A detachable brake device based on magneto-rheological fluid

Abstract

The application belongs to the technical field of mechanical transmission and relates to a separable brake device based on magnetorheological fluid, which comprises a separation driving unit, a magnetic field generating unit, a main shaft brake unit, magnetorheological fluid and a control unit. The brake device drives the magnetic field generating unit to move in the axial direction of the main shaft through the separation driving unit, changes the effective magnetic flux area of the magnetic field generating unit and the main shaft brake unit, and the magnetorheological fluid filled between the brake cylindrical sheet body on the magnetic field generating unit and the main shaft changes from solid to liquid under the action of the magnetic field, and the viscous force also changes, so that the main shaft brake unit changes from providing braking torque to no torque rigid transmission, and the brake and non-brake functions are flexibly switched.

Description

Technical Field

[0001] This invention belongs to the field of mechanical transmission technology and relates to a separable braking device based on magnetorheological fluid design. Background Technology

[0002] Traditional rotary braking devices mostly employ contact friction braking, which results in significant frictional wear on the contact components during braking, reducing their lifespan. Furthermore, in addition to contact wear, traditional braking devices also generate frictional heat, causing a rapid rise in the surrounding temperature. This high temperature significantly impacts the overall performance of the device; for example, thermal deformation reduces the system's safety factor and accelerates component aging. Additionally, traditional rotary braking devices have low controllability over the frictional torque, making continuous stepless adjustment difficult, and the friction braking response time is also relatively long. In recent years, researchers have proposed rotary brakes based on magnetorheological fluids to address these issues.

[0003] Compared to traditional rotary braking devices, magnetorheological fluid-based rotary braking devices offer the advantage of rapid, stepless adjustment of impedance torque, with a response time in the millisecond range. Furthermore, this type of intelligent brake eliminates the frictional loss problem of traditional brakes, significantly extending the device's service life.

[0004] Magnetorheological fluids consist of microscale magnetic particles and a carrier fluid, with the magnetic particles distributed throughout the carrier fluid. In the absence of a magnetic field, the magnetic particles are randomly dispersed in the carrier fluid. Under the influence of a magnetic field, the magnetic particles align themselves in a row along the direction of the magnetic field, resulting in an increase in the yield stress perpendicular to the magnetic field direction as the magnetic field strength increases. By controlling the magnetic induction intensity, the yield stress of the liquid can be adjusted; this is the fundamental working mechanism of a magnetorheological fluid device.

[0005] Due to their advantages such as fast response, low power consumption, and highly controllable dynamic adjustment range, researchers have proposed numerous intelligent devices based on magnetorheological fluids in recent years, including magnetorheological fluid dampers, magnetorheological fluid rotary brakes, magnetorheological fluid shock absorbers, and magnetorheological fluid valves. These intelligent devices are currently widely used in intelligent actuators, lower limb prostheses, lower limb exoskeletons, and medical devices. Ossur, an international prosthetics company, has recently proposed a semi-passive human knee prosthesis based on a magnetorheological fluid rotary brake. This prosthesis mimics the movement function of the human knee joint in certain states by controlling the magnitude of the excitation current and adjusting the impedance torque of the prosthesis. Compared with traditional passive prostheses, this semi-active prosthesis significantly improves the wearer's gait and walking stability. However, within specified size and weight limitations, it is difficult to guarantee smooth swinging (low impedance torque under power-off conditions) and high torque support in the standing state (high impedance torque output under power-on conditions), thus limiting the further promotion of this type of prosthesis.

