Assist force generation device and motion assist apparatus

Abstract

To provide an assist force generation device and a motion assist apparatus in which an assist force can be changed using only a mechanical configuration.SOLUTION: An assist force generation device 20 includes an assist force changing mechanism 40 that is connected to a first end portion 26A and is capable of changing a position of the first end portion 26A with respect to a second end portion 26B. The assist force changing mechanism 40 includes: a rotor 42 which is provided so as to be rotatable about a rotation shaft 41A with respect to base portions 22A and 22B, and has an eccentric shaft 42B provided at a position apart from the rotation shaft 41A; and a link 43 which includes a first link end portion 43B and a second link end portion 43C and in which the first link end portion 43B is rotatably connected to the eccentric shaft 42B of the rotor 42, and the first end portion 26A is supported at the second link end portion 43C. By movement of the link 43 accompanying rotation of the rotor 42, the position of the first end portion 26A with respect to the second end portion 26B can be changed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an assistive force generation device and a motion assist device. [Background technology]

[0002] In the assist device of Patent Document 1, the reciprocating swinging motion of the output link accompanying the user's walking is input to the inner end of the spiral spring via the reducer and the input / output side power transmission means, and elastic energy is accumulated in the spiral spring. The rotation of the spiral spring in the return direction is output to the output link via the reducer and the input / output side power transmission means, causing the output link to swing, thereby assisting the user's walking.

[0003] By driving the drive motor to rotate the motor output shaft, the stiffness adjustment member is rotationally driven via the stiffness adjustment power transmission means, and the outer end of the spiral spring is rotated, thereby changing the assist force of the spiral spring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6638411 Summary of the Invention [Problem to be solved by the invention]

[0005] The assist device of Patent Document 1 uses a drive motor to change the assist force of the spiral spring, so in addition to mechanical components such as the spiral spring, it also requires electrical components such as a control means for controlling the drive motor and a battery for supplying power to the drive motor. As a result, the assist device has a complex configuration and the wearer has to wear many parts.

[0006] An object of the present disclosure is to provide, for example, an assistive force generation device and a motion assist device that are capable of changing the assistive force using only a mechanical configuration. [Means for solving the problem]

[0007] In order to achieve the above object, an auxiliary force generating device that is one aspect of the present disclosure includes a base portion on which a rotating shaft is provided, an elastic body attached to the base portion and including a first end and a second end fixed to the rotating shaft, and an auxiliary force changing mechanism connected to the first end and capable of changing the position of the first end relative to the second end, wherein the auxiliary force changing mechanism has a rotor that is rotatable about a rotation axis relative to the base portion and includes an eccentric shaft provided at a position away from the rotation axis, and a link that includes a first link end and a second link end, wherein the first link end is rotatably connected to the eccentric shaft and the first end is supported by the second link end, and the position of the first end relative to the second end can be changed by movement of the link accompanying the rotation of the rotor.

[0008] According to this assist force generating device, the assist force can be changed using only a mechanical configuration, without using an electrical configuration such as a drive motor.

[0009] In the above-described assisting force generating device, the position of the first end relative to the second end can be located at a first position and a second position different from the first position due to movement of the link accompanying rotation of the rotor, the rotor has a first abutment portion and a second abutment portion provided at different positions in the circumferential direction of the rotor, the assisting force change mechanism further has a stopper that stops rotation of the rotor, and when the first end is at the first position, the eccentric shaft is located on the side of the first area where the second end is present, of a first area and a second area of ​​the rotor that are separated by a line connecting a portion of the second link end that supports the first end and the rotation axis, and the first abutment portion of the rotor abuts against the stopper, stopping the rotation of the rotor, and when the first end is at the second position, the eccentric shaft is located on the side of the second area of ​​the rotor, and the second abutment portion of the rotor abuts against the stopper, stopping the rotation of the rotor. According to this assist force generating device, the assist force can be changed with only a simple mechanical configuration.

[0010] In the above-described assistive force generating device, the assistive force change mechanism may further include a first spring end connected to the connection portion of the base portion, a second spring end connected to the rotor, and an assist spring that expands and contracts with rotation of the rotor and pulls the portion of the rotor to which the second spring end is connected toward the connection portion, wherein the tensile force of the assist spring maintains a state in which the first abutment portion abuts against the stopper and a state in which the second abutment portion abuts against the stopper. This assistive force generating device can maintain the position of the first end changed by the assistive force change mechanism.

