 4, thereby applying a self-locking force to the shaft 2. Figure 5 As shown, when the rotational speed of the shaft 2 is higher than the first rotational speed, the third magnet 6 and the fourth magnet 7 move radially away from the first magnet 4 and closer to the second magnet 5. The fourth magnet 7 rotates around its axis, so that the third magnet 6, the fourth magnet 7 and the second magnet 5 form a closed magnetic circuit, reducing the magnetic attraction to the first magnet 4, thereby reducing the self-locking force on the shaft 2.

[0043] When the motor stops or enters the deceleration and stop process from high speed rotation, the rotation speed of the shaft 2 gradually decreases to below the first speed. As a result, the centrifugal force on the third magnet 6 and the fourth magnet 7 decreases. Under the action of the radial elastic force applied by the elastic element 9 and the magnetic force between the magnets, the two move towards the direction of the first magnet 4. Meanwhile, since the fourth magnet 7 is closer to the first magnet 4 at this time, the magnetic force it receives from the first magnet 4 is greater than that from the second magnet 5. The forces on the two radial sides of the first magnet 4 are different, so under the action of the net magnetic torque, it automatically rotates around the axis, causing its magnetic poles to tend to be opposite to the first magnet 4. Thus, together with the third magnet 6, it forms a strong magnetic attraction with the first magnet 4, providing a large self-locking force to the rotating shaft 2. That is, it forms a non-contact damping torque opposite to the direction of rotation, which plays a role in smooth deceleration and impact suppression of the rotating shaft 2, avoiding mechanical impact, vibration or structural damage caused by sudden stop as much as possible. When the rotating shaft 2 stops completely, the stable magnetic attraction between multiple sets of magnets can provide a large self-locking force, which can resist the rotation tendency of the rotating shaft 2 caused by external load as much as possible, and achieve reliable position maintenance in the power-off state. When the motor rotates at high speed normally, if the rotational speed of shaft 2 is higher than the first rotational speed, the centrifugal force on the third magnet 6 and the fourth magnet 7 will be greater, causing them to move radially outward to a position close to the second magnet 5. At this time, because the fourth magnet 7 is closer to the second magnet 5, the magnetic force on it from the second magnet 5 is greater than the magnetic force on the first magnet 4. Thus, driven by the net magnetic torque, it will automatically rotate, causing its magnetic poles to tend to face the opposite poles of the second magnet 5. The arrow indicates the direction of the magnetic circuit. Therefore, together with the second magnet 5 and the third magnet 6, it forms a low magnetic reluctance closed magnetic circuit. According to the principle of minimum magnetic reluctance, most of the magnetic flux will preferentially pass through this near-end closed circuit and will no longer flow through the high magnetic reluctance air gap to the first magnet 4. Therefore, the net magnetic attraction force on the first magnet 4 is significantly weakened or even approaches zero. It dynamically releases the self-locking resistance during operation, which not only significantly reduces the drive current and energy consumption of the motor during operation, but also minimizes the increased temperature rise and mechanical wear caused by continuously overcoming magnetic resistance. It achieves three functions: high-speed operation with no or low resistance, buffering during deceleration, and strong self-locking in the stationary state. Moreover, it can automatically trigger reliable self-locking without external energy in the event of power failure or sudden failure, ensuring the safe maintenance of the load position as much as possible. The entire switching process is completed autonomously and collaboratively by centrifugal force, magnetic force and elastic force, without the need for sensors, controllers or additional power supplies. It has a simple structure and reliable response, making it more suitable for application scenarios with stringent requirements for power failure safety, stable operation and durability in frequent start-stop operations, such as electric lifting tables, medical care beds and industrial lifting platforms.

[0044] It should be noted that a radial gap is provided between the first magnet 4 and the rotating shaft 2. Of course, in order to improve the installation reliability of the first magnet 4, in other embodiments, the first magnet 4 can also be supported on the rotating shaft 2 by a bearing to improve its coaxiality and structural stability with the rotating shaft 2.

