Compact active prosthesis knee joint with torque regulation

Abstract

The application relates to a compact active artificial knee joint with a torque adjusting device, which comprises a knee joint module, a receiving cavity connecting block, a lower leg connecting piece and a torque adjusting device, wherein the torque adjusting device comprises a spiral spring, a bent spring groove and the like, the knee joint module comprises a knee joint shell, a knee joint shaft center, a knee joint stator sleeve end cover and the like, one end of the spring is fixed at the upper receiving cavity connecting lug through an opening on the motor stator sleeve end cover, and the other end is fixed in the bent spring groove at the position of the motor stator sleeve end cover and the knee joint shaft center. The torque adjusting device can realize torque assistance and adjustment according to the angle size and direction of the limb rotation; meanwhile, the driving peak torque of the motor can be reduced, the size and the maximum torque of the driving motor are smaller due to the fact that the artificial limb needs to be easily worn, energy consumption and space are saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of knee prosthesis, in particular to a compact active prosthesis knee joint with torque adjusting device. BACKGROUND

[0002] In recent years, biped walking robots have become a hot spot in the field of robots. Walking robots not only have broad application scenarios in medical care, old and disabled assistance, etc., but also have good environmental adaptability and strong motion coordination ability, and can study human walking mechanism, so as to better study prosthesis knee joints and better serve humans.

[0003] Knee joints can be divided into active knee joint prosthesis, passive knee joint prosthesis and active-passive knee joint prosthesis according to whether human can provide active torque. Among them, the active knee joint prosthesis which is applied more often needs a power source (motor) to provide main or all torque for the flexion and extension of the knee joint. Therefore, this kind of active knee joint prosthesis is often designed to be large in size and mass, and high in cost, which is not easy for mass production and flowing into the market to be favored by consumers. Therefore, further research on knee joints needs to adopt the method of mechanism design or control to reduce the peak torque of the motor as much as possible. SUMMARY

[0004] The present application aims at the defects of the prior art, and provides a compact active prosthesis knee joint with torque adjusting device, so as to adjust the torque of joint driving, reduce the peak value and increase the valley value, so that a motor with smaller power and maximum torque can be selected, the self-weight of the joint mechanism is reduced, the energy consumption is saved, or the driving torque of the prosthesis wearer is reduced, which is more labor-saving.

[0005] To solve the above technical problems, the technical scheme of the present application is as follows:

[0006] The utility model provides a compact active artificial knee joint with torque adjusting device, which is characterized by comprising a knee joint module, a receiving cavity connecting block, a lower leg connecting piece and a torque adjusting device, wherein the knee joint module comprises a knee joint shell, a knee joint shaft and a knee joint stator sleeve end cover, the torque adjusting device comprises a spiral spring and a bent spring groove, the knee joint shell is in a cylindrical structure and internally provided with a motor, the knee joint shaft is arranged at the center of the knee joint shell, the knee joint stator sleeve end cover is arranged at both ends of the knee joint shell and fixedly connected with the knee joint shaft, the stator of the motor is connected with the knee joint shaft, and the rotor of the motor is connected with the knee joint shell, the receiving cavity connecting block is connected with the knee joint shaft through connecting lugs, the bent spring groove is connected to the knee joint stator sleeve end cover at a position close to the knee joint shaft, and the spiral spring is arranged on the knee joint stator sleeve end cover, with the outer end fixedly connected to the connecting lugs and the inner end fixedly connected to the bent spring groove, and one end of the lower leg connecting piece is fixedly connected to the knee joint shell.

[0007] Further, a plurality of positioning baffles are arranged on the knee joint stator sleeve end cover, which can limit and provide deformation space when the spiral spring is bent under stress.

[0008] Further, the torque adjusting device further comprises a spring box cover plate, which is arranged on the knee joint stator sleeve end cover.

[0009] Further, the spring box cover plate is in a hidden structure.

[0010] Further, the spiral spring is coiled on the knee joint stator sleeve end cover, and the cross section is circular.

[0011] Further, the two ends of the spiral spring are connected to the connecting lugs and the bent spring groove respectively through the transition fit of shaft holes.

[0012] Further, a connecting flat key is arranged between the receiving cavity connecting block and the connecting lugs.

[0013] Further, the knee joint shell and the lower leg connecting piece are hard connected.

[0014] Compared with the prior art, the utility model has the following beneficial effects:

[0015] 1. The torque adjusting device in the utility model can effectively reduce the torque peak value of the knee joint rotating motor, improve the knee joint rotating torque valley value, realize torque assistance and adjustment, select a motor with smaller power and maximum torque, reduce the weight of the knee joint mechanism, save energy consumption, reduce the driving torque of the artificial limb wearer, save labor, and be easy to wear.

[0016] 2, the torque adjusting device is the volute spring, the peak torque difference of the motor in the wearer walking experiment can be determined, the peak torque occurrence point and amplitude are determined, the stiffness, outer diameter and wire diameter of the spring are designed, so as to adapt to different individuals.