[0011] In the above assisting force generating device, the tensile force of the assist spring may be greater when the rotor is rotating and the first end is moving than when the rotor is stopped and the first end is at the first position and the second position. This assisting force generating device can prevent the moving first end from stopping at an intermediate position, and can move the first end to either the first position or the second position.

[0012] A motion-assist device according to one aspect of the present disclosure includes the above-described assist force generation device. This motion-assist device can change the assist force using only a mechanical configuration, without using an electrical configuration such as a drive motor. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view of a motion assist device according to an embodiment. [Figure 2] FIG. 2 is a perspective view of the internal structure of the drive unit shown in FIG. [Figure 3] 3 is a front view of the internal structure of the drive unit shown in FIG. 2, showing a state in which the assist force is weak. [Figure 4] FIG. 3 is a side view of the internal structure of the drive unit shown in FIG. 2. [Figure 5] 4 is a perspective view of the internal structure of the drive unit shown in FIG. 3, showing a state in which the assist force is weak. FIG. [Figure 6] FIG. 4 is a front view of the internal structure of the drive unit shown in FIG. 3, showing a state in which the assist force is strong. [Figure 7] 4 is a perspective view of the internal structure of the drive unit shown in FIG. 3, showing a state in which the assist force is strong. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An assist force generating device and a motion assist device according to an embodiment of the present disclosure will be described below. The motion assist device including the assist force generating device assists a user in a motion to raise their upper body.

[0015] FIG. 1 is a perspective view of a motion-assist device. The motion-assist device 1 includes an upper part 10 worn by a user on the upper body, a pair of drive units 20, and a pair of lower limb units 30. In FIG. 1, the chest support unit 12 side relative to the back support unit 11 is referred to as the front side, the back support unit 11 side relative to the chest support unit 12 is referred to as the rear side, the upper part 10 side relative to the drive units 20 is referred to as the upper side, and the lower limb units 30 side relative to the drive units 20 is referred to as the lower side. The direction in which the pair of drive units 20 face each other is referred to as the left-right direction. In FIG. 1, the postures of the upper part 10 and the lower limb units 30 relative to the drive units 20 are shown when a user wearing the motion-assist device 1 is standing upright.

[0016] The upper part 10 has a back support part 11, a chest support part 12, upper frames 13A and 13B, and a waist fixing member 14.

[0017] The back support portion 11 is a member that comes into contact with the back of the user when the device is worn. The surface of the back support portion 11 that comes into contact with the back of the user, i.e., the surface on the front side of the action-assist device 1, is made of a soft elastic material. The shape of the back support portion 11 is not limited to the form shown in the drawings.

[0018] The chest part 12 is a member that is worn on the chest of the user. The chest part 12 has a pair of strap-shaped members made of a soft, elastic material so that it can deform in response to the user's movements. Buckles 12A, for example, are provided on both ends of the front side of the chest part 12. The pair of strap-shaped members are connected to each other by the buckles 12A, thereby holding the chest part 12 in a cylindrical shape. The inner circumference of the chest part 12 is adjustable, allowing the chest part 12 to be properly fitted against the user's chest.

[0019] Upper frames 13A and 13B are members that connect the pair of drive units 20, the back support unit 11, and the chest support unit 12 to each other. Upper frames 13A and 13B are formed by bending a rod material such as a hollow round bar. Upper frames 13A and 13B are rigid bodies that fix the relative positions of the pair of drive units 20, the back support unit 11, and the chest support unit 12.

[0020] The upper frame 13A is provided on the back side of the backrest 11. The backrest 11 and the pair of upper frames 13B are fixed to the upper frame 13A. Each upper frame 13B is a member that extends above and below the backrest 11, and its lower end is connected to the upper end of the drive unit 20. The belt-shaped members of the chest rest 12 are connected to the upper ends of the pair of upper frames 13B, respectively.

[0021] The waist fixing member 14 is a single belt-shaped member and is connected to a pair of drive units 20. Buckles 14A, for example, are provided on both ends of the front side of the waist fixing member 14, and the waist fixing member 14 is held in a cylindrical shape by the buckles 14A. The inner circumferential length of the waist fixing member 14 is adjustable, allowing the waist fixing member 14 to be appropriately abutted against the waist of the user. The waist fixing member 14 is a soft member that can deform in accordance with the user's movements, allowing the user to move easily.

