Biasing force generation device and operation assistance apparatus

Abstract

To provide a biasing force generation device and an operation assistance apparatus from which a spiral spring can be detached.SOLUTION: A biasing force generation device 20 includes a base part (41, 42) provided with a rotary shaft portion 47, and a spiral spring cassette 60 which has a cassette (61, 62) that accommodates a spiral spring 65 having a central portion 65B and an outer end portion 65A and is detachably attachable to the base part (41, 42). When the rotary shaft portion 47 rotates relative to the base part (41, 42), the outer end portion 65A is supported by the cassette (61, 62), and the central portion 65B is wound by rotation of the rotary shaft portion 47 so that the spiral spring 65 is tightened to generate the biasing force.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a biasing force generating device and a motion assisting device. [Background technology]

[0002] Patent Document 1 discloses a motion-assist suit in which a belt is integrally connected to the jacket, pneumatic artificial muscles are arranged vertically on the back side of the jacket, and the artificial muscles contract when air is supplied, pulling the belt. The artificial muscles can be removed from the jacket by disconnecting the first and second connecting parts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6760602 Summary of the Invention [Problem to be solved by the invention]

[0004] In the motion assistance suit of Patent Document 1, the source of the assisting force is a pneumatic artificial muscle unit. Even in the biasing force generating device where the source of the assisting force is a spiral spring, the spiral spring can be removed. A device is required.

[0005] An object of the present disclosure is to provide, for example, a biasing force generating device and an action assisting device in which the spiral spring is removable. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present disclosure provides a biasing force generator including a base portion provided with a rotating shaft portion, and a power spring cassette having a cassette accommodating a power spring having a center portion and an outer end portion, the power spring cassette being removably attached to the base portion. The biasing force generator is configured such that, when the rotating shaft portion rotates relative to the base portion, the outer end portion is supported by the cassette, and the center portion is wound by rotation of the rotating shaft portion, thereby tightening the power spring and generating a biasing force.

[0007] According to this biasing force generator, the spiral spring can be easily removed from the biasing force generator. This allows the spiral spring cassette to be easily replaced if the spiral spring is damaged. Furthermore, the already installed spiral spring can be replaced with a stronger spiral spring, and the spiral spring cassette can be increased or decreased. This allows the user to easily change the assist force and biasing force.

[0008] In the above-described biasing force generator, the rotating shaft may have a rotating shaft extending toward the spiral spring cassette, and when the spiral spring cassette is attached to the base, the rotating shaft is located around the center portion, and when the rotating shaft rotates around the central axis of the rotating shaft, the center portion is wound by the rotation of the rotating shaft. According to this biasing force generator, the spiral spring cassette can be easily removed from the rotating shaft by pulling it out.

[0009] In the above-described biasing force generator, the base portion may be provided with a retaining shaft extending toward the spiral spring cassette, the cassette may have a retaining hole formed therein, and the retaining shaft may pass through the retaining hole to attach the spiral spring cassette to the base portion. According to this biasing force generator, the spiral spring cassette can be easily attached to the base portion by inserting the retaining shaft into the retaining hole of the cassette, and the spiral spring cassette can be easily removed from the base portion by removing the retaining shaft from the retaining hole of the cassette.

[0010] In the above-described biasing force generator, the spiral spring cassette is a first spiral spring cassette, and a second spiral spring cassette may be further provided, and the first spiral spring cassette and the second spiral spring cassette may be attached to the base portion in an overlapping state. With this biasing force generator, the biasing force (assistance force) can be easily increased or decreased.

[0011] The above-mentioned biasing force generator may further include a lock plate removably attached to the base portion and locked to the base portion, the lock plate being attached to the outside of the first spiral spring cassette and the second spiral spring cassette. This biasing force generator can prevent the spiral spring cassettes from coming off the base portion.

