A bistable electromagnet

Abstract

The utility model relates to a kind of bistable electromagnet, comprising: shell is hollow bottom state;Upper cover is set to the top of shell. First through-hole is set in static core middle part, and static core is set to shell bottom and upper cover. Coil framework is set to shell interior, and coil framework is hollow, and coil framework outside is provided with first coil groove and second coil groove, and magnet slot is set between first coil groove and second coil groove. First permanent magnet is at least provided with four pieces, and is spaced apart in magnet slot. Movable iron core is movably set in coil framework, and movable iron core is opened with second through-hole along its axial direction. Follow-up iron core passes through second through-hole, and the middle part of follow-up iron core is fixedly connected with movable iron core. The utility model is provided with four pieces of first permanent magnet, so that circumferentially distributed permanent magnet forms stronger superimposed magnetic field, first permanent magnet is plane magnetization, and the setting of four first permanent magnets makes the magnetic field circumferential magnetization, increases electromagnetic force, reduces the loss of magnetic field outward diffusion, and enhances the magnetic force effect on movable iron core.

Description

Technical Field

[0001] This utility model relates to the field of electromagnet technology, and in particular to a bistable electromagnet. Background Technology

[0002] EMB (Electromechanical Braking) is a core component of modern automotive drive-by-wire technology. It completely eliminates traditional hydraulic lines, achieving braking by installing independent electronically controlled actuators on each wheel.

[0003] When the driver presses the brake pedal, the pedal sensor generates an electrical signal, which is transmitted to the central controller. The controller then instructs the brake actuators at the corresponding wheels to operate. The motors within these actuators convert rotational motion into linear force via a reduction gear, directly pushing the friction pads to clamp the brake disc and generate braking force. This system eliminates brake fluid and numerous hydraulic components, resulting in a simpler structure, extremely rapid response, and precise independent control of the braking force at each wheel. It is an indispensable key technology for advanced driver assistance systems and autonomous driving.

[0004] When braking is required, the ECU commands the motor to rotate, which in turn pushes the brake pads to clamp the brake disc via a transmission mechanism. When the desired braking force is reached, the motor stops rotating. At this point, the system needs a mechanism to firmly lock the current position to maintain the clamping force between the brake pads and the brake disc. If this locking mechanism fails, the vehicle will lose braking. To achieve this "locking" function, an internal ratchet-pawl mechanism is typically designed into the EMB actuator. Electromagnets are usually used within the EMB braking mechanism to lock the ratchet.

[0005] For example, the structure of such an electromagnet is described in Chinese Patent Publication No. CN112747115B, entitled "An Electromagnet for a Bistable Waterproof Parking Lock and its Manufacturing Process." A typical structure of this type of electromagnet involves an annular groove around the coil frame, within which two semi-circular permanent magnets are symmetrically embedded. The relatively large distance between the two poles of the semi-circular permanent magnets results in a larger proportion of sparse magnetic field lines and lower magnetic field utilization. Summary of the Invention

[0006] The purpose of this invention is to provide a bistable electromagnet to solve the problem of low magnetic field utilization of permanent magnets.

[0007] To achieve the above objectives, this utility model discloses a bistable electromagnet, comprising: a shell, which is hollow and has a bottom; a top cover, which is disposed on the top of the shell; a stationary iron core, which has a first through hole in its center and is disposed at the bottom of the shell and the top cover, with one end of the stationary iron core near the interior of the shell being frustoconical; a coil frame, which is disposed inside the shell and is hollow, with a first coil slot and a second coil slot on its exterior, and a magnet slot between the first coil slot and the second coil slot; a first coil and a second coil wound with enameled wire are respectively disposed in the first coil slot and the second coil slot; a terminal is disposed at the top of the coil frame, and the two ends of the first coil and the second coil are respectively connected to the terminal; a first permanent magnet, at least four of which are disposed at intervals in the magnet slots; and a movable iron core, which is movably disposed within the coil frame, with a second through hole along its axial direction and grooves at both ends of the movable iron core that match the shape of the stationary iron core. The following iron core passes through the second through hole, and the middle part of the following iron core is fixedly connected to the movable iron core. The two ends of the following iron core pass through the first through hole of the stationary iron core and are movably connected to the first through hole.

