A kind of active-passive switching structure, switching method, knee joint system and mechanical leg

Abstract

The application belongs to the field of mechanical legs, and particularly relates to a main-passive switching structure, a switching method, a knee joint system and a mechanical leg. The main-passive switching structure comprises a driving wheel, a transmission wheel II, a driven wheel, a support and a clutch mechanism. The driving wheel and the driven wheel are rotationally arranged on the support, the driving wheel is connected with a rotary driving mechanism, and the driven wheel is used for being connected with a driving part of a knee joint structure. The clutch mechanism comprises an operation part and a locking part. The operation part comprises a rotating piece rotationally arranged on an axis of the driving wheel, and a clutch rod fixedly arranged on the rotating piece. The transmission wheel II is rotationally arranged on the clutch rod. The transmission wheel II is rotationally matched with the driven wheel or separated from the driven wheel by rotating the clutch rod. The main-passive switching structure is used for realizing quick switching of active and passive movements of the knee joint structure. After the rotary driving mechanism of the mechanical leg loses power, the knee joint structure can be switched to a passive movement state, so that the knee joint structure can still be used as a passive mechanical leg.

Description

Technical Field

[0001] This invention belongs to the field of mechanical legs, specifically relating to an active-passive switching structure, switching method, knee joint system, and mechanical leg. Background Technology

[0002] In the field of lower limb assistive devices such as above-knee prostheses and powered exoskeletons, active knee joint systems powered by rotating drive mechanisms such as motors can significantly improve users' mobility and gait naturalness. However, the operation of such systems is highly dependent on power supply. When the power is depleted or the drive system malfunctions (i.e., a "power outage"), the prosthesis or exoskeleton typically faces two dilemmas: First, the entire knee joint structure may completely lock or fail, causing the user's movement to be restricted or even fall, leaving the user in the awkward and dangerous situation of "power outage means stopping"; second, although the knee joint can still be passively bent, the traditional power transmission path is not effectively disconnected or the load is not released. Even if the drive mechanism stops outputting, its internal gear meshing resistance, motor electromagnetic damping, etc., may still be converted into significant joint movement resistance ("dragging feeling"), making passive swinging heavy, stiff, and unnatural, greatly consuming the user's physical energy, making it difficult to achieve smooth and efficient passive walking (such as the residual limb driving the lower leg to swing naturally), and exacerbating the user's "battery anxiety," making them worry about the battery level during use, limiting their range of activities and daily application scenarios (such as long-distance travel, emergency evacuation, etc.).

[0003] Furthermore, existing solutions for switching between active and passive modes, such as complex electromagnetic clutches, hydraulic separators, or multi-plate friction clutches, suffer from problems including structural complexity, heavy weight, bulky size, high cost, slow switching response, potential residual load or incomplete disengagement after switching, and decreased reliability after high-frequency switching or long-term use. These structures are often difficult to integrate seamlessly into the precision bionic knee joint drivetrain, and may still impose additional mechanical constraints or internal friction on the core transmission components in the disengaged state (passive mode), hindering the full utilization of its inherent passive stabilization mechanism and highly efficient natural oscillation characteristics. Therefore, there is an urgent need for an active-passive switching mechanism that is compact, reliable in operation, allows for rapid and thorough switching, and provides zero or minimal resistance to the passive motion path. Summary of the Invention

[0004] The technical problem this invention aims to solve is to provide an active-passive switching structure, switching method, knee joint system, and mechanical leg that can efficiently couple or decouple the rotary drive source from the knee joint actuator (especially an optimized knee joint structure that combines a four-bar linkage and a gear constraint chain). This ensures precise and stable power transmission in active mode. In passive mode, it is essential to ensure complete physical disengagement between the drive source (including its inherent resistance) and the knee joint's actuator chain (such as the drive / driven wheel and the driven / driven wheel). This allows the latter to achieve completely free, low-resistance, and smooth passive flexion and extension movements based on the structure's biomechanical characteristics and the user's external force. This truly achieves the goal of using the knee joint as a high-performance passive joint even when "power is off" or when power needs to be conserved, thereby significantly improving the device's environmental adaptability, battery life, and the user's psychological safety and overall fit.

[0005] This invention provides a drive-passive switching structure, including a drive wheel, a transmission wheel II, a driven wheel, a bracket, and a clutch mechanism;

[0006] The driving wheel and the driven wheel are rotatably mounted on the bracket. The driving wheel is used to connect with the rotary drive mechanism, and the driven wheel is used to connect with the drive part of the knee joint structure.

[0007] The clutch mechanism includes an operating part and a locking part. The operating part includes a rotating component rotatably mounted on the axis of the driving wheel and a clutch rod fixedly mounted on the rotating component. The transmission wheel II is rotatably mounted on the clutch rod and is always rotatably engaged with the driving wheel. By rotating the clutch rod, the transmission wheel II is rotatably engaged or disengaged from the driven wheel. The locking part is used to lock the position of the clutch rod to maintain the rotatably engaged or disengaged state of the transmission wheel II and the driven wheel.

[0008] Furthermore, the locking part includes a sliding plate, an elastic element, and a locking connecting rod;

[0009] The slide plate is fixed relative to the bracket. The slide plate is provided with an arc-shaped slide groove, and a slider is slidably disposed on the arc-shaped slide groove. The outer convex side of the arc-shaped slide groove faces the axis of the drive wheel.