[0006] For magnetorheological fluid (MRF) devices, one of the most important performance indicators is the dynamic adjustment range of the device's impedance torque within specified size and weight limitations. This means that when the MRF device is powered off, the impedance torque must be sufficiently small to minimize its impact on other equipment; when the MRF device is powered on, the impedance torque must be sufficiently large to provide the required impedance torque. A larger dynamic adjustment range allows for a wider range of applications for the MRF device. Specifically, the aforementioned magnetorheological fluid semi-passive knee prosthesis suffers from reduced practicality due to its inability to meet performance requirements in terms of dynamic adjustment range. Furthermore, the integration of magnetorheological fluid dampers and rotary brakes with motors to form intelligent actuators is currently used in lower limb exoskeletons and robotic hands. In these applications, the magnetorheological fluid dampers and rotary brakes provide controllable impedance torque with a rapid response, thereby altering the compliance performance of the intelligent actuator. In these applications, the magnetorheological fluid dampers and rotary brakes need to provide the smallest possible impedance torque when powered off to reduce the consumption of the overall actuator's output torque. Furthermore, when energized, it is desirable that the impedance torque of the magnetorheological fluid damper and the magnetorheological fluid rotary brake be large enough so that the entire intelligent actuator will have a sufficiently large impedance adjustment range to meet the corresponding performance requirements.

[0007] Magnetorheological fluid rotary brakes mostly generate impedance torque by cutting the magnetorheological fluid through the relative motion between stator and rotor laminations. The stator and rotor laminations are mostly made of magnetically conductive materials, such as silicon steel or pure iron. A narrow meshing gap is formed between the stator and rotor laminations, filled with magnetorheological fluid. Another important component in the magnetorheological fluid rotary brake is the excitation unit, typically a coil with an iron core. By controlling the excitation current of the excitation unit, the magnetic field strength passing through the stator and rotor laminations, and the magnetorheological fluid filling the meshing gap between the stator and rotor, can be adjusted, thereby regulating the output impedance torque of the magnetorheological fluid rotary brake. In the de-energized state, the output impedance torque of the magnetorheological fluid rotary brake is mainly dominated by the viscous force of the magnetorheological fluid. This viscous force is inversely proportional to the width of the meshing gap between the stator and rotor laminations; that is, reducing the meshing gap width increases the impedance torque caused by the viscous force. Under energized conditions, the output impedance torque of a magnetorheological rotary brake is primarily dominated by the magnetic field-dependent force of the magnetorheological fluid. Increasing the meshing gap width reduces the impedance torque caused by the magnetic field-dependent force. Therefore, to satisfy a wide impedance torque adjustment range, a performance trade-off is required between the low viscous torque requirement under de-energized conditions and the high magnetic field-dependent torque requirement under energized conditions. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes a separable braking device based on magnetorheological fluid design, which can improve the dynamic adjustment range of the output impedance torque of existing magnetorheological fluid rotary brakes.

[0009] The technical solution of this invention to solve the above problems is: a separable braking device based on magnetorheological fluid design, characterized in that it includes:

[0010] A stator and a rotor, wherein a meshing clearance is formed between the stator and the rotor;

[0011] Output shaft, the rotor is fixed on the output shaft;

[0012] The housing forms an enclosed space to accommodate the stator, rotor, and output shaft;

[0013] Magnetorheological fluid, wherein the magnetorheological fluid fills the enclosed space within the outer shell;

[0014] The excitation unit is energized and the magnetic field it generates passes through the stator and the rotor and the meshing gap between them. When the power is turned off, the magnetic field generated by the excitation unit disappears.

[0015] A meshing and disengagement drive unit, wherein the meshing and disengagement drive unit actively adjusts one of the length of the meshing gap or the spacing of the gap between the stator and the rotor;

[0016] The control unit is used to control the magnitude of the excitation current of the excitation unit and to control and adjust the engagement / disengagement drive unit.

[0017] In one embodiment, the stator is a multi-turn concentric ring forming a comb-like shape, and the stator is made of either silicon steel or pure iron. When the excitation unit is energized, the stator can be rapidly energized, and when the excitation unit is de-energized, the stator can be rapidly de-energized.