[0022] The pair of lower leg units 30 are shaped as a whole to roughly fit the user's thighs. Each lower leg unit 30 has a lower leg plate 31, a shaft 32, a lower leg arm 33, and a thigh pad 34. The lower leg plate 31 is fixed to a rotation shaft 25 (see FIG. 2) provided in the drive unit 20 and is rotatable together with the rotation shaft 25. The shaft 32 is provided at the lower end of the lower leg plate 31. The lower leg arm 33 is rotatably connected to the shaft 32. The lower leg arm 33 can be rotated by the shaft 32 to move towards and away from the user's thighs.

[0023] Each thigh pad 34 is a curved member that covers the front side of the user's thigh. Each thigh pad 34 is provided at the tip of each lower leg arm 33. When the user brings each thigh pad 34 into contact with the front side of the user's thigh, the movement of the thigh is transmitted to each drive unit 20.

[0024] Next, the drive unit 20 will be described. For example, the drive unit 20 corresponds to an assisting force generating device. Figures 2, 3, and 4 are a perspective view, a front view, and a side view of the internal structure of the drive unit 20 shown in Figure 1. Figures 3 and 4 show the drive unit 20 in a weak assisting force state. The drive unit 20 includes a case 21, a pair of base portions 22A and 22B, a connecting portion 23, a plurality of support columns 24, a rotating shaft 25, an elastic body 26, and an assisting force changing mechanism 40. The base portion 22A is not shown in Figure 3.

[0025] As shown in FIG. 1, waist fixation member 14 is rotatably mounted on rotating shaft 25 attached to case 21. As a result, drive unit 20 is held near the user's waist when waist fixation member 14 is attached to the user's waist. As shown in FIGS. 2-4, base portions 22A and 22B are generally flat and face each other with gap 22c between them. The lower end of upper frame 13B is connected to the upper end of base portion 22B by connecting portion 23. Gap 22c is formed by a plurality of (e.g., five) support columns 24 provided between the pair of base portions 22A and 22B. Connecting portion 23, rotating shaft 25, elastic body 26, and assist force change mechanism 40 are arranged in gap 22c.

[0026] Four support pillars 24 are provided around the assist force change mechanism 40 above the elastic body 26, and one support pillar 24 is provided below the elastic body 26. Each support pillar 24 has a cylindrical portion and a bolt, and the bolt is inserted into the pair of base portions 22A, 22B and screwed into the cylindrical portion, thereby fixing each support pillar 24 to the pair of base portions 22A, 22B. A shaft support hole (not shown) is formed in each of the base portions 22A, 22B. The rotating shaft 25 is inserted into the shaft support hole (not shown) of each of the base portions 22A, 22B, and is supported rotatably relative to the base portions 22A, 22B.

[0027] The elastic body 26 includes a first end 26A and a second end 26B and is formed by a spiral spring formed by winding a plate-like member without contact. The first end 26A, which is the outer end of the elastic body 26, is supported by a link 43 (described later) of the assist force change mechanism 40, and the second end 26B, which is the inner end of the elastic body 26, is fixed to the rotation shaft 25. The spiral spring, which is the elastic body 26, is wound counterclockwise from the first end 26A to the second end 26B located in the center, as viewed from the base portion 22A side. Therefore, by winding the elastic body 26 so that the second end 26B rotates counterclockwise while keeping the posture of the first end 26A of the elastic body 26 fixed, a force (biasing force) that rotates the elastic body 26 in the opposite direction (clockwise) is generated. This biasing force assists the user's waist movement when returning the user's posture from bending forward to an upright position. The first end 26A is curved outward and has a recess.

[0028] The assist force change mechanism 40 has an operation knob 41, a rotor 42, a link 43, a pair of stop shafts 45, and an assist spring 46. The assist force change mechanism 40 functions like a crank mechanism, and converts the rotational motion of the rotor 42 into translational motion of the first end 26A of the elastic body 26.

[0029] The operation knob 41 is provided on the outer surface of the case 21 and is rotatable around its rotation axis 41A. The rotation axis 41A penetrates the case 21. The operation knob 41 and the rotor 42 are provided at positions facing the recessed portion of the first end 26A in the circumferential direction centered on the rotary shaft 25. The rotor 42 has a pair of rotation plates 42A and an eccentric shaft 42B. Each rotation plate 42A is a substantially fan-shaped flat plate and is rotatably supported on each of the base portions 22A and 22B. Each rotation plate 42A has a first abutment portion 42C and a second abutment portion 42D located at both ends in the circumferential direction. The rotation plate 42A located on the operation knob 41 side is connected to the rotation axis 41A and rotates with the rotation of the operation knob 41. The rotation axis of the rotation plate 42A provided on the base portion 22B is located on the axis of the rotation axis 41A. The pair of rotating plates 42A are connected to each other by an eccentric shaft 42B. As a result, when the operation knob 41 is rotated, the entire rotor 42 rotates around the rotation axis 41A. The eccentric shaft 42B is disposed at a position separated from the rotation axis of the rotating plates 42A. The eccentric shaft 42B corresponds to, for example, an eccentric shaft.

