Motion assistance device

Abstract

An exercise assistance device includes a first link; a second link coupled to the first link via a rotating shaft for rotation; a pipe fixed to the first link; an electromagnet arranged to cover at least a part of the pipe; a first movable part connected to a first end of the pipe; a second movable part connected to a second end of the pipe; a magnetic fluid filled in a sealed space defined by the pipe, the first movable part, and the second movable part; a transmission part configured to convert a relative rotation between the first link and the second link into a relative position change between the first movable part and the second movable part; and a control unit configured to control the electromagnet.

Description

Technical Field

[0001] The present disclosure relates to a motion assistance device. Background Art

[0002] When a walking training is performed, for example, by a hemiplegic patient or the like, a motion assistance device is worn on the affected leg to prevent knee flexion of the affected leg. As described in Japanese Unexamined Patent Application Publication No. 2018-114175 (JP2018-114175A), such a motion assistance device includes a thigh link attached to the thigh of the user's affected leg, a calf link attached to the calf of the affected leg via a knee joint portion and coupled to the thigh link, a motor unit that drives the knee joint portion, and the like. The motion assistance device is configured to generate a resistance by using the driving force of the motor unit to prevent knee flexion of the user's affected leg. Summary of the Invention

[0003] The applicant has found the following challenges. General motion assistance devices are configured to generate a resistance by using a motor unit to prevent knee flexion of the user's affected leg. For this reason, the mechanism for generating a resistance to resist the rotational movement of the user's joint becomes complicated, so it is difficult to achieve both high resistance and size reduction at the same time.

[0004] The present disclosure achieves both simplification and size reduction of a motion assistance device.

[0005] One aspect of the present disclosure relates to a motion assistance device. The motion assistance device is configured to be worn on a joint of a user. The motion assistance device includes a first link; a second link that is coupled to the first link via a rotation axis so as to be rotatable; a pipe that is fixed to the first link; an electromagnet that is arranged to cover at least a part of the pipe; a first movable part that is connected to a first end of the pipe so as to communicate with the pipe and is configured to contain a magnetic fluid; a second movable part that is connected to a second end of the pipe so as to communicate with the pipe and is configured to contain a magnetic fluid; a magnetic fluid that is filled in a sealed space defined by the pipe, the first movable part, and the second movable part; a transmission part that is configured to convert a relative rotation between the first link and the second link into a relative position change between the first movable part and the second movable part; and a control unit that is configured to control the electromagnet.

[0006] In the motion assistance device, at least a part of the pipe covered with the electromagnet may be made of a magnetic permeable material.

[0007] In the motion assistance device, the pipe may include a bent portion; and the electromagnet may be arranged to cover at least a part of the bent portion.

[0008] The motion assistance device may further include a bypass passage that is connected in parallel with the pipe; and a check valve that is provided in the bypass passage.

[0009] In the motion assistance device, the transmission unit may include: a first storage unit in a closed-end cylindrical shape, which is connected to the first link so as to slide on the first link; a second storage unit in a closed-end cylindrical shape, which is connected to the first link so as to slide on the first link; a pinion gear fixed to a rotating shaft; and a first rack engaged with the pinion gear and fixed to the first storage unit; in a state where the first movable part is accommodated in the first storage unit, a distal end of the first movable part may be connected to a bottom of the first storage unit; and in a state where the second movable part is accommodated in the second storage unit, a distal end of the second movable part may be connected to a bottom of the second storage unit.

[0010] The motion assistance device may further include a second rack engaged with the pinion gear and fixed to the second storage unit.

[0011] In the motion assistance device, the transmission unit may include: a first storage unit in a closed-end cylindrical shape, which is connected to the first link so as to slide on the first link; a second storage unit in a closed-end cylindrical shape, which is connected to the first link so as to slide on the first link; an arm fixed to the second link; a first rod connecting a first end of the arm and the first storage unit; and a second rod connecting a second end of the arm and the second storage unit; in a state where the first movable part is accommodated in the first storage unit, a distal end of the first movable part may be connected to a bottom of the first storage unit; and in a state where the second movable part is accommodated in the second storage unit, a distal end of the second movable part may be connected to a bottom of the second storage unit.

