JP7610215B2 - Walking aids - Google Patents

Description

The present invention relates to a walking assistance device that assists the user in walking.

Patent Document 1 discloses a knee joint that includes an input cylinder that is placed at the sole of the foot, and an output cylinder that is placed between the thigh link and the crus link. In this knee joint, when the input cylinder is compressed by a floor reaction force during walking, the output cylinder generates an extension torque in the thigh link.

JP 2013-233421 A

The movement of the knee joint of a user when walking differs depending on the walking speed and stride length. However, in the knee joint of Patent Document 1, during the stance phase when the foot is on the ground and weight is being applied while walking, the input cylinder is compressed because the sole of the user's foot is on the ground, and the output cylinder extends in the direction that extends the knee joint, preventing the knee from bending. Therefore, the knee cannot bend while the sole of the foot is on the ground from when the heel touches the ground until the toe leaves, or from when the toe touches the ground until the heel leaves. In other words, it is difficult to change the movement to match the differences in the walking motion of the user.

The present invention was made in consideration of the above problems, and aims to provide a walking assistance device that can move in accordance with the differences in the walking movements of the user.

The present invention comprises a support member attached to the thigh of a user, a lower leg member connected to the support member so as to be rotatable in flexion and extension directions, a first hydraulic cylinder provided between the support member and the lower leg member and contracting when the lower leg member rotates in the flexion direction relative to the support member, and a switching valve having a main body and a spool that moves axially around the inner circumference of the main body, switching the flow of liquid in the first hydraulic cylinder depending on the position of the spool relative to the main body, and the switching valve has a blocking position where it blocks the flow of liquid when the first hydraulic cylinder attempts to contract, and a throttling position where it throttles the flow of liquid when the first hydraulic cylinder contracts.

In this invention, when the switching valve is switched to the blocking position, the flow of liquid is blocked when the first hydraulic cylinder tries to contract. Therefore, the lower leg member cannot rotate in the bending direction relative to the support member. On the other hand, when the switching valve is switched to the throttle position, the flow rate of liquid is throttled when the first hydraulic cylinder tries to contract. Therefore, the lower leg member rotates gently in the bending direction relative to the support member. In this way, by switching the switching valve between the blocking position and the throttle position, it is possible to move in accordance with the movement of the user's knee joint, which differs depending on the walking speed and stride length.

The present invention further comprises a foot member rotatably connected to the crus member in plantar flexion and dorsiflexion directions, a second hydraulic cylinder provided between the crus member and the foot member and contracting when the foot member rotates in the dorsiflexion direction relative to the crus member, a first communication passage connecting one side pressure chamber that discharges liquid when the first hydraulic cylinder contracts and one side pressure chamber that discharges liquid when the second hydraulic cylinder contracts, a second communication passage connecting the other side pressure chamber to which liquid is supplied when the first hydraulic cylinder contracts and the other side pressure chamber to which liquid is supplied when the second hydraulic cylinder contracts, and a third communication passage connecting the second communication passage and the first communication passage, and a switching valve provided in the third communication passage switches the flow of liquid from the first communication passage to the second communication passage.

In this invention, when a user walks forward, when the bottom of the foot member that has stepped forward touches the ground, the ankle joint rotates in the plantar flexion direction and the knee joint is slightly bent. When the user moves forward further, the ankle joint rotates in the dorsiflexion direction and the knee joint rotates in the extension direction. At this time, if the switching valve is switched to the cut-off position, as the second hydraulic cylinder gradually contracts, the liquid discharged from the second hydraulic cylinder moves to the first hydraulic cylinder via the first communication passage, causing the first hydraulic cylinder to gradually extend. Thus, the first hydraulic cylinder and the second hydraulic cylinder can cause the knee joint and the ankle joint to move in accordance with the walking motion of the user.

In addition, in the present invention, there are multiple throttling positions that each have a different amount of liquid squeezed out.

In this invention, for example, when a user descends stairs, the ankle joint is required to rotate in a dorsiflexion direction and the knee joint is required to rotate in a flexion direction. In such a case, by providing a switching valve with multiple throttling positions with different throttling amounts, the liquid discharged from one pressure chamber of the first hydraulic cylinder can be supplied to the other pressure chamber of the first hydraulic cylinder with a throttling amount that differs from that when walking on flat ground. Therefore, the user can use the walking assistance device to walk naturally not only when walking on flat ground but also when ascending and descending stairs.

In addition, in the present invention, the switching valve further includes a check valve that allows the flow of liquid when at least one of the first hydraulic cylinder and the second hydraulic cylinder expands and blocks the flow of liquid when the cylinder contracts.

In this invention, the check valve allows the first hydraulic cylinder to be extended regardless of the state of the second hydraulic cylinder. This allows the knee joint to be advanced quickly regardless of the movement of the ankle joint.

In the present invention, the check valve is provided axially along the central axis of the spool, and is provided within the inner circumferential passage that constitutes the third communication passage .

In this invention, the check valve is provided axially along the central axis of the spool, and is provided within the inner circumferential passage that constitutes the third communication passage , thereby making it possible to reduce the size and weight of the walking assist device.

The present invention further includes a first biasing member that biases the support member to rotate in an extension direction relative to the crus member, and a second biasing member that biases the foot member to rotate in a plantar flexion direction relative to the crus member.

In this invention, the first biasing member biases the support member in the extension direction relative to the lower leg member, and the second biasing member biases the foot member in the plantar flexion direction relative to the lower leg member, thereby returning the knee joint and ankle joint to their natural positions during the swing phase (when the foot leaves the ground).

In addition, in the present invention, the switching valve is attached to the first hydraulic cylinder so that the extension and contraction direction of the first hydraulic cylinder is the longitudinal direction.

In this invention, the longitudinal direction of the switching valve coincides with the extension and contraction direction of the first hydraulic cylinder, so the switching valve is provided along the first hydraulic cylinder and is prevented from protruding significantly from the first hydraulic cylinder.

The present invention also includes a pressure accumulator that is attached to the first hydraulic cylinder and stores liquid when at least one of the first hydraulic cylinder and the second hydraulic cylinder contracts, and the switching valve is provided in front of or behind the first hydraulic cylinder, and the pressure accumulator is provided at a position opposite the switching valve across the first hydraulic cylinder.

In this invention, the switching valve and the pressure accumulator are provided at the front and rear of the first hydraulic cylinder. This prevents the switching valve and the pressure accumulator from interfering with the bending and extending movements of the knee joint. In addition, the switching valve and the pressure accumulator are provided along the first hydraulic cylinder, allowing them to have a shape similar to that of an able-bodied person's leg.

The present invention provides a walking assistance device that can adapt to the differences in the walking movements of the user.

