The present invention relates to a knee joint for use in prosthetic.
BACKGROUND
[0002]
　In general, prosthetic is constituted by a socket fixed to the cut surface of the foot, the knee joint is connected to the lower end of the socket, the foot portion to which the connection has been grounded portion at the lower end of the knee joint. Knee joint, like a knee joint, so that it is extended and bent in a predetermined angle range.
[0003]
　The driving method of the knee joint, and passive, and electronically controlled, three types of active type exists. The passive, wearer moves the prosthesis, in response to movement of the prosthesis, by using a damper and a spring force of the hydraulic or pneumatic cylinder, passively knee joint is adapted to flexion / extension. In electronically controlled, the movement resistance in the bending and stretching of the knee joint is adjusted by the electronic control, and to be able to improve the operation of the knee joint. It shows an example of a knee joint of the electronically controlled in Patent Document 1. Further, in the active type, by controlling the bending angle of actively knee joint using a motor, so as to assist the movement of the knee joint in the operation of such climbing stairs or rising.
[0004]
　By the way, the knee joint of the conventional active formula, the structure is not only expensive due to the complexity of the wearer there is a problem that is easy to fatigue in for heavy. In particular, the knee joint of a conventional active type, it is necessary to constantly operate the motor mounted on the knee joint, the energy efficiency is poor, requiring a large battery capacity, there is a large and heavy tend.
[0005]
　On the other hand, Non-patent Document 1, to convert the linear motion by the series elastic actuator (so-called "Series Elastic Actuator") into rotational motion by the pulley, the active expression of the knee joint to rotate the knee joint is shown . In this technique, by using a spring of the series elastic actuator it leverages walking energy, compared to the energy efficiency of conventional active-type knee joint, to obtain a high energy efficiency. However, in this technique, to convert the linear motion of the series elastic actuator into rotational motion of the knee, the belt that is fixed to the elastic element to linear motion via the two pulleys, so the mechanism for rotating the knee there. To prevent interference with the linear elastic elements and knees, it is necessary to arrange the belt and the pulley on the side surface of the knee joint. Then, in order to maintain balance, there arises a need to use two belts in one knee joint. Thus, in this technology, mechanism becomes very complicated, there is a problem in that a large number of parts. When Grow the movable angle of the knee joint (movable range), a belt and a pulley is increased in size, it becomes those difficult to use in terms of size and weight. Further, a belt for rotating the pulleys, because there is a problem in durability, there is a tendency that the cost tends to be high for its maintenance and replacement.
[0006]
　Further, the following Patent Document 2, the knee member rotatably attached to the upper end of the leg member, configured for attaching the foot member to the lower end of the leg member is described. Protrusions on the side of the knee member is integrally formed, the linear actuator is mounted between the bottom of the projecting portion and the leg member. In this technique, the driving force of the linear actuator, so that the can assist the rotation of the knee member. However, in this technique, since the linear actuator is directly connected structure without gears in the knee member, when trying to obtain a high drive torque, there is a problem that a high load on the linear actuator it takes.
CITATION
Patent Document
[0007]
Patent Document 1: JP 2004-167106 Patent Publication
Patent Document 2: International Publication 2004/017872 Patent Laid
Non-patent literature
[0008]
非特許文献1 : Elliott J. Rouse, Luke M.Mooney and Hugh M. Herr, "Clutchable series-elastic actuator: Implications for prosthetic knee design" October 9, 2014, doi: 10.1177/0278364914545673 The International Journal of Robotics Research November 2014 vol. 33 no. 13 1611-1625
Summary of the Invention
Problems that the Invention is to Solve
[0009]
　The present invention was made based on the above-described situation. The main purpose of the present invention, energy efficient, a small and light, yet, is to provide a knee joint capable of wider movable range.
Means for Solving the Problems
[0010]
　Means for solving the problems described above can be described as the following items.