[0010] One end of the locking connecting rod is fixed to the rotating part, and the other end intersects with the arc-shaped sliding groove and is located on the concave side of the arc-shaped sliding groove;

[0011] One end of the elastic element is fixed to the slider, and the other end is fixed to the end of the locking connecting rod.

[0012] Furthermore, the two ends of the arc-shaped groove are respectively the connection limit position and the separation limit position;

[0013] When the drive wheel II and the driven wheel change from a separated state to a connected state, the slider actively or passively slides from the separation limit position to the connection limit position.

[0014] Furthermore, the locking part also includes a rotating rod;

[0015] One end of the rotating rod is rotatably mounted on the slide plate, with the axis of rotation located at the center of the arc-shaped slide, and the other end is fixedly connected to the slider.

[0016] Furthermore, the elastic element is a spring.

[0017] Furthermore, this active-passive switching structure also includes a manual operating lever fixed to the rotating component, which is used to manually operate the rotating component to rotate.

[0018] The present invention also provides an active-passive switching method, which uses the above-described active-passive switching structure to switch between active and passive motion, including the following steps:

[0019] During active movement, by controlling the clutch lever, the driving wheel, transmission wheel II, and driven wheel are sequentially engaged. The locking part maintains the engaged state of the driving wheel, transmission wheel II, and driven wheel. At this time, the rotary drive mechanism drives the driving wheel to rotate, and the driving wheel drives the driven wheel to rotate, thus enabling the driven part of the knee joint to be driven.

[0020] During passive movement, by controlling the clutch lever, the transmission wheel II and the driven wheel are separated, and the locking part keeps the transmission wheel II and the driven wheel in a separated state. At this time, the driving part of the knee joint is disconnected from the rotary drive mechanism.

[0021] The present invention also provides a knee joint system, including a knee joint structure and the above-mentioned active-passive switching structure;

[0022] The knee joint structure includes a four-bar linkage and a rotating wheel mechanism;

[0023] The four-bar linkage includes links I, II, III and IV, which are hinged together at the beginning and end. Link I is used to connect the thigh of the mechanical leg and link III is used to connect the lower leg of the mechanical leg.

[0024] The rotating wheel mechanism includes connecting rod V and connecting rod VI, which are hinged to each other. A transmission wheel I is rotatably arranged on the hinge axis of connecting rod V and connecting rod VI. A driving / driven wheel that rotatably engages with the transmission wheel I is rotatably arranged on connecting rod V. The driving / driven wheel is fixed on connecting rod I. A driven / driving wheel that rotatably engages with the transmission wheel I is rotatably arranged on connecting rod VI. The driven / driving wheel is fixed on connecting rod III.

[0025] The axle of the driven wheel in the active-passive switching structure is fixedly connected to the axle of the active / passive wheel or the driven / active wheel.

[0026] Furthermore, this knee joint system also includes a rotation drive mechanism;

[0027] The rotary drive mechanism includes a motor, a gear set, and a bevel gear set;

[0028] The driving gear of the gear set is fixedly engaged with the motor shaft, the driven gear is fixedly connected to the driving bevel gear of the bevel gear set, and the driven bevel gear of the bevel gear set is fixedly connected to the axle of the driving gear.

[0029] The present invention also provides a mechanical leg, the mechanical leg including the above-described knee joint system.

[0030] The beneficial effect of this invention is that the active-passive switching structure is used to achieve rapid switching between active and passive movements of the knee joint structure. After the rotation drive mechanism of the robotic leg loses power, the knee joint structure can be switched to a passive movement state, allowing it to still be used as a passive robotic leg (e.g., a prosthesis). This enables the knee joint structure to combine active and passive dual systems.

[0031] In active mode, high-precision and stable power transmission is achieved by relying on transmission wheels (gears). In passive mode, it can drive in reverse without affecting the movement of the four-bar linkage in the knee joint structure, forming a complete knee joint transmission chain.

[0032] By coupling the active / passive switching structure of this invention with the knee joint structure, the mechanical leg (prosthetic) can still be used as a four-link passive mechanical leg (prosthetic) after the power is depleted, reducing dependence on electricity. Simultaneously, it can actively switch states according to different usage scenarios, saving power and adapting to more situations. This allows for more confident use of the mechanical leg (prosthetic) without battery anxiety, thus improving adaptability. Attached Figure Description

[0033] Appendix Figure 1 This is a schematic diagram of the first angle structure of the knee joint system in this invention;

[0034] Appendix Figure 2 This is a schematic diagram of the second angle structure of the knee joint system in this invention;

[0035] Appendix Figure 3 This is a schematic diagram of the first angle structure of the knee joint in this invention;

[0036] Appendix Figure 4 This is a schematic diagram of the second angle structure of the knee joint in this invention;

[0037] Appendix Figure 5 This is a front view of the knee joint structure at its initial angle in this invention;

[0038] Appendix Figure 6 This is a front view of the knee joint structure in this invention from the middle angle;

[0039] Appendix Figure 7 This is a front view of the ultimate flexion angle of the knee joint structure in this invention;

[0040] Appendix Figure 8 This is a schematic diagram of the dimensions of a four-bar linkage in one embodiment of the present invention;

[0041] Appendix Figure 9 This is a schematic diagram of the motion of the four-bar linkage in this invention;

[0042] Appendix Figure 10 This is a motion curve diagram of the four-bar linkage in this invention;

[0043] Appendix Figure 11 This is a schematic diagram showing the cooperation between the active / passive switching structure and the rotary drive mechanism in this invention;

[0044] Appendix Figure 12 This is a schematic diagram of the active / passive switching structure in this invention;

[0045] Appendix Figure 13 This is a schematic diagram of the connection between the driving wheel and the driven wheel in the active-passive switching structure of the present invention;

[0046] Appendix Figure 14 This is a schematic diagram of the active and passive switching structure in this invention when the active wheel and the driven wheel are separated.

