Coupling Device

Abstract

To provide a joint device capable of expanding and bending an articulated section with power from a power source.SOLUTION: An electrically-driven prosthetic foot 1 includes an under-knee side member 10, an upper-knee side member 20, a knee joint mechanism 30 for connecting them so that an angle formed between the under-knee side member 10 and the upper-knee side member 20 can be changed, and an expansion device 40 capable of changing the angle formed between the under-knee side member 10 and the upper-knee side member 20 by expanding and contracting. The expansion device 40 includes a motor M, and a transmission T for transmitting power of the motor M. The transmission T includes a first transmission mechanism T1 for transmitting power of the motor M at a first transmission gear ratio, and a second transmission mechanism T2 for transmitting power of the motor M at a second transmission gear ratio different from the first transmission gear ratio.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a coupling device. [Background technology]

[0002] Conventionally, as a joint device used in a joint portion that connects two members, one equipped with an extension device capable of changing the angle between the two members is known. One example of such a joint device is a prosthetic leg used in a knee joint. Patent Document 1 describes that a sensor that detects the contraction movement of the muscles of the stump of the amputated leg is provided in the thigh socket of the prosthetic leg that is attached to the stump of the amputated leg, and the throttle of a variable valve of a hydraulic cylinder that adjusts the resistance of bending and extension of the knee joint is controlled by the detection information from the sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-19105 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the prosthetic limb described in Patent Document 1, although it is possible to generate resistance to bending and extension, is not able to generate power for bending and extension.

[0005] The present invention provides a joint device whose articulated portion can be extended and bent by the power of a power source. [Means for solving the problem]

[0006] The first invention is, A first member; A second member; and a connecting portion that connects the first member and the second member in a manner that allows an angle between the first member and the second member to be changed; A joint device including an extension device that can change the angle between the first member and the second member by extending and contracting, The telescopic device is A power source; a power transmission unit that transmits the power of the power source, The power transmission unit includes: a first power transmission path that transmits the power at a first gear ratio; a second power transmission path that transmits the power at a second speed ratio different from the first speed ratio, 、 The telescopic device is a first interrupting mechanism that switches between interruption and connection of power in the first power transmission path; a second interrupting mechanism that switches between interruption and connection of power in the second power transmission path, The coupling device further includes a control unit that controls the first interrupting mechanism and the second interrupting mechanism, The control unit is a connection state in which either one of the first interrupting mechanism or the second interrupting mechanism is connected; a disconnection state in which the first interruption mechanism and the second interruption mechanism are disconnected, .

[0007] The second invention is, A first member; A second member; and a connecting portion that connects the first member and the second member in a manner that allows an angle between the first member and the second member to be changed; A joint device including an extension device that can change the angle between the first member and the second member by extending and contracting, The coupling device is provided to transition between a loaded state in which an external load is applied and a non-loaded state in which no load is applied, The telescopic device is A power source; a power transmission unit that transmits the power of the power source; an interrupting mechanism for switching between interruption and connection of power in the power transmission path; An interruption mechanism control unit for controlling the interruption mechanism, The interrupting mechanism control unit is When in the loaded state, the power supply is controlled to the connected state, and when in the non-loaded state, the power supply is controlled to the disconnected state. Effect of the Invention

[0008] According to the present invention, the connecting portion can be extended and bent via the power transmission portion that transmits the power of the power source. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of an electric prosthetic leg according to a first embodiment of the present invention, as viewed obliquely from the front. [Diagram 2] FIG. 2 is a perspective view of the electric prosthetic leg of FIG. 1, as viewed obliquely from behind. [Diagram 3] FIG. 2 is a diagram showing the internal structure of the electric prosthetic leg of FIG. [Figure 4] FIG. 2 is an enlarged view of a power transmission section of the electric prosthetic leg of FIG. [Figure 5A] 5 is a diagram illustrating power transmission in the power transmission section of FIG. 4 when the power transmission section is in a first speed change state. [Figure 5B] 5 is a diagram illustrating power transmission in the power transmission section of FIG. 4 when the power transmission section is in a second speed change state. FIG. [Figure 5C] 5 is a diagram illustrating power transmission through the power transmission part of FIG. 4 when the power transmission part is in a free state. [Figure 6] 13A and 13B are diagrams illustrating the extension of the knee joint mechanism from a flexed state when climbing stairs. [Figure 7] 13A and 13B are diagrams illustrating bending of a knee joint mechanism from an extended state when climbing stairs. [Figure 8] FIG. 11 is a perspective view of a power transmission section of an electric prosthetic leg according to a second embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view of the power transmission portion of FIG. 8. [Figure 10] 11A and 11B are diagrams illustrating the state of the interrupting mechanism when walking on flat ground. [Figure 11] FIG. 2 is a functional block diagram of a control system for an electric prosthetic limb. [Figure 12] FIG. 1 is a diagram for explaining sensors of an electric prosthetic leg. [Figure 13] FIG. 7 is a diagram for explaining the switching flow of the torque transmission path in FIG. 6 when walking on flat ground. [Figure 14] 7 is a graph showing the load and the like acting on the electric prosthetic leg when walking on flat ground as shown in FIG. 6. [Figure 15] FIG. 15 is an enlarged view of part A in FIG. [Figure 16] FIG. 15 is an enlarged view of part B in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the electric prosthesis as an example of the joint device of the present invention and the control of the electric prosthesis when walking on flat ground will be described with reference to the drawings. In the following description, the front-rear direction, left-right direction, and up-down direction are defined based on the user of the electric prosthesis. In the drawings, the front of the electric prosthesis is indicated as Fr, the rear as Rr, the left side as L, the right side as R, the upper side as U, and the lower side as D.

[0011] First Embodiment [Electric prosthetic limb] The electric prosthetic leg 1 of this embodiment is a prosthetic leg for people without knees, and is attached to one thigh 4 that rotates relatively to the upper body 3 as shown in Fig. 6, and functions as a lower leg 5. As shown in Figs. 1 to 3, the electric prosthetic leg 1 includes a below-knee member 10 located below the knee, an above-knee member 20 located above the knee, a knee joint mechanism 30 that connects the below-knee member 10 and the above-knee member 20 so as to be changeable in angle, and an extension device 40 that can change the angle between the below-knee member 10 and the above-knee member 20 by extending and retracting.

[0012] The above-knee component 20 comprises an upper wall portion 22 provided with an adapter 21 that is connected to a socket not shown, and a pair of upper side wall portions 23 extending downward from both the left and right ends of the upper wall portion 22, and has an approximately U-shape that is open downward when viewed from the front-to-back direction.

[0013] The knee below component 10 comprises a lower wall portion 12 on which the leg portion 11 is provided, and a pair of lower side wall portions 13 extending upward from both the left and right ends of the lower wall portion 12, and has a generally U-shape that is open upward when viewed from the front-to-rear direction.

[0014] Between the pair of upper side walls 23 of the knee-upper member 20, the pair of lower side walls 13 of the knee-lower member 10 are connected rotatably around the rotating parts 35. With this mechanism, the angle between the knee-lower member 10 and the knee-upper member 20 is connected so as to be changeable, and the knee joint mechanism 30 is formed.

[0015] An extension device 40 capable of changing the angle formed between the knee-below member 10 and the knee-below member 20 is provided in the space formed between the knee-below member 20 and the knee-below member 20.

[0016] Referring also to FIG. 4, the telescopic device 40 includes a motor M that outputs rotational power, a transmission T that transmits the power of the motor M, a first spindle unit SP1 that is connected to the transmission T so as to be capable of transmitting power and that converts the rotational power output from the transmission T into translational motion, an interrupting mechanism 50 that is interposed between the motor M and a first speed change mechanism T1 and a second speed change mechanism T2 of the transmission T that will be described later, and a second spindle unit SP2 that converts the rotational power output from the motor M into translational motion of an actuator 55 of the interrupting mechanism 50.