[0012] In order to achieve the above object, a motion-assist device according to one aspect of the present disclosure includes any one of the above-described biasing force generators. With this motion-assist device, the spiral spring can be easily removed from the biasing force generator. This makes it possible to easily replace the spiral spring cassette if the spiral spring is damaged. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view of an action assist device according to an embodiment. [Figure 2] 2 is an exploded perspective view of the cassette holding section of FIG. 1 with a biasing force generating section removed. FIG. [Figure 3] 3 is an exploded perspective view of the cassette holding portion and the lower leg portion of FIG. 2. FIG. [Figure 4] FIG. 3 is an exploded perspective view of the spiral spring cassette of FIG. 2. [Figure 5] 3 is an explanatory diagram of a method for attaching a biasing force generator to the cassette holding portion of FIG. 2. FIG. [Figure 6] FIG. 10 is a perspective view of a spiral spring cassette according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0014] The following describes a biasing force generating device and a motion-assist device according to an embodiment of the present disclosure. The motion-assist device assists a user in raising their upper body (stretching their waist). FIG. 1 is a perspective view of the motion-assist device 1. The posture of the upper part 10 and the lower limb part 30 relative to the drive unit 20 in FIG. 1 is the posture when a user wearing the motion-assist device 1 is standing upright. In the following description, for the sake of simplicity, when a component is made up of parts, a reference symbol may be assigned to only one part.

[0015] The action-assist device 1 includes an upper part 10 worn by a user, a pair of drive units 20, and a pair of lower limb parts 30. In the following description, the shoulder belt 12 side relative to the backrest 11 is referred to as the front side, the backrest 11 side relative to the shoulder belt 12 is referred to as the rear side, the upper part 10 side relative to the drive unit 20 is referred to as the upper side, and the lower limb parts 30 side relative to the drive unit 20 is referred to as the lower side. In Fig. 1, the postures of the upper part 10 and the lower limb parts 30 relative to the drive unit 20 are shown when the user wearing the action-assist device 1 is standing upright.

[0016] The upper part 10 has a back support part 11, a pair of shoulder belts 12, a pair of upper frames 13, a pair of belt plates 14, a waist belt 15, and a hip belt 16.

[0017] The back support portion 11 is flat and comes into contact with the back of the user when 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 pair of shoulder belts 12 are members that are worn on the shoulders of the user. Each shoulder belt 12 is a belt-shaped member made of a soft material so that it can deform to follow the user's movements. The pair of shoulder belts 12 are each connected to the backrest portion 11. The upper end of the right shoulder belt 12 is connected to the upper end of the right side of the backrest portion 11. The lower end of the right shoulder belt 12 is connected to the lower end of the right side of the backrest portion 11. The upper end of the left shoulder belt 12 is connected to the upper end of the left side of the backrest portion 11. The lower end of the left shoulder belt 12 is connected to the lower end of the left side of the backrest portion 11. The length of each shoulder belt 12 is adjustable.

[0019] The pair of upper frames 13 are members that connect the pair of drive units 20 and the backrest portion 11 to each other. Each upper frame 13 is formed by bending a rod material such as a hollow round bar. Each upper frame 13 is a rigid body and fixes the relative positional relationship between the pair of drive units 20 and the backrest portion 11. The upper end of each upper frame 13 is connected to the backrest portion 11. Each upper frame 13 extends downward and outward from its upper end. The lower end of each upper frame 13 is connected to the upper end of the drive unit 20.

[0020] The pair of belt plates 14 are plate-shaped members that are positioned on either side of the user's waist when worn. As shown in FIG. 3, a first through-hole 14a is formed in the lower portion of the belt plate 14. A protruding portion 47B of a rotating shaft 47 (described below) is inserted into the first through-hole 14a. The inserted protruding portion 47B of the rotating shaft 47 is rotatably supported with respect to the belt plate 14 by a plurality of support members 14B.

[0021] As shown in FIG. 1, the waist belt 15 is a single belt-like member and is fixed to a pair of belt plates 14. Buckles 15A, for example, are provided on both ends of the front side of the waist belt 15. The waist belt 15 is held in a tubular shape by the buckles 15A. The length of the waist belt 15 is adjustable. By adjusting the length of the waist belt 15, the waist belt 15 can be appropriately fitted to the waist of the user. The waist belt 15 is made of a soft member and can deform in accordance with the user's movements, allowing the user to move easily.

[0022] The hip belt 16 is a single belt-shaped member and is fixed to a pair of belt plates 14. The length of the hip belt 16 is adjustable. By adjusting the length of the hip belt 16, the hip belt 16 comes into proper contact with the user's buttocks. The hip belt 16 is a soft member and can deform in accordance with the user's movements, allowing the user to move easily.

[0023] Next, the pair of lower leg units 30 will be described in detail with reference to FIGS. 1-3. FIG. 2 is an exploded perspective view of the cassette holding unit 40 of FIG. 1 with the biasing force generating unit 50 removed. FIG. 3 is an exploded perspective view of the cassette holding unit 40 and the lower leg units 30 of FIG. 2. The pair of lower leg units 30 have a symmetrical configuration, so the configuration of the pair of lower leg units 30 will be described focusing on one lower leg unit 30 (the lower leg unit 30 on the left side of FIG. 1). The lower leg units 30 as a whole have a shape that generally conforms to the user's thighs. As shown in FIGS. 1 and 3, each lower leg unit 30 has a first connecting member 31, a second connecting member 32, a hinge 33, a lower leg frame 34, and a thigh pad 35.