[0012] The motion assistance device may further include: a first cover portion assembled to an opening of the first storage unit so as to be displaceable relative to the first storage unit and disposed between a first end of a pipeline and the first movable part; and a second cover portion assembled to an opening of the second storage unit so as to be displaceable relative to the second storage unit and disposed between a second end of the pipeline and the second movable part; the first cover portion may include a through portion configured to communicate the pipeline with the first movable part; and the second cover portion may include a through portion configured to communicate the pipeline with the second movable part.

[0013] In the motion assistance device, the first movable part may be configured to extend and contract; and the second movable part may be configured to extend and contract.

[0014] In the motion assistance device, the first movable part may include a bellows; and the second movable part may include a bellows.

[0015] In the motion assistance device, the first movable part may be in a closed-end cylindrical shape; and the second movable part may be in a closed-end cylindrical shape.

[0016] In the motion assistance device, the first storage unit may be connected to the first link via a slider so as to slide on the first link; and the second storage unit may be connected to the first link via a slider so as to slide on the first link.

[0017] In the motion assistance device, the control unit may be configured to control the voltage applied to the electromagnet.

[0018] In the motion assistance device, the control unit may be configured to control the start and stop of applying voltage to the electromagnet.

[0019] According to an aspect of the present disclosure, simplification and size reduction of the motion assistance device can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the drawings, in which like reference numerals denote like elements, and wherein:

[0021] Figure 1 is a view showing a motion assistance device according to a first embodiment;

[0022] Figure 2 is a cross-sectional view taken along line II-II in Figure 1 ;

[0023] Figure 3 is a block diagram showing a control system of the motion assistance device according to the first embodiment;

[0024] Figure 4 is a view showing a state in which the motion assistance device according to the first embodiment is worn on a user's diseased leg.

[0025] Figure 5 is a view showing a motion assistance device according to a second embodiment;

[0026] Figure 6 is a view showing a portion around the electromagnet in the motion assistance device according to a third embodiment;

[0027] Figure 7 is a view showing a motion assistance device according to a fourth embodiment; and

[0028] Figure 8 is a view showing a motion assistance device according to a fifth embodiment. DETAILED DESCRIPTION

[0029] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. For clarity, the following description and drawings have been simplified as needed.

[0030] First Embodiment

[0031] First, the configuration of the motion assist device according to the present embodiment will be described. Figure 1 is a view showing the motion assist device according to the present embodiment. Figure 2 is along Figure 1 a cross-sectional view taken along line II-II in Figure 3 is a block diagram showing the control system of the motion assist device according to the present embodiment.

[0032] In the following description, for clarity, the motion assist device 1 will be described using an orthogonal coordinate system (XYZ coordinate system) in a state where the first link 2 and the second link 3 are arranged in a straight line as Figure 1 shown.

[0033] For example, as Figures 1 to 3 shown, the motion assist device 1 includes a first link 2, a second link 3, a pipe 4, an electromagnet 5, a first movable part 6, a second movable part 7, a magnetic fluid 8, a transmission part 9, and a control unit 10. The first link 2 has, for example, a plate shape substantially parallel to the YZ plane. The first link 2 includes a first part 2a and a second part 2b.

[0034] The first part 2a has, for example, a substantially rectangular shape, and when viewed in the X-axis direction, its long side is in the Z-axis direction. The second part 2b is arranged on the negative Z-axis side with respect to the first part 2a. The width of the second part 2b in the Y-axis direction is greater than the width of the first part 2a in the Y-axis direction. The second part 2b has, for example, a substantially rectangular shape when viewed in the X-axis direction, and both corners on the positive Z-axis side of the second part 2b are cut off.

[0035] As Figure 1 and Figure 2 shown, the second link 3 is arranged on the negative X-axis side with respect to the first link 2. The second link 3 has, for example, a plate shape substantially parallel to the YZ plane and a substantially rectangular shape with a long side in the Z-axis direction when viewed in the X-axis direction. The positive Z-axis end of the second link 3 is rotatably coupled to the negative Z-axis end of the first link 2 via a rotary shaft 11.

[0036] As Figure 2 shown, the rotary shaft 11 projects from the positive Z-axis end of the second link 3 toward the positive X-axis side. The rotary shaft 11 is inserted into a through hole 2c formed in the negative Z-axis end of the first link 2.

