JP2009269156A - Torsion string actuator and actuator unit for artificial limb therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten work time for preventing wire for connecting an object to be driven with a slide member of a torsion string actuator from becoming loose and attaining constant tension. <P>SOLUTION: The torsion string actuator includes a torsion string 1 in such a structure that two strings are twisted with each other, a driving mechanism part 20 connected to a base end side of the torsion string 1, the slide member 32 connected to a top end side of the torsion string 1, and the wire 5 connected between the top end side and the object to be driven. The length of the torsion string 1 changes corresponding to operation of the driving mechanism part 20 and the slide member 32 displaces in a longitudinal direction of the torsion string 1, thus transmitting displacement to the object to be driven through the wire 5. Adjustment means 7 for adjusting the degree of tension of the wire 5 is provided at a connection part between the slide member 32 and the wire 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a twisted string actuator having a structure in which two strings are twisted together, a twisted string actuator using a motor, and an actuator unit for a prosthesis using the same.

  2. Description of the Related Art Conventionally, as a type of actuator used for a robot hand, an electric prosthesis, or the like, for example, an actuator using a wire and a motor (hereinafter referred to as a wire-type actuator) as described in Patent Document 1 or 2 is known. FIG. 13 shows a basic structure of a conventional wire actuator.

  In the wire actuator shown in FIG. 13, a rotating body 102 such as a pulley is connected to a rotating shaft 101a of a motor 101 via a speed reducer. Alternatively, the rotating body 102 is directly connected to the rotating shaft 101a of the motor 101 with a built-in reducer. One wire 103, 104 is connected to each of two locations in the radial direction of the rotating body 102, and the other end of each wire 103, 104 is connected to the finger joint 105.

  When the rotating shaft 101a of the motor 101 rotates, the rotating body 102 rotates slowly, and the two wires 103 and 104 are driven in opposite directions. That is, one is pulled and the other is loosened. As a result, the finger joint 105 is driven to rotate about the axis AX.

  When using wire actuators such as those described above for robot hands or electric prostheses with many joints, it is necessary to use a small motor or ultra-small motor as the motor required for each joint, and to reduce the weight of the entire device. is there. Moreover, in order to ensure a certain level of gripping force required for electric prostheses, robot hands, etc., a certain amount of output torque is required for the drive system including the motor and the speed reducer.

  Even with a small motor, it is possible to obtain a large torque by using a speed reducer, but the speed reducer itself increases the weight of the device, so that, for example, the prosthetic limb and the tip of the robot hand become heavy. Problems arise. Further, it may be difficult to realize a small and lightweight electric prosthesis or a robot hand in order to secure a space for incorporating a reduction gear.

  In addition, when using a gear-type speed reducer that incorporates multiple stages of reduction gears, in addition to the problem of increased weight and space, noise generated at the meshing portion between the gears when the gear rotates is large. There is also a problem.

  As a wire actuator capable of solving such a problem, the present applicant has previously filed a patent application for an invention relating to a twisted string actuator. In this twisted string actuator, the base end side of a twisted string having a structure in which two strings are twisted together is connected to a drive mechanism section including a motor, and the distal end side of the twisted string is connected to a driving object via a slide member and a wire. Has been. When the motor of the drive mechanism section rotates, the twist of the two strings constituting the twisted string is strengthened or loosened, so that the length of the twisted string is expanded and contracted. As a result, the slide member is displaced in the longitudinal direction of the twisted string, and this displacement is transmitted to the driven object through the wire.

  When an electric prosthesis, a robot hand, or the like is formed using a plurality of sets of the twisted string actuators as described above, at least one joint is required for each finger. One joint is required. For example, when three joints are provided on the thumb, two joints are provided on the other four fingers, and two joints are provided on the wrist, a total of 13 joints are required. Therefore, 13 sets of twisted string actuators are required.

  In order to drive one joint in both directions, it is desirable to use two (a pair) of twisted strings that expand and contract in opposite directions. Therefore, a preferable configuration of a set of twisted string actuators for driving each joint includes, for example, one drive mechanism unit, two twisted strings connected to the two rotation output shafts, Two slide members connected to the distal end side of the twisted string, and two wires connecting each slide member and the joint are provided.

When the motor of the drive mechanism unit rotates, it is driven so that one of the pair of twisted strings extends and the other contracts. As a result, the pair of slide members are displaced in the opposite directions along the longitudinal direction of the twisted string, and the joint connected to the tips of the pair of wires is driven so as to rotate around the fulcrum.
Japanese Patent Laid-Open No. 06-008178 Japanese Patent Application Laid-Open No. 07-096485

  In the assembly process of the twisted string actuator as described above, when the wire is manually stretched between the finger joint to be driven and the slide member, the wire may be loosened at the fixed stage. . There is also a problem that the tension of the wire varies depending on the operator. If the wire connection / fixing operation is performed in a state where there is no such looseness or variation in tension, there is a disadvantage that the time required for the operation becomes long.

