Patent Publication Number: US-9889059-B2

Title: Finger joint driving device

Description:
BACKGROUND 
     1. Technical Field 
     The present invention is related to a finger joint driving device. 
     2. Related Art 
     A finger joint driving device which is mounted on a hand and assists movement of a finger in the mounted state, that is, which bends and stretches a finger joint has been known (for example, refer to JP-A-2002-345861). The finger joint driving device disclosed in JP-A-2002-345861 is provided with a slide bracket which is disposed on a back of the hand in the mounted state, a third connection member which is provided on the end side of the finger with respect to the slide bracket, and a third rear arm and a third front arm which are turnably provided with respect to the third connection member. In addition, the slide bracket slides, thus the third connection member slides, and together with this, the third rear arm and the third front arm turn in the opposite direction to each other, and thereby it is possible to bend the third joint of the finger. 
     However, in the finger joint driving device disclosed in JP-A-2002-345861, since the slide bracket is disposed on the back of the hand, the finger joint driving device is made thick as a whole. As a result, there is a problem in that when a user tries to put the hand in the mounted state into a relatively narrow gap, due to the finger joint driving device being mounted, the movement of the user is limited and, for example, the hand cannot be put into the gap. 
     SUMMARY 
     An advantage of some aspects of the invention is to provide a finger joint driving device capable of reducing the limitation of the movement of a user&#39;s hand when the user uses the finger joint driving device mounted on the hand. 
     The invention can be implemented as the following forms or application examples. 
     APPLICATION EXAMPLE 1 
     This application example is directed to a finger joint driving device which is provided on a hand and causes a finger joint to be turned, and includes: a first member that is mounted on the hand, a second member that is turnably provided on the first member, a third member that is turnably provided on the second member, a fourth member that is mounted on the end side of the finger from the first member and is provided on the third member so as to relatively approach with respect to and to be separated from the first member, and a first driving unit that drives at least one of the second member to be turned, the third member to be turned, and the fourth member to approach with respect to and to be separated from the first member. 
     With this configuration, it is possible to reduce the thickness of the finger joint driving device compared with a case where, for example, a member disposed on a back of the hand slides and thus a finger joint is allowed to bend and stretch. Thus, since the thickness of the finger joint driving device is reduced, it is possible to put the hand into a relatively narrow gap. Therefore, when using the finger joint driving device mounted on the hand, it is possible to reduce the limitation of the movement of a user&#39;s hand. 
     APPLICATION EXAMPLE 2 
     In the finger joint driving device according to the application example described above, it is preferable that the first member is disposed on the back of the hand and the fourth member is disposed on a knuckle of the finger. 
     With this configuration, according to a disposition state of the first member and the fourth member, it is possible to reliably turn the finger joint to be turned. 
     APPLICATION EXAMPLE 3 
     In the finger joint driving device according to the application example described above, it is preferable that the first member is disposed on the knuckle of the finger and the fourth member is disposed on a middle phalanx on the finger. 
     With this configuration, according to the disposition state of the first member and the fourth member, it is possible to reliably turn the finger joint to be turned. 
     APPLICATION EXAMPLE 4 
     In the finger joint driving device according to the application example described above, it is preferable that the first member is disposed on the middle phalanx of the finger and the fourth member is disposed on a distal phalanx of the finger. 
     With this configuration, according to the disposition state of the first member and the fourth member, it is possible to reliably turn the finger joint to be turned. 
     APPLICATION EXAMPLE 5 
     In the finger joint driving device according to the application example described above, it is preferable that the second member and the third member are turnable around an axis in parallel with a turning axis of the finger joint. 
     With this configuration, it is possible to reliably turn the finger joint to be turned. 
     APPLICATION EXAMPLE 6 
     In the finger joint driving device according to the application example described above, it is preferable that the first driving unit drives the second member to be turned. 
     With this configuration, it is possible to reliably perform the turning of the finger joint. 
     APPLICATION EXAMPLE 7 
     In the finger joint driving device according to the application example described above, it is preferable that the first driving unit drives the third member to be turned. 
     With this configuration, it is possible to reliably perform the turning of the finger joint. 
     APPLICATION EXAMPLE 8 
     In the finger joint driving device according to the application example described above, it is preferable that the first driving unit includes a piezoelectric element. 
     With this configuration, it is possible to make the configuration of the first driving unit, for example, a simple configuration using the piezoelectric element, thereby contributing to miniaturization and thickness reduction of the finger joint driving device. 
     APPLICATION EXAMPLE 9 
     It is preferable that the finger joint driving device according to the application example described above further includes a fifth member that is turnably provided on the fourth member, a sixth member that is turnably provided on the fifth member, and a seventh member that is mounted on the end side of the finger from the fourth member in the hand and is provided on the sixth member so as to relatively approach with respect to and to be separated from the fourth member. 
     With this configuration, it is possible to cause each of two finger joints to be turned. 
     APPLICATION EXAMPLE 10 
     It is preferable that the finger joint driving device according to the application example described above further includes a second driving unit that drives at least one of the fifth member to be turned, the sixth member to be turned, and the seventh member to approach with respect to and to be separated from the fourth member. 
     With this configuration, two finger joints are separated from each other or synchronized with each other and thus can be reliably turned. 
     APPLICATION EXAMPLE 11 
     This application example is directed to a finger joint driving device which is provided on a hand and causes a finger joint to be turned, and includes: a first member that is mounted on a hand, a second member that is turnably provided on the first member, a third member that is turnably provided on the second member, a fourth member that is mounted on the opposite side of the end side of the finger from the first member and is provided on the third member so as to relatively approach with respect to and to be separated from the first member, and a first driving unit that drives at least one of the second member to be turned, the third member to be turned, and the fourth member to approach with respect to and to be separated from the first member. 
     With this configuration, it is possible to reduce the thickness of the finger joint driving device compared with a case where, for example, a member disposed on a back of the hand slides and thus a finger joint is allowed to bend and stretch. Thus, since the thickness of the finger joint driving device is reduced, it is possible to put the hand into a relatively narrow gap. Therefore, when using the finger joint driving device mounted on the hand, it is possible to reduce the limitation of the movement of a user&#39;s hand. 
     The invention can also be implemented as the following application examples. 
     APPLICATION EXAMPLE 12 
     This application example is directed to a finger joint driving device which is provided on a hand and causes a finger joint to be turned, and includes: a first member that is mounted on the hand, a second member that is turnably provided on the first member, a third member that is provided on the second member so as to approach with respect to and to be separated from the first member, a fourth member that is mounted on the end side of the finger from the first member and is turnably provided on the third member, and a first driving unit that drives at least one of the second member to be turned, the third member to approach with respect to and to be separated from the first member, and the fourth member to be turned. 
     With this configuration, it is possible to reduce the thickness of the finger joint driving device compared with a case where, for example, a member disposed on a back of the hand slides and thus a finger joint is allowed to bend and stretch. Thus, since the thickness of the finger joint driving device is reduced, it is possible to put the hand into a relatively narrow gap. Therefore, when using the finger joint driving device mounted on the hand, it is possible to reduce the limitation of the movement of a user&#39;s hand. 
     APPLICATION EXAMPLE 13 
     In the finger joint driving device according to the application example described above, it is preferable that the first member is disposed on the back of the hand and the fourth member is disposed on a knuckle of the finger. 
     With this configuration, according to a disposition state of the first member and the fourth member, it is possible to reliably turn the finger joint to be turned. 
     APPLICATION EXAMPLE 14 
     In the finger joint driving device according to the application example described above, it is preferable that the first member is disposed on the knuckle of the finger and the fourth member is disposed on the middle phalanx on the finger. 
     With this configuration, according to the disposition state of the first member and the fourth member, it is possible to reliably turn the finger joint to be turned. 
     APPLICATION EXAMPLE 15 
     In the finger joint driving device according to the application example described above, it is preferable that the first member is disposed on the middle phalanx of the finger and the fourth member is disposed on a distal phalanx of the finger. 
     With this configuration, according to the disposition state of the first member and the fourth member, it is possible to reliably turn the finger joint to be turned. 
