Fluid pressure actuator

Abstract

To provide a fluid pressure actuator that can easily return to a shape of extending in an axial direction even when the fluid pressure actuator is repeatedly deformed from an axially extending state into a direction crossing with the axial direction.SOLUTION: A sleeve 26 of a fluid pressure actuator 20 includes a first group WA and a second group WE. The respective yarn materials W of the first group WA and the second group WE are crossed alternately. When a fluid pressure applied to a tube 24 is maximum, a length X1 in a direction φ orthogonal to an extension direction θ and a radial direction R of the yarn material W is four times or less of a length Y1 in the radial direction.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a fluid pressure actuator.

Background Art

[0002] Patent Document 1 discloses a fluid pressure actuator including a cylindrical tube that expands and contracts by the pressure of a fluid, a stretchable structure in which fiber cords oriented in a predetermined direction are woven, a sleeve that covers the outer peripheral surface of the tube, and a sealing member that seals the end portions in the axial direction of the tube. Inside the sleeve, a restraint member is provided that extends from one end side to the other end side in the axial direction. The restraint member resists compression along the axial direction and is deformable in a direction orthogonal to the axial direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration described in Patent Document 1, when the fluid pressure actuator is repeatedly deformed from a state extending in the axial direction to a direction intersecting the axial direction, the fluid pressure actuator is likely to have a habit of the deformed shape. In this case, when the fluid pressure actuator has a habit of the deformed shape, even if the pressure of the fluid applied to the fluid pressure actuator is removed, the fluid pressure actuator is unlikely to return to the shape extending in the axial direction.

[0005] Here, the discloser of the present disclosure has discovered that by applying the technical matters disclosed below to a fluid pressure actuator, it is possible to obtain a fluid pressure actuator that easily returns to a shape extended in the axial direction, even when the fluid pressure actuator is repeatedly deformed from a state extended in the axial direction in a direction intersecting the axial direction.

[0006] The present disclosure aims to provide a fluid pressure actuator that easily returns to an axially extended shape even when the fluid pressure actuator is repeatedly deformed from an axially extended state in a direction intersecting the axial direction. [Means for solving the problem]

[0007] A first aspect of the fluid pressure actuator is a fluid pressure actuator comprising: a cylindrical tube that expands and contracts in response to fluid pressure; a sleeve that covers the outer peripheral surface of the tube and expands the tube radially while restricting its axial extension as the tube expands; a plate-shaped restraining member that is provided radially inside the sleeve from one side in the axial direction to the other side, resists compression along the axial direction, and is deformable in a transverse direction that intersects the axial direction; and a pair of sealing members that seal the ends of the tube on one side and the other side in the axial direction, respectively, and have an insertion portion into which the tube is inserted. The sleeve has a group of thread material oriented in one direction and a group of other thread materials oriented in another direction that intersects the group of thread materials, and is formed by alternatingly intersecting the group of thread materials and the group of other thread materials, and when the pressure of the fluid applied to the tube is at a maximum, the length of each of the thread materials in the extension direction of the thread material and in the direction perpendicular to the radial direction is four times or less than its length in the radial direction.

[0008] In the fluid pressure actuator according to the present disclosure, it has a sleeve formed by alternately intersecting yarn materials. Further, each yarn material of the sleeve has a length in a direction orthogonal to the extending direction and the radial direction of the yarn material being 4 times or less the length in the radial direction when the pressure of the fluid applied to the tube is maximum. In other words, in the fluid pressure actuator according to the present disclosure, when the pressure of the fluid applied to the tube is maximum, the ratio of the length of the yarn material in the direction orthogonal to the extending direction and the radial direction to the length in the radial direction is 4 or less. For this reason, since it becomes difficult for the yarn materials to slip due to bending deformation, the position of the intersection of the yarn materials in the sleeve is relatively difficult to change.

[0009] Therefore, in the fluid pressure actuator according to the present disclosure, even when the fluid pressure actuator is repeatedly deformed from the axially extending state to a direction intersecting the axial direction, the fluid pressure actuator easily returns to the axially extending shape.

[0010] The fluid pressure actuator of the third aspect is the fluid pressure actuator according to the first aspect or the second aspect, wherein the yarn material has a twist coefficient of 100 or more.