[0030] The link 43 has a pair of link plates 43A and a pair of support shafts 44. The link plate 43A has a first link end 43B and a second link end 43C. The first link end 43B is located on the outer surface side of each rotating plate 42A and is rotatably connected to the eccentric shaft 42B of the rotor 42. Therefore, the rotation axis of each first link end 43B is eccentric from the rotation axis of the rotating plate 42A. The second link end 43C of each link plate 43A is connected to each other by a pair of support shafts 44. The first end 26A is sandwiched between the pair of support shafts 44. The second link end 43C supports the first end 26A.

[0031] The pair of stop shafts 45 are provided on opposite sides of the first end 26A of the operation knob 41. The stop shafts 45 extend toward each other from the respective base portions 22A and 22B, with a gap 45a formed between them. Each stop shaft 45 extends to at least the same position as the respective rotary plate 42A in the axial direction of the rotary shaft 41A. Each stop shaft 45 has a cylindrical portion and a bolt. The bolt is inserted into each base portion 22A and 22B and screwed into the cylindrical portion, thereby fixing each stop shaft 45 to each base portion 22A and 22B. The first spring end 46A of the assist spring 46 is connected to the support 24 located above the rotor 42, and the second spring end 46B is connected to the eccentric shaft 42B. The assist spring 46 constantly pulls the eccentric shaft 42B toward the support 24 located above the rotor 42. The support 24 to which the first spring end 46A is connected corresponds to, for example, a connection portion. The pair of stop shafts 45 corresponds to, for example, a stopper.

[0032] Next, the operation of changing the assisting force by the assisting force change mechanism 40 will be described with reference to Figures 3 and 5-7. Figure 5 is a perspective view of the internal structure of the drive unit 20 shown in Figure 3, showing a weak assisting force state. Figures 6 and 7 are a front view and a perspective view of the internal structure of the drive unit 20 shown in Figure 3, showing a strong assisting force state.

[0033] The first position is the position of the first end 26A of the elastic body 26 shown in Figures 3 and 5. The rotor 42 is divided into a first region T1 and a second region T2, which are separated by a line L connecting the portion of the second link end 43C supporting the first end 26A and the rotation shaft 41A. The second end 26B of the elastic body 26, which is the origin of the force acting on the first end 26A, is located on the first region T1 side. The rotor 42 receives the elastic force of the elastic body 26 via the link 43 and the eccentric shaft 42B and attempts to rotate clockwise in Figure 3. Because the first contact portion 42C of the rotor 42 contacts the stop shaft 45, the rotor 42 is stopped from rotating. The tension of the assist spring 46 maintains the first contact portion 42C in contact with the stop shaft 45. As shown in Figure 5, the assist spring 46 is located within the gap 45a.

[0034] To change the assist force of the drive unit 20, the user rotates the operation knob 41 counterclockwise, which rotates the rotor 42 counterclockwise until the second abutment portion 42D abuts the stop shaft 45. The link 43 moves as the rotor 42 rotates. The first end 26A of the elastic body 26 shown in FIGS. 6 and 7 is in a second position different from the first position. The eccentric shaft 42B is located on the second region T2 side of the rotor 42. The rotor 42 receives the elastic force of the elastic body 26 via the link 43 and the eccentric shaft 42B and attempts to rotate counterclockwise in FIG. 6. Because the second abutment portion 42D of the rotor 42 abuts the stop shaft 45, the rotation of the rotor 42 is stopped. The tension of the assist spring 46 maintains the second abutment portion 42D abutting the stop shaft 45.

