WO2018008705A1

WO2018008705A1 - Body-implanted motion assist device

Info

Publication number: WO2018008705A1
Application number: PCT/JP2017/024728
Authority: WO
Inventors: 直人齋藤; 橋本　稔; 道彦小関; 淳塚原
Original assignee: 国立大学法人信州大学
Priority date: 2016-07-05
Filing date: 2017-07-05
Publication date: 2018-01-11
Also published as: JP6975464B2; JPWO2018008705A1

Abstract

A body-implanted motion assist device (1) that sandwiches a hip joint (12) between a thigh bone (14) and a pelvis-side bone (15) at which movements, such as bending/stretching motions, that are centered on the hip joint (12) originate. A first string (28) and a second string (29) are strung over the front side and the rear side of the device. An assist-force-generating rotary actuator (24) is fixed to the pelvis-side bone (15). The rotary actuator (24) pulls the first and second strings (28, 29), and, as a result, pulling force that assists bending/stretching motions, etc. that are centered on the hip joint (12) is transmitted to a hip joint section. The present invention achieves a body-implanted motion assist device that can transmit necessary assist force to a joint of a human body without restricting the natural movement of the joint.

Description

Implantable motion assist device

The present invention relates to an implantable motion assist device that is used by being implanted in a wearer's body in order to assist movement around a joint such as a hip joint and a knee joint.

This type of implantable motion assist device is disclosed in

Patent Documents

1 and 2. In the powered artificial joint disclosed in Patent Document 1, an actuator is incorporated in the artificial joint, and assist force for moving the artificial joint is applied to the artificial joint. Artificial joints are not suitable for people whose joints are healthy but who have difficulty in walking or other movements due to reduced muscle strength.

In the implantable motion assist device disclosed in Patent Document 2, each of the two rims driven by the electric motor is fixed to each bone connected to the joint, and the assisting force from the electric motor is applied to each bone. I am doing so. It can be used for people who have healthy joints but have difficulty in walking and other movements.

In the motion assist devices disclosed in

Patent Documents

1 and 2, the rotational force of the electric motor is transmitted to each bone via a rigid member. A rigid member for transmitting the assist force turns in the front-rear direction of the human body around the mechanical joint axis provided in the motion assist device. The assist force generated by the motion assist device acts on the joints of the human body around a fixed position.

The movement of each joint part of the human body is complicated. For example, in the knee joint, the joint axis of the knee joint moves by twisting back and forth and up and down as the knee bends and stretches. In ball joint type joints such as hip joints and shoulder joints, the joint center does not move substantially, but in addition to forward and backward bending and extension movements, adduction / extraction movement, internal rotation / external rotation movement, and Their combined movement occurs.

In the conventional general motion assist device, an assist force transmission system is constituted by a rigid member, and the center position of the assist force for assisting the bending and stretching movement is fixed. In such an operation assist device, it is impossible to follow a movement centering around a complicated human body joint part, and an original natural movement cannot be reproduced. When the motion assist device is mounted, the movement of the joint portion assisted by the motion assist device is restricted by the motion of the motion assist device. As a result, an unnecessary force acts on the joint part of the human body, and the joint may not move, or the wearer may feel restrained or uncomfortable.

On the other hand, Patent Documents 3 and 4 propose an exterior type motion assist device. In the motion assist devices described in Patent Documents 3 and 4, consideration is given to the movement of the joint axis in the front-rear direction and the up-down direction associated with the bending and stretching movements of the knee joint. A mechanism is provided for moving the rotation axis of the assisting force of the bending / extending movement back and forth and in the vertical direction in accordance with the bending / extending movement of the human body.

JP 2006-26197 A JP 2009-95382 A JP 2007-275482 A JP 2013-70783 A

The implantable motion assist device targeted by the present invention assists motions such as walking motion without using an artificial joint as described in Patent Document 2. In such an implantable motion assist device, conventionally, movement of the joint axis of the human body accompanying bending and stretching movements is not considered. Further, there has not been proposed an implantable motion assist device suitable for use in a hip joint or the like in which an internal / external rotation motion, an internal / external rotation motion, or a combined motion thereof occurs in addition to a bending / extension motion.

It is conceivable to apply the exterior type motion assist device described in Patent Documents 3 and 4 to the implantable motion assist device used for the knee joint. That is, it is conceivable to employ a mechanism that moves the rotation axis of the assist force on the apparatus side in the front-rear and vertical directions. However, the mechanism for moving the rotation axis of the assist force in the exterior type motion assist device is configured to move the rotation axis in the front-rear direction using a complex link mechanism or a plurality of actuators. Such a mechanism has a complicated structure and is not easily miniaturized, and is not suitable for implantation in the body.

Also, the conventional mechanism reciprocates the rotating shaft of the assist force along a uniquely defined trajectory. However, the movement of the joint axis of the joint part of the human body accompanying bending and stretching movements during walking movements is complicated. Even if the rotational center of the assist force on the side of the motion assist device is moved along a uniquely defined trajectory, the joint may not move. In addition, there are cases where an assist operation without a sense of restraint or discomfort for the wearer cannot be realized.

