JP7217651B2 - actuator - Google Patents

Description

The present invention relates to actuators applicable to artificial muscles.

BACKGROUND ART In recent years, as part of hydraulic and pneumatic technology, research and development of fluid-driven actuators that operate as artificial muscles are underway. In place of the conventional cigar-shaped McKibben type that inflates in all directions, this actuator has plastic plates attached to the upper and lower surfaces of a low-elastic bellows-shaped inflatable body, and an artificial muscle in place of a sleeve between these plastic plates. It has a configuration with a pair of extremities as. A pair of extremities extend in opposite directions (horizontal direction) in a direction (horizontal direction) intersecting with the expansion/contraction direction (longitudinal direction) of the inflatable body, and each base end is branched vertically to form upper and lower surfaces of the inflatable body, respectively. attached to a plastic plate. When the inflatable body expands, the branched part of the extremity approaches the inflatable body, and when the inflatable body contracts, the branched part of the extremity separates from the inflatable body, and as a result, the tips of the pair of extensible extremities expand and contract in the lateral direction. , with a structure capable of generating a contractile force.

Kazuyuki Mitsui, "Fundamental Research on the Development of Artificial Muscle Using EHD Pump as a Drive Source", 2017 Spring Fluid Power System Conference Proceedings, Japan Fluid Power System Society, May 25, 2017 , p. 34-36

However, in the actuator disclosed in Non-Patent Document 1, the exfoliation of the extensible extremity in the horizontal direction between the plastic plates in conjunction with the expansion and contraction of the inflatable body causes the extremity of the extremity to move from the bifurcation of the extremity to the proximal end of the extremity. It has a structure in which the angle to the parts of the upper and lower plastic plates to which is attached can be changed. For this reason, the design of the contraction force that can be generated by the actuator and the calculation of the contraction rate become very complicated, so there is still room for improvement in manufacturing an actuator with high controllability that can exhibit the desired performance. rice field.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an actuator that facilitates calculation of contractile force and contraction rate, has high controllability, and can exhibit desired performance.

An actuator according to the present invention includes an inflatable body that expands in a predetermined direction when a fluid is filled therein and contracts in the predetermined direction when the fluid is discharged to the outside, and both ends of the inflatable body in the expansion and contraction direction. at least one pair of artificial muscles each having one end directly or indirectly attached to at least one of the portions and having the other ends extending in directions opposite to contraction/relaxation directions intersecting the contraction/relaxation direction; and a direction changing guide member that guides the inflatable body in the expansion/contraction direction from one end toward the other end and changes the direction in the contraction/relaxation direction.

In one embodiment of the present invention, a pair of plate members are provided at the ends of the inflatable body, and one end of the artificial muscle is attached to at least one of the pair of plate members.

In another embodiment of the present invention, the direction changing guide member is provided on a ring member disposed between the pair of plate members and through which the inflatable member is inserted.

In still another embodiment of the present invention, the direction changing guide member is provided on one of the pair of plate members.

In yet another embodiment of the invention, the inflatable body comprises a bellows or bellofram.

In yet another embodiment of the present invention, the fluid is charged into and discharged from the inflatable body by an EHD pump, and the fluid enters and exits the inflatable body at either one of the ends in the expansion and contraction direction. Alternatively, it is provided in an intermediate portion between the two ends.

According to the present invention, it is possible to easily calculate the shrinkage force and the shrinkage rate, to achieve high controllability, and to exhibit desired performance.

It is a perspective view showing roughly the whole actuator composition concerning one embodiment of the present invention. FIG. 3 is a diagram schematically showing a cross section taken along the line A-A' of FIG. 2; It is a perspective view which shows roughly the state at the time of the maximum contraction of the same actuator. It is a perspective view which shows roughly the whole structure of the modification of the same actuator. It is a perspective view which shows roughly the mode at the time of the maximum contraction of the modification of the same actuator. FIG. 5 is a perspective view schematically showing the overall configuration of an actuator according to another embodiment of the invention; It is a perspective view which shows roughly the state at the time of the maximum contraction of the same actuator. It is a perspective view which shows roughly the whole structure of the modification of the same actuator.