[0024] As shown in FIG. 3, the first connecting member 31 extends in a direction inclined relative to the vertical direction, and its cross section is U-shaped with corners at approximately right angles. A plurality of first screw insertion holes 31a and a plurality of first shaft through holes 31b are formed in the bottom of the first connecting member 31. Although only a portion is shown in FIG. 3, there are four first screw insertion holes 31a and four first shaft through holes 31b, which are arranged alternately in a substantially circular pattern. A plurality of second screw insertion holes 31c are formed in the side of the first connecting member 31. An insertion hole 31d is formed in the lower end of the side of the first connecting member 31.

[0025] The second connecting member 32 extends in a direction inclined with respect to the vertical direction and has a U-shaped cross section. A plurality of third screw insertion holes 32a and a plurality of second shaft through holes 32b are formed in the bottom of the second connecting member 32. Four third screw insertion holes 32a and four second shaft through holes 32b are formed, and they are arranged alternately in a substantially circular shape. A plurality of first screw holes 32c are formed in the side of the second connecting member 32. With the second connecting member 32 inserted into the first connecting member 31, a plurality of screws 36 are inserted into each of the second screw insertion holes 31c and screwed into each of the first screw holes 32c, thereby fixing the second connecting member 32 to the first connecting member 31.

[0026] The hinge 33 is connected to the first connecting member 31 so as to be rotatable around the rotation shaft. Therefore, the hinge 33 is connected to the first connecting member 31 so as to be rotatable in the leg-spreading direction. The lower leg frame 34 is shaped to extend from the hinge 33 to the front of the user's thighs when in use. The thigh pad 35 is a curved member that covers the front of the user's thighs. The thigh pad 35 is provided at the tip of the lower leg frame 34. When the user abuts the thigh pad 35 against the front of the user's thighs, the movement of the thighs is transmitted to the drive unit 20 via the lower leg frame 34, the hinge 33, the first connecting member 31, and the second connecting member 32. As a result, the rotation shaft 47 (described later) rotates, and the mainspring screw 65 (described later) is wound, generating a biasing force.

[0027] Next, the drive unit 20 will be described with reference to Figures 2-5. For example, the drive unit 20 corresponds to the biasing force generator. Figure 4 is an exploded perspective view of the spiral spring cassette of Figure 2. Figure 5 is an explanatory diagram of a method for attaching the biasing force generator to the cassette holding part of Figure 2.

[0028] As shown in Fig. 2, the drive unit 20 has a cassette holding section 40 and a biasing force generating section 50. As shown in Fig. 3, the cassette holding section 40 has a first base member 41, a second base member 42, a spacer 43, a connecting member 44A, a first bearing 45, a second bearing 46, a rotating shaft section 47, and a first shaft support member 48.

[0029] The first base member 41 and the second base member 42 are each substantially flat and face each other with a gap therebetween. The gap is formed by a spacer 43 provided between the first base member 41 and the second base member 42. A first bearing 45, a second bearing 46, a rotating shaft portion 47, a first shaft support member 48, a first connecting member 31, and a second connecting member 32 are arranged in the gap. The spacer 43 is fixed to the first base member 41 and the second base member 42 by a plurality of screws 43A and 43B. The first base member 41 and the second base member 42 correspond to, for example, base portions.

[0030] The lower end of the upper frame 13 is fixedly connected to the upper end of the first base member 41 by a connecting member 44A and a plurality of screws 44B. A second through hole 41a is formed in the first base member 41. A third through hole 42a is formed in the second base member 42. Six holding shafts 42B are provided on the outer surface of the second base member 42. The six holding shafts 42B are arranged two by two adjacent shafts to form a triangle. Three annular locking grooves 42c are formed in each holding shaft 42B. A first bearing 45 is fitted into the second through hole 41a of the first base member 41. A second bearing 46 is fitted into the third through hole 42a of the second base member 42.