FIG. 1 is a right side view of a walking assistance device according to an embodiment of the present invention. FIG. 2 is a front view of FIG. FIG. 3 is a rear view of FIG. FIG. 4 is a diagram showing a state in which the lower leg member in FIG. 1 has rotated in a flexion direction and the foot member has rotated in a dorsiflexion direction. FIG. 5 is a diagram showing a state in which a length adjustment member is inserted into the walking assistance device of FIG. FIG. 6 shows a hydraulic circuit of a walking assistance device according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of the switching valve, showing a state in which the spool is in the shutoff position. FIG. 8 is a cross-sectional view of the switching valve, showing a state in which the spool is in the throttle position. FIG. 9 is a cross-sectional view of the switching valve showing a state in which the spool is in another throttle position. FIG. 10 is a cross-sectional view of the switching valve, showing a state in which the spool is in another throttle position. FIG. 11 is a cross-sectional view of the pressure accumulator.

Below, with reference to Figs. 1 to 11, a hydraulic prosthesis (hydraulic prosthesis) 1 as a walking assistance device according to an embodiment of the present invention will be described. In the hydraulic prosthesis 1, hydraulic oil is used as the liquid. As long as it is a non-compressible fluid, other liquids such as hydraulic water may be used instead of hydraulic oil.

In the following, the direction in which the lower leg is bent relative to the thigh (the direction in which the calf is brought closer to the thigh) is referred to as the "flexion direction," and the direction in which the lower leg is extended relative to the thigh (the direction in which the calf is moved away from the thigh) is referred to as the "extension direction." Additionally, the direction in which the foot is bent relative to the lower leg (the direction in which the toes are brought closer to the lower leg) is referred to as the "dorsiflexion direction," and the direction in which the foot is extended relative to the lower leg (the direction in which the toes are moved away from the lower leg) is referred to as the "plantar flexion direction." Additionally, the time when the foot is on the ground is referred to as the "stance phase," and the time when the foot is off the ground is referred to as the "swing phase."

First, the overall configuration of the hydraulic prosthesis 1 will be described with reference to Figures 1 to 5.

Figure 1 is a right side view of the hydraulic prosthesis 1. Figure 2 is a front view of Figure 1. Figure 3 is a rear view of Figure 1. Figure 4 is a diagram showing the state in Figure 1 where the lower leg member 3 has rotated in a flexion direction and the foot member 4 has rotated in a dorsiflexion direction. Figure 5 is a diagram showing the state in which the length adjustment member 33a has been inserted into the hydraulic prosthesis 1 of Figure 1.

As shown in Figures 1 to 3, the hydraulic prosthesis 1 is a thigh prosthesis used by a user who has had a thigh amputation in which the femur has been amputated. The hydraulic prosthesis 1 includes a support member 2, a lower leg member 3, a foot member 4, a knee joint portion 5, an ankle joint portion 6, a hydraulic cylinder 7 as a first hydraulic cylinder, a hydraulic cylinder 8 as a second hydraulic cylinder, a coil spring 9 as a first biasing member, a coil spring 10 as a second biasing member, a hydraulic circuit 100 (see Figure 6) as a hydraulic circuit, a switching valve 110, and an accumulator 140 as a pressure accumulator.

The support member 2 is attached to the user's thigh to support the thigh. A socket (not shown) is attached to the upper part of the support member 2, into which the stump (cut portion) of the user's thigh is attached. The support member 2 has a cylinder attachment part 21 to which the tip 72a (see FIG. 3) of the rod 72 of the hydraulic cylinder 7, which will be described later, is rotatably attached. The cylinder attachment part 21 is provided near the rear end part of the support member 2.

The support member 2 has a rotation restricting portion 22 that abuts against a rotation restricting portion 34a (described later) of the lower leg member 3. The rotation restricting portion 22 is provided near the front end portion of the support member 2. When the rotation restricting portion 22 abuts against the rotation restricting portion 34a of the lower leg member 3, it restricts the rotation of the lower leg member 3 in the extension direction (the state shown in FIG. 1).

The crus member 3 is connected to the support member 2 so as to be rotatable in the bending and extending directions. The crus member 3 has a first frame 31 that supports a cylinder portion 71 (one end) of the hydraulic cylinder 7, which will be described later, a second frame 32 that supports a cylinder portion 81 (one end) of the hydraulic cylinder 8, which will be described later, and a length adjustment mechanism 33 that is provided between the first frame 31 and the second frame 32.

The first frame 31 is connected to the support member 2 via a pivot shaft 51. The first frame 31 rotates relative to the support member 2 around the pivot shaft 51 (see FIG. 4). The first frame 31 has a pair of side members 34 and a lower end member 35 that connects the lower ends of the side members 34 together.

The side members 34 receive the weight of the user input through the support member 2. A hydraulic cylinder 7 is provided between the pair of side members 34. A cylinder support shaft 38 is inserted between the pair of side members 34. A cylinder portion 71 of the hydraulic cylinder 7 is rotatably connected to the cylinder support shaft 38.

The lower end member 35 supports the pair of side members 34 from below. The lower end member 35 faces the upper end member 37 (described later) of the second frame 32 in the vertical direction. The upper end portion 33b of the length adjustment mechanism 33 is connected to the lower end member 35.

The second frame 32 is connected to the lower part of the first frame 31 via a length adjustment mechanism 33. The second frame 32 has a pair of side members 36 and an upper end member 37 that connects the upper ends of the side members 36 together.

The side members 36 support the upper end member 37 from below. The side members 36 receive the weight of the user input through the upper end member 37. A hydraulic cylinder 8 is provided between the pair of side members 36. A cylinder support shaft 39 is inserted between the pair of side members 36. A cylinder portion 81 of the hydraulic cylinder 8 is rotatably connected to the cylinder support shaft 39.

The side member 36 has a rotation restricting portion 36a that abuts against a rotation restricting portion 41 of the foot member 4, which will be described later, and a rotation restricting portion 36b that abuts against a rotation restricting portion 42 of the foot member 4, which will be described later.

The upper end member 37 faces the lower end member 35 of the first frame 31 in the vertical direction. The lower end portion 33c of the length adjustment mechanism 33 is connected to the upper end member 37.

The length adjustment mechanism 33 has a length adjustment member 33a (see FIG. 5). In the length adjustment mechanism 33, the length adjustment member 33a can be replaced with one of a different length. This allows the lengths of the user's left and right legs to be matched by adjusting the length of the length adjustment member 33a according to the length of the user's opposite leg.

The first frame 31 supporting the cylinder portion 71 of the hydraulic cylinder 7 and the second frame 32 supporting the cylinder portion 81 of the hydraulic cylinder 8 are provided separately, sandwiching the length adjustment member 33a. Therefore, by adjusting the length adjustment member 33a, it is possible to change only the length of the lower leg member 3, without changing the size of the hydraulic cylinder 7 and the hydraulic cylinder 8.

The foot member 4 is connected to the crus member 3 so as to be rotatable in the plantar flexion and dorsiflexion directions. The foot member 4 is connected to the crus member 3 via a pivot shaft 61. The foot member 4 rotates relative to the crus member 3 around the pivot shaft 61 (see FIG. 4).

