Joint device

Abstract

To provide a joint device for enabling a connection part to be extended and bent by power of a power source.SOLUTION: An electric prothetic leg 1 includes: an under-knee member 110; an above-knee member 120; a knee joint mechanism 130 for connecting the under-knee member 110 to the above-knee member 120 to enable an angle made by the members to be changeable; and an extension / contraction device 140 for enabling the angle made by the under-knee member 110 and the above-knee member 120 to be exchangeable by extending / contracting. The extension / contraction device 140 includes: a motor M; and a transmission T for transmitting power of the motor M. The transmission T includes: a first transmission mechanism T1 for transmitting the power of the motor M by a first transmission gear ratio; and a second transmission mechanism T2 for transmitting the power of the motor M by a second transmission gear ratio different from the first transmission gear ratio.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, a known joint device used in a joint connecting two members includes an extension device that can change the angle between the two members. One example of such a joint device is a prosthetic leg used in a knee joint. Patent Document 1 describes a method in which a sensor that detects the contraction movement of the muscles in the stump of the amputated leg is provided in the femoral socket of the prosthetic leg attached to the stump of the amputated leg, and the throttle of a variable valve of a hydraulic cylinder that adjusts the resistance of flexion and extension of the knee joint is controlled based on the detection information from the sensor. [Prior art documents] [Patent documents]

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

[0004] However, the prosthetic leg described in Patent Document 1 could generate resistance to flexion and extension, but could not generate power for flexion and extension. In particular, in order to climb stairs smoothly, it was necessary to extend the knee joint while a load was applied.

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

[0006] The present invention provides A first member; A second member; a connecting portion that connects the first member and the second member so as to change an angle formed between the first member and the second member; A joint device including an expansion and contraction device that can expand and contract the angle formed between the first member and the second member, The telescopic device is A power source and a power transmission unit that transmits power from the power source, The power transmission unit is a first power transmission path that transmits the power at a first speed ratio; and a second power transmission path that transmits the power at a second speed ratio different from the first speed ratio. [Effects of the Invention]

[0007] According to the present invention, the articulating portion can be extended and bent via the power transmission portion that transmits the power of the power source. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of an electric prosthetic leg according to a first embodiment of the present invention, viewed obliquely from the front. FIG. [Figure 2] FIG. 2 is a diagram showing a power transmission unit of the electric prosthetic leg of FIG. 1. [Figure 3] 3 is a diagram showing a first speed change state in the power transmission section of FIG. 2, in which a first interrupting portion of a first interrupting mechanism is in a forced free state and a third interrupting portion of a second interrupting mechanism is in a power transmittable state. [Figure 4] 3 is a diagram showing a second speed change state in the power transmission section of FIG. 2, in which the first interrupting portion of the first interrupting mechanism is in a power transmittable state and the third interrupting portion of the second interrupting mechanism is in a forced free state. [Figure 5] 4 is a cross-sectional view taken along the line AA in FIG. 3. [Figure 6] BB cross-sectional view of FIG. 3. [Figure 7] FIG. 4 is a perspective view of the CC cross section of FIG. 3. [Figure 8] FIG. 4 is a perspective view of the cross section DD of FIG. 3. [Figure 9] 10A to 10F are diagrams illustrating the movements of a human and an electric prosthetic leg when ascending steps. [Figure 10] 9A to 9B are diagrams illustrating the power when the knee joint mechanism is extended from a bent state during ascension (FIG. 9A to FIG. 9B). [Figure 11] 9A to 9E are diagrams illustrating the power generated when the knee joint mechanism is bent from an extended state during ascent (FIG. 9D to FIG. 9E). [Figure 12] 1A and 1B are diagrams illustrating the movements of a human and an electric prosthetic leg when ascending stairs, walking on level ground, and descending stairs. [Figure 13] 10A and 10B are diagrams illustrating the power required when the knee joint mechanism is bent from an extended state while attenuating an external force when descending stairs or walking on level ground. [Figure 14] FIG. 10 is a diagram showing a modified example of an electric prosthetic leg, illustrating the power required when the knee joint mechanism is extended from a bent state while attenuating an external force during walking on flat ground. [Figure 15] FIG. 10 is a diagram showing a power transmission section of an electric prosthetic leg according to a second embodiment of the present invention. [Figure 16] FIG. 10 is a diagram showing a power transmission section of an electric prosthetic leg according to a third embodiment of the present invention. [Figure 17] FIG. 2 is a cross-sectional view of a two-way clutch. [Figure 18] FIG. 18 is a perspective view showing an example of the retainer (including rollers, guides, and rubber balls) shown in FIG. [Figure 19] 18 is a perspective view showing another example of the retainer (including rollers, guides, and O-rings) shown in FIG. 17. FIG. [Figure 20] 17A and 17B are diagrams showing the operation of the second operating mechanism 240 at the second and fourth intermittent parts shown in FIG. 16, in which (A) is a diagram showing the state in which the second intermittent part and the fourth intermittent part are off, (B) is a diagram showing the state in which the second intermittent part is on and the fourth intermittent part is off, and (C) is a diagram showing the state in which the second intermittent part is off and the fourth intermittent part is on. [Figure 21] 16A is a cross-sectional view taken along line AA in FIG. 16A showing the state in which the second interrupter is in the OFF state, and FIG. 16B is a diagram showing the position of the second operating rod 241 at that time. [Figure 22]16A is a cross-sectional view taken along the line AA in FIG. 16A, showing a state in which the second connecting / disconnecting part is turned on from off, and FIG. 16B is a view showing the position of the second operating rod 241 at that time. [Figure 23] 16, showing the second intermittent part in the forward rotation on state, and FIG. 16(B) is a diagram showing the position of the second operating rod 241 at that time. [Figure 24] 16, showing the reverse rotation on state of the second intermittent part shown in FIG. 16, and FIG. 16(B) shows the position of the second operating rod 241 at that time. [Figure 25] 16, showing the second intermittent part in the forward rotation on state, and FIG. 16(B) is a diagram showing the position of the second operating rod 241 at that time. [Figure 26] 16, showing the state in which the second interlocking unit shown in FIG. 16 has been operated from on to off, and FIG. 16(B) shows the position of the second operating rod 241 at that time. [Figure 27] FIG. 10 is a perspective view of an electric prosthetic leg according to a fourth embodiment of the present invention, as viewed obliquely from the front. [Figure 28] FIG. 28 is an exploded perspective view of the electric prosthetic leg of FIG. 27. [Figure 29] FIG. 28 is a cross-sectional view of the electric prosthetic leg of FIG. 27. [Figure 30] FIG. 28 is a cross-sectional view of the main part showing the extended state of the electric prosthetic leg of FIG. 27. [Figure 31] FIG. 28 is a cross-sectional view of the main part showing the electric prosthetic leg of FIG. 27 during bending. [Figure 32] FIG. 28 is a cross-sectional view of a main part showing the maximum bending state of the electric prosthetic leg of FIG. 27. DETAILED DESCRIPTION OF THE INVENTION

[0009] An electric prosthetic leg as one embodiment of the joint device of the present invention will be described below with reference to the drawings. In the following description, the front-to-back direction, left-to-right direction, and up-to-down direction will be defined based on the user of the electric prosthetic leg. In the drawings, the front of the electric prosthetic leg is indicated as Fr, the rear as Rr, the left side as L, the right side as R, the top as U, and the bottom as D.

[0010] [Electric prosthetic limb] As shown in Figures 1 and 2, the electric prosthetic leg 1 of the first embodiment is a prosthetic leg that is attached to the leg of a person without knees, and comprises a below-knee member 110 located below the knee, an above-knee member 120 attached to the thigh and located above the knee, a knee joint mechanism 130 that connects the below-knee member 110 and the above-knee member 120 so that the angle between them can be changed, an extension device 140 that can extend and retract to change the angle between the below-knee member 110 and the above-knee member 120, and a battery (not shown).

[0011] The above-knee component 120 has an upper wall portion 122 provided with an adapter 121 that connects to a socket (not shown), and a pair of upper side walls 123 that extend downward from both the left and right ends of the upper wall portion 122, and has an approximately U-shape that opens downward when viewed from the front-to-back direction.

[0012] The knee below-side component 110 comprises a lower wall portion 112 on which the leg portion 111 is provided, and a pair of lower side wall portions 113 extending upward from both the left and right ends of the lower wall portion 112, and has a roughly U-shape that opens upward when viewed from the front-to-back direction.

[0013] A pair of lower side walls 113 of the knee below member 110 are connected between a pair of upper side walls 123 of the knee above member 120 so as to be rotatable around the rotating parts 135. This mechanism allows the angle formed between the knee below member 110 and the knee above member 120 to be changed, thereby forming the knee joint mechanism 130.

[0014] In the space formed between the upper-knee member 120 and the lower-knee member 110, an extension device 140 is provided that can change the angle formed between the lower-knee member 110 and the upper-knee member 120.

[0015] The extension device 140 includes a motor M that outputs rotational power, a transmission T that transmits the power of the motor M, a spindle unit SP that is connected to the transmission T so that power can be transmitted and that converts the rotational power output from the transmission T into translational motion, a first interrupting mechanism 210 and a second interrupting mechanism 220 that are provided in the transmission T, a first operating mechanism 230 and a second operating mechanism 240 that switch between the first interrupting mechanism 210 and the second interrupting mechanism 220, and a rotary damper 250 that attenuates the external force input from the spindle unit SP.

