A magnetic bistable electromagnetic brake and carbon fiber cycloid joint assembly
By combining a magnetic bistable electromagnetic brake with carbon fiber materials, the problems of rapid response and low energy consumption of robot joint brakes during power failure are solved, achieving lightweight and integrated design of the brake and meeting the high standards of safety and flexibility required by humanoid robots.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN WU SHI LIHUA PRECISION MANUFACTURING CO LTD
- Filing Date
- 2026-04-08
- Publication Date
- 2026-06-26
AI Technical Summary
Existing robot joint actuators cannot simultaneously meet the requirements of rapid response during sudden power outages, steady-state zero energy consumption, lightweight design, and compact layout. They also suffer from problems such as high energy consumption, complex structure, susceptibility to dust contamination, and rapid wear.
The device employs a magnetic bistable electromagnetic brake, which utilizes the magnetic cooperation between a permanent magnet and a magnetically conductive sliding block, combined with an electromagnetic coil to control the movement of the sliding block, thereby achieving braking and release. The response is accelerated by the reverse discharge of a capacitor or rechargeable battery, and a steady state is maintained when the power is off. The brake is built into the joint assembly, and carbon fiber material is used to reduce weight and volume.
It achieves low-energy consumption, fast response and high reliability braking, meets the safety and lightweight requirements of humanoid robots, reduces the energy consumption and wear of the brake, and meets the requirements of joint miniaturization and integration.
Smart Images
Figure CN122280980A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of brake technology. Background Technology
[0002] As high-end intelligent equipment, humanoid robots have stringent performance requirements for their joint components' braking devices. These devices must ensure emergency locking safety in the event of sudden power outages or malfunctions, while also achieving lightweight, low-energy consumption, and compact design to accommodate the limited installation space and flexible movement needs of the joints. Traditional robot joints often use ordinary electromagnetic brakes or mechanical friction brakes, which cannot simultaneously meet the core requirements of power failure self-locking, steady-state zero energy consumption, and rapid response. This has gradually become a key bottleneck restricting the improvement of robot joint performance.
[0003] Most existing conventional electromagnetic brakes rely on continuous power to maintain braking or release, resulting in high energy consumption over long periods of operation. Furthermore, they are prone to braking lag and unstable locking after power failure. Some products also suffer from loose structures, susceptibility to dust and impurities in internal components, and rapid wear of friction parts, leading to short lifespans and frequent maintenance. In addition, conventional brakes are generally heavy, contradicting the design principles of lightweight robot joints and high load-bearing ratios, and failing to meet the high standards of weight and operational flexibility required by humanoid robots.
[0004] Some bistable brakes use mechanical locking structures to maintain their state, but such solutions are often complex and require additional mechanical self-locking mechanisms in the brake. This not only increases manufacturing costs and assembly difficulty, but also adversely affects the brake's response speed and reliability. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a magnetic bistable electromagnetic brake and a carbon fiber cycloidal joint assembly.
[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution:
[0007] A magnetic bistable electromagnetic brake includes a motor rotor, a braking magnet, a splined shaft, a release magnet, a sliding block, and a displacement cavity; The sliding block, the braking magnet, the disengaging magnet, and the splined shaft are all located within the displacement cavity; One end of the detached magnet is fixed to the fixed end of the brake, and the other end is set toward the sliding block; The sliding block is slidably engaged with the spline shaft. The sliding block is made of a magnetic material and can form a magnetic attraction with the magnetic component. The sliding block slides along the spline shaft. The brake magnet has a brake pad at one end facing the sliding block. One end of the brake magnet is fixed to the motor rotor. The brake magnet is located on the moving trajectory of the sliding block. When the sliding block moves toward the brake magnet to the end point, the sliding block and the brake pad engage with each other. A drive assembly is also provided, which drives the sliding block to move along the spline shaft, causing the sliding block to move away from the brake pad.