[0045] In this configuration, the first magnet 4 and the second magnet 5 are arranged with alternating N and S poles along the circumference of the rotating shaft 2. When the motor is stopped or stationary, regardless of the angular position of the rotating shaft 2, the third magnet 6 and the fourth magnet 7 can always approach a pair of opposite poles on the first magnet 4, such as N pole to S pole or S pole to N pole, thus always being in a state of magnetic attraction, forming a reliable and position-independent self-locking force, ensuring that the rotating shaft 2 can be stably maintained in any stopped position as much as possible. When the motor rotates at high speed, the alternating magnetic fields of the N and S poles of the second magnet 5 form a periodically changing local magnetic field direction in the circumferential direction. When the third magnet 6 and the fourth magnet 7 move outward and approach the second magnet 5, the alternating magnetic field can actively guide the fourth magnet 7 to rotate around its radial axis, so that its magnetic poles quickly align with the magnetic poles of the adjacent second magnet 5, that is, opposite poles facing each other. This more efficiently constructs a low magnetic resistance closed magnetic circuit composed of the second magnet 5, the fourth magnet 7, and the third magnet 6, speeds up the magnetic circuit switching speed, further weakens the magnetic coupling to the first magnet 4, and realizes the rapid release of self-locking resistance in the operating state.

[0046] Furthermore, the first magnet 4 and the second magnet 5 have the same number of magnetic poles, and their magnetic pole distribution in the circumferential direction has the same periodicity and spatial phase structure. No matter what angle the rotating shaft 2 is at, the third magnet 6 and the fourth magnet 7 can always align opposite poles when they are close to the first magnet 4 or the second magnet 5, making the magnetic force on the rotating shaft 2 more stable.

[0047] It should be noted that the first magnet 4 and the second magnet 5 are both toroidal magnets. The first magnet 4, the second magnet 5, the third magnet 6 and the fourth magnet 7 are made of neodymium iron boron material. The two magnets are evenly arranged with four magnetic poles along the circumference of the axis of rotation 2, that is, two pairs of N and S poles, forming a symmetrical and stable multi-pole toroidal magnetic field, which provides a reliable magnetic field basis for the magnetic circuit switching and self-locking function of the third magnet 6 and the fourth magnet 7.

[0048] The housing 1 includes an end cap 13. Since the mounting plate 8 rotates synchronously with the rotating shaft 2, while the end cap 13 is a fixed component, an axial clearance needs to be maintained between the two to avoid collision or friction during rotation. Therefore, in this application, the mounting plate 8 and the end cap 13 are spaced apart along the axial direction of the rotating shaft 2. The end cap 13 is provided with a support frame 12 arranged along the axial direction of the rotating shaft 2. The first magnet 4 is fixedly mounted on the support frame 12 and is precisely aligned radially with the second magnet 5 mounted on the rotating mounting plate 8, thereby ensuring that a stable annular magnetic field is formed between the first magnet 4 and the second magnet 5, providing a reliable magnetic field basis for the magnetic circuit switching and self-locking function of the third magnet 6 and the fourth magnet 7.

[0049] It should be noted that the end cover 13 is the axial end structure of the motor housing 1. It can be the end cover 13 on the front side of the motor or the end cover 13 on the rear side of the motor. Correspondingly, the first magnet 4 fixed on the end cover 13, as well as the second magnet 5, the third magnet 6 and the fourth magnet 7 that cooperate with it, can be flexibly set at the front or rear of the motor according to the overall layout requirements of the motor, thereby improving the structural adaptability and the flexibility of the overall integration without changing the core function of the motor.

[0050] If the magnetic poles of the third magnet 6 and the second magnet 5 are the same on opposite sides, a repulsive force will be generated. This repulsive force will offset part of the centrifugal force during operation, making it difficult for the third magnet 6 to approach the second magnet 5 and effectively form a closed magnetic circuit, thus failing to reduce drag. Therefore, in this invention, the magnetic poles of the third magnet 6 and the second magnet 5 are opposite on their radially facing sides. When the motor is running normally, the third magnet 6 generates centrifugal force as the shaft 2 rotates, moving towards the second magnet 5. Since the magnetic poles of the two opposite sides are opposite, a strong magnetic attraction will be generated. This attraction can assist the centrifugal force in overcoming the elastic force of the elastic element 9, allowing the third magnet 6 to move away from the first magnet 4 more quickly and stably. At the same time, the opposite magnetic pole arrangement allows the third magnet 6 and the second magnet 5 to quickly form a closed magnetic circuit, minimizing magnetic interference to the first magnet 4.