[0017] 3, the positioning baffle plays a limiting role when the spring is bent and stressed, maintains stability and limits the spring contour, and provides deformation space.

[0018] 4, the spring box cover plate has the functions of installing the spring and providing working space, can limit the freedom of the spring, and can be designed as a hidden structure, has the effects of shielding and beauty, and realizes compactness. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is the whole structure schematic diagram of the embodiment of the application;

[0020] Figure 2 It is the torque adjusting device structure schematic diagram of the embodiment of the application;

[0021] Figure 3 It is the sectional view of the embodiment of the application;

[0022] Figure 4 It is the volute spring structure schematic diagram of the embodiment of the application;

[0023] Figure 5 It is the working principle diagram of the embodiment of the application;

[0024] Figure 6 It is the driving torque comparison diagram of the prosthetic knee joint with or without torque adjusting device;

[0025] Wherein: 1-receiving cavity connecting block, 2-calf connecting piece, 3-knee joint shell, 4-knee joint axis, 5-knee joint stator sleeve end cover, 6-volute spring, 7-bent spring groove, 8-connection lug, 9-positioning baffle, 10-spring box cover plate, 11-connection flat key, 12-calf rod. DETAILED DESCRIPTION

[0026] In order to deepen the understanding of the application, the application will be further described below in combination with the drawings, and the embodiment is only used to explain the application and does not constitute a limitation on the protection scope of the application.

[0027] Figures 1-4The embodiment of the compact active prosthesis knee joint with torque adjusting device is shown, which comprises a knee joint module, a receiving cavity connecting block 1, a lower leg connecting piece 2, a torque adjusting device, the knee joint module comprises a knee joint shell 3, a knee joint shaft center 4, a knee joint stator sleeve end cover 5, and the torque adjusting device comprises a spiral spring 6 and a bent spring groove 7. The knee joint shell 3 is in a cylindrical structure, and a motor is arranged inside. The knee joint shaft center 4 is arranged at the center of the knee joint shell 3. The knee joint stator sleeve end cover 5 is arranged at both ends of the knee joint shell 3 and is fixedly connected with the knee joint shaft center 4. The stator of the motor is connected with the knee joint shaft center 4, and the rotor of the motor is connected with the knee joint shell 3. The receiving cavity connecting block 1 is connected with the knee joint shaft center 4 through a connecting lug 8. A connecting flat key 11 is arranged between the receiving cavity connecting block 1 and the connecting lug 8. The bent spring groove 7 is connected to the position of the knee joint stator sleeve end cover 5 close to the knee joint shaft center 4. The spiral spring 6 is arranged on the knee joint stator sleeve end cover 5, and the outer end thereof is fixedly connected to the connecting lug 8, and the inner end thereof is fixedly connected to the bent spring groove 7. One end of the lower leg connecting piece 2 is fixedly connected to the knee joint shell 3, and the other end thereof is connected to a lower leg rod 12.

[0028] Preferably, according to the shape of the spiral spring 6 and the deformation characteristics in the movement process, a plurality of positioning baffles 9 are arranged on the knee joint stator sleeve end cover 5. The spiral spring 6 is wound on the knee joint stator sleeve end cover 5 along the positioning baffles 9. The positioning baffles 9 play the roles of limiting, maintaining stability, limiting the outer contour and providing deformation space when the spiral spring 6 is bent under stress.

[0029] The torque adjusting device further comprises a spring box cover plate 10, which is arranged on the knee joint stator sleeve end cover 5. A space is formed between the spring box cover plate 10 and the knee joint stator sleeve end cover 5, which accommodates the stretching and compression deformation of the spiral spring 6, can limit the freedom degree of the spiral spring 6 in other directions, prevent the spiral spring 6 from longitudinally moving out to injure the wearer or others, and can be designed as a hidden structure to play the roles of shielding and aesthetics, and realize compactness.

[0030] The spiral spring 6 should be in a spiral shape, and the cross section thereof is circular. The two ends of the spiral spring 6 are connected to the connecting lug 8 and the bent spring groove 7 respectively through the transition fit of the shaft holes. The bent spring groove 7 can cooperate with the spring box cover plate 10 to limit the translation and rotation freedom degree of the end of the spiral spring 6, and can ensure the effective fixation of the end of the spiral spring 6.

[0031] The knee joint shell 3 and the lower leg connecting piece 2 are hard connected.

[0032] The working principle of the above embodiment is as follows:

[0033] According to the research, the human lower limbs can be divided into swing phase and support phase according to whether the foot is in contact with the ground in a gait cycle. When the prosthesis wearer walks, the leg swings forward, i.e. the swing phase starts, and the lower leg will move forward at this time. At this time, the knee joint shell 3 rotates a negative angle relative to the balance position, and the motor needs to provide a positive torque to drive the knee joint shell 3 and the lower leg rod 12 to rotate clockwise, so as to gradually change the scroll spring 6 into a compressed state, and the scroll spring 6 can provide an additional torque to help the motor do positive work to swing the leg.

