JP5095582B2 - Walking assist device - Google Patents

Description

  The present invention relates to a walking assistance device that assists a user (person) in walking.

Conventionally, as this type of walking assist device, for example, Patent Document 1 discloses an upper thigh attachment member that is attached to the upper thigh part, and a lower thigh attachment member that is rotatably attached to the upper thigh attachment member and attached to the lower thigh part. A walking assistance device comprising: This walking assistance device includes a motor attached to the upper thigh attachment member, a socket attached to the lower thigh attachment member, a ball screw that is screwed into a spiral hole of the socket, and a flexible joint that connects the motor shaft and the ball screw. It has a drive mechanism configured. Then, the crus attachment member is bent with respect to the crus attachment member by changing the distance between the lower end of the flexible joint and the socket by the forward and backward movement of the ball screw with respect to the socket. Thereby, the walking handicapped person can rotate the knee joint part and can obtain a stable gait.
JP 2002-191654 A

  However, in the walking assistance device disclosed in Patent Document 1, since the motor shaft of the motor attached to the upper thigh attachment member and the ball screw are connected in series via the flexible joint, the drive mechanism However, there was a problem that the axis became longer. Further, since the crus attachment member is bent with respect to the crus attachment member due to the forward and backward movement of the ball screw with respect to the socket, there is a problem that the stroke of the ball screw becomes long and the ball screw becomes a long axis.

  This invention makes it the subject to provide the walk auxiliary | assistance apparatus which can aim at shortening of a drive mechanism and a ball screw in what used the ball screw in view of the above point.

  In order to solve the above-described problems, the present invention provides a load transmission unit that transmits a load that supports a part of the weight of the user to the trunk of the user, and a foot mounting unit that is mounted on the user's foot. And a leg link connecting the foot mounting part to the load transmitting part, the leg link extending from the load transmitting part via a first joint, and the foot mounting part. A lower link member extending through the second joint; and a third joint for flexibly connecting the upper link member and the lower link member, and further for driving the third joint. In the walking assist device provided with the drive mechanism, the drive mechanism is supported by a casing that is swingably connected to the upper link member, and is rotated by a hollow electric motor, and held by the nut member Screwed into the nut member via the ball A linear motion actuator comprising a linear motion output shaft that is inserted in a through hole formed in a hollow inner rotor of a hollow electric motor, and a joint shaft of a third joint on the lower link member The third joint is provided with a translational force output from the linear motion output shaft of the linear motion actuator via the crank arm. It is comprised so that it may convert into this rotational driving force.

  According to the present invention, the linear motion output shaft is inserted through the through hole formed in the hollow inner rotor of the hollow electrical motor that rotationally drives the nut member, and the hollow electrical motor is disposed around the linear motion output shaft. The Therefore, unlike the walking assistance device described in Patent Document 1, it is not necessary to arrange an electric motor in series at the end of the linear motion output shaft (ball screw), so that the drive mechanism can be shortened. It becomes possible. Further, the drive mechanism applies a rotational driving force to the third joint by rotating the crank arm fixed to the lower link member coaxially with the joint shaft of the third joint by the forward and backward movement of the linear motion output shaft. Therefore, the stroke of the linear motion output shaft can be shortened compared to the walking assistance device described in Patent Document 1, and the linear motion output shaft can be shortened.

  In the present invention, it is desirable that the nut member and the hollow inner rotor are fixedly connected. According to this, when the nut member and the hollow inner rotor are fixedly connected, for example, the configuration is compared with a case where a speed change member, a sliding member, or the like is interposed between the nut member and the hollow inner rotor. Simplified and excellent drive transmission efficiency. Furthermore, the nut member and the hollow electric motor can be disposed close to each other, and the linear motion actuator can be reduced in size.

Further, in the present invention, the linear actuator is that is housed inside the upper link member. According to this, since the noise source including the hollow electric motor is accommodated and shielded in the upper link member, leakage of noise to the outside can be suppressed. Further, since the linear actuator does not jump out of the upper link member, the user can easily attach and detach the walking assist device without being caught.