[0017] The transmission T is equipped with a transmission case 60 having a rectangular shape when viewed from the front-rear direction, and including a top plate 61, a bottom plate 62, and a pair of side plate portions 63 connecting the left and right ends of the top plate portion 61 and the bottom plate portion 62. The transmission case 60 has a pair of rotating wings 64 extending downward from the bottom plate portion 62, which are supported by a rotating support wall 14 extending upward from the lower wall portion 12 of the knee below member 10 so as to be swingable but immovable about a lower swing portion 70.

[0018] The motor M is disposed in front of and above the top plate portion 61 of the transmission case 60 so that the output shaft 71 penetrates the top plate portion 61 and protrudes into the inside of the transmission case 60. The first spindle unit SP1 is disposed on the opposite side of the motor M across the interrupting mechanism 50 in the front-to-rear direction. In other words, the motor M is disposed forward of the interrupting mechanism 50 in the front-to-rear direction, and the first spindle unit SP1 is disposed rearward of the interrupting mechanism 50 in the front-to-rear direction. As a result, even if the motor M is mounted on the electric prosthetic leg 1, it is possible to prevent the electric prosthetic leg 1 from becoming large in the width direction while maintaining balance in the front-to-rear direction.

[0019] The second spindle unit SP2, which converts the rotational power output from the motor M into translational motion of the actuator 55 of the interrupter mechanism 50, is disposed between the motor M and the first spindle unit SP1 in the front-rear direction. The output shaft 71 of the motor M, the first spindle 73 of the first spindle unit SP1, and the second spindle 75 of the second spindle unit SP2 are disposed parallel to one another and are disposed so as to face in the up-down direction when the knee joint mechanism 30 is fully extended.

[0020] The first spindle unit SP1 has a first spindle 73 having a male thread 73a and a sleeve 74 having a female thread 74a. The sleeve 74 translates along the axis of the first spindle 73 as the first spindle 73 rotates. In this embodiment, the first spindle 73 receives the rotational power of the motor M transmitted by the transmission T to perform the rotational motion. Meanwhile, the sleeve 74 is attached to a pair of inner side walls 24 extending downward from the upper wall 22 of the knee-upper member 20 so as to be swingable about the upper swing part 25 but immovable. Therefore, when the first spindle 73 rotates to one side (in the direction of the arrow D1 in FIG. 5A) by receiving the rotational power of the motor M transmitted by the transmission T, the sleeve 74 translates away from the transmission T, and when the first spindle 73 rotates to the other side (in the direction of the arrow D2 in FIG. 5B), the sleeve 74 translates toward the transmission T.

[0021] That is, the distance between the sleeve 74 and the transmission T expands or contracts depending on the rotation direction of the first spindle 73. Since the sleeve 74 is immovably attached to the above-knee member 20 as described above, the distance between the sleeve 74 and the transmission T expands or contracts depending on the rotation direction of the first spindle 73, causing the below-knee member 10 to which the transmission T is attached and the above-knee member 20 to which the sleeve 74 is attached to rotate around the rotating part 35. This changes the angle formed between the above-knee member 20 and the below-knee member 10.

[0022] As shown in FIG. 4, the transmission T includes an output gear 72 provided on an output shaft 71 of the motor M, an input gear 77 provided approximately in the center of the second spindle 75 of the second spindle unit SP2 and meshing with the output gear 72, a first transmission mechanism T1, and a second transmission mechanism T2.

[0023] The first transmission mechanism T1 is composed of a first drive gear 78 that is immovably mounted on the upper side of the second spindle 75 of the second spindle unit SP2, and a first driven gear 79 that is mounted on the first spindle 73 of the first spindle unit SP1 so as to rotate integrally with the first spindle 73 and meshes with the first drive gear 78.

[0024] The second transmission mechanism T2 is composed of a second drive gear 80 that is immovably mounted on the underside of the second spindle 75 of the second spindle unit SP2, and a second driven gear 81 that is mounted on the first spindle 73 of the first spindle unit SP1 so as to rotate integrally with the first spindle 73 and meshes with the second drive gear 80.

[0025] The first speed change mechanism T1 transmits the power of the motor M at a first speed change ratio. The second speed change mechanism T2 transmits the power of the motor M at a second speed change ratio different from the first speed change ratio. By providing two power transmission paths with different speed change ratios, it is possible to switch the movement speed and generated power of extension and flexion in the knee joint mechanism 30. As long as the first speed change ratio and the second speed change ratio are different, one of the first speed change mechanism T1 and the second speed change mechanism T2 may be a reduction mechanism and the other an accelerating mechanism, one may be a constant speed mechanism and the other a reduction mechanism or an accelerating mechanism, both may be reduction mechanisms, or both may be accelerating mechanisms.

[0026] When the first gear ratio is defined as the ratio of the post-shift rotation speed, which is the rotation speed on the anti-motor M side (first spindle unit SP1 side) of the first gear change mechanism T1, to the pre-shift rotation speed, which is the rotation speed on the motor M side of the first gear change mechanism T1, and the second gear ratio is defined as the ratio of the post-shift rotation speed, which is the rotation speed on the anti-motor M side (first spindle unit SP1 side) of the second gear change mechanism T2, to the pre-shift rotation speed, which is the rotation speed on the motor M side of the second gear change mechanism T2, it is preferable that the first gear ratio is configured to be smaller than the second gear ratio.

[0027] For example, when the first speed change ratio of the first speed change mechanism T1 is smaller than 1, the rotation speed on the side opposite to the motor M (the first spindle unit SP1 side) decreases compared to the rotation speed on the motor M side, and the torque increases. When the second speed change ratio of the second speed change mechanism T2 is larger than 1, the rotation speed on the side opposite to the motor M (the first spindle unit SP1 side) increases compared to the rotation speed on the motor M side, and the torque decreases. In this case, the first drive gear 78 has a smaller diameter than the second drive gear 80, and the first drive gear 78 and the motor M can be disposed in close proximity to each other. In this embodiment, the first speed change mechanism T1 is disposed closer to the motor M than the second speed change mechanism T2. More specifically, the motor M is disposed in front of the first drive gear 78 so as to overlap the first drive gear 78 in the vertical direction.

[0028] The first speed change mechanism T1 and the second speed change mechanism T2 are switched by an on-off mechanism 50. The on-off mechanism 50 includes an upper clutch 50U that switches between disconnecting and connecting the power in the first speed change mechanism T1, a lower clutch 50D that switches between disconnecting and connecting the power in the second speed change mechanism T2, and an actuator 55 that rotates integrally with the input gear 77.

[0029] The upper clutch 50U is a mesh clutch including a first engaging element 51 on the motor M side and a second engaging element 52 on the first speed change mechanism T1 side. To explain in more detail, the first engaging element 51 is provided above the actuator 55 and the input gear 77 so as to rotate integrally with the input gear 77. The second engaging element 52 is provided below the first driving gear 78 so as to be engageable with the first engaging element 51 and to rotate integrally with the first driving gear 78. The second engaging element 52 and the first driving gear 78 are attached above the second spindle 75 of the second spindle unit SP2 so as to be rotatable relative to the second spindle 75 but immovable.

[0030] The lower clutch 50D is a mesh clutch including a third engaging element 53 which is an engaging element on the motor M side, and a fourth engaging element 54 which is an engaging element on the second speed change mechanism T2 side. To explain in more detail, the third engaging element 53 is provided below the actuator 55 and the input gear 77 so as to rotate integrally with the input gear 77. The fourth engaging element 54 is provided above the second driving gear 80 so as to be engageable with the third engaging element 53 and to rotate integrally with the second driving gear 80. The fourth engaging element 54 and the second driving gear 80 are attached below the second spindle 75 of the second spindle unit SP2 so as to be rotatable relative to the second spindle 75 but immovable.

[0031] As described above, the actuator 55 is attached to the input gear 77 so as to rotate integrally with the input gear 77, and the first engaging element 51 and the third engaging element 53 are attached to the upper and lower parts of the actuator 55 so as to rotate integrally with the input gear 77. The actuator 55 is disposed approximately at the center of the second spindle 75, that is, between the first driving gear 78 and the second driving gear 80 in the vertical direction. Here, the actuator 55 is the screw nut 76 of the second spindle unit SP2. The second spindle unit SP2 has the second spindle 75 having a male thread and the screw nut 76 (actuator 55) having a female thread, and as the input gear 77 rotates, the screw nut 76 (actuator 55) translates while rotating along the axis of the second spindle 75.