[0037] Accordingly, the first link 2 and the second link 3 are configured to be relatively rotatable. An encoder 12 is provided on the first link 2 (see Figure 3), so as to be able to detect the rotation angle of the rotation axis 11 relative to the first link 2. The rotation angle of the second link 3 relative to the first link 2 can be detected by an encoder.

[0038] For example, as Figure 1 shown, when observed in the X-axis direction, the pipeline 4 has a substantially inverted U shape. For example, as Figure 2 shown, both ends of the pipeline 4 are fixed to the positive X-axis surface of the second part 2b of the first link 2 via the fixing fixture 13.

[0039] Here, in the pipeline 4, as will be described later, the portion covered by the electromagnet 5 can be made of a magnetic permeable material, such as metal, while the other portion can be made of any material and can be made of metal, resin, etc.

[0040] As Figure 1 and Figure 2 shown, the electromagnet 5 is fixed to the positive X-axis surface of the second part 2b of the first link 2 so as to cover at least a part of the pipeline 4. The electromagnet 5 includes an iron core 51 and a coil 52.

[0041] For example, as Figure 2 shown, when observed in the Y-axis direction, the iron core 51 has a substantially C shape. In a state where the pipeline 4 is clamped by the positive X-axis opening of the iron core 51, the iron core 51 extends in the Y-axis direction. The coil 52 is arranged to surround the iron core 51.

[0042] As long as the electromagnet 5 can apply a magnetic field to the magnetic fluid 8 flowing through the conduit 4 (which will be described later), the structure and arrangement of the electromagnet 5 are not limited. In Figure 1 etc., the coil 52 is shown in a simplified view.

[0043] As Figure 1 shown, the first movable part 6 is connected to the positive Y-axis end of the pipeline 4 so as to communicate with the pipeline 4. The first movable part 6 is made of, for example, a resin bellows. The first movable part 6 has a storage part, and the storage part contains the magnetic fluid 8 inside.

[0044] In other words, the first movable part 6 is in the shape of a closed-end cylinder and can expand and contract. The first movable part 6 is arranged to be able to expand and contract in the Z-axis direction. The positive Z-axis opening end of the first movable part 6 is connected to the positive Y-axis end of the pipeline 4.

[0045] As Figure 1 shown, the second movable part 7 is connected to the negative Y-axis end of the pipeline 4 so as to communicate with the pipeline 4. The second movable part 7 is made of, for example, a resin bellows. The second movable part 7 has a storage part, and the storage part contains the magnetic fluid 8 inside.

[0046] In other words, the second movable part 7 is also a closed-end cylindrical shape and can be extended and contracted. The second movable part 7 is arranged to be able to expand and contract in the Z-axis direction. The positive Z-axis opening end of the second movable part 7 is connected to the negative Y-axis end of the pipeline 4.

[0047] Therefore, a substantially sealed space is defined by the pipeline 4, the first movable part 6, and the second movable part 7. Each of the first movable part 6 and the second movable part 7 only needs to be configured such that the volume inside the first movable part 6 and the volume inside the second movable part 7 change relatively due to deformation or displacement in the Z-axis direction, and can be made of, for example, a bag body or the like.

[0048] The magnetic fluid 8 is a liquid obtained by dispersing magnetic particles in a solvent, similar to the case of a general magnetorheological (MR) fluid. The magnetic fluid 8 is filled in the substantially sealed space defined by the pipeline 4, the first movable part 6, and the second movable part 7.

[0049] The transmission part 9 converts the relative rotation between the first link 2 and the second link 3 into a relative position change in the Z-axis direction between the first movable part 6 and the second movable part 7. For example, as Figure 1 shown, the transmission part 9 includes a first storage part 91, a second storage part 92, a pinion 93, a first rack 94, and a second rack 95. In Figure 1 it, the pinion 93, the first rack 94, and the second rack 95 are shown in a simplified view.

[0050] The first storage part 91 is arranged on the positive Y-axis side with respect to the rotation axis 11. The first storage part 91 is of a closed-end cylindrical shape and has an opening at the positive Z-axis end of the first storage part 91. In other words, the first storage part 91 includes a cylindrical part 91a extending through in the Z-axis direction, and a bottom part 91b closing the negative Z-axis end of the cylindrical part 91a.