Furthermore, in the case of the exterior type motion assist device, for example, play can be made in the state of mounting the device on the human body. By this play, it is relatively easy to absorb the difference between the movement of the joints of the human body and the movement of the apparatus. In the implantable motion assist device, device components are arranged in a limited space inside the body. Each component is fixed without play to each of a pair of bones connected to the joint. When a deviation occurs between the movement on the apparatus side and the movement on the human body side, it acts as a large restraining force on the joint of the wearer.

An object of the present invention is to provide an implantable motion assist device that can transmit a necessary assist force to a joint without restricting natural movement of each joint of a human body.

The implantable motion assist device according to the present invention is used by being implanted in the body in order to assist the movement of the joint of the wearer. In the implantable motion assist device according to the present invention, a pair of bones that perform relative motion around a joint are referred to as first and second bones, and the first bone or the tendon connected to the first bone is the first. When the second bone or the tendon connected to the second bone is called the second portion, the tensile force for assisting the movement in the first direction in the relative motion is the first, A flexible linear member used for transmission between the second parts and an actuator for applying a tensile force to the linear member are provided.

In the present invention, the term “linear member” means a wide and long member, and includes various types of elongated members called a string, a wire, a rope, a tape, a belt, and the like. Various cross-sectional shapes such as a circular cross-section, a flat elliptical cross-section, and a hollow cross-section are also included. Furthermore, it includes a linear member made of one linear material, and a linear member in the form of a ground yarn in which a plurality of linear materials (fibrous materials) are bundled. A linear member is a member that has sufficient tensile strength to transmit the required assist force and has sufficient flexibility or flexibility to follow the movement of the joint of the human body. That's fine. As a material of the linear member, for example, carbon fiber, titanium, a polymer, or the like can be used.

In the present invention, for example, the linear member is bridged between the first and second portions, and the actuator is engaged with the linear member so that the length of the bridging portion of the linear member can be increased or decreased. Let

Or, the actuator is attached to one side of the first and second parts, one end of the linear member is attached to the other side, and the other end side of the linear member can be pulled. An actuator is engaged with the other end of the member.

The actuator is driven in a direction in which the length of the bridging portion of the linear member is shortened in a joint mainly performing extension / bending motion, for example, a knee joint. Alternatively, the linear member is pulled directly by the actuator. Thereby, the assist force of the extension exercise | movement which both bones extend relatively centering on a knee joint can be applied as a tensile force via a linear member. When the length of the bridging portion of the linear member is returned to the original length or when the linear member is loosened, the assist force (tensile force) is released, and a bending motion in which both bones approach is possible. .

Similarly, in the case of a ball joint type joint, for example, a hip joint, an assisting force for bending and stretching movement around the hip joint can be applied in the form of a tensile force. Moreover, the assist force of the internal rotation motion or the external rotation motion and the assist force of the internal rotation motion or the external rotation motion can be applied from the actuator in the form of a tensile force via the linear member.

The assist force transmission path is formed by a flexible linear member, and the rotation axis or center of the assist force is not defined on the apparatus side. The assist force always acts on the joint around the joint axis or joint center of the joint of the human body. The assist force can be transmitted while following the natural movement of both bones centering on the joints of the human body. For example, in the case of a joint such as a knee joint where bending motion is the main, the assist force is always centered on the joint axis of the human body without constraining the movement of the joint axis of the joint accompanying the bending and stretching movements of both bones. Added. In addition, in a ball joint joint, for example, a hip joint, a linear member arranged so that an assist force is applied in a bending / extension direction between bones connected to the hip joint is a part of a human body side centered on the joint center. Following the movement in each direction, it bends or twists. For example, the adduction / extraction motion centering on the hip joint is not restricted.

According to the present invention, by using a flexible linear member, it is possible to simulate a motor function centered on a joint such as an inherent muscle. Therefore, unlike conventional devices composed of rigid links, etc., the joint mobility can be maintained at each joint in the human body, and the joint of the wearer can be assisted with little or no restraining force or discomfort. You can apply power.

In the present invention, it is desirable to cover at least a part of the linear member with a cylindrical member. It is desirable that the cylindrical member has at least flexibility among flexibility and stretchability.

The flexibility of the cylindrical member means flexibility or flexibility that can follow the movement of the linear member. Moreover, the elasticity of a cylindrical member means the elasticity which can track the increase / decrease in the length of the spanning part of a linear member. Usually, it is sufficient if a cylindrical member having a length corresponding to the maximum spanning length is disposed and has a stretchability that can be reduced to a length corresponding to the minimum spanning length.

The linear member embedded in the human body moves within a predetermined range as the human body moves around the joint. There is a possibility that the linear member may directly contact and damage the surrounding human tissue. By covering the linear member with a cylindrical member (tube, sheath) from a material that does not cause adverse effects such as damage even if it comes into contact with surrounding human tissue, a human body within the range of movement of the linear member Prevents damage to tissue. In this way, various materials can be used as the linear member without being restricted by the adaptability to the human tissue.

