Double-joint continuously variable transmission ratio structure for power prosthetic leg

Abstract

The double-joint continuously variable transmission ratio structure comprises an artificial limb hip joint, a continuously variable transmission power mechanism and an artificial limb knee joint, wherein one end of the continuously variable transmission power mechanism is connected with the artificial limb hip joint, and the other end of the continuously variable transmission power mechanism is connected with the artificial limb knee joint; the continuous variable transmission power mechanism is driven by a power motor to transmit power to the prosthetic hip joint and the prosthetic knee joint at the same time, the prosthetic hip joint is driven to complete hip bending action, the prosthetic knee joint is driven to complete knee bending action, and hip and knee movement coordination is conducted through a speed adjusting motor. Under the action of a single power source, through the structure, the transmission ratio can be changed according to the hip and knee joint movement relation in the gait cycle, the hip and knee cooperation rule in the human body movement process is simulated, and therefore the movement collaboration between artificial leg joints is improved, and the energy conversion efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent prostheses, and in particular to a double-joint continuously variable transmission ratio structure for a powered prosthetic leg. Background Art

[0002] With the development of society and advancements in technology, amputees increasingly desire to regain their ability to perform daily activities and participate in normal social activities. Therefore, the research and design of bionic prostheses is of great significance. Within the current field of lower limb prosthetics, hip disarticulation prostheses are the most challenging to control, resulting in a lack of specialized intelligent prostheses. Furthermore, traditional hip disarticulation prostheses typically design the hip and knee joints as relatively independent components. However, this separate design presents numerous drawbacks. Firstly, during walking, the movement of the hip and knee joints requires a high degree of coordination. Independently designed prostheses struggle to mimic the natural human gait, potentially leading to abnormal walking posture, unstable center of gravity, and increased risk of falls. Secondly, traditional hip prostheses lack active power, requiring the amputee to rely on inertia to swing them outward. This walking style not only consumes significant energy, but also can lead to other health problems if the gait is deformed over time. Furthermore, although studies have explored the feasibility of powered hip prostheses, the independent operation of each joint results in low overall energy transfer efficiency.

[0003] Therefore, technicians in this field are committed to developing a dual-joint continuously variable transmission ratio structure for powered prosthetic legs, which transmits power to the hip and knee joints respectively through gears and realizes continuous change of the dual-joint movement speed ratio to simulate the coordinated changes of the hip and knee joints of a normal human body during walking, so as to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a bionic prosthetic structure that can highly simulate the coordination law of the hip and knee during human movement and improve the coordination of prosthetic joint movement.

[0005] To achieve the above-mentioned object, the present invention proposes a dual-joint continuously variable transmission ratio structure for a powered prosthetic leg, comprising a prosthetic hip joint, a continuously variable transmission power mechanism, and a prosthetic knee joint:

[0006] One end of the continuously variable transmission power mechanism is connected to the prosthetic hip joint, and the other end is connected to the prosthetic knee joint;

[0007] The continuously variable transmission power mechanism includes a frame, a power motor, and a universal joint assembly with a slidable and variable length:

[0008] The frame is equipped with an output gear, a hip joint reduction gear assembly, a sun gear, a knee joint transmission gear and a speed regulating motor;

[0009] The power motor is drivingly connected to the output gear;

[0010] The output gear is respectively in transmission connection with the hip joint reduction gear assembly and the knee joint transmission gear;

[0011] The hip joint reduction gear assembly is in transmission connection with the prosthetic hip joint;

[0012] The knee joint transmission gear is meshed with the sun gear; the sun gear is connected to the prosthetic knee joint through a first bevel gear assembly and a slidable variable-length universal joint assembly, and the hip and knee movements are coordinated through the speed regulating motor;

[0013] The continuously variable transmission power mechanism transmits power to the prosthetic hip joint and the prosthetic knee joint in two directions simultaneously, driving the prosthetic hip joint to complete hip flexion movement and driving the prosthetic knee joint to complete knee flexion movement.

[0014] Furthermore, the prosthetic hip joint includes a support plate, a hip joint hydraulic buffer module and a damping motor:

[0015] The support plate is rotatably connected to the Y-shaped short connecting rod and the long connecting rod respectively through the hip joint connector;

[0016] The Y-shaped short connecting rod is slidably connected to the top of the frame and is rotatably connected to the hip joint hydraulic buffer module; the hip joint hydraulic buffer module is a damping adjustable hydraulic buffer module, fixed to the frame, and the end is meshedly connected to the first module gear; the damping motor is fixed to the frame through a motor support and is connected to the first module gear;

[0017] The long connecting rod is flexibly connected to the flexible gear through a linear spring, the flexible gear is meshed and connected to the transmission gear, and the transmission gear is transmission-connected to the hip joint reduction gear assembly.