[0035] The initial tightening angle of the elastic body 26 shown in Figures 6 and 7 is larger than the initial tightening angle of the elastic body 26 shown in Figures 3 and 5. The assisting force of the drive unit 20 shown in Figures 3 and 5 is in a weak state, and the assisting force of the drive unit 20 shown in Figures 6 and 7 is in a strong state. In this way, the user can change the assisting force of the drive unit 20 from a weak state to a strong state by rotating the operation knob 41 counterclockwise in the state shown in Figures 3 and 5 until the second abutment portion 42D abuts the stop shaft 45. Similarly, the user can change the assisting force of the drive unit 20 from a strong state to a weak state by rotating the operation knob 41 clockwise in the state shown in Figures 6 and 7 until the first abutment portion 42C abuts the stop shaft 45. Specifically, line L is a line connecting the bottom of the recess in first end 26A and the rotating shaft 41A, and can also be said to be a line connecting the portion of second link end 43C where the force supporting first end 26A is applied (the central axis of support shaft 44) and the rotating shaft 41A.

[0036] When a user wearing the action-assist device 1 bends their knees slightly and leans their upper body forward from an upright position, the upper part 10 and the drive unit 20 rotate around the rotation shaft 25 relative to the lower limbs 30. By winding the elastic body 26 so that the outer end rotates while keeping the position of the second end 26B of the elastic body 26 fixed, a force (assist force) that rotates in the opposite direction is generated in the elastic body 26. This assist force becomes a torque (assist torque) that assists the movement of the waist when the user returns the waist posture from bending forward to an upright position. The greater the angle at which the user leans their upper body, the greater the assist torque.

[0037] The present disclosure is not limited to the configuration of the above-described embodiment. The present disclosure, as defined by the claims, is not limited to the above-described embodiment, but is intended to include all modifications within the meaning and scope equivalent to the claims. For example, in the above-described embodiment, a spiral spring is used as the elastic body 26. The form of the elastic body is not limited to this.

Claims

1. An auxiliary force generating device (20), a base portion (22A, 22B) provided with a rotating shaft (25); an elastic body (26) attached to the base portion (22A, 22B) and including a first end (26A) and a second end (26B) fixed to the rotating shaft (25); an assist force change mechanism (40) connected to the first end (26A) and capable of changing the position of the first end (26A) relative to the second end (26B); The assist force change mechanism (40) a rotor (42) that is rotatable about a rotation axis (41A) relative to the base portion (22A, 22B) and includes an eccentric shaft (42B) that is provided at a position away from the rotation axis (41A); a link (43) including a first link end (43B) and a second link end (43C), the first link end (43B) being rotatably connected to the eccentric shaft (42B), and the first end (26A) being supported by the second link end (43C); The position of the first end (26A) relative to the second end (26B) can be changed by movement of the link (43) accompanying rotation of the rotor (42). Auxiliary force generating device (20).

2. the first end (26A) relative to the second end (26B) can be positioned at a first position and a second position different from the first position by movement of the link (43) accompanying rotation of the rotor (42); The rotor (42) has a first contact portion (42C) and a second contact portion (42D) provided at different positions in the circumferential direction of the rotor (42), The assist force change mechanism (40) further includes a stopper (45) that stops the rotation of the rotor (42), When the first end (26A) is in the first position, the eccentric shaft (42B) is located on the first region (T1) side where the second end (26B) is present, out of a first region (T1) and a second region (T2) of the rotor (42) that are separated by a line (L) connecting a portion of the second link end (43C) that supports the first end (26A) and the rotation shaft (41A), and the first abutment portion (42C) of the rotor (42) abuts against the stopper (45), stopping the rotation of the rotor (42).

2. An auxiliary force generating device (20) as described in claim 1, wherein, when the first end (26A) is in the second position, the eccentric shaft (42B) is located on the second region (T2) side of the rotor (42), and the second abutment portion (42D) of the rotor (42) abuts against the stopper (45), stopping the rotation of the rotor (42).

3. The assist force change mechanism (40) a first spring end (46A) connected to the connection portion (24) of the base portion (22A, 22B); a second spring end (46B) connected to the rotor (42); an assist spring (46) that expands and contracts with the rotation of the rotor (42) and pulls the portion of the rotor (42) to which the second spring end (46B) is connected toward the connection portion (24), An auxiliary force generating device (20) as described in claim 1 or claim 2, wherein the tensile force of the assist spring (46) maintains the first abutment portion (42C) in contact with the stopper (45) and the second abutment portion (42D) in contact with the stopper (45).

4. 4. An assisting force generating device (20) as described in claim 3, wherein the tensile force of the assist spring (46) is greater when the rotor (42) is rotating and the first end (26A) is moving than when the rotor (42) is stopped and the first end (26A) is at the first position and the second position.

5. A motion assisting device (1) comprising an assisting force generating device (20) according to any one of claims 1 to 4.

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