[0047] In the diagram, 1-four-bar linkage; 11-linkage I; 12-linkage II; 13-linkage III; 14-linkage IV; 15-connecting rod I; 16-connecting rod II; 17-connecting rod III; 2-rotating wheel mechanism; 21-linkage V; 22-linkage VI; 23-transmission wheel I; 24-driving / driven wheel; 25-driven / driving wheel; 3-driving / passive switching structure; 31-driving wheel; 32-transmission wheel II; 33-driven wheel; 34-support; 35-rotating component; 36-clutch rod; 37-slide plate; 371-arc slide; 38-elastic component; 39-locking connecting rod; 310-slider; 311-rotating rod; 312-manual operating lever; 4-rotary drive mechanism; 41-motor; 42-gear set; 43-bevel gear set. Detailed Implementation

[0048] 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, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0049] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0050] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0053] As attached Figure 1 - Appendix Figure 14 As shown, the present invention provides a knee joint structure, including a four-bar linkage 1 and a rotating wheel mechanism 2;

[0054] The four-bar linkage 1 includes connecting rods I11, II12, III13 and IV14 that are hinged together from end to end. Connecting rod I11 is used to connect the thigh of the mechanical leg, and connecting rod III13 is used to connect the lower leg of the mechanical leg. That is, the two opposite connecting rods in the four-bar linkage are used to connect the thigh and lower leg of the mechanical leg respectively.

[0055] The rotating wheel mechanism 2 includes connecting rods V21 and VI22, which are hinged to each other. A transmission wheel I23 is rotatably mounted on the hinge axis of connecting rods V21 and VI22. A driving / driven wheel 24, which rotatably engages with the transmission wheel I23, is rotatably mounted on connecting rod V21. The driving / driven wheel 24 is rotatably mounted on connecting rod I11. A driven / driven wheel 25, which rotatably engages with the transmission wheel I23, is rotatably mounted on connecting rod III13. That is, the driving / driven wheel 24, the transmission wheel I23, and the driven / driven wheel 25 mesh sequentially, and their motion trajectories are simultaneously restricted by connecting rods V21, VI22, and the four-bar linkage 1. The driving / driven wheel 24 can be used as the driving wheel, in which case the driven / driven wheel 25 is the driven wheel; conversely, the driving / driven wheel 24 can be used as the driven wheel, in which case the driven / driven wheel 25 is the driving wheel. The driving wheel can be connected to the rotary drive mechanism 4, thereby actively driving the transmission wheel I 23 and the driven wheel to rotate, causing the four-bar linkage 1 to move according to its specific motion trajectory. The driving wheel can also be separated from the rotary drive mechanism 4. In this case, the driving / driven wheel 24, the transmission wheel I 23, and the driven / driven wheel 25 will all be passively rotated by the deformation of the four-bar linkage 1. The driving / driven wheel 24 and the driven / driven wheel 25 are both driving wheels and driven wheels.

[0056] In this invention, the four-bar linkage 1 in the knee joint structure is equivalent to the main chain for structural stability, while the rotating wheel mechanism 2 is equivalent to the secondary chain for speed coordination. It not only achieves or even surpasses the knee joint structure formed by the traditional five-bar linkage and three-gear structure in terms of motion coordination (Chinese Invention Patent CN103976807B - A Prosthetic Knee Joint with a Five-Bar Gear Mechanism), but also demonstrates excellent optimization effects in passive motion stability, structural load-bearing capacity, and modular redundancy design. In contrast, the traditional five-bar linkage and three-gear structure appears singular and fragile in the power interruption state, with its stress mainly borne by the three gears. The concentrated load borne by the three gears is more prone to failure under long-term use or external impact, reducing the safety and reliability of the system.

[0057] Specifically, the traditional five-bar three-gear structure, after the power system fails or disconnects, will experience the following problems due to: a large number of links in a single system (in this invention, the six links are divided into a four-bar system and a two-bar system, forming two independent systems); high degrees of freedom; numerous hinge points and increased friction pairs; and a lack of stabilizing components to constrain the structural position. These problems include: dead-point jamming: multi-bar systems are prone to mechanical dead points at certain angles, lacking inertia and difficult to pass through. Since passive motion has lower inertia than active motion, the traditional five-bar three-gear structure is more prone to dead-point jamming; instability and swaying: redundant degrees of freedom mean that the relative angles of the links cannot be stably maintained after the loss of active control, resulting in structural loosening or swaying; path uncertainty: because the motion trajectory depends on the active force, there is no passive trajectory guidance or closed-loop constraint; and a high risk of user imbalance: users lack control when swinging with only external force, posing a risk of falling due to structural unconstraint. The knee joint structure provided by this invention maintains a synchronous coupling motion relationship between the four-bar linkage 1 and the rotating wheel mechanism 2 after the active force is disconnected, and the system can autonomously maintain a passive motion trajectory. The stability, anti-shaking ability and load balance in the passive state are better, making it suitable for scenarios with high robustness requirements (such as power failure walking, anti-fall, etc.).