  A walking assistance device A according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the walking assist device A includes a seating unit 1 as a load transmission unit, and a pair of left and right foot mounting units 2 and 2 mounted on the foot of each leg of a user (not shown). And a pair of left and right leg links 3 and 3 for connecting the respective foot mounting portions 2 and 2 to the seating portion 1. The left and right foot mounting portions 2 and 2 have the same structure that is symmetrical to each other. The left and right leg links 3, 3 also have the same structure that is symmetrical to each other. In the description of the present embodiment, the left-right direction of the walking assist device A is the left-right direction of the user who wears the foot mounting portions 2, 2 on the foot (a direction substantially perpendicular to the paper surface in FIG. 1). means.

  Each leg link 3 includes an upper link member 5 extending downward from the seating portion 1 via the first joint 4 and a lower side extending upward from the foot mounting portion 2 via the second joint 6. The link member 7 is configured by a third joint 8 that connects the upper link member 5 and the lower link member 7 so as to be able to bend and extend in the middle between the first joint 4 and the second joint 6.

  The walking assistance device A includes a drive mechanism 9 for driving the third joint 8 for each leg link 3. The drive mechanism 9 of the left leg link 3 and the drive mechanism 9 of the right leg link 3 have the same symmetrical structure. In FIG. 1, the drive mechanism 9 of the right leg link 3 is partially omitted for easy understanding of the drawing.

  The seat portion 1 includes a saddle-shaped seat portion 1a that is seated so that the user straddles it (positioned between the bases of both legs of the user), and a base frame 1b that is mounted on the lower surface of the seat portion 1a. And a waist pad portion 1c attached to the rear end portion of the base frame 1b (the rising portion rising upward on the rear side of the seat portion 1a).

  The first joint 4 of each leg link 3 is a joint having rotational degrees of freedom (two degrees of freedom) around two joint axes in the front-rear direction and the left-right direction. More specifically, each first joint 4 includes an arcuate guide rail 11 assembled to the base frame 1 b of the seating portion 1. A slider 12 fixed to the upper end of the upper link member 5 of each leg link 3 is movably engaged with the guide rail 11 via a plurality of rollers 13 pivotally attached to the slider 12. Yes. For this reason, each leg link 3 has an axis in the left-right direction passing through the center of curvature 4 a of the guide rail 11 (more specifically, an axis in a direction perpendicular to the plane including the arc of the guide rail 11). As a joint axis, a swinging motion in the front-rear direction (back-and-forth swinging motion) can be performed around the first joint axis.

  The guide rail 11 is pivotally supported on the rear upper end portion of the support frame 1b of the seating portion 1 via a support shaft 4b with its axis oriented in the front-rear direction, and can swing around the axis of the support shaft 4b. It is said that. As a result, each leg link 3 uses the axis of the support shaft 4b as the second joint axis of the first joint 4, and swings in the left-right direction around the second joint axis (inner / outer movement). It is possible to do. In the present embodiment, the second joint axis of the first joint 4 is a joint axis common to the first joint 4 on the right side and the first joint 4 on the left side.

  As described above, the first joint 4 is configured such that each leg link 3 can perform a swinging motion around two joint axes in the front-rear direction and the left-right direction.

  Note that the degree of freedom of rotation of the first joint is not limited to two. For example, the first joint may be configured to have rotational degrees of freedom (three degrees of freedom) around three joint axes. Alternatively, for example, the first joint may be configured to have only a rotational degree of freedom (one degree of freedom) around one joint axis in the left-right direction.

  Each foot mounting portion 2 includes a shoe 2a to be put on each foot of the user and a connecting member 2b protruding upward from the shoe 2a, and each leg of the user becomes a standing leg (supporting leg) Then, it is grounded through the shoe 2a. And the lower end part of the lower link member 7 of each leg link 3 is connected to the connecting member 2 b via the second joint 6. In this case, the connecting member 2b is integrally provided with a flat plate-like portion 2bx disposed below the insole 2c in the shoe 2a (between the bottom of the shoe 2a and the insole 2c). Then, when the foot mounting portion 2 is grounded, the connecting member 2b has a part of the floor reaction force that acts on the foot mounting portion 2 from the floor (at least a part of the weight of the walking assist device A and the user). Comparison including the flat portion 2bx so that a translational force large enough to support the combined weight can be applied to the leg link 3 via the connecting member 2b and the second joint 6. It is formed of a highly rigid member. The foot mounting portion 2 may be provided with, for example, a slipper shape instead of the shoe 2a.

