JP6713689B2 - Implantable motion assist device and implantable walking assist device - Google Patents

Description

The present invention relates to an in-body implanting type motion assist device that is embedded in the wearer's body to assist movement of joints, and an in-body implanting type walk assist device that assists movements of hip joints, knee joints, and the like in walking motions.

Known examples of this type of device include a powered artificial joint disclosed in Patent Document 1 and an implantable motion assisting device disclosed in Patent Document 2. In the powered artificial joint disclosed in Patent Document 1, an actuator is incorporated in the artificial joint to apply an assisting force for moving the artificial joint to the artificial joint. In the implantable motion assisting device disclosed in Patent Document 2, each of two rims driven by an electric motor is fixed to each bone connected by a joint, and an assisting force from the electric motor is applied to each bone. I have to. FIG. 23 of Patent Document 2 also proposes a configuration in which motion assisting units are attached to both sides of the joint of the wearer to assist the movement of the joint.

JP, 2006-26197, A JP, 2009-95382, A

The powered artificial joint disclosed in Patent Document 1 is suitable for a person who cannot move his arm or leg due to a disease of the joint. However, it is premised on an artificial joint and is not suitable for a person who has a healthy joint portion but has difficulty in walking or the like due to weakened muscle strength or the like.

In the implantable motion assisting device disclosed in Patent Document 2, the rotational force of the electric motor is transmitted to each bone connected by a joint via a rim. Although the connecting portion between the electric motor and each bone is reinforced by the rim, when the bone is weak, the bone is overloaded.

An object of the present invention is to provide an implantable motion assist device and an implantable walk assist device that can assist a motion such as walking without imposing an excessive load on the wearer's joints, bones, and the like. ..

The implantable motion assist device of the present invention is
A first intramedullary nail inserted into the medullary cavity of the first bone to reinforce the first bone connected to the joint;
A first fixture for securing the first intramedullary nail to the first bone;
A second fastener fixed to a second bone connected to the joint,
An actuator for transmitting an assisting force for assisting the movement of the first bone and the second bone around the fulcrum of the joint to each of the first fixture and the second fixture. Cage,
The actuator uses the turning force for turning the first and second fixtures toward and away from each other about a preset turning center line as the assisting force to the first and second fixings. The feature is that it is transmitted to the ingredients .

The implantable motion assist device of the present invention focuses on intramedullary nail technology used for treatment of fractures, patients suffering from joint diseases, etc., and fixes the intramedullary nail and the intramedullary nail to bone. By using a fixing tool for this, the assist force output from the actuator is transmitted to the bone connected to the joint to be assisted.

Since the intramedullary nail is inserted into the medullary canal passing through the center of the bone, it is not necessary to secure a space for attaching a connecting plate such as a rim along the outer surface of the bone. Therefore, the damage to the parts around the joints of the human body can be reduced. Also, the assist force from the actuator is transmitted from the fixture to the intramedullary nail and bone. Since the intramedullary nail is generally arranged over almost the entire length of the bone, stress is not concentrated on the assist force transmitting portion. Further, since the bone is reinforced by the intramedullary nail, it becomes possible to apply a larger assisting force, and the movement of the joint portion can be made to be a smooth movement close to that of a healthy person.

According to the present invention, it is possible to realize an implantable motion assist device capable of smoothly performing a motion such as walking without imposing an excessive burden on the wearer's joints and bones.

When the implantable motion assist device of the present invention is applied to a hip joint, the first intramedullary nail is inserted into one femur connected to the joint and fixed with the first fixture, and the other is fixed. A second fixing tool is fixed to the pelvis side bone such as the hip bone, and the assist force from the actuator is transmitted to each bone through the first and second fixing tools. When the present invention is applied to the shoulder joint, the first intramedullary nail is inserted into one humerus connected to the joint and fixed with the first fixing tool, and the other scapula has the second The fixture is fixed, and the assist force from the actuator is transmitted to each bone through the first and second fixtures.

When the implantable motion assist device of the present invention is applied to the knee joint between the femur and the tibia, the first intramedullary nail is inserted into the femur and fixed with the first fixture, while A second intramedullary nail is inserted into the tibia and fixed by the second fixing tool, and the assist force from the actuator is transmitted to each bone through the first and second fixing tools.

In the present invention, as the actuator, a rotary actuator including an electric motor and a speed reducer can be used. The rotary actuator uses, as an assisting force, a turning force that turns the first and second fixtures in a relatively approaching direction and a leaving direction around a preset turning center line, as a assisting force. Configured to communicate with.

