Bistable electromagnetic brake

Abstract

The invention discloses a bistable electromagnetic brake which comprises a stator connecting piece. The magnetic shell is mounted on the outer side of the stator connecting piece; the rotor connecting piece is mounted at one end of the stator connecting piece, and the rotor connecting piece is rotationally connected to the stator connecting piece; the armature is arranged between the magnetic shell and the rotor connecting piece in a sleeving manner, and the armature and the rotor connecting piece are connected through a plurality of elastic connecting pieces; a boss area between the rotor connecting piece and the armature forms a first mounting area and is provided with an inner sleeve, a first permanent magnet and an outer sleeve, a second mounting area is reserved between the sleeve and the outer sleeve, and the first permanent magnet is clamped in the second mounting area; a coil, an inner magnetic pole and a second permanent magnet are further arranged in the magnetic shell, the coil is installed in the magnetic shell, the second permanent magnet is installed at the bottom end of the inner side of the coil, a gas gap is formed between the armature and the magnetic shell, the distance of the gas gap changes along with the position of the armature relative to the magnetic shell, and the first permanent magnet and the armature form magnetic coupling. The problem that the permanent magnet is easy to break is solved.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic brake technology, specifically a bistable electromagnetic brake. Background Technology

[0002] Currently, bistable permanent magnet brakes suffer from significant technical defects. Their core component, the permanent magnet, is prone to magnetic decay under high-temperature conditions, severely impacting braking performance stability. More seriously, the traditional permanent magnet mounting method suffers from insufficient mechanical strength, increasing the risk of breakage under complex operating conditions. This not only reduces brake reliability but also limits its application in harsh environments such as high-temperature and high-vibration environments. Existing bistable permanent magnet brakes typically employ simple magnetic circuit designs, failing to effectively address the issues of high-temperature demagnetization and insufficient mechanical strength of the permanent magnet. Particularly in applications with frequent start-stop cycles or prolonged braking, permanent magnet performance degradation leads to insufficient braking force and slow response. Furthermore, the mounting method of the permanent magnet in traditional brakes often fails to adequately accommodate thermal expansion and contraction, further exacerbating the risk of permanent magnet breakage. Regarding magnetic circuit design, existing technologies lack effective magnetic circulation paths, resulting in low magnetic field utilization and slow braking response. Simultaneously, the gas gap control between the armature and the magnetic housing in traditional brakes is not precise enough, affecting the stability of the braking state. Therefore, a new bistable electromagnetic brake has become a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0003] This application provides a bistable electromagnetic brake, characterized in that it comprises: Stator connectors; A magnetic shell is installed on the outside of the stator connector, and the magnetic shell is a hollow shell; A rotor connector is installed at one end of the stator connector, the stator connector is fixed, and the rotor connector is rotatably connected to the stator connector; An armature is sleeved between the magnetic shell and the rotor connector, and the armature and the rotor connector are connected by a plurality of elastic connectors. A first mounting area is formed between the rotor connector and the boss area of ​​the armature. The first mounting area is provided with an inner sleeve, a first permanent magnet and an outer sleeve. The outer sleeve is located outside the inner sleeve. The inner sleeve and the outer sleeve are detachably connected to the rotor connector. The inner sleeve and the outer sleeve form an annular structure sleeved on the rotor connector. A second mounting area is reserved between the inner sleeve and the outer sleeve. The first permanent magnet is installed inside the second mounting area. The magnetic shell is further provided with a coil, an inner magnetic pole, and a second permanent magnet. The coil is installed inside the magnetic shell, the second permanent magnet is installed at the bottom of the inner side of the coil, and the inner magnetic pole is located at the top of the second permanent magnet. There is a gas gap between the armature and the magnetic shell. The distance of the gas gap changes with the position of the armature relative to the magnetic shell. The first permanent magnet forms a magnetic coupling with the armature. When the coil is energized, the magnetic field generated by the coil interacts with the magnetic fields of the first permanent magnet and the second permanent magnet to change the magnetic force acting on the armature, and achieves the switching between the braking state and the release state under the action of the reset force provided by the elastic connector; Furthermore, when the magnetic field generated by the first permanent magnet is activated, the magnetic force flowing between the inner sleeve, the armature, and the outer sleeve forms a circulating flow.