[0011]
　(Item 1)
　and a driving unit, in series elastic mechanism includes a crank mechanism,
　the series elastic mechanism includes a driven member, and the elastic member, and a linear motion member,
　the driving unit, the has a structure for moving the driven member,
　said elastic member, said is disposed between the driven member and the linear motion member,
　said linear motion member via the elastic member, the driven member in accordance with the movement, and is configured to move in at least one direction resiliently,
　the crank mechanism is configured and going on the knee joint into a rotary motion to linear motion of the linear motion member.
[0012]
　(Item 2)
　further comprises an upper connecting portion for connecting the socket and the knee joint,
　the crank mechanism is configured for rotational movement the upper connecting portion in forward and reverse directions
　according to Item 1 knee joint.
[0013]
　(Item 3)
　comprises a further frame,
　the linear motion member is movable along at least one direction relative to the frame
　knee joint of claim 1 or 2.
[0014]
　(Item 4)
　further comprises a frame,
　the rotation axis of the crank mechanism is supported by the frame
　knee joint of claim 1 or 2.
[0015]
　(Item 5)
　The drive unit includes a motor, a transmission mechanism comprises a ball screw,
　said motor through said transmission mechanism has a structure that rotates the ball screw in forward and reverse directions ,
　the driven member, said has a configuration for linear motion in response to rotation of the ball screw
　knee joint according to any one of claims 1-4.
[0016]
　(Item 6)
　The linear motion member, said comprises a first abutment portion being arranged to face the second contact portion across the driven member,
　said elastic member, first spring and the second and a spring,
　the first spring, the is disposed between the first the driven member and the contact portion,
　the second spring, and the driven member and the second contact portion It is disposed between
　the knee joint according to any one of claims 1-5.
[0017]
　(Item 7)
　artificial leg comprising a knee joint according to item 1 or item 1-6.
Effect of the invention
[0018]
　According to the present invention, energy efficient, it is possible to provide a knee joint capable of wider compact and lightweight and the movable range. Further, according to the present invention, it is possible to provide an inexpensive knee joint relatively yet active.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
[Figure 1] of the knee joint in one embodiment of the present invention (flexion angle = 0 °), is a perspective view of a state where excluding the cover was.
It is a front view of FIG. 1; FIG.
It is a left side view of FIG. 3 FIG.
Is a plan view of FIG. 4 FIG.
Is a sectional view taken along FIG. 5] A-A line in FIG.
[6] of the knee joint of FIG. 1 is a perspective view of a state in which the cover attached.
It is a front view of FIG 7 FIG. 6.
It is a left side view of FIG. 8 Fig.
Is a plan view of FIG. 9 Fig.
It is a sectional view taken along the line A-A of FIG. 10 FIG.
[11] of the knee joint of FIG. 1 is a perspective view of a state of flexion 60 °.
It is a front view of FIG. 12 FIG. 11.
It is a left side view of FIG. 13 FIG. 12.
Is a plan view of FIG. 14 FIG. 12.
Is a sectional view taken along FIG. 15] A-A line in FIG. 13.
[Figure 16] Figure 1 of the knee joint is a perspective view of a state of flexion 120 °.
It is a front view of FIG. 17 FIG. 16.
It is a left side view of FIG. 18 FIG. 17.
Is a plan view of FIG. 19 FIG. 17.
Is a sectional view taken along FIG. 20] A-A line in FIG. 18.
[Figure 21] shows an example in which the prosthesis with the knee joint of FIG. 1 is a schematic illustration.
FIG. 22 is an explanatory diagram for explaining the operation of the prosthesis of Figure 21.
It is an explanatory diagram for explaining the operation of the crank mechanism in the knee joint of FIG. 23 FIG.
It is a schematic illustration of a crank mechanism of FIG 24 FIG 23.
[Figure 25] A graph showing an example of a characteristic of the crank mechanism of Fig. 24, the horizontal axis represents the knee angle (degrees), the vertical axis represents the reduction ratio.
A graph showing the change in knee angle during [26] walking, the horizontal axis represents time (arbitrary unit), and the vertical axis indicates the knee angle (degrees).
FIG. 27 is an explanatory diagram showing an example of changing the offset amount of the series elastic mechanism relative to the axis of rotation of the crank mechanism.