In the present invention, it is desirable to dispose a damper in the transmission path of the tensile force between the actuator and the linear member. As the “damper”, for example, a flexible elastic body such as a coil spring, a torsion spring, a leaf spring, rubber, and other various elastic members can be used. The elastic member does not substantially elastically deform when a required tensile force is transmitted, and elastically deforms when a tensile force exceeding it is applied, so that the transmitted tensile force is a predetermined magnitude. Do not exceed this.

In the state where the actuator is stopped, there is a possibility that an external force acts from the joint side through the linear member. For example, in the case of a knee joint, the knee joint may be bent or extended unintentionally, for example, when the wearer trips over a step. In such a case, a large impact force acts on parts such as the linear member and the actuator, and these parts may be damaged. By disposing a damper, for example, a coil spring, on the transmission path of the tensile force, the impact force can be alleviated and adverse effects such as breakage of each part can be avoided.

In the present invention, in order to transmit the tensile force for assisting the movement in the second direction opposite to the first direction in the relative movement around the joint portion between the first and second parts, There may be a case where an elastic member is provided for use between the first part and the second part.

For example, a linear member that gives an assist force in a bending direction or an extension direction centered on a joint, and an elastic member that gives a restoring force for returning a bent state to an extended state or a returning force for returning an extended state to a bent state Can be used in combination. Similarly, a combination of a linear member that gives an assist force in the inversion direction or the abduction direction around the joint and an elastic member that gives a return force to return the inversion or abduction state to the original state Can be used. Also, a combination of a linear member that gives an assist force in the internal rotation direction or the external rotation direction around the joint and an elastic member that gives a return force for returning the internal rotation state or the external rotation state to the original state is used. be able to.

Here, as the “elastic member”, a flexible elastic body such as a tension coil spring, a compression coil spring, a torsion spring, a leaf spring, and rubber, and other various elastically deformable members such as elastic expansion and contraction are used. Can do.

In the present invention, various actuators can be used as the actuator. For example, what winds and unwinds a linear member by a rotational motion can be used. Moreover, the thing which pulls in and draws out a linear member by linear motion, and the thing which performs the tension | pulling operation | movement of a linear member by the expansion-contraction movement of an expansion-contraction member can be used.

Further, the actuator can be disposed on the surface of the first or second bone or inside the first or second bone.

On the other hand, as the actuator, a polymer actuator used as an artificial muscle or the like can be used. In this case, for example, a part of the linear member can be formed by a polymer actuator. As such a polymer actuator, for example, an actuator element having a dielectric layer made of PVC proposed in Japanese Patent Application Laid-Open No. 2015-122935 by the applicant of the present application can be used.

In addition, as a member (attachment method) used for attaching the linear member (first and second linear members) to the first and second parts so that the tensile force can be transmitted, various members can be used. Can be used. For example, nails, screws or bolts used to fix the linear member to the first part or the second part, belt-like members and lines used to fasten the linear member to the first part or the second part For example, an adhesive used to join the linear member to the first part or the second part, a suture member used to suture the linear member to the first part or the second part, and the like can be used.

In the present invention, an intramedullary nail may be inserted and fixed in the medullary cavity of a bone in order to configure an assist force transmission mechanism without placing an excessive burden on the joint, bone, etc. of the wearer. In this case, a linear member or an actuator can be attached to the intramedullary nail.

Next, by using the linear member, an assisting tensile force can be applied in both the first direction of the relative motion centered on the joint and the opposite second direction. For example, a pair of linear members or 2 in order to stretch and contract in opposite phases in order to apply a tensile force for assisting both the bending motion and the extension motion to the joint portion via the linear member. A set of linear members may be arranged. Further, in order to give an assisting force by a linear member to a relative motion centered on a joint such as a hip joint, for example, an adduction motion and an abduction motion, one set is set so that expansion and contraction are performed in opposite phases. These linear members or two sets of linear members may be arranged.

For this reason, in the present invention, when the linear member is the first linear member, the movement in the second direction opposite to the first direction in the relative motion centered on the joint portion is assisted. One or more flexible second lines for use in a spanning manner between the first and second parts so that a tensile force is transmitted to the first and second parts. It has a member. The actuator is coupled to the first and second linear members so that the length of the bridging portion between the first and second portions of the first and second linear members increases and decreases in reverse phase. The

Instead, the linear member is used as a bridging portion between the first and second parts, and a first bridging portion for transmitting a tensile force that assists the movement in the first direction in the relative motion, The bridge is formed between the first and second portions so that a second bridge portion for transmitting a tensile force that assists the movement in the second direction opposite to the first direction is formed. May be. In this case, the actuator is engaged with the linear member so that the lengths of the first and second bridging portions increase and decrease in opposite phases.

Further, in the present invention, the first linear member and the first actuator are arranged to assist the movement in the second direction in order to assist the movement in the first direction in the relative motion centered on the joint portion. In order to do so, the second linear member and the second actuator can be arranged.