  If the pair of wires connected to the pair of twisted strings via the slide member is loose or the tension is greatly different, the initial state of the finger joint becomes difficult to be determined. Alternatively, the twisting degree (stretching degree) of the pair of twisted strings corresponding to the initial state of the finger joints changes, so that the operation characteristics regarding the state of the finger joints and the twisted degree of the twisted string actuators change, and stable operation is achieved. There is a risk of damage. Further, it is desirable that the tension of the wire is constant and does not become loose between a plurality of sets of twisted string actuators used for a plurality of finger joints.

  In view of the above-described conventional problems, the present invention can prevent loosening of a wire connecting a sliding member of a twisted string actuator and a driving object, and can perform a work for making the tension constant in a short time. The purpose is to do.

  Another object of the present invention is to facilitate connection, removal, and reconnection of a twisted string and a rotary output shaft in a prosthetic limb actuator unit using a plurality of sets of twisted string actuators.

  The twisted string actuator according to the present invention includes a twisted string having a structure in which two strings are twisted together, a drive mechanism unit having a rotation output shaft connected to a proximal end side of the twisted string, and a distal end side of the twisted string And a wire connected between the slide member and the drive object, and a rotation output shaft of the drive mechanism portion is connected to the slide member. When it rotates, the length of the twisted string changes due to the strength change of the two strings constituting the twisted string, and as a result, the slide member is displaced in the longitudinal direction of the twisted string, and the displacement is the wire A twisted string actuator that is transmitted to the driven object through an adjustment means that adjusts the tension of the wire at a connecting portion between the slide member and the wire. It is characterized in that is. (Claim 1).

  According to such a configuration, after the wire is connected between the slide member and the drive target, the loosening of the wire is eliminated using the adjusting means for adjusting the tension of the wire, and the tension is adjusted to a predetermined tension. It becomes possible. For example, it is possible to easily adjust in a short time so that the tension of the pair of wires connected to the finger joint is substantially equal and is not loosened. As a result, the twist degree (stretching degree) of the pair of twisted strings corresponding to the initial state of the finger joint can be made constant, and stable operation of the twisted string actuator can be ensured.

  As a specific form, the adjusting means preferably includes a winding shaft around which the end of the wire is wound, and a knob portion for manually rotating the winding shaft (claim 2).

  As a more preferred form, the apparatus further comprises an adjustment amount grasping means that makes it possible to grasp the adjustment amount of the tension of the wire by the adjustment means by visually checking the rotation amount of the winding shaft ( Claim 3).

  A prosthetic limb actuator unit according to the present invention is a prosthetic limb actuator unit that drives a plurality of finger joints to be driven using a plurality of sets of twisted string actuators configured as described above, wherein the drive mechanism unit, A plurality of sets of actuator parts including a twisted string, the slide member, and the adjusting means are arranged substantially in parallel, and these are fixed to a fixing base constituting a prosthesis (Claim 4). According to such a configuration, the tension of the pair of wires connected to each finger joint is made substantially equal, and the tension of the wires between the plurality of sets of twisted string actuators connected to the plurality of finger joints is unified. Can be easily realized.

  In a preferred embodiment of the prosthetic limb actuator unit of the present invention, a recess in which the whole or a part of the drive mechanism is embedded is formed on the surface of the fixed base, and the rotation output shaft of the drive mechanism and the twist Connection with the base end side of the string is made via a string fixing member that is detachable from the rotary output shaft. According to such a configuration, the prosthetic limb actuator unit can be configured to be thin, and the twisted string and the rotation output shaft when the prosthetic limb actuator unit is assembled can be easily connected. In addition, for example, when the drive mechanism unit is replaced, the work of temporarily disconnecting and reconnecting the twisted string and the drive mechanism unit is simplified.

  As described above, according to the present invention, after the wire is connected between the slide member and the drive target, the loosening of the wire is eliminated by using the adjusting means for adjusting the tension of the wire, and the predetermined tension is obtained. Therefore, the wire connection and adjustment work can be performed in a shorter time than in the prior art. In addition, it is possible to easily connect, remove, and reconnect the twisted string and the rotation output shaft when assembling the prosthetic limb actuator unit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, although the positional relationship and direction of each member may be described in the upper, lower, left and right directions, it means the positional relationship and direction in the drawing to the last, and it means the positional relationship and direction when actually used or assembled. is not.

  FIG. 1 is a schematic diagram showing the concept of the twisted string actuator of the present invention. The twisted string actuator shown in FIG. 1 is configured using a twisted string 1 and a motor 2 having a structure in which two strings 11 and 12 are loosely twisted together. FIG. 1A schematically shows a state in which the twisting of the two cords 11 and 12 is loosened to form two parallel cords, and FIG. 12 schematically shows a state in which 12 are twisted together. One end side of the twisted string 1, that is, the two strings 11, 12 is connected (fixed) to the driving object OB, and the other end side is connected (fixed) to the rotating shaft 21 of the motor 2.