[0008] With the above scheme, when the magnetic bistable electromagnetic brake is working, the motor rotor drives the brake magnet and brake pad to rotate synchronously. The sliding block slides axially along the spline shaft in the displacement cavity. The drive component can drive the sliding block away from the brake pad to release the brake. When the sliding block moves towards the brake magnet to the end point, it engages with the brake pad to form a brake. This structure integrates core components such as the brake magnet, release magnet, and sliding block into the displacement cavity. The spline shaft ensures the movement accuracy and circumferential limit of the sliding block. The basic braking and release actions are achieved by the magnetic cooperation between the permanent magnet and the magnetically conductive sliding block. The overall structure is compact and can maintain its state without continuous power supply. It has the basic characteristics of magnetic bistable. At the same time, the layout of each component is reasonable and can adapt to the braking requirements of rotary actuators, significantly reducing the energy consumption of the brake.
[0009] Furthermore, the driving component includes a groove disposed on the sliding block, and an electromagnetic coil disposed within the groove; After the electromagnetic coil is energized, the side of the sliding block facing the brake magnet has the same polarity as the side opposite the brake magnet. Then the sliding block moves along the spline shaft and disengages from the brake pad on the brake magnet and attracts the disengagement magnet, and the brake is in the released state. When the electromagnetic coil is energized in reverse, the side of the sliding block facing the brake magnet has the opposite polarity to the side opposite the brake magnet. Then, the sliding block moves along the spline shaft and disengages from the disengagement magnet, forming an adsorption engagement with the brake pad on the brake magnet, and the brake is in a braking state.
[0010] In the above scheme, the electromagnetic coil is embedded in the groove of the sliding block, and the direction of the magnetic field is controlled by changing the direction of energization. When the electromagnetic coil is energized, the sliding block is magnetized, and the side of the sliding block facing the braking magnet repels the same pole of the braking magnet, pushing the sliding block to move towards the detachment magnet and attracting it. At this time, the side of the sliding block facing the detachment magnet attracts the opposite pole of the detachment magnet, and the brake is in the released state. When the electromagnetic coil is energized in the reverse direction, the sliding block is magnetized, and one end of the sliding block repels the same pole of the detachment magnet, pushing the sliding block towards the braking magnet and attracting it. The brake is in the braking state. At the same time, the overall polarity of the sliding block can also be changed by reversing the power supply to the electromagnetic coil, causing the sliding block to move away from the detachment magnet and towards the braking magnet, thereby maintaining the steady state of the device.
[0011] Furthermore, a power failure rapid response component is provided, which includes an electrically connected controller and a capacitor or rechargeable battery. The electrically connected controller and the capacitor or rechargeable battery are connected to the electromagnetic coil and configured to briefly reverse discharge from the capacitor or rechargeable battery to the electromagnetic coil at the moment of power failure, causing the polarity of the sliding block to reverse and accelerating the movement of the sliding block. The controller is equipped with a position sensor to determine whether the brake is in a braking or releasing state.
[0012] The above scheme connects the controller and a capacitor or rechargeable battery to the electromagnetic coil. Upon power failure, the capacitor or battery briefly reverse-discharges into the electromagnetic coil, generating a reverse magnetic field that accelerates the transition of the slider from the released state to the braking state. Simultaneously, the controller's position sensor monitors the slider's position in real time, accurately determining whether the brake is currently in a braking or released state. This solves the problem of brake response delay during unexpected power outages, ensuring that the brake can quickly and reliably enter the braking state in the event of a power failure. The state switching is briefly triggered by an electromagnetic pulse, typically 20ms-100ms, after which a permanent magnet maintains a steady state. This achieves a balance between low power consumption and high response speed, making it particularly suitable for applications with extremely high safety requirements, such as humanoid robots.
[0013] Furthermore, the sliding block has a boss on the side facing the brake pad, and the brake pad has several grooves distributed on its outer periphery. The grooves are conical. When the electromagnetic coil is energized in the reverse direction, the sliding block moves along the spline shaft and disengages from the release magnet. Under the attraction of the braking magnet, the boss on the sliding block and the groove on the brake pad engage with each other to complete braking. When the electromagnetic coil is energized, the side of the sliding block facing the braking magnet has the same polarity as the side opposite the braking magnet. The boss separates from the groove, and the sliding block moves along the spline shaft and attracts the release magnet.