A characteristic example of a crank mechanism of FIG. 28 FIG. 27, a graph showing superimposed a characteristic example of FIG. 25, the horizontal axis represents the knee angle (degrees), the vertical axis represents the reduction ratio.
DESCRIPTION OF THE INVENTION
[0020]
　Hereinafter, a knee joint according to an embodiment of the present invention will be described with reference to the accompanying drawings (FIGS. 1 to 10). Among these figures, Figures 1 to 5 show a state that excludes the cover 51 of the frame 5 (described below), 6 to 10 shows a state of attaching the cover 51.
[0021]
　Knee joint 100 of the present embodiment, as shown in FIG. 21 (described later), in combination with the socket 200 and the foot 300, and to be able to configure the prosthesis. The following describes the structure of the knee joint 100 of the present embodiment.
[0022]
　(Configuration of the present embodiment)
　knee joint 100 of this embodiment includes a driving unit 1, a series elastic mechanism 2, and a crank mechanism 3. Furthermore, the knee joint 100 includes an upper connecting portion 4, a frame 5, and a lower connecting portion 6.
[0023]
　(Driver)
　driving unit 1 includes a motor 11, a transmission mechanism 12, a ball screw 13 (see FIG. 5). Motor 11 via the speed change mechanism 12 has a configuration which rotates the ball screw 13 in forward and reverse directions. Drive 1 of the present embodiment includes a battery (not shown), so as to drive the motor 11 by the power supply from the battery. However, it is also possible to adopt a configuration for driving the motor 11 by the external power supply (e.g., commercial power supply). The drive unit 1 is provided with a sensor (not shown) for detecting the load on the rotation angle and the motor 11 of the crank mechanism 3, it can control the torque and rotational speed of the motor 11 in accordance with the output of the sensor It has become way. Motor 11 of the present embodiment, the transmission mechanism 12 and the ball screw 13, is a frame 5 is supported via an appropriate attaching member or bearing.
[0024]
　(Series elastic mechanism)
　series elastic mechanism 2 includes a driven member 21, an elastic member 22, and a linear motion member 23. Also, the series elastic mechanism 2 of this embodiment includes a driven member 21, a guide shaft 24 for guiding the first and second contact portions 231, 232 of the linear motion member 23.
[0025]
　Driven member 21 by the driving force of the drive unit 1 along the guide shaft 24 (in the vertical direction in FIG. 1) has a configuration to be moved. More specifically, the driven member 21 of the series elastic mechanism 2 in the present embodiment, in accordance with the rotation of the drive unit 1 of the ball screw 13 are configured to reciprocate in a linear direction.
[0026]
　The elastic member 22 is disposed between the driven member 21 and the linear motion member 23. More specifically, the elastic member 22 of this embodiment includes a first spring 221 of the two and the second spring 222 of the two (see FIGS. 1 and 3). The first spring 221 has been arranged between the first contact portion 231 of the linearly moving member 23 (described later) and the driven member 21 is in the state not fixed to these members. The second spring 222, are disposed between the second contact portion 232 (described later) and the driven member 21 of the linear motion member 23 is in the state not fixed to these members.
[0027]
　Linear motion member 23 via the elastic member 22, in accordance with the movement of the driven member 21 are configured to move in at least one direction elastically. More specifically, as described above, linear motion member 23 of this embodiment includes a first contact portion 231 disposed on opposite sides of the driven member 21 and the second contact portion 232 and the direct acting rod and a 233. Further, the first contact portion 231 and the second contact portion 232 are connected by struts 234 (see FIG. 3). Strut 234 extends through the driven member 21, relative movement therebetween is enabled. Further, it struts 234 are arranged in a state of passing through the inside of the first spring 221 and second spring 222 of the elastic member 22, respectively. In this example, the lower end of the linear rod 233 and the upper end of the post 234 are coupled, they are integrated parts.