[0018] In one embodiment, the rotor is a multi-ring concentric circle forming a comb-like shape, and the rotor is made of either silicon steel or pure iron. When the excitation unit is energized, the rotor can be rapidly energized, and when the excitation unit is de-energized, the rotor can be rapidly de-energized.

[0019] In one embodiment, the stator and the rotor interlock and form an interlocking gap, and the magnetorheological fluid fills the interlocking gap.

[0020] In one embodiment, the stator is formed by nesting multiple concentric cylinders of different diameters.

[0021] In one embodiment, the stator is formed by cutting a single cylinder to create multiple concentric rings, or the stator is formed by 3D metal printing to create multiple concentric rings.

[0022] In one embodiment, the rotor is formed by nesting multiple concentric cylinders of different diameters.

[0023] In one embodiment, the rotor is formed by cutting a single cylinder into multiple concentric rings, or the rotor is formed by 3D metal printing into multiple concentric rings.

[0024] In one embodiment, when the excitation unit is energized, a magnetic field is generated. The magnetic field passes through the stator, the rotor, and the meshing gap formed by the stator and the rotor. When the rotary braking device rotates to input or output, the output impedance torque increases; when the excitation unit is de-energized, the output impedance torque decreases; adjusting the excitation current of the excitation unit can adjust the impedance torque of the rotary braking device.

[0025] In one embodiment, the excitation unit is a multi-lobed iron core with uniformly distributed circumference, and each independent lobe of the iron core is shaped like a waist drum. The coil is wound around the middle part of the waist drum-shaped iron core for excitation.

[0026] In one embodiment, the engagement / disengagement drive unit is used to increase the dynamic adjustment range of the impedance torque of the rotary braking device, that is, to decrease the impedance torque of the rotary braking device when the excitation unit is de-energized and to increase the impedance torque of the rotary braking device when the excitation unit is energized.

[0027] In one embodiment, the meshing separation drive unit reduces the meshing length of the meshing gap between the stator and the rotor, while increasing the width of the gap through which the rotor cuts the magnetorheological fluid. When the excitation unit is de-energized, the impedance torque of the rotary braking device decreases. This impedance torque mainly includes mechanical friction torque and viscous torque of the magnetorheological fluid.

[0028] In one embodiment, the meshing separation drive unit increases the meshing length of the meshing gap between the stator and the rotor, while reducing the width of the gap where the rotor cuts the magnetorheological fluid. When the excitation unit is energized, the impedance torque of the rotary braking device increases. This impedance torque mainly includes the magnetic field-related torque of the magnetorheological fluid, the viscous torque of the magnetorheological fluid, and the mechanical friction torque.

[0029] In one embodiment, the engagement / disengagement drive unit includes a motor, a transmission mechanism, and a lead screw and nut pair. One of the stator and the rotor is connected to the nut in the lead screw and nut pair. The motor can drive the lead screw in the lead screw and nut pair to rotate through the transmission mechanism, causing the nut to move forward and backward, thereby changing the engagement length of the engagement gap between the stator and the rotor.

[0030] In one embodiment, the engagement / disengagement drive unit has a power-off retention function, that is, when the engagement / disengagement drive unit is powered off, the engagement length of the engagement gap between the rotor and the stator remains unchanged, thereby reducing the energy consumption of the entire device.

[0031] In one embodiment, the lead screw is fixed to the housing by a bearing, a nut engages with the lead screw, and the stator is fixed to the nut; the lead screw is hollow, the main shaft passes through the inside of the lead screw and is connected to the lead screw by a bearing, and the rotor is fixed to the main shaft.

[0032] In one embodiment, the transmission mechanism is: a driving pulley and a driven pulley, or a driving gear and a driven gear, or a driving sprocket and a driven sprocket.