  The length of the twisted cord 1 in the state shown in FIG. 1 (a) is L, and the rotating shaft 21 of the motor 2 rotates from this state to constitute the twisted cord 1 as shown in FIG. 1 (b). When the two cords 11 and 12 are twisted together, the length of the twisted cord 1 is L−ΔL. That is, when the two cords 11 and 12 are twisted together, the length of the twisted cord 1 is shortened by ΔL. As a result, the driving force F in the direction (right direction) attracted to the motor 2 by the tension of the twisted string 1 acts on the driving object OB. Therefore, the twisted string 1 has a function of converting the rotational motion in the twisted direction (the rotational force of the motor 2) into the linear motion (tension) in the lengthwise direction.

  When the rotating shaft 21 of the motor 2 rotates in the direction opposite to the above from the state of FIG. 1B, the twist of the two cords 11 and 12 constituting the twisted cord 1 is loosened. At this time, although not shown in FIG. 1, if it is assumed that the object OB is urged leftward by an urging means such as a tension spring, the object OB moves away from the motor 2 by the urging force (left Direction) and the length of the twisted string 1 is extended. It can be seen that the length of the twisted cord 1 is the longest value (L) in the state of FIG. 1A in which the twisting of the two cords 11 and 12 is loosened to form two parallel cords. .

  Therefore, according to the above-described twisted string actuator using the twisted string 1 and the motor 2 having a structure in which the two strings 11 and 12 are loosely twisted together, the twisted string according to the rotation direction of the rotating shaft 21 of the motor 2. The length of the twisted cord 1 is shortened or extended by strengthening or loosening the twist of the two cords 11 and 12 constituting 1, and as a result, the drive object OB is kept within a predetermined range. It is possible to drive.

  Since the twisted string 1 functions as power transmission means including a speed reduction mechanism, a speed reducer using a multi-stage gear or the like is not required, and can greatly contribute to reduction in size and weight of the entire apparatus. In addition, there is no noise generated by a reduction gear using a multistage gear or the like, and a silent actuator can be realized. In general, a twisted string is less expensive than a speed reducer using a multistage gear or the like, so that the cost of the actuator can be reduced.

  Further, since there is a certain degree of flexibility and elasticity between the rotational movement in the twist direction and the linear movement in the length direction of the twisted string 1, it is not necessary to use an elastic biasing means such as a spring or an air cylinder. However, it is possible to realize a so-called soft actuator. Thereby, for example, a compliance function like a human hand can be easily realized.

  FIG. 2 is a schematic diagram illustrating an application example in which a finger joint is driven using a twisted string actuator. In this schematic diagram, a finger joint FJ that can rotate about an axis AX corresponds to a drive object. As shown in FIG. 2, in order to regulate the driving direction and driving range of the finger joint FJ as a driving object, a slide member 32 that is movable within a predetermined range along the slide guide 31 is provided. It is connected to the tip side. The slide member 32 is allowed only to slide in the longitudinal direction of the twisted string 1. A wire 5 is stretched between the slide member 32 and the finger joint FJ.

  As shown in FIG. 2, two sets of twisted string actuators including the twisted string 1, the motor 2, the slide member 32, and the wire 5 are provided, and at two locations P1 and P2 facing each other across the axis AX of the finger joint FJ, The distal ends of the wires 5 of the two sets of twisted string actuators are connected to each other.

  In the configuration of FIG. 2, the driving direction and driving range of the finger joint FJ that is the driving object can be easily regulated by the slide guide 31 and the slide member 32. In addition, since design flexibility regarding the distance and direction between the motor 2 and the finger joint FJ can be secured, it becomes easy to cope with the limitation of the space where the actuator is mounted, and the effective use of the space is facilitated. It becomes possible.

  The twisted strings 1 of the two sets of twisted string actuators are driven in opposite directions. For example, as shown in FIG. 2, the upper twisted string 1 is driven in the direction of shortening, and the lower twisted string 1 is driven in the extending direction. Thereby, the finger joint FJ can be rotationally driven around the axis AX. In the configuration shown in FIG. 2, two motors 2 are used to individually drive the twisted strings 1 of the two sets of twisted string actuators. In this configuration, it is necessary to control driving of the two motors 2 in synchronization. It is also preferable to provide an interlock circuit that prevents only one motor 2 from operating. In order to simplify such control and circuit, as will be described later, the twisted cords 1 of the two sets of twisted cord actuators may be driven simultaneously using one motor.

  FIG. 3 is a schematic diagram showing an application example of the twisted string actuator shown in FIG. 2 to a plurality of finger joints. A state in which two finger joints FJ1 and FJ2 are pivotally connected by an axis AX1 is shown. The finger joint FJ1 can rotate about the axis AX1, and the finger joint FJ2 can rotate about the axis AX2. Although omitted in FIG. 3, the finger joint FJ2 is also provided with two sets of twisted string actuators including the twisted string 1 and the slide member 32 and facing each other across the axis AX2 in the same manner as the finger joint FJ1. In addition, one end side of the twisted string 1 of the two sets of twisted string actuators is connected to each other via the slide member 32. In this example, two twisted string actuators are used for one joint, and in the case of n joints, 2n twisted string actuators are used.

