JPH09551A - Free leg phase control method and air cylinder device for prosthetic foot - Google Patents

Abstract

PURPOSE: To provide a control technology capable of causing not only a reaction force but also a cushion force to have pertinent characteristics corresponding to a walking speed. CONSTITUTION: A double acting air cylinder device 10 capable of stroking, depending on bending and stretching of a knee, is used, and has a first flow passage 110 including a check 30 at sections of a piston 20 and a rod 40. Also, the device 10 has a second flow passage 210 including a variable throttle valve 50 at a section of a cylinder body 70. The valve 50 pertinently changes the opening thereof, depending on a walking speed. In addition, a cushion force against the stretching is generated with the valve 50 within the device 10, when the knee arrives at the prescribed stage before the complete stretch of the knee at a stretching process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for controlling the movement of a prosthesis involving flexion and extension of the knee, especially the movement of a thigh prosthesis. The present invention relates to a method for effectively obtaining a cushioning force in the final stage of knee extension.

[0002]

BACKGROUND OF THE INVENTION Natural gait is a dream for those who wear artificial legs. The natural gait is accompanied by flexion and extension of the knee and changes in walking speed. Therefore, when seeking a natural gait, a prosthesis accompanied by knee flexion and extension is desired. Prostheses that meet such demands, for example, thighs that have been amputated and for those without knees, are equipped with a cylinder device at the rear of the knee. The cylinder device has a reduction stroke in which the cylinder length is short when the knee is bent, and an extension stroke in which the cylinder length is long when the knee is extended. The cylinder device allows the knee to bend and extend, but the following functions are also important for natural walking. 1 Resistance force when the knee is bent: The resistance force allows the knee to be gently bent. 2 Repulsive force after maximum bending: The repulsive force gives an accelerating action of swinging the lower leg forward. 3 Cushion force at the final stage of extension: The cushion force or the deceleration action smoothes the ground contact and prevents strong contact between the thigh and the lower leg.

[0003]

[First Prior Art for Knee Flexion and Extension] The first prior art is the technology described in the official gazette of Japanese Patent Publication No. 52-47638. FIG. 10 shows an outline of the air cylinder device used therein. The air cylinder device 1010 has a check valve 1030 inside the piston 1020 and a needle valve 1050 inside the rod 1040. The needle valve 1050 fulfills the above-mentioned function 1 by giving flow resistance to the air flowing from the first chamber 1061 on the bottom side to the second chamber 1062 on the head side when the knee bends. Also, the check valve 1030 is
The air in the first chamber 1061 on the bottom side is compressed,
The above-mentioned function 2 will occur. Further, in the air cylinder device 1010, the rod large diameter portion 1 is attached to the rod 1040.
042, the inner hole 108 on the head side of the cylinder body 1070.
0, respectively, and in the final stage of knee extension, the rod large diameter portion 1042 enters into the inner hole 1080 and encloses air in the inner hole 1080. The contained air causes the above-mentioned function 3. In such first prior art, since the valve opening degree of the needle valve 1050 is adjusted from the outside, control corresponding to the walking speed cannot be performed.

[0004]