[0011] According to this fluid pressure actuator, since the bias of the yarn material due to repeated operation is prevented, the effect of suppressing the formation of a habit can be obtained.

[0012] The fluid pressure actuator of the fourth aspect is the fluid pressure actuator according to any one of the first aspect to the third aspect, wherein the yarn material has a thickness of 1000 dtex or more.

[0013] According to this fluid pressure actuator, in repeated operation, the effects of preventing wear and breakage due to the yarn material being too thin and preventing the formation of a habit due to the bias of the yarn material can be obtained.

Advantages of the Invention

[0014] According to the present disclosure, it is possible to provide a fluid pressure actuator that easily returns to an axially extended shape even when the fluid pressure actuator is repeatedly deformed from an axially extended state to a direction intersecting the axial direction.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments for realizing the technology of the present disclosure will be described in detail with reference to the drawings.

[0017] In addition, for components and processes that perform the same functions, the same reference numerals are given throughout the drawings, and duplicate descriptions may be omitted as appropriate. Further, the present disclosure is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present disclosure.

[0018] In each drawing, the arrow S indicates the direction in which the fluid pressure actuator extends. The arrow X is a direction orthogonal to the arrow S and indicates the direction that becomes the inner side of the curvature when the fluid pressure actuator is curved. The arrow R is a direction orthogonal to the arrow S and indicates the radial direction of the sleeve in the fluid pressure actuator. The arrow θ1 indicates the direction in which the group of first yarn materials constituting the sleeve in the fluid pressure actuator is oriented with respect to the direction in which the fluid pressure actuator extends, and the arrow θ2 indicates the direction in which the group of second yarn materials constituting the sleeve in the fluid pressure actuator is oriented.

[0019] In the following description, the "initial state" refers to the state in which the fluid pressure actuator has not been curved and deformed at all after the fluid pressure actuator is assembled. In the following description, the "curved state" refers to the state in which the internal pressure of the tube of the fluid pressure actuator has risen and the fluid pressure actuator has been curved and deformed. In the following description, "recovery" refers to the state in which the pressure in the tube of the curved and deformed fluid pressure actuator is reduced to atmospheric pressure to eliminate the curvature. In the following description, the "extended state" refers to the state in which the fluid pressure actuator has been restored after being curved from the initial state and the curvature has been eliminated.

[0020] <Configuration of Fluid Pressure Actuator> FIG. 1 shows a fluid pressure actuator 20 of the present disclosure. The fluid pressure actuator 20 includes an actuator main body portion 22, a first sealing portion 30A, and a second sealing portion 30B.

[0021] As also shown in Fig. 2, the actuator body 22 has a tube 24, a sleeve 26, and a restraint member 28. The tube 24 is a cylindrical shape that can expand and contract by elastic deformation, and expands and contracts due to a change in the pressure of the fluid inside. The axial direction of the tube 24 is defined as the "axial direction S". The tube 24 can be made of an elastic material such as butyl rubber. As the fluid supplied to the tube 24, air can be used, and in this case, the fluid pressure actuator 20 becomes a pneumatic actuator. When the fluid pressure actuator 20 is hydraulically driven, it is preferably at least one selected from the group consisting of NBR (nitrile rubber) with high oil resistance, hydrogenated NBR, chloroprene rubber, and epichlorohydrin rubber. It is preferably at least one kind.

[0022] As the cord constituting the sleeve 26, it is preferable to use a fiber cord of aromatic polyamide (aramid fiber) or polyethylene terephthalate (PET). However, it is not limited to such types of fiber cords, and for example, cords of other high-strength fibers such as PBO fiber (polyparaphenylene benzobisoxazole) may also be used.

[0023] The restraint member 28 is provided between the tube 24 and the sleeve 26. The restraint member 28 is in the shape of a long plate, and its longitudinal direction is arranged along the axial direction of the tube 24. It covers a part of the outer periphery of the tube 24 and is arranged from one end to the other end of the tube 24.