[0018] Furthermore, in the continuously variable transmission power mechanism, the hip joint reduction gear assembly includes a meshed hip joint primary reduction gear and a hip joint secondary reduction gear;

[0019] The hip joint secondary reduction gear is connected to the prosthetic hip joint through meshing transmission;

[0020] The hip joint primary reduction gear is meshed with the output gear; the output gear is connected to the sun gear through the knee joint transmission gear;

[0021] The pinion at one end of the sun gear is rotatably connected to the outer ring of the planetary gear and meshes with the planetary gear, and the other end is detachably connected to the large gear;

[0022] The first bevel gear assembly includes an input bevel gear and an output bevel gear with vertically meshed tooth profiles;

[0023] The slidable and variable-length universal joint assembly includes a leg bone tube and a spline assembly. One end of the leg bone tube is connected to the end of the frame through an elbow joint, and the other end is connected to the prosthetic knee joint through a straight joint, so that the length of the leg bone tube can be adjusted.

[0024] The spline assembly includes a spline rod and a spline sleeve that are slidably connected.

[0025] One end of the spline rod is connected to the input end universal joint, and the other end is connected to the output end universal joint; the spline sleeve is fixedly connected to the output end universal joint;

[0026] The planetary gear is fixedly connected to the input bevel gear through the planetary carrier; the output bevel gear is fixedly connected to the input end universal joint.

[0027] The outer ring of the planetary gear of the planetary gear is sleeved with a turbine, the turbine is meshed with the tooth profile of the worm, the worm is meshed with the output gear of the speed regulating motor through the worm gear, and the output gear of the speed regulating motor is drivingly connected to the speed regulating motor.

[0028] Furthermore, the continuously variable transmission power mechanism also includes a gear shaft support cover, a sun gear shaft support cover and a worm support, and the gear shaft support cover is fixedly connected to the frame by screws; the gear shaft support cover provides rotational support for the hip joint secondary reduction gear, hip joint primary reduction gear and knee joint transmission gear through a rib bearing; the sun gear shaft support cover is fixedly connected to the frame by screws, and the sun gear support cover provides rotational support for the sun gear gear through a rib bearing; the worm support is fixedly connected to the frame by screws, and provides rotational support for the worm through a rib bearing.

[0029] Furthermore, the prosthetic knee joint includes a knee joint connector, a knee-leg frame, a calf tube, a knee joint hydraulic buffer module and a knee joint gear:

[0030] The knee joint connector is provided at the end of the continuously variable transmission power mechanism; a second bevel gear assembly is installed on the side of the knee joint connector, one end of the second bevel gear assembly is connected to the universal joint assembly, and the other end is connected to the knee joint connector;

[0031] One end of the knee-leg frame is rotatably connected to the knee joint connector via a long knee joint rod and a short knee joint rod, and the other end is fixedly connected to the calf tube via a knee square taper joint and a knee straight tube joint in sequence;

[0032] A knee damping motor is installed on the knee-leg frame via a knee damping motor support;

[0033] The knee joint hydraulic buffer module is threadedly fixed inside the knee leg frame and is in frictional contact with the knee joint short rod through steel balls. The knee joint hydraulic buffer module is provided with a second module gear, which is meshed and connected to the knee gear. The knee gear is driven and connected to the knee damping motor.

[0034] Furthermore, the frame is provided with a slide groove, a battery slot and a hip square cone joint from top to bottom in sequence; the slide groove is used to fix the Y-shaped short connecting rod; the battery slot is used to install the battery; and the hip square cone joint is used to connect the slidable and variable-length universal joint combination.

[0035] Furthermore, the continuously variable transmission power mechanism transmits power simultaneously in two directions of the prosthetic hip joint and the prosthetic knee joint through the power motor. The transmission ratio of the power motor to the flexible gear in the direction of the prosthetic hip joint is 9:1, and the transmission ratio of the power motor to the sun gear in the direction of the prosthetic knee joint is 3:2.