[Second Prior Art for Knee Flexion and Extension] The second prior art is the technology described in Japanese Unexamined Patent Publication No. 5-228168, and relates to the proposal of the present applicant. FIG.
1A shows the outline of the air cylinder device used therein. Also in the air cylinder device 2010, the piston 202
0, the check valve 2030, the needle valve 2050 in the rod 2040, and the rod large diameter portion 2042 of the inner hole 2080 of the cylinder body 2070 on the head side at the final stage of knee extension. The point of entering is the same as that of the first prior art. However, in the second prior art, the valve opening adjusting means 2300 including a motor and the like is provided at the end of the rod 2040, and the adjusting means 230 is provided.
With 0, the valve opening of the needle valve 2050 can be automatically adjusted according to the walking speed during walking. Further, in the second prior art, in addition to such a variable valve 2050, there is, so to speak, a fixed throttle 2090 similar to the fixed needle valve 1050 in the first prior art. The diaphragm 2090 is located in the head portion of the cylinder body 2070, and one opening is located in the middle of the flow path facing the inner hole 2080 and the other opening is facing the second chamber 2062 on the head side.
Accordingly, when the rod large diameter portion 2042 enters the inner hole 2080 in the final stage of knee extension, the chamber around the rod large diameter portion 2042 adjacent to the piston 2020 can function as a cushion chamber. Therefore, according to the second prior art, as shown in FIG. 11B, it is possible to obtain the repulsive force according to the walking speed by the variable needle valve 250, and also the fixed throttle 2
The cushioning force can be obtained by 90. Since this cushion force is fixed, it cannot take an appropriate value according to the walking speed. As a result, it can be seen that the difference between the repulsive force and the cushion force becomes larger and the impact when the knee is fully extended becomes larger, especially when the walking speed is higher (that is, when the valve opening degree is smaller).

[0005]

OBJECTS OF THE INVENTION The present invention has variously studied the above-mentioned prior art, and considered the technical problems found therein,
It is an object of the present invention to provide a technique capable of more effectively obtaining the above-mentioned three functions required for natural walking. In particular, the present invention has an object to provide a control technique capable of adjusting not only the repulsive force but also the cushion force to an appropriate characteristic according to the walking speed. Another object of the present invention is to provide an air cylinder device for a prosthesis, which has a repulsive force and a cushioning force according to a walking speed, but can make the prosthesis slim without increasing the size. To do.

[0006]

The control characteristics required by the invention are shown in FIG.
As shown in, the characteristic that not only the repulsive force but also the cushion force is changed according to the walking speed is realized. That is,
The greater the walking speed (that is, the smaller the valve opening), the greater the repulsive force is required. However, in the present invention, the cushioning force also has a characteristic curve d corresponding to the characteristic curve r of the repulsive force. To achieve. In order to enable continuous walking, it is necessary to set the repulsive force to be slightly larger than the cushion force at the same valve opening or walking speed. The difference between the repulsive force and the cushioning force varies depending on the person who wears the artificial leg. Therefore, it is preferable to provide the artificial leg with means for adjusting according to the individual difference. As a means therefor, it may be incorporated in a control unit for controlling the valve opening degree, or a mechanical adjusting mechanism may be provided for predefining the valve opening degree depending on the screwing degree of the screw. Although the characteristic curve of FIG. 1 is shown as a continuous curve, it may be a curve that changes stepwise.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention is premised on using a double-acting air cylinder device that strokes in response to bending and extension of the knee. The piston of the air cylinder device divides a bottom-side first chamber and a head-side second chamber inside a cylindrical cylinder body. The present invention is a technique for controlling a flow of air between the first chamber and the second chamber to bring the walking closer to a natural walk. In the present invention, the inside of the air cylinder device,
It has a basic feature in that a variable throttle valve that produces a resistance force to the bending of the knee is also used to obtain a cushioning force when the knee is extended. That is, in the present invention, after the variable throttle valve reaches a predetermined stage before the knee is completely extended during the extension stroke, a cushioning force is generated for the extension. FIG. 2 shows one of the preferred embodiments of the present invention, and shows an arrangement of a flow path and a valve that connect a first chamber 61 on the bottom side and a second chamber 62 on the head side. ing. 2A is the arrangement from the beginning of knee extension (that is, the state in which the knee is bent) to the predetermined stage of extension, and FIG. 2B is the arrangement at the predetermined stage before extension of the knee and complete extension. Is. As shown in FIG. 2, two first and second flow channels 110 and 210 are connected in parallel between the first chamber 61 and the second chamber 62. The first channel 110 includes the second chamber 62 to the first chamber 6
There is a check valve 30 that allows the flow towards 1. Further, the second flow path 210 has a variable throttle valve 50 whose valve opening can be adjusted according to the walking speed. Then, in the final stage of extension in which the knee is completely extended, the fixed throttle 90 is connected in series to the check valve 30 of the first flow path 110, as shown in FIG. 2B. .