[0004] Optionally, a first slot is formed on one side of the inner sleeve opposite to the second mounting area; A second slot is provided on one side of the outer sleeve relative to the second mounting area; The first slot, the reserved gap between the outer sleeve and the inner sleeve together form the second mounting area, so that the first permanent magnet is snapped into the second mounting area.

[0005] Optionally, a gas gap exists between the armature and the magnetic shell, and the distance of the gas gap is set to S: When S=0, the armature and the magnetic shell are in contact; When S > 0, there is magnetic flow between the armature and the magnetic shell.

[0006] Optionally, the end face of the magnetic shell near the gas gap is the outer magnetic pole face, and the end face of the inner magnetic pole near the gas gap is the inner magnetic pole face. The inner magnetic pole face is at the same horizontal level as the outer magnetic pole face, or the inner magnetic pole face is slightly lower than the outer magnetic pole face.

[0007] Optionally, the size of the gas gap varies with the position of the armature, achieving two stable states: A) Braking state: When the armature is in contact with the outer magnetic pole surface and the inner magnetic pole surface, the gas gap S=0; And, when the armature is in contact with the outer magnetic pole surface but not with the inner magnetic pole surface, the gas gap S=0; B) Release state: When the armature is disengaged from the inner magnetic pole surface and the outer magnetic pole surface, the gas gap S=a, where a>0.

[0008] Optionally, one end of the elastic connector is connected to the rotor connector, and the other end is connected to the armature. The elastic connector provides a resetting force to the armature that moves away from the inner magnetic pole.

[0009] Optionally, the magnetization direction of the cross-section of the first permanent magnet is the annular magnetic field line formed between the inner sleeve and the outer sleeve, and the direction of the annular magnetic field line is clockwise or counterclockwise.

[0010] Optionally, when a positive current is applied to the coil, the magnetic field generated by the first permanent magnet forms a first annular magnetic field along the inner sleeve and the outer sleeve, and the magnetic field generated by the second permanent magnet forms a second annular magnetic field along the inner magnetic pole near the brake. At this time, the first annular magnetic field is in a clockwise direction, and the second annular magnetic field is in a clockwise direction.

[0011] The beneficial effects of this application are as follows: The bistable electromagnetic brake and its optimized magnetic circuit structure provided by this application, through the coordinated arrangement of magnetic shell, rotor connector, armature, inner sleeve, outer sleeve and permanent magnet, combined with the magnetic field interaction between coil and magnetic pole, form a closed magnetic circuit and realize bistable switching, which solves the problem of mechanical fracture at high temperature. It has the advantages of improving high temperature stability, reducing fracture risk, and optimizing magnetic circuit design to extend service life. Attached Figure Description

[0012] Figure 1 A schematic cross-sectional view of the bistable electromagnetic brake structure provided by the present invention; Figure 2 A schematic diagram illustrating the working principle of the bistable electromagnetic brake structure provided by the present invention; In the figure: 1. Stator connector; 2. Magnet shell; 3. Rotor connector; 4. Armature; 5. First mounting area; 6. Inner sleeve; 7. First permanent magnet; 8. Outer sleeve; 9. Second mounting area; 10. Coil; 11. Inner magnetic pole; 12. Gas gap; 13. Second permanent magnet; 14. Elastic connector. Detailed Implementation