[0008] Preferably, the two stationary iron cores are arranged coaxially.

[0009] Preferably, the first permanent magnet is in the shape of a quarter-circle arc.

[0010] Preferably, the upper cover is provided with a relief groove for the coil bobbin to pass through.

[0011] Preferably, the magnet groove is provided with a partition plate, and there are four partition plates. The partition plates divide the magnet groove into four equal areas, and a first permanent magnet is placed in each area.

[0012] Preferably, one pole of the first permanent magnet is close to the follower iron core, and the other pole is far away from the follower iron core.

[0013] Specifically, the N pole of the first permanent magnet is positioned close to the follower core, while the S pole is positioned far away from the follower core.

[0014] Preferably, the bottom of the coil frame is integrally formed with a positioning post, and the bottom of the outer shell is provided with a positioning hole that cooperates with the positioning post.

[0015] Preferably, the top of the coil frame is integrally formed with a terminal base, and the terminal is mounted on the terminal base.

[0016] This utility model has the following beneficial effects: 1. This utility model uses four first permanent magnets to create a stronger superimposed magnetic field by circumferentially distributed permanent magnets. The first permanent magnets are magnetized in a planar manner. The four first permanent magnets magnetize the magnetic field circumferentially, increase the electromagnetic force, reduce the loss of the magnetic field spreading outward, and enhance the magnetic force on the movable iron core.

[0017] 2. This utility model features grooves at both ends of the movable iron core that match the shape of the stationary iron core. The tightly fitting frustum structure enhances the magnetic conductivity between the stationary and movable iron cores, allowing the magnetic force generated by the permanent magnet or coil to act more efficiently at the contact points, reducing magnetic resistance, and thus effectively improving the holding force. This ensures that the movable iron core is not easily displaced by external forces in a steady state, enhancing the overall structural stability. Attached Figure Description

[0018] Figure 1 This is an exploded view diagram provided in a specific embodiment of this utility model.

[0019] Figure 2 This is a schematic diagram of the overall structure provided in a specific embodiment of the present utility model.

[0020] Figure 3 This is a schematic diagram of the overall structure provided in a specific embodiment of the present utility model.

[0021] Figure 4 This is a cross-sectional view of the entire structure provided in a specific embodiment of this utility model.

[0022] Figure 5 This is a cross-sectional view of the entire structure provided in a specific embodiment of this utility model.

[0023] Figure 6 This is a schematic diagram of the coil frame structure provided in a specific embodiment of the present utility model.

[0024] Figure 7 This is a schematic diagram of the arrangement of the first permanent magnet provided in a specific embodiment of this utility model.

[0025] Figure 8 This is a cross-sectional view of the entire structure provided in the second specific embodiment of this utility model.

[0026] Explanation of symbols for main components: 1. Outer shell; 2. Static iron core; 3. First permanent magnet; 4. Coil frame; 41. First coil slot; 42. Second coil slot; 43. Magnet slot; 44. Separator; 45. Terminal block; 46. Terminal; 47. Positioning post; 5. Movable iron core; 51. Groove; 6. Follower iron core; 61. Mounting slot; 7. Second permanent magnet; 8. Top cover; 81. Relief slot; 91. First coil; 92. Second coil; 10. Hall switch. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0028] Example 1 like Figures 1-7 This utility model provides a bistable electromagnet, comprising: a shell 1, which is hollow and has a bottom; a top cover 8, which is disposed on the top of the shell 1; and a stationary iron core 2, which has a first through hole in its middle. The stationary iron core 2 is disposed at the bottom of the shell 1 and the top cover 8, and the two stationary iron cores 2 are coaxially arranged. The end of the stationary iron core 2 near the inside of the shell 1 is shaped like a frustum.

[0029] like Figure 6 As shown, the coil frame 4 is disposed inside the outer shell 1. The coil frame 4 is hollow. The outer side of the coil frame 4 is provided with a first coil groove 41 and a second coil groove 42. A magnet groove 43 is provided between the first coil groove 41 and the second coil groove 42. The first coil 91 and the second coil 92, which are made of enameled wire, are respectively disposed in the first coil groove 41 and the second coil groove 42. This can avoid the coils from becoming tangled or interfering with each other.