[0051] Since the first magnet 4 and the second magnet 5 are both arranged in concentric rings, the annular gap between them is a continuous arc in the circumferential direction. Therefore, in this invention, the inner contour of the third magnet 6 is an arc with the same center as the outer arc of the first magnet 4, and the outer contour of the third magnet 6 is an arc with the same center as the inner arc of the second magnet 5. That is, the third magnet 6 is a straight segment of a fan ring, which effectively reduces the air gap in the magnetic circuit and suppresses magnetic leakage. The magnetization direction of the third magnet 6 is circumferential, which means that one end is the N pole and the other end is the S pole, and the polarity is distributed along the arc length. When it crosses one N pole and the adjacent S pole of the second magnet 5, its two ends form opposite poles with the N pole and S pole of the second magnet 5 respectively, thereby generating an attractive force on both sides at the same time, enhancing the overall magnetic coupling force with the second magnet 5, and making the force on the third magnet 6 more balanced.

[0052] It should be noted that the magnetic poles of two adjacent third magnets 6 along the circumferential axis 2 are arranged in opposite directions. That is, if one of the third magnets 6 has an N pole at one end and an S pole at the other end (i.e., the circumferential magnetization direction is clockwise), then the circumferential magnetization direction of its adjacent third magnet 6 is counterclockwise, and the polarities of the magnetic poles at both ends are opposite. This arrangement strictly corresponds to the magnetic field of the first magnet 4 and the second magnet 5, which are arranged with alternating N and S poles along the circumferential direction. This ensures that, as far as possible, when each third magnet 6 is close to the first magnet 4 or the second magnet 5, its two circumferentially magnetized ends are respectively aligned with an adjacent N pole and an S pole on the first magnet 4 or the second magnet 5, thus forming opposite poles facing each other and generating an attractive force on both sides.

[0053] The fourth magnet 7 attracts the first magnet 4 or the second magnet 5 by rotating. In order to make the rotation of the fourth magnet 7 more stable, the fourth magnet 7 is rectangular in shape and the magnetization direction of the fourth magnet 7 is radial. This makes the effective magnetic pole area and magnetic attraction characteristics facing the first magnet 4 or the second magnet 5 remain basically consistent when it rotates around its own axis, regardless of the angle of rotation. This avoids sudden changes in magnetic force or directional sensitivity caused by rotation as much as possible, significantly reduces rotational resistance, and allows the fourth magnet 7 to rotate more freely and smoothly during the dynamic changes of centrifugal force and magnetic force. In this design, each fourth magnet 7 is positioned relative to only a single magnetic pole of the second magnet 5, and does not cross one N pole and the adjacent S pole of the second magnet 5. If the fourth magnet 7 crosses the N pole and the S pole, its two ends will be subjected to opposite magnetic forces at the same time, with one end being attracted and the other being repelled. This would cause the magnetic torques to cancel each other out or become ambiguous, which would not only weaken the flipping driving force but also cause it to remain in an unstable equilibrium position in the middle, seriously affecting the reliability and response speed of the magnetic circuit switching. By adopting a single-pole opposing design, it is possible to ensure that the fourth magnet 7 is subjected to a single, clear, and consistent magnetic torque at any position. Thus, when it is close to the first magnet 4 or the second magnet 5, only the one that is closer and has a stronger magnetic force will dominate its rotation direction, achieving rapid and deterministic polarity alignment.

[0054] Since the third magnet 6 and the fourth magnet 7 move in different ways, in order to avoid interference between their movements as much as possible, the mounting plate 8 in this invention is provided with a separating rib 83 that separates adjacent third magnet 6 and fourth magnet 7. An active cavity 84 is formed between adjacent separating ribs 83 to allow the third magnet 6 or fourth magnet 7 to move, which facilitates the independent installation and positioning of each magnet. The radial movement of the third magnet 6 is effectively isolated from the radial movement and rotation of the fourth magnet 7, so as to avoid collisions, jamming or mutual magnetic disturbances between adjacent magnets due to intersection of movement trajectories or spatial interference during dynamic switching. This ensures that the magnets move independently and smoothly when responding to centrifugal force and magnetic force.