[0024] The restraint member 28 is formed of a material that does not expand / contract by pressurization, and is capable of flexural deformation in the direction in which the ends approach each other. As the restraint member 28, a so-called leaf spring can be used. The dimensions of the leaf spring are determined according to the size of the fluid pressure actuator 20, the required output, etc. Also, the material of the leaf spring is not particularly limited, but typically, a material such as metal like stainless steel, which is easy to flexurally deform and strong against compression, may be used. Alternatively, it may be formed of a thin plate of carbon fiber reinforced plastic (CFRP).

[0025] The first sealing portion 30A has a first sealing member 32, a locking ring 34, and a caulking member 36. It is.

[0026] The first sealing member 32 has an integrally formed lid portion 32A and an insertion portion 32B. The lid portion 32A is formed in a hexagonal column shape with a diameter larger than the outer diameter of the tube 24, and an insertion portion 32B extends from the center of one end side of the lid portion 32A in the axial direction S. The insertion portion 32B has a so-called bamboo shoot shape and is inserted into one end side of the tube 24 inside the sleeve 26. A mounting portion 38 is formed on the side of the lid portion 32A opposite to the insertion portion 32B. A mounting hole 38A penetrating in a direction orthogonal to the axial direction S is formed in the mounting portion 38. As the first sealing member 32, a metal such as stainless steel can be preferably used, but it is not limited to such a metal, and a hard plastic material or the like may be used.

[0027] As shown in FIG. 3, the first sealing member 32 has a flow path F. The flow path F is formed to extend axially in the radial center portion of the insertion portion 32B and is communicated with a connection hole H on the side surface of the lid portion 32A. An air supply hose (not shown) is connected to the connection hole H, and compressed air is supplied.

[0028] The locking ring 34 has a ring shape and is disposed outside the sleeve 26 so as to sandwich the sleeve 26 between the locking ring 34 and the insertion portion 32B, and locks the sleeve 26 to the first sealing member 32. The sleeve 26 is folded back to the outer periphery via the locking ring 34. As the locking ring 34, materials such as metal, hard plastic, fiber, and rubber can be used.

[0029] The caulking member 36 is disposed so as to cover the portion where the insertion portion 32B is inserted on the outer periphery of the actuator main body portion 22, and caulks the actuator main body portion 22 to the first sealing member 32. Thereby, the actuator main body portion 22 is fixed to the first sealing member 32. As the caulking member 36, metals such as aluminum alloy, brass, and iron can be used.

[0030] The second sealing portion 30B has a second sealing member 33, a locking ring 34, and a caulking member 36. The second sealing member 33 is the same as the first sealing member 32 of the first sealing portion 30A, except that the connection hole H and the flow path F are not formed and the tip of the lid portion 33A has an R shape.

[0031] The sleeve 26 is cylindrical and covers the outer periphery of the tube 24. The sleeve 26 is a stretchable structure in which fiber cords oriented in a predetermined direction are woven, and the oriented cords intersect at a predetermined angle with respect to the axial direction S.

[0032] More specifically, as shown in FIG. 4, the sleeve 26 has a first group WA which is a group of yarn materials W oriented in the first direction θ1, and a second group WE which is a group of yarn materials W oriented in the second direction θ2 intersecting the first direction θ1. In other words, the first direction θ1 is the direction that winds clockwise as viewed from the axial direction S and heads toward the axial direction S, and the second direction θ2 is the direction that winds counterclockwise as viewed from the axial direction S and heads toward the axial direction S. Note that the first direction θ1 and the second direction θ2 are symmetric with respect to the axial direction S. Further, the first group WA is an example of the "group of yarn materials oriented in one direction" in the present embodiment, and the second group WE is an example of the "group of other yarn materials oriented in the other direction" in the present embodiment.

[0033] The yarn materials W of the first group WA and the yarn materials W of the second group WE are alternately interlaced with each other, and the sleeve 26 is formed by intersecting at a predetermined angle with respect to the axial direction S. Note that the interval M at which the yarn materials W of the first group WA and the yarn materials W of the second group WE are interlaced is appropriately set according to the specifications of the fluid pressure actuator 20. By having such a shape, the sleeve 26 deforms like a pantograph that changes the angle, and follows the contraction and expansion of the tube 24 while restricting the contraction and expansion.

[0034] In addition, in the present embodiment, the yarn material W of the first group WA and the yarn material W of the second group WE are both formed by combining a plurality of filaments. The twist coefficient of this yarn material W is, for example, 100 or more, preferably 120 or more. Further, the thickness of the twisted yarn material W is, for example, 700 dtex or more, preferably 1000 dtex or more.