[0058] Therefore, the four-bar linkage 1 of this invention constitutes a closed load-bearing path, possessing inherent structural stability. The two-bar linkage plus three-gear system in the rotating wheel mechanism 2 serves to constrain angular velocity, transmit torque, and fine-tune the trajectory. The combination of these two mechanisms distributes the load transmission path, significantly improving the overall structure's impact resistance and ultimate load-bearing capacity. After the main force is disconnected, stable passive gait simulation can be achieved through the coupling of the four-bar linkage 1 and the rotating wheel mechanism 2, significantly outperforming the mechanical instability problem of the five-bar linkage under power-off conditions.

[0059] Furthermore, in traditional gear four-bar linkages, two or three gears are directly rotatably mounted on two or three hinge axes of the four-bar linkage. When applied to the knee joint, its essence is no different from the traditional five-bar three-gear structure. However, this knee joint structure is optimized for the application scenario of the knee joint. In the rotating wheel mechanism 2, the driving / driven wheel 24 and the driven / driving wheel 25 do not necessarily have to be mounted on the hinge axis of the four-bar linkage 1. Moreover, the axis of the transmission wheel I 23 is independent of the four-bar linkage 1, so that it can be coupled and constrained with the four-bar linkage 1, achieving excellent knee joint structure motion coordination, high impact resistance and ultimate load-bearing capacity.

[0060] By designing the dimensions of the four-bar linkage 1 and the rotating wheel mechanism 2, and referring to... Figures 8-10 It can achieve customized trajectories, generating complex, dynamically adjustable curves that closely match the instantaneous center of gravity trajectory of a healthy knee joint, surpassing the fitting capabilities of a pure four-bar linkage. Ultimately, this results in a more natural and efficient gait, with greater adaptability to different terrains such as slopes and stairs.

[0061] It should be noted that in this application, the driving / driven wheel 24, the transmission wheel I 23 and the driven / driven wheel 25 are preferably gears. However, since the four-bar linkage 1 and the rotating wheel mechanism 2 achieve stable passive gait simulation, they can also be friction wheels.

[0062] In one embodiment, a connecting rod is provided on the connecting rod Ⅲ13, the connecting rod including connecting rod Ⅰ15, connecting rod Ⅱ16 and connecting rod Ⅲ17 connected in sequence;

[0063] The connecting rod I15 and the connecting rod III17 are parallel to each other, and one end of the connecting rod I15 is fixed to the connecting rod III13;

[0064] The driven / driving wheel 25 is rotatably mounted at the end of the connecting rod Ⅲ17.

[0065] In this embodiment, by setting up connecting rods, the lower leg of the mechanical leg can be connected via connecting rod I 15 or connecting rod III 17, thereby ensuring that the connection position of the lower leg is relatively far from the four links in the four-bar linkage 1, avoiding compact areas, ensuring the range of motion of the four-bar linkage 1, and facilitating connection with the driven / driving wheel 25. On the other hand, the setting of connecting rods can extend the lever arm and improve torque transmission efficiency.

[0066] In a preferred embodiment, the end of connecting rod III17 is hinged to the end of connecting rod VI22, thereby enabling the four connecting rods in the four-bar linkage 1 and the two connecting rods in the rotating wheel mechanism 2 to be interconnected, which greatly improves the load transmission path of the overall structure, increases the load capacity, and improves the structural stability of the overall structure.

[0067] In one embodiment, the projection of the axis of the driven / driving wheel 25 onto the plane of the four-bar linkage 1 is located on the connecting rod III 13. This arrangement ensures that the motion trajectory of the driven / driving wheel 25 is completely equivalent to that of a wheel directly rotating on the connecting rod III 13, without affecting the coupling between the four-bar linkage 1 and the rotating wheel mechanism 2.

[0068] In one embodiment, the connecting rod I 15 is coplanar with the plane of the four-bar linkage 1, and the driven / driving wheel 25 is located between the connecting rod I 15 and the connecting rod II 16. This arrangement allows for stable and reliable fixing of the driven / driving wheel 25. The two rigid rods, connecting rod I 15 and connecting rod II 16, can form a protective support for the driven / driving wheel 25. Preferably, the driven / driving wheel 25 can be simultaneously connected to the ends of both connecting rod I 15 and connecting rod II 16 opposite to the connecting rod III 13, or the driven / driving wheel 25 can be simultaneously connected to both connecting rod II 16 and connecting rod III 13, making the driven / driving wheel 25 a two-point fixed structure, greatly improving the rotational stability of the driven / driving wheel 25.

[0069] In one embodiment, the drive wheel I 23, the driving / driven wheel 24, and the driven / driving wheel 25 are located between the four-bar linkage 1 and the connecting rod V 21 and the connecting rod VI 22.

[0070] In this embodiment, the three wheels are located between the two sets of rods, making the overall structure compact, and the two sets of rods constitute the physical protection of the wheels.

[0071] In one embodiment, the rotation axis of the driving / driven wheel 24 is coaxial with the hinge axis of the connecting rod I 11 and the connecting rod II 12.