[0014] With the above scheme, when the electromagnetic coil is energized in the reverse direction, the sliding block moves towards the brake pad under the attraction of the braking magnet. The boss and the conical groove automatically align and fit tightly, achieving dual locking braking through mechanical and magnetic forces. When the electromagnetic coil is energized in the forward direction, the boss separates from the groove, and the sliding block moves away from the magnet. The conical design not only reduces the impact during engagement but also automatically corrects deviations, ensuring precise alignment for each braking action and improving braking reliability and repeatability.
[0015] Furthermore, the brake surface of the brake pad is made of a material with a high coefficient of friction, and the brake surface of the sliding block facing the brake pad is also made of a material with a high coefficient of friction. The friction surface can be either a plane or a conical surface.
[0016] The above method uses a high-friction coefficient material to prepare the brake surface, which has strong wear resistance and can perform friction braking quickly.
[0017] Furthermore, a buffer pad is provided on the end face of the detached magnet facing the sliding block. The buffer pad is an elastic rubber pad or a polyurethane pad, and a metal reinforcing sheet is embedded inside the buffer pad.
[0018] With the above solution, when the sliding block moves rapidly towards and attracts the detached magnet under electromagnetic force, the buffer pad first contacts the sliding block and absorbs the impact energy through elastic deformation; the internal metal reinforcing plate prevents the buffer pad from excessively deforming and failing. This reduces the impact noise and vibration generated when the sliding block attracts the detached magnet, while protecting the end faces of the sliding block and the detached magnet from repeated impact damage, thus extending the service life of the brake.
[0019] Furthermore, both the braking magnet and the disengaging magnet are high coercivity permanent magnets, and the sliding block is made of electrical pure iron.
[0020] The above scheme uses high-performance, high-coercivity permanent magnets for the braking magnet and the release magnet, and electrical pure iron with excellent magnetic permeability for the sliding block, ensuring efficient transmission of magnetic circuit.
[0021] The present invention also provides a carbon fiber cycloidal joint assembly, including the above-mentioned magnetic bistable electromagnetic brake; it also includes a motor housing, a motor rear end cover, and a cycloidal reducer planetary carrier; the cycloidal reducer planetary carrier, the motor housing, and the motor rear end cover are all disposed on the outside of the magnetic bistable electromagnetic brake.
[0022] With the above solution, the brake is built into the joint assembly, which consists of a motor housing, a motor rear end cover, and a cycloidal reducer planetary structure. All peripheral components are located on the outside of the brake, forming a compact integrated structure. This layout makes full use of the axial space inside the joint, allowing the brake, motor, and reducer to form an integrated design. This achieves the braking function of the joint while avoiding the bulky size caused by an external brake, thus meeting the stringent requirements of humanoid robots for miniaturized and integrated joints.
[0023] Furthermore, the motor housing, the motor rear end cover, and the planetary carrier of the cycloidal reducer are all made of carbon fiber reinforced composite material.
[0024] The above approach significantly reduces the overall weight of the joint while ensuring sufficient structural strength. The high specific strength and excellent vibration damping characteristics of carbon fiber help reduce inertia and vibration during joint movement, making the humanoid robot's dynamic response more agile and its movement smoother.