[0016] The transmission T is equipped with a transmission case 160 that has a rectangular shape when viewed from the front-to-rear direction and includes a top plate 161, a bottom plate 162, a middle plate 163 that is arranged parallel to the top plate 161 and the bottom plate 162, and a pair of side plates 164 that connect the left and right ends of the top plate 161, the bottom plate 162, and the middle plate 163. The transmission case 160 is supported by the knee below member 110 via a lower swing part (not shown) so as to be swingable but immovable.

[0017] The motor M is disposed in front of and above the top plate portion 161 of the transmission case 160 so that the output shaft 171 passes through the top plate portion 161 and protrudes into the interior of the transmission case 160. The spindle unit SP is disposed on the opposite side of the motor M in the front-to-rear direction. The spindle unit SP has a spindle 173 having a male thread and a sleeve 174 having a female thread, and the sleeve 174 moves in translation along the axis of the spindle 173 as the spindle 173 rotates.

[0018] In this embodiment, the spindle 173 rotates upon receiving the rotational power of the motor M transmitted by the transmission T. Meanwhile, the sleeve 174 is immovably attached to a pair of inner side walls 124 extending downward from the upper wall 122 of the above-knee member 120, with a base 174a of the sleeve 174 swingable about the upper swing portion 125. Therefore, when the spindle 173 rotates in one direction upon receiving the rotational power of the motor M transmitted by the transmission T, the sleeve 174 translates away from the transmission T, and when the spindle 173 rotates in the other direction, the sleeve 174 translates toward the transmission T. The translational movement of the sleeve 174 away from the transmission T is sometimes referred to as an extension operation of the spindle unit SP, and conversely, the translational movement of the sleeve 174 toward the transmission T is sometimes referred to as a contraction operation of the spindle unit SP.

[0019] That is, the distance between the sleeve 174 and the transmission T expands or contracts depending on the rotation direction of the spindle 173. Because the sleeve 174 is immovably attached to the upper-knee member 120 as described above, the distance between the sleeve 174 and the transmission T expands or contracts depending on the rotation direction of the spindle 173, causing the lower-knee member 110, to which the transmission T is attached, and the upper-knee member 120, to which the sleeve 174 is attached, to rotate about the rotating part 135. This changes the angle between the upper-knee member 120 and the lower-knee member 110. If the angle between the upper-knee member 120 and the lower-knee member 110 is defined as the acute angle between acute and obtuse angles, the knee joint mechanism 130 extends as the angle increases, and the knee joint mechanism 130 flexes as the angle decreases.

[0020] 2 to 6, the transmission T includes a first transmission mechanism T1 that transmits the power of the motor M to the spindle unit SP at a first speed ratio, and a second transmission mechanism T2 that transmits the power of the motor M to the spindle unit SP at a second speed ratio different from the first speed ratio. The first transmission mechanism T1 is switched between a power disconnection state and a power connection state by a first interruption mechanism 210, and the second transmission mechanism T2 is switched between a power disconnection state and a power connection state by a second interruption mechanism 220.

[0021] Such a transmission T, by providing two power transmission paths with different gear ratios, makes it possible to switch the movement speed and generated power of extension and flexion in the knee joint mechanism 130. The first gear ratio and the second gear ratio need only be different, and either the first gear mechanism T1 or the second gear mechanism T2 may be a speed-reduction mechanism and the other an accelerating mechanism, or one may be a constant speed mechanism and the other a speed-reduction mechanism or an accelerating mechanism, or both may be speed-reduction mechanisms, or both may be accelerating mechanisms.

[0022] The first speed change ratio is the ratio of the post-speed change rotation speed, which is the rotation speed on the side opposite to the motor M (spindle unit SP side) of the first speed change mechanism T1, to the pre-speed change rotation speed, which is the rotation speed on the motor M side of the first speed change mechanism T1. The second speed change ratio is the ratio of the post-speed change rotation speed, which is the rotation speed on the side opposite to the motor M (spindle unit SP side) of the second speed change mechanism T2, to the pre-speed change rotation speed, which is the rotation speed on the motor M side of the second speed change mechanism T2.

[0023] For example, when the first speed change ratio of the first transmission mechanism T1 is smaller than 1, the rotation speed on the side opposite to the motor M (the spindle unit SP side) decreases compared to the rotation speed on the motor M side, and torque increases. When the second speed change ratio of the second transmission mechanism T2 is larger than 1, the rotation speed on the side opposite to the motor M (the spindle unit SP side) increases compared to the rotation speed on the motor M side, and torque decreases. In this embodiment, the first speed change ratio is set smaller than 1 and the second speed change ratio is set larger than 1, and the first drive gear 183 has a smaller diameter than the second drive gear 185. Note that in this embodiment, the first transmission mechanism T1 is disposed above the second transmission mechanism T2.

[0024] The first transmission mechanism T1 and the second transmission mechanism T2 include a first shaft 181 rotatably disposed on a downward extension of the output shaft 171 of the motor M, and a second shaft 182 rotatably disposed on a downward extension of the spindle 173 of the spindle unit SP. The first shaft 181 is connected to the output shaft 171 of the motor M via a coupling 187 that allows for axial center error so as to be rotatable together with the output shaft 171, and the second shaft 182 is connected to the spindle 173 of the spindle unit SP via a key 188 and key grooves 182a and 173a so as to be rotatable together with the spindle 173. The output shaft 171 of the motor M and the first shaft 181 may be connected by key fitting or spline fitting without using the coupling 187. The spindle 173 of the spindle unit SP and the second shaft 182 may be connected by spline fitting or a coupling instead of key fitting.

[0025] The first speed change mechanism T1 includes a first drive gear 183 and a first driven gear 184 that mesh with each other. The first drive gear 183 is supported by the first shaft 181 so as to be relatively rotatable, and the first driven gear 184 is supported by the second shaft 182 so as to be relatively rotatable. The first speed change mechanism T1 of this embodiment is a reduction transmission mechanism in which the first drive gear 183 has a smaller diameter than the first driven gear 184, and is capable of extending and retracting the spindle unit SP at low speed and with high torque.

[0026] The second speed change mechanism T2 includes a second drive gear 185 and a second driven gear 186 that mesh with each other. The second drive gear 185 is supported by the first shaft 181 so as to be rotatable relative to the first shaft 181, and the second driven gear 186 is supported by the second shaft 182 so as to be rotatable relative to the second shaft 182. The second speed change mechanism T2 of this embodiment is a speed-increasing transmission mechanism in which the second drive gear 185 has a larger diameter than the second driven gear 186, and is able to extend and retract the spindle unit SP at high speed and with low torque.

[0027] The first interrupting mechanism 210 includes a first interrupting part 211 provided between the first drive gear 183 and the first shaft 181, and a second interrupting part 212 provided between the first driven gear 184 and the second shaft 182.

[0028] The second interrupting mechanism 220 includes a third interrupting part 221 provided between the second drive gear 185 and the first shaft 181, and a fourth interrupting part 222 provided between the second driven gear 186 and the second shaft 182.

[0029] These interrupting portions 211, 212, 221, 222 have a common configuration and are configured to be switchable between a cut-off state in which power transmission is cut off and a power transmittable state in which rotational power can be transmitted in both one direction and the other direction.

[0030] 5 to 8, each of the intermittent units 211, 212, 221, and 222 of this embodiment is configured by combining two one-way clutches 270 with a forced free function. Each one-way clutch 270 is disposed between the outer circumferential surface of the shafts 181 and 182 and the inner circumferential surface of the gears 183 to 186, and includes a plurality of rollers 271 that are engaged when rotational power in one direction is input from the shaft side or the gear side to transmit the rotational power, and that are disengaged when rotational power in the other direction is input from the shaft side or the gear side to block the rotational power, a retainer 274 that holds the plurality of rollers 271 at a predetermined interval, and a plurality of pins 272 that forcibly hold the plurality of rollers 271 in a disengaged position to block the rotational power in one direction and the other direction. In the drawings, reference numeral 273 denotes a fixing pin that fixes the retainer 274 to the shafts 181 and 182, and reference numeral 275 denotes a spring that urges the roller 271 from the retainer 274 side toward the pin 272 side. Each of the interrupting units 211, 212, 221, and 222 is configured by stacking two one-way clutches 270 so that the rotation directions they transmit are opposite. Such interrupting units 211, 212, 221, and 222 can be switched between a cut-off state in which the two one-way clutches 270 are forcibly released to cut off power transmission, and a power transmittable state in which one of the two one-way clutches 270 is engaged and can transmit rotational power in both one and the other directions.

[0031] The first operating mechanism 230 includes a first operating rod 231 that is provided to be able to operate the pin 272 of the first interrupting unit 211 of the first interrupting mechanism 210 and the pin 272 of the third interrupting unit 221 of the second interrupting mechanism 220, and a first servo motor 232 that linearly moves the first operating rod 231. Note that the operating rod that is provided to be able to operate the pin 272 of the first interrupting unit 211 and the operating rod that is provided to be able to operate the pin 272 of the third interrupting unit 221 may be different, and a servo motor that linearly moves each operating rod may be provided.