     APPLICATION EXAMPLE 16 
     In the finger joint driving device according to the application example described above, it is preferable that the second member and the fourth member are turnable around an axis parallel with a turning axis of the finger joint. 
     With this configuration, it is possible to reliably turn the finger joint to be turned. 
     APPLICATION EXAMPLE 17 
     In the finger joint driving device according to the application example described above, it is preferable that the first driving unit drives the second member to be turned. 
     With this configuration, it is possible to reliably perform the turning of the finger joint. 
     APPLICATION EXAMPLE 18 
     In the finger joint driving device according to the application example described above, it is preferable that the first driving unit drives the fourth member to be turned. 
     With this configuration, it is possible to reliably perform the turning of the finger joint. 
     APPLICATION EXAMPLE 19 
     In the finger joint driving device according to the application example described above, it is preferable that the first driving unit includes a piezoelectric element. 
     With this configuration, it is possible to make the configuration of the first driving unit, for example, a simple configuration using the piezoelectric element, thereby contributing to miniaturization and thickness reduction of the finger joint driving device. 
     APPLICATION EXAMPLE 20 
     It is preferable that the finger joint driving device according to the application example described above further includes a fifth member that is turnably provided on the fourth member, a sixth member that is provided on the fifth member so as to relatively approach with respect to and to be separated from the fourth member, and a seventh member that is turnably mounted on the sixth member. 
     With this configuration, it is possible to cause each of two finger joints to be turned. 
     APPLICATION EXAMPLE 21 
     It is preferable that the finger joint driving device according to the application example described above further includes a second driving unit that drives at least one of the fifth member to be turned, the sixth member to approach with respect to and to be separated from the fourth member, and the seventh member to be turned. 
     With this configuration, two finger joints are separated from each other or synchronized with each other and thus can be reliably turned. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a perspective view illustrating a usage state of a finger joint driving device according to a first embodiment. 
         FIG. 2  is a cross-sectional view taken along line A-A in  FIG. 1 . 
         FIG. 3  is a cross-sectional view illustrating a finger which is bent in the state illustrated in  FIG. 2 . 
         FIG. 4  is a plan view of a driving unit included in the finger joint driving device. 
         FIGS. 5A through 5C  are explanatory diagrams illustrating operating principles of the driving unit. 
         FIG. 6  is a cross-sectional view illustrating a usage state of a finger joint driving device according to a second embodiment. 
         FIG. 7  is a perspective view illustrating a usage state of a finger joint driving device according to a third embodiment. 
         FIG. 8  is a cross-sectional view taken along line A-A in  FIG. 7 . 
         FIG. 9  is a cross-sectional view illustrating a finger which is bent in the state illustrated in  FIG. 8 . 
         FIG. 10  is a cross-sectional view illustrating a usage state of a finger joint driving device according to a fourth embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, preferable embodiments according to a finger joint driving device according to the invention will be described in detail with reference to the drawings. Meanwhile, with respect to a hand  100 , a back of the hand  105  side is referred to as “up”, “the upper surface”, or the “upper side” and, a palm of the hand  106  side is referred to as “down”, the “lower surface”, or the “lower side” in the drawings. 
     First Embodiment 
       FIG. 1  is a perspective view illustrating a usage state of a finger joint driving device according to a first embodiment of the invention.  FIG. 2  is a cross-sectional view taken along line A-A in  FIG. 1 .  FIG. 3  is a cross-sectional view illustrating a finger which is bent in the state illustrated in  FIG. 2 .  FIG. 4  is a plan view of a driving unit included in the finger joint driving device as illustrated in  FIG. 1 .  FIGS. 5A to 5C  are explanatory diagrams illustrating operating principles of the driving unit. 
     Meanwhile, hereinafter, for the sake of convenience of description, fingers are schematically illustrated, and the obliquely left downward side is referred to as the “end side of the finger” and the opposite side which is the obliquely right upward side is referred to as the “wrist side” in  FIG. 1 , and the left side is referred to as “the end side of the finger” and the opposite side which is the right side is referred to as the “wrist side” in  FIG. 2  and  FIG. 3  (the same applies to  FIG. 6 ). In addition, the wrist front side is referred to as the “front side” and the opposite side which is the back side is referred to as the “rear side” in  FIG. 4 . 
     As illustrated in  FIG. 1 , the finger joint driving device  1  of the embodiment is mounted on an index finger  101  of a hand  100 . The hand  100  of the embodiment is a hand of a person, for example, who has trouble bending and stretching the finger due to an accident or illness, who has a weak grip, or who has weakened force because of age. The index finger  101  includes a knuckle  102 , a proximal interphalangeal joint  107 , a middle phalanx  103 , a distal interphalangeal joint  109 , and a distal phalanx  104 , and is configured in order from the knuckle  102  of the wrist side to the distal phalanx  104  of the end side of the finger. 
     The finger joint driving device  1  allows the finger joint of the index finger  101  to bend and stretch in a state where the finger joint driving device  1  is mounted on the hand  100  (the mounted state). That is, the finger joint driving device  1  is a device which is used to assist turning of the finger joint. 
     The finger joint driving device  1  is provided with a first base portion (a first member)  2 , a first link portion (a second member)  3 , a second link portion (a third member)  4 , and a second base portion (a fourth member)  5 , and these members are connected to each other in order from the wrist side toward the end side of the finger. Hereinafter, the configuration of the respective portions will be described. 
     As illustrated in  FIG. 1  to  FIG. 3 , the first base portion  2  is disposed on the back of the hand  105  side of the knuckle  102  of the index finger  101  in the mounted state, that is, on the upper side in the drawings. 
     The first base portion  2  is a member of which an external shape is a flat block shape, and includes a surface  21  and a side surface  22 . 
     The surface  21  which comes into contact with the knuckle  102  of the first base portion  2  is preferably bent along the shape of the knuckle  102 . Accordingly, the first base portion  2  is disposed on the knuckle  102  without giving a sense of discomfort to a user (a wearer) of the finger joint driving device  1 . Further, the first base portion  2  is stably disposed with respect to the knuckle  102 . 
     In addition, the first base portion  2  is mounted on the knuckle  102  of the index finger  101  by using a mounting band  20 A. The mounting band  20 A is configured of a length adjustable belt and end portions  20 T at both ends are respectively fixed to the two side surfaces  22  along the first base portion  2  in the extending direction. The mounting band  20 A can allow the first base portion  2  to be adhered to the knuckle  102  by going around a palm of the hand  106  side of the knuckle  102  of the index finger  101 . Therefore, it is possible to prevent the first base portion  2  from being separated from the knuckle  102 . 
     As illustrated in  FIG. 1  (the same is applied to  FIG. 2  and  FIG. 3 ), the second base portion  5  is disposed on the end side of the finger from the first base portion  2  in the mounted state, that is, disposed on the back of the hand  105  side of the middle phalanx  103  of the index finger  101 . Accordingly, as will be described later, it is possible to bend and stretch the proximal interphalangeal joint (the second joint)  107  between the knuckle  102  and the middle phalanx  103  of the index finger  101  by using the finger joint driving device  1  (refer to  FIG. 2  and  FIG. 3 ). 
     The second base portion  5  is a member of which an external shape is a flat block shape and includes a projection portion which projects from the upper surface of both end portions in the extending direction and of which the cross section is formed into a concave shape. The second base portion  5  includes a surface  51 , a side surface  52 , and a rail portion  53 . 
     The surface  51  which comes into contact with the middle phalanx  103  of the second base portion  5  is preferably bent along the shape of the middle phalanx  103 . Accordingly, the second base portion  5  is disposed on the middle phalanx  103  without giving a sense of discomfort to the user of the finger joint driving device  1 . Further, the second base portion  5  is stably disposed with respect to the middle phalanx  103 . 
     In addition, the second base portion  5  is mounted on the middle phalanx  103  of the index finger  101  by using a mounting band  20 B. The mounting band  20 B is configured of a length adjustable belt similar to the mounting band  20 A and the end portions  20 T at both ends are respectively fixed to the two side surfaces  52  along the second base portion  5  in the extending direction. The mounting band  20 B can allow the second base portion  5  to be adhered to the middle phalanx  103  by going around a palm of the hand  106  side of the middle phalanx  103  of the index finger  101 . Therefore, it is possible to prevent the second base portion  5  from being separated from the middle phalanx  103 . 