[0032] The screw nut 76 (operating element 55) moves upward in the vertical direction, which is the movement direction of the translational motion, when the motor M rotates in a first direction (the direction of the arrow D1 in FIG. 5A), and moves downward in the vertical direction when the motor M rotates in a second direction (the direction of the arrow D2 in FIG. 5B) opposite to the first direction. In this way, by changing the rotation direction of the motor M, the movement direction of the operating element 55 can be changed.

[0033] The interrupter mechanism 50 can be in three states, a first speed-changing state, a second speed-changing state, and a free state, by the translational movement of the actuator 55 along the axis of the second spindle 75.

[0034] In the first speed change state, as shown in Fig. 5A, the motor M rotates in the first direction (the direction of the arrow D1 in Fig. 5A) and the screw nut 76 (the actuator 55) moves upward, so that the first engaging element 51 and the second engaging element 52 are in an engaged state and the third engaging element 53 and the fourth engaging element 54 are in a disengaged state. In other words, the upper clutch 50U is in an engaged state and the lower clutch 50D is in a disengaged state. In the first speed change state, the power of the motor M is transmitted to the output gear 72, the input gear 77, the actuator 55, the first engaging element 51, the second engaging element 52, the first driving gear 78, the first driven gear 79, and the first spindle unit SP1.

[0035] In the second speed change state, as shown in Fig. 5B, the motor M rotates in the second direction (the direction of the arrow D2 in Fig. 5B) and the screw nut 76 (the actuator 55) moves downward, so that the first engaging element 51 and the second engaging element 52 are in a disengaged state and the third engaging element 53 and the fourth engaging element 54 are in a connected state. In other words, the upper clutch 50U is in a disengaged state and the lower clutch 50D is in a connected state. In the second speed change state, the power of the motor M is transmitted to the output gear 72, the input gear 77, the actuator 55, the third engaging element 53, the fourth engaging element 54, the second driving gear 80, the second driven gear 81, and the first spindle unit SP1.

[0036] In the free state, as shown in FIG. 5C, the first engaging element 51 and the second engaging element 52 are in a disconnected state, and the third engaging element 53 and the fourth engaging element 54 are in a disconnected state. In other words, the upper clutch 50U and the lower clutch 50D are both in a disconnected state. In the free state, the motor M is stopped, and the first driven gear 79 and the second driven gear 81 rotate due to the rotation of the first spindle unit SP1. However, the rotation of the first spindle unit SP1 is transmitted to the first driven gear 79, the first driving gear 78, and the second engaging element 52, but is not transmitted to the first engaging element 51. Similarly, the rotation of the first spindle unit SP1 is transmitted to the second driven gear 81, the second driving gear 80, and the fourth engaging element 54, but is not transmitted to the third engaging element 53.

[0037] That is, in the first and second shifting states, either the upper clutch 50U or the lower clutch 50D of the on-off mechanism 50 is in a connected state, and in the free state, the upper clutch 50U and the lower clutch 50D of the on-off mechanism 50 are in a disconnected state. Hereinafter, the first and second shifting states may be referred to as the connected states of the on-off mechanism 50, and the free state may be referred to as the disconnected state of the on-off mechanism 50.

[0038] 4 to 5C, the reference symbol D denotes a rotary damper, which provides an appropriate resistance to the second spindle 75 of the second spindle unit SP2 so that the screw nut 76 (operating element 55) can reliably move in a translational direction when the motor M rotates. The rotary damper D is composed of a first damper gear 86 provided on a rotating shaft of the rotary damper D, and a second damper gear 87 provided on the second spindle 75 of the second spindle unit SP2 so as to rotate integrally with the second spindle 75 and meshing with the first damper gear 86. The rotary damper D is disposed in front of and above the bottom plate portion 62 of the transmission case 60, and below the motor M.

[0039] With the electric prosthetic leg 1 configured in this manner, it is possible to smoothly ascend stairs, whereas with a passive prosthetic leg equipped with a previous passive damper, it was necessary to ascend one step at a time with the non-prosthetic leg (healthy leg).

[0040] Specifically, as shown in FIG. 6, when the electric prosthetic leg 1 is put forward to climb stairs and weight is applied from the outside to the electric prosthetic leg 1, a large force is required to extend the knee joint mechanism 30 from a bent position.

[0041] At this time, as shown in Fig. 5A, by rotating the motor M in a first direction (the direction of the arrow D1 in Fig. 5A), the power of the motor M is transmitted from the output gear 72 to the input gear 77. By rotating the input gear 77 in a second direction (the direction of the arrow D2 in Fig. 5A), the actuator 55 moves upward while being guided by the second spindle 75 while rotating around the second spindle 75 of the second spindle unit SP2. Then, the first engagement element 51 provided above the actuator 55 and the input gear 77 engages with the second engagement element 52 provided below the first drive gear 78, and the interrupter mechanism 50 enters the first speed change state.

[0042] When the interrupter mechanism 50 is in the first speed change state, the power of the motor M is transmitted to the output gear 72, the input gear 77, the actuator 55, the first engagement element 51, the second engagement element 52, the first drive gear 78, the first driven gear 79, and the first spindle unit SP1. The first drive gear 78 rotates together with the input gear 77 in the second direction (the direction of the arrow D2 in FIG. 5A), causing the first driven gear 79 to rotate in the first direction (the direction of the arrow D1 in FIG. 5A), and the first driven gear 79 rotates in the first direction (the direction of the arrow D1 in FIG. 5A), causing the first spindle 73 of the first spindle unit SP1 to rotate in the first direction (the direction of the arrow D1 in FIG. 5A). As a result, the sleeve 74 moves in a translational manner away from the transmission T, and the upper-knee member 20 to which the sleeve 74 is attached rotates about the rotating part 35 relative to the lower-knee member 10 to which the transmission T is attached, thereby extending the knee joint mechanism 30.

[0043] On the other hand, in order to smoothly ascend stairs, it is necessary to bend (lift) the knee joint mechanism 30 from an extended state with weight being applied to the healthy leg, in other words, with no external weight being applied to the electric prosthetic leg 1, as shown in Fig. 7. When bending the knee joint mechanism 30 from an extended state, a large power is not required, but a quick movement is required.

[0044] At this time, as shown in Fig. 5B, by rotating the motor M in the second direction (the direction of the arrow D2 in Fig. 5B), the power of the motor M is transmitted from the output gear 72 to the input gear 77. By rotating the input gear 77 in the first direction (the direction of the arrow D1 in Fig. 5B), the actuator 55 moves downward while being guided by the second spindle 75 while rotating around the second spindle 75 of the second spindle unit SP2. Then, the third actuator 53 provided below the actuator 55 and the input gear 77 engages with the fourth actuator 54 provided above the second drive gear 80, and the interrupter mechanism 50 enters the second speed change state.

[0045] When the interrupter mechanism 50 is in the second speed change state, the power of the motor M is transmitted to the output gear 72, the input gear 77, the actuator 55, the third engager 53, the fourth engager 54, the second drive gear 80, the second driven gear 81, and the first spindle unit SP1. The second drive gear 80 rotates together with the input gear 77 in the first direction (the direction of the arrow D1 in FIG. 5B), causing the second driven gear 81 to rotate in the second direction (the direction of the arrow D2 in FIG. 5B), and the second driven gear 81 rotates in the second direction (the direction of the arrow D2 in FIG. 5B), causing the first spindle 73 of the first spindle unit SP1 to rotate in the second direction (the direction of the arrow D2 in FIG. 5B). As a result, the sleeve 74 moves in translation so as to approach the transmission T, and the knee-below member 10 to which the transmission T is attached rotates about the rotating part 35 relative to the knee-above member 20 to which the sleeve 74 is attached, thereby bending the knee joint mechanism 30.