[0028]
　The guide shaft 24 is a two in the present embodiment, respectively, are arranged to connect the upper base 52 and the lower base 53 of the frame 5 (described later). (See Figure 2). Two guide shafts 24 is not fixed to the driven member 21 and the first contact portion 231 and the second contact portion 233, thereby, the driven member 21 and the first contact portion 231 second the contact portion 233, (in the vertical direction in other words 2) along the extending direction of the guide shaft 24 and is adapted to be movable.
[0029]
　Linear rod 233 of the linear motion member 23, in this embodiment, through the upper base 52 of the frame 5, is fixed to the upper surface of the first contact portion 231 (see FIGS. 2 and 3), in accordance with the movement of the first contact portion 231 and the second contact portion 232, (in the vertical direction in other words 1) along the extending direction of the guide shaft 24 is adapted to reciprocate.
[0030]
　(Crank mechanism)
　crank mechanism 3 is configured to convert the rotational motion of the linear motion of the linear motion member 23. Crank mechanism 3 of the present embodiment is provided with a connecting rod 31 and the arm member 32 and the rotary shaft 33.
[0031]
　One end of the connecting rod 31, the upper end of the linear motion rod 233 of the linear motion member 23 is pin-connected so as to be rotatable to each other.
[0032]
　The arm member 32, the other end of the connecting rod 31 is pin-connected so as to be rotatable to each other. The arm member 32 is swingable about an axis of rotation 33. At the top of the arm member 32, the upper connecting portion 4 is attached.
[0033]
　Rotary shaft 33, in this embodiment, is attached to the cover 51 (described later) of the frame 5, the relative position between the rotary shaft 33 and the frame 5 is fixed.
[0034]
　(Upper connecting portion)
　upper connecting portion 4 is for connecting the socket 200 (see FIG. 21 described later) and the knee joint 100. Upper connection portion 4, the crank mechanism 3, by rotary motion in the forward and reverse directions, realizing the operation of the extension-flexion of the prosthetic foot. Upper connection portion 4, also known as pyramid connector, which is to be connected to the socket 200 by using an existing method.
[0035]
　(Frames)
　Frame 5 of the present embodiment includes a cover 51 (see FIGS. 6 to 10), an upper base 52, and a lower base 53. In the present embodiment, the linear motion member 23, at least in one direction with respect to the upper and lower base 52, 53 of the frame 5 (specifically the vertical direction in FIG. 1) is made movable. In the present embodiment, as described above, the rotation shaft 33 of the crank mechanism 3, the cover 51 of the frame 5 is supported in a rotatable state. Upper base 52 and the lower base 53 further respectively have been secured to the cover 51, so as not to relatively move.
[0036]
　(Lower connecting portion)
　lower connecting portion 6 is for connecting the knee joint 100 and the foot 300 (see FIG. 21 described later). Lower connection portion 6 is fixed to the lower base 53 of the frame 5. Lower connecting portion 6 also, also known as pyramid connector, which is to be connected with the foot portion 300 by using an existing method.
[0037]
　(Operation of the Embodiment)
　Next, with further reference to FIGS. 11 to 22, the operation of the knee joint 100 of the present embodiment.
[0038]
　(60 ° from the angle adjusting operation ... 0 ° knee joint)
　in the description of this embodiment, the extended state shown in FIG. 1, the angle of the knee joint is defined as a 0 °. Explaining this state the operation for bending the angle of the knee joint in 60 ° below.
[0039]
　First, the motor 11 is rotated in the drive unit 1. Then, the ball screw 13 is rotated through the transmission mechanism 12, the driven member 21 of the series elastic mechanism 2 in one direction (in this example downward direction in FIG. 1) moves in.
[0040]
　Then, the driven member 21, for applying a compression force to the second spring 222 of the elastic member 22, through which the spring (in this example, the downward direction in FIG. 1) of the linear motion member 23 in one direction is moved to. When lowered by the linear motion member 23 spring force, the connecting rod 31 of the crank mechanism 3 is lowered, as a result, the arm member 32 rotates about the rotation shaft 33 (see FIGS. 11 to 15). Thus, it is possible to rotate the upper connecting portion 4 by a desired angle. Angle of the knee in human gait is repeated from 0 ° (an extended state) to about 60 ° (flexion). Therefore, after the knee flexion 60 °, by reversely rotating the motor 11, by applying a compressive force to the first spring 221, back to the extended state of 0 °.