     The rail portion  53  is a pair of rails which are provided along the extending direction of the second base portion  5 . The rail portion  53  is provided such that both ends are fixed to the concave-shaped projection portion of the second base portion  5 , and the rest of both ends is positioned to be separated from a bottom surface of the concave shape. 
     As illustrated in  FIG. 1 , the first link portion  3  is provided on the end side of the finger of the first base portion  2 , and a portion thereof is provided at a position overlapping with the upper surface of the second base portion  5 . The first link portion  3  is a member of which the total length is greater than the total length of the first base portion  2  or the second base portion  5 . 
     The first link portion  3  includes a top plate  31  and side walls  32  which project from both edge portions along the extending direction of the top plate  31  toward the direction opposite to the index finger  101 . In addition, the two side walls  32  interpose a portion of the side surface  22  of the first base portion  2  therebetween. 
     In addition, each of the side walls  32  and the side surface  22  of the first base portion  2  are connected to each other via a turning support portion  11 . The turning support portion  11  is configured to have an axis which is provided on one of the side wall  32  and the side surface  22  and a bearing which has the axis inserted therein and is provided on the other of the side wall  32  and the side surface  22 . In addition, when a turning axis O 107  is assumed when the proximal interphalangeal joint  107  is turned by bending and stretching, a turning axis O 11  of the turning support portion  11  is in parallel with the turning axis O 107 . With such a configuration, the first link portion  3  can be turned around the turning axis O 11  with respect to the first base portion  2  by the turning support portion  11 . 
     The second link portion  4  is provided on the end side of the finger of the first link portion  3  and is provided to be positioned in the concave shape on the upper surface of the second base portion  5 . The second link portion  4  includes a sliding portion  41  sliding with respect to the second base portion  5  and a projection portion  42  which projects from a portion of the upper surface on the sliding portion  41  toward a perpendicular direction of the upper surface. 
     As illustrated in  FIG. 2  and  FIG. 3 , the sliding portion  41  is formed into a rectangular external shape, and includes a cylindrical hollow portion  411 . The rail portion  53  of the second base portion  5  is inserted into the hollow portion  411  of the sliding portion  41 . 
     Meanwhile, the total length of the rail portion  53  is sufficiently longer than the total length of the sliding portion  41 , for example, it is preferably 1.5 times to 3 times the total length of the sliding portion  41 , and more preferably 1.7 times to 2.3 times. 
     Since the sliding portion  41  slides while being guided by the rail portion  53 , the second base portion  5  can relatively approach with respect to and be separated from the first base portion  2 .  FIG. 2  illustrates a state where the second base portion  5  approaches with respect to the first base portion  2  and  FIG. 3  illustrates a state where the second base portion  5  is separated from the first base portion  2 . 
     The projection portion  42  is interposed between the two side walls  32  of the first link portion  3 . Then, the projection portion  42  and each of the side walls  32  are connected to each other via a turning support portion  12 . The turning support portion  12  is configured to have an axis which is provided on one of the projection portion  42  and the side wall  32  and a bearing which has the axis inserted therein and is provided on the other of the projection portion  42  and the side wall  32 . In addition, a turning axis O 12  of the turning support portion  12  is in parallel with the turning axis O 107 . 
     With such a configuration, similar to the first link portion  3 , the second link portion  4  can be turned around the turning axis O 12  which is in parallel with the turning axis O 107  by the turning support portion  12 . Since the turning axis O 11  and the turning axis O 12  are in parallel with the turning axis O 107 , it is possible to easily bend and stretch the proximal interphalangeal joint  107  by the finger joint driving device  1  while preventing unnecessary force from being applied to the proximal interphalangeal joint  107 . 
     Configuration materials of the first base portion  2 , the first link portion  3 , the second link portion  4 , and the second base portion  5  are not particularly limited and, for example, various kinds of resin materials such as polyethylene or various kinds of metallic materials such as aluminum can be used. In addition, configuration materials of the mounting bands  20 A and  20 B are not particularly limited; for example, various rubber materials such as silicone rubber can be used. 
     In addition, as illustrated in  FIG. 1 , the finger joint driving device  1  is further provided with the driving unit (the first driving unit)  6 A and a control unit  10  in the vicinity of the turning support portion  11 . 
     The driving unit  6 A is a mechanical portion which functions for driving the first link portion  3  to be turned via the turning support portion  11 . 
     As illustrated in  FIG. 4 , the driving unit  6 A includes a first rotor  61  which is concentrically connected to the axis of the turning support portion  11 , a second rotor  62  which causes the first rotor  61  to rotate, a third rotor which causes the second rotor  62  to rotate, and a piezoelectric motor  64  which causes the third rotor  63  to rotate. 
     The first rotor  61  is formed into a disk shape and is a gear including a tooth  611  at the external edge portion thereof. 
     The second rotor  62  includes a small gear  621  and a large gear  622 . The small gear  621  includes a tooth  621   a  which is engaged with the tooth  611  of the first rotor  61 . The large gear  622  is a gear of which a diameter of a base circle is larger than a diameter of a base circle of the small gear  621 . The large gear  622  is concentrically disposed with the small gear  621 , and is connected (fixed) to the rear side of the small gear  621 . 
     The third rotor  63  includes a small gear  631  and a large disk portion  632 . The small gear  631  includes a tooth  631   a  which is engaged with a tooth  622   a  of the large gear  622 . The large disk portion  632  is formed into a disk shape, and the diameter thereof is larger than the diameter of the base circle of the small gear  631 . The large disk portion  632  is concentrically disposed with the small gear  631 , and is connected to the front side of the small gear  631 . 
     The piezoelectric motor  64  includes a piezoelectric material exerting a piezoelectric effect, and is a stacked body which is configured to have two sheet-like piezoelectric elements  65  and a shim plate  66  which is formed of a metal flat plate and interposed between the piezoelectric elements  65  and bonded thereto. Hereinafter, the lateral direction of the piezoelectric motor  64  is referred to as an “x direction”, the width direction of the piezoelectric motor  64  which is orthogonal to the x direction is referred to as a “y direction”, and the thickness direction of the piezoelectric motor  64  which is orthogonal to the x direction and the y direction is referred to as a “z direction”. 
     Each of the piezoelectric elements  65  is provided with four electrodes  651  so as to apply the voltage to the piezoelectric element  65 . These electrodes  651  are disposed in a matrix state of two lines and two rows on the piezoelectric element  65 , and as a power supply source, batteries (not shown) such as button batteries are electrically connected to each other. 
     In addition, the shim plate  66  which is made of metal not only reinforces the piezoelectric element  65  but also serves as a common electrode for applying the voltage to the piezoelectric element  65 , and is grounded. 
     An end portion of the piezoelectric motor  64  in the +x direction is provided with a convex portion  67 . The convex portion  67  is integrally formed with the shim plate  66 . 
     Four supporting portions  68 , which support the piezoelectric motor  64  in a state of biasing toward the side on which the convex portion  67  is provided, are provided on both side surfaces of the piezoelectric motor  64  which face the ±y direction. These supporting portions  68  are integrally formed with the shim plate  66  and disposed on four corners of the shim plate  66  which is formed into a rectangular shape. Meanwhile, it is preferable that the supporting portions  68  which are adjacent in the x direction are connected to each other via a connection plate  69 . 
     The operating principles of the piezoelectric motor  64  in such a configuration will be described with reference to  FIGS. 5A to 5C . 
     The piezoelectric motor  64  is operated by an elliptical motion of the convex portion  67  of the piezoelectric motor  64  when the electrodes  651  of the respective piezoelectric elements  65  are periodically applied with the voltage. The convex portion  67  of the piezoelectric motor  64  performs the elliptical motion due to the following reason. Note that the electrodes  651  which are provided in the piezoelectric elements  65  are the same except for the disposition place, and thus the front side of the electrode  651  of the piezoelectric element  65  will be representatively described. 