The implantable motion assist device of the present invention can be used, for example, as a device that assists a bending / extension motion centered on the hip joint of the wearer, an internal / external rotation motion or an internal / external rotation motion, and a flexion / extension motion centered on the knee joint. it can. In addition, the implantable motion assist device of the present invention can be widely used for people who can move by themselves but who are unable to move normally and have different degrees of difficulty. Furthermore, it can also be used for a person who cannot perform an operation such as walking without exerting muscular strength.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram at the time of seeing the implantable walk assist device of Embodiment 1 to which this invention is applied from the human body front side. It is a schematic block diagram at the time of seeing the implantable assist apparatus of FIG. 1 from the human body left outer side. FIG. 3 is a schematic configuration diagram illustrating a state where the left hip joint and the left knee joint in an upright state in FIG. 2 are bent. It is explanatory drawing which shows the implantable knee joint assist mechanism of Embodiment 2 to which this invention is applied, and explanatory drawing of a linear motion actuator.

[Embodiment 1]
In Embodiment 1 shown in FIGS. 1 to 3, the present invention is applied to an implantable walking assist device including a hip joint motion assist unit and a knee joint motion assist unit.

(overall structure)
FIG. 1 is a schematic configuration diagram when the implantable walking assist device according to the first embodiment is viewed from the front side of the wearer. 2 is a schematic configuration diagram of an upright state when the implantable walking assist device is viewed from the left outer side, and FIG. 3 is a schematic configuration diagram illustrating a state in which the left hip joint and the left knee joint are bent from the upright state. The implantable walking assist device 1 (hereinafter simply referred to as “assist device 1”) is embedded in the wearer's body, in this example, the left leg 11, and the hip joint 12 associated with the walking motion of the left leg 11 and Assists the knee joint 13 in bending and stretching movements.

The assist device 1 is embedded in a portion of the left hip joint 12 and is embedded in a portion of the left knee joint 13 which is embedded in a portion of the left hip joint 12 and assists the bending motion of the front and rear during walking around the hip joint 12. A knee joint motion assist unit 4 that assists the bending motion of the front and rear during walking around the knee joint 13 is provided.

The assist device 1 includes, for example, a human body-mounted battery power source (not shown) and a control unit (not shown), and drive power from the battery power source to the hip joint motion assist unit 2, the knee joint motion assist unit 4 and the control unit. Is supplied. The control unit controls the driving of the hip joint motion assist unit 2 and the knee joint motion assist unit 4 in conjunction with the movement of the human body, for example, by a control method using a neural oscillator model. The present applicant has proposed such a control method in Japanese Patent Application Laid-Open No. 2015-44240.

(Hip joint assist unit)
The hip joint motion assist unit 2 includes an intramedullary nail 21 inserted into the medullary cavity of the femur 14, a screw screw 22 for fixing the intramedullary nail 21 to the femur 14, and an iliac bone 15 on the pelvis side, for example. A screw screw 23 to be fixed and a rotary actuator 24 for generating an assist force with a housing 24a fixed to the screw screw 23 are provided.

As shown in FIGS. 2 and 3, the hip joint assist unit 2 includes a front winding shaft 25 and a rear winding shaft 26 that are rotatably supported by a housing 24 a of the rotary actuator 24, and a thigh It has a screw screw 27 fixed to the upper end of the bone 14 and a first string 28 and a second string 29 which are flexible linear members. These first and

second cords

28 and 29 are, for example, narrow tape-like or belt-like cords.

The first string 28 is unwound from the front winding shaft 25 located on the front side of the human body and is stretched around a screw front end 27a located on the same side of the screw screw 27. Similarly, the second string 29 is unwound from the rear winding shaft 26 located on the rear side of the human body and is stretched around the screw rear end 27b located on the same side of the screw screw 27. Therefore, the first string 28 and the second string 29 are bridged between the pelvis-side iliac bone 15 and the femur 14 at positions around the human body with the hip joint 12 interposed therebetween.

In this example, the front take-up shaft 25 supported by the housing 24a fixed to the screw screw 23 fixed to the pelvis side functions as a part for bridging the first string 28 to the bone on the pelvis side. The screw front end 27a of the screw screw 27 on the side of the femur 14 functions as a part for spanning (fixing) the first string 28 to the femur 14. Similarly, the rear winding shaft 26 functions as a portion for bridging the second string 29 to the bone on the pelvis side, and the screw rear end 27b of the screw screw 27 on the femur 14 side is the second string. It functions as a part for spanning (fixing) 29 to the femur 14.

Here, the bridging portion 28 a between the front winding shaft 25 and the screw front end 27 a of the screw screw 27 in the first first cord 28 is covered with a flexible tube 31. The tube 31 has, for example, a bellows structure and can be expanded and contracted in the length direction. Similarly, a bridging portion 29 a between the rear winding shaft 26 and the screw rear end 27 b of the screw screw 27 in the second second string 29 on the rear side is covered with a flexible tube 32. The tube 32 also has a bellows structure, for example, and can be expanded and contracted in the length direction.