[0041]
　(The angle adjustment operation of the knee joint ... 60 ° ~ 120 °)
　operation between the angle 60 ° of knee to 120 °, the sitting is user sit or, operation when the knee or arrived on the floor it is. When sitting is especially motor does not operate, when rising from a state sitting can assist by operation of the motor.
[0042]
　An example in which bending the knee joint to more than 60 ° is shown in FIGS. 16 to 20. By further rotating the arm member 32 of the crank mechanism 3 in the same manner as above, the knee joint up to about 120 ° (to ideally about 140 °) can be bent.
[0043]
　By reversely rotating the motor 11 of the drive unit 1, it is possible to return the flexion angle of the knee joint to the initial state (angle = 0 °).
[0044]
　In the present embodiment, the torque of the motor 11, by appropriately controlling the rotational speed or rotation angle, it is possible to dynamically change the bending angle of the knee joint 100. Prosthesis usage, for example, when rising from ranks or when a chair, by actively controlling the rotation angle of the knee joint by the driving force of the driving unit 1, the behavior of the prosthesis user (walking or alternately climbing stairs a and rising operation) can be supported.
[0045]
　In the technique described in Non-Patent Document 1 mentioned above, it has the following problems.
- a mechanism for converting the linear motion of the elastic mechanism into a rotational movement of the knee is very complicated, the number of components is large. Therefore, heavy made;
when you widen the movable angle of the knee joint, the pulley is enlarged;
to prevent interference between-component (elastic element) and the knee, it is necessary to arrange the pulleys on the side surface of the prosthesis . Then, to balance the two pulleys mechanism in a single prosthesis (one pulley mechanism the two pulleys and composed of a single connection cable and associated components) it is necessary to use;
cables for pulley is, there is a problem in terms of durability, maintenance cost is likely to be high.
[0046]
　In contrast, according to the knee joint of the present embodiment described above,
because of the use of crank mechanism, even when the spread of the movable angle of the knee joint, can suppress an increase in the size of the entire knee joint;
pulley mechanism instead of, it is possible to use small and light one crank mechanism, small size and lightweight prosthesis can provide;
crank mechanism, because generally has high durability as compared with the pulleys, reduce the maintenance costs it can
be able to demonstrate the advantage.
[0047]
　(Mounted state of the knee joint)
　Next, with reference to FIG. 21, an example was worn by the user the knee joint of the present embodiment. In this example, are connected to the lower end of the socket 200 in the upper connecting portion 4 of the knee joint 100, the foot portion 300 is connected to the lower connecting portion 6 of the knee joint 100. In the illustrated example, the knee joint 100 and the socket 200 and foot portion 300, the prosthetic foot is constructed. The connection between the upper connection section 4 and the socket 200, and, for connection with the lower connecting portion 6 and the foot portion 300 can be used similar to the conventional attachment (not shown).
[0048]
　(Walking with prosthesis)
　Next, with further reference to FIG. 22, illustrating a walking operation using the prosthetic foot of the present embodiment. Incidentally, in this figure, a reference numeral L in the prosthesis.
[0049]
　(FIG. 22 (a) ~ (b) )
　when the foot of the prosthetic foot lands on the floor, the knee joint of the present embodiment, push from the socket 200, via a crank mechanism 3, the downward linear motion member 23 pressure is applied, whereby the first spring 221 of the elastic member 22 is elastically deformed, its energy is accumulated. However, the linear motion member 23, since through the driven member 21 is attached to the ball screw 13, by operating the motor in reverse to the direction in which the ball screw to rotate, resistance to movement of the driven member 21 You can make a force to hold the energy in the elastic member 22.