The rotary actuator is the largest component among the components of the implantable motion assist device. Due to the structure of the human body, in many cases, there is not enough space for embedding the rotary actuator in the lateral part of the joint. In the conventional embedded motion assist device, a rotary actuator composed of an electric motor or the like is embedded coaxially with the joint axis of the joint. Therefore, it is difficult to secure a space in which a rotary actuator can be embedded in a lateral part such as a knee joint or an elbow joint.

In the present invention, in order to allow the embedded position of the rotary actuator to be located at a position deviated from the lateral position of the joint part, the turning center lines of the first and second fixtures are set to the output rotary shaft of the rotary actuator. The center axis of is offset by a predetermined amount. By properly setting the offset amount according to the human body structure around the joint to be assisted, the rotary actuator can be easily embedded in the human body. Can be matched to the fulcrum of.

Since the hip joint or the like is a so-called multi-degree-of-freedom ball joint, it is desirable to configure an assist force transmission path so as to be able to flexibly cope with such movement of the joint portion.

In the present invention, the first and second swivel arms that swivel in the opposite direction in synchronization with each other by the rotary actuator in the opposite direction are arranged, and one of the first and second swivel arms is set to the first swivel arm. Is hinged to the second fixing tool or the second fixing tool. Accordingly, unlike the conventional case in which the assist force transmitting member is rigidly connected to each bone, it is possible to follow the flexible movement of the joint portion, which is preferable.

In the present invention, the control unit that controls the drive of the rotary actuator can be an implantable control unit that can be embedded in the wearer's body. Similarly, a power source for supplying drive power to the rotary actuator and the control unit can be an implantable battery power source that can be embedded in the wearer's body.

In particular, the implantable movement assist device of the present invention can be applied as an implantable walking assist device to an elderly person who has difficulty walking, a disabled person, or a person who cannot or cannot walk due to a cranial nerve disease or the like.

The implantable walking assist device in this case includes, for example, a hip joint assist device that assists movement of the wearer around the hip joint and a knee joint assist device that assists movement of the wearer around the knee joint. It can be configured. The hip joint assist device is configured to include two intramedullary nails, two fixtures, and an actuator. Similarly, the knee joint assist device is configured to include two intramedullary nails, two fixtures, and an actuator.

1 is an explanatory diagram showing an embodiment of an implantable walking assist device to which the present invention is applied. It is explanatory drawing which expands and shows the part of the hip joint assist unit and the knee joint assist unit of FIG. It is explanatory drawing which shows an example of a rotary actuator.

Embodiments of the present invention will be described below with reference to the drawings. Although the following embodiments relate to an implantable walking assist device, the present invention relates to an implantable motion assist device for assisting a motion other than walking, for example, a motion such as raising and lowering of an arm or bending and stretching of an elbow. Can be used as

(overall structure)
FIG. 1 is an explanatory diagram showing a schematic configuration of an implantable walking assist device according to the present embodiment. FIG. 2A is an explanatory view showing a hip joint assist unit portion of the implantable walking assist device, and FIG. 2B is an explanatory view showing a knee joint assist unit portion thereof.

The implantable walking assist device 1 (hereinafter referred to as “walking assist device 1”) is embedded in the wearer's body, in this example, the left foot 11 to assist the movement of the left foot 11. The walking assist device 1 includes a hip joint assist unit 2 that assists a movement around a left hip joint 12, and a knee joint assist unit 3 that assists a movement around a wearer's left knee joint 13. .. In addition, a non-contact charging type battery power source 4 which is embedded in the body and is a power source for these power sources is provided.

The implantable battery power source 4 is embedded, for example, above the iliac bone 16 of the pelvis. Power supply cords 41 and 42 extend from the battery power source 4. One power supply cord 41 is connected to the upper hip joint assist unit 2, and the other power supply cord 42 extends through the inside of the left foot to the lower knee joint assist unit 3 and is connected to the unit 3.

(Hip joint assist unit)
The hip joint assist unit 2 will be described with reference to FIGS. 1 and 2A. The hip joint assist unit 2 includes an intramedullary nail 21 (first intramedullary nail) inserted into the intramedullary cavity of the femur 14 (first bone) and a screw screw for fixing the intramedullary nail 21 to the femur 14. 22 (first fixing tool), a screw screw 23 (second fixing tool) fixed to the hip bone 15 (second bone) side of the pelvis, and the fulcrum of the hip joint 12 are set. The rotary actuator 24 transmits a turning force that relatively turns the screw screws 22 and 23 in the opening/closing direction about the turning center line 27a as an assist force.