[0033] Advantages of this invention:

[0034] The purpose of this invention is to provide a separable rotary braking device based on magnetorheological fluid. By adjusting the meshing length and meshing width of the gear gap between the rotor and stator inside the device, the dynamic adjustment range of the output impedance torque of the rotary braking device is improved, thereby enhancing the performance of the magnetorheological fluid separable rotary braking device in prostheses, exoskeletons, and intelligent actuators. Specifically, to reduce the output impedance torque of the rotary braking device when power is off, the meshing length of the gear gap between the rotor and stator inside the device is reduced, while the meshing width of the gear gap is increased. To improve the output impedance torque of the rotary braking device when power is on, the meshing length of the gear gap between the rotor and stator inside the device is increased, while the meshing width of the gear gap is decreased. For example, a semi-passive knee prosthesis based on this magnetorheological fluid separable rotary braking device can provide a lower impedance torque in the swinging state, ensuring smooth knee joint swing; and in the standing state, it can provide a sufficiently large impedance support torque to support the body weight of the amputee, thereby improving the overall walking assistance function of the prosthesis. Furthermore, it should be noted that altering the meshing length and width of the gear gap between the internal rotor and stator will change the magnetic field distribution of the magnetorheological fluid within the gap. Increasing the meshing length and decreasing the meshing width will increase the magnetic field strength of the magnetorheological fluid in the gap under the same excitation current. Conversely, decreasing the meshing length and increasing the meshing width will decrease the magnetic field strength of the magnetorheological fluid in the gap under the same excitation current. Attached Figure Description

[0035] Figure 1 This is a front view of an embodiment of the present invention;

[0036] Figure 2 This is a left view of an embodiment of the present invention;

[0037] Figure 3 This is a top view of an embodiment of the present invention;

[0038] Figure 4 This is a front view sectional view of an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram illustrating the working principle of an embodiment of the present invention;

[0040] Figure 6 This is a two-dimensional magnetic field analysis (small engagement length) of an embodiment of the present invention;

[0041] Figure 7 This is a three-dimensional magnetic field analysis (small engagement length) of an embodiment of the present invention;

[0042] Figure 8 This is a two-dimensional magnetic field analysis (large engagement length) of an embodiment of the present invention;

[0043] Figure 9 This is a three-dimensional magnetic field analysis (large engagement length) of an embodiment of the present invention.

[0044] As shown in the figure:

[0045] Main component 1, Screw 1, 2, Front end cover 3, Protective shell 4, Bearing 1, 5, Synchronous belt 6, Large synchronous pulley 7, Screw drive shaft 8, Screw 2, 9, Main shaft 10, Bearing 2, 11, Elastic retaining ring for hole 12, Nut drive component 13, Screw 3, 14, Screw 4, 15, Small synchronous pulley 16, Set screw 17, Mounting base 18, Reducer 19, Motor 20, Magnetic cylindrical plate 1, 21, Magnetic cylindrical plate 2, 22, Magnetic... 23. Cylindrical plate three, 24. Magnetic cylindrical plate four, 25. Magnetic cylindrical plate five, 26. Screw five, 27. Rear end cap, 28. Brake cylindrical plate one, 29. Brake cylindrical plate two, 30. Brake cylindrical plate three, 31. Brake cylindrical plate four, 32. Plug, 33. Shaft elastic retaining ring one, 34. Bearing three, 35. Shaft elastic retaining ring two, 36. Sealing baffle, 37. Coil, 38. Soft iron core, 39. Guide rod, 40. Magnetorheological fluid. Detailed Implementation

[0046] 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 a part of the embodiments of the present invention, not all of them. 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. Therefore, the following detailed description of the embodiments of the present 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.

[0047] This invention proposes a separable braking device based on magnetorheological fluid design, comprising: a housing, a stator, a rotor, an output shaft, an excitation unit, a gear engagement / disengagement drive unit, and a control unit.