[0031] The rotating shaft portion 47 has a base portion 47A, a protruding portion 47B, and four rotating shafts 47C. The base portion 47A is generally disk-shaped and is attached to the first bearing 45. The rotating shaft portion 47 is rotatable relative to the first base member 41 via the first bearing 45. A plurality of second screw holes 47d are formed in the base portion 47A. The second screw holes 47d correspond to the first screw insertion holes 31a of the first connecting member. A plurality of screws 47E are threaded into the second screw holes 47d via the first screw insertion holes 31a. This fixes the rotating shaft portion 47 to the first connecting member 31.

[0032] The protruding portion 47B protrudes from the base portion 47A toward the belt plate 14. The protruding portion 47B is inserted into the first through-hole 14a of the belt plate 14 and is rotatably supported with respect to the belt plate 14 by a plurality of support members 14B. The four rotating shafts 47C extend outward from the base portion 47A. As shown in FIG. 2, the rotating shafts 47C pass through the first shaft through-hole 31b, the second shaft through-hole 32b, and a third shaft through-hole 48b (described later), and protrude outward from the second base member 42.

[0033] As shown in FIG. 3 , the first shaft support member 48 is generally disk-shaped and is attached to the second bearing 46. The first shaft support member 48 is rotatable relative to the second base member 42 via the second bearing 46. A plurality of third screw holes 48a and a plurality of third shaft through holes 48b are formed in the first shaft support member 48. Four third screw holes 48a and four third shaft through holes 48b are formed, and they are alternately arranged in a generally circular pattern. A plurality of screws 48C are threadedly engaged with the plurality of third screw holes 48a via the plurality of third screw insertion holes 32a. This fixes the first shaft support member 48 to the connecting member 32.

[0034] With this configuration, when the first connecting member 31 and the second connecting member 32 rotate around the rotation shaft portion 47, the rotation shaft portion 47 also rotates around its axis. As a result, the four rotating shafts 47C of the rotation shaft portion 47 rotate around the central axis of the rotation shaft portion 47.

[0035] As shown in FIG. 2, the biasing force generating unit 50 has a plurality of spiral spring cassettes 60 and a lock plate 51. In this embodiment, three spiral spring cassettes 60 are provided stacked one on top of the other. All three spiral spring cassettes 60 have the same configuration. The innermost spiral spring cassette 60 corresponds to, for example, a first spiral spring cassette, and the middle spiral spring cassette 60 corresponds to, for example, a second spiral spring cassette.

[0036] 4, the spiral spring cassette 60 includes a case 61, a cover 62, a third bearing 63, a fourth bearing 64, a spiral spring 65, an outer end support member 66, a pair of inner end support members 67, a second shaft support member 68, and a third shaft support member 69. The case 61 and the cover 62 correspond to, for example, a cassette.

[0037] The case 61 has a bottom surface portion 61A and a side surface portion 61B. The bottom surface portion 61A is generally triangular in shape. A fourth through hole 61c is formed in the bottom surface portion 61A. The side surface portion 61B is provided on the periphery of the bottom surface portion 61A. A notch 61d is formed in each of the three corners of the side surface portion 61B. Two first retaining holes 61e are formed in two corners of the side surface portion 61B, each on either side of the notch 61d. An oval-shaped second retaining hole (not shown) is formed in the bottom surface portion 61A near the remaining corner of the side surface portion 61B. A fourth screw hole 61f is formed in each of the notches 61d.

[0038] The cover 62 has a substantially triangular shape. A fifth through hole 62a is formed in the cover 62. Fixing portions 62B that protrude toward the case 61 are provided at three corners of the cover 62. Two third retaining holes 62c are formed in two corners of the cover 62, each sandwiching a fixing portion 62B. An oval fourth retaining hole 62d is formed in the remaining corner of the cover 62. A fourth screw insertion hole 62e is formed in each fixing portion 62B. The cover 62 is fixed to the case 61 so as to cover its opening. The three fixing portions 62B of the cover 62 are inserted into the three notches 61d of the case 61. Each fixing portion 62B is fixed to the side surface portion 61B of the case 61 by a bolt 62F. When the cover 62 is attached to the case 61, the third retaining holes 62c face the first retaining holes 61e and communicate with each other, and the fourth retaining hole 62d faces the second shaft support hole (not shown). The third bearing 63 is fitted into the fourth through hole 61c of the case 61. The fourth bearing 64 is fitted into the fifth through hole 62a of the cover 62.