[0013] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] In existing technologies, bistable electromagnetic brakes face risks of permanent magnet attenuation and mechanical fracture under high-temperature conditions. Traditional structures with simple magnetic circuit designs struggle to cope with thermal expansion and contraction, resulting in insufficient braking force stability. For example, in continuous operation scenarios of industrial machinery, the thermal stress generated by frequent starts and stops can cause micro-displacements between the permanent magnet and the mounting structure. Over time, this accumulation leads to changes in the magnetic circuit gap, ultimately causing demagnetization or structural failure. To address these issues, researchers discovered that the root cause of permanent magnet performance degradation lies in insufficient magnetic circuit closure and inadequate mechanical constraints. Analysis of magnetic field line distribution revealed that traditional single-circuit designs are prone to magnetic leakage at high temperatures, leading to a decrease in effective magnetic flux. Furthermore, fixed mounting structures cannot alleviate stress concentration caused by thermal deformation. Therefore, a proposed solution involves improving magnetic field stability through a split magnetic circuit design and elastic constraint structures. This utilizes a double-ring magnetic circuit to form a self-closing loop and compensates for thermal deformation through adjustable gaps. Please refer to Figures 1 to 2 As shown, this application provides a bistable electromagnetic brake, comprising: Stator connector 1, stator connector 1 is configured as a fixed and non-rotating part of the brake, stator connector 1 is configured as a bearing so that the mounting part on the outside of stator connector 1 remains fixed during operation; The magnetic shell 2 is installed on the outside of the stator connector 1. The magnetic shell 2 is a hollow shell, which is the part that is fixed and does not rotate on the outside of the bearing. The rotor connector 3 is installed at one end of the stator connector 1. The stator connector 1 is fixed and the rotor connector 3 is rotatably connected to the stator connector 1. An armature 4 is sleeved between the magnetic shell 2 and the rotor connector 3, and the armature 4 and the rotor connector 3 are connected by a plurality of elastic connectors 14. One end of the elastic connector 14 is connected to the rotor connector 3, and the other end is connected to the armature 4. The elastic connector 14 provides the armature 4 with a reset force that moves away from the inner magnetic pole 11.

[0015] The magnetic shell 2 is also provided with a coil 10, an inner magnetic pole 11 and a second permanent magnet 13. The coil 10 is installed inside the magnetic shell 2, the second permanent magnet 13 is installed at the bottom of the inner side of the coil 10, and the inner magnetic pole 11 is located at the top of the second permanent magnet 13. There is a gas gap 12 between the armature 4 and the magnetic shell 2. The distance of the gas gap 12 changes with the position of the armature 4 relative to the magnetic shell 2. The first permanent magnet 7 forms a magnetic coupling with the armature 4. Specifically, when the armature 4 moves towards the magnetic shell 2 under the action of magnetic force, the elastic connector 14 is compressed and stores elastic potential energy. When the coil 10 is de-energized or reverse-energized, the magnetic force weakens or reverses. At this time, the elastic connector 14 releases the stored potential energy, pushing the armature 4 to reset in the direction away from the inner magnetic pole 11, thereby quickly releasing the braking state. In this process, the reset force of the elastic connector 14 and the magnetic force generated by the permanent magnet complement each other, ensuring that the armature 4 can reliably switch between the two stable states. The rotor connector 3 also forms a first mounting area 5 between itself and the boss area of ​​the armature 4. The first mounting area 5 is provided with an inner sleeve 6, a first permanent magnet 7 and an outer sleeve 8. The outer sleeve 8 is located outside the inner sleeve 6. The inner sleeve 6 and the outer sleeve 8 are detachably connected to the rotor connector 3. The inner sleeve 6 and the outer sleeve 8 form an annular structure sleeved on the rotor connector 3, and a second mounting area 9 is reserved between the inner sleeve 6 and the outer sleeve 8. The first permanent magnet 7 is installed inside the second mounting area 9. In this application, the inner sleeve 6 can be configured with a magnetically conductive material of S-level (south pole) magnetic field, and the outer sleeve 8 can be configured with a magnetically conductive material of N-level (north pole) magnetic field. Specifically, when the stator connector 1 rotates, it drives the rotor connector 3 to rotate synchronously. When the coil 10 is not energized, the magnetic field of the second permanent magnet 13 causes the armature 4 to be attracted to the inner surface of the magnetic shell 2, at which time the gas gap 12 gradually decreases to achieve braking. When a reverse current is applied to the coil 10, the magnetic field it generates gradually cancels the magnetic field of the second permanent magnet 13, and the armature 4 is reset under the action of the elastic connector 14 and the first permanent magnet 7, forming the gas gap 12 to release the braking. The annular magnetic circuit formed by the first permanent magnet 7 between the inner and outer sleeves 8 effectively constrains the direction of the magnetic lines of force and reduces edge leakage. The design of the inner magnetic pole 11 surface being slightly lower than the outer magnetic pole surface ensures that the magnetic circuit remains closed when the armature 4 is disengaged, avoiding magnetic energy loss. A first slot is provided on one side of the inner sleeve 6 relative to the second mounting area 9; A second slot is provided on one side of the outer sleeve 6 relative to the second mounting area 9; The first slot, the reserved gap between the first slot and the outer sleeve 8 and the inner sleeve 6 together form the second installation area, so that the first permanent magnet 7 is snapped into the second installation area 9.