The intramedullary nail 21 is inserted into the intramedullary cavity of the femur 14 to reinforce the femur 14 connected to the hip joint 12. The intramedullary nail 21 is an elongated rod made of a metal having a circular cross section that extends linearly as a whole, and is inserted from the upper end surface of the upper epiphysis 14a of the femur 14 to a position near the lower epiphysis. It is extended. The upper end portion of the intramedullary nail 21 projects upward from the upper end surface of the femur 14 by a predetermined dimension.

A screw screw 22 for fixing an intramedullary nail is obliquely screwed into the upper bone end 14a of the femur 14 from the upper left outer side to the lower inner side. The screw screw 22 extends through the upper end portion 21a of the intramedullary nail 21 located inside the upper bone end 14a of the femur 14. The intramedullary nail 21 is fixed to the epiphysis 14a portion of the femur 14 by the screw screw 22. The head 22a of the screw screw 22 projects from the femur 14 by a predetermined amount.

On the other hand, the screw screw 23 is screwed and fixed obliquely upward from the left outer side to the inner side of the ilium 16 of the upper pelvis-side hip bone 15 connected to the hip joint 12. The head 23a of the screw screw 23 fixed to the iliac part 16 also projects from the iliac part 16 by a predetermined amount.

The rotary actuator 24 includes an electric motor 24a, a speed reducer 24b that decelerates and outputs the output, and a control unit 24c that controls the drive of the electric motor 24a. By the output rotation of the rotary actuator 24, the pair of upper and lower revolving arms 25 and 26 can relatively revolve around a revolving center line 27a passing through the joint center of the hip joint 12 in the opening and closing directions.

That is, one end of the upper turning arm 25 is fixed to the housing 24A of the rotary actuator 24, and the other end (upper end) is fixed to the head 23a of the screw screw 23. One end of the lower swivel arm 26 is supported by a swivel center shaft 27 fixed to the housing 24A, and is rotatable about a swivel center line 27a which is the central axis line. The other end (lower end) of the swivel arm 26 is connected to the head portion 22a of the screw screw 22 via a hinge coupling portion 29. The output rotation from the rotary actuator 24 is transmitted to the swivel arm 26 supported by the swivel center shaft 27 via a transmission mechanism such as a gear train (not shown), and the swivel arm 26 swivels around the swivel centerline 27a. To do.

The embedded position of the rotary actuator 24 is a position deviated upward from the left lateral position of the hip joint 12. In order to be able to arrange in this position, the turning center axis 27 of the turning arms 25 and 26 is offset downward by a predetermined amount with respect to the center axis line 24d of the output rotation axis of the rotation actuator 24. By properly setting the offset amount Δ1, the rotary actuator 24 can be embedded in the wearer's body without difficulty. Further, in the embedded state, the turning center line 27a of the turning arms 25 and 26 can be aligned with the fulcrum of the hip joint 12.

(Knee joint assist unit)
Next, the knee joint assist unit 3 will be described with reference to FIGS. 1 and 2B. The knee joint assist unit 3 includes the above-mentioned intramedullary nail 21 (first intramedullary nail) inserted into the intramedullary cavity of the femur 14 (first bone) and the lower end portion 21b of the intramedullary nail 21. The lateral nail 32 (first fixing tool) fixed to the femur 14, the intramedullary nail 31 (second intramedullary nail) inserted into the tibia 17 (second bone), and the intramedullary nail 31 The screw screws 33 (second fixing tool) for fixing the upper end side portion 31a to the tibia 17 and the screw screws 32, 33 are relatively rotated in the opening/closing direction about a rotation center line 37a passing through the fulcrum of the knee joint 13. The rotary actuator 34 for transmitting the turning force as an assist force.

The lower end portion 21b of the intramedullary nail 21 is fixed to the femur 14 by a screw screw 32 which is screwed and fixed inward from the left outer side to the upper side portion of the lower bone end 14b of the femur 14. The head portion 32 a of the screw screw 32 projects laterally leftward from the femur 14.

The other intramedullary nail 31 is inserted into the intramedullary cavity of the tibia 17 to reinforce the tibia 17 connected to the knee joint 13. Like the intramedullary nail 21, the intramedullary nail 31 is a slender rod having a circular cross section made of metal and extending linearly as a whole, and is inserted from the upper end surface of the upper epiphysis 17a of the tibia 17 and below the same. It extends to the lateral epiphysis 17b.