[0039] The power spring 65 is, for example, a spirally wound plate-like member. The power spring 65 is wound from its outer end 65A toward its center 65B. The outer end support member 66 has an elongated cylindrical shape. The outer end support member 66 is located between a second shaft support hole (not shown) of the case 61 and a fourth retaining hole 62d of the cover 62. The outer end support member 66 is fixed to the case 61 by threading a bolt 62F into a fifth screw hole 66a. Two fifth retaining holes 66b are formed in the outer end support member 66. The fifth retaining holes 66b communicate with the outside via the second shaft support hole (not shown) and the fourth retaining hole 62d. The outer end 65A of the power spring 65 is supported by the outer end support member 66.

[0040] Each inner end support member 67 has an elongated cylindrical shape. The pair of inner end support members 67 are arranged to sandwich the center portion 65B of the spiral spring 65. Two fourth shaft through holes 67a are formed in each inner end support member 67. A sixth screw hole 67b is formed between the two fourth shaft through holes 67a in each inner end support member 67. The second shaft support member 68 has a generally disk shape and is attached to the third bearing 63. The second shaft support member 68 is rotatable relative to the case 61 by the third bearing 63. A plurality of fifth shaft through holes 68a and a plurality of fifth screw insertion holes 68b are formed in the second shaft support member 68. Four fifth shaft through holes 68a are formed and two fifth screw insertion holes 68b are formed. The third shaft support member 69 has a generally disk shape and is attached to the fourth bearing 64. The third shaft support member 69 is rotatable relative to the cover 62 by the fourth bearing 64. A plurality of sixth shaft through holes 69a and a plurality of sixth screw insertion holes 69b are formed in the third shaft support member 69. Four sixth shaft through holes 69a are formed, and two sixth screw insertion holes 69b are formed.

[0041] The bolt 68C is inserted into one of the fifth screw insertion holes 68b and screwed into the sixth screw hole 67b of one of the inner end support members 67. This fixes the second shaft support member 68 to the inner end support member 67. The bolt 69C is inserted into one of the two sixth screw insertion holes 69b opposite the side into which the bolt 68C is inserted and screwed into the sixth screw hole 67b of the other inner end support member 67. This fixes the third shaft support member 69 to the inner end support member 67. As a result, the pair of inner end support members 67 are supported by the second shaft support member 68 and the third shaft support member 69 with the center portion 65B of the spiral spring 65 sandwiched between them. The fifth shaft through holes 68a, the fourth shaft through holes 67a, and the sixth shaft through holes 69a are aligned in a straight line along the axial direction of the rotating shaft portion 47.

[0042] As shown in FIG. 2, the lock plate 51 has a generally triangular shape. A sixth through hole 51a is formed in the lock plate 51. Two seventh retaining holes 51b are formed in each of the three corners of the lock plate 51. Three rod-shaped springs 51D are attached to the outer surface 51C of the lock plate 51. Each spring 51D extends along one side of the lock plate 51. An end of each spring 51D overlaps a portion of the outer edge of each seventh retaining hole 51b.

[0043] FIG. 5 is an explanatory diagram of a method for attaching the biasing force generator 50 to the cassette holding portion 40. As shown in the upper diagram of FIG. 5, when the rotating shaft 47C is inserted into the fourth, fifth shaft through-holes 67a, 68a and the sixth shaft through-hole 69a and the retaining shaft 42B is inserted into the first and fourth retaining holes 61e, 62d (see FIG. 4), the third retaining hole 62c and the fifth retaining hole 66b, the spiral spring cassette 60 is held by the cassette holding portion 40. As shown in the lower left diagram of FIG. 5, the spiral spring cassette 60 is similarly attached to the remaining two spiral spring cassettes 60 so as to overlap the remaining two spiral spring cassettes 60. As shown in the lower right diagram of FIG. 5, the retaining shaft 42B is inserted into the seventh retaining hole 51b of the lock plate 51, whereby the lock plate 51 is held by the cassette holding portion 40.

[0044] Because the end of spring 51D overlaps part of the outer edge of seventh retaining hole 51b, it is pressed against the outer peripheral surface of retaining shaft 42B when retaining shaft 42B passes through seventh retaining hole 51b. When lock plate 51 abuts against spiral spring cassette 60, the end of spring 51D fits into the locking groove 42c closest to the tip of the three locking grooves 42c of retaining shaft 42B. This prevents lock plate 51 from coming off retaining shaft 42B, and therefore prevents spiral spring cassette 60 from coming off retaining shaft 42B.