  FIG. 4 is a schematic diagram showing a configuration example in which two twisted strings are simultaneously driven by one motor. This configuration example is configured to drive the twisted cords 1 of two pairs of twisted cord actuators simultaneously using one motor in the configuration shown in FIG. 2 or FIG. 3. That is, the base end side (motor side) of the twisted string 1 of the two sets of twisted string actuators is connected to two different rotation output shafts 41 and 42 of the power transmission mechanism 4 connected to the rotation shaft 21 of the motor 2. Has been. When the rotating shaft 21 of the motor 2 rotates, the upper first rotating output shaft 41 rotates in a direction to increase the twist of the twisted string 1 connected thereto, and the lower second rotating output shaft 42 is connected thereto. It is comprised so that it may rotate in the direction which loosens the twist of the twisted string 1.

  In this configuration, a twisted cord actuator including two pairs of twisted cords 1 is used for one finger joint FJ1, and the twisted cords 1 are simultaneously driven by one motor 2, so that the two motors individually Compared with the case of driving the motor, the drive control is simplified. In addition, the finger joint FJ1 can be driven quickly.

  In the configuration shown in FIG. 4, as the power transmission mechanism 4, a speed reduction / reversal mechanism using one pinion gear 43 and two flat gears 44 and 45 is used. The pinion gear 43 is fixed to the rotating shaft 21 of the motor 2, the upper flat gear 44 is fixed to the first rotating output shaft 41 to which the upper twisted string 1 is connected, and the lower flat gear 45 is It is fixed to the second rotation output shaft 42 to which the twisted string 1 is connected. Since the upper flat gear 44 and the lower flat gear 45 rotate in the same direction (both directions opposite to the pinion gear 43), the twist directions of the twist strings 1 of the two twist string actuators are opposite to each other. There is a need.

  That is, when the rotating shaft 21 of the motor 2 rotates, the first rotating output shaft 41 and the second rotating output shaft 42 rotate in the same direction (both opposite to the rotating shaft 21 of the motor 2). Since the twist directions of 1 are opposite to each other, for example, as shown in FIG. 4, the upper twist string 1 is driven in the direction of increasing the twist (the direction in which the length is shortened), and the lower twist string 1 is Driven in the direction of loosening the twist (the direction in which the length extends).

  By changing the number and combination of the gears constituting the power transmission mechanism 4, the power transmission mechanism 4 is configured so that the rotation directions of the two rotation output shafts 41 and 42 are opposite to each other, and two twists in the upper and lower directions You may make it the twist direction of the string 1 become the mutually same direction. In short, when the rotating shaft 21 of the motor 2 rotates, one of the first rotating output shaft 41 and the second rotating output shaft 42 rotates in the direction of increasing the twist of the twisted string 1, and the other loosens the twist of the twisted string. What is necessary is just to comprise the power transmission mechanism 4 and the twisted string 1 so that it may rotate to a direction. However, it is desirable to configure the power transmission mechanism 4 so that the output torques of the first rotation output shaft 41 and the second rotation output shaft 42 are equal to each other, or so that both are balanced.

  Further, in order to avoid the generation of noise at the meshing portion between the gears, the power transmission mechanism 4 is configured by using a plurality of rollers or rollers and belts that transmit power by the frictional force of the contact surface instead of the gears. May be. It is also desirable to reduce noise generated from the motor 2 by using a DC brushless motor as the motor 2.

  FIG. 5 is a cross-sectional view showing structures of the motor 2 and the gear box 4 of the twisted string actuator according to the embodiment of the present invention. The gear box 4 corresponds to the power transmission mechanism 4 in the above description. The gear box 4 and the motor 2 are integrally coupled to constitute a drive mechanism unit 20. The gear box 4 has a box shape surrounded by a base end side plate 46, a front end side plate 47, and a side plate 48, and the above-described pinion gear 43, flat gears 44, 45, and the like are accommodated in the internal space thereof. Yes.

  A through hole through which the rotation shaft 21 of the motor 2 and the pinion gear 43 fixed thereto is inserted is formed in the central portion of the base end side plate 46 of the gear box 4, and the outer side surface (lower surface) around it is formed. A stepped recess for receiving the case tip of the motor 2 is formed. The stepped recess of the base end plate 46 and the case tip of the motor 2 are fixed to each other by means such as fitting, bonding, and screwing.

  Further, on the inner side surface (upper surface) of the base end side plate 46, two fixed shaft members 49 for rotatably supporting the flat gears 44 and 45 are provided on both sides at a predetermined distance from the central through hole. It is installed. Cylindrical portions 441 and 451 are integrally provided above and below the spur gears 44 and 45, and sleeve bearings that are externally fitted to the fixed shaft member 49 are provided at the center thereof. Thereby, the spur gears 44 and 45 can be supported by the fixed shaft member 49 and can idle. Further, the spur gears 44 and 45 are screwed into the pinion gear 43 and are driven to rotate as the rotating shaft 21 of the motor 2 rotates.