[0025] The beneficial effects of this invention are as follows: 1. This invention features a simple structure, achieving a high degree of balance between extremely low energy consumption and intrinsic safety. Its core lies in utilizing the attraction and repulsion forces of permanent magnets to achieve bistable state maintenance. The electromagnetic coil is energized only during state transitions, eliminating the need for continuous power consumption under normal conditions, thus significantly reducing energy consumption. Simultaneously, the reverse discharge of a capacitor or rechargeable battery accelerates the response, achieving intrinsically safe failure protection without relying on a power source. This makes it particularly suitable for robot joints with stringent safety and endurance requirements. 2. The brake is built into the joint assembly, which consists of the motor housing, the motor rear end cover, and the planetary gearbox of the cycloidal reducer. All peripheral components are located on the outside of the brake, forming a compact integrated structure. This layout makes full use of the axial space inside the joint, allowing the brake, motor, and reducer to be integrated into a single design. This achieves the braking function of the joint while avoiding the bulky size caused by an external brake, thus meeting the stringent requirements of humanoid robots for miniaturization and integration of joints. Attached Figure Description
[0026] Figure 1 This is a partial structural schematic diagram of the magnetic bistable electromagnetic brake of the present invention; Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure along line AA; Figure 3 This is a schematic diagram of the overall cross-sectional structure of the present invention.
[0027] Reference numerals: 11. Motor rotor; 12. Brake magnet; 13. Splined shaft; 14. Disengagement magnet; 15. Sliding block; 16. Displacement cavity; 18. Brake pad; 19. Groove; 20. Electromagnetic coil; 21. Boss; 22. Groove; 23. Buffer pad; 24. Motor housing; 25. Motor rear end cover; 26. Cycloidal reducer planetary carrier. Detailed Implementation
[0028] 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0030] Example 1 Reference Figure 1 and Figure 2 This embodiment specifically discloses a magnetic bistable electromagnetic brake, including a motor rotor 11, a braking magnet 12, a splined shaft 13, a release magnet 14, a sliding block 15, and a displacement cavity 16; the sliding block 15, the braking magnet 12, the release magnet 14, and the splined shaft 13 are all disposed within the displacement cavity 16. One end of the release magnet 14 is fixedly installed to the brake's fixed end, and the other end is positioned towards the sliding block 15. A buffer pad 23 is provided on the side of the release magnet 14 facing the sliding block 15. The buffer pad 23 is made of elastic rubber and has an embedded metal reinforcing sheet, balancing buffering effect and service life.
[0031] The sliding block 15 is slidably engaged with the splined shaft 13. It is made of electrical pure iron and has excellent magnetic permeability, allowing it to form a stable magnetic adsorption fit with magnetic components and slide linearly along the splined shaft 13. One end of the brake magnet 12 is fixed to the motor rotor 11, and the other end facing the sliding block 15 is integrally provided with a brake pad 18. The brake magnet 12 is located within the moving trajectory of the sliding block 15. When the sliding block 15 moves toward the brake magnet 12 to the end point, the two engage with each other to achieve braking.
[0032] A groove 19 is formed on the sliding block 15, and an electromagnetic coil 20 is installed in the groove 19 to form a driving component. When the electromagnetic coil 20 is energized, it magnetizes the magnetically conductive sliding block 15, causing the side of the sliding block 15 facing the brake magnet 12 to form the same polarity as the opposite side of the brake magnet 12. After the electromagnetic coil 20 is energized, the magnetized sliding block 15 and the opposite side of the release magnet 14 form a magnetic field with opposite polarity, thus attracting the release magnet 14. The side of the sliding block 15 facing the brake magnet 12 and the brake magnet 12... When the opposite sides have the same polarity, they generate a repulsive force, pushing the sliding block 15 to slide along the spline shaft 13. At this time, when one end of the sliding block 15 is energized, its polarity is opposite to that of the opposite side of the disengaging magnet 14. Therefore, the sliding block 15 separates from the brake pad 18 and is attracted to the side of the disengaging magnet 14, and the brake is in the released state. When the electromagnetic coil 20 is energized in the reverse direction, the same polarity repulsive force between the sliding block 15 and the disengaging magnet 14 takes effect. The sliding block 15 separates from the disengaging magnet 14 along the spline shaft 13, is attracted by the brake magnet 12, and engages with the brake pad 18, and the brake is in the braking state.