[0032] The second operating mechanism 240 includes a second operating rod 241 that is provided to be able to operate the pin 272 of the second interrupter 212 of the first interrupter mechanism 210 and the pin 272 of the fourth interrupter 222 of the second interrupter mechanism 220, and a second servo motor 242 that linearly moves the second operating rod 241. Note that the operating rod that is provided to be able to operate the pin 272 of the second interrupter 212 and the operating rod that is provided to be able to operate the pin 272 of the fourth interrupter 222 may be different, and a servo motor that linearly moves each operating rod may be provided.

[0033] The first shaft 181 is a hollow shaft having a first internal space S1 extending in the direction of the rotation axis, and the second shaft 182 is a hollow shaft having a second internal space S2 extending in the direction of the rotation axis. The first operating rod 231 is arranged so as to be able to move up and down in the first internal space S1, and the second operating rod 241 is arranged so as to be able to move up and down in the second internal space S2. The first shaft 181 and the second shaft 182 are arranged so as to extend in the vertical direction when the user of the electric prosthetic leg 1 is standing upright.

[0034] The first operating rod 231 has a rack 231a on its lower end. A pinion 233 provided on an output shaft 232a of a first servo motor 232 meshes with the rack 231a, and the position of the first operating rod 231 is switched between an upper position shown in FIG. 3 and a lower position shown in FIG. 4 in response to driving of the first servo motor 232. Although FIGS. 3 to 6 show the first operating mechanism 230, the second operating mechanism 240 also has a similar configuration. The reference numerals in parentheses in FIGS. 3 to 8 indicate the components of the second operating mechanism 240 that correspond to the components of the first operating mechanism 230.

[0035] The second operating rod 241 has a rack 241a on the lower end side. A pinion 243 provided on an output shaft 242a of a second servo motor 242 meshes with the rack 241a, and the position of the second operating rod 241 is switched between an upper position and a lower position in response to the driving of the second servo motor 242.

[0036] The pin 272 of each of the discontinuous portions 211, 212, 221, and 222 is provided so as to be movable radially relative to the rotation axis of the first shaft 181 and the second shaft 182, and the first operating rod 231 and the second operating rod 241 are provided so that their outer peripheries abut against the inner ends of the pins 272. The outer peripheries of the first operating rod 231 and the second operating rod 241 have small diameter portions 231b and 241b that position the pins 272 in the inward forced free release position and large diameter portions 231c and 241c that push the pins 272 outward to the outward forced free position. Incidentally, an inclined portion is provided between the small diameter portions 231b and 241b and the large diameter portions 231c and 241c, connecting the small diameter portions 231b and 241b and the large diameter portions 231c and 241c without a step.

[0037] In this embodiment, a first speed change state in which the first operating rod 231 and the second operating rod 241 are positioned at an upper position, and a second speed change state in which the first operating rod 231 and the second operating rod 241 are positioned at a lower position are produced. In the first speed change state, as shown in Figures 3 and 5 to 8, the large diameter portions 231c, 241c of the first operating rod 231 and the second operating rod 241 forcibly set the first interrupting portion 211 and the second interrupting portion 212 of the first interrupting mechanism 210 free, thereby establishing a power transmission state between the motor M and the spindle unit SP via the second speed change mechanism T2. In the second speed change state, as shown in FIG. 4, the large diameter portions 231c, 241c of the first operating rod 231 and the second operating rod 241 forcibly set the third connecting / disconnecting portion 221 and the fourth connecting / disconnecting portion 222 of the second connecting / disconnecting mechanism 220 free, so that the motor M and the spindle unit SP are in a power transmission state via the first speed change mechanism T1.

[0038] An external force in the bending direction input from the spindle unit SP is transmitted to the rotary damper 250 via the first transmission mechanism T1. Specifically, an input gear 252 that meshes with the first drive gear 183 of the first transmission mechanism T1 is provided on the input shaft 251 of the rotary damper 250. In addition, a one-way clutch 253 that transmits rotation in one direction of the first transmission mechanism T1 to the rotary damper 250 and blocks rotation in the opposite direction is provided between the input shaft 251 and the input gear 252. As a result, even in the first transmission state, power transmission to the rotary damper 250 is blocked when the motor M is powered, and when the motor M is not powered (during zero torque control or regenerative control), the external force input from the spindle unit SP can be transmitted to the rotary damper 250 and attenuated.

[0039] With the electric prosthetic leg 1 configured in this way, it is possible to smoothly ascend stairs, whereas with conventional passive prosthetic legs equipped with passive dampers, it was necessary to ascend one step at a time with the non-prosthetic leg.

[0040] Specifically, as shown in (A) → (B) of Figure 9, when the electric prosthetic leg 1 is extended forward to climb stairs (ascend), a large amount of power is required to extend the knee joint mechanism 130 from a bent position when a load is applied to the electric prosthetic leg 1.

[0041] At this time, the transmission T is in a second gear state in which the first operating rod 231 and the second operating rod 241 are positioned in the lower position. In the second gear state, the large diameter portions 231c, 241c of the first operating rod 231 and the second operating rod 241 forcibly set the third connecting / disconnecting portion 221 and the fourth connecting / disconnecting portion 222 of the second connecting / disconnecting mechanism 220 free, thereby establishing a power transmission state between the motor M and the spindle unit SP via the first gear change mechanism T1.

[0042] In this state, when the motor M is rotated in a first direction (direction D1 in FIG. 10), the power of the motor M is transmitted to the first shaft 181, the first interrupting unit 211 of the first interrupting mechanism 210, the first drive gear 183, the first driven gear 184, the second interrupting unit 212 of the first interrupting mechanism 210, the second shaft 182, and the spindle unit SP. This causes the sleeve 174 to translate (extend) away from the transmission T, and the above-knee member 120 to which the sleeve 174 is attached rotates about the rotating member 135 relative to the below-knee member 110 to which the transmission T is attached, thereby extending the knee joint mechanism 130. Furthermore, since this extension power is a power that is increased in torque when it is slowed down by the first transmission mechanism T1, it is possible to reliably extend the knee joint mechanism 130 from a bent position even when a large load is placed on the electric prosthetic leg 1 when the electric prosthetic leg 1 is moved forward to climb stairs.

[0043] On the other hand, in order to smoothly ascend stairs, it is necessary to bend (lift) the knee joint mechanism 130 from an extended state while a weight is being applied to the healthy foot, as shown in (D)→(E) of Figure 9. When bending the knee joint mechanism 130 from an extended state, a large amount of power is not required, but a quick movement is required.

[0044] At this time, the transmission T is in a first speed change state in which the first operating rod 231 and the second operating rod 241 are positioned in the upper position. In the first speed change state, the large diameter portions 231c, 241c of the first operating rod 231 and the second operating rod 241 forcibly set the first interrupting portion 211 and the second interrupting portion 212 of the first interrupting mechanism 210 free, thereby establishing a power transmission state between the motor M and the spindle unit SP via the second speed change mechanism T2.

[0045] In this state, when the motor M is rotated in the second direction (direction D2 in FIG. 11 ), the power of the motor M is transmitted to the first shaft 181, the third interrupter 221 of the second interrupter mechanism 220, the second drive gear 185, the second driven gear 186, the fourth interrupter 222 of the second interrupter mechanism 220, the second shaft 182, and the spindle unit SP. This causes the sleeve 174 to translate (retract) closer to the transmission T, and the knee below-side member 110, to which the transmission T is attached, rotates about the rotating part 135 relative to the knee above-side member 120, to which the sleeve 174 is attached, thereby bending the knee joint mechanism 130. This bending power is reduced in torque when accelerated by the second transmission mechanism T2, enabling the knee joint mechanism 130 to bend quickly.

[0046] Furthermore, when descending stairs (step-down) as shown in FIG. 12 or walking on level ground, the external force in the bending direction input from the spindle unit SP is damped by the rotary damper 250, as shown in FIG. 13, thereby enabling smooth bending of the knee joint mechanism 130.

[0047] At this time, the transmission T is in a second gear state in which the first operating rod 231 and the second operating rod 241 are positioned in the lower position. In the second gear state, the large diameter portions 231c, 241c of the first operating rod 231 and the second operating rod 241 forcibly set the third connecting / disconnecting portion 221 and the fourth connecting / disconnecting portion 222 of the second connecting / disconnecting mechanism 220 free, thereby establishing a power transmission state between the motor M and the spindle unit SP via the first gear change mechanism T1.

[0048] In this state, when the motor M is subjected to zero torque control, the external force in the bending direction input from the spindle unit SP is transmitted to the second shaft 182, the second interrupter 212 of the first interrupter mechanism 210, the first driven gear 184, the first drive gear 183, the input gear 252, the one-way clutch 253, and the rotary damper 250. As a result, the external force in the bending direction input from the spindle unit SP is damped by the rotary damper 250, enabling smooth bending of the knee joint mechanism 130. Note that the motor M may be subjected to regenerative control instead of zero torque control. In this way, damping performance during bending can be improved.

[0049] Next, a modified example of the electric prosthetic leg 1 of the first embodiment will be described with reference to Fig. 14. However, for configurations common to the above embodiment, the same reference numerals as in the above embodiment will be used, and the description of the above embodiment may be used.