The foot member 4 is formed in the same shape as a healthy person's foot so that shoes and the like can be worn. The foot member 4 has a cylinder attachment part 43 to which a tip end 82a (see FIG. 1) of a rod 82 of a hydraulic cylinder 8, which will be described later, is rotatably attached. The cylinder attachment part 43 is provided forward of the position at which the foot member 4 is connected to the lower leg member 3 via the pivot shaft 61.

The foot member 4 has a rotation restricting portion 41 that abuts against the rotation restricting portion 36a of the lower leg member 3, and a rotation restricting portion 42 that abuts against the rotation restricting portion 36b of the lower leg member 3. The rotation restricting portion 41 is provided in front of the lower leg member 3. When the rotation restricting portion 41 abuts against the rotation restricting portion 36a of the lower leg member 3, it restricts the rotation of the foot member 4 in the dorsiflexion direction. The rotation restricting portion 42 is provided in the rear of the lower leg member 3. When the rotation restricting portion 42 abuts against the rotation restricting portion 36b of the lower leg member 3, it restricts the rotation of the foot member 4 in the plantar flexion direction.

The knee joint 5 has a pivot shaft 51. The pivot shaft 51 connects the support member 2 and the lower leg member 3 so that they can rotate in the flexion direction and extension direction.

The ankle joint 6 has a pivot shaft 61. The pivot shaft 61 connects the lower leg member 3 and the foot member 4 so that they can rotate in the plantar flexion and dorsiflexion directions.

The hydraulic cylinder 7 is provided between the support member 2 and the lower leg member 3. When the hydraulic cylinder 7 contracts, the lower leg member 3 rotates in a bending direction relative to the support member 2. When the hydraulic cylinder 7 expands, the lower leg member 3 rotates in an extension direction relative to the support member 2. The hydraulic cylinder 7 has a cylinder portion 71 and a rod 72.

The cylinder section 71 is provided between the pair of side members 34. The cylinder section 71 will be described in detail later with reference to the hydraulic circuit 100 in FIG. 6.

The rod 72 advances and retreats relative to the cylinder portion 71. When the rod 72 retreats from the cylinder portion 71, the hydraulic cylinder 7 extends. On the other hand, when the rod 72 advances into the cylinder portion 71, the hydraulic cylinder 7 contracts.

The hydraulic cylinder 7 is fitted with a switching valve 110 and an accumulator 140. The switching valve 110 and the accumulator 140 are provided integrally with the hydraulic cylinder 7. Alternatively, the switching valve 110 and the accumulator 140 may be attached to the hydraulic cylinder 8.

The switching valve 110 is attached to the hydraulic cylinder 7 so that the extension direction of the hydraulic cylinder 7 is the longitudinal direction. As a result, the longitudinal direction of the switching valve 110 coincides with the extension direction of the hydraulic cylinder 7, so the switching valve 110 is provided along the hydraulic cylinder 7 and can be prevented from protruding significantly from the hydraulic cylinder 7.

The accumulator 140 stores hydraulic oil when at least one of the hydraulic cylinders 7 and 8 contracts.

The switching valve 110 is provided in front of the hydraulic cylinder 7, and the accumulator 140 is provided behind the hydraulic cylinder 7. Alternatively, the switching valve 110 may be provided behind the hydraulic cylinder 7, and the accumulator 140 may be provided in front of the hydraulic cylinder 7. That is, the switching valve 110 is provided in front or behind the hydraulic cylinder 7, and the accumulator 140 is provided on the opposite side of the hydraulic cylinder 7 to the switching valve 110. This prevents the switching valve 110 and the accumulator 140 from interfering with the bending and extending movements of the knee joint 5. In addition, the switching valve 110 and the accumulator 140 are provided along the hydraulic cylinder 7, and can be shaped similarly to the legs of an able-bodied person.

The specific configuration of the switching valve 110 and the accumulator 140 will be described in detail later with reference to Figures 7 to 11.

The hydraulic cylinder 8 is provided between the lower leg member 3 and the foot member 4. The hydraulic cylinder 8 contracts when the foot member 4 rotates in the dorsiflexion direction relative to the lower leg member 3. The hydraulic cylinder 8 extends when the foot member 4 rotates in the plantarflexion direction relative to the lower leg member 3. The hydraulic cylinder 8 has a cylinder portion 81 and a rod 82.

The cylinder section 81 is provided between the pair of side members 36. The cylinder section 81 will be described in detail later with reference to the hydraulic circuit 100 in FIG. 6.

The rod 82 advances and retreats relative to the cylinder portion 81. When the rod 82 retreats from the cylinder portion 81, the hydraulic cylinder 8 extends. On the other hand, when the rod 82 advances into the cylinder portion 81, the hydraulic cylinder 8 contracts.

The hydraulic cylinder 8 has a shorter overall length than the hydraulic cylinder 7. This allows the hydraulic cylinder 8 to be accommodated in the ankle joint 6, which has a smaller space than the accommodation section for the hydraulic cylinder 7. The hydraulic cylinders 7 and 8 can be set according to the walking movement of the user by changing the diameters of the cylinder sections 71, 81.

The coil spring 9 is provided on the outer periphery of the rod 72. The coil spring 9 biases the support member 2 to rotate in the extension direction relative to the lower leg member 3. When the rod 72 exits the cylinder portion 71, the coil spring 9 expands together with the extension of the rod 72. On the other hand, when the rod 72 enters the cylinder portion 71, the coil spring 9 contracts together with the contraction of the rod 72.

The coil spring 10 is provided on the outer periphery of the rod 82. The coil spring 10 biases the foot member 4 to rotate in the plantar flexion direction relative to the crus member 3. When the rod 82 exits the cylinder portion 81, the coil spring 10 expands together with the extension of the rod 82. On the other hand, when the rod 82 enters the cylinder portion 81, the coil spring 10 contracts together with the contraction of the rod 82.

The coil spring 9 biases the support member 2 in the extension direction relative to the lower leg member 3, and the coil spring 10 biases the foot member 4 in the plantar flexion direction relative to the lower leg member 3, thereby allowing the knee joint 5 and the ankle joint 6 to return to their natural positions during the swing phase.

Instead of the coil springs 9 and 10, other springs may be provided as the first and second biasing members. Furthermore, the coil springs 9 and 10 may be provided independently at positions separate from the hydraulic cylinders 7 and 8, rather than on the outer periphery of the rods 72 and 82.

Next, the hydraulic circuit 100 of the hydraulic prosthesis 1 will be described with reference to Figure 6. Figure 6 shows the hydraulic circuit 100 of the hydraulic prosthesis 1.

The hydraulic circuit 100 moves hydraulic oil in response to the operation of the hydraulic cylinder 7 and the hydraulic cylinder 8. The hydraulic circuit 100 includes a first communication passage 101, a second communication passage 102, a third communication passage 103, a switching valve 110, and an accumulator 140.