[0033] In this embodiment, both the braking magnet 12 and the release magnet 14 are made of high-coercivity permanent magnets. The sliding block 15 has a boss 21 facing the brake pad 18. Several conical grooves 22 are evenly distributed around the outer periphery of the brake pad 18. When braking is applied in reverse, the boss 21 and the conical grooves 22 precisely engage; when energized, they easily separate. A separate power-off rapid response component is provided, including an electrical connection controller and a capacitor or rechargeable battery, both connected to the electromagnetic coil 20. At the moment of power failure, the capacitor briefly discharges in reverse to the electromagnetic coil 20, with a pulse typically between 20ms and 100ms, accelerating the movement of the sliding block 15. The discharge time is sufficient to support the sliding block 15's movement along the splined shaft and complete braking by the attraction of the braking magnet 12. The controller, equipped with a position sensor, determines the braking or release state of the brake in real time, thereby ensuring that the sliding block 15 remains attracted to the braking magnet 12 after power failure, maintaining the braking state.
[0034] In some embodiments, the brake surface of the brake pad 18 is made of a high-friction coefficient material, and the brake surface of the sliding block 15 facing the brake pad 18 is also made of a high-friction coefficient material. The friction surface can be either a plane or a conical surface. The high-friction coefficient material is carbon fiber reinforced ceramic matrix composite or copper-based powder metallurgy, and its friction coefficient is generally in the range of 0.4-0.55. Using a high-friction coefficient material to prepare the brake surface results in strong wear resistance and rapid friction braking.
[0035] Example 2 This embodiment is based on Embodiment 1, and refers to... Figure 1 and Figure 3 The present invention discloses a carbon fiber cycloidal joint assembly, including the magnetic bistable electromagnetic brake described in Embodiment 1, and further comprising a motor housing 24, a motor rear end cover 25, and a cycloidal reducer planetary carrier 26. The cycloidal reducer planetary carrier 26, the motor housing 24, and the motor rear end cover 25 are all located on the outside of the magnetic bistable electromagnetic brake, enclosing the brake to form a compact integrated structure, making full use of the axial space inside the joint, and realizing the integrated layout of the brake, motor and reducer.
[0036] In this embodiment, the motor housing 24, the motor rear end cover 25, and the cycloidal reducer planetary carrier 26 are all made of carbon fiber reinforced composite material. This significantly reduces the overall weight of the joint while ensuring structural strength and rigidity. Simultaneously, leveraging the material's inherent vibration damping characteristics, it weakens joint vibrations during operation, improving the smoothness of the humanoid robot's joint movement and its dynamic response sensitivity. The joint utilizes a built-in magnetic bistable electromagnetic brake to achieve automatic braking upon power failure and steady-state zero-energy operation, perfectly meeting the requirements for miniaturization, lightweight design, and high safety in humanoid robot joints.
[0037] It should be noted that the connection relationships of components not specifically mentioned in this application are all assumed to be based on existing technology. Since they do not involve the inventive point and are commonly used in existing technology, the structural connection relationships are not described in detail.
Claims
1. A magnetic bistable electromagnetic brake, characterized by It includes a motor rotor (11), a brake magnet (12), a splined shaft (13), a disengagement magnet (14), a sliding block (15), and a displacement cavity (16). The sliding block (15), the braking magnet (12), the disengaging magnet (14), and the spline shaft (13) are all located inside the displacement cavity (16); One end of the detachment magnet (14) is fixed to the brake fixing end, and the other end is set toward the sliding block (15); The sliding block (15) is slidably engaged with the spline shaft (13). The sliding block (15) is made of magnetic material and can form a magnetic adsorption fit with magnetic components. The sliding block (15) slides along the spline shaft (13). The brake magnet (12) has a brake pad (18) at one end facing the sliding block (15). One end of the brake magnet (12) is fixed to the motor rotor (11). The brake magnet (12) is located on the moving trajectory of the sliding block (15). When the sliding block (15) moves toward the brake magnet (12) to the end point, the sliding block (15) and the brake pad (18) are engaged with each other. A drive assembly is provided, which drives the sliding block (15) to move along the spline shaft (13).