     As is well known, the piezoelectric element  65  including the piezoelectric material has a property of extension when a positive voltage is applied to the piezoelectric element  65 . Accordingly, as illustrated in  FIG. 5A , when the positive voltage is applied to all of the four electrodes  651 , and then the applied voltage is repeatedly canceled at a particular frequency, the piezoelectric motor (the piezoelectric element  65 ) can generate a kind of resonance phenomenon in which the piezoelectric motor extends and contracts in the x direction. Meanwhile, an operation in which the piezoelectric motor  64  repeatedly extends and contracts in the x direction is referred to as an “extension and contraction vibration”, and the direction in which the piezoelectric motor  64  extends and contracts (the ±x direction in the drawings) is referred to as an “extension and contraction direction”. 
     In addition, as illustrated in  FIG. 5B  or  FIG. 5C , when two electrodes  651  which are positioned by each other on a diagonal line (a pair of an electrode  651   a  and an electrode  651   d  or a pair of an electrode  651   b  and an electrode  651   c ) are assumed to be a pair and the voltage at a particular frequency is applied to the two electrodes  651 , the piezoelectric motor (the piezoelectric element  65 ) can generate a kind of resonance phenomenon in which the tip end portion (a portion with which the convex portion  67  is provided) in the x direction moves in the vertical direction (the y direction) in the drawing. 
     For example, as illustrated in  FIG. 5B , when the positive voltage is periodically applied to the pair of the electrode  651   a  and the electrode  651   d , the piezoelectric motor  64  repeatedly operates the tip end portion in the x direction to move in the vertical direction. In addition, as illustrated in  FIG. 5C , when the positive voltage is periodically applied to the pair of the electrode  651   b  and the electrode  651   c , the piezoelectric motor  64  repeatedly operates the tip end portion in the x direction to move in the vertical direction. Such an operation of the piezoelectric motor  64  is referred to as a “bending vibration”. Hereinafter, the direction (the ±y direction) in which the piezoelectric motor  64  performs the bending vibration is referred to as a “bending direction”. 
     In addition, it is possible to concurrently derive a resonance of the “extension and contraction vibration” with a resonance of the “bending vibration” by appropriately selecting physical properties of the piezoelectric element  65  and dimensions of the piezoelectric element  65  (full length, width, and thickness). As a result, in a case where the voltage is applied to the pair of the electrode  651   a  and the electrode  651   d  in a state illustrated in  FIG. 5B , the tip end portion (a portion with which the convex portion  67  is provided) of the piezoelectric motor  64  performs an operation (the elliptical motion) of turning clockwise as if drawing an ellipse in the drawing. In addition, in a case where the voltage is applied to the pair of the electrode  651   b  and the electrode  651   c  in a state illustrated in  FIG. 5C , the tip end portion of the piezoelectric motor  64  performs the elliptical motion of turning counterclockwise in the drawing. The piezoelectric element  65  of the rear side has exactly the same configuration as that of the piezoelectric motor  64  of the front side. 
     The piezoelectric motor  64  drives the first link portion  3  which is a driven body by using such an elliptical motion. 
     That is, the elliptical motion is generated in a state in which the convex portion  67  of the piezoelectric motor  64  is pressed to an external edge portion  632   a  of the large disk portion  632  of the third rotor  63 . Accordingly, the convex portion  67  moves from the left to the right (or from the right to the left) in a state of being pressed to the driven body when the piezoelectric motor  64  extends; on the other hand, the convex portion  67  returns back to the previous position in a state of being separated from the driven body when the piezoelectric motor  64  contracts, and the convex portion  67  repeats the above operations. As a result, the third rotor  63  rotates in one direction due to the friction force received from the convex portion  67 . Then, such a rotating force is transferred via the small gear  631  of the third rotor  63 , the large gear  622  of the second rotor, the small gear  621 , and the first rotor  61  in order. Accordingly, it is possible to drive the first link portion  3  to be turned via the turning support portion  11 . 
     In the finger joint driving device  1 , it is possible to reliably drive the first link portion  3  to be turned with a simple configuration by using the piezoelectric element  65 . In addition, the configuration using the piezoelectric element  65  contributes to miniaturization and thickness reduction of the finger joint driving device  1 . 
     In addition, the piezoelectric motor  64  is preferable because the piezoelectric motor  64  gets a higher resolution as the proximal interphalangeal joint  107  of the index finger  101  further bends to grasp. 
     Meanwhile, the driving unit  6 A functions for driving the first link portion  3  to be turned in the embodiment, but may function for driving the second link portion  4  to be turned. Similarly, in this case, it is possible to reliably drive the second link portion  4  to be turned and to contribute to miniaturization and thickness reduction of the finger joint driving device  1 . 
     The control unit  10  controls the operation of the driving unit  6 A based on a program which is recorded in advance. The control unit  10  is, for example, built into the second link portion  4  together with a battery (not shown) such as a button battery which supplies electric power to the driving unit  6 A. Meanwhile, the configuration of the control unit  10  is not particularly limited. For example, it is possible to employ a configuration including a microprocessor and a memory. 
     Next, the operation of the finger joint driving device  1  will be described. 
     In the state illustrated in  FIG. 2 , in the finger joint driving device  1 , the first base portion  2  is mounted on the knuckle  102  of the index finger  101  and the second base portion  5  is mounted on the middle phalanx  103 . Then, when the driving unit  6 A is operated in this state as described above, as illustrated in  FIG. 3 , it is possible to turn the second link portion  4  in the counterclockwise direction in the drawing. Therefore, the middle phalanx  103  of the index finger  101  is pressed together with the second base portion  5  on the obliquely right downward side in  FIG. 3 . As a result, the proximal interphalangeal joint  107  of the index finger  101  is bent. 
     In addition, if the second link portion  4  is turned in the direction opposite to the turning direction from the state illustrated in  FIG. 3 , in other words, the second link portion  4  is turned clockwise in the drawing, as illustrated in  FIG. 2 , the middle phalanx  103  of the index finger  101  is pulled together with the second base portion  5  on the obliquely left upward side in the drawings. As a result, the proximal interphalangeal joint  107  of the index finger  101  extends. 
     Further, if the proximal interphalangeal joint  107  is bent (or extends), the second base portion  5  is separated (or approaches with respect to) from the first base portion  2 . However, as described above, since the second link portion  4  and the second base portion  5  are relatively movable, the second base portion  5  is quickly and smoothly separated (or approaches with respect to) from the first base portion  2 . Accordingly, it is possible to easily bend the proximal interphalangeal joint  107 , thereby reducing a burden to the index finger  101 . 
     In addition, the user of the finger joint driving device  1  can bend and stretch the distal interphalangeal joint  109  of the index finger  101 , a thumb, a middle finger, a ring finger, and a little finger which are not assisted by the finger joint driving device  1  separately from the proximal interphalangeal joint  107  of the index finger  101 . 
     Further, for example, the finger joint driving device  1  can suppress the thickness of the entire device compared with a configuration in which the member which is disposed on the back of the hand  105  slides and thus the finger joint is allowed to bend and stretch (for example, refer to JP-A-2002-345861). Accordingly, when the user uses the finger joint driving device  1  mounted on the hand, it is possible to reduce the limitation of the movement of a user&#39;s hand. 
     In addition, since the second link portion  4  and the second base portion  5  are relatively movable in the middle phalanx  103  of the index finger  101  side, it is possible to mount the finger joint driving device  1  without depending on the length of the index finger  101 , thereby realizing high versatility. 
     Meanwhile, in the finger joint driving device  1  in the mounted state, the first base portion  2  is disposed on the knuckle  102  of the index finger  101  and the second base portion  5  is disposed on the middle phalanx  103  in the embodiment; however, such a disposition is not limited. 
     For example, in the mounted state, the first base portion  2  may be disposed on the back of the hand  105  and the second base portion  5  may be disposed on the knuckle  102  of the index finger  101 . In this case, it is possible to bend and stretch the metacarpophalangeal joint (the third joint)  108  by the finger joint driving device  1 . 