The hydraulic cylinder 7 has a cylinder portion 71, a rod 72, a piston 73, a piston side chamber 74 as one pressure chamber, and a rod side chamber 75 as the other pressure chamber.

The rod 72 is integral with the piston 73 and extends outside the cylinder portion 71. The piston 73 slides inside the cylinder portion 71. The piston 73 defines a piston side chamber 74 and a rod side chamber 75 inside the cylinder portion 71. The piston side chamber 74 discharges hydraulic oil when the hydraulic cylinder 7 contracts. The rod side chamber 75 is supplied with hydraulic oil when the hydraulic cylinder 7 contracts.

The hydraulic cylinder 8 has a cylinder portion 81, a rod 82, a piston 83, a piston side chamber 84 as one pressure chamber, and a rod side chamber 85 as the other pressure chamber.

The rod 82 is integral with the piston 83 and extends outside the cylinder portion 81. The piston 83 slides inside the cylinder portion 81. The piston 83 defines a piston side chamber 84 and a rod side chamber 85 inside the cylinder portion 81. The piston side chamber 84 discharges hydraulic oil when the hydraulic cylinder 8 contracts. The rod side chamber 85 is supplied with hydraulic oil when the hydraulic cylinder 8 contracts.

The first communication passage 101 connects the piston side chamber 74 of the hydraulic cylinder 7 to the piston side chamber 84 of the hydraulic cylinder 8. The second communication passage 102 connects the rod side chamber 75 of the hydraulic cylinder 7 to the rod side chamber 85 of the hydraulic cylinder 8.

When the hydraulic cylinder 8 contracts, hydraulic oil moves from the piston side chamber 84 to the piston side chamber 74 through the first communication passage 101, and hydraulic oil moves from the rod side chamber 75 to the rod side chamber 85 through the second communication passage 102, causing the hydraulic cylinder 7 to extend. On the other hand, when the hydraulic cylinder 8 extends, hydraulic oil moves from the piston side chamber 74 to the piston side chamber 84 through the first communication passage 101, and hydraulic oil moves from the rod side chamber 85 to the piston side chamber 84 through the second communication passage 102, causing the hydraulic cylinder 7 to contract.

The third communication passage 103 connects the second communication passage 102 and the first communication passage 101. The third communication passage 103 is provided with a bridge passage 108 that branches off from the third communication passage 103 and reconnects to the third communication passage 103.

The switching valve 110 is provided in the third communication passage 103 and switches the flow of hydraulic oil from the first communication passage 101 to the second communication passage 102. The switching valve 110 has a blocking position 110a and a plurality of throttling positions, namely, a first throttling position 110b, a second throttling position 110c, and a third throttling position 110d. That is, the switching valve 110 has the blocking position 110a that blocks the flow of hydraulic oil when at least one of the hydraulic cylinder 7 and the hydraulic cylinder 8 is about to contract, and the throttling positions 110b, 110c, and 110d that throttle the flow rate of hydraulic oil when at least one of the hydraulic cylinder 7 and the hydraulic cylinder 8 is contracted. A common check valve 130 is provided for the blocking position 110a, the first throttling position 110b, the second throttling position 110c, and the third throttling position 110d.

The check valve 130 is provided in the bridge passage 108. The check valve 130 blocks the flow of hydraulic oil so that hydraulic oil does not flow from the first communication passage 101 to the second communication passage 102, and allows hydraulic oil to flow only from the second communication passage 102 to the first communication passage 101. In other words, the check valve 130 allows the flow of hydraulic oil when at least one of the hydraulic cylinders 7 and 8 expands, and blocks the flow of hydraulic oil when it contracts.

In the blocking position 110a, the flow of hydraulic oil from the second communication passage 102 to the first communication passage 101 is permitted by the check valve 130, and the flow of hydraulic oil from the first communication passage 101 to the second communication passage 102 is blocked by the check valve 130.

At the first throttling position 110b, the flow of hydraulic oil from the second communication passage 102 to the first communication passage 101 is permitted by the check valve 130, and the flow of hydraulic oil from the first communication passage 101 to the second communication passage 102 is throttled by the first throttle 105.

The first throttle 105 throttles the hydraulic oil flowing from the first communication passage 101 to the second communication passage 102. That is, the hydraulic oil throttled by the first throttle 105 flows from the first communication passage 101 to the second communication passage 102.

At the second throttling position 110c, the flow of hydraulic oil from the second communication passage 102 to the first communication passage 101 is permitted by the check valve 130, and the flow of hydraulic oil from the first communication passage 101 to the second communication passage 102 is throttled by the second throttle 106.

The second throttle 106 throttles the hydraulic oil flowing from the first communication passage 101 to the second communication passage 102. That is, hydraulic oil throttled by the second throttle 106 flows from the first communication passage 101 to the second communication passage 102. The throttle amount of the second throttle 106 is smaller than the throttle amount of the first throttle 105. Therefore, at the second throttle position 110c, the flow rate of hydraulic oil from the first communication passage 101 to the second communication passage 102 is greater than at the first throttle position 110b.

At the third throttling position 110d, the flow of hydraulic oil from the second communication passage 102 to the first communication passage 101 is permitted by the check valve 130, and the flow of hydraulic oil from the first communication passage 101 to the second communication passage 102 is throttled by the third throttle 107.

The third throttle 107 throttles the hydraulic oil flowing from the first communication passage 101 to the second communication passage 102. That is, hydraulic oil throttled by the third throttle 107 flows from the first communication passage 101 to the second communication passage 102. The throttle amount of the third throttle 107 is smaller than the throttle amount of the second throttle 106. Therefore, at the third throttle position 110d, the flow rate of hydraulic oil from the first communication passage 101 to the second communication passage 102 is even greater than at the second throttle position 110c.

The accumulator 140 is provided so as to communicate with the second communication passage 102. The accumulator 140 compensates for the change in volume of the hydraulic oil in the hydraulic circuit 100, which changes according to the length of advancement and retreat of the rods 72 and 82 relative to the cylinder portions 71 and 81. That is, the accumulator 140 stores hydraulic oil when at least one of the hydraulic cylinders 7 and 8 contracts. The accumulator 140 also compensates for the change in volume of the hydraulic oil due to temperature changes.

Next, the specific configuration of the switching valve 110 will be described with reference to Figures 7 to 10.

Figure 7 is a cross-sectional view of the switching valve 110, showing the spool 121 in the shutoff position 110a. Figure 8 is a cross-sectional view of the switching valve 110, showing the spool 121 in the first throttling position 110b. Figure 9 is a cross-sectional view of the switching valve 110, showing the spool 121 in the second throttling position 110c. Figure 10 is a cross-sectional view of the switching valve 110, showing the spool 121 in the third throttling position 110d.