Hereinafter, actuators according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments do not limit the invention according to each claim, and not all combinations of features described in the embodiments are essential to the solution of the invention. . Also, in the drawings, the scale and dimensions of each component may be exaggerated, and some components may be omitted.

As shown in FIG. 1, an actuator 1 according to an embodiment of the present invention includes a bellows 11, an upper plate 12, a lower plate 13, and a pair of string-like or belt-like members functioning as artificial muscles. Then, the extremities 14 (14a, 14b) are provided. The actuator 1 also includes a ring 19 having guides 18 through which the strings 14a and 14b are respectively inserted.

The actuator 1 can be used as, for example, artificial muscles, and is connected to an EHD (Electro Hydro Dynamics) pump 30 as a power source (working fluid source). The EHD pump 30 includes a bidirectional EHD pump that can switch the direction Fd of the flow of working fluid indicated by the arrow Fd in FIG. 1 by switching the switch 31 .

That is, if the bidirectional EHD pump is used, the fluid pumped into the bellows 11 can be drawn out by suction only with the pump, and the structure can be made without the need for additional devices other than the pump. The EHD pump 30 is connected to a power source 50 capable of applying a high voltage (several kV to several tens of kV) and a reservoir 40 capable of storing working fluid such as insulating liquid.

It should be noted that the power source of the actuator 1 is not limited to the EHD pump 30, as long as it can supply and discharge a working fluid such as gas or liquid that can expand and contract the actuator 1 to and from the actuator 1. Various types of power sources may be employed.

The bellows 11 of the actuator 1 expands in a predetermined direction (here, the expansion/contraction direction indicated by the arrow Vd in FIG. 1) by filling the inside with working fluid through a tubular fluid inlet/outlet portion 11f having a fluid inlet/outlet. Also, it functions as an inflatable body that contracts in the expansion/contraction direction Vd when the working fluid is discharged to the outside through the fluid inlet/outlet portion 11f. The bellows 11 is made of soft polyurethane or the like having a weaker elastic force than an elastic body such as rubber (elastomer).

By adopting the above-mentioned dual EHD pump as the EHD pump 30 and combining it with the bellows 11, it is not necessary to make the expanded body of the artificial muscle an elastic body, so that it is possible to use the conventional McKibben type artificial muscle. Since it is no longer necessary to apply a high pressure on the order of MPa, the actuator 1 can be operated at a low pressure.

Specifically, the bellows 11 is formed in a bellows-like cylindrical structure having, for example, two tiered ridges 11a and 11b that are vertically connected and one trough 11c that exists between the ridges 11a and 11b. ing. The fluid inlet/outlet portion 11f of the bellows 11 is provided so as to extend along the expansion/contraction direction Vd through the center hole 12b of the upper plate 12 from the upper end side of the peak portion 11a. The bellows 11 is deformed so as to expand and contract in the expansion/contraction direction Vd, but it is difficult to expand/contract in the contraction/relaxation direction indicated by the arrow Hd in FIG. It has

The contraction/relaxation direction Hd indicates the direction in which the extremities 14 (14a, 14b) contract and relax as artificial muscles. Moreover, the bellows 11 is not limited to a cylindrical structure, and other structures such as a polygonal structure may be employed. Furthermore, the inflatable body is not limited to the bellows 11, and may have a structure, such as a bellofram, which has the above-mentioned characteristic that the force is more difficult to disperse than the structure of the conventional McKibben type. Various things can be adopted.

The upper plate 12 and the lower plate 13 are attached to both ends (the upper end of the peak portion 11a and the lower end portion of the peak portion 11b) of the bellows 11 in the expansion/contraction direction Vd via an adhesive or the like. function as a pair of plate members. The upper plate 12 and the lower plate 13 are attached so that their plate surfaces are kept parallel to each other as much as possible. With this configuration, the bellows 11 generates forces on the upper plate 12 and the lower plate 13 respectively when inflated. The upper plate 12 and the lower plate 13 are provided with wire end fixing portions 12a and 13a, respectively, which are formed so as to protrude along the desired contraction/relaxation direction Hd.