[0046] In the electric prosthetic leg 1 configured in this manner, the knee joint mechanism 30 can be extended and bent via a transmission T that transmits the power of the motor M. The rotation range of the knee joint mechanism 30 is limited to 180° or less, and when the knee joint mechanism 30 is extended, the angle between the lower-knee member 10 and the upper-knee member 20 is approximately 180°, and when the knee joint mechanism 30 is bent, this angle is less than 180°.

[0047] The transmission T has two power transmission paths with different gear ratios, and therefore can switch between the extension and flexion movement speeds and the generated power of the knee joint mechanism 30. In particular, when climbing stairs, the required movement speed and generated power differ between when the knee joint mechanism 30 is flexed and when it is extended, and the power transmission path can be changed between when the knee joint mechanism 30 is flexed and when it is extended.

[0048] In addition, the on-off mechanism 50 interposed between the motor M and the transmission T has an upper clutch 50U interposed between the motor M and the first transmission mechanism T1, and a lower clutch 50D interposed between the motor M and the second transmission mechanism T2, so that the two power transmission paths can be appropriately switched.

[0049] In particular, the telescopic device 40 includes a second spindle unit SP2 that converts the rotational power output from the motor M into translational motion of the actuator 55, so that a single motor M can control the actuator 55 and the extension and flexion of the knee joint mechanism 30. Furthermore, the single actuator 55 is configured to be able to switch the transmission T between the first speed change state, the second speed change state, and a free state, so that it is possible to avoid two power transmission paths being connected simultaneously.

[0050] When descending stairs or walking on flat ground, the power of motor M is not required, so motor M is stopped. In the following explanation, a leg that is not weighted from the outside, in other words, a leg that is not supporting the body weight, is referred to as a swing leg, and a leg that is weighted from the outside, in other words, a leg that is supporting the body weight, is referred to as a standing leg. Note that the weight of gravity of the electric prosthetic leg 1 is always acting on the electric prosthetic leg 1 (its own weight), but its own weight is not included in the weight from the outside.

[0051] When an external load is applied to the electric prosthetic leg 1 with the motor M stopped, the knee joint mechanism 30 in the extended state may bend due to being unable to withstand the load, which may result in so-called knee bending. Therefore, when descending stairs or walking on flat ground, in order to prevent the user from unintentionally bending the knee, the disconnecting mechanism 50 is maintained in a connected state when an external load is applied to the electric prosthetic leg 1 (standing leg). On the other hand, in a state in which no external load is applied to the electric prosthetic leg 1 (free leg), the disconnecting mechanism 50 is maintained in a disconnected state, making it possible to smoothly extend the knee joint mechanism 30 from a bent state.

[0052] FIG. 10 is a diagram for explaining the state of the interrupting mechanism 50 when walking on flat ground. That is, when walking on flat ground, in a load state where the electric prosthetic leg 1 is loaded from the outside (I-leg stance in FIG. 10), the motor M is stopped and the on-off mechanism 50 is maintained in a connected state. The on-off mechanism 50 may be in a first speed change state in which the upper clutch 50U is in a connected state and the lower clutch 50D is in a disconnected state, or in a second speed change state in which the upper clutch 50U is in a disconnected state and the lower clutch 50D is in a connected state. The second speed change state is preferable.

[0053] On the other hand, when walking on flat ground, in a non-loaded state where no weight is applied from the outside to the electric prosthetic leg 1 (III free leg in FIG. 10), the motor M is stopped and the on-off mechanism 50 is maintained in a free state where both the upper clutch 50U and the lower clutch 50D are in a disconnected state. The control of switching the on-off mechanism 50 from the connected state to the disconnected state when walking on flat ground (II taking off from the ground in FIG. 10) and switching the on-off mechanism 50 from the disconnected state to the connected state (IV immediately before landing in FIG. 10) (hereinafter, flat ground walking control) will be described later.

[0054] <Second embodiment> The electric prosthetic leg 1 of the second embodiment differs from the electric prosthetic leg 1 of the first embodiment in the configuration of the telescopic device 40. More specifically, in the telescopic device 40 of the first embodiment, the translational motion of the actuator 55 is realized by converting the rotational power output from the motor M by the second spindle unit SP2. In contrast, in the telescopic device 40 of the second embodiment, the translational motion of the actuator 55 is realized by a clutch actuator ACT, which is a drive source different from the motor M, and a clutch fork 90 that transmits the power of the clutch actuator ACT to the actuator 55. In the following description, the telescopic device 40 of the electric prosthetic leg 1 of the second embodiment will be described with reference to Figs. 8 and 9, but the same or equivalent configurations as those of the electric prosthetic leg 1 of the first embodiment will be denoted by the same reference numerals in the drawings, and description will be omitted, and only the differences will be described.

[0055] As shown in FIGS. 8 and 9, the telescopic device 40 of the second embodiment includes a motor M that outputs rotational power, a transmission T that transmits the power of the motor M, a first spindle unit SP1 that is connected to the transmission T so as to be capable of transmitting power and that converts the rotational power output from the transmission T into translational motion, an interrupting mechanism 50 that is interposed between the motor M and the first speed change mechanism T1 and the second speed change mechanism T2 of the transmission T, a support shaft 95 that is arranged in parallel to the output shaft 71 of the motor M and the first spindle 73 of the first spindle unit SP1 and supports the interrupting mechanism 50, a clutch actuator ACT that performs translational motion, and a clutch fork 90 that transmits the power of the clutch actuator ACT to an actuator 55 of the interrupting mechanism 50.

[0056] The clutch actuator ACT is a power source different from the motor M, and performs translational motion along the axial direction (vertical direction) of the support shaft 95 as indicated by an arrow Y1 in FIG.

[0057] One end of the clutch fork 90 is connected to the clutch actuator ACT, and an intermediate portion is supported by the pivot shaft 65, so that the clutch fork 90 can pivot about the pivot shaft 65 as shown by the arrow Y2 in Fig. 8. The other end of the clutch fork 90 is provided with arms 92 that branch into two from a branch portion 91 located on the opposite side of the pivot shaft 65 from the clutch actuator ACT, and extend in opposite directions in an arc shape. A connecting pin 93 that fits into the slide clutch 56, which will be described later, is provided at the tip of each arm 92. Therefore, as the clutch actuator ACT performs translational motion, the clutch fork 90 pivots about the pivot shaft 65, and the connecting pin 93 of the clutch fork 90 pivots up and down.

[0058] The transmission T includes an output gear 72 provided on an output shaft 71 of the motor M, a first input gear 77A and a second input gear 77B provided in the approximate center of the support shaft 95 and meshing with the output gear 72, a first transmission mechanism T1, and a second transmission mechanism T2. The first input gear 77A and the second input gear 77B constitute an input gear 77.

[0059] The first transmission mechanism T1 is composed of a first drive gear 78 that is immovably mounted on the upper side of the support shaft 95, and a first driven gear 79 that is mounted on the first spindle 73 of the first spindle unit SP1 so as to rotate integrally with the first spindle 73 and meshes with the first drive gear 78.

[0060] The second transmission mechanism T2 is composed of a second drive gear 80 that is immovably mounted on the underside of the support shaft 95, and a second driven gear 81 that is mounted on the first spindle 73 of the first spindle unit SP1 so as to rotate integrally with the first spindle 73 and meshes with the second drive gear 80.

[0061] The speed ratios of the first and second speed change mechanisms T1 and T2 are the same as those in the first embodiment, and therefore will not be described here. The first and second speed change mechanisms T1 and T2 are switched by an on-off mechanism 50. The on-off mechanism 50 includes an upper clutch 50U interposed between the motor M and the first speed change mechanism T1, a lower clutch 50D interposed between the motor M and the second speed change mechanism T2, and an actuator 55.

[0062] The upper clutch 50U is a mesh clutch including a first engaging element 51 on the motor M side and a second engaging element 52 on the first speed change mechanism T1 side. To explain in more detail, the first engaging element 51 is provided above the first input gear 77A so as to rotate integrally with the first input gear 77A. The second engaging element 52 is provided below the first driving gear 78 so as to be engageable with the first engaging element 51 and to rotate integrally with the first driving gear 78. The second engaging element 52 and the first driving gear 78 are attached above the support shaft 95 so as to be rotatable relative to the support shaft 95 but immovable.

