CN115670759A - Compact type active artificial limb knee joint with moment adjusting device - Google Patents

Abstract

The invention relates to a compact active artificial limb knee joint with a torque adjusting device, which comprises a knee joint module, a receiving cavity connecting block, a shank connecting piece and a torque adjusting device, wherein the torque adjusting device comprises a volute spring, a bent spring groove and the like, the knee joint module comprises a knee joint shell, a knee joint axle center, a knee joint stator sleeve end cover and the like, one end of the spring is fixed at a position connected with a lug of an upper receiving cavity through an opening on the motor stator sleeve end cover, and the other end of the spring is fixed in the bent spring groove at the position of the motor stator sleeve end cover and the knee joint axle center. The moment adjusting device can realize moment assistance and adjustment according to the angle and direction of the limb rotation; meanwhile, the driving peak torque of the motor can be reduced, and the artificial limb is easy to wear, so that the size and the maximum torque of the driving motor are smaller, and the energy consumption and the space are saved.

Description

A compact active prosthetic knee joint with torque adjustment device

technical field

The invention relates to the technical field of knee joint prosthesis, in particular to a compact active prosthetic knee joint with a moment adjustment device.

Background technique

In recent years, biped walking robots have become a hot spot in the field of robotics. Walking robots not only have broad application scenarios in medical treatment, helping the elderly and the disabled, but also have good environmental adaptability and strong movement coordination ability. serve mankind.

Knee joints can be divided into active knee prostheses, passive knee prostheses, and active and passive knee prostheses according to whether humans can provide active moments. Among them, active knee prostheses with many applications require a power source (motor) to provide the main or full torque for the knee joint flexion and extension. Therefore, such active knee prostheses are often designed to be large in size and quality because the motor needs to provide a large torque, and the counterfeiting is high, so it is not easy to be mass-produced and flow into the market, so it is favored by consumers. Therefore, further research on the knee joint needs to use mechanism design or control methods to minimize the peak torque of the motor.

Contents of the invention

The purpose of the present invention is to address the defects of the prior art, and provide a compact active prosthetic knee joint with a torque adjustment device to adjust the torque driven by the joint, so that the peak value is reduced and the valley value is increased, so that power and maximum torque can be selected Smaller motors can reduce the weight of the joint mechanism, save energy, or reduce the driving torque of the prosthetic wearer, saving more effort.

In order to solve the problems of the technologies described above, the present invention provides technical solutions as follows:

A compact active prosthetic knee joint with a torque adjustment device, characterized in that it includes a knee joint module, a socket connection block, a lower leg connection piece, and a torque adjustment device, and the knee joint module includes a knee joint shell, a knee joint Shaft, knee joint stator sleeve end cover, the torque adjustment device includes a scroll spring and a bent spring groove, the knee joint shell is a cylindrical structure, and a motor is arranged inside, and the knee joint axis is set At the center of the knee joint shell, the knee joint stator sleeve end caps are arranged at both ends of the knee joint shell and fixedly connected with the knee joint axis, the stator of the motor is connected with the knee joint axis, and the rotor of the motor is connected with the knee joint axis. The joint housing, the connecting block of the receiving cavity is connected to the axis of the knee joint through the connecting lug, and the bent spring groove is connected to the position of the end cover of the stator sleeve of the knee joint close to the axis of the knee joint. The scroll spring is arranged on the end cover of the stator sleeve of the knee joint, its outer end is fixedly connected to the connecting lug, and its inner end is fixedly connected to the bent spring groove. One end of the lower leg connector is fixedly connected to the knee joint on the shell.

Further, the end cover of the stator sleeve of the knee joint is provided with several positioning baffles, and the positioning baffles play a role of limiting and providing deformation space when the scroll spring is bent and stressed.

Further, the torque adjusting device further includes a spring box cover, and the spring box cover is arranged on the end cover of the knee joint stator sleeve.

Further, the spring box cover is a hidden structure.

Further, the scroll spring is coiled on the end cover of the knee joint stator sleeve, and its cross section is circular.

Further, the two ends of the scroll spring are respectively connected to the connecting lug and the bent spring groove through the transition fit of the shaft hole.

Further, a connection flat key is provided between the socket connection block and the connection lug.

Further, there is a rigid connection between the knee joint shell and the lower leg connecting piece.

Compared with prior art, the beneficial effect of the present invention is:

1. The torque adjusting device in the present invention can effectively reduce the peak torque of the knee joint rotating motor, and can also increase the valley value of the knee joint rotating torque to realize torque assistance and adjustment, so that a motor with smaller power and maximum torque can be selected to reduce The self-weight of the knee joint mechanism saves energy consumption, reduces the driving torque of the prosthetic wearer, saves effort, and is easy to wear.