[0036] Furthermore, when the speed regulating motor is not working, the worm wheel and the worm are self-locked to fix the outer ring of the planetary gear, and the transmission ratio of the sun gear gear to the input bevel gear is 4:1. When the speed regulating motor is controlled to rotate, the transmission ratio of the sun gear gear to the input bevel gear is between 9:2 and -9:2, and the negative sign indicates reverse rotation; when the outer ring of the planetary gear and the sun gear rotate at the same speed and in the opposite direction, the input bevel gear is in a disconnected state after having no power, and the overall transmission ratio i of the prosthetic hip joint and the prosthetic knee joint is continuously variable and satisfies: -2≤i≤2, so as to simulate the general movement law of the lower limb hip and knee joints.

[0037] Compared with the prior art, the advantages of the present invention are:

[0038] 1. The present invention transmits power to the hip and knee joints respectively through gears and realizes continuous change of the speed ratio of the two joints to simulate the coordinated change law of the hip and knee joints of a normal human body during walking. Under the action of a single power source, the transmission ratio can be changed according to the movement relationship of the hip and knee joints in the gait cycle to simulate the hip and knee coordination law during human movement, thereby improving the movement coordination between the joints of the prosthetic leg and improving the energy conversion efficiency. It solves the problems of no coordination between the hip and knee joints and low transmission efficiency in the prior art, reduces the patient's movement load, and improves the user experience effect.

[0039] 2. The present invention provides a speed regulating motor and a worm assembly, which can freely adjust the damping according to the user's walking habits, thereby avoiding the possible jerking feeling that may occur during the periodic movement of rigid transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1This is a side view of the overall appearance of a prosthetic limb with a dual-joint continuously variable transmission ratio structure for a powered prosthetic leg according to the present invention, showing the layout of the three major components;

[0041] Figure 2 This is a perspective view of the overall appearance of a prosthetic limb with a dual-joint continuously variable transmission ratio structure for a powered prosthetic leg according to the present invention, illustrating the connection relationship and position of various components;

[0042] Figure 3 A schematic diagram of a prosthetic overall transmission system of a power prosthetic leg with a dual-joint continuously variable transmission ratio structure according to the present invention, showing the overall transmission layout;

[0043] Figure 4 This is an exploded view of a continuously variable transmission ratio structure of a dual-joint continuously variable transmission ratio structure for a powered prosthetic leg according to the present invention, illustrating the principle of continuously variable transmission;

[0044] Figure 5 This is a diagram of an integrated prosthetic frame with a double-joint continuously variable transmission ratio structure for a powered prosthetic leg according to the present invention;

[0045] Figure 6 This is an internal diagram of a hip joint flexible gear with a dual-joint continuously variable transmission ratio structure for a powered prosthetic leg according to the present invention, illustrating the placement of the flexible element.

[0046] 101-Support plate, 102-Long connecting rod, 103-Connecting head, 104-Y-type short connecting rod, 105-First motor support, 106-First module gear, 107-Flexible gear, 108-Hip transmission gear, 109-Hip joint hydraulic buffer module, 110-First module motor, 111-Linear spring, 201-Gear shaft support cover, 202-Sun gear shaft support cover, 203-Worm support, 204-Leg bone tube, 205-Integrated frame, 205-1-Slide, 205-2-Battery slot, 205-3-Hip square taper joint, 206-Speed ​​regulating motor support, 207-Elbow joint, 208-Straight pipe joint, 209-Hip joint secondary reduction gear, 210-Output gear, 211-Knee joint transmission gear, 212-Hip joint primary reduction gear, 213-Power motor, 214-Bevel gear support seat , 215-speed regulating motor, 216-spline rod, 217-spline sleeve, 218-output end universal joint, 219-planet gear outer ring, 220-first input bevel gear, 221-planet gear, 222-first output bevel gear, 223-speed regulating motor flange, 224-input end universal joint, 225-planet carrier, 226-sun gear, 227-worm gear, 228-worm, 229-worm gear Wheel, 230-speed regulating motor output gear, 301-knee joint connector, 302-knee joint long rod, 303-knee joint straight pipe joint, 304-second bevel gear support, 305-knee leg frame, 306-knee square taper joint, 307-calf tube, 308-knee joint short rod, 309-knee damping motor support, 310-second module gear, 311-knee joint hydraulic buffer module, 312-knee damping motor. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described below.