[0045] When removing the spiral spring cassette 60 from the cassette holding portion 40, first remove the lock plate 51 from the holding shaft 42B. Then, pull the spiral spring cassette 60 out of the holding shaft 42B and the rotating shaft 47C to remove the spiral spring cassette 60 from the cassette holding portion 40. In this manner, the spiral spring cassette 60 can be easily removed from the cassette holding portion 40. The biasing force (assistance force) can be easily increased or decreased by changing the number of spiral spring cassettes 60 attached to the cassette holding portion 40. When only one spiral spring cassette 60 is attached, the end of the spring 51D of the lock plate 51 fits into the locking groove 42c closest to the base end of the three locking grooves 42c. When only two spiral spring cassettes 60 are attached, the end of the spring 51D of the lock plate 51 fits into the middle locking groove 42c of the three locking grooves 42c.

[0046] When a user wearing the action-assist device 1 bends their knees slightly and leans their upper body forward from an upright position, the lower limbs 30 rotate around the rotating shafts 47 relative to the upper part 10 and the drive unit 20. At this time, the four rotating shafts 47C rotate around the central axis of the rotating shafts 47, causing the pair of inner-end support members 67 of each spiral spring cassette 60 to rotate. The pair of inner-end support members 67 winds the center portion 65B of the spiral spring 65, tightening the spiral spring 65, and a force (biasing force) that rotates the spiral spring 65 in the direction opposite to the rotation of the spiral spring 65 is generated. This biasing force becomes a torque (assisting torque, assisting force) that assists the movement of the waist when the user moves their waist from a bent-over position back to an upright position. The greater the angle at which the user leans their upper body, the greater the assisting torque.

[0047] The present disclosure is not limited to the configurations of the above-described embodiments. The aspects defined by the claims are not limited to the above-described embodiments, and are intended to include all modifications within the meaning and scope of the claims.

[0048] FIG. 6 is a perspective view of a spiral spring cassette 160 according to a modified example. The spiral spring cassette 160 has a structure in which three springs 51D of the lock plate 51 are attached to the spiral spring cassette 60 of the above-described embodiment. That is, the three springs 51D are attached to the outer surface of the cover 62. Each spring 51D extends along each side of the cover 62. The end of each spring 51D overlaps a portion of the outer edge of the corresponding third retaining hole 62c. When the spiral spring cassette 160 is attached to the cassette holder 40, the end of each spring 51D overlaps a portion of the outer edge of the corresponding third retaining hole 62c, so that the end of the spring 51D fits into the locking groove 42c of the retaining shaft 42B. This prevents the spiral spring cassette 160 from coming off the retaining shaft 42B. While the spiral spring 65 is a non-contact spiral spring in the embodiment, it may be a contact spiral spring.

Claims

1. A biasing force generating device (20), a base portion (41, 42) provided with a rotation shaft portion (47); a spiral spring cassette (60, 160) having a cassette (61, 62) containing a spiral spring (65) having a center portion (65B) and an outer end portion (65A), the spiral spring cassette (60, 160) being removably attached to the base portion (41, 42); When the rotating shaft portion (47) rotates relative to the base portion (41, 42), the outer end portion (65A) is supported by the cassette (61, 62), and the center portion (65B) is wound by the rotation of the rotating shaft portion (47), thereby tightening the spiral spring (65), and generating a biasing force.

2. The rotating shaft portion (47) has a rotating shaft (47C) extending toward the spiral spring cassette side, When the spiral spring cassette (60, 160) is attached to the base portion (41, 42), the rotating shaft is located around the center portion, 2. The biasing force generating device according to claim 1, wherein when the rotating shaft portion (47) rotates around the central axis, the center portion (65B) is wound by the rotation of the rotating shaft (47C).

3. The base portion (41, 42) is provided with a holding shaft (42B) extending toward the spiral spring cassette side, The cassettes (61, 62) are formed with holding holes (61e, 62c), 3. The biasing force generating device according to claim 1, wherein the spiral spring cassette is attached to the base by the retaining shaft passing through the retaining hole.

4. The spiral spring cassette (60) is a first spiral spring cassette (60) and further includes a second spiral spring cassette (60), 4. The biasing force generating device according to claim 1, wherein the first spiral spring cassette (60) and the second spiral spring cassette (60) are attached to the base portion (41, 42) in an overlapping state.

5. The vehicle further includes a lock plate (51) that is removably attached to the base portion (41, 42) and locked to the base portion (41, 42), 5. The biasing force generating device according to claim 4, wherein the lock plate (51) is attached to the outside of the first spiral spring cassette (60) and the second spiral spring cassette (60).

6. A motion assist device (1) comprising the biasing force generating device (20) according to any one of claims 1 to 5.

Images