[0016] The first slot refers to a recessed structure formed on the side wall of the inner sleeve 6, which can be machined to limit the radial displacement of the first permanent magnet 7. The second slot refers to a matching recessed structure formed on the side wall of the outer sleeve 8, which can be achieved using the same machining method as the inner sleeve 6, and is used to cooperate with the first slot to fix the first permanent magnet 7. The reserved gap refers to the pre-designed assembly gap between the inner and outer sleeves 8, which can be achieved through dimensional tolerance control, to accommodate the first permanent magnet 7 and allow for thermal expansion deformation. The inner sleeve 6 and the outer sleeve 8 form a circumferential constraint on the first permanent magnet 7 through their respective slots. Combined with the axial tolerance space provided by the reserved gap, the first permanent magnet 7 can remain stably installed even under high-temperature conditions. When the first permanent magnet 7 expands due to heat, the reserved gap can absorb material deformation and avoid structural cracking caused by thermal stress concentration. The mechanical limiting effect of the slot and the deformation compensation function of the gap work together to ensure that the first permanent magnet 7 will not displace or fall off in a vibration environment. It is worth noting that this application effectively prevents the displacement and fracture of the first permanent magnet 7 in high-temperature vibration environments, improving the operational stability of the brake under harsh conditions. The slot structure eliminates the need for auxiliary fixing materials during the installation of the first permanent magnet 7, simplifying the assembly process. At the same time, the reserved gap design can adapt to material deformation under different temperature conditions, extending the service life of key components.

[0017] When the coil 10 is energized, the magnetic field generated by the coil 10 works together with the magnetic fields of the first permanent magnet 7 and the second permanent magnet 13 to change the magnetic force acting on the armature 4, and achieve the switching between the braking state and the release state under the action of the reset force provided by the elastic connector 14. Furthermore, when the magnetic field generated by the first permanent magnet 7 is generated, the magnetic force flowing between the inner sleeve 6, the armature 4 and the outer sleeve 8 forms a circulating flow.

[0018] There is a gas gap 12 between the armature 4 and the magnetic shell 2, and the distance of the gas gap 12 is set to S: When S=0, the armature 4 is in contact with the magnetic shell 2; When S > 0, there is magnetic flow between armature 4 and magnetic shell 2.

[0019] The distance of the gas gap 12 varies with the position of the armature 4, achieving two stable states: A) Braking state: When armature 4 is in contact with the outer magnetic pole surface and the inner magnetic pole surface, the gas gap S=0; And, when armature 4 is in contact with the outer magnetic pole surface but not with the inner magnetic pole surface, the gas gap S=0; B) Release state: When armature 4 is separated from the inner and outer magnetic pole surfaces, the gas gap S=a, where a>0.