[0034] As shown in Figure 5 , first is the swing leg assistance principle. When the knee is bent, the scroll spring 6 is in a compressed state and provides assistance torque for extension. With the same principle, the spring torque can balance part of the body weight torque to buffer the squatting process. When standing up, the scroll spring 6 can provide assistance torque.

[0035] When the lower leg is about to land, i.e. the swing phase is about to end, the lower leg and foot will land. In order to avoid large vibration and impact, the leg needs to be retracted. At this time, the knee joint shell 3 rotates a positive angle relative to the balance position, and the motor needs to provide a negative torque to drive the knee joint shell 3 and the lower leg rod 12 to rotate counterclockwise, so as to gradually change the scroll spring 6 into a stretched state at this time. The scroll spring 6 can provide an additional torque to help the motor do negative work to brake to retract the leg, so a motor with smaller power and maximum torque can be selected to save energy.

[0036] The determination of the balance position of the spring needs to be optimized according to the gait and walking speed of the user. If it is an elderly person or a person with insufficient muscle strength, the balance position point needs to be designed to be closer to the limit position of the swing phase, or even to the limit position. For high-speed walking and low-speed walking, the torque peak value is also different, and the balance position of the spring needs to be adjusted according to the user's needs.

[0037] As shown in Figure 6 , the driving torque comparison diagram when the torque adjusting device is installed in the prosthetic knee joint and when the torque adjusting device is not installed in the prosthetic knee joint. From the curve comparison in the figure, it can be clearly seen that the torque adjusting device can effectively reduce the torque peak value of the knee joint rotating motor, and at the same time can also increase the knee joint rotating torque valley value, realizing torque assistance and adjustment. The selection of the scroll spring 6 is determined according to the actual measurement of the positive and negative peak torque difference of the motor in the wearer's walking experiment. By determining the peak torque occurrence point and amplitude, the stiffness, outer diameter and wire diameter of the scroll spring 6 are designed.

[0038] The above specific embodiments are only for illustrating the technical concept and structural features of the present application, and the purpose is to enable relevant persons skilled in the art to implement it, but the above content does not limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall fall within the protection scope of the present application.

Claims

1. A compact active prosthesis knee joint with a torque adjustment device, characterized in that: The knee joint module, the receiving cavity connecting block (1), the lower leg connecting piece (2), and the torque adjusting device are provided, the knee joint module comprises a knee joint shell (3), a knee joint shaft center (4), and a knee joint stator sleeve end cover (5), the torque adjusting device comprises a spiral spring (6) and a bent spring groove (7), the knee joint shell (3) is in a cylindrical structure, and a motor is arranged in the inside, the knee joint shaft center (4) is arranged at the center of the knee joint shell (3), the knee joint stator sleeve end cover (5) is arranged at both ends of the knee joint shell (3) and is fixedly connected with the knee joint shaft center (4), a stator of the motor is connected with the knee joint shaft center (4), and a rotor of the motor is connected with the knee joint shell (3), the receiving cavity connecting block (1) is connected with the knee joint shaft center (4) through a connecting lug (8), the bent spring groove (7) is connected to a position of the knee joint stator sleeve end cover (5) close to the knee joint shaft center (4), the spiral spring (6) is arranged on the knee joint stator sleeve end cover (5), an outer end of the spiral spring (6) is fixedly connected with the connecting lug (8), and an inner end of the spiral spring (6) is fixedly connected with the bent spring groove (7), one end of the lower leg connecting piece (2) is fixedly connected with the knee joint shell (3). The torque adjusting device further comprises a spring box cover plate (10), and the spring box cover plate (10) is arranged on the knee joint stator sleeve end cover (5). The spring box cover plate (10) is in a hidden structure.

2. A compact active prosthesis knee joint with a torque adjustment device according to claim 1, characterized in that The knee joint stator sleeve end cover (5) is provided with a plurality of positioning baffles (9), and the positioning baffles (9) provide a deformation space when the spiral spring (6) is bent and stressed.

3. The compact active prosthesis knee joint with torque adjustment device according to claim 1, characterized in that: The spiral spring (6) is coiled on the knee joint stator sleeve end cover (5), and a cross section of the spiral spring (6) is circular.

4. The compact active prosthesis knee joint with torque adjustment device according to claim 1, characterized in that: The two ends of the spiral spring (6) are respectively connected with the connecting lug (8) and the bent spring groove (7) through transition matching of shaft holes.

5. The compact active prosthesis knee joint with torque adjustment device according to claim 1, characterized in that: A connecting flat key (11) is arranged between the receiving cavity connecting block (1) and the connecting lug (8).

6. The compact active prosthesis knee joint with torque adjustment device according to claim 1, characterized in that: The knee joint shell (3) and the lower leg connecting piece (2) are hard connected.

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