Joint device

Abstract

A motorized prosthetic leg (1) comprises: a below-knee member (110); an above-knee member (120); a knee joint mechanism (130) coupling the below-knee member (110) and the above-knee member (120) such that the angle therebetween can be changed; and an expansion / contraction device (140) capable of changing the angle between the below-knee member (110) and the above-knee member (120) through expansion and contraction, wherein one side of the expansion / contraction device (140) in the extension direction is mechanically connected to the below-knee member (110), and the other side is mechanically connected to the above-knee member (120). When the smaller minimum angle among the angle formed by the below-knee member (110) and the above-knee member (120) about a rotary part (135) of the knee joint mechanism (130) is a second angle (θ2), at least a part of the expansion / contraction device (140) is disposed on a first angle (θ1) side.

Description

Coupling Device

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

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

[0003] Japanese Patent Application Publication No. 11-19105

[0004] However, the prosthetic limb 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 that allows the joint section to be extended and bent by means of an extension device.

[0006] The present invention provides a coupling device comprising: a first member; a second member; a connecting portion that connects the first member and the second member in a manner that allows the angle between them to be changed; and an extension device that is mechanically connected to the first member on one side in an extension direction and mechanically connected to the second member on the other side, and that can change the angle between the first member and the second member by expanding and contracting, wherein, of the angles formed between the first member and the second member around the connecting axis of the connecting portion, one side of one circumference is defined as a first angle and the other side is defined as a second angle, and when the second angle is defined as the smaller of the first angle and the second angle within the range of relative movement between the first member and the second member, at least a portion of the extension device is arranged on the side of the first angle.

[0007] The present invention also provides a coupling device comprising: a first member; a second member; a connecting portion that connects the first member and the second member in a manner that allows the angle between them to be changed; and an extension device that is mechanically connected to the first member on one side in an extension direction and to the second member on the other side, and that can change the angle between the first member and the second member by expanding and contracting, wherein the extension device comprises a motion conversion mechanism having an axial member and a tubular member that moves in translation along the axis of the axial member as the axial member rotates, and wherein, of the angles between the first member and the second member around the connecting axis of the connection portion, one side of one revolution is defined as a first angle and the other side is defined as a second angle, and when the smaller of the first angle and the second angle within the range of relative movement between the first member and the second member is defined as the second angle, the extension device is configured so that a tensile force acts on the axial member when the second angle becomes larger.

[0008] According to the present invention, the connecting portion can be extended and bent by the telescopic device.

[0009] 9 is a perspective view of an electric prosthetic leg according to a first embodiment of the present invention, as seen from an oblique front. It is a diagram showing a power transmission unit of the electric prosthetic leg of FIG. 1. It is a diagram showing a first speed change state in the power transmission unit of FIG. 2, in which the first interrupting unit of the first interrupting mechanism is in a forced free state and the third interrupting unit of the second interrupting mechanism is in a power transmittable state. It is a diagram showing a second speed change state in the power transmission unit of FIG. 2, in which the first interrupting unit of the first interrupting mechanism is in a power transmittable state and the third interrupting unit of the second interrupting mechanism is in a forced free state. It is a cross-sectional view taken along line A-A in FIG. 3. It is a cross-sectional view taken along line B-B in FIG. 3. It is a perspective view of line C-C in FIG. 3. It is a perspective view of line D-D in FIG. 3. (A) to (F) are diagrams showing the movements of a person and an electric prosthetic leg when ascending steps. It is a diagram explaining the power when the knee joint mechanism is extended from a bent state when ascending steps ((A) → (B) in FIG. 9). It is a diagram explaining the power when the knee joint mechanism is bent from an extended state when ascending steps ((D) → (E) in FIG. 9). 18 is a diagram showing the movements of a human and an electric prosthetic leg when ascending steps, walking on level ground, and descending steps. FIG. 19 is a diagram explaining the power when the knee joint mechanism is bent from an extended state while attenuating an external force when descending steps or walking on level ground. FIG. 20 is a diagram showing an electric prosthetic leg of a modified example, and is a diagram explaining the power when the knee joint mechanism is extended from a flexed state while attenuating an external force when walking on level ground. FIG. 21 is a diagram showing a power transmission unit of an electric prosthetic leg of a second embodiment of the present invention. FIG. 22 is a diagram showing a power transmission unit of an electric prosthetic leg of a third embodiment of the present invention. FIG. 23 is a cross-sectional view of a two-way clutch. FIG. 24 is a perspective view showing an example of a retainer shown in FIG. 17 (including rollers, guides, and rubber balls). FIG. 25 is a perspective view showing another example of the retainer shown in FIG. 17 (including rollers, guides, and O-rings). 16A and 16B are diagrams showing the operation of the second operating mechanism 240 in the second and fourth interrupting units shown in FIG. 16A, where (A) is a diagram showing the second and fourth interrupting units in an OFF state, (B) is a diagram showing the second interrupting unit in an ON state and the fourth interrupting unit in an OFF state, and (C) is a diagram showing the second interrupting unit in an OFF state and the fourth interrupting unit in an ON state. (A) is a cross-sectional view taken along line A-A in FIG. 16A showing the second interrupting unit in an OFF state, and (B) is a diagram showing the position of the second operating rod 241 at that time. (A) is a cross-sectional view taken along line A-A in FIG. 16A showing the second interrupting unit in an ON state from OFF, and (B) is a diagram showing the position of the second operating rod 241 at that time.16A is a cross-sectional view taken along the line A-A in FIG. 16A showing the second interlocking unit shown in FIG. 16 in a forward rotation ON state, and (B) is a diagram showing the position of the second operating rod 241 at that time. (A) is a cross-sectional view taken along the line A-A in FIG. 16A showing the second interlocking unit shown in FIG. 16 in a reverse rotation ON state, and (B) is a diagram showing the position of the second operating rod 241 at that time. (A) is a cross-sectional view taken along the line A-A in FIG. 16A showing the second interlocking unit shown in FIG. 16 in a forward rotation ON state, and (B) is a diagram showing the position of the second operating rod 241 at that time. (A) is a cross-sectional view taken along the line A-A in FIG. 16A showing the state in which the second interlocking unit shown in FIG. 16A has been operated from ON to OFF, and (B) is a diagram showing the position of the second operating rod 241 at that time. (B) is a cross-sectional view showing the position of the second operating rod 241 at that time. (C) is a perspective view of an electric prosthetic leg according to a fourth embodiment of the present invention, as seen obliquely from the front. (D) is an exploded perspective view of the electric prosthetic leg of FIG. 27A. (E) is a cross-sectional view of the electric prosthetic leg of FIG. 27A. (F) is a cross-sectional view of the main parts of the electric prosthetic leg of FIG. 27A showing the extended state. Fig. 28 is a cross-sectional view of a main part showing the electric prosthetic leg of Fig. 27 during bending. Fig. 28 is a cross-sectional view of a main part showing the maximum bending state of the electric prosthetic leg of Fig. 27. Fig. 28 is an explanatory view showing the maximum bending state of the electric prosthetic leg of Fig. 27, explaining the angle formed between the above-knee member 120 and the below-knee member 110, and the load acting on the spindle unit SP.