[0050] As shown in FIG. 14, the electric prosthetic leg 1 of the modified example differs from the above embodiment in that it is provided with a second rotary damper 260 that attenuates the external force in the extension direction input from the spindle unit SP when walking on flat ground.

[0051] An external force in the extension direction input from the spindle unit SP is transmitted to the second rotary damper 260 via the second transmission mechanism T2. Specifically, an input gear 262 that meshes with the second drive gear 185 of the second transmission mechanism T2 is provided on the input shaft 261 of the second rotary damper 260. In addition, a one-way clutch 263 that transmits rotation in one direction of the second transmission mechanism T2 to the second rotary damper 260 and blocks rotation in the opposite direction is provided between the input shaft 261 and the input gear 262. As a result, even in the first speed change state, power transmission to the second rotary damper 260 is blocked when the motor M is powered, and an external force in the extension direction input from the spindle unit SP can be transmitted to the second rotary damper 260 and attenuated when the motor M is not powered (during zero torque control or regenerative control).

[0052] More specifically, when the external force in the extension direction input from the spindle unit SP is to be damped by the second rotary damper 260, the transmission T is in a first speed change state in which the first operating rod 231 and the second operating rod 241 are positioned in the upper position. In the first speed change state, the large diameter portions 231c, 241c of the first operating rod 231 and the second operating rod 241 forcibly set the first connecting / disconnecting portion 211 and the second connecting / disconnecting portion 212 of the first connecting / disconnecting mechanism 210 free, so that the motor M and the spindle unit SP are in a power transmission state via the second speed change mechanism T2.

[0053] In this state, when the motor M is subjected to zero torque control, the external force in the extension direction input from the spindle unit SP is transmitted to the second shaft 182, the fourth interrupter 222 of the second interrupter mechanism 220, the second driven gear 186, the second drive gear 185, the input gear 262, the one-way clutch 263, and the second rotary damper 260. As a result, the external force in the extension direction input from the spindle unit SP is damped by the second rotary damper 260, allowing the knee joint mechanism 130 to move smoothly forward. Note that the motor M may be subjected to regenerative control instead of zero torque control. In this way, damping performance during extension can be improved.

[0054] Next, electric prosthetic legs 1 according to second and third embodiments of the present invention will be described with reference to Figures 15 to 26. However, for configurations common to the first embodiment, the description of the first embodiment may be cited by omitting the description or using the same reference numerals as in the first embodiment.

[0055] The transmission T of the first embodiment described above includes four two-way clutches (connecting / disconnecting units 211, 212, 221, 222) configured by combining two one-way clutches 270 each having a forced free function, and these two-way clutches are switched on and off by two actuators (servo motors 232, 242). In contrast, the transmissions T of the second and third embodiments include two two-way clutches each having a forced free function, and these two-way clutches are switched on and off by a single actuator. According to the second and third embodiments, the number of parts of the transmission T can be reduced, resulting in a simplified structure and reduced costs. The configuration of the transmissions T of the second and third embodiments, and the configuration and operation of the two-way clutches of the second and third embodiments will be described below.

[0056] 15, the transmission T of the second embodiment, like the transmission T of the first embodiment, includes a first transmission mechanism T1 that transmits the power of the motor M to the spindle unit SP at a first speed ratio, and a second transmission mechanism T2 that transmits the power of the motor M to the spindle unit SP at a second speed ratio different from the first speed ratio. The first transmission mechanism T1 is switched between a power disconnection state and a power connection state by a first interruption mechanism 210, and the second transmission mechanism T2 is switched between a power disconnection state and a power connection state by a second interruption mechanism 220.

[0057] The first transmission mechanism T1 of the second embodiment includes a first shaft 181 mechanically connected to the output shaft 171 of the motor M, a second shaft 182 mechanically connected to the spindle 173 of the spindle unit SP, a first drive gear 183 rotatably mounted on the first shaft 181, and a first driven gear 184 rotatably mounted on the second shaft 182 and rotating synchronously with the first drive gear 183.

[0058] The second transmission mechanism T2 of the second embodiment includes a first shaft 181, a second shaft 182, a second drive gear 185 that is rotatable relative to the first shaft 181, and a second driven gear 186 that is rotatable integrally with the second shaft 182 and rotates synchronously with the second drive gear 185.

[0059] The first interrupting mechanism 210 of the second embodiment includes a first interrupting part 211 provided between the first drive gear 183 and the first shaft 181, and the second interrupting mechanism 220 includes a third interrupting part 221 provided between the second drive gear 185 and the first shaft 181. That is, in the transmission T of the second embodiment, the interrupting parts 211 and 221 are provided between the first shaft 181 and each of the gears 183 and 185, and the interrupting parts 212 and 222 are not provided between the second shaft 182 and each of the gears 184 and 186.

[0060] These interrupting units 211 and 221 have a common configuration and are configured to be switchable between a cut-off state in which power transmission is cut off and a power transmittable state in which rotational power can be transmitted in both one direction and the other direction.

[0061] As shown in FIG. 16, the transmission T of the third embodiment includes a first transmission mechanism T1, a second transmission mechanism T, a first interrupter mechanism 210, and a second interrupter mechanism 220, similar to the transmission T of the second embodiment.

[0062] The first transmission mechanism T1 of the third embodiment includes a first shaft 181, a second shaft 182, a first drive gear 183 that is rotatable integrally with the first shaft 181, and a first driven gear 184 that is rotatable relative to the second shaft 182 and rotates synchronously with the first drive gear 183.

[0063] The second transmission mechanism T2 of the third embodiment includes a first shaft 181, a second shaft 182, a second drive gear 185 that is rotatable integrally with the first shaft 181, and a second driven gear 186 that is rotatable relative to the second shaft 182 and rotates synchronously with the second drive gear 185.

[0064] The first interrupting mechanism 210 of the third embodiment includes a second interrupting part 212 provided between the first driven gear 184 and the second shaft 182, and the second interrupting mechanism 220 includes a fourth interrupting part 222 provided between the second driven gear 186 and the second shaft 182. That is, in the transmission T of the third embodiment, the interrupting parts 212 and 222 are provided between the second shaft 182 and each of the gears 184 and 186, and the interrupting parts 211 and 221 are not provided between the first shaft 181 and each of the gears 183 and 185.

[0065] These interrupting portions 212, 222 have a common configuration and are configured to be switchable between a cut-off state in which power transmission is cut off and a power transmittable state in which rotational power can be transmitted in both one direction and the other direction.

[0066] Each of the interrupting portions 211, 221 of the second embodiment and each of the interrupting portions 212, 222 of the third embodiment are configured using a two-way clutch 280 with a forced free function, as shown in Fig. 17. The two-way clutch 280 includes a plurality of rollers 281 (three in this embodiment) arranged between the outer circumferential surfaces of the shafts 181, 182 and the inner circumferential surfaces of the gears 183 to 186, a retainer 282 that holds the plurality of rollers 281 at predetermined intervals, a plurality of pins 283 (three in this embodiment) that radially penetrate the shafts 181, 182 and are operated between a forced free position and a forced free release position by the first operating mechanism 230 or the second operating mechanism 240, and a plurality of guides 284 (three in this embodiment) that are provided on the retainer 282 and that determine the relative rotation position of the retainer 282 with respect to the shafts 181, 182 when the pins 283 are in the forced free position.

[0067] A radial distance A (not shown) between the outer peripheral surfaces of shafts 181 and 182 and the inner peripheral surfaces of gears 183 to 186 is smaller than a diameter B (not shown) of roller 281. Furthermore, flat portions 281a and 282a are formed at predetermined intervals in the circumferential direction on the outer peripheral portions of shafts 181 and 182, and the distance A is larger than the diameter B at the circumferential center side of flat portions 281a and 282a.

[0068] In other words, when roller 281 is held in the circumferential center of flat portions 281a, 282a, roller 281 does not mesh with the outer peripheral surfaces of shafts 181, 182 and the inner peripheral surfaces of gears 183-186, and relative rotation between shafts 181, 182 and gears 183-186 is permitted (forced free state).

[0069] On the other hand, when roller 281 is allowed to move circumferentially relative to shafts 181 and 182, roller 281 meshes with the outer peripheral surfaces of shafts 181 and 182 and the inner peripheral surfaces of gears 183 to 186, and shafts 181 and 182 and gears 183 to 186 are connected so that they can rotate together in two directions (forced free release state).

[0070] As shown in FIG. 18, retainer 282 is ring-shaped and rotatable relative to shafts 181, 182 and gears 183 to 186, and has a plurality of roller holding portions 282a that hold rollers 281 and a plurality of guide holding portions 282b that hold guides 284.

[0071] Additionally, a plurality of rubber balls 282c are embedded at predetermined intervals in the circumferential direction on the outer peripheral surface of retainer 282. These rubber balls 282c prevent unintended spinning in the forced free release state by generating appropriate friction between gears 183-186 and retainer 282. Note that the member that generates friction between gears 183-186 and retainer 282 may be an O-ring 282d as shown in FIG. 19. Additionally, although rubber balls 282c and O-ring 282d are effective in preventing spinning, they may be omitted.