  Rotation output shafts 41 and 42 are integrally provided so as to protrude upward (front end side) from the upper central portion of the spur gears 44 and 45, and the rotation output shaft is provided on the front end side plate 47 of the gear box 4. Two through holes through which 41 and 42 are inserted are formed. The rotation output shaft 41 (42), the cylindrical portion 441 (451), and the spur gear 44 (45) are formed as individual members, which may be integrally coupled, or all or one of them. The part (two of the three) may be formed as an integral member from the beginning.

  Further, an annular groove is formed around the through hole through which the rotation output shafts 41 and 42 are inserted on the inner side surface (lower surface) of the tip side plate 47, and an annular ring made of an oil-containing sintered alloy is formed in this groove. The member 51 is fitted and fixed by means such as adhesion. In addition, annular sliding surfaces 442 and 452 that are slidable in contact with the annular member 51 are formed on the distal ends of the cylindrical portions 441 and 451.

  A portion enclosed by a two-dot chain line rectangle in the upper part of FIG. 5 is a plan view of the annular member 51 as viewed from the axial direction. As can be seen from this plan view, twelve hemispherical protrusions 511 are provided on the annular surface of the annular member 51 opposite to the annular sliding surfaces 442 and 452 on the rotation side, spaced apart in the circumferential direction. The tip of the hemispherical protrusion 511 is configured to contact the annular sliding surfaces 442 and 452.

  The annular member 51 functions as a thrust bearing that regulates and holds the movement of the rotation output shafts 41 and 42 in the axial direction. That is, when the twist of the twisted string connected to the tip of the rotation output shafts 41 and 42 is strengthened and the length of the twisted string is shortened, the rotation output shaft 41 acts as a reaction of the driving force that draws the drive object. , 42 is pulled in the direction of the driven object (hereinafter referred to as thrust force). The thrust force is received when the annular sliding surfaces 442 and 452 on the distal end side of the cylindrical portions 441 and 451 come into contact with the hemispherical projection 511 (the distal end portion) of the annular member 51.

  Since the annular member 51 is made of an oil-impregnated sintered alloy and realizes smooth sliding with the annular sliding surfaces 442 and 452 on the rotation side, even if the thrust force increases, the rotational drive output is unlikely to decrease. Moreover, a space-saving and inexpensive thrust bearing can be realized as compared with the case where a ball bearing is used. Thereby, a small and inexpensive twisted string actuator can be realized.

  In addition, since the tip portions of the twelve hemispherical protrusions 511 provided on the annular member 51 are in contact with the annular sliding surfaces 442 and 452 on the rotation side, the entire surface of the annular member 51 is annularly slid. Since the area of the contact surface (sliding surface) is smaller than when contacting the surfaces 442 and 452, output loss due to sliding friction on the contact surface is reduced. As a result, an inexpensive twisted string actuator can be realized in which the rotational drive output is less likely to decrease even when the thrust force increases. It is not necessary to limit the number of hemispherical protrusions 511 provided on the annular member 51 to twelve, and if it is at least three, stable operation as a thrust bearing can be obtained.

  Prepare a set of twisted string actuators composed of the drive mechanism unit 20, the pair of twisted strings 1, the slide member 32, and the wires 5 as described above as many as the number of finger joints to be driven, and arrange them in an appropriate arrangement. Thus, an actuator unit for artificial limbs can be configured. The prosthetic limb actuator unit of the present invention is applicable to a robot hand or the like in addition to a prosthetic limb. For example, in a prosthesis, at least one joint is required for each finger, and two joints are required for each finger to enable fine movement. If there are 3 joints on the thumb, 2 joints on the other 4 fingers, and 2 joints on the wrist, a total of 13 joints are required. Therefore, 13 sets of twisted string actuators are required.

  In order to make the entire prosthetic limb actuator unit compact, it is necessary to efficiently arrange 13 sets of twisted string actuators, particularly 13 drive mechanism sections 20. For example, as shown in the schematic diagram of FIG. 6, the 13 drive mechanism units 20, the pair of twisted strings 1, and the slide member 32 can be arranged in an annular shape. In FIG. 6, a pair of first and second frame members 61 and 62 having an annular shape are arranged so as to face each other at a predetermined interval, and both are connected and fixed by three rod-like connecting members 63. . Thirteen drive mechanism sections 20 are arranged and fixed on the base end surface of the first frame member 61 along the circumferential direction. As described with reference to FIGS. 4 and 5, each drive mechanism unit 20 includes the motor 2 and the gear box (power transmission mechanism) 4 and has two rotation output shafts 41 and 42.

  Although not shown in FIG. 6, the two rotation output shafts 41 and 42 protrude from the inner surface of the first frame member 61, and the proximal end side of the twisted string 1 is connected to the respective rotation output shafts 41 and 42. ing. In FIG. 6, a twisted string 1 (see FIG. 4) composed of two strings 11 and 12 is drawn by a single solid line. Further, the pair of twisted cords 1 shown in FIG. 4 constitutes a set of twisted cord actuators.