     Additionally, in the mounted state, the first base portion  2  may be disposed on the middle phalanx  103  of the index finger  101  and the second base portion  5  may be disposed on the distal phalanx  104 . In this case, it is possible to bend and stretch the distal interphalangeal joint (the first joint)  109  by the finger joint driving device  1 . 
     In addition, in the mounted state, the first base portion  2  may be disposed on the middle phalanx  103  of the index finger  101  and the second base portion  5  may be disposed on the knuckle  102  of the wrist side from the first base portion  2 . In this case, similar to the mounted state in the embodiment, it is possible to bend and stretch the proximal interphalangeal joint  107  by the finger joint driving device  1 . 
     As described above, it is possible to preferentially assist the finger joint to be bent and stretched, and therefore, it is possible to flexibly perform various assist operations with response to the usage state. 
     Further, the mounting position of the finger joint driving device  1  with respect to the hand  100  is the index finger  101  in the embodiment; however, the mounting position is not limited. For example, the thumb, the middle finger, the ring finger, or the little finger may be used as the mounting position. 
     Second Embodiment 
       FIG. 6  is a cross-sectional view illustrating a usage state of a finger joint driving device according to a second embodiment. 
     Hereinafter, the finger joint driving device of the second embodiment will be described with reference to drawings, but the description will focus on the differences from the embodiments described above and the same matters will be omitted. 
     The finger joint driving device  201  according to the embodiment is configured to bend and stretch not only the proximal interphalangeal joint  107  but also the distal interphalangeal joint  109 , and the end portion on the end side of the finger of the second base portion  205  is connected to the third link portion (the fifth member)  7 , and thus is the same as the finger joint driving device  1  in the first embodiment other than a point that the thickness is large compared with the second base portion  5  in the first embodiment. 
     As illustrated in  FIG. 6 , the finger joint driving device  201  is provided with a third link portion (the fifth member)  7 , a fourth link portion (the sixth member)  8 , and a third base portion (the seventh member)  9  in addition to the first base portion  2 , first link portion  3 , and the second base portion  205 , and these members are connected to each other in order from the wrist side to the end side of the finger. 
     The third base portion  9  is disposed on the end side of the finger from the second base portion  205  (the third link portion  7 ) in the mounted state, that is, disposed on the back of the hand  105  side of the distal phalanx  104  of the index finger  101 . Accordingly, as will be described later, it is possible to bend and stretch the distal interphalangeal joint  109  between the middle phalanx  103  and the distal phalanx  104  of the index finger  101  by using the finger joint driving device  201 . 
     The third base portion  9  is a member of which an external shape is a flat block shape similar to the second base portion  5  in the first embodiment. The third base portion  9  includes a surface  91  and a rail portion  93 . 
     The surface  91  which comes into contact with the distal phalanx  104  of the third base portion  9  is preferably bent along the shape of the distal phalanx  104 . Accordingly, the third base portion  9  is disposed on the distal phalanx  104  without giving a sense of discomfort to the user of the finger joint driving device  201 . Further, the third base portion  9  is stably disposed with respect to the distal phalanx  104 . 
     In addition, the third base portion  9  is mounted on the distal phalanx  104  of the index finger  101  by using a mounting band  20 C. The mounting band  20 C is configured of a length adjustable belt similar to the mounting band  20 A and both end portions are respectively fixed to the two side surfaces along the third base portion  9  in the extending direction. The mounting band  20 C can allow the third base portion  9  to be adhered to the distal phalanx  104  by going around a palm of the hand  106  side of the distal phalanx  104  of the index finger  101 . Therefore, it is possible to prevent the third base portion  9  from being separated from the distal phalanx  104 . 
     Since the rail portion  93  has the same structure as that of the rail portion  53  in the first embodiment, the description thereof will be omitted. 
     The third link portion  7  is provided on the end side of the finger of the second base portion  205 , and a portion thereof is provided at the position overlapping with the upper surface of the third base portion  9 . The third link portion  7  is a member of which the total length is the same as the total length of the first link portion  3 . 
     The third link portion  7  includes a top plate  71  and side walls  72  which project from both edge portions along the extending direction of the top plate  71  toward the direction opposite to the index finger  101 . In addition, the two side walls  72  interpose a portion of the side surface provided on the end portion of the end side of the finger of the second base portion  205  therebetween. 
     In addition, each of the side walls  72  and the side surface of the second base portion  205  are connected to each other via a turning support portion  13 . The turning support portion  13  is configured to have an axis which is provided on one of the side wall  72  and the second base portion  205  and a bearing which has the axis inserted therein and is provided on the other of the side wall  72  and the second base portion  205 . In addition, when a turning axis is assumed when the distal interphalangeal joint  109  is turned by bending and stretching, a turning axis of the turning support portion  13  is in parallel with the turning axis of the distal interphalangeal joint  109 . With such a configuration, the third link portion  7  can be turned around the turning axis of the turning support portion  13  with respect to the second base portion  205  by the turning support portion  13 . 
     The fourth link portion  8  is provided on the end side of the finger of the third link portion  7  and is provided to be positioned in the concave shape on the upper surface of the third base portion  9 . The fourth link portion  8  includes a sliding portion  81  sliding with respect to the third base portion  9  and a projection portion  82  which projects from a portion on the upper surface of the sliding portion  81  toward perpendicular direction of the upper surface. 
     Similar to the sliding portion  41  as illustrated in  FIG. 2  and  FIG. 3 , the sliding portion  81  is formed into a rectangular external shape, and includes a cylindrical hollow portion  811 . The rail portion  93  of the third base portion  9  is inserted into the hollow portion  811  of the sliding portion  81 . 
     Meanwhile, the total length of the rail portion  93  is sufficiently longer than the total length of the sliding portion  81 , for example, it is preferably 1.5 times to 3 times the total length of the sliding portion  81 , and more preferably 1.5 times to 2 times. 
     Since the sliding portion  81  slides while being guided by the rail portion  93 , the third base portion  9  can relatively approach with respect to and be separated from the second base portion  205 . 
     The projection portion  82  is interposed between the two side walls  72  of the third link portion  7 . Then, the projection portion  82  and each of the side walls  72  are connected to each other via a turning support portion  14 . The turning support portion  14  is configured to have an axis which is provided on one of the projection portion  82  and the side wall  72  and a bearing which has the axis inserted therein and is provided on the other of the projection portion  82  and the side wall  72 . In addition, a turning axis of the turning support portion  14  is in parallel with the turning axis of the distal interphalangeal joint  109 . 
     With such a configuration, similar to the third link portion  7 , the fourth link portion  8  can be turned around the turning axis of the turning support portion  14  which is in parallel with the turning axis of the distal interphalangeal joint  109  by the turning support portion  14 . 
     Since the turning axis of the turning support portion  13  and the turning axis of the turning support portion  14  are in parallel with the turning axis of the distal interphalangeal joint  109 , it is possible to easily bend and stretch the distal interphalangeal joint  109  by the finger joint driving device  201  while preventing unnecessary force from being applied to the distal interphalangeal joint  109 . 
     Configuration materials of the third link portion  7 , the fourth link portion  8 , and the third base portion  9  are not particularly limited, for example, it is possible to use the same configuration materials as that of the first base portion  2 . In addition, configuration materials of the mounting band  20 C are not particularly limited, for example, it is possible to use the same configuration materials as that of the mounting band  20 A. 
     In addition, as illustrated in  FIG. 6 , the finger joint driving device  201  is further provided with the driving unit (the second driving unit)  6 B in the vicinity of the turning support portion  14 . 
     The driving unit  6 B is a mechanical portion which functions for driving the fourth link portion  8  to be turned via the turning support portion  14 . In addition, the proximal interphalangeal joint  107  and the distal interphalangeal joint  109  of the index finger  101  are separated from each other or synchronized to each other by the driving unit  6 A and the driving unit  6 B, and thus can be reliably turned. Accordingly, since the number of the joint portions that assist the user increases, the hand of the operation becomes easier. 