As a means for adding the flow passage including the fixed throttle 90 in the final stage of extension, the additional flow passage including the fixed throttle 90 is connected to the first flow passage 110 according to the stroke of the piston. It is possible to apply a method of switching as follows. For example, as in the case of the above-mentioned prior art, it is possible to switch from the state A to the state B of FIG. 2 by allowing the large diameter portion of the rod to enter the inner hole on the head side of the cylinder body.

When the knee is extended, the air flows from the second chamber 62 on the head side to the first chamber 61 on the bottom side. In the present invention, the air is parallel between the second chamber 62 and the first chamber 61. Since there is the first flow channel 110 and the second flow channel 210,
The air flow is fast and the piston slides smoothly. Therefore, the motion of extending the knee is quick, and the above-described action of swinging out the lower leg can be effectively performed. At the final stage of extension, the variable throttle valve 50 and the fixed throttle 9
Both 0 and blunt the sliding of the piston, exerting a cushioning force on the extension of the knee. Therefore, sufficient cushioning force can be obtained. In this case, it is preferable to arrange a restrictor in the second flow path 210 in series with the variable throttle valve 50. The restrictor restricts the air flowing from the first chamber 61 to the second chamber 62, and restricts the air flowing from the second chamber 62 to the first chamber 62.
Only the flow of air that attempts to flow into the chamber 61 is restricted.
Therefore, when the valve opening is small, the restrictor produces a more appropriate cushioning force in the final stage of extension, in other words, a cushioning force more suited to the wearer of the artificial leg. Therefore, as a more simplified form, the fixed throttle 90 can be omitted by providing a restrictor. Further, when obtaining the cushioning force for such extension, it is preferable that the cushioning force by the variable throttle valve 50 is mainly used and the fixed throttle 90 adjusts the cushioning force so as to eliminate individual differences depending on the user of the artificial leg. . As a result, the same prosthesis can be applied to a large number of people with individual differences, the versatility of the prosthesis can be expanded, and the cost can be reduced.

Further, in order to slim the prosthesis itself accompanied by bending and extension of the knee, it is preferable that the rod side extending outward from the cylinder body is arranged above and the bottom side of the cylinder body is arranged below. To achieve such an arrangement, in the preferred embodiment of the present invention, the second flow path 21
0 is provided in the cylinder body, and the second flow passage 21
In the middle of 0, the variable throttle valve 50 is provided on the bottom side of the cylinder body.

[0011]

【Example】

(Application to Thigh Prosthesis) The present invention can be applied to a prosthesis involving flexion and extension of the knee, the representative of which is the thigh prosthesis. FIG. 3 is a diagram showing the overall configuration of the thigh prosthesis, and FIG. 4 is a detailed assembly diagram centering on the knee portion. The thigh artificial leg 500 includes a plastic socket 520 corresponding to the thigh, and an aluminum corresponding to the lower leg, which is rotatably supported by a lower end of the socket 520.
A frame 540 made of carbon fire or the like and a foot portion 560 supported at the lower end of the frame are provided. The thigh artificial leg 500 has the air cylinder device 10 for bending and extending the knee. The air cylinder device 10 includes an upper support point 550 near a support point 530 formed by pin connection between the socket 520 and the frame 540, and a lower support point 570 midway in the longitudinal direction of the frame 540. As a result, the air cylinder device 10 has a contraction stroke in which the cylinder length is small when the knee is bent, and an extension stroke in which the cylinder length is large when the knee is extended. here,
The cylinder length means the upper support point 5 of the air cylinder device 10.
The length between 50 and the lower support point 570. Focusing on each support point, the upper support point 550 is located at the rod head at the tip of the rod 40 extending out from the cylinder body 70, and the lower support point 570 is located at the trunnion pin on the bottom side of the cylinder body 70. Part of. In addition, a walking speed detection mechanism 580 including a proximity switch and a knee braking mechanism 590 arranged around the support point 530 are provided in the knee portion of the thigh artificial leg 500.