[0030] The top of the coil frame 4 is provided with a terminal 46, and the two ends of the first coil 91 and the second coil 92 are respectively connected to the terminal 46. The top of the coil frame 4 is integrally formed with a terminal base 45, and the terminal 46 is installed in the terminal base 45. The upper cover 8 is provided with a relief groove 81 for the terminal 46 to pass through. The relief groove 81 provided in the upper cover 8 allows the coil frame 4 to pass through, which does not affect the encapsulation and protection of the internal components by the upper cover 8, and allows the terminal 46 to extend smoothly for easy external circuit connection. This makes the overall structure more compact, the assembly more convenient, and can prevent the terminal 46 from being damaged by the pressure of the upper cover 8, ensuring the safety and reliability of the circuit connection. The overall design takes into account functional zoning, structural stability and assembly convenience, and improves the practicality and durability of the device.

[0031] At least four first permanent magnets 3 are provided. Before assembling the first permanent magnets 3, a movable iron core 5 is placed inside the coil frame 4. The four first permanent magnets 3 are attracted into the magnet slot 43 by magnetic force. Then, high-temperature tape is wrapped around the outside of the magnet slot 43 to complete the installation of the first permanent magnets 3. The first permanent magnets 3 are in the shape of a quarter-circle arc. A separator 44 is provided inside the magnet slot 43. Four separators 44 are provided, dividing the magnet slot 43 into four equal areas. One first permanent magnet 3 is placed in each area. One magnetic pole of the first permanent magnet 3 is close to the movable iron core 6, and the other magnetic pole is away from the movable iron core 6. Specifically, the N pole of the first permanent magnet 3 is set close to the movable iron core 6, and the S pole is set away from the movable iron core 6.

[0032] The first permanent magnet 3 is magnetized in a planar manner. Setting up four first permanent magnets 3 will magnetize the magnetic field circumferentially, increase the electromagnetic force, and enhance the magnetic force on the movable iron core 5. The cooperation between the quarter-circular arc and the separator 44 ensures that the permanent magnets are evenly and symmetrically distributed in the circumferential direction. Combined with the design of opposite magnetic poles, a stable and balanced magnetic field environment can be formed around the movable iron core 5, avoiding the movable iron core 5 from being biased or stuck due to uneven magnetic field. At the same time, this structure allows the magnetic force of the permanent magnets to work together to form a continuous and stable holding force, ensuring the reliable maintenance of the bistable state. It can also generate a more precise driving force when it cooperates with the coil magnetic field, improving the sensitivity and response speed of the device. The separator 44 can also fix the position of the permanent magnets and prevent them from being displaced due to magnetic interaction, further ensuring the stability of the overall magnetic field performance.

[0033] like Figure 4 and 5 As shown, the movable iron core 5 is movably disposed within the coil frame 4. The movable iron core 5 has a second through hole along its axial direction, and its two ends have grooves 51 that match the shape of the stationary iron core 2. The grooves 51 and the ends of the iron core form a precise fit. This shape matching reduces the gap when the two are in contact, making the magnetic field distribution more concentrated in the contact area and avoiding magnetic field dispersion loss. Simultaneously, the frustum-shaped design guides the movable iron core 5 to automatically align when it moves into position, ensuring stable contact and reducing magnetic force waste caused by misalignment. From the perspective of improving the electromagnet's holding force, the tightly fitted frustum structure enhances the magnetic circuit conductivity between the stationary iron core 2 and the movable iron core 5, allowing the magnetic force generated by the permanent magnet or coil to act more efficiently on the contact area, reducing magnetic resistance, thereby effectively improving the holding force. This ensures that the movable iron core 5 is not easily displaced by external forces in a steady state, enhancing the overall structural stability.

[0034] The follower iron core 6 passes through the second through hole, and its middle part is fixedly connected to the movable iron core 5. The follower iron core 6 is cylindrical, and its two ends pass through the first through hole of the stationary iron core 2 and are movably connected to the first through hole. The movable iron core 5 drives the follower iron core 6 to move. In this embodiment, the follower iron core 6 can be an iron column.

[0035] When the coil is energized in the forward direction, the movable iron core is subjected to a forward-pushing magnetic force, causing the movable iron core to move forward, and the movable iron core drives the follower iron core 6 to move forward; when the coil is de-energized, the movable iron core remains stationary under the action of the first permanent magnet 3.