[0072] This design not only ensures complete synchronization between the linkage rotation and gear drive, improving motion consistency and transmission efficiency, but also significantly simplifies the structure, shortens the torque transmission path, better resists bending and deflection torques, and enhances structural rigidity and stability. Especially in passive mode, the structure can stably respond to external forces, avoiding uncontrolled swaying or load transmission imbalance.

[0073] In one embodiment, the length of connecting rod I 11 is 27 mm, the length of connecting rod II 12 is 80 mm, the length of connecting rod III 13 is 45 mm, and the length of connecting rod IV 14 is 45 mm. In this embodiment, reference... Figures 3-10After the four-bar linkage 1 is coupled with the rotating wheel mechanism 2, a specific motion trajectory can be achieved. Using the driving / driven wheel 24 at the hinge axis of link I 11 and link II 12 as the driving wheel, motion trajectory curve simulation reveals that the relative distance between link I 11 and link III 13 during relative motion varies and does not exhibit a linear pattern. This design not only more closely approximates the "rolling + sliding" composite trajectory of the human knee joint during flexion and extension, but also allows for non-uniform torque transmission by controlling the gear ratio and transmission structure. This enables more precise adjustment by the auxiliary intelligent control system, improving the human-machine interaction performance of the prosthesis. The results are as follows... Figure 9 and Figure 10 ( Figure 10 In the diagram, A is the hinge axis between connecting rods III13 and IV14, B is the connection point between connecting rod I15 and II16, and C is the hinge point between connecting rod I11 and II12. This four-bar linkage 1, in conjunction with the rotating wheel mechanism 2, can maintain stable power transmission at any position without slippage or changes due to distance variations, achieving stable power output. Ultimately, this results in a more natural and adaptable gait. Throughout the entire movement, there is no motion interference between the components, resulting in smooth movement without dead points, sudden speed changes, or sudden angle changes.

[0074] In one embodiment, the transmission ratio of the driving / driven wheel 24 and the driven / driven wheel 25 is 1. With this configuration, the gear train transmission ratio is 1 in passive mode. Since both the driving / driven wheel 24 and the driven / driven wheel 25 are free-rotating shafts without external loads, this structure can reverse drive in passive mode, ensuring the availability of passive mode.

[0075] The present invention also provides a knee joint movement method using the above-mentioned knee joint structure, including active knee joint movement and passive knee joint movement;

[0076] The active knee joint movement includes the following steps:

[0077] The power output drives the main / driven wheel 24 or the driven / driving wheel 25 to rotate, and the main / driven wheel 24 or the driven / driving wheel 25 drives the driven / driving wheel 25 or the main / driven wheel 24 to rotate through the transmission wheel I 23;

[0078] At the same time, the four-bar linkage 1 and the rotating wheel mechanism 2 move in coordination, so that the four-bar linkage 1 moves along a specific trajectory;

[0079] The driven knee joint movement includes the following steps:

[0080] The connecting rod I11 or connecting rod III13 moves passively, and during the passive movement, it cooperates with the rotating wheel mechanism 2 to make the four-bar linkage 1 move along a specific trajectory.

[0081] The present invention also provides a mechanical leg, which includes the above-described knee joint structure. The mechanical leg is preferably a prosthesis, thereby enabling passive movement in response to the movement of the human body. It can also be an exoskeleton structure for the human leg.

[0082] The present invention also provides a main-passive switching structure 3, including a driving wheel 31, a transmission wheel II 32, a driven wheel 33, a bracket 34 and a clutch mechanism;

[0083] The driving wheel 31 and driven wheel 33 are rotatably mounted on the bracket 34. The driving wheel 31 is connected to the rotary drive mechanism 4 to drive the active rotation of the driving wheel 31, thereby realizing the active movement of the knee joint structure. The driven wheel 33 is connected to the drive part of the knee joint structure, namely the driving / driven wheel 24 or the driven / driven wheel 25 of the knee joint structure. Figure 1 Driven wheel 33 is connected to driven / driving wheel 25;

[0084] The clutch mechanism includes an operating part and a locking part. The operating part includes a rotating member 35 rotatably mounted on the axis of the driving wheel 31, a clutch lever 36 fixedly mounted on the rotating member 35, and a transmission wheel II 32 rotatably mounted on the clutch lever 36. The transmission wheel II 32 is always rotatably engaged with the driving wheel 31. By rotating the clutch lever 36, the transmission wheel II 32 is rotatably engaged or disengaged from the driven wheel 33. (Reference) Figure 13 When the drive wheel II 32 and the driven wheel 33 are in rotational engagement, the driving wheel 31, the drive wheel II 32, and the driven wheel 33 rotate in sequence, thereby realizing the rotational engagement of the driving wheel 31 and the driven wheel 33. (Refer to...) Figure 14 When the transmission wheel II 32 separates from the driven wheel 33, the driving wheel 31 and the driven wheel 33 disengage from their rotational engagement. At this time, the driven wheel 33 loses its load and becomes a free structure from the driving / driven wheel 24 or driven / driven wheel 25 of the knee joint structure. This enables the passive movement of the four-bar linkage 1 and the rotating wheel mechanism 2 in the knee joint structure.

[0085] The locking part is used to lock the position of the clutch lever 36, maintaining the drive wheel II 32 and the driven wheel 33 in a rotating engaged or disengaged state. This achieves high stability in both active and passive motion.