[0020] The gas gap 12 refers to the air medium layer formed between the armature 4 and the magnetic shell 2, which moves up and down due to the electromagnetic force on the armature 4, creating a changing gap distance. The outer magnetic pole face refers to the annular end face of the magnetic shell 2 near the gas gap 12, used to establish a magnetic flux path. The inner magnetic pole face 11 refers to the annular end face of the inner magnetic pole 11 near the gas gap 12.

[0021] Specifically, the gas gap 12 can be adjusted by electromagnetic force control, and the magnetic force can be changed by controlling the gap distance. Specifically, when coil 10 is energized, the magnetic field drives armature 4 to move axially, causing a change in the distance S of the gas gap 12. When S equals 0, armature 4 is in direct contact with the magnetic shell 2, forming mechanical braking, and magnetic lines of force are transmitted through the contact surface. When S is greater than 0, magnetic lines of force form a closed loop through the gas gap 12, achieving non-contact magnetic force transmission. The switching between these two states is accomplished by adjusting the direction or intensity of the current in coil 10, thereby achieving a bistable switching between braking and release. This application dynamically adjusts the gas gap 12 so that the contact state between the armature 4 and the magnetic shell 2 can be adaptively changed according to the working conditions. Furthermore, this application solves the problem of magnetic force attenuation and mechanical damage caused by thermal expansion of permanent magnets under high temperature environment. It reduces the rigid impact between armature 4 and magnetic shell 2 through the buffering effect of gas gap 12, while optimizing the stability of magnetic force transmission path, ensuring the reliability and durability of brake under complex working conditions.

[0022] The end face of the magnetic shell 2 near the gas gap 12 is the outer magnetic pole face, and the end face of the inner magnetic pole 1 near the gas gap 12 is the inner magnetic pole face. The inner magnetic pole face is at the same horizontal level as the outer magnetic pole face or the inner magnetic pole face is slightly lower than the outer magnetic pole face.

[0023] The outer magnetic pole surface refers to the annular plane at the end of the magnetic shell 2 that contacts the armature 4, and its function is to construct the magnetic field transmission path. The inner magnetic pole 11 is used to accelerate the response speed of the brake. Being horizontally aligned means that the outer magnetic pole surface and the inner magnetic pole 11 surface are on the same axial plane, which can be achieved by adjusting the assembly depth of the inner magnetic pole 11, and its function is to control the magnitude of the magnetic force generated by the coil 10. The inner magnetic pole 11 surface being slightly lower than the outer magnetic pole surface means that the inner magnetic pole 11 surface is axially offset from the outer magnetic pole surface into the magnetic shell 2, which can be achieved by setting a limiting step at the installation position of the inner magnetic pole 11.

[0024] The second mounting area 9, formed by the inner sleeve 6 and the outer sleeve 8, refers to the magnetically conductive material in the annular space between the two concentric cylinders, which is precision machined to ensure coaxiality. The first permanent magnet 7 is installed in the annular space, specifically using segmented neodymium iron boron magnets, with its radial magnetization direction perpendicular to the cylinder axis. The size change of the gas gap 12 is achieved by the axial displacement of the armature 4. The distance of the gas gap 12 can be controlled within the range of 0.1 to 0.5 mm. The magnetic coupling system switches its working mode by the alignment of the inner and outer magnetic pole surfaces. When the outer magnetic pole surface contacts the armature 4, it enters a braking state; when separated, it enters a release state. The magnetization direction of the cross section of the first permanent magnet 7 is the annular magnetic field line formed between the inner sleeve S6 and the outer sleeve N8, and the direction of the annular magnetic field line is clockwise or counterclockwise.

[0025] When a positive current is applied to the coil 10, the magnetic field generated by the first permanent magnet 7 forms a first annular magnetic field along the inner sleeve 6 and the outer sleeve 8, and the magnetic field generated by the second permanent magnet 13 forms a second annular magnetic field along the inner magnetic pole 11 near the brake 1. At this moment, the first ring magnetic field is in a clockwise direction, and the second ring magnetic field is in a clockwise direction.