The intramedullary nail 31 is fixed to the tibia 17 by a screw screw 33 that is laterally screwed and fixed to the upper bone end 17a of the tibia 17. The head portion 33a of the screw screw 33 projects laterally laterally from the tibia 17. Further, the intramedullary nail 31 is fixed to the tibia 17 by a plurality of lateral stop nails 40a, 40b, 40c,... At its upper end portion 31a and lower end portion 31b. In addition, in FIG. 1, among the lateral stop nails, the lateral stop nails 40b and 40c are fixed to the tibia 17 while penetrating from one side of the tibia 17 to the other side. These lateral pegs can be fixed to the bone with or without penetration, if desired. The same applies to other screw threads.

The rotary actuator 34 includes an electric motor 34a, a speed reducer 34b that decelerates and outputs the output, and a control unit 34c for driving and controlling the electric motor 34a. By the output rotation of the rotary actuator 34, the pair of upper and lower revolving arms 35 and 36 can revolve around the revolving center line 37a passing through the joint center of the knee joint 13 in the directions of opening and closing each other.

That is, the lower end of the upper swing arm 35 is fixed to the housing 34A of the rotary actuator 34, and the other end (upper end) is fixed to the head portion 32a of the screw screw 32. An upper end of the lower swivel arm 36 is supported by a swivel center shaft 37 fixed to the housing 34A, and is rotatable about a swivel center line 37a which is a central axis line thereof. The lower end of the swivel arm 36 is connected to the head portion 33a of the screw screw 33 via a hinge coupling portion 39. The output rotation from the rotary actuator 34 is transmitted to a swivel arm 36 supported by a swivel center shaft 37 via a transmission mechanism such as a gear train (not shown), and the swivel arm 36 swivels around a swivel centerline 37a. To do.

The embedded position of the rotary actuator 34 is a position deviated upward from the left lateral position of the knee joint 13. In order to be embedded in this position, the turning center axis 37 of the turning arms 35 and 36 is offset downward by a predetermined amount with respect to the center axis 34d of the output rotation axis of the rotary actuator 34. By properly setting the offset amount Δ2, the rotary actuator 34 can be embedded in the wearer's body without difficulty. Further, in the embedded state, the turning center line 37a of the turning arms 35 and 36 can be aligned with the fulcrum of the knee joint 13.

(Example of drive control system)
In the walking assist device 1 having this configuration, the control unit 24c of the hip joint assist unit 2 and the control unit 34c of the knee joint assist unit 3 operate on each joint by, for example, tuning control using a phase oscillator model. The drive control of the electric motors 24a and 34a is performed so that an appropriate drive torque is applied to the joint in synchronism with the acting torque. In this case, the encoder detects the joint angle, the torque sensor detects the interaction torque, and the drive torque is calculated based on these detected values. Regarding tuning control using such a phase vibration model, for example, Japanese Patent Laid-Open No. 2012-66375, “Tuning control of robotic suit using phase oscillator” (Proceedings, 13th Construction Robot Symposium, 2012) (Held September 11, 2012).

(Example of rotary actuator)
FIG. 3 is a conceptual diagram showing an example of the rotary actuator. For example, a rotary actuator 50 that can be used as the rotary actuator 34 attached to the knee joint 13 is an outer rotor type electric motor 52 incorporated in a flat cylindrical case 51 (housing), a wave gear reducer 53, and A control board 54 is provided.

The wave gear reducer 53 is a flat wave gear reducer, and includes a stationary side internal gear 55, a drive side internal gear 56, and a cylindrical flexible external gear 57 arranged inside these. The wave generator 58 mounted inside this is provided. The external gear 57 is bent into an elliptical shape by the wave generator 58, and meshes with the internal gears 55 and 56 at the positions of both ends of the major axis thereof.

The wave generator 58 includes a rigid plug having an elliptical outer peripheral surface, and the rigid plug functions as an outer rotor 52a having a drive magnet for the electric motor 52. Inside the wave generator 58, a stator 52b having a drive coil for the electric motor 52 is arranged.

The stationary internal gear 55 is fixed to the cylindrical case 51, and the rotating arm 35 is integrally formed on the cylindrical case 51. The external gear 61 is also formed on the outer peripheral surface of the other drive-side internal gear 56, and the external gear 61 is rotatably supported by the turning center shaft 37 fixed to the cylindrical case 51. It meshes with the transmission gear 62. A swivel arm 36 is formed integrally with the transmission gear 62, and a rotation center line of the transmission gear 62 defines a swivel center line 37 a of the swivel arm 36. The rotation of the internal gear 56 allows the turning arm 36 to turn about the turning center line 37a.