For example, a pinion 33 is coaxially fixed to the rotation shaft 24b of the rotary actuator 24. The front transmission gear 34 and the rear transmission gear 35 are engaged with the pinion 33 from the front-rear direction of the human body. The front transmission gear 34 is fixed to the front winding shaft 25 coaxially, and the rear transmission gear 35 is fixed to the rear winding shaft 26 coaxially.

For example, the first string 28 is wound around the front winding shaft 25 in the clockwise direction, and the second string 29 is wound around the rear winding shaft 26 in the opposite counterclockwise direction. For example, in the state of FIG. 2, when the rotary actuator 24 is driven and the rotary shaft 24b rotates in one direction, the first string 28 is wound around the front winding shaft 25 as shown in FIG. The length of the bridging portion 28a of the first string 28 spanned from the winding shaft 25 to the screw front end 27a of the screw screw 27 of the femur 14 is shortened. In other words, the distance from the front winding shaft 25 to the screw front end 27a is shortened.

As a result, the rotational force of the rotary actuator 24 is applied to the femur 14 via the first cord 28 as an assist force in the direction in which the femur 14 bends forward with respect to the pelvis centering on the joint center of the hip joint 12. Works. The tube 31 is stretchable and contracts as the length of the bridging portion 28a decreases, so that it does not interfere with the winding operation of the first string 28.

Further, as shown in FIG. 3, the rear second string 29 is unwound by the rotation of the rear winding shaft 26 in the same direction, and the length of the bridging portion 29a is increased. 14 does not interfere with the bending motion. The tube 32 expands accordingly when the bridging portion 29a becomes longer, so that the second string 29 is not exposed and does not come into contact with surrounding human tissue.

When the rotary actuator 24 is rotated in the reverse direction, the length of the bridging portion 28a of the front first string 28 is increased, and the length of the bridging portion 29a of the second second string 29 is shortened. As a result, the rotational force of the rotary actuator 24 acts on the femur 14 via the second string 29 in the direction in which the femur 14 extends backward with respect to the pelvis centering on the hip joint 12. Also in this case, each

tube

31 and 32 expands and contracts following the change in the length of the

bridging portions

28a and 29a, for example, returns from the state of FIG. 3 to the state of FIG.

Here, when an adduction motion or abduction motion, an internal rotation motion or an external rotation motion, or a combined motion thereof occurs in a site on the side of the femur 14 with the hip joint 12 as a center, the flexibility is increased. The first and

second cords

28 and 29 are bent or twisted following such movement. Therefore, it is possible to prevent the hip joint motion assist unit 2 from becoming an obstacle to the inward and outward motion. Further, if the rotary actuator 24 is driven and controlled so that the first and

second cords

28 and 29 are unwound and unwound in accordance with such an inner / outer rotation motion, the wearer does not feel restrained or uncomfortable. Inward and outward motion can be performed.

Furthermore, a flexible linear member such as a string is bridged so that one or both of the inner / outer rotation movement and the inner / outer rotation movement can be applied, and this bridge length is rotated. It can be increased or decreased by an actuator such as an actuator. In this way, it is possible to assist in the internal / external rotation and internal / external rotation.

The rotary actuator 24 includes, for example, an electric motor and a speed reducer that decelerates the output rotation and transmits it to the rotary shaft 24b. Further, the embedded position of the rotary actuator 24 is, for example, a position deviated upward from the left lateral position of the hip joint 12 so that the embedded space can be easily secured.

(Knee joint motion assist unit)
Next, the knee joint motion assist unit 4 includes the intramedullary nail 21 inserted into the medullary cavity of the femur 14 and a screw screw 42 for fixing the lower end portion 21b of the intramedullary nail 21 to the femur 14. The housing 44a is fixed to the intramedullary nail 41 inserted into the tibia 17, the screw screw 43 for fixing the upper end portion 41a of the intramedullary nail 41 to the tibia 17, and the screw screw 42 on the femur 14 side. And a rotary actuator 44 for generating assist force.

Further, the knee joint motion assist unit 4 is fixed to the front winding shaft 45 and the rear winding shaft 46 that are rotatably supported by the housing 44 a of the rotary actuator 44 and the upper end of the tibia 17. And a flexible first string 48 and a flexible second string 49.

The first string 48 is unwound from the front winding shaft 45 located on the front side of the human body and is stretched around the screw front end 47a located on the same side of the screw screw 47. Similarly, the second string 49 is unwound from the rear winding shaft 46 located on the rear side of the human body and is stretched around the screw rear end 47 b located on the same side of the screw screw 47. The first string 48 and the second string 49 are bridged between the femur 14 and the tibia 17 at positions around the human body with the knee joint 13 interposed therebetween.