2. The scroll spring is used as the torque adjustment device, which can be determined according to the positive and negative peak torque difference of the motor in the wearer's walking test. By determining the peak torque occurrence point and amplitude, the stiffness, outer diameter and wire diameter of the spring are designed to adapt to the different individuals.

3. The positioning baffle acts as a limiter when the spring is bent and stressed, maintains stability and limits the outline of the spring, and provides space for deformation.

4. The cover plate of the spring box has the function of installing the spring and providing a working space, which can limit the degree of freedom of the spring, and can be designed as a hidden structure, which has the effect of shielding and aesthetics, and realizes compactness.

Description of drawings

1 is a schematic diagram of the overall structure of an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a torque adjusting device according to an embodiment of the present invention;

Fig. 3 is a sectional view of an embodiment of the present invention;

Fig. 4 is a schematic structural view of a scroll spring according to an embodiment of the present invention;

Fig. 5 is a working principle diagram of an embodiment of the present invention;

Fig. 6 is a comparison diagram of driving torque when the prosthetic knee joint has or does not have a torque adjusting device;

Among them: 1-receptacle connection block, 2-calf connection piece, 3-knee joint shell, 4-knee joint axis, 5-knee joint stator sleeve end cover, 6-volute spring, 7-bending shape Spring groove, 8-connecting lug, 9-positioning baffle, 10-spring box cover plate, 11-connecting flat key, 12-calf rod.

Detailed ways

In order to deepen the understanding of the present invention, the present invention will be further described below in conjunction with the accompanying drawings. This embodiment is only used to explain the present invention, and does not constitute a limitation to the protection scope of the present invention.

Figures 1-4 show a specific embodiment of a compact active prosthetic knee joint with a torque adjustment device, including a knee joint module, a socket connection block 1, a calf connector 2, and a torque adjustment device. The knee joint module includes The knee joint shell 3, the knee joint axis 4, the knee joint stator sleeve end cover 5, and the torque adjustment device include a scroll spring 6 and a bent spring groove 7. The knee joint housing 3 is a cylindrical structure with a motor inside, the knee joint axis 4 is set at the center of the knee joint housing 3, and the knee joint stator sleeve end caps 5 are arranged at both ends of the knee joint housing 3 and connected to the knee joint. The joint axis 4 is fixedly connected, the stator of the motor is connected to the knee joint axis 4, the rotor of the motor is connected to the knee joint shell 3, the socket connection block 1 is connected to the knee joint axis 4 through the connecting lug 8, the socket connection block 1 and Connecting flat keys 11 are arranged between the connecting lugs 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 axis 4, the scroll spring 6 is arranged on the knee joint stator sleeve end cover 5, and its outer end is fixedly connected to the connecting hanger. On the ear 8 , the inner end is fixedly connected to the bent spring groove 7 , one end of the lower leg connector 2 is fixedly connected to the knee joint shell 3 , and the other end is connected to the lower leg rod 12 .

Preferably, according to the shape of the scroll spring 6 and the deformation characteristics during the movement, several positioning baffles 9 are arranged on the end cover 5 of the stator sleeve of the knee joint, and the scroll spring 6 is coiled on the knee joint stator sleeve along the positioning baffle 9 On the cylinder end cover 5, the positioning baffle 9 plays the role of limiting the position, maintaining stability, defining the outer contour and providing deformation space when the scroll spring 6 is bent and stressed.

The torque adjusting device also includes a spring box cover plate 10 , and the spring box cover plate 10 is covered on the end cover 5 of the stator sleeve of the knee joint. A space is formed between the spring box cover plate 10 and the knee joint stator sleeve end cover 5 to accommodate the stretching and compression deformation of the scroll spring 6, which can limit the freedom of the scroll spring 6 in other directions and prevent the scroll spring 6 from occurring. The vertical displacement can pop up to accidentally injure the wearer or others, and it can be designed as a hidden structure, which has the effect of shielding and aesthetics, and realizes compactness.

The scroll spring 6 should be in a helical scroll shape with a circular cross section. The two ends of the scroll spring 6 are respectively connected to the connecting lug 8 and the bent spring groove 7 through the transition fit of the shaft hole. The bent spring groove 7 can cooperate with the spring box cover plate 10 to limit the freedom of translation and rotation of the end of the scroll spring 6, and can ensure the effective fixing of the end of the scroll spring 6.

There is a hard connection between the knee joint shell 3 and the lower leg connecting piece 2 .

The working principle of the above-mentioned embodiment is as follows:

According to research, the human lower limbs can be divided into a swing period and a support period in a gait cycle according to whether the foot touches the ground or not. When the prosthesis wearer walks and swings his leg forward, that is, at the beginning of the swing period, the calf is about to move forward. At this time, the knee joint shell 3 rotates at a negative angle relative to the equilibrium position, and the motor needs to provide a positive torque drive. The knee joint shell 3 and the calf rod 12 rotate clockwise, thereby driving the scroll spring 6 to gradually become compressed, and the scroll spring 6 can provide extra torque to help the motor do positive work to swing the legs;

As shown in Fig. 5, firstly, it is the principle of power-assisted leg swinging. When the knee is bent, the scroll spring 6 is in a compressed state to provide the power-assisted torque for stretching. In the same principle, the spring moment can balance part of the body weight moment when squatting, and buffer the squatting process. Scroll spring 6 can provide assist torque when squatting.