As shown in FIG. 7, the switching valve 110 has a first housing 111 as a main body, a second housing 117, a spool 121, a return spring 118, a wire 119, and a check valve 130.

The first housing 111 is formed in a cylindrical shape with a spool hole 112 on the inner circumference. The first housing 111 has a first piston side port 111a, a first rod side port 111b, a second piston side port 111c, a second rod side port 111d, a spool hole 112, a first connection port 113a, a second connection port 113b, a third connection port 113c, a fourth connection port 113d, and a fifth connection port 113e.

The first piston side port 111a opens to the outside of the first housing 111 and communicates directly with the piston side chamber 74 of the hydraulic cylinder 7. The first rod side port 111b opens to the outside of the first housing 111 and communicates directly with the rod side chamber 75 of the hydraulic cylinder 7. The second piston side port 111c opens to the outside of the first housing 111 and communicates with the piston side chamber 84 of the hydraulic cylinder 8 through external piping (not shown). The second rod side port 111d opens to the outside of the first housing 111 and communicates with the rod side chamber 85 of the hydraulic cylinder 8 through external piping (not shown).

The spool hole 112 is a through hole whose both ends open to the end faces of the first housing 111. A spool 121 is provided in the spool hole 112 so that it can move axially.

The first connection port 113a opens into the spool hole 112 and communicates with the first piston side port 111a via the bridge passage 108. The second connection port 113b opens into the spool hole 112 and communicates with the first rod side port 111b. The third connection port 113c opens into the spool hole 112 and communicates with the second piston side port 111c. The fourth connection port 113d opens into the spool hole 112 and communicates with the second rod side port 111d. The fifth connection port 113e opens into the spool hole 112 and communicates with the first piston side port 111a.

Regardless of the position of the spool 121, the first connection port 113a is always in communication with the third connection port 113c via the first annular groove 122a described below. Therefore, the piston side chamber 74 of the hydraulic cylinder 7 and the piston side chamber 84 of the hydraulic cylinder 8 are always in communication. In other words, the passage connecting the first connection port 113a, the first annular groove 122a, and the third connection port 113c corresponds to the first communication passage 101.

Regardless of the position of the spool 121, the second connection port 113b is always in communication with the fourth connection port 113d via the fifth annular groove 122e (described later). Therefore, the rod side chamber 75 of the hydraulic cylinder 7 and the rod side chamber 85 of the hydraulic cylinder 8 are always in communication. In other words, the passage connecting the second connection port 113b, the fifth annular groove 122e, and the fourth connection port 113d corresponds to the second communication passage 102.

The second housing 117 is formed in a cylindrical shape with a bottom and closes one opening of the first housing 111. The second housing 117 has a recess 117a into which the spool 121 can enter. The recess 117a accommodates a return spring 118. A wire 119 is inserted into the axial end of the second housing 117.

The spool 121 is formed in a generally cylindrical shape. The spool 121 moves along the inner circumference of the spool hole 112 formed in the first housing 111. The spool 121 has a first land portion 121a, a second land portion 121b, a third land portion 121c, a fourth land portion 121d, a fifth land portion 121e, a sixth land portion 121f, and an inner circumferential passage 123. The first land portion 121a, the second land portion 121b, the third land portion 121c, the fourth land portion 121d, the fifth land portion 121e, and the sixth land portion 121f are in sliding contact with the inner circumference of the spool hole 112.

A first annular groove 122a is formed between the first land portion 121a and the second land portion 121b. A second annular groove 122b is formed between the second land portion 121b and the third land portion 121c. A third annular groove 122c is formed between the third land portion 121c and the fourth land portion 121d. A fourth annular groove 122d is formed between the fourth land portion 121d and the fifth land portion 121e. A fifth annular groove 122e is formed between the fifth land portion 121e and the sixth land portion 121f.

The inner circumferential passage 123 is provided axially along the central axis of the spool 121. The inner circumferential passage 123 connects the first annular groove 122a and the fifth annular groove 122e via the check valve 130. In other words, the inner circumferential passage 123 corresponds to the third communication passage 103.

The spool 121 also has a first aperture 105, a second aperture 106, and a third aperture 107.

The first throttle 105 connects the second annular groove 122b to the inner circumferential passage 123. The second throttle 106 connects the third annular groove 122c to the inner circumferential passage 123. The third throttle 107 connects the fourth annular groove 122d to the inner circumferential passage 123. The first throttle 105, the second throttle 106, and the third throttle 107 connect to the fifth connection port 113e depending on the position of the spool 121 relative to the first housing 111. That is, the switching valve 110 switches the flow of hydraulic oil in the hydraulic cylinder 7 depending on the position of the spool 121 relative to the first housing 111.

The first throttle 105, the second throttle 106, and the third throttle 107 are each set to a predetermined throttle amount depending on the length of the throttle. Alternatively, the first throttle 105, the second throttle 106, and the third throttle 107 may each be set to a predetermined throttle amount by changing the flow path area of the throttle. The first throttle 105, the second throttle 106, and the third throttle 107 are provided at equal intervals in the axial direction of the spool 121. The order of the first throttle 105, the second throttle 106, and the third throttle 107 can be arbitrarily changed to an order that is easy for the user to operate. Also, since it is sufficient that multiple throttles 105, 106, and 107 are provided, the number may be two, four or more.

The return spring 118 biases the spool 121 in a direction away from the second housing 117.

The wire 119 is connected to the end of the spool 121 on the second housing 117 side. The wire 119 is pulled out by a user. The wire 119 is pulled out by a rotary or linear operating unit (not shown) that can adjust the amount of wire pulled out in stages. It is also possible to use a switching device (not shown) that can pull the wire 119 out by an electric motor, for example. In this case, the switching device adjusts the amount of wire 119 pulled out in stages based on the switch operation by the user.

As shown in FIG. 7, when the wire 119 is not pulled out, the switching valve 110 is switched to the shutoff position 110a.

At this time, the spool 121 does not connect the fifth connection port 113e to any of the second annular groove 122b, the third annular groove 122c, and the fourth annular groove 122d. In other words, no hydraulic oil flows through any of the first throttle 105, the second throttle 106, and the third throttle 107.

As shown in FIG. 8, when the user pulls out the wire 119, the spool 121 moves and the switching valve 110 is switched to the first throttling position 110b. At this time, the spool 121 connects the fifth connection port 113e to the fourth annular groove 122d. In other words, hydraulic oil flows through the first throttling 105.

As shown in FIG. 9, when the user pulls out the wire 119 further, the spool 121 moves further and the switching valve 110 is switched to the second throttling position 110c. At this time, the spool 121 connects the fifth connection port 113e to the third annular groove 122c. In other words, hydraulic oil flows through the second throttling 106.

As shown in FIG. 10, when the user pulls out the wire 119 further, the spool 121 moves further and the switching valve 110 is switched to the third throttling position 110d. At this time, the spool 121 connects the fifth connection port 113e to the second annular groove 122b. In other words, hydraulic oil flows through the third throttling 107.