The front winding shaft 45 functions as a member for bridging the first string 48 to the femur 14 side, and the screw front end 47a of the screw screw 47 on the tibia 17 side hangs the first string 48 on the tibia 17. It functions as a member for passing. Similarly, the rear winding shaft 46 functions as a member for bridging the second string 49 to the femur 14, and the screw rear end 47 b of the screw screw 47 on the tibia 17 side connects the second string 49. It functions as a member that spans the tibia 17.

The bridging portion 48 a from the front winding shaft 45 to the screw front end 47 a of the screw screw 47 in the front first string 48 is covered with a flexible tube 51. The tube 51 has, for example, a bellows structure and can be expanded and contracted in the length direction. Similarly, a bridging portion 49 a between the rear winding shaft 46 and the screw rear end 47 b of the screw screw 47 in the rear second string 49 is covered with a flexible tube 52. The tube 52 also has a bellows structure, for example, and can be expanded and contracted in the length direction.

A pinion 53 is coaxially fixed to the rotation shaft 44 b of the rotary actuator 44. A front transmission gear 54 and a rear transmission gear 55 are engaged with the pinion 53 from the front-rear direction of the human body. The front transmission gear 54 is fixed coaxially to the front winding shaft 45, and the rear transmission gear 55 is fixed coaxially to the rear winding shaft 46.

For example, the first string 48 is wound around the front winding shaft 45 clockwise, and the second string 49 is wound around the rear winding shaft 46 counterclockwise. For example, when the rotary actuator 44 is driven and the rotary shaft 44b rotates in one direction in the state of FIG. 2, the second string 49 is unwound from the rear winding shaft 46 as shown in FIG. The length of the bridging portion 49a of the second string 49 spanned between the posterior front winding shaft 46 and the screw rear end 47b of the screw screw 47 of the tibia 17 is increased.

As a result, the rotational force of the rotary actuator 44 acts on the tibia 17 via the second string 49 as an assisting force in the direction in which the tibia 17 bends backward with respect to the femur 14 around the knee joint 13. . The tube 52 is stretchable and extends according to the increase in the length of the bridging portion 49 a and does not interfere with the winding operation of the second string 49.

Further, the front first string 48 is unwound by the rotation of the front winding shaft 45 in the same direction, the length of the spanning portion 48a is shortened, and does not interfere with the extension movement of the tibia 17. Since the tube 51 contracts accordingly when the span 48a becomes longer, the first string 48 is not exposed and does not come into contact with the surrounding human tissue to be damaged.

When the rotary actuator 44 is rotated in the reverse direction in the state of FIG. 3, the length of the bridging portion 48a of the front first string 48 is shortened as shown in FIG. The length of the bridging portion 49a is increased. As a result, the rotational force of the rotary actuator 44 acts on the tibia 17 via the first string 48 in the direction in which the tibia 17 extends forward with respect to the femur 14 about the knee joint 13. Also in this case, each

tube

51, 52 expands and contracts following the change in the length of the

bridging portions

48a, 49a.

The rotary actuator 44 includes, for example, an electric motor and a speed reducer that decelerates the output rotation and transmits it to the rotating shaft 44b. Further, the position where the rotary actuator 44 is embedded is, for example, a position deviated upward from the left lateral position of the knee joint 13 so that the embedded space can be easily secured.

(Modification of Embodiment 1)
In the above example, in the hip joint 12 and the knee joint 13, the first and

second strings

28, 29, 48, and 49 are arranged one by one on the front and rear sides thereof. A plurality of strings can be used as the first and second strings, respectively. Further, when one or a plurality of laces functioning as the first and second laces are routed so that the front

side bridging portions

28a and 48a become longer, the rear

side bridging portions

29a and 49a become shorter. It is also possible to make it.

Further, for example, in the knee joint 13, an elastic member such as a coil spring or a torsion spring is used instead of the second string 49 on the bending side, and a compressive force acts between the femur 14 and the tibia 17. It is also possible to hang it over. For example, it is possible to assist the extension operation of the knee joint by pulling the string in a direction in which the length is shortened, and assist the bending operation of the knee joint by the compressive force of the elastic member. Moreover, it is possible to use a string and an elastic member also on the hip joint 12 side.

Furthermore, in the knee joint 13, the first string 48 for extension on the front side is bridged between the femur 14 and the tibia 17. Alternatively, the first string 48 can be spanned between the first femur 14 and the patella 18 so that the tibia 17 extends through the patella 18.

Furthermore, in the above example, assist force is generated using a rotary actuator. Instead of this, it is also possible to use polymer actuators used for artificial muscles and the like. In this case, for example, a part of the first and

second strings

28, 29, 48, 49 is formed by a polymer actuator, and is stretched and contracted in the string length direction so that the bridging

portions

28a, 29a, 48a, The length of 49a can be increased or decreased.

In the above example, the wearer's bone is reinforced using an intramedullary nail. When the wearer's bone is strong, the actuator, the first string, the second string, and the like can be fixed to each bone without using the intramedullary nail.