[0063] The lower clutch 50D is a mesh clutch including a third engaging element 53 which is an engaging element on the motor M side, and a fourth engaging element 54 which is an engaging element on the second speed change mechanism T2 side. To explain in more detail, the third engaging element 53 is provided below the second input gear 77B so as to rotate integrally with the second input gear 77B. The fourth engaging element 54 is provided above the second driving gear 80 so as to be engageable with the third engaging element 53 so as to rotate integrally with the second driving gear 80. The fourth engaging element 54 and the second driving gear 80 are attached below the support shaft 95 so as to be rotatable relative to the support shaft 95 but immovable.

[0064] The actuator 55 includes an annular slide clutch 56 that is constantly engaged with the connecting pin 93 of the clutch fork 90, and a bearing 57 that performs translational motion together with the slide clutch 56, and is disposed between the first input gear 77A and the second input gear 77B in the vertical direction.

[0065] The slide clutch 56 is provided with a connecting hole with which the connecting pin 93 of the clutch fork 90 engages, and the connecting hole absorbs the rocking motion of the clutch fork 90 and converts it into a translational motion of the slide clutch 56 in the up and down direction.

[0066] The bearing 57 comprises an outer ring 57a supported non-rotatably on the slide clutch 56, an inner ring 57b configured to rotate integrally with a first input gear 77A provided with a first engaging element 51 and a second input gear 77B provided with a third engaging element 53, and a rolling body 57c disposed between the outer ring 57a and the inner ring 57b to allow relative rotation between the outer ring 57a and the inner ring 57b.

[0067] The inner ring 57b is supported on the outer periphery of a support flange 96 that is connected to a support shaft 95 by a key together with the first input gear 77A and the second input gear 77B so as to be capable of translational movement in the vertical direction.

[0068] The slide clutch 56 and the bearing 57 (operator 55) move upward along the support shaft 95 when one end of the clutch fork 90 moves downward by the clutch actuator ACT, and move downward along the support shaft 95 when one end of the clutch fork 90 moves upward by the clutch actuator ACT. A predetermined gap is provided between the slide clutch 56 and the outer ring 57a and the first input gear 77A in the vertical direction, so that the first input gear 77A does not interfere with the slide clutch 56 and the outer ring 57a, which are non-rotating members. Similarly, a predetermined gap is provided between the slide clutch 56 and the outer ring 57a and the second input gear 77B in the vertical direction, so that the second input gear 77B does not interfere with the slide clutch 56 and the outer ring 57a, which are non-rotating members.

[0069] The on-off mechanism 50 can be in three states: a first speed change state, a second speed change state, and a free state, by the translational movement of the slide clutch 56 and the bearing 57 (operating element 55) in the vertical direction along the axis of the support shaft 95.

[0070] In the first speed change state, the slide clutch 56 and the bearing 57 (the actuator 55) move upward, so that the first engaging element 51 and the second engaging element 52 are in an engaged state and the third engaging element 53 and the fourth engaging element 54 are in a disengaged state, as in Fig. 5A. In other words, the upper clutch 50U is engaged and the lower clutch 50D is disengaged. In the first speed change state, the power of the motor M is transmitted to the output gear 72, the first input gear 77A (the inner wheel 57b and the second input gear 77B), the first engaging element 51, the second engaging element 52, the first driving gear 78, the first driven gear 79, and the first spindle unit SP1.

[0071] In the second speed change state, the slide clutch 56 and the bearing 57 (operator 55) move downward, so that the first engaging element 51 and the second engaging element 52 are disengaged and the third engaging element 53 and the fourth engaging element 54 are engaged, as in Fig. 5B. In other words, the upper clutch 50U is disengaged and the lower clutch 50D is engaged. In the second speed change state, the power of the motor M is transmitted to the output gear 72, the second input gear 77B (the inner wheel 57b and the first input gear 77A), the third engaging element 53, the fourth engaging element 54, the second driving gear 80, the second driven gear 81, and the first spindle unit SP1.

[0072] In the free state, the first engaging element 51 and the second engaging element 52 are in a disconnected state, and the third engaging element 53 and the fourth engaging element 54 are in a disconnected state, as in FIG. 5C. In other words, the upper clutch 50U is disconnected, and the lower clutch 50D is disconnected. In the free state, the motor M is stopped, and the first driven gear 79 and the second driven gear 81 rotate due to the rotation of the first spindle unit SP1. However, the rotation of the first spindle unit SP1 is transmitted to the first driven gear 79, the first driving gear 78, and the second engaging element 52, but is not transmitted to the first engaging element 51. Similarly, the rotation of the first spindle unit SP1 is transmitted to the second driven gear 81, the second driving gear 80, and the fourth engaging element 54, but is not transmitted to the third engaging element 53.

[0073] In the electric prosthetic leg 1 configured in this manner, similarly to the first embodiment, the knee joint mechanism 30 can be extended and bent via the transmission T that transmits the power of the motor M, and the effects described in the electric prosthetic leg 1 of the first embodiment can be obtained. In addition, in the electric prosthetic leg 1 of the second embodiment, the actuator 55 is switched using the clutch actuator ACT, which is a power source different from the motor M for extending and bending the knee joint mechanism 30, so that the actuator 55 can be switched more stably.

[0074] <Level walking control> Next, flat ground walking control using the electric prosthetic leg 1 of the first embodiment and the second embodiment described above will be described by taking the electric prosthetic leg 1 of the second embodiment as an example.

[0075] As shown in Figures 11 and 12, the electric prosthetic leg 1 is provided with a load sensor, a load / unload sensor 201, provided on the lower part of the knee lower member 10 (e.g., the leg 11), a shin IMU (Inertial Measurement Unit) 203, which is a posture sensor provided on the knee lower member 10 and capable of detecting the angle (ground angle) of the knee lower member 10 with respect to the ground, and a knee angle sensor 205, which is a rotational angle sensor that detects the angle formed between the knee lower member 10 and the knee upper member 20.

[0076] The control system 100 of the electric prosthetic leg 1 includes a load / unload acquisition unit 102 that acquires a load FZ applied to the knee lower member 10, a load transition acquisition unit 113 that acquires the transition of the electric prosthetic leg 1 from an unloaded state to a loaded state, an unloaded transition acquisition unit 114 that acquires the transition of the electric prosthetic leg 1 from a loaded state to an unloaded state, a knee angle acquisition unit 103 that acquires a knee angle θ that is the angle between a center line CL5 of the lower leg 5 and a center line CL4 of the thigh 4, and a vertical line LN1 that extends vertically through the rotating unit 35 of the knee joint mechanism 30. The apparatus includes a lower leg angle calculation unit 107 that calculates a lower leg angle α, which is the angle of the lower leg 5 relative to the hip joint 6, a lower leg angular velocity calculation unit 111 that calculates a lower leg angular velocity, which is the angular velocity of the lower leg angle α, a lower leg angular acceleration calculation unit 112 that calculates a lower leg angular acceleration, which is the angular acceleration of the lower leg angle α, a thigh angle calculation unit 106 that calculates a thigh angle β, which is the angle of the thigh 4 with respect to a vertical line LN2 that passes through the hip joint 6 and extends in the vertical direction, a motor control unit 108 that controls the motor M, and an interruption mechanism control unit 110 that controls the state of the interruption mechanism 50. Note that in the first embodiment, the motor control unit 108 also serves as the interruption mechanism control unit 110.

[0077] The load / unload acquisition unit 102 acquires a load FZ, which is an axial force applied to the knee below member 10, from the load / unload sensor 201. The load FZ applied to the knee below member 10 may be a detected value of the load / unload sensor 201 or a predicted value. In this embodiment, the load FZ applied to the knee below member 10 in the tensile direction is regarded as a positive direction.

[0078] The knee angle acquisition unit 103 acquires the knee angle θ by subtracting the angle detected by the knee angle sensor 205 from 180°. The knee angle θ is set to 0° when the center line CL5 of the lower leg 5 and the center line CL4 of the thigh 4 coincide with each other, and increases in the positive direction as the knee joint mechanism 30 bends.