  In FIG. 6, 13 sets of slide members 32 are arranged on the second frame member 62 along the circumferential direction. As shown in FIG. 4, two slide members 32 are provided in one set of twisted string actuators, and are connected to the two twisted strings 1, respectively. In FIG. 6, a pair of two slide members 32 is drawn in a rectangular shape. Each slide member 32 is connected to the distal end side of each twisted string 1, and only sliding movement in the longitudinal direction of the twisted string 1 is allowed. That is, the slide member 32 is fitted into a square hole formed so as to penetrate the second frame member 62, and displacement and rotation (rotation) in the circumferential direction and the radial direction of the second frame member 62 are restricted. Only displacement in the axial direction (longitudinal direction of the twisted string 1) is allowed.

  Thereby, when the twisted string 1 expands and contracts as described above with the operation of the drive mechanism unit 20, the slide member 32 can be displaced in the longitudinal direction of the twisted string 1. Although not shown in FIG. 6, as shown in FIG. 4, the slide member 32 is connected to the finger joint to be driven via the wire 5. The finger joint can be moved by displacing in the longitudinal direction.

  According to this embodiment, for example, a plurality of sets of twisted string actuators can be efficiently arranged around the arm of a prosthetic limb to effectively use the space. It can arrange | position so that the arm part or leg part of a artificial limb or the arm part of a robot hand may pass through the cylindrical space which connects the circular opening part of the center of a pair of frame members 61 and 62. FIG.

  As another embodiment, as shown in FIG. 7, the drive mechanism 20 and the slide guide 31 are fixed on a plate-like fixing base 6, and in addition to these, a pair of twisted strings 1, a slide member 32, and a wire, respectively. A pair of twisted string actuators including 5 may be configured. For a prosthetic limb for driving a plurality of finger joints, a plurality of such fixing bases 6 are connected in the width direction and arranged in a substantially cylindrical shape so as to be wound around the arm portion or leg portion of the prosthesis or the arm portion of the robot hand An actuator unit is configured.

  In the assembly process of the twisted string actuator as described above or the prosthetic limb actuator unit using the twisted string actuator, when connecting the finger joint to be driven and the slide member 32 so as to stretch the wire 5 manually, The wire 5 may be loosened when the wire 5 is fixed. That is, as shown in FIG. 7, when the tip of the wire 5 is fixed to the hole 32 a formed on the tip side of the slide member 32, the wire 5 is loosened between the finger joint and the slide member 32 (sagging). ) May occur. That is, the tension of the wire 5 varies depending on the operator. Conversely, if it is attempted to connect and fix the wire 5 in such a state that there is no such looseness and the tension is uniform, the time required for the operation becomes long.

  Therefore, as shown in FIG. 8, an adjustment mechanism (adjustment means) 7 that adjusts the length of the connecting portion between the slide member 32 and the wire 5 by winding the proximal end side of the wire 5 is provided. In FIG. 8, the proximal end side of the wire 5 is connected to the wire (or string) 5 a protruding from the proximal end side of the adjustment mechanism 7 at the proximal end side of the wire 5. If the wire 5 has flexibility (softness) that can be wound, the base end side of the wire 5 may be directly connected to the adjusting mechanism 7 and wound. In either case, after the wire 5 is connected between the finger joint and the slide member 32, the tension of the wire 5 can be adjusted using the adjusting mechanism 7.

  A configuration example of the adjustment mechanism 7 is shown in an exploded perspective view in FIG. The adjustment mechanism 7 shown in FIG. 9 includes an upper case 71, a lower case 72, a winding shaft 73, a rotation nut 74, a knob portion 75, and the like. The upper case 71 and the lower case 72 are made of metal such as resin or aluminum, and both have a shape in which low walls 711 and 721 are formed on both sides of a rectangular plate. The upper case 71 and the lower case 72 are joined together by means such as adhesion and welding so that the front end surfaces of the respective walls 711 and 721 are brought into contact with each other. It is good also as a structure which couple | bonds both by means, such as a screw stop or a fitting.

  The upper case 71 and the lower case 72 (hereinafter referred to as cases 71 and 72) coupled to each other have a space inside, and the distal end side of the slide member 32 is located on the base end side (starboard side in FIG. 9). An opening PO to be inserted is formed. A through hole 712 through which a bolt 76 for fixing the slide member 32 to the cases 71 and 72 is inserted is formed near the base end side of the upper surface of the upper case 71. A screw hole 722 having a female screw that matches the male screw is formed. As shown by a broken line in FIG. 9, the bolt 76 is screwed into the screw hole 722 of the lower case 72 through the through hole 712 of the upper case 71 and the hole 32 a of the slide member 32, whereby the slide member 32 and the cases 71, 72. (Ie, the adjusting mechanism 7) is fixed (connected) as shown in FIG.