  In the present embodiment, the second joint 6 is constituted by a free joint such as a ball joint, and is a joint having a degree of freedom of rotation around three axes. However, the second joint may be, for example, a joint having a degree of freedom of rotation around two axes in the front-rear and left-right directions, or around two axes in the up-down and left-right directions.

  The third joint 8 is a joint having a degree of freedom of rotation about one axis in the left-right direction, and has a support shaft 8 a that supports the upper end portion of the lower link member 7 at the lower end portion of the upper link member 5. The axis of the support shaft 8a is substantially parallel to the first joint axis of the first joint 4 (the axis in the direction perpendicular to the plane including the arc of the guide rail 11). The axis of the support shaft 8 a is the joint axis of the third joint 8, and the lower link member 7 is rotatable relative to the upper link member 5 around the joint axis. As a result, the leg link 3 can bend and stretch at the third joint 8.

  Each drive mechanism 9 is configured so that the foot mounting portion 2 is grounded so that a load (upward translational force) that supports a part of the weight of the user seated on the seat portion 1 is applied to the user from the seat portion 1. A rotational driving force (torque) in the extending direction of the leg link 3 is applied to the third joint 8 of the leg link 3. The drive mechanism 9 is mounted on the upper link member 5 of the leg link 3, and includes a linear motion actuator 14 having a linear motion output shaft (ball screw) 14a and power (linear motion) output from the linear motion output shaft 14a. It comprises a power transmission mechanism 15 that converts a translational force in the axial direction of the output shaft 14 a into a rotational driving force and applies it to the third joint 8. The upper link member 5 is mounted with accessory parts (not shown) such as a power supply battery 5 a and a harness arranged in parallel above the drive mechanism 9.

  Hereinafter, details of the drive mechanism 9 will be described with reference to FIGS.

  As shown in FIG. 2, the upper link member 5 on which the drive mechanism 9 is mounted has a hollow structure in which an end portion on the third joint 8 side (hereinafter referred to as a knee side end portion) is opened. Then, the linear motion actuator 14 of the drive mechanism 9 extends to a position closer to the end of the first joint 4 (hereinafter referred to as the crotch end), and the power transmission mechanism 15 is closer to the crotch end of the upper link member 5. Are housed inside the upper link member 5 respectively from the point to the point near the knee side end.

  The linear actuator 14 is a hollow electric motor 16 as a rotary actuator, and a ball screw mechanism for converting a rotational driving force (torque) output from the hollow electric motor 16 into a translational force in the axial direction of the linear output shaft 14a. And a casing 17 having a substantially rectangular tube shape. The casing 17 is adjacent to the crotch side of the hollow electric motor 16 and the axial center of the linear motion output shaft 14a penetrating through the inside thereof is substantially oriented in the longitudinal direction of the upper link member 5. It is arranged at a position near the crotch end.

  As shown in FIG. 3, a pair of bearings 18a are incorporated at both ends of the casing 17 in a direction orthogonal to the axis of the linear motion output shaft 14a (a direction substantially perpendicular to the paper surface of FIG. 2). Bearing members 18, 18 are mounted. These bearing members 18, 18 are fixed to the housing 17 so that the respective bearings 18a face each other coaxially.

  A support shaft 19 protruding from the inner wall of the upper link member 5 so as to have an axis parallel to the joint axis of the third joint 8 is fitted into the inner ring of the bearing 18a of each bearing member 18. ing. Thus, the housing 17 is supported by the upper link member 5 so as to be swingable around the axis of the support shaft 19. Hereinafter, the support shaft 19 is also referred to as a swing shaft 19.

  The main part of the ball screw mechanism is accommodated in the housing 17. In the present embodiment, the linear motion output shaft 14a is a screw shaft of a ball screw mechanism, and a helical thread groove 14aa is formed on the outer peripheral surface thereof. The ball screw mechanism includes a cylindrical nut member 20 that is coaxially fitted to the linear motion output shaft 14a, and a plurality of nut members 20 that are held on the inner peripheral surface of the nut member 20 and engaged with the screw grooves 14aa. And the nut member 20 and the ball 21 are accommodated in the housing 17. On the inner peripheral surface of the nut member 20, a thread groove engaged with the ball 21 is formed. Then, by rotating the nut member 20 around the axial center with respect to the linear output shaft 14a, the ball 21 rolls along the screw groove 14aa, and the linear output shaft 14a moves relative to the nut member 20. To move in the axial direction.