[0010] 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 are 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 as L, the right as R, the top as U, and the bottom as D.

[0011] [Electric prosthetic leg] 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 a knee, and includes 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 in a manner that allows the angle between them to be changed, an extension and contraction device 140 that can change the angle between the below-knee member 110 and the above-knee member 120 by extending and contracting, and a battery (not shown).

[0012] The above-knee member 120 comprises an upper wall portion 122 provided with an adapter 121 that is connected to a socket not shown, and a pair of upper side wall portions 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.

[0013] The knee below-side member 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 an approximately U-shape that opens upward when viewed from the front-to-back direction.

[0014] 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 about 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.

[0015] An extension device 140 that can change the angle between the above-knee member 120 and the below-knee member 110 is provided in the space formed between the above-knee member 120 and the below-knee member 110. The extension device 140 extends in the vertical direction, and, as will be described in detail later, one side in the extension direction is mechanically connected to the above-knee member 120, and the other side in the extension direction is mechanically connected to the below-knee member 110. Note that the term "mechanically connected" is a concept that includes a direct connection and a connection via another member.

[0016] The extension / contraction 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 external forces input from the spindle unit SP.

[0017] The transmission T is equipped with a transmission case 160 that is rectangular when viewed from the front-to-rear direction and includes a top plate 161, a bottom plate 162, a middle plate 163 arranged parallel to the top plate 161 and the bottom plate 162, and a pair of side plates 164 connecting 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 pivoting part (not shown) so as to be pivotable but immovable. That is, the extension and contraction device 140 mechanically connects the transmission case 160 to the knee-below member 110 via the lower pivoting part (not shown).

[0018] The motor M is disposed in front of and above the top plate 161 of the transmission case 160 so that the output shaft 171 passes through the top plate 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 rotation of the spindle 173 causes the sleeve 174 to translate along the axis of the spindle 173 (a line passing through the axis and extending in the extension direction).

[0019] 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 the base 174a of the sleeve 174 pivotable about the upper pivoting portion 125. That is, in the extension and contraction device 140, the base 174a of the sleeve 174 is mechanically connected to the above-knee member 120 by the upper pivoting 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. In addition, the translational movement of the sleeve 174 away from the transmission T is sometimes referred to as the extension operation of the spindle unit SP, and conversely, the translational movement of the sleeve 174 towards the transmission T is sometimes referred to as the contraction operation of the spindle unit SP.

[0020] 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 above-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 below-knee member 110, to which the transmission T is attached, and the above-knee member 120, to which the sleeve 174 is attached, to rotate about the rotating part 135. This changes the angle formed between the above-knee member 120 and the below-knee member 110.

[0021] Here, the angle between the above-knee member 120 and the below-knee member 110 is an angle defined by a first imaginary line L1 connecting the center of the rotating part 135 of the knee joint mechanism 130 and the adapter 121 of the above-knee member 120, and a second imaginary line L2 extending vertically downward through the center of the rotating part 135 of the knee joint mechanism 130 and the below-knee member 110. Of the angles formed between the below-knee member 110 and the above-knee member 120 around the rotating part 135 of the knee joint mechanism 130, one side of one revolution is defined as a first angle θ1, and the other side is defined as a second angle θ2. If the second angle θ2 is the smaller of the first angle θ1 and the second angle θ2, whichever is the smaller minimum angle within the range of relative movement of the below-knee member 110 and the above-knee member 120, the angle formed by the back of the knee of the user of the electric prosthetic leg 1 is the second angle θ2. The first angle θ1 has a value of about 170° to 310°, and the second angle θ2 has a value of about 50° to 190°.