(First Embodiment) FIGS. 5 and 6 show an air cylinder device 10 of the first embodiment. FIG. 5 corresponds to a state when the knee is bent, and FIG. 6 corresponds to a state in the final stage of knee extension. To do. The air cylinder device 10 includes a cylindrical cylinder body 7 made of aluminum alloy or synthetic resin.
0 is provided. The cylinder body 70 includes a cylinder tube 72 having a uniform inner diameter, and covers 74 and 76 located at respective ends of the cylinder tube 72. The rod cover 74 through which the rod 40 penetrates has a small diameter hole 82 for guiding the rod 40 and an inner hole 80 having a diameter intermediate between the small diameter hole 82 and the inner diameter of the cylinder tube 72. In addition, the cover 76 on the bottom side of the cylinder body 70 has a thick portion 7
62, and the thick portion 762 is located at a position radially outward from the axial center of the cylinder tube 72. Then, there is a flow path (second flow path) 210 that starts from the thick portion 762, passes through the inside of the cylinder tube 72, and opens to the inner periphery near the rod cover 74. The thick portion 762 is a portion for incorporating the variable throttle valve 50, and the thick portion 762 is located at an eccentric position because the control unit 320 for controlling the valve is arranged.

The variable throttle valve 50 includes a poppet type valve body 52 made of stainless steel and a valve spring 54 for urging the valve body 52 in the valve opening direction. The valve body 52 receives the force of the valve spring 54, and the drive motor 34 that is a stepping motor.
It hits the end of a shaft 342 of zero. Drive motor 340
Is provided with a screw mechanism for converting a rotational movement into a rectilinear movement, and the screw mechanism moves the shaft 342 back and forth in the axial direction. Therefore, the shaft 342 of the drive motor 340 can move the valve body 52 back and forth, thereby adjusting the valve opening degree of the variable throttle valve 50. The control unit 320 includes an electronic unit including a semiconductor chip and the like, generates a control signal according to the walking speed, outputs the control signal to the drive motor 340, and appropriately adjusts the valve opening degree of the variable throttle valve 50.

On the other hand, the piston 20 made of synthetic resin is fitted in the cylinder tube 72 of the cylinder body 70 so as to be movable in the axial direction. Piston 20
A piston ring 22 is held on its outer circumference, thereby defining two chambers in front of and behind it. Thick part 7
The chamber on the bottom side having 62 is the first chamber 61, and the chamber on the rod cover 74 side is the second chamber 62. Here, it should be noted that when the piston 20 slides inside the cylinder tube 72, the piston 20 does not close the openings 211 and 212 at both ends of the second flow path 210. That is, the valve body 52 of the variable throttle valve 50
The opening 211 facing the bottom is formed by the ring-shaped projection 721 provided on the wall surface of the bottom portion of the cylinder body 70, and the opening 212 near the rod cover 74 is located on the tapered surface 722, so that It is open.

A piston rod 40 is integrated with the piston 20, and the rod 40 extends through the rod cover 74 and out of the cylinder body 70. The portion of the rod head 45 of the rod 40 located outside thereof corresponds to the upper support point 550 of the air cylinder device 10. The rod 40 has a rod large-diameter portion 42 adjacent to the piston 20, and the diameter of the large-diameter portion 42 is the rod cover 74.
The inner diameter of the inner hole 80 is substantially matched with the diameter of the inner hole 80. Moreover, lip-type seal rings 83 and 85 are provided at the opening of the inner hole 80 and the small-diameter hole 82, respectively. Therefore, as shown in FIG. 6, when the rod large diameter portion 42 enters the inner hole 80 in the final stage of knee extension, the third chamber 63 is defined in the inner hole 80.