[0055] By rationally arranging the contours and spacing of the partition ribs 83 on the mounting plate 8, the movable cavities 84 formed between adjacent partition ribs 83 exhibit differentiated geometric shapes: the movable cavity 84 corresponding to the third magnet 6 is designed as a straight segment of a fan ring, with its inner and outer arc surfaces matching the inner and outer arc contours of the third magnet 6, respectively. The side walls extend radially, thus providing the third magnet 6, which is in the shape of a straight segment of a fan ring, with a radial sliding space consistent with its shape. This limits its circumferential movement as much as possible and ensures that it moves smoothly radially under the action of elastic force and centrifugal force, thereby avoiding tilting or jamming as much as possible. The movable cavity 84 corresponding to the fourth magnet 7 is designed as a rectangular cavity, with its width matching the axial length of the fourth magnet 7. The side walls are parallel and extend radially, providing sufficient radial movement clearance for the rectangular fourth magnet 7 and leaving space for free rotation around its own radial axis, thus preventing interference with the cavity wall of the movable cavity 84 during rotation as much as possible.

[0056] It should be noted that in other embodiments, the fourth magnet 7 can also be a cylinder, which is easy to process, has low rotational resistance, and facilitates the smooth rotation of the fourth magnet 7 during motor operation.

[0057] The second magnet 5 is provided with a slide rod 11 arranged radially along the rotating shaft 2. The third magnet 6 is slidably mounted on the slide rod 11. The slide rod 11 provides high-precision radial guidance for the third magnet 6, limiting its circumferential offset, tilting or swaying during movement as much as possible, thereby ensuring that it always moves smoothly along the predetermined radial path, thus ensuring the magnetic pole alignment accuracy between it and the first magnet 4 or the second magnet 5. The elastic element 9 is sleeved on the slide rod 11, and the two ends of the elastic element 9 abut against the second magnet 5 and the third magnet 6, so that the elastic force is applied precisely along the axis of the slide rod 11, that is, radially. The force transmission path is shorter and the direction is clearer, so that the third magnet 6 can reliably and quickly return to the self-locking position close to the first magnet 4 when the centrifugal force decreases.

[0058] It should be noted that the elastic element 9 that pushes the third magnet 6 and the elastic element 9 that pushes the fourth magnet 7 are both springs.

[0059] Furthermore, the fourth magnet 7 has a rotating shaft 10 at both ends, and the partition rib 83 has a sliding groove 85 along the radial direction of the rotating shaft 2. The rotating shaft 10 is slidably disposed in the sliding groove 85, which not only constrains the circumferential movement of the fourth magnet 7, but also ensures that the radial movement trajectory is accurate and without jamming. The elastic element 9 is disposed between the rotating shaft 10 and the second magnet 5 in the sliding groove 85. It is not only compact in structure and reliable in installation, but also can apply force in a straight radial direction, so that the direction of the elastic restoring force is consistent with the direction of movement, making the extension and contraction process more stable and the response more sensitive.

[0060] The motor also includes a stator 3 and a rotor. The stator 3 is provided with stator windings. The rotor is fixed on the shaft 2 and cooperates with the stator windings to generate driving torque. The mounting plate 8 includes an outer ring portion 82 for mounting the third magnet 6 and the fourth magnet 7, and an inner ring portion 81 for connecting with the shaft 2. The inner ring portion 81 is made of non-magnetic material and is located axially between the first magnet 4 and the stator windings. This design mainly uses the non-magnetic inner ring portion 81 to effectively block the diffusion of the static magnetic field generated by the first magnet 4 to the stator winding area, significantly reducing the interference of the permanent magnet magnetic field on the winding inductance, back electromotive force and current control accuracy, avoiding electromagnetic performance fluctuations or control instability caused by magnetic circuit coupling, thereby ensuring the smooth operation and control accuracy of the motor. The mounting plate 8 has a mounting hole at its center, which is interference-fitted with the rotating shaft 2 to ensure that the mounting plate 8 can rotate synchronously with the rotating shaft 2. To further improve the reliability and torsional resistance of the connection, a pin structure, such as a positioning pin, is preferably added between the mounting hole and the rotating shaft 2. This mechanical limit prevents the mounting plate 8 from slipping relative to the rotating shaft 2 due to loosening of the interference fit under high load, frequent start-stop, or emergency stop impact conditions. This ensures the stability of torque transmission between the mounting plate 8 and the rotating shaft 2 and ensures that the third magnet 6 and the fourth magnet 7 always move synchronously with the rotating shaft 2, providing a reliable mechanical basis for the accurate response of the magnetic self-locking function.