[0048] The housing forms a closed space to accommodate the stator, rotor, and output shaft; the stator and rotor rotate relative to each other, and a meshing gap is formed between them; the rotor is fixed to the output shaft; the magnetorheological fluid fills the closed space within the housing; the excitation unit is energized, and the resulting magnetic field passes through the stator and rotor and the meshing gap between them; the magnetic field formed by the excitation unit disappears after power is cut off; the meshing-disengagement drive unit actively adjusts either the length of the meshing gap or the spacing of the gap between the stator and rotor; the control unit is used to control the magnitude of the excitation current of the excitation unit and to control and adjust the meshing-disengagement drive unit.

[0049] In a preferred embodiment of the present invention, both the stator and the rotor are multi-turn concentric rings, each forming a comb-like tooth shape. The stator and the rotor interlock with each other, forming a tooth gap, and the magnetorheological fluid fills the tooth gap. The stator and the rotor are made of either silicon steel or pure iron. When the excitation unit is energized, both can be rapidly energized; when the excitation unit is de-energized, both can be rapidly de-energized.

[0050] In a preferred embodiment of the present invention, the stator is formed by nesting multiple concentric cylinders of different diameters.

[0051] Specifically, the stator can be formed by cutting a single cylinder to form multiple concentric rings, or by 3D metal printing to form multiple concentric rings.

[0052] In a preferred embodiment of the present invention, the rotor is formed by nesting multiple concentric cylinders of different diameters.

[0053] Specifically, the rotor can be formed by cutting a single cylinder to form multiple concentric rings, or by 3D metal printing to form multiple concentric rings.

[0054] In a preferred embodiment of the present invention, the excitation unit is a multi-lobed iron core with uniformly distributed circumference. Each independent lobe of the iron core is shaped like a waist drum, and the coil is wound around the middle part of the waist drum-shaped iron core for excitation.

[0055] When the excitation unit is energized, it generates a magnetic field that passes through the stator, the rotor, and the meshing gap formed by the stator and the rotor. When the rotary braking device rotates to input or output, the output impedance torque increases; when the excitation unit is de-energized, the output impedance torque decreases. Adjusting the excitation current of the excitation unit can adjust the impedance torque of the rotary braking device.

[0056] In one embodiment, the engagement / disengagement drive unit is used to increase the dynamic adjustment range of the impedance torque of the rotary braking device, that is, to decrease the impedance torque of the rotary braking device when the excitation unit is de-energized and to increase the impedance torque of the rotary braking device when the excitation unit is energized.

[0057] In one embodiment, the engagement / disengagement drive unit has a power-off retention function, that is, when the engagement / disengagement drive unit is powered off, the engagement length of the engagement gap between the rotor and the stator remains unchanged, thereby reducing the energy consumption of the entire device.

[0058] The engagement / disengagement drive unit reduces the engagement length of the stator and rotor, while simultaneously increasing the width of the gap through which the rotor cuts the magnetorheological fluid. When the excitation unit is de-energized, the impedance torque of the rotary braking device decreases. This impedance torque mainly includes the mechanical friction torque and the viscous torque of the magnetorheological fluid. The engagement / disengagement drive unit increases the engagement length of the stator and rotor, while simultaneously reducing the width of the gap through which the rotor cuts the magnetorheological fluid. When the excitation unit is energized, the impedance torque of the rotary braking device increases. This impedance torque mainly includes the magnetic field-dependent torque of the magnetorheological fluid, the viscous torque of the magnetorheological fluid, and the mechanical friction torque.

[0059] In some embodiments provided by this invention, the engagement / disengagement drive unit includes a motor, a transmission mechanism, and a ball screw and nut assembly. One of the stator and the rotor is connected to the nut in the ball screw and nut assembly. The motor can drive the lead screw in the ball screw and nut assembly to rotate via the transmission mechanism, causing the nut to move forward and backward, thereby changing the engagement length of the engagement clearance between the stator and the rotor. The motor can be either a stepper motor or a servo motor.

[0060] Specifically, the lead screw is fixed to the housing by a bearing, a nut cooperates with the lead screw, and the stator is fixed to the nut; the lead screw is hollow, the main shaft passes through the inside of the lead screw and is connected to the lead screw by a bearing, and the rotor is fixed to the main shaft.