[0026] Specifically, when a positive current is applied to coil 10, the magnetic field of coil 10 is superimposed on the magnetic field of the second permanent magnet 13, forming a second clockwise annular magnetic field in the region of armature 4. At the same time, the first permanent magnet 7 forms a first clockwise annular magnetic field through the sleeve structure. The two magnetic fields generate magnetic forces in the same direction in the region of armature 4, and the rapid switching of braking state is achieved through magnetic coupling.

[0027] The first annular magnetic field refers to the closed annular path formed by the magnetic field of the first permanent magnet 7 between the inner sleeve 6 and the outer sleeve 8. Specifically, it can be achieved by using a magnetically conductive material to fabricate the inner sleeve 6 and the outer sleeve 8, thereby constraining the direction of the magnetic field lines through the magnetic conductivity of the inner sleeve 6 and the outer sleeve 8. The second annular magnetic field refers to the closed annular path formed by the magnetic field of the second permanent magnet 13 in the region of the armature 4, so that the direction of the magnetic field is superimposed on the first annular magnetic field.

[0028] This scheme utilizes the synergistic effect of the magnetic fields of the first permanent magnet 7 and the second permanent magnet 13 to cancel each other out in the armature 4 when the power is on, and to form a closed loop to maintain a stable holding force when the power is off.

[0029] This design utilizes the inner sleeve 6, outer sleeve 8, and magnetic shell 2 to form a multi-stage annular closed magnetic circuit. This ensures that the permanent magnet's magnetic field is always conducted along a low magnetic reluctance path, avoiding magnetic field strength loss caused by disordered diffusion of magnetic field lines. Simultaneously, the superposition design of the magnetic field significantly improves the response speed and effectively reduces the risk of demagnetization of the permanent magnet under high-temperature conditions. The annular closed magnetic circuit reduces magnetic energy loss due to magnetic field leakage, keeping the operating point of the first permanent magnet 7 consistently within a stable region. The mechanical support provided by the magnetic guiding structure of the inner sleeve 6 and outer sleeve 8 disperses the stress borne by the first permanent magnet 7, avoiding the fracture problem caused by the first permanent magnet 7 directly bearing mechanical loads in traditional structures.

[0030] Through the above technical solution, this application effectively solves the problem of demagnetization of permanent magnets under high-temperature conditions. The annular magnetic circuit design makes the magnetic field distribution more uniform, avoiding material fatigue caused by excessive local magnetic flux density. Simultaneously, the sleeve structure provides mechanical support for the two permanent magnets, enabling them to adapt to dimensional changes caused by thermal expansion and contraction, significantly reducing the risk of permanent magnet breakage. In frequent start-stop scenarios, the rapid switching characteristics of the closed magnetic circuit ensure timely braking response, while the self-sustaining magnetic field in the power-off state maintains the stability of the release state.