[0079] The crus angle calculation unit 107 acquires the crus angle α based on the ground angle of the crus 5 obtained by the shin IMU 203. The crus angle α is a positive value when the crus 5 is behind the vertical line LN1 that passes through the rotating unit 35 of the knee joint mechanism 30 and extends vertically, and is a negative value when the crus 5 is ahead of the vertical line LN1. In the following description, the inclination in which the upper end of the crus 5 is located ahead of the lower end of the crus 5 is referred to as the forward inclination state of the crus 5, and the inclination in which the upper end of the crus 5 is located behind the lower end of the crus 5 is referred to as the backward inclination state of the crus 5. Therefore, when the crus 5 is in the forward inclination state, the crus angle α is a positive value, and when the crus 5 is in the backward inclination state, the crus angle α is a negative value.

[0080] The lower leg angular velocity calculation unit 111 calculates the lower leg angular velocity, which is the amount of change per unit time of the lower leg angle α acquired by the lower leg angle calculation unit 107.

[0081] The lower leg angular acceleration calculation unit 112 calculates the lower leg angular acceleration, which is the amount of change per unit time of the lower leg angular velocity calculated by the lower leg angular velocity calculation unit 111.

[0082] The thigh angle calculation unit 106 calculates the thigh angle β based on the ground angle of the lower leg 5 obtained by the shin IMU 203 and the knee angle θ by the knee angle sensor 205. The thigh angle β is a positive value when the thigh 4 is behind the vertical line LN2, and is a negative value when the thigh 4 is ahead of the virtual line LN. In the following description, the inclination in which the upper end of the thigh 4 is located ahead of the lower end of the thigh 4 is referred to as the forward inclination state of the thigh 4, and the inclination in which the upper end of the thigh 4 is located behind the lower end of the thigh 4 is referred to as the backward inclination state of the thigh 4. Therefore, the thigh angle β when the thigh 4 is in the forward inclination state is a positive value, and the thigh angle β when the thigh 4 is in the backward inclination state is a negative value.

[0083] The motor control unit 108 controls the drive / stop of the motor M and the output when the motor M is driven. When walking on flat ground, the motor control unit 108 stops the motor M as described above.

[0084] During walking on flat ground, as described above, when the electric prosthetic leg 1 is in a weight-bearing state (standing leg), the on-off mechanism control unit 110 controls the on-off mechanism 50 to a connected state, and when the electric prosthetic leg 1 is in an unweighted state (swing leg), the on-off mechanism control unit 110 controls the on-off mechanism 50 to a disconnected state. In addition, the on-off mechanism control unit 110 switches the on-off mechanism 50 from a disconnected state to a connected state when the weighted transition acquisition unit 113 acquires a transition from an unweighted state to a weighted state, and switches the on-off mechanism 50 from a connected state to a disconnected state when the unweighted transition acquisition unit 114 acquires a transition from a weighted state to an unweighted state.

[0085] If the weighted transition acquisition unit 113 does not appropriately determine the transition from the unweighted state to the weighted state, mechanical elements will come into contact with each other inside the extension device 40 when the swing leg of the electric prosthetic leg 1 ends, causing abnormal noise. On the other hand, if the unweighted transition acquisition unit 114 does not appropriately determine the transition from the weighted state to the unweighted state, the toes of the electric prosthetic leg 1, which cannot freely bend its ankle like a healthy leg, will get stuck on the ground when the stance leg ends. This transition determination will be specifically described below with reference to Figs. 13 to 16.

[0086] Fig. 14 is a graph showing the load FZ, knee angle θ, lower leg angle α, lower leg angular velocity, and thigh angle β acting on the electric prosthetic leg 1 when walking on flat ground, and the thick solid lines in Fig. 14 indicate switching between the connected state and the disconnected state of the on-off mechanism 50. Fig. 15 is an enlarged view of part A in Fig. 14, and Fig. 16 is an enlarged view of part B in Fig. 14.

[0087] [Swinging leg_Transition condition to connected state] First, the conditions for transition to the connected state when the electric prosthetic leg 1 is in the swing leg state will be described with reference to Figs.

[0088] (First connection condition_P1) Knee angle θ<θth

[0089] θth(°) is a threshold value for preventing contact between mechanical elements when the knee is in a state immediately before extension, and is, for example, 0° to 10°. The weighted transition acquisition unit 113 determines the transition from the unweighted state to the weighted state based on the knee angle θ, thereby preventing the knee angle θ from exceeding the threshold θth and causing the knee joint mechanism 30 to extend. This makes it possible to prevent contact between mechanical elements, and suppresses the generation of abnormal noise during the transition.

[0090] (Second connection condition_P2) FZ>Fth where Fth<0(N)

[0091] Fth(N) is a threshold value for determining that the lower leg 5 (electric prosthetic leg 1) is a free leg. The load transition acquisition unit 113 determines the transition from the unloaded state to the loaded state based on the load FZ applied to the knee lower member 10, thereby verifying that the estimation that the electric prosthetic leg 1 is a free leg under the first connection condition is correct, and the estimation accuracy of the transition from the unloaded state to the loaded state can be improved.

[0092] (Third connection condition_P3) Lower leg angular velocity <ωth1 However, ωth1(deg / s)<0

[0093] ωth1 (deg / s) is a threshold value for determining that the lower leg 5 (electric prosthetic leg 1) is rotating in a backward tilt direction. The weighted transition acquisition unit 113 determines the transition from the unweighted state to the weighted state based on the angular velocity of the lower leg angle α (lower leg angular velocity), thereby making it possible to detect the moment immediately before the swing leg of the electric prosthetic leg 1 ends, and to improve the estimation accuracy of the transition from the unweighted state to the weighted state.

[0094] When the first connection condition is satisfied, preferably when at least one of the second connection condition and the third connection condition in addition to the first connection condition is satisfied, and more preferably when all of the first connection condition to the third connection condition are satisfied, the weighted transition acquisition unit 113 determines that there is a transition from the non-weighted state to the weighted state, and the interrupter mechanism control unit 110 switches the interrupter mechanism 50 from the disconnected state to the connected state.

[0095] Based on these conditions, the load transition acquisition unit 113 determines that there is a transition from a non-loaded state to a loaded state, and the interrupter mechanism control unit 110 switches the interrupter mechanism 50 from a disconnected state to a connected state, thereby allowing the electric prosthetic leg 1 to smoothly transition from the swing leg to the stance leg just before the swing leg ends (just before the stance leg begins), preventing the generation of abnormal noise due to contact between mechanical elements during the transition.

[0096] [Stance_Transition condition to the blocked state] Next, the conditions for transitioning to the disconnected state when the electrically powered prosthetic leg 1 is in a standing leg will be described with reference to Figs.

[0097] (First cutoff condition_Q1) Lower leg angular velocity>ωth2 However, ωth2(deg / s)>0

[0098] ωth2 (deg / s) is a threshold value for determining whether the lower leg 5 is tilted forward. That is, the non-weighted transition acquisition unit 114 determines the transition from the weighted state to the non-weighted state based on the lower leg angular velocity of the lower leg 5.

[0099] (Second cutoff condition_Q2) Lower leg angular acceleration>αth where αth(deg / s 2 )>0

[0100] αth(deg / s 2 ) indicates that the forward lean of the lower leg 5 is accelerating. That is, the non-weighted transition acquisition unit 114 determines the transition from a weighted state to an unweighted state based on the lower leg angular acceleration of the lower leg 5. The first cut-off condition and the second cut-off condition make it possible to detect the state immediately before the end of the stance leg (immediately before the swing leg starts), and to prevent the toe from catching on the ground when transitioning to the swing leg.