[0072] 17, pin 283 has a conical protrusion 283a on its radially outer end, and guide 284 has a conical recess 284a on its radially inner end face that fits (engages) with protrusion 283a. When protrusion 283a of pin 283 fits into recess 284a of guide 284, the guiding action of pin 283 and guide 284 positions retainer 282 at a predetermined position where the relative rotation position with respect to shafts 181, 182 is forced free.

[0073] 15 and 16, shafts 181 and 182 are formed with, in order from top to bottom, first large diameter portions 231c1 and 241c1, first small diameter portions 231b1 and 241b1, second large diameter portions 231c2 and 241c2, second small diameter portions 231b2 and 241b2, and third large diameter portions 231c3 and 241c3 at predetermined lengths and intervals. Shafts 181 and 182 are each provided so that two interrupted portions can be controlled simultaneously, but may be provided separately for each interrupted portion.

[0074] In the following, the operation of the second operating mechanism 240 that simultaneously controls the intermittent portions 212, 222 of the third embodiment will be described with reference to FIG. As shown in FIG. 20, the interrupters 212, 222 are switched by a second operating mechanism 240 between a forced free state (hereinafter referred to as an OFF state as appropriate) and a forced free release state (hereinafter referred to as an ON state as appropriate).

[0075] When the second operating rod 241 of the second operating mechanism 240 is in the upper position shown in (A) of Figure 20, the second large diameter portion 241c2 pushes the pin 283 of the second interrupting portion 212 in the outer diameter direction, while the third large diameter portion 241c3 pushes the pin 283 of the fourth interrupting portion 222 in the outer diameter direction, thereby turning the second interrupting portion 212 and the fourth interrupting portion 222 to the off state.

[0076] Furthermore, when the second operating rod 241 of the second operating mechanism 240 is in the middle position shown in (B) of Figure 20, the first small diameter portion 241b1 allows the pin 283 of the second interrupting portion 212 to return in the inner diameter direction, while the third large diameter portion 241c3 pushes the pin 283 of the fourth interrupting portion 222 in the outer diameter direction, thereby turning the second interrupting portion 212 to the ON state and the fourth interrupting portion 222 to the OFF state.

[0077] Furthermore, when the second operating rod 241 of the second operating mechanism 240 is in the lower position shown in (C) of Figure 20, the first large diameter portion 241c1 pushes the pin 283 of the second interrupting portion 212 in the outer diameter direction, while the second small diameter portion 241b2 allows the pin 283 of the fourth interrupting portion 222 to return in the inner diameter direction, thereby putting the second interrupting portion 212 in the OFF state and the fourth interrupting portion 222 in the ON state.

[0078] Although not shown, each of the intermittent portions 211, 221 of the second embodiment is also switched between a forced free state and a forced free release state by the first operation mechanism 230. The first operation rod 231 of the first operation mechanism 230 is configured to be movable to an upper position (a position corresponding to the position (A) in FIG. 20), a middle position (a position corresponding to the position (B) in FIG. 20), and a lower position (a position corresponding to the position (C) in FIG. 20). In the upper position, the first operating rod 231 of the first operating mechanism 230 pushes the pins 283 of the first interrupting portion 211 and the third interrupting portion 221 in the outer radial direction, thereby turning the first interrupting portion 211 and the third interrupting portion 221 to the off state; in the middle position, it allows the pin 283 of the first interrupting portion 211 to return in the inner radial direction while pushing the pin 283 of the third interrupting portion 221 in the outer radial direction, thereby turning the first interrupting portion 211 to the on state and the third interrupting portion 221 to the off state; and in the lower position, it pushes the pin 283 of the first interrupting portion 211 in the outer radial direction while allowing the pin 283 of the third interrupting portion 221 to return in the inner radial direction, thereby turning the first interrupting portion 211 to the off state and the third interrupting portion 221 to the on state.

[0079] Next, the operation of the two-way clutch 280 will be described with reference to Figures 21 to 26 using the second intermittent portion 212 of the third embodiment as an example. In the following example, the transition from (A) to (C) in Figure 20 via (B) in the second intermittent portion 212 will be described as an example.

[0080] 21A and 21B, in a state in which the second large diameter portion 241c2 of the second operating rod 241 pushes the pin 283 of the second intermittent portion 212 in the outer diameter direction, the convex portion 283a of the pin 283 fits into the concave portion 284a of the guide 284, and the relative rotational position of the retainer 282 with respect to the second shaft 182 is fixed at a predetermined position. In this state, the roller 281 is held in the circumferential center portion of the flat portion 282a, and therefore the roller 281 does not mesh with the outer peripheral surface portion of the second shaft 182 and the inner peripheral surface portion of the first driven gear 184, resulting in an OFF state in which relative rotation between the second shaft 182 and the first driven gear 184 is permitted.

[0081] 22A and 22B show a state in which the second operating rod 241 has moved from a position where the second large diameter portion 241c2 pushes the pin 283 of the second intermittent portion 212 in the outer diameter direction to a position where the first small diameter portion 241b1 allows the pin 283 to return in the inner diameter direction. In Fig. 22, the pin 283 has already moved in the inner diameter direction, but in reality, at the timing when relative rotation occurs between the second shaft 182 and the first driven gear 184, the guide 284 of the retainer 282, which rotates together with the first driven gear 184, pushes the pin 283 back in the inner diameter direction with the inclined surface of the recess 284a.

[0082] 23A and 23B, when relative rotation in the forward direction indicated by the arrow in the figure occurs between second shaft 182 and first driven gear 184 while pin 283 is allowed to return in the radially inward direction, retainer 282, which rotates together with first driven gear 184, moves roller 281 in the forward direction relative to second shaft 182. As a result, roller 281 meshes with the outer peripheral surface of second shaft 182 and the inner peripheral surface of first driven gear 184, creating a forward rotation on state in which second shaft 182 and first driven gear 184 rotate integrally in the forward direction.

[0083] 24A and 24B, when relative rotation in the reverse direction indicated by the arrow in the figure occurs between second shaft 182 and first driven gear 184 while pin 283 is allowed to return in the radially inward direction, retainer 282, which rotates together with first driven gear 184, moves roller 281 in the reverse direction relative to second shaft 182. As a result, roller 281 meshes with the outer peripheral surface of second shaft 182 and the inner peripheral surface of first driven gear 184, creating a reverse-on state in which second shaft 182 and first driven gear 184 rotate integrally in the reverse direction. Retainer 282 can be seen as one element of the actuator of the operating unit that moves roller 281, and can also be seen as one element of an engager that is controlled by pin 283 and guide 284 to a position that is in a forced free state and a position that is in a forced free release state.

[0084] 26A and 26B, when the second operating rod 241 moves from a position where the first small diameter portion 241b1 allows the pin 283 of the second intermittent portion 212 to return in the inner diameter direction to a position where the first large diameter portion 241c1 pushes the pin 283 outward, the convex portion 283a of the pin 283 fits into the concave portion 284a of the guide 284, and the relative rotational position of the retainer 282 with respect to the second shaft 182 is fixed in a predetermined position by the guiding action of the pin 283 and the guide 284. In this state, the roller 281 is held in the circumferential center of the flat portion 282a, and therefore the roller 281 does not mesh with the outer circumferential surface of the second shaft 182 and the inner circumferential surface of the first driven gear 184, resulting in an off state in which relative rotation between the second shaft 182 and the first driven gear 184 is permitted.

[0085] Although detailed explanation will be omitted, the bidirectional clutch 280 of the fourth interrupter 222 of the third embodiment and the first interrupter 211 and third interrupter 221 of the second embodiment operates in the same manner, and the bidirectional clutch 280 can be in an OFF state, a forward rotation ON state, and a reverse rotation ON state. According to the transmissions T of the second and third embodiments, the number of parts can be reduced compared to the transmission T of the first embodiment, as described above, thereby simplifying the structure and reducing costs. Furthermore, when the motor M is located upstream and the spindle unit SP is located downstream in the power transmission path of the motor M, the transmission T of the third embodiment is provided with the second interrupter 212 and the fourth interrupter 222 on the downstream side. Therefore, when the interrupters 212, 222 are located in the OFF state, fewer rotating bodies rotate, resulting in a more agile operation of the electric prosthetic leg 1.

[0086] Next, an electric prosthetic leg 1 according to a fourth embodiment of the present invention will be described with reference to Figures 27 to 32. However, for configurations common to the second embodiment, the same reference numerals as in the second embodiment will be used, and the description of the second embodiment may be used.

[0087] The electric prosthetic leg 1 of the fourth embodiment differs from the third embodiment mainly in the configuration of the housing, the arrangement of the spindle unit SP, the fact that the sleeve 174 of the spindle unit SP is connected to the above-knee member 120 via a link member 320, the arrangement of the first and second speed change mechanisms T1 and T2, the shapes of the drive gears 183, 185 and driven gears 184, 186, and the inclusion of an extension assist mechanism 330 that assists in the extension of the knee joint mechanism 130 with the force stored when the knee is flexed. Each of the differences will be explained in detail below.

[0088] As shown in Figures 27 and 28, the housing 310 of the electric prosthetic leg 1 of the fourth embodiment includes a box-shaped main frame 311 that is open at the top and rear and that constitutes the knee-lower member 110, side covers 312 that cover both the left and right sides of the main frame 311, and a detachable rear cover 313 that covers the rear opening of the main frame 311 in an openable and closable manner.