[0022] 2 shows the knee joint mechanism 130 in an extended state, with the first angle θ1 being approximately 170° and the second angle θ2 being approximately 190°. In the electric prosthetic leg 1 of this embodiment, at least a portion of the extension device 140 is provided on the first angle θ1 side (shin side) with respect to the second imaginary line L2. More specifically, in this embodiment, the motor M of the extension device 140 is provided on the first angle θ1 side (shin side) with respect to the second imaginary line L2. Meanwhile, the spindle unit SP of the extension device 140 is provided on the second angle θ2 side (calf side) with respect to the second imaginary line L2. Therefore, when the second angle θ2 decreases and the first angle θ1 increases, the length of the spindle unit SP decreases, and the knee joint mechanism 130 bends. On the other hand, when the second angle θ2 increases and the first angle θ1 decreases, the length of the spindle unit SP increases, and the knee joint mechanism 130 extends. This makes it possible to narrow the minimum setting range of the second angle θ2 compared to when both the motor M and the spindle unit SP are located on the side of the second angle θ2. This therefore enables the user of the electric prosthetic leg 1 to bend their knee more deeply.

[0023] 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.

[0024] Such a transmission T, by providing two power transmission paths with different gear ratios, can 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 either 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.

[0025] The first speed change ratio is the ratio of the post-shift 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-shift rotation speed, which is the rotation speed on the side opposite to the motor M of the first speed change mechanism T1. The second speed change ratio is the ratio of the post-shift 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-shift rotation speed, which is the rotation speed on the side opposite to the motor M of the second speed change mechanism T2.

[0026] For example, when the first speed change ratio of the first speed change mechanism T1 is smaller than 1, the rotation speed on the side opposite the motor M (the side opposite the spindle unit SP) decreases compared to the rotation speed on the side opposite the motor M, resulting in an increase in torque. When the second speed change ratio of the second speed change mechanism T2 is larger than 1, the rotation speed on the side opposite the motor M (the side opposite the spindle unit SP) increases compared to the rotation speed on the side opposite the motor M, resulting in a decrease in torque. 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 speed change mechanism T1 is disposed above the second speed change mechanism T2.

[0027] The first speed change mechanism T1 and the second speed change 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 so as to be rotatable therewith via a coupling 187 that allows for axial center error, and the second shaft 182 is connected to the spindle 173 of the spindle unit SP so as to be rotatable therewith via a key 188 and key grooves 182a and 173a. 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.

[0028] 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 rotatable relative to the first shaft 181, and the first driven gear 184 is supported by the second shaft 182 so as to be rotatable relative to the first shaft 182. 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 can cause the spindle unit SP to extend and retract at low speed with high torque.

[0029] 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 can extend and retract the spindle unit SP at high speed and with low torque.

[0030] The first interrupting mechanism 210 comprises a first interrupting portion 211 provided between the first drive gear 183 and the first shaft 181, and a second interrupting portion 212 provided between the first driven gear 184 and the second shaft 182.

[0031] The second interrupting mechanism 220 includes a third interrupting portion 221 provided between the second drive gear 185 and the first shaft 181, and a fourth interrupting portion 222 provided between the second driven gear 186 and the second shaft 182.

[0032] 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.

[0033] 5 to 8, each of the connecting / disconnecting portions 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 peripheral surface of the shafts 181 and 182 and the inner peripheral 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 transmitted rotation directions 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.

[0034] 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.

[0035] 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.

[0036] 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 vertically when the user of the electric prosthetic leg 1 is standing upright.

[0037] The first operating rod 231 has a rack 231a at 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 the driving of the first servo motor 232. Note that 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.

[0038] The second operating rod 241 has a rack 241a at its lower end. 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.

[0039] The pin 272 of each of the intermittent 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 pin 272 in the inward forced free release position and large diameter portions 231c and 241c that push the pin 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, seamlessly connecting the small diameter portions 231b and 241b and the large diameter portions 231c and 241c.

[0040] In this embodiment, a first speed change state in which the first operating rod 231 and the second operating rod 241 are positioned in an upper position, and a second speed change state in which the first operating rod 231 and the second operating rod 241 are positioned in a lower position are provided. 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 portion 221 and the fourth connecting 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.

[0041] An external force in the bending direction input from the spindle unit SP is transmitted to the rotary damper 250 via the first speed change mechanism T1. Specifically, an input gear 252 that meshes with the first drive gear 183 of the first speed change mechanism T1 is provided on an input shaft 251 of the rotary damper 250. In addition, a one-way clutch 253 that transmits rotation in one direction of the first speed change 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 speed change 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.

[0042] 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.

[0043] 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 state while a load is applied to the electric prosthetic leg 1.

[0044] At this time, the transmission T is in a second speed change state in which the first operating rod 231 and the second operating rod 241 are positioned in the lower position. In the second speed change 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 speed change mechanism T1.

[0045] In this state, when the motor M is rotated in the first direction (direction D1 in FIG. 10 ), the power of the motor M is transmitted to the first shaft 181, the first interrupter 211 of the first interrupter mechanism 210, the first drive gear 183, the first driven gear 184, the second interrupter 212 of the first interrupter mechanism 210, the second shaft 182, and the spindle unit SP. This causes the sleeve 174 to translate away from the transmission T, extending (increasing) the length of the spindle unit SP of the telescopic device 140. At the same time, the above-knee member 120, to which the sleeve 174 is attached, rotates about the pivot 135 relative to the below-knee member 110, to which the transmission T is attached, increasing the second angle θ2 and decreasing the first angle θ1. As a result, the knee joint mechanism 130 extends. Furthermore, since this extension power is a power that is made high 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.