  The nut member 20 is disposed inside the housing 17 so that the central portion in the axial center direction is located between the swing shafts 19 and 19. An output shaft 16a (described later) of the hollow electric motor 16 is fixed to one end portion (crotch side end portion) of the nut member 20 in the axial direction. The output shaft 16a is coaxial with the nut member 20 and has a clearance between the output shaft 16a and the output shaft 16a. The output shaft 16a is extrapolated to the output shaft 14a. It is located inside the housing 17.

  And between the outer peripheral surface of the other end (the end opposite to the output shaft 16a) of the nut member 20 and the inner peripheral surface of the housing 17, and the outer peripheral surface of the output shaft 16a near the nut member 20 and the housing. Between the inner peripheral surface of the body 17, bearings 22 a and 22 b coaxial with the nut member 20 are interposed. As a result, the nut member 20 and the output shaft 16a are supported by the housing 17 via the bearings 22a and 22b so that the nut member 20 and the output shaft 16a can rotate integrally around their axes (around the axis of the linear output shaft 14a). Yes.

  In addition, in this embodiment, although the nut member 20 and the output shaft 16a are separate structures, you may comprise the nut member 20 and the output shaft 16a integrally.

  Here, when the nut member 20 is rotated, the linear motion output shaft 14 a works in the axial direction, so that the axial force (thrust force) acts on the nut member 20. For this reason, in this embodiment, the bearings 22a and 22b are constituted by angular bearings. In this case, a jaw portion 20 a formed on the outer peripheral surface of the nut member 20 is in contact with an end surface on the bearing 22 b side of both end surfaces of the inner ring of the bearing 22 a in the axial direction. Further, an annular cap member 23 attached to the end portion on the knee side of the housing 17 is in contact with the end face on the opposite side to the bearing 22b of both end faces of the outer ring of the bearing 22a in the axial direction. A jaw portion 16aa formed on the outer peripheral surface of the output shaft 16a is in contact with an end surface on the bearing 22a side of both end surfaces in the axial direction of the inner ring of the bearing 22b. Further, a jaw portion 17a formed on the inner peripheral surface of the crotch side end portion of the housing 17 is brought into contact with the end surface opposite to the bearing 22a of both end surfaces of the outer ring of the bearing 22b in the axial direction. Yes. Thereby, the casing 17 receives the thrust force acting on the nut member 20 when the nut member 20 rotates through the bearings (angular bearings) 22a and 22b. In this case, the nut member 20 and the output shaft 16a function as an inner collar interposed between the inner rings of the bearings 22a and 22b.

  A cylindrical outer collar 24 inserted on the nut member 20 is interposed between the outer ring of the bearing 22a and the outer ring of the bearing 22b. The outer ring of the bearing 22 a is sandwiched between the outer collar 24 and the annular cap member 23, and the outer ring of the bearing 22 b is sandwiched between the outer collar 24 and the jaw portion 17 a of the housing 17. .

  Incidentally, bearing members 18 and 18 for swingably supporting the casing 17 on the swing shafts 19 and 19 can be disposed outside the outer collar 24. However, in this case, the width of the casing 17 in the axial direction of the swing shafts 19, 19, that is, the width in the left-right direction increases, and the width in the left-right direction of the upper link member 5 and the linear actuator 14 also increases. .

  Therefore, in the present embodiment, at the mounting location of each bearing member 18 (location within the interval between the bearings 22a and 22b), as shown in FIG. Openings 17b and 24a are formed respectively. Each bearing member 18 is attached to the casing 17 so that each bearing member 18 is accommodated in the openings 17b and 24a and is close to the outer peripheral surface of the nut member 20. More specifically, the cylindrical outer collar 24 is formed with an opening 24a by notching a part of its side wall. In addition, an opening 17b is formed in the side wall of the rectangular tubular casing 17 so as to cut out substantially the same shape as the outer shape of the bearing member 18. The bearing member 18 is disposed in the openings 17 b and 24 a and is bolted to the housing 17. Thus, the width of the casing 17 (width in the axial direction of the swing shaft 19) at the mounting position of each bearing member 18 is made as small as possible so that each bearing member 18 does not protrude from the outer surface of the casing 17. It is trying to become.