[0051] As Figure 2 shown, the first storage part 91 is connected to the positive X-axis surface of the second part 2b of the first link 2 via a slider 96 so as to be slidable in the Z-axis direction. The first movable part 6 is accommodated in the first storage part 91, and the negative Z-axis end of the first movable part 6 is connected to the bottom part 91b of the first storage part 91.

[0052] At this time, although the detailed functions will be described later, the first cover part 14 arranged between the positive Y-axis end of the pipeline 4 and the first movable part 6 can be inserted into the first storage part 91. More specifically, the first cover part 14 has a columnar shape as its basic form, the circumferential shape of which is substantially the same as the inner shape of the cylindrical part 91a of the first storage part 91, and the first cover part 14 includes a through hole extending through the first cover part 14 in the Z-axis direction.

[0053] With the positive Y-axis end of the pipeline 4 connected to the positive Z-axis end of the first cover part 14 and the positive Z-axis opening end of the first movable part 6 connected to the negative Z-axis end of the first cover part 14, the first cover part 14 is inserted into the cylindrical part 91a of the first storage part 91. At this time, the first cover part 14 is fixed to the second part 2b of the first link 2 via the fixing jig 13.

[0054] Therefore, while the first cover part 14 closes the opening of the first storage part 91 to form a substantially sealed space, the first cover part 14 and the first storage part 91 are assembled together such that the first storage part 91 can slide relative to the first cover part 14. The pipeline 4 and the first movable part 6 communicate with each other via the first cover part 14.

[0055] The second storage part 92 is arranged on the negative Y-axis side with respect to the rotation axis 11. The second storage part 92 has a closed-end cylindrical shape and has an opening at the positive Z-axis end of the second storage part 92. In other words, the second storage part 92 includes a cylindrical part 92a extending through in the Z-axis direction and a bottom part 92b closing the negative Z-axis end of the cylindrical part 92a.

[0056] The second storage part 92 is connected to the positive X-axis surface of the second part 2b of the first link 2 via a slider (not shown) so as to be slidable in the Z-axis direction. As Figure 1 shown, the second movable part 7 is accommodated in the second storage part 92, and the negative Z-axis end of the second movable part 7 is connected to the bottom part 92b of the second storage part 92.

[0057] At this time, although the detailed functions will be described later, the second cover part 15 arranged between the negative Y-axis end of the pipeline 4 and the second movable part 7 can be inserted into the second storage part 92. More specifically, the second cover part 15 has a columnar shape as a basic form, the circumferential shape of which is substantially the same as the internal shape of the cylindrical part 92a of the second storage part 92, and the second cover part 15 includes a through hole extending through in the Z-axis direction.

[0058] With the negative Y-axis end of the pipeline 4 connected to the positive Z-axis end of the second cover part 15 and the positive Z-axis opening end of the second movable part 7 connected to the negative Z-axis end of the second cover part 15, the second cover part 15 is inserted into the cylindrical part 92a of the second storage part 92. At this time, the second cover part 15 is fixed to the second part 2b of the first link 2 via the fixing jig 13.

[0059] Therefore, while the second cover part 15 closes the opening of the second storage part 92 to form a substantially sealed space, the second cover part 15 and the second storage part 92 are assembled together such that the second storage part 92 can slide relative to the second cover part 15. The pipeline 4 and the second movable part 7 communicate with each other via the second cover part 15.

[0060] As Figure 1 and Figure 2 shown, the pinion gear 93 is fixed to the rotating shaft 11. The first rack 94 is fixed to the cylindrical portion 91a of the first storage portion 91 and extends in the Z-axis direction. The first rack 94 meshes with the pinion gear 93. The second rack 95 is fixed to the cylindrical portion 92a of the second storage portion 92 and extends in the Z-axis direction. The second rack 95 meshes with the pinion gear 93.

[0061] The transmission unit 9 only needs to be arranged such that the components can move without interference even when the user extends or bends the affected leg.