[0050]
　In the present embodiment, by appropriately setting the spring force and the initial position of the elastic member 22, the bending angle (passive knee joint of the ground point of the foot (Fig. 22 (a) ~ (b)) the bending angle) due to deformation can be set to approximately 20 °. In this way, the human nature, the time of heel strike can achieve knee flexion angle of approximately 20 ° for shock absorption, there is an advantage that it is possible to improve the sense of use of the user.
[0051]
　Further, in the present embodiment, the repulsive force from the floor surface which joined the foot, so will be transmitted to the user via the elastic member 22, it is possible to alleviate the impact at the time of installation, the user it is possible to reduce the fatigue progress.
[0052]
　(FIG. 22 (b) ~ (d) )
　during the subsequent walking, the stored energy is released to the elastic member 22. Thus, by moving the linear motion member 23, it is possible to extend the knee joint.
[0053]
　(FIG. 22 (d) ~ (e))
　Thereafter, in the present embodiment, by operating the motor 11, (see e.g., FIG. 12) for bending the knee joint. This makes it possible to store energy in the elastic member 22.
[0054]
　(FIG. 22 (e) ~ (f) )
　Further when walking has progressed, in the present embodiment, by driving the motor 11 in the reverse direction, thereby stretching the knee joint. In the present embodiment, the energy accumulated in the elastic member 22, so assisting the stretching motion of the knee joint, it is possible to reduce the power required to the motor 11. Therefore, in the present embodiment, it is possible to expect a reduction in size and battery long-lasting battery.
[0055]
　Further, in the case of setting the frictional resistance low between the ball screw 13 and the linear motion member 23, by using the elastic force of the elastic member 22 described above, there is an advantage that power can be regenerated by the motor 11.
[0056]
　Next, the operation of the crank mechanism 3 of the present embodiment, further described in detail with reference to FIGS. 23 to 28.
[0057]
　First, for explaining the operation, the structure of the knee joint of the above-described embodiment, shown schematically in Figure 23. This figure shows the motor 11 and the transmission mechanism 12 and the elastic member 22 as a single actuator. Further schematically shown in FIG. 24 the mechanism of Figure 23.
[0058]
　Reduction ratio at the knee joint using the crank mechanism 3 is represented by the following formula.
[0059]

[0060]
　Here
N m : number of teeth of the motor 11 side in the speed change mechanism 12
pulley; N b : number of teeth of the ball screw 13 side in the speed change mechanism 12
pulley; L b : lead of the ball screw 13;
R: the arm member 32 turning radius;
K: deceleration coefficient due crank mechanism
is.
[0061]
　Here, each variable other than K, so can be regarded as constant in the description herein, a detailed description thereof will be omitted. Deceleration variable K of the crank mechanism can be expressed as follows.
[0062]

[0063]
　Here,
alpha: the arm member 32, the angle (in FIG. 24 vertical) longitudinal relative;
beta: a connecting rod 31, the angle with respect to (vertical direction in FIG. 24) the longitudinal direction
is.
[0064]
　The slowdown variable K, the reduction ratio in the crank mechanism is as shown in Figure 25. This property, the reduction ratio in accordance with the change of the knee angle and is changed, and has a reduction ratio up to the vicinity of the knee angle alpha = 80 °. That is, the crank mechanism of the present embodiment, with the change of the knee angle can drive the knee joint at different reduction ratio.
[0065]
　An example of a time course of knee angle due to human walking illustrated in Figure 26. As shown in this figure, while walking, knee angle varies between approximately 0 ° ~ 80 °. Further, for example, in the rise of the upstream and downstream and chairs stairs, there may be a knee angle changes once greatly from knee angle near about 80 ° to 0 ° nearby. If such a large angle change from deep knee angle is required to rotate the knee joint, a large torque is required. In the present embodiment, the deep knee angle of approximately 80 ° before and after, it is possible to obtain a high reduction ratio. Then, without imposing a heavy burden on the motor 11, there is an advantage that can provide a large torque to the knee joint.
[0066]
　Further, when the quick pace, the knee joint, while the sought fast rotational speed at flat knee angle, high torque is not required. The crank mechanism of the present embodiment, in the case of shallow knee angle (e.g. 0 ° ~ 20 °), since the low reduction ratio, there is an advantage that it is easy to increase the rotational speed of the knee joint.