     Meanwhile, similar to the configuration of the driving unit  6 A, that is, the driving unit  6 B is configured to include the first rotor  61 , the second rotor  62 , the third rotor  63 , and the piezoelectric motor  64  which causes the third rotor  63  to rotate. Therefore, it is possible to use common components in the configuration components of the driving unit  6 A and the driving unit  6 B, and thus, it is possible to reduce the manufacturing cost of the finger joint driving device  201 . 
     In addition, the driving unit  6 B functions for driving the fourth link portion  8  (the turning support portion  14 ) to be turned in the embodiment, but may function for driving the third link portion  7  (the turning support portion  13 ) to be turned. 
     Third Embodiment 
       FIG. 7  is a perspective view illustrating a usage state of a finger joint driving device according to a third embodiment of the invention.  FIG. 8  is a cross-sectional view taken along line A-A in  FIG. 7 .  FIG. 9  is a cross-sectional view illustrating a finger which is bent in the state illustrated in  FIG. 8 . Note that, hereinafter, for the sake of convenience of description, obliquely left downward side is referred to as the “end side of the finger” and the opposite side is referred to as the “wrist side” in  FIG. 7 , and the left side is referred to as the “end side of the finger” and the opposite side is referred to as the “wrist side” in  FIG. 8  and  FIG. 9  (the same is applied to  FIG. 10 ). 
     Hereinafter, the finger joint driving device of the third embodiment will be described with reference to drawings, but the description will focus on the differences from the embodiments described above and the same matters will be omitted. 
     As illustrated in  FIG. 7 , a finger joint driving device  301  of the embodiment is mounted on an index finger  101  of a hand  100 . The description of the hand  100  and the index finger  101  is the same as those of the above embodiments, and thus will be omitted. 
     The finger joint driving device  301  allows the finger joint of the index finger  101  to bend and stretch in a state where the finger joint driving device  301  is mounted on the hand  100  (the mounted state). That is, the finger joint driving device  301  is a device which is used to assist turning of the finger joint. 
     The finger joint driving device  301  is provided with a first base portion (the first member)  302 , a first link portion (the second member)  303 , a second link portion (the third member)  304 , and a second base portion (the fourth member)  305 , and these members are connected to each other in order from the wrist side toward the end side of the finger. Hereinafter, the configuration of the respective portions will be described. 
     As illustrated in  FIG. 7  to  FIG. 9 , the first base portion  302  is disposed on the back of the hand  105  side of the knuckle  102  of the index finger  101  in the mounted state, that is, on the upper side in the drawings. 
     The first base portion  302  is a member of a flat block shape, and includes a surface  321  and a projection portion  322 . The surface  321  which comes into contact with the knuckle  102  of the first base portion  302  is preferably bent along the shape of the knuckle  102 . Accordingly, the first base portion  302  is disposed on the knuckle  102  without giving a sense of discomfort to a user (a wearer) of the finger joint driving device  301 . Further, the first base portion  302  is stably disposed with respect to the knuckle  102 . 
     In addition, the first base portion  302  is mounted on the knuckle  102  of the index finger  101  by using a mounting band  20 A. Since the configuration of the mounting band  20 A is the same as that in the first embodiment, the description will be omitted. The mounting band  20 A can allow the first base portion  302  to be adhered to the knuckle  102  by going around a palm of the hand  106  side of the knuckle  102  of the index finger  101 . Therefore, it is possible to prevent the first base portion  302  from being separated from the knuckle  102 . 
     The projection portion  322  is formed into a rectangular shape projected to the direction perpendicular to the upper surface in the end portion of the end side of the finger on the upper surface of the first base portion  302  which forms a rectangular shape in a planar view. Meanwhile, the projection portion  322 , of which the width along the short side direction of the upper surface is smaller than the width of the first base portion  302 , is formed in the vicinity of the center in the width direction. 
     The second base portion  305  is disposed on the end side of the finger from the first base portion  302  in the mounted state, that is, disposed on the back of the hand  105  side of the middle phalanx  103  of the index finger  101 . Accordingly, as will be described later, it is possible to bend and stretch the proximal interphalangeal joint (the second joint)  107  between the knuckle  102  and the middle phalanx  103  of the index finger  101  by using the finger joint driving device  301  (refer to  FIG. 8  and  FIG. 9 ). 
     The second base portion  305  is a member which is formed into a flat block shape and includes a surface  351  and a pair of the convex portions  352 . The surface  351  which comes into contact with the middle phalanx  103  of the second base portion  305  is preferably bent along the shape of the middle phalanx  103 . Accordingly, the second base portion  305  is disposed on the middle phalanx  103  without giving a sense of discomfort to the user of the finger joint driving device  301 . Further, the second base portion  305  is stably disposed with respect to the middle phalanx  103 . 
     In addition, the second base portion  305  is mounted on the middle phalanx  103  of the index finger  101  by using a mounting band  20 B. Since the configuration of the mounting band  20 B is the same as that in the first embodiment, the description will be omitted. The mounting band  20 B can allow the second base portion  305  to be adhered to the middle phalanx  103  by going around a palm of the hand  106  side of the middle phalanx  103  of the index finger  101 . Therefore, it is possible to prevent the second base portion  305  from being separated from the middle phalanx  103 . 
     The convex portions  352  which are formed into a rectangular shape in a planar view are projected from two corners of the wrist side and separated from each other. 
     As illustrated in  FIG. 7 , the first link portion  303  is provided on the end side of the finger of the first base portion  302 . The first link portion  303  includes a bottom plate  331  which is formed into a rectangular shape in a planar view and projections  332  which are projected from four corners of the bottom plate  331 . 
     In addition, the projection portion  322  of the first base portion  302  is interposed between two projections  332  on the first base portion  302  side (the wrist side). 
     Further, in the first link portion  303 , two projections  332  on the first base portion  302  side and the projection portion  322  on the first base portion  302  are connected to each other via a turning support portion  311 . The turning support portion  311  is configured to have an axis which is provided on one of a pair of the projections  332  and the first base portion  302  (the projection portion  322 ) of the back of the hand  105  side and a bearing which has the axis inserted therein and is provided on the other of a pair of the projections  332  and the first base portion  302 . 
     In addition, when a turning axis O 107  is assumed when the proximal interphalangeal joint  107  is turned by bending and stretching, a turning axis O 311  of the turning support portion  311  is in parallel with the turning axis O 107 . With such a configuration, the first link portion  303  can be turned around the turning axis O 311  with respect to the first base portion  302  by the turning support portion  311 . 
     In addition, each of rail portions  333  is installed between two projections  332  which are positioned on the thumb side in the mounted state and between two projections  332  which are positioned on the middle finger in the mounted state. 
     A second link portion  304  is provided on the end side of the finger of the first link portion  303  and a portion thereof is provided at a position overlapping with the upper surface of the first link portion  303 . The second link portion  304  is a member of turning with respect to the second base portion  305 . 
     In addition, the second link portion  304  includes a linear long length portion  341  and a pair of the projection portions  342  which are projected from the long length portion  341 , and is formed of a plate piece of which an external shape is substantially a T shape. Specifically, a pair of the projection portions  342  are projected in the direction intersecting with the lateral direction of the long length portion  341  from the end portion of the first base portion  302  side of the long length portion  341 , and projected toward the opposite sides. 
     In addition, each of the projection portions  342  includes a hollow portion  421  which is penetrated in a cylindrical shape and a pair of rail portions  333  of the first link portion  303  are respectively inserted into each of the hollow portions  421 . 
     Since the projection portion  342  slides while being guided by the rail portion  333 , the second link portion  304  can relatively approach with respect to and be separated from the first base portion  302 .  FIG. 8  illustrates a state where the second link portion  304  approaches with respect to the first base portion  302  and  FIG. 9  illustrates a state where the second link portion  304  is separated from the first base portion  302 . 
     Meanwhile, the total length of the rail portion  333  is sufficiently longer than the total length of the projection portion  342  (the hollow portion  421 ), for example, it is preferably 1.5 times to 3 times the total length of the projection portion  342 , and more preferably 1.7 times to 2.3 times. 