Returning to FIG. 7, the check valve 130 allows hydraulic oil to flow when at least one of the hydraulic cylinders 7 and 8 extends and blocks the flow of hydraulic oil when the other extends. The check valve 130 is provided in the spool 121. Providing the check valve 130 in the spool 121 makes it possible to reduce the size and weight of the hydraulic prosthesis 1. The check valve 130 has a valve seat 131, a valve body 132, and a compression spring 133.

The valve seat 131 is provided at the end of the inner circumferential passage 123. The valve seat 131 is formed so that its diameter expands from the end of the inner circumferential passage 123.

When the valve body 132 is seated on the valve seat 131, it blocks the third communication passage 103. When the valve body 132 is spaced from the valve seat 131, it opens the third communication passage 103.

The compression spring 133 biases the valve body 132 toward the valve seat 131. When the pressure of the hydraulic oil in the inner circumferential passage 123 overcomes the biasing force of the compression spring 133, the compression spring 133 is compressed and the valve body 132 moves away from the valve seat 131. This allows hydraulic oil to flow from the second communication passage 102 through the third communication passage 103 to the first communication passage 101.

In this way, by providing the check valve 130, the hydraulic cylinder 7 can be extended regardless of the state of the hydraulic cylinder 8. Therefore, the operation of advancing the knee joint 5 can be performed quickly regardless of the movement of the ankle joint 6. Also, by providing the check valve 130, the hydraulic cylinder 8 can be extended regardless of the state of the hydraulic cylinder 7. Therefore, the operation of plantar flexing the ankle joint 6 can be performed quickly regardless of the movement of the knee joint 5.

Next, the specific configuration of the accumulator 140 will be described with reference to FIG. 11.

The accumulator 140 has a housing 141, a piston 142, a compression spring 143, and a rod 144.

The housing 141 is formed into a cylindrical shape along the inner circumference of which the piston 142 can slide. One end of the housing 141 is closed by a plug 145. The housing 141 has a communication passage 141a that communicates with the rod side chamber 75 of the hydraulic cylinder 7.

The piston 142 moves in the central axial direction on the inner circumference of the housing 141. Between the piston 142 and the plug 145, an accumulator chamber 146 is formed that stores hydraulic oil.

The compression spring 143 biases the piston 142 in a direction approaching the plug 145, i.e., in a direction that reduces the volume of the pressure accumulation chamber 146.

When no hydraulic oil is flowing from the communication passage 141a into the accumulator chamber 146, the piston 142 abuts against the top surface 145a of the plug 145 due to the biasing force of the compression spring 143. At this time, the piston 142 stops at a height that does not block the communication between the accumulator chamber 146 and the communication passage 141a. When hydraulic oil flows into the accumulator chamber 146, the pressure of the hydraulic oil overcomes the biasing force of the compression spring 143, and the piston 142 moves in a direction away from the plug 145. This increases the volume of the accumulator chamber 146, allowing hydraulic oil to be stored.

The rod 144 protrudes to the outside of the housing 141. The rod 144 is fixed to the piston 142 and moves together with the piston 142. The more hydraulic oil flows into the pressure accumulator chamber 146, the more the rod 144 protrudes to the outside. This allows the user to check how much hydraulic oil is stored in the pressure accumulator chamber 146 based on the amount that the rod 144 protrudes.

Next, we will explain the walking motion using the hydraulic prosthetic leg 1.

First, we will explain the case where a user wearing a hydraulic prosthetic leg 1 on one leg walks on flat ground.

When the user walks forward, the user steps forward with one leg fitted with the hydraulic prosthetic leg 1, after stepping forward with the other leg. When the bottom of the foot member 4 that has stepped forward touches the ground, the ankle joint 6 has rotated in the plantar flexion direction and the knee joint 5 has been slightly bent. If the user moves further forward from this state, the ankle joint 6 rotates in the dorsiflexion direction and the knee joint 5 rotates in the extension direction.

When the walking speed is slow or the stride is small, the user switches the switching valve 110 to the shutoff position 110a. When the switching valve 110 is switched to the shutoff position 110a, the hydraulic cylinder 8 gradually contracts, and the hydraulic oil discharged from the hydraulic cylinder 8 moves to the hydraulic cylinder 7 via the first communication passage 101. This causes the hydraulic cylinder 7 to gradually expand.

In this way, when the switching valve 110 is switched to the shutoff position 110a, the hydraulic cylinder 7 gradually expands as the hydraulic cylinder 8 gradually contracts. Therefore, the hydraulic cylinders 7 and 8 can cause the knee joint 5 and the ankle joint 6 to move in accordance with the walking motion of the user.

On the other hand, when the walking speed is fast or the stride is large, the user switches the switching valve 110 to the second throttle position 110c or the third throttle position 110d. When the switching valve 110 is switched to the second throttle position 110c or the third throttle position 110d, the hydraulic oil discharged from the piston side chamber 74 of the hydraulic cylinder 7 can be supplied to the rod side chamber 75 through the second throttle 106 or the third throttle 107. This allows the ankle joint 6 to rotate in the dorsiflexion direction and the knee joint 5 to rotate in the flexion direction.

In this way, when the user switches the switching valve 110 to the second throttling position 110c or the third throttling position 110d, the flow rate of hydraulic oil is throttled when the hydraulic cylinder 7 attempts to contract. As a result, the lower leg member 3 rotates gently in the bending direction relative to the support member 2. In this way, by switching the switching valve 110 to the second throttling position 110c or the third throttling position 110d, the hydraulic prosthetic leg 1 can move in accordance with the movement of the user's knee joint 5, which differs depending on differences in walking speed and stride length. Therefore, it is possible to provide a hydraulic prosthetic leg 1 that can move in accordance with differences in the walking movements of the user.

Next, we will explain the case where a user wearing a hydraulic prosthetic leg 1 on one leg ascends and descends stairs.

When the user is going up stairs, the user switches the switching valve 110 to the shutoff position 110a. When the switching valve 110 is switched to the shutoff position 110a, the hydraulic cylinder 8 gradually contracts, and the hydraulic oil discharged from the hydraulic cylinder 8 moves to the hydraulic cylinder 7 via the first communication passage 101. This causes the hydraulic cylinder 7 to gradually expand. In addition, the hydraulic prosthesis 1 is stable in an upright position because the knee joint 5 does not rotate in the bending direction without linking with the movement of the ankle joint 6. Therefore, even when going up stairs, the user can walk naturally using the hydraulic prosthesis 1.

On the other hand, when the user descends the stairs, the user switches the switching valve 110 to the first throttle position 110b. When the switching valve 110 is switched to the first throttle position 110b or the third throttle position 110d, the hydraulic oil discharged from the piston side chamber 74 of the hydraulic cylinder 7 can be supplied to the rod side chamber 75 through the first throttle 105. Therefore, the ankle joint 6 can rotate in the dorsiflexion direction and the knee joint 5 can rotate in the flexion direction. In addition, since the knee joint 5 of the hydraulic prosthesis 1 slowly rotates in the flexion direction without linking with the movement of the ankle joint 6, the leg on the lower step can be slowly flexed. Therefore, even when descending stairs, the user can walk naturally using the hydraulic prosthesis 1.