[0046] 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 leg, 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.

[0047] 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 connecting / disconnecting portion 211 and the second connecting / disconnecting portion 212 of the first connecting / disconnecting 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.

[0048] 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 closer to the transmission T, shortening (reducing) the length of the spindle unit SP of the extension device 140. At the same time, the below-knee member 110, to which the transmission T is attached, rotates about the pivot 135 relative to the above-knee member 120, to which the sleeve 174 is attached, thereby decreasing the second angle θ2 and increasing the first angle θ1. As a result, the knee joint mechanism 130 flexes. Furthermore, this bending power is a power that has been reduced in torque when it is accelerated by the second speed change mechanism T2, so that the knee joint mechanism 130 can be bent quickly.

[0049] Furthermore, when descending the stairs 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.

[0050] At this time, the transmission T is in a second speed change state in which the first operating rod 231 and the second operating rod 241 are positioned in the lower position. In the second speed change 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 speed change mechanism T1.

[0051] 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.

[0052] 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.

[0053] As shown in Figure 14, the electric prosthetic leg 1 of the modified example differs from the above embodiment in that it is equipped 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.

[0054] An external force in the extension direction input from the spindle unit SP is transmitted to the second rotary damper 260 via the second speed change mechanism T2. Specifically, an input gear 262 that meshes with the second drive gear 185 of the second speed change mechanism T2 is provided on an 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 speed change 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).

[0055] 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.

[0056] 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.

[0057] 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 omitted or may be referred to by using the same reference numerals as in the first embodiment.

[0058] 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 in 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.

[0059] 15 , like the transmission T of the first embodiment, the transmission T of the second 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.

[0060] 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 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.

[0061] 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.

[0062] 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.

[0063] These interrupting portions 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.

[0064] As shown in FIG. 16, the transmission T of the third embodiment includes a first speed change mechanism T1, a second speed change mechanism T2, a first interrupting mechanism 210, and a second interrupting mechanism 220, similar to the transmission T of the second embodiment.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 17, each of the interrupting portions 211, 221 of the second embodiment and each of the interrupting portions 212, 222 of the third embodiment is configured using a two-way clutch 280 having a forced free function. 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 a predetermined interval, a plurality of pins 283 (three in this embodiment) that radially penetrate the shafts 181, 182 and are operated by the first operating mechanism 230 or the second operating mechanism 240 to a forced free position and a forced free release position, and a plurality of guides 284 (three in this embodiment) that are provided on the retainer 282 and that determine the relative rotational position of the retainer 282 with respect to the shafts 181, 182 when the pins 283 are in the forced free position.

[0070] 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.

[0071] In other words, when the roller 281 is held in the circumferential center of the flat portions 281a, 282a, the roller 281 does not mesh with the outer peripheral surfaces of the shafts 181, 182 and the inner peripheral surfaces of the gears 183 to 186, and relative rotation between the shafts 181, 182 and the gears 183 to 186 is permitted (forced free state).

[0072] 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).

[0073] As shown in Figure 18, the retainer 282 is ring-shaped and rotatable relative to the shafts 181, 182 and gears 183 to 186, and has a plurality of roller holding portions 282a that hold the roller 281 and a plurality of guide holding portions 282b that hold the guide 284.

[0074] Additionally, multiple rubber balls 282c are embedded at predetermined intervals around the circumferential surface of the retainer 282. These rubber balls 282c generate appropriate friction between the gears 183 to 186 and the retainer 282, preventing unintended spinning in the forced free release state. Note that the member that generates friction between the gears 183 to 186 and the retainer 282 may be an O-ring 282d as shown in FIG. 19. Additionally, although the rubber balls 282c and the O-ring 282d are effective in preventing spinning, they may be omitted.

[0075] 17 , the pin 283 has a conical protrusion 283 a on its radially outer end, and the guide 284 has a conical recess 284 a on its radially inner end face that fits (engages) with the protrusion 283 a. When the protrusion 283 a of the pin 283 fits into the recess 284 a of the guide 284, the guiding action of the pin 283 and the guide 284 positions the retainer 282 at a predetermined position where the relative rotation position with respect to the shafts 181, 182 is forced free.

[0076] 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.

[0077] In the following, the operation of the second operating mechanism 240 that simultaneously controls the interrupting units 212, 222 of the third embodiment will be described with reference to Fig. 20. As shown in Fig. 20, the interrupting units 212, 222 are switched by the 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).

[0078] 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 outward radial direction, while the third large diameter portion 241c3 pushes the pin 283 of the fourth interrupting portion 222 in the outward radial direction, thereby turning the second interrupting portion 212 and the fourth interrupting portion 222 to the off state.

[0079] 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.

[0080] 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 turning the second interrupting portion 212 to the off state and the fourth interrupting portion 222 to the on state.