When the electric motor 52 is driven to rotate its outer rotor, the wave generator 58 formed integrally there also rotates. When the wave generator 58 rotates, the meshing positions between the external gear 57 and the internal gears 55 and 56, which are bent in an elliptical shape by the wave generator 58, also move in the circumferential direction. The external gear 57 and the drive-side internal gear 56 have the same number of teeth, and the stationary internal gear 55 has, for example, two more teeth than these. Therefore, when the wave generator 58 makes one rotation, relative rotation of the difference in the number of teeth occurs between the internal gears 55 and 56. Therefore, by the relative rotation of the internal gears 55 and 56, the swivel arms 35 and 36 relatively swivel about the swivel centerline 37a.

(Other embodiments)
In the above example, the implantable motion assist device of the present invention is attached to the joint of the wearer. When the wearer's joint has an obstacle, it is possible to implant an artificial joint and attach the implantable motion assist device of the present invention to the artificial joint.

Further, as the material of each component of the implantable motion assist device of the present invention, various materials such as metal such as titanium, ceramics, fiber reinforced plastic and the like can be used.

Claims (13)

A first intramedullary nail inserted into the medullary cavity of the first bone to reinforce the first bone connected to the joint of the wearer;
A first fixture for securing the first intramedullary nail to the first bone;
A second fixture fixed to a second bone connected to the joint;
Actuators for transmitting assist forces for assisting the movement of the first bone and the second bone around the fulcrum of the joint to the first fixture and the second fixture, respectively. When,
A has,
The actuator uses the turning force for turning the first and second fixtures toward and away from each other about a preset turning center line as the assisting force. An implantable motion assist device that is transmitted to a device. In claim 1,
A second intramedullary nail inserted into the intramedullary cavity of the second bone;
The implantable motion assist device according to claim 1, wherein the second fixture is a fixture for fixing the second intramedullary nail to the second bone. In claim 1,
The implantable motion assist device according to claim 1, wherein the first intramedullary nail is inserted into a femur connected to a hip joint, and the second fixture is fixed to a hip bone connected to a hip joint. In claim 2,
The first intramedullary nail is inserted into the femur connected to the knee joint, and the second intramedullary nail is inserted into the tibia connected to the knee joint. .. In claim 1 or 2,
The actuator implantable operation assisting device is a rotary actuator having an electric motor and reduction gear. In claim 5,
The implantable operation assist device, wherein the turning centerlines of the first and second fixtures are offset by a predetermined amount with respect to the center axis of the output rotary shaft of the rotary actuator. In claim 6,
The rotary actuator has first and second swivel arms that can swivel in the opposite directions about the swivel center line in synchronization with each other,
One of the first and second swivel arms is hinged to the first fixture or the second fixture,
The implantable motion assist device, wherein the turning force is transmitted to each of the first and second fixtures via the first and second turning arms. In claim 1 or 2,
An implantable control unit for controlling the drive of the actuator,
An implantable operation assist device having an implantable battery power source for supplying drive power to the actuator and the control unit. It has a hip joint assist unit that assists movement of the wearer centering on the hip joint, and a knee joint assist unit that assists movement of the wearer centering on the knee joint.
The hip joint assist unit is the implantable motion assist device according to claim 3,
The in-body implanting type walking assist device, wherein the knee joint assist unit is the in-body implanting type motion assist device according to claim 4. In claim 9,
An implantable walking assist device in which each of the actuators in the hip joint assist unit and the knee joint assist unit is a rotary actuator including an electric motor and a speed reducer. In claim 10,
The implantable walking assist device according to claim 1, wherein the turning centerlines of the first and second fixtures are offset by a predetermined amount with respect to a center axis of an output rotation shaft of the rotary actuator. In claim 11,
The rotary actuator has first and second swivel arms that can swivel in the opposite directions about the swivel center line in synchronization with each other,
One of the first and second swivel arms is hinged to the first fixture or the second fixture,
The implantable walking assist device, wherein the turning force is transmitted to each of the first and second fixing tools via the first and second turning arms. In claim 9,
An implantable control unit for controlling the drive of the actuator,
An implantable walking assist device having an implantable battery that supplies drive power to the actuator and the control unit.

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