  As shown in FIG. 4, the motor housing 25 that houses the hollow electric motor 16 is fixed to the housing 17 by bolting so as to be adjacent to the knee side end of the housing 17. Thereby, the motor housing 25 is arrange | positioned so that a user's thigh part may be adjoined. The hollow electric motor 16 has a through hole formed along an axis, a hollow output shaft 16a that also serves as an inner rotor, and a multi-pole magnetized rotor magnet 16b that is fixed to the outer peripheral surface of the output shaft 16a. The stator 16c is fixed to the inside of the motor housing 25 so as to face the rotor magnets 16b. Thus, since the output shaft 16a located in the center of the hollow electric motor 16 is disposed coaxially with the linear motion output shaft 14a, the specific direction of the outer shape of the hollow electric motor 16 with respect to the linear motion actuator 14 is determined. Thus, the upper link member 5 is slimmed as a whole. Therefore, it is possible to reduce the lateral overhang by the hollow electric motor 16, to reduce the moment of inertia around the trunk axis of the user, and to reduce the possibility of hindering the user's walking. Can do.

  Further, although not shown in detail in the motor housing 25, a magnetic encoder 26 for detecting the rotation angle and rotation direction of the output shaft 16a is also incorporated, and the hollow electric motor 16 is integrated with the encoder 26. ing. A hollow rotor separated from the output shaft 16a is provided, and a reduction gear for obtaining a high rotational driving force (torque) from the output shaft 16a by reducing the rotational speed of the rotor with a gear or the like is incorporated in the motor housing 25. Also good. In this case, it is preferable that the hollow electric motor 16, the encoder 26 and the speed reducer are integrated and accommodated in the motor housing 25.

  As described above, the crotch side end of the output shaft 16a of the hollow electric motor 16 is fixed to the nut member 20 so as to be coaxial with the linear motion output shaft 14a. More specifically, the output shaft 16a is connected to the knee side end portion of the nut member 20 via the dog portion. Thereby, the rotational driving force output from the output shaft 16a of the hollow electric motor 16 is transmitted to the nut member 20 that rotates integrally with the output shaft 16a, and the linear output shaft 14a follows the axial direction thereof. It will be driven to move to. In other words, the rotational driving force of the hollow electric motor 16 is converted into the translational force in the axial direction of the linear motion output shaft 14a via the ball screw mechanism.

  By the way, for example, it is possible to extend the crotch side end portion of the linear motion output shaft 14a and rotate the nut member 20 by the so-called pulley-belt type rotation transmission mechanism with the rotational driving force of the electric motor arranged in parallel with the extending portion. It is. However, in this case, since the crotch side end portion of the linear motion output shaft 14a is stretched, there is a disadvantage that the linear motion output shaft 14a is elongated. Further, since the outer shape of the electric motor arranged in parallel with the extending portion of the linear motion output shaft 14a protrudes in one direction with respect to the axial center of the linear motion output shaft 14a, the protruding portion is formed on the outer shape of the upper link member 5. The disadvantage that it occurs.

  When the output shaft 16a of the hollow electric motor 16 is rotated, the linear motion output shaft 14a moves in the axial direction, so that the axial force (thrust force) acts on the output shaft 16a. Therefore, it is preferable to support the output shaft 16a via a pair of angular bearings. However, in this embodiment, in order to reduce the number of bearings and shorten the axis of the linear actuator 14, the bearing 22b that supports the nut member 20 that rotates integrally with the output shaft 16a is supported by the output shaft 16a. It is also used as one of the pair of angular bearings. A bearing 27 that is the other angular bearing is arranged inside the motor housing 25.

  More specifically, the bearing 27 is interposed coaxially with the output shaft 16 a between the outer peripheral surface of the crotch end of the output shaft 16 a and the inner peripheral surface of the motor housing 25. And the jaw part 16aa formed in the outer peripheral surface of the output shaft 16a is contact | abutted to the end surface of the knee side among the both end surfaces of the axial direction of the inner ring | wheel of the bearing 27. As shown in FIG. Further, a jaw portion 25 a formed on the inner peripheral surface of the motor housing 25 is in contact with an end surface on the crotch side of both end surfaces in the axial direction of the outer ring of the bearing 27. As a result, the thrust force acting on the output shaft 16a is received by the housing 17 and the motor housing 25 via the bearings 222b and 27.