[0031] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A bistable electromagnetic brake, characterized in that, include: Stator connector (1); A magnetic shell (2) is installed on the outside of the stator connector (1), and the magnetic shell (2) is a hollow shell; The rotor connector (3) is installed at one end of the stator connector (1), the stator connector (1) is fixed, and the rotor connector (3) is rotatably connected to the stator connector (1). An armature (4) is sleeved between the magnetic shell (2) and the rotor connector (3), and the armature (4) and the rotor connector (3) are connected by a number of elastic connectors (14). A first mounting area (5) is formed between the rotor connector (3) and the boss area of ​​the armature (4). The first mounting area (5) is provided with an inner sleeve (6), a first permanent magnet (7) and an outer sleeve (8). The outer sleeve (8) is located outside the inner sleeve (6). The inner sleeve (6) and the outer sleeve (8) are detachably connected to the rotor connector (3). The inner sleeve (6) and the outer sleeve (8) form an annular structure sleeved on the rotor connector (3). A second mounting area (9) is reserved between the inner sleeve (6) and the outer sleeve (8). The first permanent magnet (7) is installed inside the second mounting area (9). The magnetic shell (2) is also provided with a coil (10), an inner magnetic pole (11), and a second permanent magnet (13). The coil (10) is installed inside the magnetic shell (2), the second permanent magnet (13) is installed at the bottom of the inner side of the coil (10), and the inner magnetic pole (11) is located at the top of the second permanent magnet (13). There is a gas gap (12) between the armature (4) and the magnetic shell (2). The distance of the gas gap (12) changes with the position of the armature (4) relative to the magnetic shell (2). The first permanent magnet (7) forms a magnetic coupling with the armature (4). When the coil (10) is energized, the magnetic field generated by the coil (10) works together with the magnetic fields of the first permanent magnet (7) and the second permanent magnet (13) to change the magnetic force acting on the armature (4), and achieve the switching between the braking state and the release state under the action of the reset force provided by the elastic connector (14); Furthermore, when the magnetic field generated by the first permanent magnet (7) is generated, the magnetic force flowing between the inner sleeve (6), the armature (4) and the outer sleeve (8) forms a circulating flow.

2. The bistable electromagnetic brake according to claim 1, characterized in that, A first slot is provided on one side of the inner sleeve (6) opposite to the second mounting area (9); A second slot is provided on one side of the outer sleeve (6) relative to the second mounting area (9); The first slot, the second slot, and the reserved gap between the outer sleeve (8) and the inner sleeve (6) together form the second installation area, so that the first permanent magnet (7) is snapped into the second installation area (9).

3. A bistable electromagnetic brake according to claim 2, characterized in that, There is a gas gap (12) between the armature (4) and the magnetic shell (2), and the distance of the gas gap (12) is set to S: When S=0, the armature (4) is in contact with the magnetic shell (2); When S > 0, there is magnetic flow between the armature (4) and the magnetic shell (2).

4. A bistable electromagnetic brake according to claim 3, characterized in that, The end face of the magnetic shell (2) near the gas gap (12) is the outer magnetic pole face, and the end face of the inner magnetic pole (1) near the gas gap (12) is the inner magnetic pole face. The inner magnetic pole face is level with the outer magnetic pole face or the inner magnetic pole face is slightly lower than the outer magnetic pole face.

5. The bistable electromagnetic brake structure according to claim 4, characterized in that, The size of the gas gap (12) varies with the position of the armature (4), achieving two stable states: A) Braking state: When the armature (4) is in contact with the outer magnetic pole surface and the inner magnetic pole surface, the gas gap S=0; And, when the armature (4) is in contact with the outer magnetic pole surface but not with the inner magnetic pole surface, the gas gap S = 0; B) Release state: When the armature (4) is separated from the inner magnetic pole surface and the outer magnetic pole surface, the gas gap S=a, where a>0.

6. A bistable electromagnetic brake according to claim 5, characterized in that, One end of the elastic connector (14) is connected to the rotor connector (3), and the other end is connected to the armature (4). The elastic connector (14) provides the armature (4) with a reset force away from the inner magnetic pole (11).

7. A bistable electromagnetic brake according to claim 6, characterized in that, The magnetization direction of the cross section of the first permanent magnet (7) is the annular magnetic field line formed between the inner sleeve S (6) and the outer sleeve N (8), and the direction of the annular magnetic field line is clockwise or counterclockwise.

8. A bistable electromagnetic brake according to claim 7, characterized in that, When a positive current is applied to the coil (10), the magnetic field generated by the first permanent magnet (7) forms a first annular magnetic field along the inner sleeve (6) and the outer sleeve (8), and the magnetic field generated by the second permanent magnet (13) forms a second annular magnetic field along the inner magnetic pole (11) near the brake (1). At this time, the first annular magnetic field is in a clockwise direction, and the second annular magnetic field is in a clockwise direction.

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