[0086] This active / passive switching structure 3 is used to achieve rapid switching between active and passive movements of the knee joint structure. After the rotation drive mechanism 4 of the robotic leg loses power, the knee joint structure can be switched to a passive movement state, allowing it to still be used as a passive robotic leg (e.g., a prosthesis). This enables the knee joint structure to combine active and passive movements.

[0087] In active mode, high-precision and stable power transmission is achieved by relying on transmission wheels (gears). In passive mode, it can drive in reverse without affecting the movement of the four-bar linkage 1 in the knee joint structure, forming a complete knee joint transmission chain.

[0088] By coupling the active / passive switching structure 3 of this invention with the knee joint structure, the mechanical leg (prosthetic) can still be used as a four-link passive mechanical leg (prosthetic) after the power is depleted, reducing its dependence on electricity. Simultaneously, it can actively switch states according to different usage scenarios, saving power and adapting to more situations. This allows for more confident use of the mechanical leg (prosthetic) without battery anxiety, thus improving its adaptability.

[0089] In one embodiment, the locking part includes a sliding plate 37, an elastic element 38, and a locking connecting rod 39;

[0090] The slide plate 37 is fixed relative to the bracket 34. The slide plate 37 is provided with an arc-shaped slide groove 371. A slider 310 is slidably disposed on the arc-shaped slide groove 371. The outer convex side of the arc-shaped slide groove 371 faces the axis of the drive wheel 31.

[0091] One end of the locking connecting rod 39 is fixed to the rotating member 35, and the other end intersects with the arc-shaped slide groove 371 and is located on the concave side of the arc-shaped slide groove 371;

[0092] One end of the elastic element 38 is fixed to the slider 310, and the other end is fixed to the end of the locking connecting rod 39.

[0093] In this embodiment, when the rotating component 35 rotates (driving the clutch lever 36, thereby moving the transmission wheel II 32), the locking connecting rod 39 also moves accordingly. Since the other end of the locking connecting rod 39 is on the concave side of the arc-shaped groove and is connected to the slider 310 via the elastic element 38, the slider 310 slides within the arc-shaped groove 371. When the slider 310 slides to the corresponding locking position within the arc-shaped groove 371, the elastic element 38 always provides a pulling force, causing the slider 310 to self-lock in the locking position, thus achieving position locking of the clutch lever 36 and the locking clutch lever 36. This achieves a self-locking stability effect.

[0094] Furthermore, due to the presence of the elastic element 38, when the drive wheel II 32 meshes with the driven wheel 33, the elastic element 38 can provide a certain preload, making the fit between the drive wheel II 32 and the driven wheel 33 tighter and preventing disengagement due to vibration or other reasons. At the same time, during the switching process, the elastic element 38 can absorb impact, making the switching process smooth.

[0095] In addition, in the active drive state, if the driven wheel 33 encounters excessive resistance (such as an accidental impact), the elastic element 38 can deform, allowing the locking connecting rod 39 to have a slight displacement, thereby temporarily separating the transmission wheel II 32 from the driven wheel 33, thus avoiding hard damage to the mechanism.

[0096] In this configuration, the driving wheel 31 and the transmission wheel II 32 are always in a engaged state. This arrangement reduces one clutch component, allowing the transmission wheel II 32 to perform the clutch function simply by connecting and disengaging with the driven wheel 33. This simplifies the complexity of the clutch mechanism, especially in space-constrained scenarios like mechanical legs, improving structural compactness and reliability.

[0097] In one embodiment, the two ends of the arc-shaped groove 371 are the connection limit position and the separation limit position, respectively;

[0098] When the drive wheel II 32 and the driven wheel 33 change from a separated state to a connected state, the slider 310 actively or passively slides from the separation limit position to the connection limit position.

[0099] In this embodiment, the design of the arc-shaped slide 371 allows the slider 310 to move naturally and smoothly without jamming. By configuring the two ends of the arc-shaped slide 371 as two extreme positions, the arc-shaped track of the arc-shaped slide 371 can be used to form a locking point at the end of the arc-shaped slide 371, and the transition can be natural through arc-shaped sliding.

[0100] In one preferred embodiment, the curvature of the arc-shaped groove 371 can be designed to form two adjustment methods:

[0101] One adjustment method involves manually adjusting the clutch lever 36 to switch the drive wheel II 32 and driven wheel 33 from a disengaged state to a connected state, or vice versa. In this case, due to the small curvature of the arc-shaped groove 371, the slider 310 will actively (automatically) slide from the disengagement limit position to the connection limit position, or vice versa. In this way, only one adjustment is needed to achieve the active / passive switching.

[0102] Another adjustment method involves manually adjusting the clutch lever 36 to switch the drive wheel II 32 and driven wheel 33 from a disengaged state to a connected state, or vice versa. Due to the large curvature of the arc-shaped groove 371, the slider 310 cannot actively (automatically) slide from the disengagement limit position to the connection limit position, or vice versa. The switch can only be achieved by manually and passively sliding the slider 310. This requires two adjustments to complete the active-passive switch. When used as a prosthesis, if the battery is low, a first adjustment (keeping the clutch lever 36 in a specific state) allows the user to adapt. If the adaptation is good, the user performs a second adjustment (adjusting the slider 310) to complete the final switch. If the user is unwell and cannot adapt, the clutch lever 36 can be released, keeping the knee joint in its original position, allowing the user to use the remaining battery power to ensure safety and await rescue.