[0062] The control unit 10 controls the electromagnet 5. More specifically, for example, when the value obtained from the rotation angle of the second link 3 relative to the first link 2 based on the detection signal of the encoder 12 exceeds a preset threshold (i.e., the value becomes greater than the threshold or the value becomes less than the threshold), the control unit 10 applies the voltage from the power supply 16 to the coil 52 of the electromagnet 5. On the other hand, for example, when the affected leg of the user is in the swing leg state based on the detection result of the sensor for detecting the landing of the affected leg while the motion assist device 1 is worn on the affected leg of the user (as will be described later), the control unit 10 may stop applying the voltage to the coil 52 of the electromagnet 5.

[0063] Next, the state in which the motion assist device 1 according to the present embodiment is worn on the user will be described. Figure 4 is a view showing the state in which the motion assist device according to the present embodiment is worn on the affected leg of the user. As Figure 4 shown, when, for example, the user (such as a hemiplegic patient) performs walking training, the motion assist device 1 is put on the affected leg L of the user, the first link 2 is fixed to the thigh of the affected leg L via the first fixing device 17 (such as a belt), and the second link 3 is fixed to the calf of the affected leg L via the second fixing device 18 (such as a belt).

[0064] Therefore, the motion assist device 1 can be worn on the affected leg L of the user. At this time, in the state where the first link 2 and the second link 3 are arranged in a straight line, the positive Z-axis side of the motion assist device 1 is the root side of the affected leg L, and the negative Z-axis side of the motion assist device 1 is the heel side of the affected leg L.

[0065] Next, the operation of the motion assist device 1 according to the present embodiment will be described. When the control unit 10 does not apply voltage to the coil 52 of the electromagnet 5 via the power supply 16, the flow of the magnetic fluid 8 is not restricted in the substantially sealed space defined by the pipeline 4, the first movable portion 6, and the second movable portion 7, and the user can bend the affected leg L without resistance, as Figure 1 and Figure 4 shown.

[0066] At this time, when the second link 3 rotates relative to the first link 2 in the direction of arrow A, the pinion gear 93 rotates, and thus, the second storage portion 92 moves toward the root of the affected leg L via the second rack 95, and the first storage portion 91 moves toward the heel of the affected leg L via the first rack 94. Accordingly, the second movable portion 7 contracts, the first movable portion 6 extends, and the magnetic fluid 8 moves from the second movable portion 7 to the first movable portion 6 via the pipe line 4.

[0067] Conversely, when the second link 3 rotates relative to the first link 2 in the direction of arrow B, the pinion gear 93 rotates, and thus, the second storage portion 92 moves toward the heel of the affected leg L via the second rack 95, and the first storage portion 91 moves toward the root of the affected leg L via the first rack 94. Accordingly, the first movable portion 6 contracts, the second movable portion 7 extends, and the magnetic fluid 8 moves from the first movable portion 6 to the second movable portion 7 via the pipe line 4.

[0068] On the other hand, when the control unit 10 applies a voltage to the coil 52 of the electromagnet 5 via the power supply 16, the viscosity of the magnetic fluid 8 in the portion around the electromagnet 5 in the pipe line 4 increases, and as a result, the flow of the magnetic fluid 8 in the substantially sealed space defined by the pipe line 4, the first movable portion 6, and the second movable portion 7 is restricted. At this time, the motion assist device 1 generates a resistance against the rotation of the second link 3 relative to the first link 2, and as a result, the bending of the affected leg L is restricted.

[0069] In this way, the motion assist device 1 according to the present embodiment is configured to generate a resistance against the rotation of the second link 3 relative to the first link 2 by applying a magnetic field to the magnetic fluid 8. Therefore, the motion assist device 1 according to the present embodiment has a simple configuration as compared with a general motion assist device, and can achieve simplification and size reduction.

[0070] Further, in the motion assist device 1 according to the present embodiment, the first movable portion 6 is accommodated in a substantially sealed space defined by the first cover portion 14 and the first storage portion 91, and the second movable portion 7 is accommodated in a substantially sealed space defined by the second cover portion 15 and the second storage portion 92. Therefore, even when the first movable portion 6 or the second movable portion 7 is damaged, it is possible to prevent the magnetic fluid 8 from leaking to the outside of the motion assist device 1.