In this way, the switching valve 110 has multiple throttling positions 110b, 110c, 110d with different throttling amounts, so that the hydraulic oil discharged from the piston side chamber 74 of the hydraulic cylinder 7 can be supplied to the rod side chamber 75 of the hydraulic cylinder 7 with a throttling amount that differs from that when walking on flat ground. Therefore, the user can walk naturally using the hydraulic prosthesis 1 not only when walking on flat ground, but also when ascending and descending stairs.

The configuration, operation, and effects of the embodiment of the present invention are summarized below.

The hydraulic prosthesis 1 includes a support member 2 attached to the user's thigh, a lower leg member 3 connected to the support member 2 so as to be rotatable in the bending and extending directions, a hydraulic cylinder 7 provided between the support member 2 and the lower leg member 3 and contracting when the lower leg member 3 rotates in the bending direction relative to the support member 2, a first housing 111 and a spool 121 moving on the inner circumference of the first housing 111, and a switching valve 110 that switches the flow of hydraulic oil in the hydraulic cylinder 7 depending on the position of the spool 121 relative to the first housing 111. The switching valve 110 has a blocking position 110a that blocks the flow of hydraulic oil when the hydraulic cylinder 7 is about to contract, and throttling positions 110b, 110c, and 110d that throttle the flow of hydraulic oil when the hydraulic cylinder 7 contracts.

In this configuration, when the switching valve 110 is switched to the blocking position 110a, the flow of hydraulic oil is blocked when the hydraulic cylinder 7 is about to contract. Therefore, the lower leg member 3 cannot rotate in the bending direction relative to the support member 2. On the other hand, when the switching valve 110 is switched to the throttle position 110b, 110c, or 110d, the flow rate of hydraulic oil is throttled when the hydraulic cylinder 7 is about to contract. Therefore, the lower leg member 3 rotates gently in the bending direction relative to the support member 2. In this way, by switching the switching valve 110 between the blocking position 110a and the throttle position 110b, 110c, or 110d, it is possible to move in accordance with the movement of the knee joint 5 of the user, which differs depending on the walking speed and stride length. Therefore, it is possible to provide a hydraulic prosthesis 1 that can move in accordance with the difference in the walking motion of the user.

The hydraulic prosthesis 1 further includes a foot member 4 that is connected to the lower leg member 3 so as to be rotatable in the plantar flexion direction and the dorsiflexion direction; a hydraulic cylinder 8 that is provided between the lower leg member 3 and the foot member 4 and that contracts when the foot member 4 rotates in the dorsiflexion direction relative to the lower leg member 3; a first communication passage 101 that connects the piston side chamber 74 that discharges hydraulic oil when the hydraulic cylinder 7 contracts and the piston side chamber 84 that discharges hydraulic oil when the hydraulic cylinder 8 contracts; a second communication passage 102 that connects the rod side chamber 75 to which hydraulic oil is supplied when the hydraulic cylinder 7 contracts and the rod side chamber 85 to which hydraulic oil is supplied when the hydraulic cylinder 8 contracts; and a third communication passage 103 that connects the second communication passage 102 and the first communication passage 101. A switching valve 110 is provided in the third communication passage 103 and switches the flow of hydraulic oil flowing from the first communication passage 101 to the second communication passage 102.

In this configuration, when the user walks forward, when the bottom of the foot member 4 that has stepped forward touches the ground, the ankle joint 6 rotates in the plantar flexion direction and the knee joint 5 is slightly bent. When the user moves forward further, the ankle joint 6 rotates in the dorsiflexion direction and the knee joint 5 rotates in the extension direction. At this time, if the switching valve 110 is switched to the shutoff position 110a, as the hydraulic cylinder 8 gradually contracts, the hydraulic oil discharged from the hydraulic cylinder 8 moves to the hydraulic cylinder 7 via the first communication passage 101, causing the hydraulic cylinder 7 to gradually expand. Thus, the hydraulic cylinder 7 and the hydraulic cylinder 8 can cause the knee joint 5 and the ankle joint 6 to move in accordance with the walking motion of the user.

In addition, the hydraulic prosthesis 1 has multiple throttling positions 110b, 110c, and 110d that have different amounts of hydraulic oil throttling.

In this configuration, for example, when a user descends stairs, the ankle joint 6 is required to rotate in the dorsiflexion direction and the knee joint 5 is required to rotate in the flexion direction. In such a case, the switching valve 110 has multiple throttling positions 110b, 110c, 110d with different throttling amounts, so that the hydraulic oil discharged from the piston side chamber 74 of the hydraulic cylinder 7 can be supplied to the rod side chamber 75 of the hydraulic cylinder 7 with a throttling amount that differs from that when walking on flat ground. Therefore, the user can walk naturally using the hydraulic prosthesis 1 not only when walking on flat ground but also when ascending and descending stairs.

In addition, in the hydraulic prosthesis 1, the switching valve 110 further includes a check valve 130 that allows the flow of hydraulic oil when at least one of the hydraulic cylinders 7 and 8 extends and blocks the flow of hydraulic oil when it contracts.

In this configuration, the check valve 130 is provided, so that the hydraulic cylinder 7 can be extended regardless of the state of the hydraulic cylinder 8. This allows the knee joint 5 to be advanced quickly regardless of the movement of the ankle joint 6.

In addition, in the hydraulic prosthesis 1, the check valve 130 is provided within the spool 121.

In this configuration, the check valve 130 is provided inside the spool 121, making it possible to reduce the size and weight of the hydraulic prosthesis 1.

The hydraulic prosthetic leg 1 further includes a coil spring 9 that biases the support member 2 to rotate in the extension direction relative to the lower leg member 3, and a coil spring 10 that biases the foot member 4 to rotate in the plantar flexion direction relative to the lower leg member 3.

In this configuration, the coil spring 9 biases the support member 2 in the extension direction relative to the lower leg member 3, and the coil spring 10 biases the foot member 4 in the plantar flexion direction relative to the lower leg member 3, thereby allowing the knee joint 5 and the ankle joint 6 to return to their natural positions during the swing phase.

In addition, in the hydraulic prosthesis 1, the switching valve 110 is attached to the hydraulic cylinder 7 so that the extension direction of the hydraulic cylinder 7 is the longitudinal direction.

In this configuration, the longitudinal direction of the switching valve 110 coincides with the extension and contraction direction of the hydraulic cylinder 7, so the switching valve 110 is provided along the hydraulic cylinder 7 and is prevented from protruding significantly from the hydraulic cylinder 7.