[0101] (Third cutoff condition_Q3) Fz≦Fth where Fth<0(N)

[0102] Fth is the same value as the threshold value of the second connection condition described above, and is the threshold value for determining that the lower leg 5 (electric prosthetic leg 1) is a standing leg here. The threshold value of this third cut-off condition may be a value different from the threshold value of the second connection condition. The non-weighted transition acquisition unit 114 determines the transition from the weighted state to the non-weighted state based on the weight FZ applied to the knee below member 10, and can verify that the estimation that the electric prosthetic leg 1 is a standing leg under the first cut-off condition and the second cut-off condition is correct, thereby improving the estimation accuracy of the transition from the non-weighted state to the weighted state.

[0103] (Fourth cutoff condition_Q4) Thigh angle β>0°

[0104] The fourth cutoff condition is a condition for determining that the lower leg 5 (electric prosthetic leg 1) is tilted forward. The non-weighted transition acquisition unit 114 determines the transition from the weighted state to the non-weighted state based on the thigh angle β. This allows for more appropriate determination immediately before the end of the stance leg (immediately before the start of the swing leg), and improves the estimation accuracy of the transition from the weighted state to the non-weighted state.

[0105] The non-weighted transition acquisition unit 114 determines that there is a transition from the weighted state to the non-weighted state when the first cut-off condition and the second cut-off condition are satisfied, preferably when at least one of the third cut-off condition and the fourth cut-off condition are also satisfied, and more preferably when both the third cut-off condition and the fourth cut-off condition are also satisfied, and the interrupter mechanism control unit 110 switches the interrupter mechanism 50 from the connected state to the cut-off state.

[0106] Based on these conditions, the non-weighted transition acquisition unit 114 determines that there is a transition from a weighted state to an unweighted state, and the interrupter mechanism control unit 110 switches the interrupter mechanism 50 from a connected state to a disconnected state, thereby allowing the electric prosthetic leg 1 to smoothly transition from the standing leg to the swing leg just before the standing leg ends (just before the swing leg starts), and preventing the toes from catching on the ground during the transition.

[0107] The present invention is not limited to the above-described embodiment, and modifications and improvements are possible as appropriate. For example, in the above embodiment, an electric prosthetic leg was given as an example of one embodiment of the joint device of the present invention, but this is not limited to this and it may also be applied to the upper limb (arm joint), and the subject wearing it may be an animal other than a human, or even a robot.

[0108] In addition, in the above embodiment, the power of one motor M is configured to be transmitted to the first speed change mechanism T1 and the second speed change mechanism T2 via the interrupting mechanism 50, but this is not limited to the above, and an interrupting mechanism may be provided between each of the two power sources and the first speed change mechanism T1 and the second speed change mechanism T2.

[0109] Furthermore, it is not necessary that both the first speed change mechanism T1 and the second speed change mechanism T2 are provided, and it is sufficient that only one of them is provided.

[0110] Furthermore, the on-off mechanism 50 is not limited to a dog clutch, but may be another clutch mechanism such as a friction clutch or a centrifugal clutch, or may be a clutchless mechanism such as a continuous gear ratio change mechanism.

[0111] This specification also describes at least the following items. Note that, in parentheses, components corresponding to those in the above-mentioned embodiment are shown, but the present invention is not limited to these.

[0112] (1) a first member (knee-lower member 10); A second member (above-knee member 20), a joint portion (knee joint mechanism 30) that connects the first member and the second member in a manner that allows the angle between the first member and the second member to be changed; A joint device (electric prosthetic leg 1) including an extension device (extension device 40) that can change the angle between the first member and the second member by extending and contracting, The telescopic device is A power source (motor M), A power transmission unit (transmission T) that transmits the power of the power source, The power transmission unit includes: a first power transmission path (first speed change mechanism T1) that transmits the power at a first speed change ratio; a second power transmission path (second speed change mechanism T2) that transmits the power at a second speed change ratio different from the first speed change ratio, the coupling device comprising:

[0113] According to (1), the connecting part can be extended and bent via the power transmission part that transmits the power of the power source. In addition, since the power transmission part has two power transmission paths with different gear ratios, the operating speed of the extending and bending at the connecting part and the generated power can be switched.

[0114] (2) A coupling device according to (1), The telescopic device is a first connecting / disconnecting mechanism (upper clutch 50U) that switches between disconnection and connection of power in the first power transmission path; a second connecting / disconnecting mechanism (lower clutch 50D) that switches between disconnection and connection of power in the second power transmission path.

[0115] According to (2), the first and second interrupting mechanisms can appropriately switch between the two power transmission paths.

[0116] (3) A coupling device according to (2), The coupling device further includes a control unit (a motor control unit 108, an interrupting mechanism control unit 110) for controlling the first interrupting mechanism and the second interrupting mechanism, The control unit is a connection state in which either one of the first interruption mechanism and the second interruption mechanism is connected; a disconnected state (free state) in which the first and second interrupting mechanisms are disconnected, and a disconnected state (free state) in which the first and second interrupting mechanisms are disconnected.

[0117] According to (3), resistance can be generated when the connecting portion is extended and bent depending on the connected state, and no resistance can be generated when the connecting portion is extended and bent depending on the disconnected state.

[0118] (4) A coupling device according to (3), The joint device is provided to transition between a load-bearing state (standing leg) in which an external load is applied and a non-load-bearing state (free leg) in which no load is applied, The control unit is a weighted transition acquisition unit (weighted transition acquisition unit 113) that acquires a transition from the non-weighted state to the weighted state; an interruption mechanism control unit (motor control unit 108, interruption mechanism control unit 110) that controls the first interruption mechanism and the second interruption mechanism, The interrupting mechanism control unit is Controlling to the connected state when in the loaded state, and controlling to the disconnected state when in the non-loaded state; When the weighted transition acquisition unit acquires a transition from the non-weighted state to the weighted state, A coupling device that controls switching from the disconnected state to the connected state.

[0119] According to (4), by generating resistance in the joint when a load is applied, the joint can be prevented from suddenly bending under the load even when the power source is stopped. On the other hand, by not generating resistance in the joint when a load is not applied, the joint can be smoothly extended.

[0120] (5) A coupling device according to (4), The joint device is a prosthetic leg, If the knee angle (knee angle θ) is the angle obtained by subtracting the above angle from 180°, The weighted transition acquisition unit determines the transition based on the knee angle.

[0121] According to (5), by determining the transition from the swing leg to the stance leg based on the knee angle, contact between mechanical elements can be avoided and the generation of abnormal noise can be suppressed.

[0122] (6) A coupling device according to (5), The weighted transition acquisition unit determines the transition based on the weighting.

[0123] According to (6), the estimation accuracy of the transition from a non-weighted state to a weighted state can be improved.

[0124] (7) A coupling device according to (5) or (6), The first member is a lower-knee member and the second member is an upper-knee member, When the angle of the first member with respect to the vertical line passing through the connection portion is defined as the lower leg angle, The weighted transition acquisition unit determines the transition based on the angular velocity of the lower leg angle (lower leg angular velocity), the joint device.

[0125] According to (7), the estimation accuracy of the transition from a non-weighted state to a weighted state can be improved.

[0126] (8) A coupling device according to (3), The joint device is provided to transition between a load-bearing state (standing leg) in which an external load is applied and a non-load-bearing state (free leg) in which no load is applied, The control unit is a non-weighted transition acquisition unit (non-weighted transition acquisition unit 114) that acquires a transition from the weighted state to the non-weighted state; an interruption mechanism control unit (motor control unit 108, interruption mechanism control unit 110) that controls the first interruption mechanism and the second interruption mechanism, The interrupting mechanism control unit is Controlling to the connected state when in the loaded state, and controlling to the disconnected state when in the non-loaded state; When the non-weighted transition acquisition unit acquires a transition from the weighted state to the non-weighted state, A coupling device that controls switching from the connected state to the disconnected state.

[0127] According to (8), by appropriately switching the intermittent mechanism during the transition from the stance leg to the swing leg, a smooth transition can be achieved.

[0128] (9) A coupling device according to (8), The joint device is a prosthetic leg, The first member is a lower-knee member and the second member is an upper-knee member, When the angle of the first member with respect to the vertical line passing through the connection portion is defined as the lower leg angle, The non-weighted transition acquisition unit determines the transition based on the angular velocity of the lower leg angle (lower leg angular velocity) and the angular acceleration of the lower leg angle (lower leg angular acceleration), the joint device.