The extremities 14 (14a, 14b) are wires made of a material such as nylon that are hard to stretch and have high tensile strength. The strings 14 (14a, 14b) each have one end attached directly or indirectly via a plate member or the like to at least one of both end portions of the bellows 11 in the expansion/contraction direction Vd, and each other end is attached in the contraction/relaxation direction Hd. It has a structure extending in opposite directions to each other. Here, specifically, the extremities 14 (14a, 14b) are attached to the upper plate 12 and the lower plate 13 at their ends, respectively, between the upper plate 12 and the lower plate 13, and then the bellows 11 expands and contracts. , it expands and contracts along the expansion/contraction direction Vd and expands/contracts along the contraction/relaxation direction Hd.

Specifically, the extremity 14 of the actuator 1 is composed of a pair of extensible extremities 14a and 14b that can extend and contract in opposite directions via the bellows 11 along one contraction/relaxation direction Hd.

The lines 14a and 14b are inserted into the guides 18 between the upper plate 12 and the lower plate 13, for example, and drawn outward in the contraction/relaxation direction Hd. The guide 18 functions as a direction changing guide member that changes the direction of the lines 14a and 14b. Specifically, the guide 18 has a structure capable of changing the stretching direction of the lines 14a and 14b from the expansion/contraction direction Vd to the contraction/relaxation direction Hd.

The guides 18 are arranged, for example, on the outer peripheral side of the trough portion 11c of the bellows 11 and provided on the outer peripheral side of the ring 19, which is a ring member through which the bellows 11 is inserted. Here, the structure of the string 14 will be described by focusing on the string 14a which is a part of the string 14. As shown in FIG.

As shown in FIG. 2, the line 14a has an upper line 14a2 and a lower line 14a3, and has a structure in which one ends of the upper and lower lines 14a2 and 14a3 are connected to each other via a connection fixing point 14a1. The other ends of the upper and lower extremities 14a2 and 14a3 are fixed to the extremity fixing portions 12a and 13a of the upper plate 12 and the lower plate 13 by adhesion or the like.

The upper and lower lines 14a2 and 14a3 are fixed to the end fixing portions 12a and 13a of the lines and are inserted into and aligned with a guide hole 18a having a T-shaped vertical cross section formed in the guide 18, along the contraction/relaxation direction Hd. , and are connected to each other at connection fixing points 14a1 so as to be integrated with the extremities 14a.

As a result, the portions of the upper and lower lines 14a2 and 14a3 that appear closer to the line end fixing portions 12a and 13a than the guides 18 expand and contract along the direction of expansion and contraction Vd as indicated by the arrows in the drawing. The upper and lower lines 14a2 and 14a3 of the upper and lower lines 14a2 and 14a3 of the upper and lower lines 14a2 and 14a3 of the upper and lower lines 14a2 and 14a3, respectively, appearing outwardly from the guide 18 along the contraction/relaxation direction Hd. Stretch.

In addition, as shown in FIGS. 1 and 3, such a structure of the extremity 14a also has an upper extremity 14b2 and a lower extremity 14b3 in the other extremity 14b, and the structure connected at the connection fixing point 14b1 is Since it is the same, the explanation is omitted here.

The state of the actuator 1 when the bellows 11 expands the most is shown in FIG. 1, and the state when the bellows 11 contracts the most is shown in FIG. On the other hand, the extremities 14 (14a, 14b) are in the most contracted state as shown in FIG. 1, and the most relaxed state as shown in FIG.

The actuator 1 according to this embodiment has the following advantages by being configured as described above. That is, since the bellows 11 has a bellows shape and is made of soft polyurethane, it has a structure that expands in the stretching direction Vd but hardly expands in the contracting and relaxing direction Hd, and has a small elastic force to reduce resistance when expanding. can be done.