[0061] The transmission mechanism can be a driving pulley and a driven pulley, or a driving gear and a driven gear, or a driving sprocket and a driven sprocket.

[0062] See Figures 1-4 The present invention discloses a rotary separable braking device based on magnetorheological fluid, the outer shell of which includes a main body component 1, a front end cover 3, and a rear end cover 27. A screw drive shaft 8 and a nut drive component 13 constitute a lead screw and nut pair.

[0063] The front cover 3 and the rear cover 27 are fixed to the main component 1 by screw 1 2 and screw 5 26 respectively, forming a limited sealed cylindrical cavity of the main structure.

[0064] The screw drive shaft 8 is mounted on the front end cover 3 via bearing 5. One end of the main shaft 10 is mounted on the screw drive shaft 8 via bearing 11, and the other end of the main shaft 10 is mounted on the rear end cover 27 via bearing 34, forming a structure in which the main shaft 10 can rotate within the sealed cylindrical cavity. The screw drive shaft 8 is connected to the large synchronous pulley 7 via screw 9, and the large synchronous pulley 7 is connected to the small synchronous pulley 16 via synchronous belt 6 to form a transmission mechanism. The reducer 19 is fixed to the front end cover 3 via mounting base 18. The input end of the reducer 19 is connected to the motor 20, and the output end is fixed to the small synchronous pulley 16 on the output shaft via set screw 17.

[0065] When the motor 20 rotates, it drives the small synchronous pulley 16 to rotate through the reducer 19. The small synchronous pulley 16 drives the large synchronous pulley 7 to rotate through the synchronous belt 6. The large synchronous pulley 7 is rigidly connected to the screw drive shaft 8, and they will rotate synchronously. The screw drive shaft 8 and the nut drive component 13 are threadedly fitted. When the screw drive shaft 8 rotates, the nut drive component 13 will form a linear motion on the screw drive shaft 8. The nut drive component 13 is sequentially connected to the magnetic cylindrical plate 1 21, magnetic cylindrical plate 22, magnetic cylindrical plate 3 23, magnetic cylindrical plate 4 24, and magnetic cylindrical plate 5 25. The magnetic cylindrical plate 1 21, magnetic cylindrical plate 22, magnetic cylindrical plate 3 23, magnetic cylindrical plate 4 24, and magnetic cylindrical plate 5 25 are concentrically arranged to form the stator. The excitation unit is a soft iron core 38, which is located inside the magnetic cylindrical plate 5 25. Multiple coils 37 are evenly distributed on the soft iron core 38. The sealing baffle 36 seals the excitation unit composed of the soft iron core 38 and the coils 37 inside the magnetic cylindrical plate 5 25. The sealing baffle 36 is fixed to the nut drive component 13 by the shaft elastic retaining ring 2 35.

[0066] Near the rear end cover 27, the main shaft 10 is sequentially connected to brake cylindrical plates 1-28, 29, 30, and 31. These four plates are concentrically arranged to form a rotor. A shaft elastic retaining ring 33 secures all brake cylindrical plates to the main shaft 10, forming a rigid connection. When the main shaft rotates, all brake cylindrical plates rotate together. The outer surface of cylindrical plate 1-21 has an arc-shaped guide groove, and the main body component 1 also has a corresponding guide groove. A guide rod 39 is located between the main body component 1 and cylindrical plate 1-21. The movable component, composed of a nut transmission component 13 and all the magnetically conductive cylindrical plates, is guided by the guide rod 39, ensuring that the entire movable component does not rotate and can only move linearly along the axial direction of the main shaft 10. A screw plug 32 is installed on the rear cover 27. Opening the screw plug 32 allows the magnetorheological fluid 40 to be injected into or discharged into the limited sealed cylindrical cavity of the main structure. The magnetorheological fluid 40 fills the entire limited sealed cylindrical cavity of the main structure, especially between all the magnetically conductive cylindrical plates and the braking cylindrical plates.