[0071] In the motion assist device 1 according to the present embodiment, when at least a part of the portion of the pipe line 4 covered with the electromagnet 5 is made of a magnetic permeable material, the magnetic density of the magnetic fluid 8 increases when a voltage is applied to the electromagnet 5 as compared with when the pipe line 4 is not made of a magnetic permeable material. Therefore, the size of the electromagnet 5 is reduced as compared with the case where the pipe line 4 is not made of a magnetic permeable material.

[0072] Second Embodiment

[0073] Figure 5 is a view showing a motion assist device according to the present embodiment. The configuration of the motion assist device 101 according to the present embodiment is basically similar to that of the motion assist device 1 according to the first embodiment, except that the rotation of the pinion gear 93 is configured to be transmitted only to the first storage unit 91, as Figure 5 shown.

[0074] Therefore, as Figure 5 shown, it is not necessary to configure the first storage unit 91 and the second storage unit 92 such that the rotation shaft 11 penetrates in the Y-axis direction, and thus the width of the motion assist device 1 in the Y-axis direction is reduced.

[0075] In the present embodiment, as Figure 5 shown, the rotation of the pinion gear 93 is transmitted only to the first storage unit 91. Alternatively, the rotation of the pinion gear 93 may be transmitted only to the second storage unit 92. In the present embodiment, the second movable part 7, the second storage unit 92, etc. are provided on the first link 2. Alternatively, the second movable part 7, the second storage unit 92, etc. may be provided on the second link 3.

[0076] Third Embodiment

[0077] Figure 6 is a view showing a portion around an electromagnet in a motion assist device according to the present embodiment. The configuration of the motion assist device according to the present embodiment is basically similar to that of the motion assist device 1 according to the first embodiment, except that the pipe 4 has a bent portion 4a and the bent portion 4a is at least partially covered with the electromagnet 5, as Figure 6 shown.

[0078] In this way, when the pipe 4 has the bent portion 4a, as Figure 6 shown, it is possible to apply a magnetic flux substantially parallel to the flow of the magnetic fluid 8, and thus, compared with when the pipe 4 has no bent portion 4a, it is possible to generate a large resistance against the rotation of the second link 3 relative to the first link 2. Figure 6 The wide arrow in

[0079] represents the magnetic flux generated by the electromagnet 5.

[0080] Figure 7 is a view showing a motion assist device according to the present embodiment. Figure 7 The motion assist device is simplified by omitting a part of the first link 2, the second link 3, the transmission part 9, etc. The configuration of the motion assist device 401 according to the present embodiment is basically similar to that of the motion assist device 1 according to the first embodiment, except that a bypass channel 402 is connected in parallel with the pipe 4, as Figure 7as shown

[0081] A one-way valve 403 is provided in the bypass passage 402. The one-way valve 403 is provided in the bypass passage 402 so as to allow, for example, the magnetic fluid 8 to flow from the first movable part 6 to the second movable part 7 and cut off the flow of the magnetic fluid 8 from the second movable part 7 to the first movable part 6.

[0082] Therefore, even when a voltage is applied to the electromagnet 5 and the flow of the magnetic fluid 8 in the pipeline 4 is restricted, the magnetic fluid 8 can flow from the first movable part 6 to the second movable part 7 via the bypass passage 402. Therefore, the extension of the diseased leg L can be allowed while preventing the knee flexion of the diseased leg L.

[0083] However, depending on the details of the motion assistance, the one-way valve 403 according to the present embodiment may be provided in the bypass passage 402 so as to cut off the flow of the magnetic fluid 8 from the first movable part 6 to the second movable part 7 and allow the magnetic fluid 8 to flow from the second movable part 7 to the first movable part 6.

[0084] Fifth Embodiment

[0085] Figure 8 is a view showing the motion assistance device according to the present embodiment. The configuration of the motion assistance device 501 according to the present embodiment is basically similar to that of the motion assistance device 1 according to the first embodiment, except that the configuration of the transmission part 502 is different, as Figure 8 as shown

[0086] In the following description, for the sake of clarity, the configuration of the motion assistance device 501 in a state where the first link 2 and the second link 3 are arranged in a straight line as Figure 8 shown will be described by using an orthogonal coordinate system (XYZ coordinate system).