  As shown in FIGS. 3 and 4, a linear motion output shaft is provided at an end portion of the linear motion output shaft 14 a protruding from the inside of the housing 17 to the crotch side (hereinafter referred to as a rear end portion of the linear motion output shaft 14 a). A stopper member 28 for limiting the amount of movement 14a is mounted. The stopper member 28 is externally inserted into the male screw portion 14ab and a nut 28a screwed into the male screw portion 14ab projecting from the end surface of the rear end portion of the linear motion output shaft 14a. It comprises a metal washer 28b and an annular buffer member 28c sandwiched between the end face of the rear end portion and the nut 28a. The annular cushioning member 28c is made of an elastic material such as urethane rubber, and is interposed between the washer 28b and the nut 28a.

  In this case, the outer diameter of the stopper member 28 is slightly larger than the outer diameter of the linear motion output shaft 14a (more specifically, the maximum outer diameter of the portion protruding from the housing 17). When the linear motion output shaft 14a moves in a direction approaching the housing 17 (leftward in FIGS. 3 and 4), the washer 28b of the stopper member 28 finally has an end surface on the nut member 20 (the end surface opposite to the output shaft 16a). ). And this contact | abutting restrict | limits the further movement of the linear motion output shaft 14a. Moreover, the impact at the time of contact is relieved by the elastic deformation of the annular buffer member 28c. Further, by disposing the washer 28b on the contact side of the annular cushioning member 28c, the annular cushioning member 28c is prevented from being engaged with the nut member 20 or the like and becoming inoperable. In the following description, the movement of the linear motion output shaft 14a in the direction in which the stopper member 28 approaches the housing 17 is defined as the forward movement of the linear motion output shaft 14a, and the movement of the linear motion output shaft 14a in the direction opposite thereto is straightened. This is called retraction of the dynamic output shaft 14a.

  Here, when the stopper member 28 comes into contact with the end surface of the nut member 20 in a state where a rotational driving force (rotational driving force in a direction in which the linear motion output shaft 14 a is advanced) is applied from the hollow electric motor 16 to the nut member 20. A rotational driving force acts on the stopper member 28 from the nut member 20. In this case, if this rotational driving force is a rotational driving force in the direction of loosening the screw tightening of the nut 28a of the stopper member 28 with respect to the male screw portion 14ab, the screw tightening of the nut 28a may be loosened. . For this reason, in this embodiment, the direction of the rotational driving force that acts on the stopper member 28 from the nut member 20 when the stopper member 28 abuts on the end surface of the nut member 20 by the advancement of the linear output shaft 14a is determined by the stopper member 28. The rotation direction of the screw tightening of the nut 28a and the rotation direction of the nut main body 20 when the linear motion output shaft 14a moves forward are set so that the nut 28a is tightened. For example, when the threading direction of the male screw part 14ab and the nut 28a is set so that the screwing of the nut 28a with respect to the male screw part 14ab is performed by rotating the nut 28a clockwise, the ball screw By rotating the nut member 20 of the mechanism clockwise, the linear motion output shaft 14a and the nut are moved so that the linear motion output shaft 14a moves forward (the nut member 20 moves backward relative to the linear motion output shaft 14a). The threading direction of the member 20 is set. Thereby, when the stopper member 28 comes into contact with the end surface of the tubular member 20b by the advancement of the linear motion output shaft 14a, the rotational driving force in the direction of loosening the screw tightening of the nut 28a does not act on the stopper member 28. It has become.

  The detailed structure of the linear motion actuator 14 has been described above. The linear motion actuator 14 is entirely accommodated in the upper link member 5. Therefore, it is preferable that the outer housing of the upper link member 5 is made of metal and the noise source including the hollow electric motor 16 is shielded because leakage of noise to the outside can be suppressed. Further, since the linear motion actuator 14 does not jump out of the outer housing of the upper link member 5, the user can easily attach and detach the walking assist device A without being caught.