[0129] According to (9), it is possible to prevent the toes from getting caught on the ground.

[0130] (10) A coupling device according to (9), The non-weighted transition acquisition unit determines the transition based on the weighting.

[0131] According to (10), the estimation accuracy of the transition from a weighted state to a non-weighted state can be improved.

[0132] (11) A coupling device according to (9) or (10), When the angle of the second member with respect to the vertical line passing through the hip joint is defined as the thigh angle (thigh angle β), The non-weighted transition acquisition unit determines the transition based on the thigh angle.

[0133] According to (11), the estimation accuracy of the transition from a weighted state to a non-weighted state can be improved.

[0134] (12) a first member (knee-lower member 10); A second member (above-knee member 20), a joint portion (knee joint mechanism 30) that connects the first member and the second member in a manner that allows the angle between the first member and the second member to be changed; A joint device (electric prosthetic leg 1) including an extension device (extension device 40) that can change the angle between the first member and the second member by extending and contracting, The joint device is provided to transition between a load-bearing state (standing leg) in which an external load is applied and a non-load-bearing state (free leg) in which no load is applied, The telescopic device is A power source (motor M), a power transmission unit (transmission T) that transmits the power of the power source; an interrupting mechanism (interrupting mechanism 50) that switches between disconnection and connection of power in a power transmission path; An interruption mechanism control unit (motor control unit 108, interruption mechanism control unit 110) for controlling the interruption mechanism, The interrupting mechanism control unit is A coupling device that is controlled to a connected state when in the load-applied state, and is controlled to a disconnected state when in the non-load-applied state.

[0135] According to (12), the connecting part can be extended and bent via the power transmission part that transmits the power of the power source. In addition, by connecting the disconnecting mechanism when the load is applied, resistance can be generated when the connecting part is extended and bent, and the connecting part can be prevented from suddenly bending under the load even when the power source is stopped. On the other hand, by disconnecting the connecting mechanism, resistance is not generated when the connecting part is extended and bent, and the connecting part can be extended smoothly.

[0136] (13) A coupling device according to (12), The coupling device, wherein the interrupting mechanism control unit controls the coupling state to be switched from the disconnected state to the connected state when the coupling state transitions from the unloaded state to the loaded state or when the coupling state transition is predicted.

[0137] According to (13), the generation of abnormal noise can be suppressed by appropriately switching the on-off mechanism when transitioning from a non-loaded state to a loaded state.

[0138] (14) A coupling device according to (12), The coupling device, wherein the on / off mechanism control unit controls the coupling state to be switched from the connected state to the disconnected state when the coupling state transitions from the loaded state to the unloaded state or when the coupling state transition is predicted.

[0139] According to (14), by appropriately switching the on-off mechanism when transitioning from a loaded state to a non-loaded state, a smooth transition can be achieved. [Explanation of symbols]

[0140] 1. Electric prosthesis (joint device) 10 Lower knee member (first member) 20 Knee-up member (second member) 30 Knee joint mechanism (articulation) 40 Telescopic device 50 Intermittent Mechanism 50D Lower clutch (second intermittent mechanism) 50U Upper clutch (first intermittent mechanism) 108 Motor control unit (control unit) 110 Interrupting mechanism control unit (control unit) 113 Weighted transition acquisition unit M Motor (power source) T Transmission (power transmission section) T1 First transmission mechanism (first power transmission path) T2 Second transmission mechanism (second power transmission path)

Claims

1. A first member; A second member; a connecting portion that connects the first member and the second member in a manner that allows an angle between the first member and the second member to be changed; A joint device including an extension device capable of changing the angle between the first member and the second member by extending and contracting, The telescopic device is A power source; a power transmission unit that transmits the power of the power source, The power transmission unit includes: a first power transmission path that transmits the power at a first gear ratio; a second power transmission path that transmits the power at a second speed ratio different from the first speed ratio, The telescopic device is a first interrupting mechanism that switches between interruption and connection of power in the first power transmission path; a second interrupting mechanism that switches between interruption and connection of power in the second power transmission path, The coupling device further includes a control unit that controls the first interrupting mechanism and the second interrupting mechanism. The control unit is a connection state in which either one of the first interrupting mechanism and the second interrupting mechanism is connected; a disconnecting state in which the first interrupting mechanism and the second interrupting mechanism are disconnected, and a disconnecting state in which the first interrupting mechanism and the second interrupting mechanism are disconnected.

2. 2. The coupling device according to claim 1, The coupling device is provided to transition between a loaded state in which an external load is applied and a non-loaded state in which no load is applied, The control unit is a weighted transition acquisition unit that acquires a transition from the non-weighted state to the weighted state; an interrupting mechanism control unit that controls the first interrupting mechanism and the second interrupting mechanism, The interrupting mechanism control unit is Controlling to the connected state when in the loaded state, and controlling to the disconnected state when in the non-loaded state; When the weighted transition acquisition unit acquires a transition from the non-weighted state to the weighted state, A coupling device that controls switching from the disconnected state to the connected state.

3. 3. The coupling device according to claim 2, The joint device is a prosthetic leg, If the knee angle is the angle obtained by subtracting the above angle from 180°, The weighted transition acquisition unit determines the transition based on the knee angle.

4. 4. The coupling device according to claim 3, The weighted transition acquisition unit determines the transition based on the weighting.

5. A coupling device according to claim 3 or 4, The first member is a lower-knee member and the second member is an upper-knee member, When the angle of the first member with respect to a vertical line passing through the connection portion is defined as a lower leg angle, The weighted transition acquisition unit determines the transition based on the angular velocity of the lower leg angle.

6. 2. The coupling device according to claim 1, The coupling device is provided to transition between a loaded state in which an external load is applied and a non-loaded state in which no load is applied, The control unit is a non-weighted transition acquisition unit that acquires a transition from the weighted state to the non-weighted state; an interrupting mechanism control unit that controls the first interrupting mechanism and the second interrupting mechanism, The interrupting mechanism control unit is Controlling to the connected state when in the loaded state, and controlling to the disconnected state when in the non-loaded state; When the non-weighted transition acquisition unit acquires a transition from the weighted state to the non-weighted state, A coupling device that controls switching from the connected state to the disconnected state.

7. 7. A coupling device according to claim 6, The joint device is a prosthetic leg, The first member is a lower-knee member and the second member is an upper-knee member, When the angle of the first member with respect to a vertical line passing through the connection portion is defined as a lower leg angle, The non-weighted transition acquisition unit determines the transition based on the angular velocity of the lower leg angle and the angular acceleration of the lower leg angle.

8. 8. A coupling device according to claim 7, The non-weighted transition acquisition unit determines the transition based on the weighting.

9. A coupling device according to claim 7 or 8, When the angle of the second member with respect to a vertical line passing through the hip joint is defined as a thigh angle, The non-weighted transition acquisition unit determines the transition based on the thigh angle.

10. A first member; A second member; a connecting portion that connects the first member and the second member in a manner that allows an angle between the first member and the second member to be changed; A joint device including an extension device capable of changing the angle between the first member and the second member by extending and contracting, The coupling device is provided to transition between a loaded state in which an external load is applied and a non-loaded state in which no load is applied, The telescopic device is A power source; a power transmission unit that transmits the power of the power source; an interrupting mechanism for switching between interruption and connection of power in a power transmission path; An interruption mechanism control unit for controlling the interruption mechanism, The interrupting mechanism control unit is A coupling device that is controlled to a connected state when in the load-applied state, and is controlled to a disconnected state when in the non-load-applied state.

11. 11. The coupling device of claim 10, The coupling device, wherein the interrupting mechanism control unit controls the coupling state to be switched from the disconnected state to the connected state when the coupling state transitions from the unloaded state to the loaded state or when the coupling state transition is predicted.

12. 11. The coupling device of claim 10, The coupling device, wherein the on / off mechanism control unit controls the coupling state to be switched from the connected state to the disconnected state when the coupling state transitions from the loaded state to the unloaded state or when the coupling state transition is predicted.

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