[0081] Although not shown, each of the intermittent portions 211, 221 of the second embodiment can also be switched between a forced free state and a forced free release state by a first operation mechanism 230. A 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 ). When in the upper position, the first operating rod 231 of the first operating mechanism 230 pushes the pins 283 of the first intermittent portion 211 and the third intermittent portion 221 in the outward radial direction, thereby turning the first intermittent portion 211 and the third intermittent portion 221 to the off state; when in the middle position, it pushes the pin 283 of the third intermittent portion 221 in the outward radial direction while allowing the pin 283 of the first intermittent portion 211 to return in the inward radial direction, thereby turning the first intermittent portion 211 to the on state and the third intermittent portion 221 to the off state; and when in the lower position, it pushes the pin 283 of the first intermittent portion 211 in the outward radial direction while allowing the pin 283 of the third intermittent portion 221 to return in the inward radial direction, thereby turning the first intermittent portion 211 to the off state and the third intermittent portion 221 to the on state.

[0082] Next, the operation of the two-way clutch 280 will be described with reference to Figures 21 to 26 using the second interrupting part 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 interrupting part 212 will be described as an example.

[0083] 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 of the flat portion 282a, so the roller 281 does not mesh with the outer circumferential surface portion of the second shaft 182 and the inner circumferential surface portion of the first driven gear 184, and an OFF state is established in which relative rotation between the second shaft 182 and the first driven gear 184 is permitted.

[0084] 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 outward radial direction to a position where the first small diameter portion 241b1 allows the pin 283 to return inward in the inward radial direction. In Fig. 22, the pin 283 has already moved inward in the timing when relative rotation between the second shaft 182 and the first driven gear 184 occurs, but in reality, the guide 284 of the retainer 282, which rotates together with the first driven gear 184, pushes the pin 283 back inward in the inward radial direction with the inclined surface of the recess 284a.

[0085] 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 inward radial 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.

[0086] 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 inward radial 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.

[0087] 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 inward radial direction to a position where the first large diameter portion 241c1 pushes the pin 283 outward radially, 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 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.

[0088] Although detailed explanation will be omitted, the bidirectional clutch 280 of the fourth interrupting part 222 of the third embodiment and the first interrupting part 211 and third interrupting part 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 includes the second interrupting part 212 and the fourth interrupting part 222 on the downstream side. Therefore, when the interrupting parts 212, 222 are located in the OFF state, fewer rotating bodies are involved, resulting in a more agile operation of the electric prosthetic leg 1.

[0089] 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.

[0090] 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 force stored when the knee is flexed. Details of each difference will be explained below in order.

[0091] 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 side surfaces of the main frame 311, and a detachable rear cover 313 that can be opened and closed and covers the rear opening of the main frame 311.

[0092] The upper-knee member 120 is attached to the upper part of the main frame 311 via a pivoting part 135, and the leg part 111 is attached to the lower part of the main frame 311. A unitized extension device 140 is also incorporated within the main frame 311. The extension device 140 extends in the vertical direction, with one side in the extension direction mechanically connected to the above-knee member 120 and the other side in the extension direction mechanically connected to the below-knee member 110. Note that the term "mechanically connected" encompasses both a direct connection and a connection via another member. More specifically, the extension device 140 has an upper end of a link member 320 (described below) located on one side in the extension direction mechanically connected to the above-knee member 120 by a second pivoting part 322, and a unit case 315 located on the other side in the extension direction mechanically connected to the main frame 311, i.e., the below-knee member 110, via a bracket 316.

[0093] 29 , the transmission T includes a first speed change mechanism T1, a second speed change mechanism T2, a first interrupter mechanism 210, and a second interrupter mechanism 220. The transmission T of the fourth embodiment differs from the transmissions T of the second and third embodiments in that the first speed change mechanism T1 is disposed below the second speed change mechanism T2.

[0094] 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.

[0095] 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.

[0096] 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. In this embodiment as well, when the spindle 173 rotates in one direction by receiving the rotational power of the motor M transmitted by the transmission T, the sleeve 174 moves translationally away from the transmission T, and when the spindle 173 rotates in the other direction, the sleeve 174 moves translationally toward the transmission T. Note that the translational movement of the sleeve 174 away from the transmission T may be referred to as an extension operation of the spindle unit SP, and conversely, the translational movement of the sleeve 174 toward the transmission T may be referred to as a contraction operation of the spindle unit SP.

[0097] As shown in Figures 29 to 32, in the electric prosthetic leg 1 of the fourth embodiment, the spindle unit SP is positioned in front of the rotating part 135, and the knee joint mechanism 130 is bent in response to the extension operation of the spindle unit SP, and the knee joint mechanism 130 is extended in response to the contraction operation of the spindle unit SP.

[0098] Figure 30 shows the knee joint mechanism 130 in an extended state, with the first angle θ1 being approximately 170° and the second angle θ2 being approximately 190°. Figure 31 shows the knee joint mechanism 130 in a flexed state, with the first angle θ1 being approximately 260° and the second angle θ2 being approximately 120°. Figure 32 shows the knee joint mechanism 130 in a maximally flexed state, with the first angle θ1 being approximately 310° and the second angle θ2 being approximately 50°. Figure 33 shows the electric prosthetic leg 1 of the fourth embodiment in a maximally flexed state, and is an explanatory diagram illustrating the angle between the above-knee member 120 and the below-knee member 110, and the operation and load of the spindle unit SP.