[0089] The upper knee member 120 is attached to the upper part of the main frame 311 via a rotating part 135, and the leg part 111 is attached to the lower part of the main frame 311. A unitized telescopic device 140 is also incorporated inside the main frame 311. The telescopic device 140 has a unit case 315 supported on the main frame 311 via a bracket 316.

[0090] 29, the transmission T includes a first transmission mechanism T1, a second transmission mechanism T, a first interrupter mechanism 210, and a second interrupter mechanism 220. The transmission T of the fourth embodiment differs from the transmission T of the second embodiment in that the first transmission mechanism T1 is disposed below the second transmission mechanism T2.

[0091] The first transmission mechanism T1 includes a first shaft 181 mechanically connected to the output shaft of the motor M, a second shaft 182 mechanically connected to the spindle 173 of the spindle unit SP, a first drive gear 183 rotatable relative to the first shaft 181, and a first driven gear 184 rotatable integrally with the second shaft 182 and rotating synchronously with the first drive gear 183.

[0092] The second transmission mechanism T2 includes a first shaft 181, a second shaft 182, a second drive gear 185 that is rotatable relative to the first shaft 181, and a second driven gear 186 that is rotatable integrally with the second shaft 182 and rotates synchronously with the second drive gear 185.

[0093] The first interrupting mechanism 210 includes a first interrupting part 211 provided between the first drive gear 183 and the first shaft 181, and the second interrupting mechanism 220 includes a third interrupting part 221 provided between the second drive gear 185 and the first shaft 181. That is, in the transmission T of the fourth embodiment, the interrupting parts 211 and 221 are provided between the first shaft 181 and each of the gears 183 and 185, and the interrupting parts 212 and 222 are not provided between the second shaft 182 and each of the gears 184 and 186. Note that, as in the second embodiment, each of the interrupting parts 211 and 221 includes a two-way clutch 280, and therefore detailed description thereof will be omitted.

[0094] As shown in Figures 29 to 32, in the electric prosthetic leg 1 of the fourth embodiment, the spindle unit SP is disposed forward of the rotating unit 135, and the knee joint mechanism 130 is bent in response to the extending operation of the spindle unit SP, and is extended in response to the retracting operation of the spindle unit SP. With this configuration, during high-torque operation ((A) to (B) in Figure 9) to extend the knee joint mechanism 130 from a bent state, a force acts on the spindle 173 of the spindle unit SP in the direction opposite to the direction of gravity, so it is possible to avoid an increase in the size of the support structure that supports the spindle 173. In other words, extending the knee joint mechanism 130 from a bent state is when the angle between the below-knee member 110 and the above-knee member 120 becomes larger.

[0095] 29, the spindle 173 is integrally connected to a second shaft 182 that is integrated with a first driven gear 184 and a second driven gear 186, and the second shaft 182 is supported by the unit case 315 via a pair of upper and lower bearings BRG. When the angle between the above-knee component 120 and the below-knee component 110 increases as the spindle unit SP contracts, a force in the direction opposite to the direction of gravity acts on the spindle 173 of the spindle unit SP, preventing the bearings BRG from becoming larger.

[0096] Furthermore, during high torque operation to extend the knee joint mechanism 130 from a bent state, the spindle 173 of the spindle unit SP receives a tensile load from the sleeve 174 side, so that buckling deformation of the spindle 173 can be prevented.

[0097] Furthermore, gears 183 to 186 are all helical gears, and when motor M is driven, a thrust force acts from drive gears 183 and 185 to driven gears 184 and 186. By configuring gears 183 to 186 so that this thrust force acts on spindle 173 in the direction opposite to the direction of gravity, it is possible to avoid an increase in the size of the support structure that supports spindle 173.

[0098] As shown in Figure 29, in the electric prosthetic leg 1 of the fourth embodiment, the sleeve 174 of the spindle unit SP is connected to the above-knee member 120 via a link member 320. Specifically, the upper end of the sleeve 174 is connected to the lower end of the link member 320 via a first rotating part 321, and the upper end of the link member 320 is connected to the above-knee member 120 via a second rotating part 322. In this way, it becomes possible to flex and extend the knee joint mechanism 130 in response to the extension and contraction of the spindle unit SP, without supporting the entire extension device 140 so that it can swing, as in the electric prosthetic legs 1 of the first to third embodiments.

[0099] FIG. 30 shows the electric prosthetic leg 1 of the fourth embodiment in an extended state, FIG. 31 shows the electric prosthetic leg 1 in an extended state, and FIG. 32 shows the electric prosthetic leg 1 in a maximum bent state. Note that the maximum bent state shown in FIG. 32 is not reached while the electric prosthetic leg 1 is walking. In FIG. 30, a first stopper 342 attached to a support piece 341 that supports the second rotating portion 322 abuts against a position regulating pin 350, preventing the knee joint mechanism 130 from bending in the opposite direction. Also, in FIG. 32, a second stopper 343 attached to the above-knee member 120 abuts against the position regulating pin 350, preventing the knee joint mechanism 130 from bending further from the maximum bent state. Note that in FIGS. 30 to 32, the symbol B denotes a battery that supplies power to the motor M.

[0100] As shown in Figures 29 to 32, an extension assist mechanism 330 is provided between the upper end of the link member 320 and the knee upper member 120, which assists extension with force stored when the knee joint mechanism 130 is bent. The extension assist mechanism 330 has a pressing portion 332 that presses the upper end of the link member 320 with the biasing force of a spring 331 (e.g., a compression coil spring). A cam portion 323 is formed at the upper end of the link member 320. The cam portion 323 continuously has a small-diameter outer periphery portion 323a centered on the second rotating portion 322, a large-diameter outer periphery portion 323b that is distant from the second rotating portion 322, and a connecting outer periphery portion 323c that seamlessly connects the small-diameter outer periphery portion 323a and the large-diameter outer periphery portion 323b.

[0101] As shown in Figure 30, when the knee joint mechanism 130 is in an extended state with the spindle unit SP contracted, the pressing portion 332 abuts against the small diameter outer periphery 323a of the cam portion 323. As shown in Figure 31, when the spindle unit SP extends from the extended state of the knee joint mechanism 130 and the knee joint mechanism 130 is bent, the abutment position between the pressing portion 332 and the cam portion 323 moves from the small diameter outer periphery 323a to the large diameter outer periphery 323b, and the pressing portion 332 is pressed against the biasing force of the spring 331, causing the spring 331 to store energy.

[0102] Conversely, when the spindle unit SP contracts from the bent state of the knee joint mechanism 130 and the knee joint mechanism 130 moves from the bent state to the extension side, the contact position between the pressing portion 332 and the cam portion 323 moves from the large diameter outer periphery portion 323b to the small diameter outer periphery portion 323a, and the stored force of the spring 331 acts in a direction to contract the spindle unit SP via the pressing portion 332 and the link member 320. This enables the extension assist mechanism 330 to assist in the extension of the knee joint mechanism 130 with the force stored when the knee joint mechanism 130 is bent.

[0103] In the transmission T of the fourth embodiment, a configuration has been exemplified in which interruptions 211, 221 are provided between the first shaft 181 and each gear 183, 185, and interruptions 212, 222 are not provided between the second shaft 182 and each gear 184, 186, but as with the transmission T of the third embodiment, a configuration may also be used in which interruptions 212, 222 are provided between the second shaft 182 and each gear 184, 186, and interruptions 211, 221 are not provided between the first shaft 181 and each gear 183, 185.

[0104] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0105] For example, in the above embodiment, a prosthetic leg device (electric prosthetic leg) applied to a knee joint was exemplified as one embodiment of the joint device of the present invention, but the present invention is not limited to this and may also be a prosthetic limb device (electric prosthetic limb) applied to an elbow joint, and the wearer may be an animal other than a human, or may be a robot. When applied to an elbow joint, the below-knee member 110 in the above embodiment is the distal side of the wearer, i.e., the forearm, relative to the above-knee member 120.

[0106] Furthermore, the telescopic device 140, the transmission T, the first interrupting mechanism 210 and the second interrupting mechanism 220 provided in the transmission T, or the first operating mechanism 230 and the second operating mechanism 240 that switch between the first interrupting mechanism 210 and the second interrupting mechanism 220, etc., in the above-described embodiment are not limited to coupling devices and may be applied to a drive device for a moving body such as a vehicle, or to a drive device for a work machine such as a snow blower or a lawn mower.

[0107] This specification also describes at least the following: Note that the components in parentheses correspond to those in the above-described embodiment, but are not limited to these.

[0108] (1) a first member (the lower-knee member 110); A second member (above-knee member 120), a joint portion (knee joint mechanism 130) that connects the first member and the second member so as to change the angle between them; A joint device (electric prosthetic leg 1) including an extension device (extension device 140) that can change the angle between the first member and the second member by extending and contracting, The telescopic device is A power source (motor M), a power transmission unit (transmission T) that transmits the power of the power source, The power transmission unit is a first power transmission path (first speed change mechanism T1) that transmits the power at a first speed change ratio; a second power transmission path (second speed change mechanism T2) that transmits the power at a second speed change ratio different from the first speed change ratio, the coupling device comprising:

[0109] According to (1), the articulating part can be extended and bent via the power transmission part that transmits the power of the power source. In addition, the power transmission part has two power transmission paths with different gear ratios, so the speed of extension and bending and the generated power of the articulating part can be switched.