[0048] This embodiment provides a dual-joint continuously variable transmission ratio structure for a powered prosthetic leg, comprising a prosthetic hip joint 1, a continuously variable transmission power mechanism 2, and a prosthetic knee joint 3. Figure 1 As shown, the top of the continuously variable transmission power mechanism 2 is connected to the prosthetic hip joint 1, and the end is connected to the prosthetic knee joint 3; when the continuously variable transmission power mechanism 2 transmits power to the prosthetic hip joint 1 and the prosthetic knee joint 3 in two directions at the same time, it drives the prosthetic hip joint 1 to complete the hip flexion movement, and drives the prosthetic knee joint 3 to complete the knee flexion movement.

[0049] In this embodiment, Figure 2-4 As shown, the continuously variable transmission power mechanism 2 includes a prosthesis integrated frame 205, a power motor 213, and a universal joint assembly that can slide and change length:

[0050] Among them, Figure 5As shown, the frame 205 is provided with a slide slot 205-1, a battery slot 205-2 and a hip square cone joint 205-3 in sequence from top to bottom.

[0051] The frame 205 is equipped with an output gear 210, a hip joint reduction gear assembly, a knee joint first-stage reduction sun gear gear 226, a knee joint transmission gear 211, a first bevel gear combination, a speed regulating motor 215, a sliding and variable-length universal joint combination, a gear shaft support cover 201, a sun gear shaft support cover 202 and a worm support 203.

[0052] Among them, the gear shaft support cover 201 is fixedly connected to the frame 205 by screws; the gear shaft support cover 201 provides rotational support for the hip joint reduction gear assembly and the knee joint transmission gear 211 through the rib bearing; the sun gear shaft support cover 202 is fixedly connected to the frame 205 by screws, the sun gear support cover 202 is rotationally connected to the sun gear gear 226, and provides rotational support for the sun gear gear 226 through the rib bearing;

[0053] The power motor 213 is drivingly connected to the output gear 210;

[0054] The output gear 210 is in transmission connection with the hip joint reduction gear assembly and the knee joint transmission gear 211 respectively;

[0055] The hip joint reduction gear assembly is connected to the prosthetic hip joint 1 for transmission;

[0056] The knee joint transmission gear 211 is meshed with the sun gear 226 ; the sun gear 226 is connected to the prosthetic knee joint 3 through a first bevel gear combination and a slidable variable-length universal joint combination, and coordinates the hip and knee movements through the speed regulating motor 215 .

[0057] In this embodiment, the hip joint reduction gear assembly includes a meshing hip joint primary reduction gear 212 and a hip joint secondary reduction gear 209; wherein the hip joint secondary reduction gear 209 is meshedly connected with the hip transmission gear 108 of the prosthetic hip joint 1;

[0058] The hip joint primary reduction gear 212 is meshed with the output gear 210; the output gear 210 is meshed with the knee joint transmission gear 211, and the knee joint transmission gear 211 is meshed with the sun gear 226. Figure 4 As shown, the small gear at one end of the sun gear 226 is rotatably connected to the planetary gear outer ring 219 and meshes with the planetary gear 221, and the other end is connected to the large gear, which is detachably fixedly connected to the small gear end through a D-shaped shaft and a retaining ring groove.

[0059] In this embodiment, the first bevel gear assembly includes a first input bevel gear 220 (also known as a knee joint secondary reduction input bevel gear) and a first output bevel gear 222 with vertically meshed tooth profiles;

[0060] The slidable and variable-length universal joint combination includes a femoral tube 204 and a spline assembly. One end of the femoral tube 204 is screwed to the hip square cone joint 205-3 of the frame 205 through a bend pipe joint 207, and the other end is screwed to the prosthetic knee joint 3 through a straight pipe joint 208, so as to achieve personalized adaptation for the patient by changing the length of the femoral tube 204 itself.

[0061] The spline assembly includes a slidingly connected spline rod 216 and a spline sleeve 217. The spline rod 216 and the leg bone tube 204 are vertically juxtaposed. One end of the spline rod 216 is connected to the input end universal joint 224 through a pin, and a retaining spring is provided on the periphery of the pin to prevent the pin from falling off. The input end universal joint 224 is fixedly connected to the first output bevel gear 222 through a shaft, and its shaft is fixedly connected to the bevel gear support seat 214 through a bearing. The input end universal joint 224 and the bevel gear support seat 214 are in contact through a plane pressure bearing to reduce rotational friction. The bevel gear support seat 214 is fixedly connected to the integrated frame 205 with screws.

[0062] The other end of the spline rod 216 is connected to the output end universal joint 218; the spline sleeve 217 and the output end universal joint 218 are fixedly connected by a pin; the output end universal joint 218 is fixedly connected to the second bevel gear support 304 in the same fixing manner.