[0099] As in the first to third embodiments, the angle between the above-knee member 120 and the below-knee member 110 is defined by a first imaginary line L1 connecting the center of the rotating part 135 of the knee joint mechanism 130 and the adapter 121 of the above-knee member 120, and a second imaginary line L2 passing through the center of the rotating part 135 of the knee joint mechanism 130 and the below-knee member 110 and extending vertically downward. Furthermore, among the angles formed between the below-knee member 110 and the above-knee member 120 around the rotating part 135 of the knee joint mechanism 130, one side of one revolution is defined as a first angle θ1 and the other side as a second angle θ2, and the second angle θ2 is defined as the smaller of the first angle θ1 and the second angle θ2, whichever is the smaller minimum angle within the range of relative movement between the below-knee member 110 and the above-knee member 120. The second angle θ2 is the angle formed by the back of the knee of the user of the electric prosthetic leg 1. The first angle θ1 has a value of approximately 170° to 310°, and the second angle θ2 has a value of approximately 50° to 190°.

[0100] In the electric prosthetic leg 1 of this embodiment, at least a portion of the extension device 140 is disposed on the side of the first angle θ1 (shin side) with respect to the second imaginary line L2. More specifically, the spindle unit SP of the extension device 140 is disposed on the side of the first angle θ1 (shin side) with respect to the second imaginary line L2. That is, while the spindle unit SP in the first to third embodiments was disposed on the side of the second angle θ2 (calf side) with respect to the second imaginary line L2, the spindle unit SP in the fourth embodiment is disposed on the side of the first angle θ1 (shin side) with respect to the second imaginary line L2. Therefore, when the second angle θ2 decreases and the first angle θ1 increases, the length of the spindle unit SP increases, and the knee joint mechanism 130 bends. On the other hand, when the second angle θ2 increases and the first angle θ1 decreases, the length of the spindle unit SP decreases, and the knee joint mechanism 130 extends. In other words, the extension / contraction device 140 is provided so that the length of the spindle unit SP decreases (becomes smaller) when the second angle θ2 increases.

[0101] On the other hand, in this embodiment, the motor M of the extension / contraction device 140 is provided on the side (calf side) of the second angle θ2 with respect to the second virtual line L2.

[0102] With this configuration, as shown by the hollow arrow in FIG. 33 , during high-torque operation to extend the knee joint mechanism 130 from a bent state (from (A) to (B) in FIG. 9 ), when the spindle 173 rotates to the other side, the sleeve 174 moves translationally toward the transmission T, and a pulling force acts on the spindle 173 from the sleeve 174, generating a tensile load (tensile force) in the direction of gravity on the spindle 173, as shown by the hatched arrow in FIG. 33 . Therefore, during high-torque operation to extend the knee joint mechanism 130 from a bent state, a pulling force acts on the spindle 173 of the spindle unit SP from the sleeve 174 side, generating a tensile load, thereby preventing buckling deformation of the spindle 173. The spindle 173 is made of a material (e.g., metal) that is stronger in tension than in compression, and therefore has improved durability compared to materials that are subjected to compressive forces during this operation. In other words, when the knee joint mechanism 130 is extended from a bent state, the second angle θ2 increases and the first angle θ1 decreases. Therefore, it can be said that the extension / contraction device 140 of this embodiment is provided so that a tensile force acts on the spindle 173 of the spindle unit SP when the second angle θ2 increases.

[0103] 29, the spindle 173 is integrally connected to a second shaft 182, which is integrated with a first driven gear 184 and a second driven gear 186. The second shaft 182 is supported by the unit case 315 via a pair of upper and lower bearings BRG. When the second angle θ2 between the above-knee member 120 and the below-knee member 110 increases and the first angle θ1 decreases as the spindle unit SP contracts, a force is applied from the sleeve 174 to the spindle 173, pulling it up in the direction opposite to gravity, thereby reducing the load on the bearing BRG. This prevents the bearing BRG from becoming too large.

[0104] Furthermore, all of the gears 183 to 186 are helical gears, and when the motor M is driven, a thrust force acts from the drive gears 183 and 185 to the driven gears 184 and 186. By configuring the gears 183 to 186 so that this thrust force acts on the 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 the spindle 173.

[0105] 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 is 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.

[0106] As mentioned above, Figure 30 shows the extended state of the electric prosthetic leg 1 of the fourth embodiment, Figure 31 shows the extended state of the electric prosthetic leg 1, and Figure 32 shows the maximum bent state of the electric prosthetic leg 1. It should be noted that the maximum bent state shown in Figure 32 is not reached while walking with the electric prosthetic leg 1. In Figure 30, the first stopper 342 attached to the support piece 341 supporting the second rotation part 322 abuts against the position restriction pin 350, preventing the knee joint mechanism 130 from bending in the opposite direction. Also, in Figure 32, the second stopper 343 attached to the above-knee member 120 abuts against the position restriction pin 350, preventing the knee joint mechanism 130 from bending further from the maximum bent state. In Figures 30 to 32, the symbol B denotes a battery that supplies power to the motor M.

[0107] 29 , in the electric prosthetic leg 1 of the fourth embodiment, the battery B is provided on the side of the second imaginary line L2 at the first angle θ1 (shin side). That is, the battery B is provided together with the spindle unit SP on the side of the second imaginary line L2 at the first angle θ1 (shin side). On the other hand, the motor M is provided on the side of the second imaginary line L2 at the second angle θ2 (calf side). In other words, the battery B and the motor M are provided on opposite sides of the spindle unit SP.