[0036] When the coil is energized in reverse, the movable iron core is subjected to a backward magnetic force, causing the movable iron core to move backward, and the movable iron core drives the follower iron core 6 to move backward; when the coil is de-energized, the movable iron core remains stationary under the action of the first permanent magnet 3.

[0037] The bottom of the coil frame 4 is integrally formed with a positioning post 47, and the bottom of the outer shell 1 is provided with a positioning hole that matches the positioning post 47. This ensures that the relative position of the coil frame 4 with the outer shell 1, the stationary iron core 2 and other components is accurate, thereby ensuring the coordination of the internal magnetic circuit and mechanical structure. The integrally formed positioning post 47 has a stable structure and is tightly connected to the coil frame 4. This can enhance the installation stability of the coil frame 4 in the outer shell 1 and prevent the coil frame 4 from shifting due to vibration or other factors during the operation of the device. This also avoids the positional changes of components such as the coil and permanent magnet from affecting the magnetic field performance or mechanical action.

[0038] The top of the follower core 6 has a mounting groove 61, and the second permanent magnet 7 is installed in the mounting groove 61. Figure 8 A Hall switch 10 can be installed above the top cover 8. The Hall switch 10 is mounted on the PCB board, and its on / off state is determined by the magnetic properties of the second permanent magnet 7. As the second permanent magnet 7 moves with the follower core 6, it will approach or move away from the Hall switch 10. When the second permanent magnet 7 approaches the Hall switch 10, the magnetic field increases; when it moves away, the magnetic field decreases. If the magnetic field exceeds a certain value (greater than 7 mT), the Hall switch is on; if it is less than a certain value (2 mT), the Hall switch is off.

[0039] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A bistable electromagnet, characterized in that, include: The outer casing is hollow and has a bottom. A top cover, which is disposed on the top of the outer casing; A stationary iron core, wherein a first through hole is provided in the middle of the stationary iron core, the stationary iron core is provided at the bottom of the outer shell and the top cover, and the end of the stationary iron core near the inside of the outer shell is shaped like a frustum; A coil frame is disposed inside the outer shell. The coil frame is hollow. A first coil slot and a second coil slot are disposed on the outside of the coil frame. A magnet slot is disposed between the first coil slot and the second coil slot. The first coil and the second coil, formed by enameled wire, are respectively disposed in the first coil slot and the second coil slot; the top of the coil frame is provided with a terminal, and the two ends of the first coil and the second coil are respectively connected to the terminal; The first permanent magnet, at least four of which are arranged at intervals in the magnet slot; A movable iron core is movably disposed within the coil frame. The movable iron core has a second through hole along its axial direction, and the two ends of the movable iron core have grooves that match the shape of the stationary iron core. The following iron core passes through the second through hole, and the middle part of the following iron core is fixedly connected to the movable iron core. The two ends of the following iron core pass through the first through hole of the stationary iron core and are movably connected to the first through hole.

2. The bistable electromagnet according to claim 1, characterized in that: The two stationary iron cores are coaxially arranged.

3. A bistable electromagnet according to claim 1, characterized in that: The first permanent magnet is in the shape of a quarter circle.

4. A bistable electromagnet according to claim 1, characterized in that: The upper cover is provided with a clearance groove for the coil bobbin to pass through.

5. A bistable electromagnet according to claim 1, characterized in that: The magnet slot is provided with a partition plate, and there are four partition plates. The partition plates divide the magnet slot into four equal areas, and a first permanent magnet is placed in each area.

6. A bistable electromagnet according to claim 1, characterized in that: One pole of the first permanent magnet is close to the follower iron core, and the other pole is far away from the follower iron core.

7. A bistable electromagnet according to claim 6, characterized in that: The N pole of the first permanent magnet is positioned close to the follower iron core, while the S pole is positioned far away from the follower iron core.

8. A bistable electromagnet according to claim 1, characterized in that: The bottom of the coil frame is integrally formed with a positioning post, and the bottom of the outer shell is provided with a positioning hole that cooperates with the positioning post.

9. A bistable electromagnet according to claim 1, characterized in that: The top of the coil frame is integrally formed with a terminal base, and the terminal is mounted on the terminal base.

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