[Embodiment 2]
FIG. 4A is an explanatory view showing a knee joint assist mechanism according to Embodiment 2 to which the present invention is applied, and FIG. 4B is an explanatory view showing a linear actuator. The knee joint assist mechanism 100 includes an extension assist unit 110 that is embedded in the left leg of the wearer and assists an extension movement in the front-rear direction of the human body around the left knee joint 13, and a bending assist unit 130 that assists the bending movement. And a human-mounted control unit 150 incorporating a battery power source and a control mechanism.

The control unit 150 controls the driving of the extension assist unit 110 and the bending assist unit 130 in conjunction with the movement of the human body by a control method using a neural oscillator model, for example (see Japanese Patent Application Laid-Open No. 2015-44240). For example, the control unit 150 assists the knee joint motion by alternately driving and controlling the extension assist unit 110 and the bending assist unit 130 in the walking motion.

The extension assist unit 110 is a flexible wire 111 used to transmit a tensile force for assisting an extension movement to one of the femur 14 and the tibia 17, which in this example is the tibia 17, connected to the knee joint 13. And a linear motion actuator 120 attached to the femur 14 in order to give a tensile force to the wire 111.

The lower end 111 a of the wire 111 is fixed to the front part of the upper end of the tibia 17. The wire 111 extends upward via the patella 18, and the upper end 111 b of the wire 111 is connected to the linear motion actuator 120 side. The pulling amount of the wire 111 by the linear actuator 120 is about 60 mm in order to extend the knee joint 13 from 90 ° to 0 °. A linear actuator with a stroke exceeding this may be used.

The fixing part 112 for fixing the lower end 111a of the wire 111 to the tibia 17 can be a fixing part by a nail, a screw, a bolt, a fastening band or the like, or a fixing part by adhesion or stitching. A portion of the wire 111 that comes into contact with human tissue is covered with a flexible and stretchable cylinder 113. Thereby, it is possible to prevent the human tissue from being damaged by the moving wire 111.

The linear motion actuator 120 is, for example, arranged along the outer side surface of the femur 14 and is fixed to the femur 14. For example, the linear actuator 120 can be manufactured as the intramedullary nail 21 in the first embodiment and embedded in the femur 14.

Referring to FIG. 4B, the linear motion actuator 120 is a ball screw type actuator, and includes an elongated cylindrical case 121, a ball screw shaft 122 extending coaxially therein, and a screw on the ball screw shaft 122. A ball screw 123 and a servo motor 124 for rotating the ball screw 122 are provided. In some cases, the required torque is secured by combining a motor and a reduction gear. The ball screw shaft 122 is supported by the cylindrical case 121 in a rotatable state, and the ball screw 123 is supported by the cylindrical case 121 in a state that it can slide along the ball screw shaft 122 and cannot rotate. . When the servo motor 124 is driven to rotate the ball screw shaft 122, the ball screw 123 slides in the front-rear direction indicated by the arrow 126 along the ball screw shaft 122.

The upper end 111b of the wire 111 is connected to the ball screw 123 via a coil spring 125 that functions as a damper. When the ball screw 123 slides backward, the wire 111 is pulled and pulled (the wire span length from the tip position 120a of the linear actuator 120 to the lower end 111a of the wire 111 connected to the tibia 17 side. Becomes shorter.) A tensile force in a direction of extending the tibia 17 forward of the human body with respect to the femur 14 around the knee joint 13 acts as an assist force via the wire 111. When the ball screw 123 is slid forward, the wire 111 is loosened and the tension of the tibia 17 is released. The wearer can freely bend the tibia 17 backward with respect to the femur 14 around the knee joint 13.

Referring back to FIG. 4A again, the bending assist unit 130 has the same structure as the extension assist unit 110, but the mounting position is different. The bending assist unit 130 is a flexible wire 131 used for transmitting a tensile force for assisting a bending motion to one bone connected to the knee joint 13, in this example, the tibia 17 side, and the tensile force applied to the wire 131. And a linear motion actuator 140 for providing

The lower end 131a of the wire 131 is fixed to the rear part of the upper end of the tibia 17 or the rib 19. For example, the lower end 131a of the wire 131 is fixed to the biceps femoris attachment portion or the posterior cruciate ligament attachment portion in the tibia 17. The upper end 131b of the wire 131 is connected to the linear actuator 140 side. The linear actuator 140 is disposed along the inner side surface of the femur 14 and is fixed to the femur 14, for example.

When the linear actuator 140 is driven and the ball screw is slid rearward, the wire 131 is pulled. A tensile force in the direction of bending the tibia 17 backward with respect to the femur 14 around the knee joint 13 acts as an assist force via the wire 131. When the ball screw is slid forward, the wire 131 is loosened and the tensile force is released.

[Other embodiments]
The present invention is an implantable motion assist device that is attached to a shoulder joint part to assist in operations other than walking, for example, raising and lowering of an arm, and is attached to an elbow joint part to assist in operations such as bending and stretching of the elbow. It can be used as an implantable motion assist device. Further, it can be used as an apparatus for assisting operation by attaching to a joint part of a human body other than these.