[0110] (2) The coupling device according to (1), The telescopic device is a first interrupting mechanism (first interrupting mechanism 210) that switches between interruption and connection of power in the first power transmission path; a second interrupting mechanism (second interrupting mechanism 220) that switches between disconnection and connection of power in the second power transmission path.

[0111] According to (2), the device is provided with a first interrupting mechanism that switches between disconnecting and connecting power in the first power transmission path, and a second interrupting mechanism that switches between disconnecting and connecting power in the second power transmission path, so that the two power transmission paths can be appropriately switched.

[0112] (3) The coupling device according to (1) or (2), The first power transmission path includes a first rotating body (first drive gear 183) and a second rotating body (first driven gear 184) that are provided to rotate synchronously with each other, and (i) a third rotating body (first shaft 181) that is provided so as to be rotatable relative to the first rotating body, and a fourth rotating body (second shaft 182) that is provided so as to be rotatable relative to the second rotating body; or (ii) a third rotating body (first shaft 181) that is provided so as to be rotatable relative to the first rotating body, and a fourth rotating body (second shaft 182) that is provided so as to be rotatable integrally with the second rotating body; Or, (iii) a third rotating body (first shaft 181) that is provided so as to be rotatable integrally with the first rotating body, and a fourth rotating body (second shaft 182) that is provided so as to be rotatable relative to the second rotating body, The second power transmission path includes a fifth rotor (second drive gear 185) and a sixth rotor (second driven gear 186) that are provided to rotate synchronously with each other, and (i) a seventh rotating body (first shaft 181) that is provided so as to be rotatable relative to the fifth rotating body, and an eighth rotating body (second shaft 182) that is provided so as to be rotatable relative to the sixth rotating body; (ii) a seventh rotor (first shaft 181) that is rotatable relative to the fifth rotor, and an eighth rotor (second shaft 182) that is rotatable integrally with the sixth rotor; Or, (iii) A coupling device comprising a seventh rotating body (first shaft 181) that is rotatable integrally with the fifth rotating body, and an eighth rotating body (second shaft 182) that is rotatable relative to the sixth rotating body.

[0113] According to (3), the first to eighth rotors can form the first power transmission path and the second power transmission path.

[0114] (4) The coupling device according to (3), a coupling device, wherein the third rotating body and the seventh rotating body are mechanically connected to the power source;

[0115] According to (4), power from the power source is input to the first power transmission path and the second power transmission path. Note that "mechanically connected" includes various connection modes that allow power transmission, such as direct connection, fastening, or integral formation, as well as modes that allow power transmission via other members.

[0116] (5) The coupling device according to (4), The third rotating body and the seventh rotating body are provided so as to be able to rotate integrally.

[0117] According to (5), it is possible to use the same rotating body and simplify the connecting structure of the rotating body, so the telescopic device can be made compact. Note that "rotatable as a unit" may mean that the rotating body is made of the same material, or that separate members are connected so that they rotate as a unit.

[0118] (6) A coupling device according to any one of (3) to (5), The telescopic device is The power transmission unit further includes a motion conversion mechanism (spindle unit SP) that is mechanically connected to the power transmission unit and converts the rotational power output from the power transmission unit into translational motion, a coupling device, wherein the fourth rotating body and the eighth rotating body are mechanically connected to the motion conversion mechanism;

[0119] According to (6), power from the power source is output to the motion conversion mechanism via the first power transmission path and the second power transmission path.

[0120] (7) The coupling device according to (6), A coupling device, wherein the fourth rotating body and the eighth rotating body are arranged to be able to rotate integrally.

[0121] According to (7), it is possible to use the rotating body for multiple purposes and simplify the connecting structure of the rotating body, so that the telescopic device can be configured compactly.

[0122] (8) The coupling device according to (6) or (7), The first power transmission path includes the first rotating body and the second rotating body, and, (i) the third rotating body provided so as to be rotatable relative to the first rotating body, and the fourth rotating body provided so as to be rotatable relative to the second rotating body; Or, (iii) the third rotating body provided so as to be rotatable integrally with the first rotating body, and the fourth rotating body provided so as to be rotatable relative to the second rotating body; Equipped with the second power transmission path includes the fifth rotating body and the sixth rotating body, and, (i) the seventh rotor provided so as to be rotatable relative to the fifth rotor, and the eighth rotor provided so as to be rotatable relative to the sixth rotor; Or, (iii) the seventh rotor provided so as to be integrally rotatable with the fifth rotor, and the eighth rotor provided so as to be relatively rotatable with the sixth rotor; Equipped with The telescopic device is a first interrupting mechanism (first interrupting mechanism 210) that switches between interruption and connection of power in the first power transmission path; a second interrupting mechanism (second interrupting mechanism 220) that switches between interruption and connection of power in the second power transmission path, The first interrupting mechanism is (i) a first interruption portion (first interruption portion 211) provided between the first rotating body and the third rotating body and a second interruption portion (second interruption portion 212) provided between the second rotating body and the fourth rotating body; Or, (iii) a second interrupted portion (second interrupted portion 212) provided between the second rotating body and the fourth rotating body; The second interrupting mechanism is (i) a third interruption portion (third interruption portion 221) provided between the fifth rotating body and the seventh rotating body and a fourth interruption portion (fourth interruption portion 222) provided between the sixth rotating body and the eighth rotating body; Or, (iii) A coupling device including a fourth interrupting portion (fourth interrupting portion 222) provided between the sixth rotating body and the eighth rotating body.

[0123] According to (8), when the power source is located upstream and the motion conversion mechanism is located downstream, an interrupter is provided at least downstream, so that when the interrupter is turned off, the number of rotating bodies that rotate together is reduced, making the operation of the coupling device smoother.

[0124] (9) The coupling device according to (8), The second interrupting unit of the first interrupting mechanism and the fourth interrupting unit of the second interrupting mechanism are The engaging elements (rollers 271, 281, retainers 274, 282) are respectively disposed between the second rotating body and the fourth rotating body, or between the sixth rotating body and the eighth rotating body, The coupling device includes the first and second intermittent mechanisms each having an operating portion (pins 272, 283, retainers 274, 282, guide 284, second operating rod 241) that operates the engaging element between an engaged state and a disengaged state.

[0125] According to (9), the second interrupter of the first interrupter mechanism and the fourth interrupter of the second interrupter mechanism can be appropriately switched between the off state and the on state by the operating unit.

[0126] (10) The coupling device according to (9), The operation units of the first interrupting mechanism and the second interrupting mechanism are an actuator (pins 272, 283, retainers 274, 282, guide 284) for moving the engaging element; and an operating element (second operating rod 241) that is provided so as to be able to operate the actuator.

[0127] According to (10), the second interrupter of the first interrupter mechanism and the fourth interrupter of the second interrupter mechanism can be appropriately switched between the off state and the on state by the actuator and the operator.

[0128] (11) The coupling device according to (10), the fourth rotor and the eighth rotor are hollow so as to have a common internal space (second internal space S2) extending in the rotation axis direction, The operating element of the first interrupting mechanism and the operating element of the second interrupting mechanism are arranged to be located in the internal space.

[0129] According to (11), the first interrupting mechanism and the second interrupting mechanism can be configured compactly.

[0130] (12) The coupling device according to (11), the operating element of the first interrupting mechanism and the operating element of the second interrupting mechanism are integrally formed, The extension device is a joint device further comprising a drive unit (second servo motor 242) that drives the integrally formed operating element.

[0131] According to (12), only one driving unit is required, so the telescopic device can be configured compactly.

[0132] (13) A coupling device according to any one of (10) to (12), The actuators of the first interrupting mechanism and the second interrupting mechanism are The fourth rotor and the eighth rotor each have a reciprocating element (pin 272, 283) that is movable back and forth along a radial direction relative to the rotation axis of the fourth rotor and the eighth rotor, The operation elements of the first interrupting mechanism and the second interrupting mechanism are The large diameter portion 241c extends along the rotation axis and is movable back and forth along the rotation axis. The operating element is provided so that the outer periphery of the extension portion abuts against the end of the advancing / retreating element on the side of the rotation axis.

[0133] According to (13), the extension portion provided so as to be movable forward and backward along the rotation axis can move the advancing and retracting element forward and backward along the radial direction.

[0134] (14) The coupling device according to (13), The extension portion is a first extending portion (a first large diameter portion 241c1, a second large diameter portion 241c2, a third large diameter portion 241c3) that comes into contact with the advancing / retreating element of the first interrupting mechanism; a second extending portion (a first large diameter portion 241c1, a second large diameter portion 241c2, a third large diameter portion 241c3) that comes into contact with the advancing / retreating element of the second interrupting mechanism, A coupling device, wherein the first extension portion and the second extension portion are arranged to be located at different positions in the direction of the rotation axis.

[0135] According to (14), by moving the operating element back and forth along the rotation axis, the advancing and retracting element of the first interrupting mechanism and the advancing and retracting element of the second interrupting mechanism can be controlled.