[0108] 29 to 32, an extension assist mechanism 330 is provided between the upper end of the link member 320 and the above-knee member 120. The extension assist mechanism 330 assists extension by using a force stored when the knee joint mechanism 130 is bent. The extension assist mechanism 330 includes a pressing portion 332 that presses the upper end of the link member 320 by using 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 includes a small-diameter outer periphery 323a centered on the second rotating portion 322, a large-diameter outer periphery 323b that is a long distance from the second rotating portion 322, and a connecting outer periphery 323c that seamlessly connects the small-diameter outer periphery 323a and the large-diameter outer periphery 323b.

[0109] 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 bends, 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.

[0110] 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.

[0111] In the transmission T of the fourth embodiment, an example has been given of a configuration 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, it may also be a configuration 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.

[0112] 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.

[0113] For example, in the above embodiment, a prosthetic leg device (electric prosthetic leg) applied to a knee joint is 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.

[0114] Furthermore, the extension / contraction 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 embodiments 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.

[0115] 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.

[0116] (1) A joint device (electric prosthetic leg 1) comprising: a first member (below-knee member 110); a second member (above-knee member 120); a connecting section (knee joint mechanism 130) that connects the first member and the second member so as to be able to change the angle between them; and an extension device (extension device 140) that is mechanically connected to the first member on one side in the extension direction and to the second member on the other side, and that can change the angle between the first member and the second member by expanding and contracting; wherein, among the angles formed between the first member and the second member around the connecting axis (rotating section 135) of the connecting section, one side of one revolution is defined as a first angle (first angle θ1) and the other side is defined as a second angle (second angle θ2); and, of the first angle and the second angle, the smaller of the minimum angles formed within the range in which the first member and the second member move relative to each other is defined as the second angle; A coupling device, wherein at least a portion of the expansion device is disposed on the first corner side.

[0117] According to (1), the connecting portion can be extended and bent by the telescopic device. Since the second corner side is the side with the smallest angle, by disposing at least a part of the telescopic device on the opposite side, the first corner side, the setting range of the smallest angle on the second corner side can be made smaller.

[0118] (2) The joint device according to (1), wherein the extension device is provided so that the length in the extension direction decreases when the second angle increases.

[0119] According to (2), when the second angle increases, the extension length of the expansion device decreases (contracts), causing the joint device to bend.

[0120] (3) The coupling device according to (1) or (2), wherein the telescopic device has a power source (motor M) that outputs rotational power, and a motion conversion mechanism (spindle unit SP) that converts the rotational power output from the power source into translational motion.

[0121] According to (3), power from the power source is output to the motion conversion mechanism, and the angle formed between the first member and the second member can be changed.

[0122] (4) The joint device according to (3), wherein the motion conversion mechanism is disposed on the first corner side.

[0123] According to (4), since the long motion conversion mechanism is disposed on the first corner side, the setting range of the minimum angle on the second corner side can be made smaller.

[0124] (5) The coupling device according to (3) or (4), wherein the motion conversion mechanism has a shaft member (spindle 173) and a tubular member (sleeve 174) that translates along the axis of the shaft member as the shaft member rotates.

[0125] According to (5), a motion conversion mechanism can be realized with a simple configuration.

[0126] (6) The coupling device according to (5), wherein the expansion device is provided so that a tensile force acts on the shaft member when the second angle increases.

[0127] According to (6), buckling deformation of the expansion device can be suppressed when the second angle becomes large.

[0128] (7) The coupling device according to any one of (3) to (6), wherein the power source is disposed on the second corner side.

[0129] According to (7), the size of the power source can be adjusted according to the setting range of the minimum angle on the second angle side.

[0130] (8) The coupling device according to any one of (3) to (7), further comprising an electric storage device that supplies electric power to the power source, the electric storage device being disposed on the first corner side.

[0131] According to (8), the power storage device can be appropriately arranged.

[0132] (9) The coupling device according to (8), wherein the motion conversion mechanism is disposed on the side of the first corner, and the power source is disposed on the side of the second corner.

[0133] According to (9), the power storage device, the motion conversion mechanism, and the power source can be arranged in a balanced manner.

[0134] (10) A joint device (electric prosthetic leg 1) comprising: a first member (below-knee member 110); a second member (above-knee member 120); a connecting portion (knee joint mechanism 130) that connects the first member and the second member so as to be able to change the angle between them; and an extension device (extension device 140) that is mechanically connected to the first member on one side in the extension direction and to the second member on the other side, and that can change the angle between the first member and the second member by expanding and contracting, wherein the extension device comprises a motion conversion mechanism (spindle unit SP) that has an axial member (spindle 173) and a tubular member (sleeve 174) that moves in translation along the axis of the axial member by rotation of the axial member; and the angle between the first member and the second member centered on the connecting axis of the connecting portion is set to a first angle (first angle θ1) on one side of one revolution and a second angle (second angle θ2) on the other side of one revolution, When the second angle is the smaller of the first angle and the second angle that is the smallest angle within the range of relative movement between the first member and the second member, the extension device is configured so that a tensile force acts on the shaft member when the second angle becomes larger.

[0135] According to (10), the connecting portion can be extended and bent by the extension device. Also, buckling deformation of the extension device can be suppressed when the second angle increases.