     The tip end portion of the long length portion  341  is interposed between a pair of the convex portions  352  of the second base portion  305 . Then, the end portion of the end side of the finger of the long length portion  341  and each of the convex portions  352  are connected to each other via a turning support portion  312 . The turning support portion  312  is configured to have an axis which is provided on one of the end portion of the end side of the finger of the long length portion  341  and each of the convex portions  352  and a bearing which has the axis inserted therein and is provided on the other of the end portion of the end side of the finger of the long length portion  341  and each of the convex portions  352 . 
     In addition, a turning axis O 312  of the turning support portion  312  is in parallel with the turning axis O 107 . With such a configuration, similar to the first link portion  303 , the second base portion  305  can be turned around the turning axis O 312  which is in parallel with the turning axis O 107  by the turning support portion  312 . Since the turning axis O 311  and the turning axis O 312  are in parallel with the turning axis O 107 , it is possible to easily bend and stretch the proximal interphalangeal joint  107  by the finger joint driving device  301  while preventing unnecessary force from being applied to the proximal interphalangeal joint  107 . 
     Configuration materials of the first base portion  302 , the first link portion  303 , the second link portion  304 , and the second base portion  305  are not particularly limited, for example, various kinds of resin materials such as polyethylene or various kinds of metallic materials such as aluminum can be used. In addition, configuration materials of the mounting bands  20 A and  20 B are not particularly limited, for example, various rubber materials such as silicone rubber can be used. 
     In addition, as illustrated in  FIG. 7 , the finger joint driving device  301  is further provided with the driving unit (the first driving unit)  306 A and a control unit  310  in the vicinity of the projection portion  322 . 
     The driving unit  306 A is a mechanical portion which functions for driving the first link portion  303  to be turned via the turning support portion  311 . 
     Since the driving unit  306 A has the same structure as that of the driving unit  6 A illustrated in  FIG. 4  and  FIGS. 5A and 5C  of the first embodiment, the explanation thereof will be omitted. 
     The piezoelectric motor  64  drives the first link portion  303  which is a driven body by using such an elliptical motion as illustrated in  FIGS. 5A to 5C . 
     Accordingly, it is possible to drive the second base portion  305  to be turned via the turning support portion  311 . 
     In the finger joint driving device  301 , it is possible to reliably drive the first link portion  303  to be turned with a simple configuration by using the piezoelectric element  65 . In addition, the configuration using the piezoelectric element  65  contributes to miniaturization and thickness reduction of the finger joint driving device  301 . 
     In addition, the piezoelectric motor  64  is preferable because the piezoelectric motor  64  gets a higher resolution as the proximal interphalangeal joint  107  of the index finger  101  further stretches. 
     Meanwhile, the driving unit  306 A functions for driving the first link portion  303  to be turned in the embodiment, but may function for driving the second base portion  305  to be turned. Similarly, in this case, it is possible to reliably drive the second base portion  305  to be turned and to contribute to miniaturization and thickness reduction of the finger joint driving device  301 . 
     The control unit  310  controls the operation of the driving unit  306 A based on a program which is recorded in advance. The control unit  310  is, for example, built into the second link portion  304  together with a battery (not shown) such as a button battery which supplies electric power to the driving unit  306 A. Meanwhile, the configuration of the control unit  310  is not particularly limited. For example, it is possible to employ a configuration including a microprocessor and a memory. 
     Next, the operation of the finger joint driving device  301  will be described. 
     In the state illustrated in  FIG. 8 , in the finger joint driving device  301 , the first base portion  302  is mounted on the knuckle  102  of the index finger  101  and the second base portion  305  is mounted on the middle phalanx  103 . Then, when the driving unit  306 A is operated from this state so as to be described above, as illustrated in  FIG. 9 , it is possible to turn the second link portion  304  in the counterclockwise direction in the drawing. Therefore, the middle phalanx  103  of the index finger  101  is pressed together with the second base portion  305  on the obliquely right downward side in FIG.  9 . As a result, the proximal interphalangeal joint  107  of the index finger  101  is bent. 
     In addition, if the first link portion  303  is turned in the direction opposite to the turning direction from the state illustrated in  FIG. 9 , in other words, the first link portion  303  is turned clockwise in the drawing, as illustrated in  FIG. 8 , the middle phalanx  103  of the index finger  101  is pulled on the obliquely left upward side in the drawings. As a result, the proximal interphalangeal joint  107  of the index finger  101  extends. 
     Further, if the proximal interphalangeal joint  107  is bent (or extends), the second base portion  305  is separated (or approaches with respect to) from the first base portion  302 . However, as described above, since the first link portion  303  and the second link portion  304  are relatively movable, the second base portion  305  is quickly and smoothly separated (or approaches with respect to) from the first base portion  302 . Accordingly, it is possible to easily bend the proximal interphalangeal joint  107 , thereby reducing a burden to the index finger  101 . 
     In addition, the user of the finger joint driving device  301  can bend and stretch the distal interphalangeal joint  109  of the index finger  101 , a thumb, a middle finger, a ring finger, and a little finger which are not assisted by the finger joint driving device  301  separately from the proximal interphalangeal joint  107  of the index finger  101 . 
     Further, for example, the finger joint driving device  301  can suppress the thickness of the entire device compared with a configuration in which, the member which is disposed on the back of the hand  105  slides and thus the finger joint is allowed to bend and stretch (for example, refer to JP-A-2002-345861). Accordingly, when the user uses the finger joint driving device  301  mounted on the hand, it is possible to reduce the limitation of the movement of a user&#39;s hand. 
     In addition, since the first link portion  303  and the second link portion  304  between the knuckle  102  and the middle phalanx  103  of the index finger  101  are relatively movable, it is possible to mount the finger joint driving device  301  without depending on the length of the index finger  101 , thereby realizing high versatility. 
     Meanwhile, in the finger joint driving device  301  in the mounted state, the first base portion  302  is disposed on the knuckle  102  of the index finger  101  and the second base portion  305  is disposed on the middle phalanx  103  in the embodiment; however, such a disposition is not limited. For example, in the mounted state, the first base portion  302  may be disposed on the back of the hand  105  and the second base portion  305  may be disposed on the knuckle  102  of the index finger  101 . In this case, it is possible to bend and stretch the metacarpophalangeal joint (the third joint)  108  by the finger joint driving device  301 . Additionally, in the mounted state, the first base portion  302  may be disposed on the middle phalanx  103  of the index finger  101  and the second base portion  305  may be disposed on the distal phalanx  104 . In this case, it is possible to bend and stretch the distal interphalangeal joint (the first joint)  109  by the finger joint driving device  301 . 
     As described above, it is possible to preferentially assist the finger joint to be bent and stretched, and therefore, it is possible to flexibly perform various assist operations with response to the usage state. 
     Further, the mounting position of the finger joint driving device  301  with respect to the hand  100  is the index finger  101  in the embodiment; however, the mounting position is not limited. For example, the thumb, the middle finger, the ring finger, or the little finger may be used as the mounting position. 
     Fourth Embodiment 
       FIG. 10  is a cross-sectional view illustrating a usage state of a finger joint driving device according to a fourth embodiment. 
     Hereinafter, a finger joint driving device  501  of the fourth embodiment will be described with reference to  FIG. 10 , but the description will focus on the differences from the embodiments described above and the same matters will be omitted. 
     According to the embodiment is configured to bend and stretch not only the proximal interphalangeal joint  107  but also the distal interphalangeal joint  109 , and the end portion on the end side of the finger of the second base portion  505  is connected to the third link portion (the fifth member)  307 , and thus is the same as the finger joint driving device  301  in the third embodiment other than a point that the thickness is large compared with the second base portion  305  in the third embodiment. 
     As illustrated in  FIG. 10 , the finger joint driving device  501  is provided with a third link portion (the fifth member)  307 , a fourth link portion (the sixth member)  308 , and a third base portion (the seventh member)  309  in addition to the first base portion  302 , the first link portion  303 , the second link portion  304 , and the second base portion  305 , and these members are connected to each other in order from the wrist side to the end side of the finger. 