[0136] (15) A coupling device according to (13) or (14), The advancing and retreating elements of the first interrupting mechanism and the second interrupting mechanism are When the engaging element is positioned on the outer side in the radial direction, the engaging element is in one of the engaged state and the disengaged state, a coupling device configured so that the engaging element is in the other of the engaged state and the disengaged state when positioned on the inner side in the radial direction.

[0137] According to (15), the engaged state and the disengaged state can be controlled according to the radial position of the advancing / retracting element.

[0138] (16) The coupling device according to (15), The operator is When the rotor is located at the first position (lower position) in the direction of the rotation axis, the advancing / retracting element of the first interrupting mechanism is located on the outer side in the radial direction, and the advancing / retracting element of the second interrupting mechanism is located on the inner side in the radial direction, When the rotor is located at the second position (middle position) in the direction of the rotation axis, a coupling device in which the advancing / retracting element of the first interrupting mechanism is located on the inner side in the radial direction, and the advancing / retracting element of the second interrupting mechanism is located on the outer side in the radial direction.

[0139] According to (16), by moving the operating element back and forth along the rotation axis to the first position or the second position, it is possible to reliably prevent the first power transmission path and the second power transmission path from being able to transmit power simultaneously.

[0140] (17) The coupling device according to (16), The advancing and retreating elements of the first interrupting mechanism and the second interrupting mechanism are When the engaging element is positioned on the outer side in the radial direction, the engaging element is in the disengaged state, The extension portion is When the rotational axis direction is in a third position (upper position) different from the first position and the second position, a coupling device in which the advancing / retracting element of the first interrupting mechanism is located on the outer side in the radial direction, and the advancing / retracting element of the second interrupting mechanism is located on the outer side in the radial direction.

[0141] According to (17), by moving the operating element to the third position along the rotation axis, power transmission can be disabled simultaneously through the first power transmission path and the second power transmission path.

[0142] (18) A coupling device according to any one of (13) to (17), The engaging elements of the first interrupting mechanism and the second interrupting mechanism are a plurality of engaging bodies (rollers 271, 281) disposed at intervals in the circumferential direction relative to the rotation axes of the fourth rotating body and the eighth rotating body; The actuators of the first interrupting mechanism and the second interrupting mechanism are A plurality of the advancing and retracting elements (pins 272, 283) that are arranged at intervals in the circumferential direction relative to the rotation axis and move the plurality of engaging bodies; a retainer (retainers 274, 282) that holds the plurality of engaging bodies and the plurality of advancing and retracting elements.

[0143] According to (18), the actuator is composed of a plurality of advancing and retreating elements and a retainer.

[0144] (19) The coupling device according to (18), The first interrupting mechanism and the second interrupting mechanism are The coupling device includes an interposition member (a rubber ball 282c, an O-ring 282d) interposed between the cage and the second rotating body or the sixth rotating body.

[0145] According to (19), it is possible to assist the second and fourth rotating bodies, or the sixth and eighth rotating bodies, in changing from a non-engaged state to an engaged state.

[0146] (20) A coupling device according to any one of (13) to (17), The engaging elements of the first interrupting mechanism and the second interrupting mechanism are a plurality of engaging bodies (rollers 271, 281) arranged at intervals in the circumferential direction relative to the rotation axes of the fourth rotating body and the eighth rotating body; and a retainer (retainers 274, 282) that holds the plurality of engaging bodies, The advancing and retreating elements of the first interrupting mechanism and the second interrupting mechanism are A coupling device adapted to move a plurality of said mating elements through said retainer.

[0147] According to (20), the engaging element is composed of a plurality of engaging bodies and a retainer.

[0148] (21) A coupling device according to any one of (1) to (20), A joint device that is a prosthetic device that is attached to a main body so that the first member is on the distal side of the main body relative to the second member.

[0149] According to (21), the joint device can be used as a prosthetic device.

[0150] (22) The coupling device according to (21), The prosthetic limb device is a joint device that is a prosthetic leg device that is attached to the leg of the wearer.

[0151] According to (22), the joint device can be used as a prosthetic device.

[0152] (23) The coupling device according to (22), the second member is attached to the thigh of the leg; A joint device wherein the articulation portion is adapted to function as a knee joint between the thigh and shank.

[0153] According to (23), the joint device can be used as a knee joint.

[0154] (24) A coupling device according to any one of (3) or (4) to (23) dependent on (3), The joint device is a prosthetic device that is attached to a main body such that the first member is located on the distal side of the main body relative to the second member, the prosthetic limb device is a prosthetic leg device attached to a leg of the wearer, A coupling device in which the first rotating body, the second rotating body, the fifth rotating body, and the sixth rotating body are arranged so that the rotation axes of the first rotating body, the second rotating body, the fifth rotating body, and the sixth rotating body extend vertically when the mounting main body is upright.

[0155] According to (24), the rotation axes of the first rotor, the second rotor, the fifth rotor, and the sixth rotor can be aligned.

[0156] (25) The coupling device according to (24), The telescopic device is The power transmission unit further includes a motion conversion mechanism (spindle unit SP) that is mechanically connected to the power transmission unit and converts the rotational power output from the power transmission unit into translational motion, The motion conversion mechanism includes a shaft member (spindle 173) and a cylindrical member (sleeve 174) that translates along the axis of the shaft member as the shaft member rotates. the third rotating body and the seventh rotating body are mechanically connected to the power source; the fourth rotating body and the eighth rotating body are mechanically connected to the shaft member of the motion converting mechanism, When the angle is an acute angle between an acute angle and an obtuse angle, the motion conversion mechanism is configured so that when the angle becomes larger, a force acts on the shaft member in a direction opposite to the direction of gravity.

[0157] According to (25), it is possible to prevent the support structure for supporting the shaft member of the motion conversion mechanism from becoming large.

[0158] (26) A coupling device according to (24) or (25), The telescopic device is The power transmission unit further includes a motion conversion mechanism (spindle unit SP) that is mechanically connected to the power transmission unit and converts the rotational power output from the power transmission unit into translational motion, The motion conversion mechanism includes a shaft member (spindle 173) and a cylindrical member (sleeve 174) that translates along the axis of the shaft member as the shaft member rotates. the third rotating body and the seventh rotating body are mechanically connected to the power source; the fourth rotating body and the eighth rotating body are mechanically connected to the shaft member of the motion converting mechanism, A coupling device in which, when the angle formed is the acute angle between the acute angle and the obtuse angle, the first rotating body and the second rotating body are configured so that, when the angle formed becomes larger, a thrust force acting from the first rotating body to the second rotating body acts on the shaft member in a direction opposite to the direction of gravity.

[0159] According to (26), it is possible to prevent the support structure for supporting the shaft member of the motion conversion mechanism from becoming large.

[0160] (27) The coupling device according to (26), The fifth rotating body and the sixth rotating body are configured so that when the angle they form increases, a thrust force acting from the fifth rotating body to the sixth rotating body acts on the shaft member in a direction opposite to the direction of gravity.

[0161] According to (27), it is possible to further prevent the support structure for supporting the shaft member of the motion conversion mechanism from becoming large.

[0162] This application is based on a Japanese patent application (Patent Application No. 2020-102714) filed on June 12, 2020, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0163] 1. Electric prosthetic limb (joint device) 110 knee lower member (first member) 120 Knee-upper member (second member) 130 Knee joint mechanism (articulation part) 140 Telescopic device 173 Spindle (shaft member) 174 Sleeve (tubular member) 181 1st shaft (3rd rotating body, 7th rotating body) 182 2nd shaft (4th rotor, 8th rotor) 183 First drive gear (first rotating body) 184 1st driven gear (2nd rotating body) 185 2nd drive gear (5th rotating body) 186 2nd driven gear (6th rotating body) 210 First interrupting mechanism 211 First Interrupted Section 212 Second Interrupted Section 220 Second interrupting mechanism 221 Third Interruption 222 Fourth Interruption 241 Second operating rod (operating part, operating element) 241c Large diameter part (extension part) 241c1 1st large diameter part (1st extension part, 2nd extension part) 241c2 Second large diameter part (first extension part, second extension part) 241c3 Third large diameter part (first extension part, second extension part) 242 Second servo motor (drive unit) 271 Roller (engagement element, engagement body) 272 pins (operating part, actuator, advance / retractor) 274 Retainer (operation part, actuator, engager) 281 Roller (engagement element, engagement body) 282 Retainer (operation part, actuator, engager) 282c Rubber ball (intervening part) 282d O-ring (intervening part) 283 Pin (operating part, actuator, advance / retractor) 284 Guide (operating part, actuator) S2 2nd internal space T-speed transmission T1 First transmission mechanism T2 Second transmission mechanism SP Spindle unit (motion conversion mechanism)

Claims

[Claim 1] A first member; A second member; a connecting portion that connects the first member and the second member so as to change an angle formed between the first member and the second member; A joint device including an expansion and contraction device that can expand and contract the angle formed between the first member and the second member, The telescopic device is A power source and a power transmission unit that transmits power from the power source, The power transmission unit is a first power transmission path that transmits the power at a first speed ratio; a second power transmission path that transmits the power at a second speed ratio different from the first speed ratio.

Images