  An opening DO into which the wire 5a to be wound is inserted is formed on the distal ends of the cases 71 and 72. Further, a through hole 713 through which the upper portion of the take-up shaft 73 is inserted is formed near the front end side of the upper surface of the upper case 71, and a through hole 723 through which the lower portion of the take-up shaft 73 is inserted at a corresponding portion of the lower case 72. Is formed. Further, a male screw 731 is cut on the upper portion of the winding shaft 73, and a detent nut 74 that is screwed to the male screw 731 is screwed into the winding shaft 73 from the upper surface side of the upper case 71.

  The locking nut 74 fixes the winding shaft 73 so as to sandwich the peripheral portion of the through hole 713 of the upper case 71 with the flange portion 732 formed below the male screw 731 of the winding shaft 73 (rotation). Has a function (anti-rotation function). In addition, it is preferable to build up the peripheral part (annular part) of the through hole 713 of the upper case 71. Furthermore, by providing unevenness on the contact surface between the annular portion and the flange portion 732 of the winding shaft 73, the above-described anti-rotation function can be ensured.

  When the winding shaft 73 is rotated to wind the wire 5a, the locking nut 74 is loosened, and the locking nut 74 is tightened in a state where the wire 5 is adjusted to an appropriate tension. Will be fixed. A knob portion 75 for facilitating the rotation operation is fixed to the upper end of the winding shaft 73 by means such as screwing, fitting, and adhesion. In order to ensure the fixing of the knob portion 75 and the winding shaft 73 (preventing idling), the cross-sectional shape of the upper end portion of the winding shaft 73 is an irregular shape that functions to prevent rotation, and the recess that fits into the knob is pinched. You may make it form in the lower surface of the part 75. FIG.

  As a modification of the present embodiment, as shown in FIG. 10, a hexagonal recess 734 for a hexagonal wrench may be provided on the upper end surface of the winding shaft 73. In this case, when adjusting the tension of the wire 5, a predetermined hexagon wrench is fitted into the hexagonal recess 734 to rotate the winding shaft 73, and then the rotation prevention nut 74 is tightened to fix the winding shaft 73. be able to. Therefore, the knob portion 75 can be omitted.

  Further, the hook 733 provided below the flange portion 732 of the winding shaft 73 is used for hooking the proximal end side when the wire 5a is wound around the winding shaft 73. In the illustrated example, the wire (or string) 5a is wound around the winding shaft 73, and the proximal end side of the wire 5 is connected to the distal end portion thereof (see FIG. 8), but the proximal end side of the wire 5 is wound up. It is good also as a structure wound around the shaft 73 directly. In that case, for example, a small ring is formed on the proximal end side of the wire 5, and the rotation position of the winding shaft 73 is such that the hook 733 of the winding shaft 73 can be seen from the opening DO on the distal end side of the cases 71 and 72. Is adjusted, and the winding shaft 73 is rotated after the ring on the proximal end side of the wire 5 is hooked on the hook 733 so that the proximal end side of the wire 5 is wound.

  As another modification of the present embodiment, as shown in FIG. 11, a scale 714 may be provided on the upper case 71 around the rotation nut 74. The scale 714 is an adjustment amount grasping means that makes it possible to grasp the winding amount of the wire 5a (that is, the adjustment amount of the tension of the wire 5) by visually checking the rotation amount of the winding shaft 73. Equivalent to. Further, a protrusion 751 pointing to the scale 714 may be provided at one place on the periphery of the knob portion 75.

  Next, another embodiment of the structure of a set of twisted string actuators including the plate-shaped fixing base 6, the drive mechanism 20, the slide guide 31, the twisted string 1, the slide member 32, etc. shown in FIG. Will be described. In FIG. 7 or FIG. 8, the drive mechanism unit 20 including a motor is placed and fixed on the fixed base 6 arranged around the arm or leg of the artificial limb (or robot hand). A recess may be formed on the surface of the table 6, and the entire or part of the drive mechanism unit 20 may be embedded in the recess. Such a structure is possible by downsizing the drive mechanism 20 and providing the fixed base 6 with a certain thickness.

  7 or 8, the proximal end side of the twisted string 1 is directly connected to the rotation output shafts 41 and 42. For example, as shown in FIG. 12A, the base end side of the twisted string 1 is formed on the rotation output shaft so that a small ring is formed by the string 1a passed through the through hole 411 provided at the distal end portion of the rotation output shaft 41. 41 is connected.

  However, in this connection method, for example, when the drive mechanism 20 is replaced, the base 1 of the twisted string 1 is rotated using the new string 1a after the string 1a is cut once and the drive mechanism 20 is replaced. It is necessary to connect to the output shaft 41 (or 42), and the work takes a lot of time. Therefore, as shown in FIG. 12B, a string fixing member 8 detachably attached to the rotation output shaft 41 ′ is connected in advance to the proximal end side of the twisted string 1. FIG. 12B shows a rotation output shaft 41 ′, which is a modification of one rotation output shaft 41, and a string fixing member 8 that is detachable from the rotation output shaft 41 ′, but the same applies to the other rotation output shaft 42 ′. .