[0063] In addition, if Figure 4 As shown, the evenly distributed planetary gears 221 are fixedly connected to the planetary carrier 225 through bearing screws, and are fixedly connected to the first input bevel gear 220 through the planetary carrier 225; the planetary carrier 225 is fixedly connected to the first input bevel gear 220 through a retaining ring groove and a D-shaped shaft; the first output bevel gear 222 is fixedly connected to the input end universal joint 224 through a retaining ring groove and a D-shaped shaft, and the first output bevel gear 222 is fixedly connected to the frame 205 through a bevel gear support seat 214, and the bevel gear support seat 214 is fixed to the frame 205 through screws and provides rotational support for the output bevel gear 222.

[0064] Meanwhile, the planetary gear outer ring 219 of the planetary gear 221 is screwed onto the turbine 227. The turbine 227 meshes with the tooth profile of the worm 228. The worm support 203 is fixedly connected to the frame 205 via screws, and a flange bearing provides rotational support for the worm 228. The worm 228 is fixedly connected to the worm gear 229 via a retaining spring groove and a D-shaped shaft. The worm gear 229 also meshes with the speed control motor output gear 230. The speed control motor output gear 230 is fixedly connected to the speed control motor flange 223 via a retaining spring groove and a D-shaped shaft. The speed control motor flange 223 is fixedly connected to the speed control motor 215 via screws, establishing a driving connection between the speed control motor output gear 230 and the speed control motor 215. The speed control motor 215 is screwed to the frame 205 via the speed control motor support 206.

[0065] In this embodiment, Figure 2 As shown, the prosthetic hip joint 1 includes a support plate 101, a long connecting rod 102 symmetrically distributed on both sides, a flexible gear 107 symmetrically distributed on both sides, a transmission gear 108 symmetrically distributed on both sides, a hip joint connector 103, a hip joint hydraulic buffer module 109 and a first module motor 110. Among them, the support plate 101 is bolted to the hip joint connector 103, and the hip joint connector 103 is rotationally connected to the Y-shaped short connecting rod 104 and the long connecting rod 102 respectively through an axis connection; the Y-shaped short connecting rod 104 is slidably connected to the frame slide 205-1 through an axis connection, and is rotationally connected to the hip joint hydraulic buffer module 109 through an axis connection; the hip joint hydraulic buffer module 109 is a damping adjustable hydraulic buffer module, which is connected to the Y-shaped short connecting rod 104 through a T-shaped sleeve joint, and is fixed to the frame 205 through threaded holes and screws, When the hip joint hydraulic buffer module 109 is engaged with the first module gear 106, the end thereof is screwed to the frame 205 through the first motor support 105, and is fixed with the first module gear 106 by screws to realize drive connection; the long connecting rod 102 is rotationally connected to the frame 205 through the shaft and the pressure plate bearing, and the long connecting rod 102 is flexibly connected to the flexible gear 107 through the pressure plate bearing and the linear spring 111, and the flexible gear 107 is engaged with the hip transmission gear 108, and the hip transmission gear 108 is transmission-connected to the hip joint reduction gear assembly.

[0066] In this embodiment, the prosthetic knee joint 3 includes a knee joint connector 301, a knee-leg frame 305, a calf tube 307, a knee joint hydraulic buffer module 311, and a knee joint gear 310.

[0067] Among them, the knee joint connector 301 is fixed to the end of the straight pipe connector 208 by screws; a second bevel gear combination is installed on the side of the knee joint connector 301 through a second bevel gear support 304. The structural layout of the second bevel gear combination is the same as the above-mentioned first bevel gear combination, and is composed of a pair of vertically meshing bevel gears, one of which is fixedly connected to the knee joint long rod 302 through a D-shaped shaft and a retaining spring, and the other is fixedly connected to the output end universal joint 218 through a D-shaped shaft and a retaining spring. The structural layout is consistent with the structure of the first output bevel gear 222 and the first input bevel gear 220.

[0068] like Figure 2 As shown, both ends of the knee joint rod 302 are rotatably connected to the knee joint connector 301 and the knee leg frame 305 through shafts respectively;

[0069] One end of the knee-leg frame 305 is rotationally connected to the knee joint connector 301 through the knee joint long rod 302 and the knee joint short rod 308, and the other end is fixedly connected to the calf tube 307 through the knee square taper joint 306 and the knee joint straight tube joint 303 in turn; wherein, the knee joint straight tube joint 303 is fixedly connected to the knee square taper joint 306 and the calf tube 307 through screws, and the knee joint short rod 308 is rotationally connected to the knee joint connector 301 and the knee-leg frame 305 through an axis.