[0103] In one embodiment, the elastic element 38 is a spring. The spring structure is simple and reliable, and it is easy to assemble and disassemble, facilitating adjustment of the elastic force and thus controlling the adjustment sensitivity.

[0104] In one embodiment, the locking part further includes a rotating rod 311;

[0105] One end of the rotating rod 311 is rotatably mounted on the sliding plate 37, with its rotation axis located at the center of the arc-shaped sliding groove 371. The other end is fixedly connected to the slider 310. In this embodiment, by adding the rotating rod 311, the sliding stability of the slider 310 can be improved, thereby enhancing the overall structural reliability.

[0106] In one embodiment, the active-passive switching structure 3 further includes a manual operating lever 312 fixed to the rotating member 35, the manual operating lever 312 being used to manually operate the rotating member 35 to rotate. In this embodiment, the active-passive switching structure 3, through manual switching, is suitable for users to actively control the mechanical leg based on the power supply when it is used as a prosthesis or exoskeleton, thus reducing the number of electrically controlled components.

[0107] The present invention also provides a method for switching between active and passive motion, using the above-described active-passive switching structure 3 to switch between active and passive motion, comprising the following steps:

[0108] During active movement, the clutch lever 36 is controlled. Since the clutch lever 36, rotating component 35, locking connecting rod 39, and manual operating lever 312 are a single unit, any component can be operated. When the manual operating lever 312 is provided, the clutch lever 36 can be controlled via the manual operating lever 312. The driving wheel 31, transmission wheel II 32, and driven wheel 33 are sequentially engaged. The locking part maintains the engaged state of the driving wheel 31, transmission wheel II 32, and driven wheel 33. At this time, the rotary drive mechanism 4 drives the driving wheel 31 to rotate, and the driving wheel 31 drives the driven wheel 33 to rotate. The driven wheel 33 realizes the driving part (driven / driven wheel 25) of the knee joint structure.

[0109] During passive movement, by controlling the clutch lever 36, the transmission wheel II 32 and the driven wheel 33 are separated. The locking part keeps the transmission wheel II 32 and the driven wheel 33 in a separated state. At this time, the driving part (driven / driven wheel 25) of the knee joint structure is disconnected from the rotary drive mechanism 4. The driving part (driven / driven wheel 25) of the knee joint structure is a free end and is not connected to a load, so passive free movement of the knee joint structure can be realized.

[0110] The present invention also provides a knee joint system, including a knee joint structure and the above-mentioned active-passive switching structure 3;

[0111] The knee joint structure includes a four-bar linkage 1 and a rotating wheel mechanism 2;

[0112] The four-bar linkage 1 includes connecting rods I11, II12, III13 and IV14 that are hinged together from end to end. Connecting rod I11 is used to connect the thigh of the mechanical leg, and connecting rod III13 is used to connect the lower leg of the mechanical leg.

[0113] The rotating wheel mechanism 2 includes connecting rods V21 and VI22 that are hinged to each other. A transmission wheel I23 is rotatably mounted on the hinge axis of connecting rods V21 and VI22. A driving / driven wheel 24 that rotatably engages with the transmission wheel I23 is rotatably mounted on connecting rod V21. The driving / driven wheel 24 is rotatably mounted on connecting rod I11. A driven / driven wheel 25 that rotatably engages with the transmission wheel I23 is rotatably mounted on connecting rod VI22. The driven / driven wheel 25 is rotatably mounted on connecting rod III13.

[0114] The axle of the driven wheel 33 of the active-passive switching structure 3 is rotatably connected to the axle of the active / passive wheel 24 or the driven / active wheel 25.

[0115] The working principle and effect of the four-bar linkage 1 and the rotating wheel mechanism 2 provided in this embodiment are as described above.

[0116] This invention combines the active / passive switching structure 3 with the rotating wheel mechanism 2, enabling the switching between active and passive movements of the knee joint structure. This allows the corresponding mechanical leg to continue functioning as a passive mechanical leg (e.g., a prosthesis) even after its power is depleted. Unlike conventional active / passive mechanical legs, the four-bar linkage 1, rotating wheel mechanism 2, and active / passive switching structure 3 provided by this invention achieve a compact size, high stability, and meet the space-constrained installation requirements of the knee joint.

[0117] In one embodiment, the knee joint system further includes a rotation drive mechanism 4;

[0118] The rotary drive mechanism 4 includes a motor 41, a gear set 42, and a bevel gear set 43;

[0119] The driving gear of the gear set 42 is fixedly engaged with the rotating shaft of the motor 41, and the driven gear is fixedly connected to the driving bevel gear of the bevel gear set 43. The driven bevel gear of the bevel gear set 43 is fixedly connected to the axle of the driving wheel 31. This rotary drive mechanism 4 allows the motor 41 to be arranged longitudinally, thereby placing the motor 41 on the upper part of the lower leg or the lower part of the thigh, thus ensuring the knee joint position.

[0120] The present invention also provides a mechanical leg, the mechanical leg including the above-described knee joint system.