[0067]
　If, in the case of using a pulley mechanism in place of the crank mechanism (see Non-Patent Document 1 mentioned above), since the pulley mechanism is absent deceleration coefficient K, the reduction ratio in the pulley mechanism includes a constant irrespective of the knee angle Become. Therefore, if a large torque is required, which may cause a great burden to the motor. Also in case of not using the transmission mechanism (see Patent Document 2 mentioned above), resulting in similar problems. In contrast, in the knee joint of the present embodiment, by using a crank mechanism, there is an advantage that it is possible to achieve both high torque and high speed rotation.
[0068]
　An example of changing the offset amount between the rotation center and the series elastic mechanism 2 of the crank mechanism 3 shown in Figure 27. The characteristics of the speed reduction ratio after the offset amount changes indicated by the solid line in FIG. 28. One-dot chain line in FIG. 28 is a characteristic in the example of FIG. 25. As can be seen from this figure, by changing the offset amount, it is possible to adjust the relationship between knee angle α and the speed reduction ratio. Therefore, according to this embodiment, there by adjusting the offset amount, an advantage that it is possible to obtain a maximum torque at the knee angle required.
[0069]
　The contents of the present invention is not limited to the embodiment. The present invention, within the scope described in the claims, is intended to be modified variously with respect to a specific configuration.
DESCRIPTION OF SYMBOLS
[0070]
　1 driver
　11 the motor
　12 the speed change mechanism
　13 ball screw
　2 series elastic mechanism
　21 driven member
　22 elastic member
　221 first spring
　222 second spring
　23 linearly moving member
　first contact portion 231
　232 second contact portion
　233 direct acting rod
　24 Guide shafts
　3 crank mechanism
　31 connecting rod
　32 the arm member
　33 rotates shaft
　4 the upper connecting portion
　5 frame
　51 cover
　52 upper base
　53 lower base
　6 lower connection part
　100 the knee joint
　200 socket
　300 feet unit
　L prosthesis

WE claims

[Requested item 1]
　A driving unit, in series elastic mechanism includes a crank mechanism,
　the series elastic mechanism includes a driven member, and the elastic member comprises a linear member,
　moving the driving part, the driven member has a configuration in which,
　the elastic member, the is disposed between the driven member and the linear motion member,
　said linear motion member via the elastic member, according to the movement of the driven member, at least way has a resiliently moving configuration,
　the crank mechanism is configured and going on to convert the rotary motion of the linear motion of the linear motion member
　knee joint.
[Requested item 2]
　Further comprises an upper connecting portion for connecting the socket and the knee joint,
　the crank mechanism is configured for rotational movement the upper connecting portion in forward and reverse directions
　the knee joint according to claim 1 .
[Requested item 3]
　Further comprises a frame,
　the linear motion member is movable along at least one direction relative to the frame
　knee joint according to claim 1 or 2.
[Requested item 4]
　Further comprises a frame,
　the rotation axis of the crank mechanism is supported by the frame
　knee joint according to claim 1 or 2.
[Requested item 5]
　The driving unit includes a motor, a transmission mechanism comprises a ball screw,
　said motor through said transmission mechanism has a structure that rotates the ball screw in forward and reverse directions,
　the driven member It is configured to linear motion in response to rotation of the ball screw
　knee joint according to any one of claims 1-4.
[Requested item 6]
　The linear motion member, said comprises a first abutment portion being arranged to face the second contact portion across the driven member,
　said elastic member includes a first spring and a second spring and,
　said first spring, said first is disposed between the contact portion and the driven member,
　said second spring is disposed between the driven member and the second contact portion and that
　the knee joint according to any one of claims 1 to 5.
[Requested item 7]
　The reduction ratio in the crank mechanism, the rotation angle has a configuration that varies depending on the said rotational movement
　knee joint according to any one of-claims 1 to 6.
[Requested item 8]
　Artificial leg comprising a knee joint according to any one of claims 1 to 7.