[0070] A knee joint hydraulic buffer module 311 is fixedly connected to the inside of the knee-leg frame 305 via threads, and the buffer module 311 is fixed by top screws on the side of the knee-leg frame 305. The buffer module 311 is in friction contact with the knee joint short rod 308 via balls.

[0071] At the same time, a knee damping motor support 309 is installed on the knee leg frame 305 by screws, and a knee damping motor 312 is installed through the knee damping motor support 309; the knee damping motor 312 is fixedly connected to the knee gear 310 by screws; the knee joint hydraulic buffer module 311 is in rolling friction contact with the steel column groove at the end of the knee joint short rod 308 through steel balls, and a second module gear is provided at the end of the knee joint hydraulic buffer module 311, and the second module gear is meshed and connected to the knee gear 310, and the knee gear 310 and the knee damping motor 312 are driven and connected.

[0072] When the user is crossing obstacles or performing tasks such as climbing slopes and stairs, the prosthesis can be selected in high-performance mode. At this time, the power motor 213 will work at the rated maximum output power. The power motor 213 transmits power to both the hip and knee directions through the output gear 210. In the direction of the prosthetic hip joint 1, the motor power 213 transmits power to the flexible gear 107 along the hip joint primary reduction gear 212 and the hip joint secondary reduction gear 209. The flexible gear 107 transmits torque to the prosthetic hip joint 1 through the linear coil spring 111 set inside the gear. The long connecting rod 102 drives the hip joint structure to complete the hip flexion movement. In the direction of the prosthetic knee joint 3, the motor power 213 transmits power to the prosthetic knee joint 3 through the sliding variable-length universal joint combination along the knee joint primary reduction sun gear 226 and the knee joint secondary reduction input bevel gear 220 to complete the knee flexion movement. In addition, during the swinging period of the prosthesis, the knee joint needs to complete the flexion and extension movements at the same time. Therefore, the speed regulating motor 215 works at the intermediate moment to enable the knee joint to complete the extension movement until the prosthesis leg lifting movement intention is detected again and the next cycle is entered.

[0073] In this embodiment, the operating mechanism of the speed-regulating motor 215 is as follows: the real-time detection of the hip and knee motion positions is performed by sensors (for example, a rotation angle sensor and a posture sensor are placed on the gear 107 in the hip joint 1 and the connecting rod 302 in the knee joint 3), and the data is uploaded to the central processing unit. According to the relevant algorithm, the instructions are transmitted to control the rotation speed and direction of the motor 215, thereby achieving a continuously variable speed ratio between the hip and knee. For example, in the early stage of swing, if the speed-regulating motor is not working, the knee joint will flex when the hip joint flexes, and the hip-knee transmission ratio is fixed at this time. In the middle stage of swing, the speed-regulating motor intervenes to control its speed and direction, so that the knee joint achieves the output reversal and thus the extension effect under the fusion input power, at which time the hip flexes and the knee extends.

[0074] The prosthetic structure provided in this embodiment simultaneously restores the movement mechanism of the hip and knee joints of the lower limbs, and successfully achieves the flexibility of the swing phase and the stability of the stance phase of the hip and knee joint prostheses through a four-bar linkage structure. According to the kinematic law of flat-ground walking of the lower limb hip and knee joints, the overall reduction ratio i of the prosthetic knee joint 3 and the prosthetic hip joint 1 should satisfy: -2≤i≤2. In addition, in the example, the reduction levels of the prosthetic hip joint 1 and the prosthetic knee joint 3 are both 2 levels. The purpose is to flex the hip joint and flex the knee joint at the same time when the power motor 213 is in a single direction and the speed regulating motor 215 is not working. Therefore, in the design, the reduction levels of the prosthetic hip joint 1 and the prosthetic knee joint 3 should be consistent to avoid the situation where the movement direction of the prosthetic hip joint 1 and the prosthetic knee joint 3 is inconsistent with the direction of most of the joint movement of the normal lower limb hip and knee joints, thereby causing high energy consumption. The remaining situations where the joint movement directions of the hip and knee are different are coordinated by the speed regulating motor 215.