Claims

An implantable motion assist device that is implanted and used in the body to assist the movement of the wearer's joints,
When a pair of bones that perform relative motion around the joint are first and second bones, the first bone or a tendon connected to the first bone is referred to as a first part, If the tendon connected to the second bone or the second bone is called the second part,
A flexible linear member used to transmit a tensile force for assisting movement in the first direction in the relative movement between the first and second portions;
An implantable motion assist device having an actuator that applies the tensile force to the linear member.
In claim 1,
A cylindrical member covering at least a part of the linear member;
The tubular member is an implantable motion assist device having at least flexibility among flexibility and stretchability.
In claim 1,
An implantable motion assist device having a damper disposed in a transmission path of the tensile force between the actuator and the linear member.
In claim 1,
In order to transmit a tensile force between the first and second parts to assist the movement in the second direction opposite to the first direction in the relative movement, the first part and the second part An implantable motion assist device having an elastic member for use by being bridged between second portions.
In claim 1,
The actuator is an implantable motion assist device that is a rotational drive mechanism, a linear motion mechanism, or a telescopic mechanism that applies the tensile force to the linear member by rotational motion, linear motion, or telescopic motion.
In claim 5,
The implantable movement assist device, wherein the actuator is attached at the surface or inside of the first bone or the second bone.
In claim 1,
The implantable motion assist device, wherein the actuator is a stretchable polymer actuator forming a part of the linear member.
In claim 1,
In order to attach the linear member to the first and second parts so that the tensile force can be transmitted,
Nails, screws or bolts used to fix the linear member to the first part or the second part,
A belt-like member used for fastening the linear member to the first part or the second part;
An adhesive used to join the linear member to the first part or the second part; and
An implantable motion assist device having at least one of suturing members used for suturing the linear member to the first part or the second part.
In claim 1,
An intramedullary nail used for insertion and fixation in the medullary cavity of at least one of the first and second bones;
The intramedullary nail is an implantable motion assist device that is an attachment portion of at least one of the linear member and the actuator.
In claim 1,
The linear member includes a portion used as a bridging portion spanned between the first and second portions,
The implantable motion assist device that is engaged with the linear member so that the actuator can increase or decrease the length of the bridging portion.
In claim 10,
When the linear member is a first linear member and the tensile force is referred to as a first tensile force,
In order to transmit a second tensile force that assists the movement in the second direction opposite to the first direction in the relative movement to the first and second parts, the first and second A flexible second linear member for use between the parts,
The actuator includes the first and second linear members such that a length of a bridging portion between the first and second portions of the first and second linear members increases and decreases in an opposite phase. An implantable motion assist device engaged with a member.
In claim 10,
When the bridging portion of the linear member is called a first bridging portion and the tensile force is called a first tensile force,
The linear member includes a first bridging portion and a second bridging portion for transmitting a second tensile force that assists movement in a second direction opposite to the first direction. Is a linear member used across between the first and second parts so that is formed,
The actuator is an implantable motion assist device that is engaged with the linear member so that the lengths of the first and second bridging portions increase and decrease in opposite phases.
In claim 1,
A cylindrical member covering at least a part of the linear member;
A damper disposed in a transmission path of the tensile force between the actuator and the linear member, and an intramedullary nail used for insertion and fixation in each medullary cavity of the first and second bones And
The cylindrical member has at least flexibility among flexibility and stretchability,
The joint is a knee joint;
The actuator is a rotary actuator to be used by being attached to the intramedullary nail inserted and fixed to the femur which is the first bone,
One end of the linear member is an implantable motion assist device that is an end for connecting to the intramedullary nail inserted and fixed to the tibia, which is the second bone.
In claim 1,
The actuator is an actuator for use by being attached to one of the first and second parts,
One end of the linear member is an end for connecting to the other of the first and second portions,
The implantable motion assist device engaged with the linear member so that the actuator can pull the other end of the linear member.
In claim 13,
An intramedullary nail used for insertion and fixation in the medullary cavity of at least one of the first and second bones;
An implantable motion assist device in which the actuator is incorporated in the intramedullary nail.
In claim 13,
A flexible material used to transmit a second tensile force between the first and second parts to assist movement in a second direction opposite to the first direction in the relative movement. A second linear member;
A second actuator that applies the second tensile force to the second linear member;
The second actuator is an actuator used by being attached to one of the first and second parts,
One end of the second linear member is an end for connecting to the other of the first and second portions,
The implantable motion assist device that is engaged with the second linear member so that the second actuator can pull the other end of the second linear member.
In claim 1,
A cylindrical member covering at least a part of the linear member;
A damper disposed in the transmission path of the tensile force between the actuator and the linear member;
The cylindrical member has at least flexibility among flexibility and stretchability,
The joint is a knee joint;
The actuator is a linear motion actuator to be used by being attached to the surface or inside of the femur as the first bone,
One end of the linear member is an end for connecting to the tibia which is the second bone,
The linear motion actuator is an implantable motion assist device in which a linear motion portion of the linear motion actuator is connected to the other end of the linear member via the damper.