Now, the piston 20 and the rod large diameter portion 4
Notice the second part. The end originates from one opening 111 on one surface of the piston 20, penetrates the piston 20 and the rod large diameter portion 4, and the other opening 112 of the small diameter portion of the rod 40.
There is a flow path (first flow path) 110 that reaches to (1). A check valve 30 is provided in the first flow path 110 along the way. The check valve 30 includes a ball valve element 32, a valve spring 34 that urges the ball valve element 32 toward a valve seat in a valve closing direction, and a valve spring 34.
And a support ring 36 for supporting the. Such a non-return valve 30 is provided with a second valve until the knee extension reaches the final stage.
Air is allowed to flow from the chamber 62 through the first flow path 110 to the first chamber 61 to smoothly extend the knee. Moreover, at the time of expansion, there is also the second flow path 210 connected in parallel to the first flow path 110, so that the air flow from the second chamber 62 to the first chamber 61 flows more smoothly. However, when the rod large-diameter portion 42 enters the inner hole 80 of the rod cover 74 so as to seal the inner hole 80 before the knee is completely extended, as shown in FIG. A third chamber 63 is defined in the hole 80, and a cushion chamber 65 is defined around the rod large diameter portion 42.

According to the present invention, the check valve 30 of the first flow passage 110 is provided at a predetermined stage before the knee is completely extended.
The fixed diaphragm 90 is configured to be connected in series. The fixed throttle 90 comprises a screw-in type needle valve, and the valve opening degree can be set according to the degree of screwing. Therefore, the fixed throttle 90 may be adjusted in advance and the valve opening may be set before using the artificial leg, taking into consideration individual differences. One opening 3 in the rod cover 74
12 communicates with the first channel 110 through the third chamber 63,
Moreover, the additional flow passage 310 in which the other opening 311 communicates with the second chamber 62 (that is, the cushion chamber 65).
And the fixed throttle 90 is arranged in the middle of the flow path 310. According to the air cylinder device 10, not only the other opening 311 of the additional flow passage 310 but also the opening 212 of the second flow passage 210 is opened to the cushion chamber 65. Therefore, the cushion based on the fixed throttle 90 is provided. Not only the action but also the cushion action based on the variable throttle valve 50 can be obtained.

(Second Embodiment) In the air cylinder device 710 shown in FIG. 7, the air cylinder device 1 in the first embodiment is used.
0 has been partially changed to further improve the cushioning characteristics. Air cylinder device 710 related to the second embodiment
A restrictor 400 is provided in the second flow path 210 in series with the variable throttle valve 50. A of FIG. 8 is a partial view showing an enlarged part of the restrictor 400. As can be seen from FIG. 8A, the restrictor 400 is
Mainly a cantilevered rubber plate 410, and the rubber plate 4
10 has a small through hole 420. Therefore, the restrictor 400, as shown in the equivalent circuit of FIG.
The throttle formed by the through hole 420 and the check valve formed by the rubber plate 410 (the check valve allowing the flow from the first chamber 61 to the second chamber 62) are connected in parallel to form a circuit. In other words, the restrictor 400 limits only the flow from the second chamber 62 to the first chamber 61. The restrictor 400 increases the cushioning force when the walking speed is high, and realizes a more ideal cushioning force characteristic.

(Third Embodiment) In an air cylinder device 910 shown in FIG. 9, first and second flow paths 110 and 210 are provided inside the piston 20 and the rod 40. Further, unlike the air cylinder devices 10 and 710 of the first and second embodiments, the controller unit 3
20 and motor 340 valve opening adjustment means 300
Is arranged at the outer end of the rod 40. However, the flow path configuration at the time when the knee extension reaches the final stage is the same as that of the second embodiment.

[Brief description of drawings]

FIG. 1 is a diagram showing control characteristics required by the present invention.

FIG. 2 is a diagram showing an arrangement of flow paths and valves.

FIG. 3 is a diagram showing the overall configuration of a femoral prosthesis.

FIG. 4 is a detailed assembly diagram centering on a knee portion.

FIG. 5 is a cross-sectional view showing a first embodiment of the air cylinder device, showing a state when the knee is bent.

FIG. 6 is a sectional view showing another state of the first embodiment of FIG.

FIG. 7 is a sectional view showing a second embodiment of the air cylinder device.