[0087] In the motion assistance device 501 according to the present embodiment, the second part 2b of the first link 2 is longer in the Z-axis direction than the second part 2b of the first link 2 according to the first embodiment, and the second link 3 is arranged on the positive X-axis side with respect to the first link 2.

[0088] The rotation shaft 11 protrudes from the positive Z-axis end of the second link 3 toward the negative X-axis side and is inserted into the through hole formed at the negative Z-axis end of the first link 2. At this time, the rotation shaft 11 is arranged on the negative Z-axis side with respect to the first storage part 91 and the second storage part 92.

[0089] The transmission part 502 includes an arm 503, a first rod 504, and a second rod 505. The arm 503 has a plate-like shape substantially parallel to the YZ plane and has a substantially rectangular shape with a long side in the Y-axis direction when viewed in the X-axis direction.

[0090] The arm 503 is fixed to the positive Z-axis end of the second link 3. At this time, the amount of protrusion of the arm 503 from the rotation axis 11 toward the positive Y-axis is substantially equal to the amount of protrusion of the arm 503 from the rotation axis 11 toward the negative Y-axis.

[0091] The first rod 504 has, for example, a rod shape and connects the positive Y-axis end of the arm 503 and the bottom 91b of the first storage portion 91. In other words, the positive Z-axis end of the first rod 504 is rotatably connected to the bottom 91b of the first storage portion 91, and the negative Z-axis end of the first rod 504 is rotatably connected to the positive Y-axis end of the arm 503.

[0092] The second rod 505 has, for example, a rod shape with a length substantially equal to that of the first rod 504 and connects the negative Y-axis end of the arm 503 and the bottom 92b of the second storage portion 92. In other words, the positive Z-axis end of the second rod 505 is rotatably connected to the bottom 92b of the second storage portion 92, and the negative Z-axis end of the second rod 505 is rotatably connected to the negative Y-axis end of the arm 503.

[0093] With the above-described link structure transmission portion 502, the rotation of the second link 3 relative to the first link 2 can be converted into a change in the relative position in the Z-axis direction between the first movable portion 6 and the second movable portion 7 via the first storage portion 91 and the second storage portion 92.

[0094] In the present embodiment, the first storage portion 91 and the second storage portion 92 are arranged adjacent to each other in the Y-axis direction. Even when the first storage portion 91 and the second storage portion 92 are arranged adjacent to each other in the X-axis direction, a similar operation can be achieved. At this time, the rotation axis 11 can be used as the crankshaft of the engine, and the first rod 504 and the second rod 505 can be used as the connecting rods of the engine.

[0095] The present disclosure is not limited to the above-described embodiments and can be modified as needed without departing from the scope of the present disclosure.

[0096] For example, the first movable portion can be constituted by the first storage portion 91, and the second movable portion can be constituted by the second storage portion 92. At this time, a substantially sealed space can be defined by the pipeline 4, the first storage portion 91, the first cover portion 14, the second storage portion 92, and the second cover portion 15, and the magnetic fluid 8 can be filled in the substantially sealed space.

[0097] For example, the transmission portion can be configured to be able to convert the relative rotation between the first link 2 and the second link 3 into a change in the relative position between the first movable portion and the second movable portion in a state where the first link 2 and the second link 3 are coupled by the rotation axis 11.

[0098] For example, in the above-described embodiment, the substantially sealed space is defined by the first lid portion 14 and the first storage portion 91, and the substantially sealed space is defined by the second lid portion 15 and the second storage portion 92; however, the substantially sealed space does not always need to be defined. For example, the first lid portion 14 and the second lid portion 15 may be omitted.

[0099] For example, in the first embodiment and the like, the width of the pipeline 4 is substantially equal throughout the entire length. Alternatively, the inner diameter of a part of the pipeline 4 may be reduced. At this time, the part where the inner diameter of the pipeline 4 is reduced is exactly the part that needs to be covered by the electromagnet 5. Therefore, a high magnetic flux density of the magnetic fluid 8 can be maintained.

[0100] For example, in the above-described embodiment, an example of wearing the motion assistance device on the affected leg L of the user is described. Alternatively, the motion assistance device may be worn on the user's arm.