  The string fixing member 8 has a substantially cylindrical shape made of metal such as resin or aluminum. A through hole 81 through which the twisted string 1 is inserted is formed on the distal end side (left side), and a hexagonal recess 82 is formed on the proximal end side (right side). On the distal end side of the rotation output shaft 41 ′, a hexagonal column protrusion 412 is formed which is inserted into and fitted into the recess 82 of the string fixing member 8. Further, through holes or screw holes 83 and 413 into which retaining pins or screws (not shown) are inserted are formed in the string fixing member 8 and the output shaft 41 ′ (projecting portions 412 thereof).

  Thus, by connecting the base end side of the twisted string 1 to the rotation output shaft 41 ′ (and 42 ′) via the string fixing member 8 that is detachable from the rotation output shaft 41 ′ (and 42 ′), for example, driving When the mechanism unit 20 is replaced, the work of temporarily disconnecting and reconnecting the twisted string 1 and the drive mechanism unit 20 is simplified.

  The shape of the fitting portion between the rotation output shaft 41 ′ (or 42 ′) and the string fixing member 8 is not necessarily limited to the hexagonal column and the hexagonal concave portion as shown in FIG. That is, the cross-section thereof is not limited to a hexagon, but may be another polygon such as a triangle or a quadrangle, or a shape lacking a semicircle or a part of a circle. Or you may employ | adopt the structure in which both are detachable by screwing of a male screw and a female screw.

  Although a plurality of embodiments and modifications of the present invention have been described above, the present invention is not limited to the above-described embodiments and modifications, and can be implemented in various forms.

It is a schematic diagram which shows the concept of the twisted string actuator which comprises the actuator unit for artificial limbs of this invention. It is a schematic diagram which shows the application example which drives a finger joint using a twisted string actuator. It is a schematic diagram which shows the example of application to the multiple finger joint of the twisted string actuator shown in FIG. It is a schematic diagram which shows the structural example which drives two twisted strings simultaneously with one motor. It is sectional drawing which shows the structure of the motor and gearbox of the twisted string actuator which concern on embodiment of this invention. It is a schematic diagram which shows the example of arrangement | positioning of 13 sets of twisted string actuators in the actuator unit for artificial limbs which concerns on embodiment of this invention. It is a perspective view which shows a part of actuator unit for artificial limbs concerning another embodiment of this invention. It is a perspective view which shows a part of actuator unit for artificial limbs concerning embodiment provided with the adjustment mechanism of this invention. It is a disassembled perspective view of an adjustment mechanism. It is a perspective view which shows the modification of the winding shaft which comprises an adjustment mechanism. It is a perspective view which shows the modification of an adjustment mechanism. It is a figure which shows the connection method of the base end side of a twisted string, and a rotation output shaft. It is a figure which shows the basic structure of the conventional wire type actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Twisted string 5 Wire 6 Fixing stand 7 Adjustment means 8 String fixing member 20 Drive mechanism part 32 Slide member 41, 42 Rotation output shaft 73 Winding shaft 75 Knob part 714 Scale (Adjustment amount grasping means)

Claims (5)

A twisted string having a structure in which two strings are twisted together, a drive mechanism portion having a rotation output shaft connected to the proximal end side of the twisted string, and a twisted string connected to the distal end side of the twisted string A slide member that is allowed to move only in the longitudinal direction; and a wire that is connected between the slide member and the drive target, and constitutes the twisted string when the rotation output shaft of the drive mechanism rotates. The length of the twisted string is changed by the strength change of the twist of the two strings, and as a result, the slide member is displaced in the longitudinal direction of the twisted string, and the displacement is applied to the driving object via the wire. A twisted string actuator to be transmitted,
A twisted string actuator characterized in that an adjusting means for adjusting the tension of the wire is provided at a connecting portion between the slide member and the wire. The twisted string actuator according to claim 1, wherein the adjusting means includes a winding shaft around which an end portion of the wire is wound, and a knob portion for manually rotating the winding shaft. An adjustment amount grasping unit that enables the adjustment unit to grasp the adjustment amount of the tension of the wire by visually checking the rotation amount of the winding shaft is further provided. Item 3. A twisted string actuator according to item 1 or 2. An actuator unit for a prosthetic limb that drives a plurality of finger joints to be driven using a plurality of sets of twisted string actuators according to claim 1, 2 or 3,
A plurality of actuator parts including the drive mechanism part, the twisted string, the slide member, and the adjusting means are arranged substantially in parallel, and these parts are fixed to a fixed base constituting the artificial limb. Actuator unit. A recess is formed in the surface of the fixed base in which all or part of the drive mechanism is embedded, and the rotation output shaft of the drive mechanism and the proximal end side of the twisted string are connected to the rotation output shaft. The prosthetic limb actuator unit according to claim 4, wherein the prosthetic limb actuator unit is formed through a detachable string fixing member.

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