2. The magnetic bistable electromagnetic brake according to claim 1, characterized in that, The driving component includes a groove (19) provided on the sliding block (15) and an electromagnetic coil (20) provided in the groove (19). When the electromagnetic coil (20) is energized, it magnetizes the magnetically conductive sliding block (15). Changing the energizing direction of the electromagnetic coil (20) causes the sliding block (15) to reciprocate along the spline shaft (13) to both ends. After the electromagnetic coil (20) is energized, the sliding block (15) faces the brake magnet (12) and has the same polarity on the opposite side of the brake magnet (12). Then the sliding block (15) moves along the spline shaft (13) and disengages from the brake pad (18) on the brake magnet (12), forming an adsorption fit with the disengaging magnet (14), and the brake is in the released state. When the electromagnetic coil (20) is energized in reverse, the sliding block (15) faces the brake magnet (12) with opposite polarity to the brake magnet (12). Then the sliding block (15) moves along the spline shaft (13) and disengages from the disengagement magnet (14), forming an adsorption engagement with the brake pad (18) on the brake magnet (12), and the brake is in a braking state.
3. A magnetically bistable electromagnetic brake according to claim 2, characterized in that, A power failure rapid response component is also provided. The power failure rapid response component includes an electrically connected controller and a capacitor or rechargeable battery. The electrically connected controller and the capacitor or rechargeable battery are connected to the electromagnetic coil (20) and are configured to discharge in reverse for a short time from the capacitor to the electromagnetic coil (20) at the moment of power failure, the polarity of the sliding block (15) is reversed, and the movement of the sliding block (15) is accelerated. The controller is equipped with a position sensor to determine whether the brake is in a braking or releasing state.
4. A magnetically bistable electromagnetic brake according to claim 2, characterized in that, The sliding block (15) has a boss (21) facing the brake pad (18). The brake pad (18) has several grooves (22) distributed on its outer periphery. The grooves (22) are conical. When the electromagnetic coil (20) is energized in the reverse direction, the sliding block (15) moves along the spline shaft (13) and disengages from the release magnet (14) with the same polarity. Under the attraction of the brake magnet (12), the boss (21) on the sliding block (15) and the groove (22) on the brake pad (18) engage with each other to complete braking. When the electromagnetic coil (20) is energized, the side of the sliding block (15) facing the brake magnet (12) has the same polarity as the side opposite to the brake magnet (12). The boss (21) separates from the groove (22). The sliding block (15) moves along the spline shaft (13) and attracts the release magnet (14).
5. A magnetically bistable electromagnetic brake according to claim 2, characterized in that, The brake surface of the brake pad (18) is made of a material with a high coefficient of friction, and the brake surface of the sliding block (15) facing the brake pad (18) is also made of a material with a high coefficient of friction. The friction surface can be either a plane or a conical surface.
6. A magnetically bistable electromagnetic brake according to claim 2, characterized in that, The detachment magnet (14) is provided with a buffer pad (23) on the side facing the sliding block (15). The buffer pad (23) is an elastic rubber pad or a polyurethane pad, and a metal reinforcing sheet is embedded inside the buffer pad (23).
7. A magnetically bistable electromagnetic brake according to claim 1, characterized in that, Both the braking magnet (12) and the detaching magnet (14) are high coercivity permanent magnets, and the sliding block (15) is made of electrical pure iron.
8. A carbon fiber cycloidal joint assembly, characterized in that, The device includes the magnetic bistable electromagnetic brake as described in any one of claims 1-7; it also includes a motor housing (24), a motor rear end cover (25), and a cycloidal reducer planetary carrier (26); the cycloidal reducer planetary carrier (26), the motor housing (24), and the motor rear end cover (25) are all disposed on the outside of the magnetic bistable electromagnetic brake.
9. A carbon fiber cycloidal joint assembly according to claim 8, characterized in that, The motor housing (24), the motor rear end cover (25), and the cycloidal reducer planetary carrier (26) are all made of carbon fiber reinforced composite material.