[0075] In this embodiment, the continuously variable transmission power mechanism 2 transmits power simultaneously in two directions, namely, the prosthetic hip joint 1 and the prosthetic knee joint 3, through the power motor 213. The transmission ratio of the power motor 213 to the flexible gear 107 in the direction of the prosthetic hip joint 1 is 9:1, and the transmission ratio of the power motor 213 to the sun gear 226 in the direction of the prosthetic knee joint 3 is 3:2.

[0076] When the speed regulating motor 215 is not working, the worm gear 227 and the worm 228 are self-locked to fix the outer ring of the planetary gear 219, and the transmission ratio of the sun gear 226 to the input bevel gear is 4:1. When the speed regulating motor is controlled to rotate, the transmission ratio of the sun gear to the input bevel gear is between 9:2 and -9:2, and the negative sign indicates reverse rotation; when the outer ring of the planetary gear and the sun gear rotate at the same speed and in opposite directions, the first input bevel gear 220 is in a disconnected state after being unpowered, and the overall transmission ratio i of the prosthetic hip joint 1 and the prosthetic knee joint 3 is continuously variable and satisfies: -2≤i≤2, so as to simulate the general movement law of the lower limb hip and knee joints 3.

[0077] When the user is strolling or walking on a regular flat surface, power motor 213 provides power to prosthetic hip joint 1, and the power provided is only used to overcome the gravitational torque generated by the prosthesis's own weight. The power transmission path of prosthetic hip joint 1 is the same as in the performance mode. The power transmission path of prosthetic knee joint 3 changes continuously, and the speed of the prosthetic knee joint 3 in this mode changes continuously. Therefore, in this mode, power motor 213 only needs to provide general power to reflect the coordinated movement of the hip and knee, which helps to simulate a natural walking gait while reducing the user's physical energy consumption.

[0078] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any person skilled in the art who, without departing from the scope of the present invention, makes any equivalent substitution, modification, or other changes to the technical solution and technical content disclosed in the present invention shall be deemed to be within the scope of the present invention and still fall within the scope of protection of the present invention.

Claims

1. A dual-joint continuously variable transmission ratio structure for a powered prosthetic leg, characterized in that: Including prosthetic hip joints, continuously variable transmission power mechanisms and prosthetic knee joints: One end of the continuously variable transmission power mechanism is connected to the prosthetic hip joint, and the other end is connected to the prosthetic knee joint; The continuously variable transmission power mechanism includes a frame, a power motor, and a universal joint assembly with a slidable and variable length: The frame is equipped with an output gear, a hip joint reduction gear assembly, a sun gear, a knee joint transmission gear, a sun gear and a speed regulating motor; The power motor is drivingly connected to the output gear; The output gear is respectively in transmission connection with the hip joint reduction gear assembly and the knee joint transmission gear; The hip joint reduction gear assembly is in transmission connection with the prosthetic hip joint; The knee joint transmission gear is meshed with the sun gear; the sun gear is connected to the prosthetic knee joint through a first bevel gear assembly and a slidable variable-length universal joint assembly, and the hip and knee movements are coordinated through the speed regulating motor; The continuously variable transmission power mechanism transmits power to the prosthetic hip joint and the prosthetic knee joint in two directions simultaneously, driving the prosthetic hip joint to complete hip flexion movement and driving the prosthetic knee joint to complete knee flexion movement.

2. The double-joint continuously variable transmission ratio structure for a powered prosthetic leg according to claim 1, characterized in that: The prosthetic hip joint includes a support plate, a hip joint hydraulic buffer module and a damping motor: The support plate is rotatably connected to the Y-shaped short connecting rod and the long connecting rod respectively through the hip joint connector; The Y-shaped short connecting rod is slidably connected to the top of the frame and is rotatably connected to the hip joint hydraulic buffer module; the hip joint hydraulic buffer module is a damping adjustable hydraulic buffer module, which is fixed to the frame and has a first module gear engaged at the end; the damping motor is fixed to the frame through a motor support and is connected to the first module gear; The long connecting rod is flexibly connected to the flexible gear through a linear spring, the flexible gear is meshed and connected to the transmission gear, and the transmission gear is transmission-connected to the hip joint reduction gear assembly.