[0061] When using, such as Figure 4As shown, when the motor is stationary, for example, taking one of the N poles of the first magnet 4, the S poles of the two third magnets 6, and the S pole of the fourth magnet 7 as an example, the N pole of the first magnet 4 is opposite to the S poles of the two third magnets 6, the S pole of the fourth magnet 7, and the N pole of the second magnet 5. The first magnet 4 is always in a state of magnetic attraction because its magnetism is opposite to that of the third magnets 6 and the fourth magnet 7, while the fourth magnet 7 is in a state of magnetic repulsion because its magnetism is the same as that of the second magnet 5. At this time, the fourth magnet 7 is also subjected to the elastic element 9. The elastic force towards the first magnet 4 causes the fourth magnet 7 to approach the first magnet 4. Although the S pole of the third magnet 6 is opposite to the N pole of the second magnet and generates a magnetic attraction, the third magnet 6 is also subject to the elastic force of the elastic member 9 towards the first magnet 4. The sum of the elastic force of the elastic member 9 and the magnetic attraction force of the first magnet 4 on the third magnet 6 is greater than the magnetic attraction force of the second magnet 5 on the third magnet 6. Therefore, the third magnet 6 approaches the first magnet 4. At this time, both the third magnet 6 and the fourth magnet 7 generate a magnetic attraction force on the first magnet 4, thereby generating a self-locking force on the rotating shaft. When the motor starts rotating, the third magnet 6 and the fourth magnet 7 rotate relative to the first magnet 4. At this time, the third magnet 6 and the fourth magnet 7 alternately face the N pole and the S pole of the first magnet 4, respectively. When the S pole of the third magnet 6 faces the N pole of the first magnet 4, the magnetic attraction force of the first magnet 4 on the third magnet 6 is opposite to the direction of the centrifugal force on the third magnet 6, and the magnetic attraction force of the second magnet 5 on the third magnet 6 is in the same direction as the centrifugal force on the third magnet 6. When the motor speed exceeds the first speed, the sum of the magnetic attraction force of the second magnet 5 on the third magnet 6 and the centrifugal force on the third magnet 6 is greater than the magnetic attraction force of the first magnet 4 on the third magnet 6. The sum of the magnetic attraction force and the elastic force of the elastic element 9 causes the third magnet 6 to move away from the first magnet 4. When the S pole of the third magnet 6 is opposite to the S pole of the first magnet 4, the direction of the repulsive force of the first magnet 4 on the third magnet 6 is the same as the direction of the centrifugal force on the third magnet 6. The direction of the magnetic attraction force of the second magnet 5 on the third magnet 6 is always the same as the direction of the centrifugal force on the third magnet 6. When the sum of the repulsive force of the first magnet 4 on the third magnet 6, the magnetic attraction force of the second magnet 5 on the third magnet 6, and the centrifugal force on the third magnet 6 is greater than the elastic force of the elastic element 9, the third magnet 6 moves away from the first magnet 4.Furthermore, at this point, when the S pole of the fourth magnet 7 is aligned with the N pole of the first magnet 4, the magnetic attraction force of the first magnet 4 on the fourth magnet 7 is opposite to the direction of the centrifugal force on the fourth magnet 7, and the repulsive force of the second magnet 5 on the fourth magnet 7 is opposite to the direction of the centrifugal force on the fourth magnet 7. When the motor speed exceeds the first speed, the centrifugal force on the fourth magnet 7 is greater than the sum of the repulsive force of the second magnet 5 on the fourth magnet 7, the magnetic attraction force of the first magnet 4 on the fourth magnet 7, and the elastic force of the elastic element 9. The fourth magnet 7 moves away from the first magnet 4. During this movement, the magnetic force of the second magnet 5 on the fourth magnet 7 is greater than the magnetic force of the first magnet 4, thus causing it to rotate automatically under the drive of the net magnetic torque, causing its magnetic poles to tend towards When the S pole of the fourth magnet 7 is opposite to the S pole of the first magnet 4, the repulsive force of the first magnet 4 on the fourth magnet 7 is in the same direction as the centrifugal force on the fourth magnet 7, while the repulsive force of the second magnet 5 on the fourth magnet 7 is opposite to the centrifugal force on the fourth magnet 7. At this time, the sum of the repulsive force of the first magnet 4 on the fourth magnet 7 and the centrifugal force on the fourth magnet 7 is greater than the sum of the repulsive force of the second magnet 5 on the fourth magnet 7 and the elastic force of the elastic element 9. The fourth magnet 7 moves away from the first magnet 4. When the repulsive forces of the first magnet 4 and the second magnet 5 on both sides of the fourth magnet 7 are different, the fourth magnet 7 rotates, so that its magnetic poles are opposite to the second magnet 5.