When the calf is about to touch the ground, that is, when the swing period is about to end, the calf and the foot are about to land. In order to avoid greater vibration and collision, the legs need to be retracted. At this time, the knee joint shell 3 rotates a positive angle relative to the equilibrium position , the motor needs to provide negative torque to drive the knee joint shell 3 and the calf rod 12 to rotate counterclockwise, thus driving the scroll spring 6 to gradually become stretched at this time, and the scroll spring 6 can provide additional torque to help the motor do negative work. The legs are retracted by braking, so a motor with lower power and maximum torque can be selected to save energy consumption.

The determination of the balance position of the spring needs to be optimized according to the user's gait and pace. For the elderly or those with insufficient muscle strength, the balance position point needs to be designed closer to the limit position of the swing period, or even designed as the limit position. For high-speed walking and low-speed walking, the peak torque is also different, and the balance position of the spring needs to be adjusted according to the needs of the user.

As shown in Fig. 6, it is a comparison diagram of the driving torque when the prosthetic knee joint is equipped with a torque adjustment device and without a torque adjustment device. From the comparison of the curves in the figure, it can be clearly seen that the torque adjustment device can effectively reduce the peak torque of the knee joint rotation motor, and at the same time increase the valley value of the knee joint rotation torque to achieve torque assistance and adjustment. The selection of the scroll spring 6 is determined according to the positive and negative peak torque difference of the middle motor measured by the wearer's walking experiment. By determining the peak torque generation point and amplitude, the stiffness, outer diameter and wire diameter of the scroll spring 6 are designed.

The above-mentioned specific implementation is only to illustrate the technical concept and structural features of the present invention, and the purpose is to allow relevant persons familiar with this technology to implement it accordingly, but the above content does not limit the scope of protection of the present invention. Any equivalent change or modification made in essence shall fall within the protection scope of the present invention.

Claims (8)

1. A compact initiative artificial limb knee joint with moment adjusting device which characterized in that: including knee joint module, accepting chamber connecting block (1), shank connecting piece (2), moment adjusting device, the knee joint module includes knee joint casing (3), knee joint axle center (4), knee joint stator sleeve end cover (5), moment adjusting device includes spiral spring (6), shape spring groove (7) of bending, knee joint casing (3) are cylindrical structure, and inside is provided with the motor, knee joint axle center (4) set up in the center of knee joint casing (3), knee joint stator sleeve end cover (5) set up at knee joint casing (3) both ends and with knee joint axle center (4) fixed connection, knee joint axle center (4) is connected to the stator of motor, knee joint casing (3) is connected to the rotor of motor, accepting chamber connecting block (1) is connected through connecting hangers (8) knee joint axle center (4), shape spring groove (7) of bending connect in on knee joint stator sleeve end cover (5) is close to the position of knee joint axle center (4), spring spiral (6) set up on knee joint stator sleeve end cover (5), its outer end is connected on connecting hangers (8), and inner fixed connection is in shape spring groove (7) of bending, the one end of bending is connected on the shank fixed connection (3).

2. The compact active prosthetic knee joint with moment adjustment device of claim 1, wherein: a plurality of positioning baffles (9) are arranged on the knee joint stator sleeve end cover (5), and the positioning baffles (9) play roles of limiting and providing deformation space when the volute spiral spring (6) is subjected to bending stress.

3. The compact active prosthetic knee joint with moment adjustment device of claim 1, wherein: the moment adjusting device further comprises a spring box cover plate (10), and the spring box cover plate (10) is covered on the knee joint stator sleeve end cover (5).

4. The compact active prosthetic knee joint with moment adjustment according to claim 3, wherein: the spring box cover plate (10) is of a hidden structure.

5. The compact active prosthetic knee joint with moment adjustment device of claim 1, wherein: the volute spiral spring (6) is coiled on the knee joint stator sleeve end cover (5), and the cross section of the volute spiral spring is circular.

6. The compact active prosthetic knee joint with moment adjustment device of claim 1, wherein: two ends of the volute spiral spring (6) are respectively connected to the connecting hanging lug (8) and the bent spring groove (7) through transition fit of the shaft hole.

7. The compact active prosthetic knee joint with moment adjustment device of claim 1, wherein: a connecting flat key (11) is arranged between the receiving cavity connecting block (1) and the connecting suspension loop (8).

8. The compact active prosthetic knee joint with moment adjustment device of claim 1, wherein: the knee joint shell (3) is in hard connection with the shank connecting piece (2).

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