3. The double-joint continuously variable transmission ratio structure for a powered prosthetic leg according to claim 1, characterized in that: In the continuously variable transmission power mechanism, the hip joint reduction gear assembly includes a meshed hip joint primary reduction gear and a hip joint secondary reduction gear; The hip joint secondary reduction gear is connected to the prosthetic hip joint through meshing transmission; The hip joint primary reduction gear is meshed with the output gear; the output gear is connected to the sun gear through the knee joint transmission gear; The pinion at one end of the sun gear is rotatably connected to the outer ring of the planetary gear and meshes with the planetary gear, and the other end is detachably connected to the large gear; The first bevel gear assembly includes an input bevel gear and an output bevel gear with vertically meshed tooth profiles; The slidable and variable-length universal joint assembly includes a leg bone tube and a spline assembly. One end of the leg bone tube is connected to the end of the frame through an elbow joint, and the other end is connected to the prosthetic knee joint through a straight joint, so that the length of the leg bone tube can be adjusted. The spline assembly includes a spline rod and a spline sleeve that are slidably connected. One end of the spline rod is connected to the input end universal joint, and the other end is connected to the output end universal joint; the spline sleeve is fixedly connected to the output end universal joint; The planetary gear is fixedly connected to the input bevel gear through the planet carrier; the output bevel gear is fixedly connected to the input end universal joint; The outer ring of the planetary gear of the planetary gear is sleeved with a turbine, the turbine is meshed with the tooth profile of the worm, the worm is meshed with the output gear of the speed regulating motor through the worm gear, and the output gear of the speed regulating motor is drivingly connected to the speed regulating motor.

4. The double-joint continuously variable transmission ratio structure for a powered prosthetic leg according to claim 3, characterized in that: The continuously variable transmission power mechanism also includes a gear shaft support cover, a sun gear shaft support cover and a worm support, the gear shaft support cover is fixedly connected to the frame by screws; the gear shaft support cover provides rotational support for the hip joint secondary reduction gear, hip joint primary reduction gear and knee joint transmission gear through a rib bearing; the sun gear shaft support cover is fixedly connected to the frame by screws, and the sun gear support cover provides rotational support for the sun gear gear through a rib bearing; the worm support is fixedly connected to the frame by screws, and provides rotational support for the worm through a rib bearing.

5. The double-joint continuously variable transmission ratio structure for a powered prosthetic leg according to claim 1, characterized in that: The prosthetic knee joint includes a knee joint connector, a knee-leg frame, a calf tube, a knee joint hydraulic buffer module and a knee joint gear: The knee joint connector is provided at the end of the continuously variable transmission power mechanism; a second bevel gear assembly is installed on the side of the knee joint connector, one end of the second bevel gear assembly is connected to the universal joint assembly, and the other end is connected to the knee joint connector; One end of the knee-leg frame is rotatably connected to the knee joint connector via a long knee joint rod and a short knee joint rod, and the other end is fixedly connected to the calf tube via a knee square taper joint and a knee straight tube joint in sequence; A knee damping motor is installed on the knee-leg frame via a knee damping motor support; The knee joint hydraulic buffer module is threadedly fixed inside the knee leg frame and is in frictional contact with the knee joint short rod through steel balls. The knee joint hydraulic buffer module is provided with a second module gear, which is meshed and connected to the knee gear. The knee gear is driven and connected to the knee damping motor.

6. The double-joint continuously variable transmission ratio structure for a powered prosthetic leg according to claim 2, characterized in that: The frame is provided with a slide slot, a battery slot and a hip square cone joint in sequence from top to bottom.

7. The double-joint continuously variable transmission ratio structure for a powered prosthetic leg according to claim 2, characterized in that: The continuously variable transmission power mechanism transmits power simultaneously in two directions, namely, the prosthetic hip joint and the prosthetic knee joint, through the power motor. The transmission ratio of the power motor to the flexible gear in the direction of the prosthetic hip joint is 9:1, and the transmission ratio of the power motor to the sun gear in the direction of the prosthetic knee joint is 3:

2.

8. The double-joint continuously variable transmission ratio structure for a powered prosthetic leg according to claim 3, characterized in that: When the speed regulating motor is not working, the worm wheel and the worm are self-locked to fix the outer ring of the planetary gear, and the transmission ratio of the sun gear gear to the input bevel gear is 4:

1. When the speed regulating motor is controlled to rotate, the transmission ratio of the sun gear gear to the input bevel gear is between 9:2 and -9:2, and the negative sign indicates reverse rotation; when the outer ring of the planetary gear and the sun gear rotate at the same speed and in the opposite direction, the input bevel gear is in a disconnected state after having no power, and the overall transmission ratio i of the prosthetic hip joint and the prosthetic knee joint is continuously variable and satisfies: -2≤i≤2, so as to simulate the general movement law of the lower limb hip and knee joints.

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