8 is a diagram for explaining a restrictor portion of the second embodiment of FIG. 7. FIG.

FIG. 9 is a sectional view showing a third embodiment of the air cylinder device.

FIG. 10 is a diagram for explaining the first prior art.

FIG. 11 is a diagram for explaining the second prior art.

[Explanation of symbols]

 10, 710, 910 Air cylinder device 20 Piston 30 Check valve 40 Rod 42 Rod large diameter part 50 Variable throttle valve 61 First chamber 62 Second chamber 63 Third chamber 65 Cushion chamber 70 Cylinder body 80 Inner hole 90 Fixed throttle 110 First flow path 210 Second flow path 310 Additional flow path 400 Restrictor 500 Femoral prosthesis

 ─────────────────────────────────────────────────── (72) Inventor Shigeki Nakatani 3-13 Mizutani, Tamazu-cho, Nishi-ku, Kobe-shi, Hyogo Prefecture (72) Kazuo Wakabayashi 1-4-2 Nishitachidachi-dori, Hyogo-ku, Kobe-shi, Hyogo Prefecture

Claims (15)

[Claims] 1. A cylinder device, which is located at a rear portion of a knee, has a reduction stroke in which the cylinder length is small when the knee is bent, and has an extension stroke in which the cylinder length is increased when the knee is extended, and further, the cylinder device is provided. Is equipped with a variable throttle valve that changes according to the walking speed, and in the swing phase control method of the artificial leg that controls knee bending and extension by this variable throttle valve, the knee is completely extended by the variable throttle valve. A method for controlling a swing phase, wherein a cushioning force against extension is generated when a predetermined position before reaching is reached 2. The cylinder device comprises a cylindrical cylinder body, a piston inside the cylinder body, which partitions the cylinder body into a bottom-side first chamber and a head-side second chamber, and one end A rod that is integral with the piston and has the other end extending to the outside from the head side of the cylinder body, and has first and second flow paths that connect the first chamber and the second chamber, From the second chamber to the first channel
2. The swing phase control method according to claim 1, wherein there is a check valve that allows a flow toward the chamber, and there is the variable throttle valve in the second flow path. 3. A cylinder device, which is located at the rear part of the knee, has a reduction stroke in which the cylinder length is small when the knee is bent, and has an extension stroke in which the cylinder length is increased when the knee is extended. A cylindrical cylinder body, and a piston inside the cylinder body for partitioning the cylinder body into a bottom-side first chamber and a head-side second chamber;
One end is integrated with the piston, and the other end side is provided with a rod extending from the head side of the cylinder body to the outside,
There are first and second flow paths that connect the first and second chambers, and the first flow path includes a check valve that allows a flow from the second chamber to the first chamber, and the first flow path. A variable throttle valve is provided in each of the two flow paths, and the check valve and the variable throttle valve are used to control the movement of the artificial leg in the swing phase, wherein the first and second flow paths are parallel. Yes, the variable throttle valve can adjust the valve opening according to the walking speed,
Further, the cylinder device is configured such that a fixed throttle is connected in series to the check valve of the first flow path at a predetermined stage before the knee is completely extended during the extension stroke. At the time of bending, the variable throttle valve generates a resistance force against bending, and when the knee is extended, the first and second flow paths connected in parallel enable the smooth extension. A method for controlling a free-leg phase in a prosthesis, wherein a cushion force for extension is generated by the variable throttle valve and the fixed throttle after reaching the predetermined stage. 4. The cylinder device includes a control section for generating a control signal according to a walking speed for adjusting the valve opening of the variable throttle valve, and a motor driven according to the control signal from the control section. The swing phase control method according to claim 1, further comprising: 5. The prosthesis comprises a socket corresponding to a thigh, a frame rotatably supported by a lower end of the socket and corresponding to a lower leg, and a foot supported by a lower end of the frame. 5. The free leg phase control according to claim 1, further comprising a thigh artificial leg, wherein the cylinder device includes an upper support point near a support point between the socket and the frame and a lower support point in a middle of a longitudinal direction of the frame. Method. 6. The idle phase control method according to claim 3, wherein the fixed throttle comprises a screw-in type needle valve, and the valve opening is set according to the degree of screwing. 7. A restrictor is connected in series to the variable throttle valve in the second flow path, and the restrictor is the second restrictor.