     The third base portion  309  is disposed on the end side of the finger from the second base portion  305  (the third link portion  307 ) in the mounted state, that is, disposed on the back of the hand  105  side of the distal phalanx  104  of the index finger  101 . Accordingly, as will be described later, it is possible to bend and stretch the proximal interphalangeal joint  109  between the middle phalanx  103  and the distal phalanx  104  of the index finger  101  by using the finger joint driving device  501 . 
     Similar to the second base portion  305  in the third embodiment, the third base portion  309  is a member which is formed into a flat block shape. In addition, a surface  391  which comes into contact with the distal phalanx  104  of the third base portion  309  is preferably bent along the shape of the distal phalanx  104 . Accordingly, the third base portion  309  is disposed on the distal phalanx  104  without giving a sense of discomfort to the user of the finger joint driving device  501 . Further, the third base portion  309  is stably disposed with respect to the distal phalanx  104 . 
     In addition, the third base portion  309  is mounted on the distal phalanx  104  of the index finger  101  by using a mounting band  20 C. Since the configuration of the mounting band  20 C is the same as that in the second embodiment, the description will be omitted. The mounting band  20 C can allow the third base portion  309  to be adhered to the distal phalanx  104  by going around a palm of the hand  106  side of the distal phalanx  104  of the index finger  101 . Therefore, it is possible to prevent the third base portion  309  from being separated from the distal phalanx  104 . 
     The third link portion  307  is provided on the end side of the finger of the second base portion  505 . The third link portion  307  is a member having the same total length as that of the first link portion  303 . The third link portion  307  includes a bottom plate  371  which is formed into a rectangular shape in a planar view and projections  372  which are projected from four corners of the bottom, plate  371 . The convex portion  352  of the second base portion  505  is interposed between two projections  372  on the second base portion  505  side. 
     Further, two projections  372  on the second base portion  505  side and the convex portion  352  of the second base portion  505  are connected to each other via a turning support portion  313 . The turning support portion  313  is configured to have an axis which is provided on one of each of the projections  372  and the second base portion  505  of the back of the hand  105  side and a bearing which has the axis inserted therein and is provided on the other of each of the projections  372  and the second base portion  505  of the back of the hand  105  side. 
     In addition, when a turning axis O 109  is assumed when the distal interphalangeal joint  109  is turned by bending and stretching, a turning axis O 313  of the turning support portion  313  is in parallel with the turning axis O 109 . With such a configuration, the third link portion  307  can be turned around the turning axis O 313  with respect to the second base portion  505  by the turning support portion  313 . 
     In addition, each of rail portions  373  is installed between two projections  372  which are positioned on the thumb side in the mounted state and between two projections  372  which are positioned on the middle finger in the mounted state. 
     A fourth link portion  308  is provided on the end side of the finger of the third link portion  307 . The fourth link portion  308  is a member of turning with respect to the third base portion  309 . 
     In addition, the fourth link portion  308  includes a linear long length portion  381  and a pair of the projection portions  382  which are projected from the long length portion  381 , and is formed of a plate piece of which an external shape is substantially a T shape. Specifically, a pair of the projection portions  382  are projected in the direction intersecting with the lateral direction of the long length portion  381  from the end portion of the second base portion  505  side of the long length portion  381 , and projected toward the opposite sides. 
     In addition, each of the projection portions  382  includes a hollow portion  821  which is penetrated in a cylindrical shape and a pair of rail portions  373  of the third link portion  307  are respectively inserted into each of the hollow portions  821 . 
     Similar to the first link portion  303  and the second link portion  304  illustrated in  FIG. 8  and  FIG. 9 , since the projection portion  382  slides while being guided by the rail portion  373 , the fourth link portion  308  can relatively approach with respect to and be separated from the second base portion  505  as illustrated in  FIG. 10 . 
     Meanwhile, the total length of the rail portion  373  is sufficiently longer than the total length of the projection portion  382 , for example, it is preferably 1.5 times to 3 times the total length of the projection portion  382 , and more preferably 1.5 times to 2 times. 
     The tip end portion of the long length portion  381  is interposed between a pair of the convex portions  392  of the third base portion  309 . Then, tip end portion of the long length portion  381  and each of the convex portions  392  are connected to each other via a turning support portion  314 . The turning support portion  314  is configured to have an axis which is provided on one of the end portion of the long length portion  381  and each of the convex portions  392  and a bearing which has the axis inserted therein and is provided on the other of the end portion of the long length portion  381  and each of the convex portions  392 . In addition, a turning axis O 314  of the turning support portion  314  is in parallel with the turning axis O 109 . 
     With such a configuration, similar to the third link portion  307 , the third base portion  309  can be turned around the turning axis O 314  which is in parallel with the turning axis O 109  by the turning support portion  314 . Since the turning axis O 313  and the turning axis O 314  are in parallel with the turning axis O 109 , it is possible to easily bend and stretch the proximal interphalangeal joint  109  by the finger joint driving device  501  while preventing unnecessary force from being applied to the proximal interphalangeal joint  109 . 
     Configuration materials of the third link portion  307 , the fourth link portion  308 , and the third base portion  309  are not particularly limited, for example, it is possible to use the same configuration materials as those of the first base portion  302 . In addition, configuration materials of the mounting band  20 C is not particularly limited, for example, it is possible to use the same configuration materials as those of the mounting band  20 A. 
     In addition, as illustrated in  FIG. 10 , the finger joint driving device  501  is further provided with the driving unit (the second driving unit)  306 B in the vicinity of the pair of convex portions  392  of the third base portion  309 . 
     The driving unit  306 B is a mechanical portion which functions for driving the third base portion  309  to be turned via the turning support portion  314 . In addition, the proximal interphalangeal joint  107  and the distal interphalangeal joint  109  of the index finger  101  are separated from each other or synchronized to each other by the driving unit  306 A and the driving unit  306 B, and thus can be reliably turned. Accordingly, since joint portions that assist the user, the operation of the hand becomes easier. 
     Meanwhile, similar to the configuration of the driving unit  306 A, the driving unit  306 B is configured to include, that is, the first rotor  61 , the second rotor  62 , the third rotor  63 , and the piezoelectric motor  64  which causes the third rotor  63  to rotate. Therefore, it is possible to use common components in the configuration components of the driving unit  306 A and the driving unit  306 B, and thus, it is possible to reduce the manufacturing cost of the finger joint driving device  501 . 
     In addition, the driving unit  306 B functions for driving the third base portion  309  to be turned in the embodiment, but may function for driving the third link portion  307  to be turned. 
     As described above, embodiments of the finger joint driving device according to the invention was explained; however, the invention is not limited thereto, each portion configuring the finger joint driving device can be replaced with that of the arbitrary configuration capable of exhibiting the same function. In addition, the arbitrary components may be added to the invention. 
     In addition, the finger joint driving device according to the invention may be a combination of any two or more configurations (features) in the embodiments described above. 
     In addition, the first driving unit can serve of driving the second member (the first link portion) and the third member (the second link portion) to be turned in the first embodiment and the second embodiment, but the first driving unit can also serve of driving the fourth member (the second base portion) to approach with respect to and to be separated from the first member (the first base portion). 
     Further, the first driving unit can serve of driving the second member (the first link portion) and the fourth member (the second base portion) to be turned in the third embodiment and the fourth embodiment, but the first driving unit can also serve of driving the third member (the second link portion) to approach with respect to and to be separated from the first member (the first base portion). 
     In addition, the second driving unit can serve of driving the fifth member (the third link portion) and the sixth member (the fourth link portion) to be turned in the second embodiment, but the second driving unit can also serve of driving the seventh member (the third base portion) to approach with respect to and to be separated from the fourth member (the second base portion). 
     Further, the second driving unit can serve of driving the fifth member (the third link portion) and the seventh member (the third base portion) to be turned in the fourth embodiment, but the second driving unit can also serve of driving the sixth member (the fourth base portion) to approach with respect to and to be separated from the fourth member (the second base portion). 
     The entire disclosures of Japanese Patent Application Nos. 2014-040155, filed Mar. 3, 2014 and 2014-053136, filed Mar. 17, 2014 are expressly incorporated by reference herein.