[0067] See Figure 4 and Figure 5 When the rotary separable braking device based on magnetorheological fluid of the present invention is in a high-resistance torque working state, all the magnetically conductive cylindrical plates and the braking cylindrical plates approach and mesh with each other, current flows through the coil 37, and a magnetic field is generated in the soft iron core 38. At this time, the magnetorheological fluid 40 between the magnetically conductive cylindrical plates and the braking cylindrical plates changes from liquid to solid, and its viscosity increases. When the main shaft 10 rotates, all the braking cylindrical plates will generate a braking torque under the action of the viscosity force of the magnetorheological fluid 40, thereby realizing the braking function. When the rotary separable braking device based on magnetorheological fluid of the present invention is in a low-impedance torque working state, all the magnetic cylindrical plates and the braking cylindrical plates are separated from each other or partially separated, which greatly reduces their effective meshing area. At the same time, no current flows through the coil 37 and no magnetic field is generated in the soft iron core 38. At this time, the magnetorheological fluid 40 between the magnetic cylindrical plates and the braking cylindrical plates changes from solid to liquid, its viscosity decreases, and it also has a lubricating effect. At this time, the main shaft 10 only transmits torque, and the rotary separable braking device does not produce a braking effect.

[0068] Figures 6-9 The results show the two-dimensional and three-dimensional magnetic field analysis of the stator and rotor under different meshing lengths in this invention. The magnetic field generated by the excitation unit can smoothly pass through the stator, rotor, and the magnetorheological fluid filling the space between the stator and rotor, thereby enabling the adjustment of the rotational torque of the rotary braking device by controlling the current of the excitation unit.

[0069] Furthermore, it should be noted that the rotary separable braking device based on magnetorheological fluid designed in this invention can be used alone or in combination with motors, elastic units, etc., for various joints of human upper and lower prostheses, joints of upper and lower limb exoskeletons, and joints of robotic arms, etc., to provide controllable impedance torque, improve system compliance, or switch the working modes of motors and elastic units.

[0070] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related system fields, are similarly included within the scope of protection of the present invention.

Claims

1. A separable braking device based on magnetorheological fluid design, characterized in that, include: A stator and a rotor, wherein a meshing clearance is formed between the stator and the rotor; Output shaft, the rotor is fixed on the output shaft; The housing forms an enclosed space to accommodate the stator, rotor, and output shaft; Magnetorheological fluid, wherein the magnetorheological fluid fills the enclosed space within the outer shell; The excitation unit is energized and the magnetic field it generates passes through the stator and the rotor and the meshing gap between them. When the power is turned off, the magnetic field generated by the excitation unit disappears. A meshing and disengagement drive unit, wherein the meshing and disengagement drive unit actively adjusts one of the length of the meshing gap or the spacing of the gap between the stator and the rotor; The control unit is used to control the magnitude of the excitation current of the excitation unit and to control and adjust the engagement / disengagement drive unit.

2. The separable braking device based on magnetorheological fluid design according to claim 1, characterized in that: The stator consists of multiple concentric rings forming a comb-like shape. When the excitation unit is energized, the stator can be quickly energized; when the excitation unit is de-energized, the stator can be quickly de-energized.

3. A separable braking device based on magnetorheological fluid design according to claim 1, characterized in that: The rotor is a multi-ring concentric circle forming a comb-like shape. When the excitation unit is energized, the rotor can be quickly energized; when the excitation unit is de-energized, the rotor can be quickly de-energized.

4. A separable braking device based on magnetorheological fluid design according to claim 1, characterized in that: The stator and the rotor interlock and form an interlocking gap, and the magnetorheological fluid fills the interlocking gap.

5. A separable braking device based on magnetorheological fluid design according to claim 2, characterized in that: The stator is formed by nesting multiple concentric cylinders of different diameters.