The swing phase control method according to claim 2 or 3, wherein only the flow from the chamber to the first chamber is restricted. 8. The cylinder body of the cylinder device has an inner hole having a diameter smaller than the inner diameter of the other portion of the cylinder body on the head side thereof, and the rod has a rod portion at a portion adjacent to the piston. Larger diameter than other parts,
Moreover, at the time of the extension stroke, a large-diameter portion is inserted into the inner hole so as to seal the inner hole, and the time when the large-diameter portion is inserted into the inner hole so as to seal the inner hole is the knee. 4. The swing phase control method according to claim 2 or 3, which is a predetermined step before completely extending. 9. When obtaining the cushioning force for the extension, the cushioning force by the variable throttle valve is mainly used, and the cushioning force is adjusted by the fixed throttle so as to eliminate the individual difference depending on the user of the artificial leg. The swing phase control method according to claim 3. 10. An air cylinder device for a prosthesis that responds to bending and extension of a knee, comprising a cylindrical cylinder body, and inside the cylinder body, the cylinder body is provided in a bottom-side first chamber and a head-side chamber. A piston that is divided into the second chamber, one end that is integral with the piston, and the other end that extends outward from the head side of the cylinder body, and a rod that is located in a portion of the rod that is adjacent to the piston. In the final stage of extension, a rod large diameter portion that fits into the inner hole on the head side of the cylinder body and defines the third chamber inside the inner hole, and a flow passage that penetrates the rod large diameter portion and the piston, When the rod large-diameter portion separates the third chamber from the first flow path, which has a check valve that allows a flow from the second chamber to the first chamber, on the way, one opening is the third chamber. Through the first flow path Further, the other opening is a flow path that connects to the second chamber, and an additional flow path having a fixed throttle in the middle and the first chamber and the second chamber are connected to each other. In the air cylinder device for a prosthesis, the flow channel includes a second flow channel in the middle of which a variable throttle valve whose valve opening can be adjusted according to a walking speed of a person wearing the prosthesis is provided. An air cylinder device for a prosthesis, characterized in that the second flow passage is in the cylinder body, and the variable throttle valve is on the bottom side of the cylinder body in the middle of the second flow passage. 11. The prosthesis comprises a socket corresponding to a thigh, a rotatably supported lower end of the socket, a frame corresponding to a lower leg, and a foot supported at a lower end of the frame. The cylinder device includes an upper support point near the support point between the socket and the frame, and a lower support point in the middle of the longitudinal direction of the frame, and extends outward from the head portion of the cylinder body. The artificial air cylinder device according to claim 10, wherein the upper support point is located at the end of the rod, and the lower support point is located on the bottom side of the cylinder body. 12. The variable throttle valve extends in the same direction as the axis of the cylinder body, and the axis of the variable throttle valve is located at a position radially offset from the axis of the cylinder body. 10. Air cylinder device for prosthesis. 13. The artificial air cylinder device according to claim 10, wherein the fixed throttle comprises a screw-in type needle valve, and the valve opening is set according to the degree of screwing. 14. The restrictor is connected in series to the variable throttle valve in the second flow path, and the restrictor restricts only a flow from the second chamber to the first chamber.
Zero artificial air cylinder device. 15. The variable throttle valve includes a valve body and a valve spring for urging the valve body in a valve opening direction, and a control according to the walking speed for adjusting the valve opening degree. The motor includes a control unit that generates a signal and a motor that is driven in response to a control signal from the control unit. Further, the motor has a shaft that moves back and forth in the axial direction by a screw mechanism, and the shaft has the shaft. The air cylinder device for a prosthesis according to claim 10, which supports the valve body.