The hydraulic prosthesis 1 further includes an accumulator 140 that is attached to the hydraulic cylinder 7 and stores hydraulic oil when at least one of the hydraulic cylinders 7 and 8 contracts, and the switching valve 110 is provided in front of or behind the hydraulic cylinder 7, and the accumulator 140 is provided at a position opposite the switching valve 110 across the hydraulic cylinder 7.

In this configuration, the switching valve 110 and the accumulator 140 are provided at the front and rear of the hydraulic cylinder 7. This prevents the switching valve 110 and the accumulator 140 from interfering with the bending and extending movements of the knee joint 5. In addition, the switching valve 110 and the accumulator 140 are provided along the hydraulic cylinder 7, allowing them to be shaped similarly to the legs of an able-bodied person.

Although the embodiments of the present invention have been described above, the above embodiments merely show some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

For example, in the above embodiment, the hydraulic prosthesis 1 is described as having a hydraulic cylinder 7 and a hydraulic cylinder 8, but the switching valve 110 and the accumulator 140 may be provided in a hydraulic prosthesis that has only a hydraulic cylinder 7 and a fixed ankle joint 6.

In this case, when the user walks on flat ground, the switching valve 110 can be switched between the shutoff position 110a and the throttle positions 110b, 110c, and 110d to match the movement of the knee joint 5 of the user, which differs depending on the walking speed and stride length. Therefore, in this case as well, a hydraulic prosthetic leg can be provided that can match the movement of the user's walking motion.

The hydraulic cylinder 7 may also be arranged so that the cylinder portion 71 is attached to the support member 2 and the rod 72 is attached to the lower leg member 3. Similarly, the hydraulic cylinder 8 may be arranged so that the cylinder portion 81 is attached to the foot member 4 and the rod 82 is attached to the lower leg member 3.

In this case, in the hydraulic cylinders 7 and 8, the rods 72 and 82 correspond to one end, the rod side chambers 75 and 85 correspond to one side pressure chambers, and the piston side chambers 74 and 84 correspond to the other side pressure chambers.

The walking assistance device is not limited to the hydraulic prosthetic leg 1, but may be a power assist device used by users with weak leg strength, such as disabled people or the elderly. The power assist device may also be used by able-bodied people to reduce the load of walking. In this case, the support member 2 is provided along the user's thigh and attached to the thigh from the outside, the lower leg member 3 is provided along the user's lower leg and attached to the lower leg from the outside, and the foot member 4 is provided along the user's foot and attached to the foot from the outside. This makes it possible to assist the user's walking movement with natural movements.

The hydraulic circuit 100 of this embodiment can also be applied to a power assist device that assists the movement of the user's arm rather than assisting the user's walking movement. In this case, a member corresponding to the support member 2 is provided along the user's upper arm and attached to the upper arm from the outside, a member corresponding to the lower leg member 3 is provided along the user's forearm and attached to the forearm from the outside, and a member corresponding to the foot member 4 is provided along the user's hand and attached to the hand from the outside.

1...hydraulic prosthesis (hydraulic prosthesis, walking assistance device), 2...support member, 3...lower leg member, 4...foot member, 7...hydraulic cylinder (first hydraulic cylinder), 8...hydraulic cylinder (second hydraulic cylinder), 9...coil spring (first biasing member), 10...coil spring (second biasing member), 74...piston side chamber (one side pressure chamber), 75...rod side chamber (other side pressure chamber), 84...piston side chamber (one side pressure chamber), 85...rod side chamber (other side pressure chamber), 102...second communication passage, 103...third communication passage, 110...switching valve, 110a...shutoff position, 110b...first throttle position, 110c...second throttle position, 110d...third throttle position, 111...first housing (main body), 121...spool, 130...check valve, 140...accumulator (pressure storage device)

Claims (8)

A support member attached to the thigh of a user;
A lower leg member rotatably connected to the support member in a bending direction and an extension direction;
a first hydraulic cylinder provided between the support member and the lower leg member, the first hydraulic cylinder contracting when the lower leg member rotates in a bending direction relative to the support member;
a switching valve including a main body and a spool that moves in an axial direction on an inner periphery of the main body, the switching valve switching a flow of liquid in the first hydraulic cylinder depending on a position of the spool relative to the main body;
Equipped with
The switching valve has a blocking position at which the flow of liquid is blocked when the first hydraulic cylinder is about to contract, and a throttling position at which the flow rate of liquid is throttled when the first hydraulic cylinder is contracting.
A walking assistance device characterized by: 2. The walking assistance device according to claim 1,
a foot member rotatably connected to the lower leg member in a plantar flexion direction and a dorsiflexion direction;
a second hydraulic cylinder provided between the lower leg member and the foot member, the second hydraulic cylinder contracting when the foot member rotates in a dorsiflexion direction relative to the lower leg member;
a first communication passage that communicates between one pressure chamber that discharges liquid when the first hydraulic cylinder contracts and one pressure chamber that discharges liquid when the second hydraulic cylinder contracts;
a second communication passage that communicates between the other-side pressure chamber to which liquid is supplied when the first hydraulic cylinder contracts and the other-side pressure chamber to which liquid is supplied when the second hydraulic cylinder contracts;
a third communication passage that communicates the second communication passage with the first communication passage;
Further comprising:
the switching valve is provided in the third communication passage and switches the flow of liquid from the first communication passage to the second communication passage;
A walking assistance device characterized by: 3. The walking assistance device according to claim 2,
The throttling position includes a plurality of throttling positions each having a different amount of liquid throttling.
A walking assistance device characterized by: 4. The walking assistance device according to claim 2 or 3,
The switching valve further includes a check valve that allows a flow of liquid when at least one of the first hydraulic cylinder and the second hydraulic cylinder extends and blocks a flow of liquid when the at least one of the first hydraulic cylinder and the second hydraulic cylinder contracts.
A walking assistance device characterized by: 5. The walking assistance device according to claim 4,
The check valve is provided in an axial direction along a central axis of the spool, and is provided in an inner circumferential passage that constitutes the third communication passage .
A walking assistance device characterized by: 6. A walking assistance device according to claim 2,
A first biasing member biases the support member so as to rotate in an extension direction relative to the lower leg member;
A second biasing member biases the foot member so as to rotate in a plantar flexion direction relative to the crus member;
Further comprising:
A walking assistance device characterized by: 7. A walking assistance device according to claim 2,
The switching valve is attached to the first hydraulic cylinder such that the extension and contraction direction of the first hydraulic cylinder is a longitudinal direction.
A walking assistance device characterized by: A walking assistance device according to any one of claims 2 to 7,
a pressure accumulator attached to the first hydraulic cylinder and configured to accumulate liquid when at least one of the first hydraulic cylinder and the second hydraulic cylinder is contracted;
The switching valve is provided in front of or behind the first hydraulic cylinder,
The pressure accumulator is provided at a position opposite to the switching valve across the first hydraulic cylinder.
A walking assistance device characterized by:

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