[0136] (11) The joint device according to any one of (1) to (10), which is a prosthetic device that is attached to a main body so that the first member is located on the distal side of the main body with respect to the second member.

[0137] According to (11), the joint device can be used as a prosthetic device.

[0138] (12) The joint device according to (11), wherein the prosthetic limb device is a prosthetic leg device that is attached to a leg of the attachment subject.

[0139] According to (12), the joint device can be used as a prosthetic leg device.

[0140] (13) The joint device according to (12), wherein the second member is attached to the thigh of the leg, and the connecting portion is provided to function as a knee joint between the thigh and the crus.

[0141] According to (13), the joint device can be used as a knee joint.

[0142] 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.

[0143] This application is based on a Japanese patent application (Patent Application No. 2021-098286) filed on June 11, 2021, the contents of which are incorporated herein by reference.

[0144] 1 Electric prosthetic leg (joint device) 110 Knee lower member (first member) 120 Knee upper member (second member) 130 Knee joint mechanism (connection portion) 140 Telescopic device 173 Spindle (shaft member) 174 Sleeve (cylindrical member) 181 First shaft (third rotating body, seventh rotating body) 182 Second shaft (fourth rotating body, eighth rotating body) 183 First drive gear (first rotating body) 184 First driven gear (second rotating body) 185 Second drive gear (fifth rotating body) 186 Second driven gear (sixth rotating body) 210 First interrupting mechanism 211 First interrupting part 212 Second interrupting part 220 Second interrupting mechanism 221 Third interrupting part 222 Fourth interrupting part 241 Second operation rod (operation section, operator) 241c Large diameter section (extension section) 241c1 First large diameter section (first extension section, second extension section) 241c2 Second large diameter section (first extension section, second extension section) 241c3 Third large diameter section (first extension section, second extension section) 242 Second servo motor (drive section) 271 Roller (engaging element, engaging element) 272 Pin (operating part, actuating element, reciprocating element) 274 Retainer (operating element, actuating element, engaging element) 281 Roller (engaging element, engaging element) 282 Retainer (operating element, actuating element, engaging element) 282c Rubber ball (interposed member) 282d O-ring (interposed member) 283 Pin (operating part, actuator, advance / retractor) 284 Guide (operating part, actuator) S2 Second internal space T Transmission T1 First transmission mechanism T2 Second transmission mechanism SP Spindle unit (motion conversion mechanism)

Claims

1. a first member, a second member, a connecting portion that connectably changes the angle formed between the first member and the second member, a telescopic device having one side in the extending direction mechanically connected to the first member and the other side mechanically connected to the second member, and capable of changing the angle formed between the first member and the second member by expanding and contracting, wherein the joint device comprises: of the angles formed between the first member and the second member about the connecting axis of the connecting portion, one side of one full turn is defined as a first formed angle and the other side is defined as a second formed angle, when, of the first formed angle and the second formed angle, the smaller of the minimum angles formed within the range in which the first member and the second member relatively move is defined as the second formed angle, the telescopic device is disposed at least partly on the first formed angle side. A joint device.

2. The joint device according to claim 1, wherein the telescopic device is provided such that the length in the extending direction decreases when the second formed angle increases. A joint device.

3. The joint device according to claim 1, wherein the telescopic device has a power source that outputs rotational power, and a motion conversion mechanism that converts the rotational power output from the power source into translational motion. A joint device.

4. The joint device according to claim 3, wherein the motion conversion mechanism is disposed on the first formed angle side. A joint device.

5. The joint device according to claim 3, wherein the motion conversion mechanism has a shaft member and a cylindrical member that moves translationally along the axis of the shaft member by rotation of the shaft member. A joint device.

6. The joint device according to claim 5, wherein the telescopic device is provided such that a tensile force acts on the shaft member when the second formed angle increases. A joint device.

7. The joint device according to claim 3, wherein the power source is disposed on the second formed angle side. A joint device.

8. The joint device according to claim 3, having a power storage device that supplies power to the power source, wherein the power storage device is disposed on the first formed angle side. A joint device.

9. The joint device according to claim 8, wherein the motion conversion mechanism is disposed on the first formed angle side, and the power source is disposed on the second formed angle side. A joint device.

10. a first member, a second member, a connecting portion that connectably changes the angle formed between the first member and the second member, A joint device comprising a telescopic device that is mechanically connected to the first member on one side in the extending direction, mechanically connected to the second member on the other side, and can change the angle formed by the first member and the second member by expanding and contracting. The telescopic device is provided with a motion conversion mechanism having a shaft member and a cylindrical member that translates along the axis of the shaft member by rotation of the shaft member. Of the angles formed by the first member and the second member around the connecting axis of the connecting portion, one side of one circumference is defined as the first formed angle, and the other side is defined as the second formed angle. When the smaller of the first formed angle and the second formed angle in the range where the first member and the second member relatively move is defined as the second formed angle. The telescopic device is a joint device provided such that a tensile force acts on the shaft member when the second formed angle increases.

11. The joint device according to any one of Claims 1 to 10, which is a prosthetic device in which the first member is mounted on the wearing body with respect to the second member so as to be on the end side of the wearing body.

12. The joint device according to Claim 11, wherein the prosthetic device is a prosthetic foot device mounted on the leg of the wearing body.

13. The joint device according to Claim 12, wherein the second member is mounted on the thigh of the leg, and the connecting portion is provided to function as a knee joint between the thigh and the lower leg.