  The power transmission mechanism 15 of each drive mechanism 9 will be described with reference to FIG.

  The power transmission mechanism 15 includes a crank arm 29 provided on the lower link member 7 coaxially with the joint shaft of the third joint 8 (axial center of the support shaft 8a), the crank arm 29 and the linear motion output shaft 14a. Between the linear motion output shaft 14a and the connecting rod 30 extending coaxially. One end of the connecting rod 30 in the longitudinal direction on the side of the linear output shaft 14a has a male screw portion 30a (shown in FIGS. 3 and 4) protruding from the end face of the connecting rod 30 as the linear output shaft. It is fixed to the linear output shaft 14a by being screwed to 14a (see FIGS. 3 and 4). Further, the other end of the connecting rod 30 is pivotally attached to a pivot portion 29 a at the end of the crank arm 29. Although not shown in detail, the connecting rod 30 is pivotally attached to the pivot portion 29a of the crank arm 29 via a spherical joint. A plastic spring washer is interposed between the connecting rod 30 and the crank arm 29 so as to absorb the backlash of the spherical joint.

  The details of the power transmission mechanism 15 have been described above.

  In the power transmission mechanism 15, when the translational force in the axial direction is generated on the linear motion output shaft 14 a of the linear motion actuator 14 by operating the hollow electric motor 16, the translational force causes the connecting rod 30 to move. It acts on the pivotal support part 29a of the crank arm 29. For example, a translational force F acts as shown by an arrow F in FIG. At this time, since the pivotal support portion 29a is eccentric with respect to the joint axis of the third joint 8, the translational force F acting on the pivotal support portion 29a (more specifically, of the translational force F, the joint of the third joint 8). The moment (torque) around the joint axis of the third joint 8 acts on the lower link member 7 by the component in the direction perpendicular to the straight line connecting the shaft (the axis of the support shaft 8a) and the pivot 29a. The lower link member 7 is rotationally driven with respect to the upper link member 5 by this torque, and the leg link 3 is bent and extended at the third joint 8. In this case, in the present embodiment, the pivotal support portion 29a, when viewed in the axial direction of the joint axis of the third joint 8, is connected to the joint axis of the third joint 8 (axial center of the support shaft 8a) and the swinging portion. It is arranged above the straight line connecting the moving shaft 19. For this reason, by generating a translational force in the backward direction (translational force that becomes a tensile force between the pivotal support portion 29a of the crank arm 29 and the nut member 20) on the linear motion output shaft 14a of the linear motion actuator 14, The third joint 8 is driven in the extending direction of the leg link 3. Further, in this case, the axis of the swing shafts 19, 19 for swinging the housing 17 in accordance with the bending / extending operation of the leg link 3 is the axis of the nut member 20 inside the nut member 20 of the ball screw mechanism. Therefore, it is possible to suppress the bending force from acting on the linear motion output shaft 14a inside the nut member 20 as much as possible. For this reason, the movement of the linear output shaft 14a in the axial direction according to the rotational drive of the nut member 20 can be performed stably and smoothly.

  The above is the mechanical main configuration of the walking assist device A of the present embodiment. In addition, although illustration is abbreviate | omitted, in order to perform driving | operation control of the hollow electric motor 16 of the linear motion actuator 14, the control apparatus etc. which include a microcomputer etc. are mounted in the suitable place of the walking assistance apparatus A. For example, the control device is mounted inside the basic frame 1 b of the seating unit 1. Furthermore, the walking assist device A is also equipped with a sensor for detecting the pedaling force of the user and a sensor for detecting the bending angle of each leg link 3, and the output of these sensors is used for motion control of the hollow electric motor 16. Used.

  In the walking assist device A, each leg in a grounded state is configured so that a load (upward translational force) that supports a part of the weight of the user is constantly applied to the user from the seating portion 1 when the user walks. The third joint 8 of the link 3 is driven. More specifically, a translational force having a predetermined value (for example, a translational force that supports a predetermined ratio (for example, 20%) of the user's weight) is set as a target load to be applied to the user from the seating portion 1, and this target load is generated. Therefore, the required torque of the third joint 8 required for this purpose (the required torque in the extending direction of the leg link 3) is determined by calculation processing of a control device (not shown). Then, the output torque of the electric motor 16 is controlled so that this required torque acts on the third joint 8. Thereby, the target load acts on the user from the seating portion 1, and the burden on the leg of the user is reduced.