[0062] In addition to the preferred embodiments described above, the present invention has other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection claimed by the present invention.

Claims

1. A motor with a magnetic self-locking structure, comprising a housing and a shaft rotatably mounted on the housing, characterized in that, A first annular magnet is fixed to the housing and arranged circumferentially around a rotating shaft. A mounting plate is fixed to the rotating shaft, and a second annular magnet is arranged circumferentially around the first magnet on the mounting plate. The first and second magnets are arranged radially at intervals. In the annular region between the first and second magnets, multiple third and fourth magnets are alternately arranged circumferentially. Both the third and fourth magnets can move radially along the first magnet and are respectively connected to the mounting plate by elastic elements. The elastic elements apply an elastic force towards the first magnet to the third and fourth magnets. The axis of the fourth magnet extends along the tangent of the first magnet, and the fourth magnet can rotate about its own axis. The fourth magnet includes... Two opposing N and S poles are arranged. The fourth magnet can be rotated to bring either the N or S pole closer to the first magnet. When the rotational speed of the shaft is lower than the first rotational speed, the third and fourth magnets move radially closer to the first magnet. The fourth magnet rotates around its axis, so that both the third and fourth magnets can be magnetically attracted to the first magnet to apply a self-locking force to the shaft. When the rotational speed of the shaft is higher than the first rotational speed, the third and fourth magnets move radially away from the first magnet and closer to the second magnet. The fourth magnet rotates around its axis, so that the third, fourth, and second magnets form a closed magnetic circuit, reducing the magnetic attraction to the first magnet and thus reducing the self-locking force on the shaft.

2. The motor with a magnetic self-locking structure according to claim 1, characterized in that, Both the first and second magnets are arranged with alternating N and S poles along the circumference of the rotation axis.

3. The motor with a magnetic self-locking structure according to claim 2, characterized in that, The first magnet and the second magnet have the same number of magnetic poles.

4. The motor with a magnetic self-locking structure according to claim 2, characterized in that, The magnetization direction of the third magnet is circumferential, and the magnetic poles of the third magnet and the second magnet are opposite on their facing radial sides.

5. The motor with a magnetic self-locking structure according to claim 4, characterized in that, The inner contour of the third magnet is an arc with the same center as the outer periphery arc of the first magnet, and the outer contour of the third magnet is an arc with the same center as the inner periphery arc of the second magnet.

6. The motor with a magnetic self-locking structure according to claim 1, characterized in that, The mounting plate is provided with a partition rib that separates adjacent third and fourth magnets, and a movable cavity is formed between adjacent partition ribs for the third or fourth magnet to move.

7. The motor with a magnetic self-locking structure according to claim 6, characterized in that, The fourth magnet has a rotating shaft at both ends, the partition rib has a sliding groove along the radial direction of the rotating shaft, the rotating shaft is slidably disposed in the sliding groove, and the elastic element is disposed between the rotating shaft and the second magnet in the sliding groove.

8. The motor with a magnetic self-locking structure according to claim 1, characterized in that, The second magnet is provided with a slide bar arranged radially along the axis of rotation. The third magnet is slidably mounted on the slide bar. The elastic element is sleeved on the slide bar, and the two ends of the elastic element abut against the second magnet and the third magnet.

9. The motor with a magnetic self-locking structure according to claim 1, characterized in that, The housing includes an end cap, the mounting plate and the end cap are spaced apart along the axial direction of the rotating shaft, the end cap is provided with a support frame arranged along the axial direction of the rotating shaft, and the first magnet is fixedly mounted on the support frame.

10. The motor with a magnetic self-locking structure according to claim 1, characterized in that, The motor further includes a stator winding, and the mounting plate includes an outer ring portion for mounting the third magnet and the fourth magnet and an inner ring portion for connecting with the rotating shaft. The inner ring portion is non-magnetic and is located axially between the first magnet and the stator winding.

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