In addition, the contraction ratio of the bellows 11 can be made uniform, and since the upper plate 12 and the lower plate 13 are attached to the ends, the contact area with the bellows 11 and the unit area thereof From the applied fluid pressure, Pascal's law makes it possible to easily calculate the contractile force. Furthermore, there is no instability that the force that can be exerted varies depending on the degree of contraction of the bellows 11, and the force that can be exerted can be determined only by the pressure of the fluid that is filled and discharged inside, so the controllability is improved. A high actuator 1 can be realized.

Since the actuator 1 has the extremities 14 (14a, 14b) as artificial muscles, the bellows 11 that operates along the stretching direction Vd exerts a contractile force along the contracting and relaxing direction Hd. Since the artificial muscle can contract and relax as a working artificial muscle, it is possible to reduce the overall size of the device as the artificial muscle. Also, in this example, the lines 14 (14a, 14b) are connected to the upper plate 12 and the lower plate 13 through the guides 18 provided on the ring 19 so that the expansion/contraction direction Vd and the contraction/relaxation direction Hd are always kept at 90°. Since it is provided between them, it is easy to calculate the contraction force and contraction rate, and for example, force can be uniformly applied to the threads 14 (14a, 14b) regardless of the contraction rate. For example, if a structure that generates force in one direction is used as a reference, a structure that generates force in two directions will have about half the contractile force of a structure that generates force in one direction. It can facilitate various calculations such as can be considered. Further, the extremities 14 (14a, 14b) as artificial muscles extend along the expansion/contraction direction Vd of the bellows 11, which is the inflatable member, and along the contraction/relaxation direction Hd intersecting (perpendicular to) the bellows 11 via the guide 18. Therefore, the contractile force of the line 14 with respect to the pressure applied to the bellows 11 can be made linear.

Thus, according to the actuator 1 according to this embodiment, it is possible to provide a structure in which the pressure on the bellows 11 and the contractile force of the extremities 14 are proportional. Therefore, for example, when the actuator 1 is used as an artificial muscle, it is possible to realize an artificial muscle with high versatility due to miniaturization and high controllability due to its structure.

The actuator 1 according to this embodiment can also be configured as follows, for example. Here, constituent elements that are the same as or correspond to those of the actuator 1 of the previous example are given the same reference numerals or the reference numerals are omitted to omit redundant description.
As shown in FIGS. 4 and 5, the actuator 1A of the modified example is provided with two lines 14 and 15, and two different contraction/relaxation directions Hd of these lines 14 and 15 intersect the expansion/contraction direction Vd. The fact that they are arranged at 90° intervals in the horizontal direction is different from that in the actuator 1 of the previous example, where the extremities 14 were arranged so as to expand and contract in one contraction and relaxation direction Hd.

As in the actuator 1A of this modified example, even if the artificial muscle can contract and relax in two different contraction and relaxation directions Hd using the strings 14 and 15, the actuator 1A can be operated by connecting an EHD pump 30, for example. For example, it is possible to obtain the same effect as the actuator 1 of the previous example. The actuator 1A may have a structure including a plurality of extremities that can contract and relax in two or more directions.

Next, actuators according to other embodiments of the present invention will be described. In the following description, the same or corresponding components as those of the actuators 1 and 1A according to the previous embodiments may be denoted by the same reference numerals, and overlapping descriptions may be omitted.
As shown in FIGS. 6 and 7, in an actuator 1B according to another embodiment of the present invention, the ring 19 is omitted and the guide 18 is directly provided on the top plate 12, which is the same as the actuator 1 ( and 1A) in that the guide 18 is provided on the ring 19. FIG. Specifically, the actuator 1B has, for example, two different contraction/relaxation directions Hd, each of which stretches and contracts 14 (14a, 14b) and 15 (15a, 15b). It is fixed to the string end fixing portion 13a of the lower plate 13, respectively.

Guides 18 are directly fixed to the lower surface of the portion of the upper plate 12 corresponding to the wire end fixing portion 12a. Each of the lines 14 and 15 has a portion extending from the lower plate 13 to the guide 18 extending along the expansion/contraction direction Vd, and a portion extending outward from the guide 18 in the contraction/relaxation direction Hd along the contraction/relaxation direction Hd. . Although illustration is omitted, the guide hole 18a of this example is formed, for example, in an L-shaped longitudinal section.