6. A separable braking device based on magnetorheological fluid design according to claim 5, characterized in that: The stator is formed by cutting a single cylinder to form multiple concentric rings, or the stator is formed by 3D metal printing to form multiple concentric rings.

7. A separable braking device based on magnetorheological fluid design according to claim 3, characterized in that: The rotor is formed by nesting multiple concentric cylinders of different diameters.

8. A separable braking device based on magnetorheological fluid design according to claim 7, characterized in that: The rotor is formed by cutting a single cylinder to create multiple concentric rings, or the rotor is formed by 3D metal printing to create multiple concentric rings.

9. A separable braking device based on magnetorheological fluid design according to claim 1, characterized in that: When the excitation unit is energized, it generates a magnetic field that passes through the stator, the rotor, and the meshing gap formed by the stator and the rotor. When the braking device rotates to input or output, the output impedance torque increases; when the excitation unit is de-energized, the output impedance torque decreases. Adjusting the excitation current of the excitation unit can adjust the impedance torque of the braking device.

10. A separable braking device based on magnetorheological fluid design according to claim 1, characterized in that: The excitation unit is a multi-lobed iron core with evenly distributed circumference. Each independent lobe of the iron core is shaped like a waist drum, and the coil is wound around the middle part of the waist drum-shaped iron core for excitation.

11. A separable braking device based on magnetorheological fluid design according to claim 1, characterized in that: The engagement / disengagement drive unit is used to increase the dynamic adjustment range of the braking device's impedance torque, that is, to decrease the braking device's impedance torque when the excitation unit is de-energized and to increase the braking device's impedance torque when the excitation unit is energized.

12. A separable braking device based on magnetorheological fluid design according to claim 11, characterized in that: The meshing separation drive unit reduces the meshing length of the meshing gap between the stator and the rotor, while increasing the width of the gap where the rotor cuts the magnetorheological fluid. When the excitation unit is de-energized, the impedance torque of the braking device decreases. This impedance torque mainly includes mechanical friction torque and viscous torque of the magnetorheological fluid.

13. A separable braking device based on magnetorheological fluid design according to claim 11, characterized in that: The meshing separation drive unit increases the meshing length of the meshing gap between the stator and the rotor, while reducing the width of the gap where the rotor cuts the magnetorheological fluid. When the excitation unit is energized, the impedance torque of the braking device increases. This impedance torque mainly includes the magnetic field-related torque of the magnetorheological fluid, the viscous torque of the magnetorheological fluid, and the mechanical friction torque.

14. A separable braking device based on magnetorheological fluid design according to claim 11, characterized in that: The engagement / disengagement drive unit includes a motor, a transmission mechanism, and a lead screw and nut pair. One of the stator and the rotor is connected to the nut in the lead screw and nut pair. The motor can drive the lead screw in the lead screw and nut pair to rotate through the transmission mechanism, causing the nut to move forward and backward, thereby changing the engagement length of the engagement gap between the stator and the rotor.

15. A separable braking device based on magnetorheological fluid design according to claim 14, characterized in that: The lead screw is fixed to the housing by bearings, and a nut cooperates with the lead screw. The stator is fixed to the nut. The lead screw is hollow, and the main shaft passes through the inside of the lead screw and is connected to the lead screw by bearings. The rotor is fixed to the main shaft.

16. A separable braking device based on magnetorheological fluid design according to claim 15, characterized in that: The transmission mechanism includes: a driving pulley and a driven pulley, or a driving gear and a driven gear, or a driving sprocket and a driven sprocket.

17. A separable braking device based on magnetorheological fluid design according to claim 16, characterized in that: The engagement / disengagement drive unit has a power-off retention function, that is, when the engagement / disengagement drive unit is powered off, the engagement length of the engagement gap between the rotor and the stator remains unchanged, thereby reducing the energy consumption of the entire device.

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