  Although the embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to this. For example, in the above-described embodiment, the motor housing 25 that houses the hollow electric motor 16 is disposed so as to be adjacent to the knee-side end portion of the casing 17, but is adjacent to the crotch-side end portion of the casing 17. It is also possible to arrange them.

  Moreover, in the said embodiment, although the load transmission part was comprised by the seat part 1 which has the saddle-shaped seat part 1a, the load transmission part was comprised by the harness-like flexible member with which a user's waist circumference is mounted | worn. Also good. The load transmitting unit preferably includes a portion that contacts the user between the bases of both legs in order to apply an upward translational force to the trunk of the user.

Moreover, in the said embodiment, the 1st joint 4 is comprised in what has the arc-shaped guide rail 11, and the curvature center 4a of the guide rail 11 as a rocking | fluctuation fulcrum of the front-back direction of each leg link 3 is the seating member 1. For example, the upper end portion of the leg link 3 is positioned above the seating portion 1, but the upper end portion of the leg link 3 is laterally moved at the side portion or lower portion of the seating portion 1, for example. The first joint 4 may be configured with a simple joint structure that is pivotally supported by the (left-right direction) axis. Also, in order to assist a user who is inconvenienced by a broken leg or the like, Of the left and right leg links 3 and 3 of the form, only the leg link on the leg side that is inconvenient to the user may be left and the other leg link may be omitted.

The side view which shows schematic structure of the walking assistance apparatus which concerns on one Embodiment of this invention. The figure which fractures | ruptures and shows the upper side link member of the walking assistance apparatus of FIG. FIG. 3 is a cross-sectional view taken along line I I I-I I I in FIG. 2. IV-IV sectional view taken on the line of FIG.

Explanation of symbols

  A ... walking assist device, 1 ... seating member (load transmission part), 2 ... foot mounting part, 3 ... leg link, 4 ... first joint, 4a ... center of curvature of guide rail, 5 ... upper link member, 6 ... Second joint, 7 ... lower link member, 8 ... third joint, 8a ... support shaft, 9 ... drive mechanism, 11 ... guide rail, 12 ... slider, 14 ... linear motion actuator, 14a ... linear motion output shaft (straight shaft) (Dynamic shaft member), 14aa ... screw groove, 15 ... power transmission mechanism, 16 ... hollow electric motor, 16a ... output shaft (inner rotor), 17 ... housing, 18 ... bearing member, 18a ... bearing, 19 ... support shaft, Oscillating shaft, 20 ... nut member (inner collar), 20 ... nut member, 21 ... ball, 22a, 22b ... bearing, 24 ... outer collar, 25 ... motor housing, 26 ... encoder, 27 ... bearing, 29 ... crank door Arm, 29a ... pivot portion, 30 ... connecting rod.

Claims (2)

A load transmitting unit that transmits a load that supports a part of the user's weight to the user's trunk, a foot mounting unit that is mounted on the user's foot, and the foot mounting unit as a load transmitting unit An upper link member that extends from the load transmitting portion via the first joint, and a lower side that extends from the foot mounting portion via the second joint. In the walking auxiliary device comprising a link member, and a third joint that connects the upper link member and the lower link member so as to be able to bend and extend, and further comprising a drive mechanism for driving the third joint,
The drive mechanism is supported by a casing that is swingably connected to the upper link member, and is rotated by a hollow electric motor, and the nut member is connected to the nut member via a ball held by the nut member. A linear motion actuator having a thread groove to be screwed on an outer peripheral surface, and a linear motion output shaft that is inserted through a through hole formed in a hollow inner rotor of the hollow electric motor, and a third link on the lower link member A crank arm fixed coaxially with the joint shaft and pivotally attached to one end of the linear motion output shaft; and a translational force output from the linear motion output shaft of the linear motion actuator via the crank arm. It is configured to convert to rotational driving force of 3 joints ,
The walking assist device , wherein the linear motion actuator is accommodated in the upper link member .   The walking assist device according to claim 1, wherein the nut member and the hollow inner rotor are fixedly connected to each other.

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