The state of the actuator 1B when the bellows 11 expands the most is shown in FIG. 6, and the state when the bellows 11 contracts the most is shown in FIG. On the other hand, the extremities 14 and 15 are in the most contracted state as shown in FIG. 6, and the most relaxed state as shown in FIG.

In the actuator 1B constructed in this manner, the strokes of the threads 14 and 15 are doubled compared to the actuator 1A, but the bellows 11 exerts force only on the lower plate 13 and the upper plate 12 is not moved. Therefore, the contractile force is considered to be 1/2. However, other portions can achieve the same effects as the actuator 1A of the previous example. Also, in the actuator 1B, the number of extremities can be set to two or more to allow contraction and relaxation in multiple directions.

The actuator 1B can also be configured as follows, for example.
As shown in FIG. 8, in the modified actuator 1C, the fluid inlet/outlet portion 11f of the bellows 11 protrudes outward along the contraction/relaxation direction Hd into the valley portion 11c, which is the intermediate portion between the peak portions 11a and 11b. In the actuator 1B of the previous example, the fluid inlet/outlet portion 11f is provided so as to extend from the upper end side of the peak portion 11a through the center hole 12b of the upper plate 12 along the expansion/contraction direction Vd. It is different from what is stated.

As in the actuator 1C of this modified example, if the fluid inlet/outlet portion 11f is provided in the valley portion 11c between the peak portions 11a and 11b of the bellows 11 to expand/contract the bellows 11, the peak portions 11a and 11b can be Since it becomes possible to apply the pressure by the fluid more uniformly, it becomes possible to control the operation of the bellows 11 more accurately.

It should be noted that such a structure of the fluid inlet/outlet portion 11f can also be applied to the actuators 1 and 1A of the previous examples. In that case, for example, a hole is provided in a part of the ring 19 to allow the fluid inlet/outlet portion 11f from the valley portion 11c to pass therethrough, or a part of the ring 19 is notched to guide the fluid inlet/outlet portion 11f from the valley portion 11c. Just do it.

Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

For example, the actuators 1B and 1C described above have a structure in which the guide 18 is directly fixed to the upper plate 12. The guide 18 may be fixed to the lower surface and attached to the upper end side of the mountain portion 11a of the bellows 11, or the guide 18 may be arranged on the lower plate 13 side instead of the upper plate 12 side.

Reference Signs List 1, 1A, 1B, 1C actuator 11 bellows 11a, 11b peak 11c valley 12 upper plate 12a, 13a wire end fixing portion 12b center hole 13 lower plate 14, 15 wire 18 guide 19 ring 30 EHD pump 31 switch 40 reservoir 50 power supply

Claims (6)

an inflatable body that expands in a predetermined direction when filled with a fluid and contracts in the predetermined direction when the fluid is discharged to the outside;
At least one pair of artificial muscles each having one end attached directly or indirectly to at least one of both ends in the expansion/contraction direction of the expandable body, and having the other ends extending in directions opposite to contraction/relaxation directions intersecting the expansion/contraction direction. and,
and a direction changing guide member that guides the artificial muscle from the one end to the other end in the expansion/contraction direction of the expandable body and changes the direction in the contraction/relaxation direction. comprising a pair of plate members provided at both ends of the inflatable body,
2. The actuator according to claim 1, wherein one end of said artificial muscle is attached to at least one of said pair of plate members. 3. The actuator according to claim 2, wherein the direction changing guide member is provided on a ring member arranged between the pair of plate members and through which the expansion body is inserted. 3. The actuator according to claim 2, wherein the direction changing guide member is provided on one of the pair of plate members. The actuator according to any one of claims 1 to 4, wherein the expandable body comprises a bellows or a bellofram. the fluid is filled and discharged from the inflatable body by an EHD pump;
6. The inflatable body according to any one of claims 1 to 5, wherein an inlet/outlet for the fluid is provided at either one of the two ends in the expansion/contraction direction or at an intermediate portion between the two ends. Actuator according to paragraph.

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