[0101] For example, not only when the rotation angle of the second link 3 with respect to the first link 2 exceeds a preset threshold value, a voltage is applied to the coil 52 of the electromagnet 5, but also based on, for example, the detection result of a sensor that detects the tilt angle of the first link 2 with respect to the ground or the landing of the affected leg L, a voltage is applied to the coil 52 of the electromagnet 5. In other words, it is only necessary to apply a voltage to the coil 52 of the electromagnet 5 such that a predetermined movement of the user's joint is restricted in a state where the motion assistance device is worn on the user.

[0102] For example, when it is detected based on the detection result of a sensor that detects the landing of the user's affected leg that the affected leg is in a swing leg state, not only is the application of voltage to the coil 52 of the electromagnet 5 stopped, but also the application of voltage to the coil 52 of the electromagnet 5 can be stopped at a time desired by the user. For example, when a preset time has elapsed since the voltage was applied to the coil 52 of the electromagnet 5, the application of voltage to the coil 52 of the electromagnet 5 can be stopped.

Claims

1. A motion assistance device configured to be worn on a joint of a user, the motion assistance device characterized by comprising: A first link; A second link rotatably coupled to the first link via a rotating shaft; A pipe fixed to the first link; An electromagnet arranged to cover at least a portion of the pipe; A first movable part connected to a first end of the pipe to communicate with the pipe and configured to contain a magnetic fluid; A second movable part connected to a second end of the pipe to communicate with the pipe and configured to contain the magnetic fluid; The magnetic fluid filled in a sealed space defined by the pipe, the first movable part, and the second movable part; A transmission part configured to convert a relative rotation between the first link and the second link into a relative position change between the first movable part and the second movable part; And A control unit configured to control the electromagnet, wherein The transmission part includes A first storage part in a closed-end cylindrical shape connected to the first link to slide on the first link, A second storage part in a closed-end cylindrical shape connected to the first link to slide on the first link, A pinion fixed to the rotating shaft, and A first rack meshing with the pinion and fixed to the first storage part; In a state where the first movable part is received in the first storage part, a distal end of the first movable part is connected to a bottom of the first storage part; And In a state where the second movable part is received in the second storage part, a distal end of the second movable part is connected to a bottom of the second storage part.

2. The motion assistance device according to claim 1, wherein At least a portion of the pipe covered by the electromagnet is made of a magnetic permeable material.

3. The motion assistance device according to claim 1, characterized in that: The pipe includes a bent portion; and The electromagnet is arranged to cover at least a portion of the bent portion.

4. The motion assistance device according to claim 1, wherein Further comprising: A bypass channel connected in parallel with the pipe; And A one-way valve provided in the bypass channel.

5. The motion assistance device according to claim 1, characterized in that Further comprising a second rack meshing with the pinion and fixed to the second storage part.

6. The motion assistance device according to claim 1, wherein Further comprising: A first cover part assembled to an opening of the first storage part to be displaceable relative to the first storage part and arranged between the first end of the pipe and the first movable part; And A second cover part assembled to an opening of the second storage part to be displaceable relative to the second storage part and arranged between the second end of the pipe and the second movable part, characterized in that: The first cover part includes a through hole configured to communicate the pipe with the first movable part; and The second cover part includes a through hole configured to communicate the pipe with the second movable part.

7. The motion assistance device according to claim 1, characterized in that: The first movable part is configured to extend and contract; and The second movable part is configured to extend and contract.

8. The motion assistance device according to claim 7, characterized in that: The first movable part includes a bellows; and The second movable part includes a bellows.

9. The motion assistance device according to claim 1, wherein: The first movable part is a closed-end cylindrical shape; and The second movable part is a closed-end cylindrical shape.

10. The motion assistance device according to claim 1, wherein: The first storage part is connected to the first link via a slider so as to slide on the first link; and The second storage part is connected to the first link via a slider so as to slide on the first link.

11. The motion assistance device according to any one of claims 1 to 10, characterized in that, The control unit is configured to control the voltage applied to the electromagnet.

12. The motion assistance device according to claim 11, characterized in that, The control unit is configured to control the start and stop of applying the voltage to the electromagnet.

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