[0121] The above description is merely an embodiment and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations, modifications, or alterations to the technical solutions of the present invention without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A passive-active switching structure, characterized in that, It includes a driving wheel (31), a transmission wheel II (32), a driven wheel (33), a bracket (34), and a clutch mechanism; The driving wheel (31) and the driven wheel (33) are rotatably mounted on the bracket (34). The driving wheel (31) is used to connect with the rotary drive mechanism (4), and the driven wheel (33) is used to connect with the drive part of the knee joint structure. The clutch mechanism includes an operating part and a locking part. The operating part includes a rotating component (35) rotatably mounted on the axis of the driving wheel (31), a clutch rod (36) fixedly mounted on the rotating component (35), a transmission wheel II (32) rotatably mounted on the clutch rod (36), and the transmission wheel II (32) is always rotatably engaged with the driving wheel (31). By rotating the clutch rod (36), the transmission wheel II (32) is rotatably engaged or disengaged from the driven wheel (33). The locking part is used to lock the position of the clutch rod (36) to maintain the rotational engagement or disengagement state of the transmission wheel II (32) and the driven wheel (33). The locking part includes a sliding plate (37), an elastic element (38), and a locking connecting rod (39). The slide plate (37) is fixed relative to the bracket (34). An arc-shaped slide groove (371) is provided on the slide plate (37). A slider (310) is slidably provided on the arc-shaped slide groove (371). The convex side of the arc-shaped slide groove (371) faces the axis of the drive wheel (31). One end of the locking connecting rod (39) is fixed to the rotating part (35), and the other end intersects with the arc-shaped slide groove (371) and is located on the concave side of the arc-shaped slide groove (371); One end of the elastic element (38) is fixed to the slider (310), and the other end is fixed to the end of the locking connecting rod (39).

2. The active / passive switching structure as described in claim 1, characterized in that, The two ends of the arc-shaped groove (371) are the connection limit position and the separation limit position, respectively; When the transmission wheel II (32) and the driven wheel (33) change from a separated state to a connected state, the slider (310) actively or passively slides from the separation limit position to the connection limit position.

3. The active / passive switching structure as described in claim 1, characterized in that, The locking part also includes a rotating rod (311). One end of the rotating rod (311) is rotatably mounted on the slide plate (37), and the axis of rotation is located at the center of the arc-shaped slide (371). The other end is fixedly connected to the slider (310).

4. The active / passive switching structure as described in claim 1, characterized in that, The elastic element (38) is a spring.

5. The active / passive switching structure as described in any one of claims 1-4, characterized in that, It also includes a manual operating lever (312) fixed on the rotating member (35), the manual operating lever (312) being used to manually operate the rotating member (35) to rotate.

6. A method for switching between active and passive modes, characterized in that, The active-passive switching structure (3) as described in any one of claims 1-5 is used to switch between active and passive motion, comprising the following steps: During active movement, by controlling the clutch lever (36), the driving wheel (31), transmission wheel II (32) and driven wheel (33) are sequentially engaged. The locking part maintains the engaged state of the driving wheel (31), transmission wheel II (32) and driven wheel (33). At this time, the rotary drive mechanism (4) drives the driving wheel (31) to rotate, and the driving wheel (31) drives the driven wheel (33) to rotate. The driven wheel (33) realizes the driving of the driving part of the knee joint. During passive movement, by controlling the clutch lever (36), the transmission wheel II (32) and the driven wheel (33) are separated. The locking part keeps the transmission wheel II (32) and the driven wheel (33) in a separated state. At this time, the driving part of the knee joint is disconnected from the rotary drive mechanism (4).

7. A knee joint system, characterized in that, Includes the knee joint structure and the active-passive switching structure as described in any one of claims 1-4 (3); The knee joint structure includes a four-bar linkage (1) and a rotating wheel mechanism (2). The four-bar linkage includes connecting rod I (11), connecting rod II (12), connecting rod III (13) and connecting rod IV (14) that are hinged together from end to end. Connecting rod I (11) is used to connect the thigh of the mechanical leg, and connecting rod III (13) is used to connect the lower leg of the mechanical leg. The rotating wheel mechanism (2) includes connecting rod V (21) and connecting rod VI (22) that are hinged to each other. A transmission wheel I (23) is rotatably arranged on the hinge axis of connecting rod V (21) and connecting rod VI (22). A driving / driven wheel (24) that rotates and cooperates with the transmission wheel I (23) is rotatably arranged on connecting rod V (21). The driving / driven wheel (24) is fixed on connecting rod I (11). A driven / driven wheel (25) that rotates and cooperates with the transmission wheel I (23) is rotatably arranged on connecting rod VI (22). The driven / driven wheel (25) is fixed on connecting rod III (13). The axle of the driven wheel (33) of the active-passive switching structure (3) is fixedly connected to the axle of the active / passive wheel (24) or the driven / active wheel (25).

8. The knee joint system as claimed in claim 7, characterized in that, It also includes a rotary drive mechanism (4); The rotary drive mechanism (4) includes a motor (41), a gear set (42), and a bevel gear set (43). The driving gear of the gear set (42) is fixedly engaged with the shaft of the motor (41), the driven gear is fixedly connected to the driving bevel gear of the bevel gear set (43), and the driven bevel gear of the bevel gear set (43) is fixedly connected to the axle of the driving wheel (31).

9. A mechanical leg, characterized in that, The mechanical leg includes the knee joint system as described in any one of claims 7-8.

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