[0035] Note that the twist coefficient is obtained by the following formula.

[0036]

Equation

[0037] In the above formula (1), C is the twist coefficient, Tw is the number of twists (T / m), and Th is the thickness of the yarn material (dtex).

[0038] <Operation of the fluid pressure actuator> The fluid pressure actuator 20 is used such that the first sealing portion 30A on one end side is fixed by the mounting portion 38, and the second sealing portion 30B on the other end side becomes a free end.

[0039] As shown in FIG. 3, when compressed air is introduced into the tube 24 from the connection hole H, the pressure inside the fluid pressure actuator 20 rises. Due to the increase in the internal pressure, the tube 24 elastically deforms and expands, and the sleeve 26 deforms so that the angle between the aligned yarn materials W increases, and a force acts in the direction in which the length L0 (length when not shortened) of the actuator main body portion 22 is shortened. At this time, since the shortening of the outer peripheral side wall where the restraining member 28 of the actuator main body portion 22 is arranged is restricted, the actuator main body portion 22 shortens the outer peripheral wall on the side where the restraining member 28 is not arranged as viewed from the axial direction S. As a result, the restraining member 28 bends and deforms, and as shown by the two-dot chain line in FIG. 3, the entire actuator main body portion 22 curves in the direction of arrow X. The bending force of the actuator main body portion 22 in the direction of arrow X is determined by the internal pressure of the tube 24.

[0040] The maximum internal pressure of the fluid applied to the tube 24, as determined in the specifications of the fluid pressure actuator 20, is referred to as the "maximum pressure."

[0041] (Deformation of sleeve 26 and thread material W) Fig. 5 shows an enlarged view of the weave of the sleeve 26 before and after bending and deforming the actuator body 22. Note that the two-dot chain line in Fig. 5 indicates the positions of the thread material W of the first group WA and the second group WE when the actuator body 22 is in the initial state.

[0042] 5, even when the actuator body 22 is restored to its original shape after being curved, the intersection point C may move in the direction of the arrow X by a length D. The reason why the intersection point C moves is considered as follows.

[0043] First, when the internal pressure of the tube 24 in the fluid pressure actuator 20 increases, the tube 24 and the sleeve 26 expand in the radial direction R. In other words, the circumferential distance between the intersections C of the thread material W in the sleeve 26 expands.

[0044] However, the fluid pressure actuator 20 according to this embodiment has a restraining member 28 between the tube 24 and the sleeve 26 on the opposite side of the arrow X direction (the right side in FIG. 3), and therefore the sleeve 26 is less likely to expand in the circumferential direction on the opposite side of the arrow X direction. Then, due to the expansion of the sleeve 26 in the radial direction R on the arrow X side, the thread material W in the sleeve 26 tends to move toward the arrow X direction side. Also, if the thread materials W tend to slide against each other at intersection C where the thread materials W cross, apart from the pantograph deformation, the intersection portions of the thread materials W tend to shift, and the intersection C tends to move toward the arrow X direction.

[0045] Therefore, when the sleeve 26 expands in the radial direction R and the circumferential direction, the intersection C between the thread material W of the first group WA and the thread material W of the second group WE tends to move toward the direction of the arrow X in the sleeve 26. In other words, when the fluid pressure actuator 20 is curved and deformed, the intersection C tends to move toward the direction of the arrow X.

[0046] Here, when the inflow of compressed air is stopped and the pressure inside the tube 24 is decreased, the fluid pressure actuator 20 returns to the extended state. The restoring force for the fluid pressure actuator 20 to return from the curved state to the extended state is the force for the restraining member 28 to return from the curved state to the extended state, and the force for the tube 24 to contract in the radial direction R and the circumferential direction due to rubber elasticity. As a result, the arrow X direction side (the left side in the drawing in FIG. 4) of the tube 24 extends in the axial direction S, and the fluid pressure actuator 20 returns to the shape of the extended state.

[0047] On the other hand, regarding the sleeve 26, since the tube 24 extends in the axial direction S, the pantograph-deformed sleeve 26 also contracts in the radial direction R and the circumferential direction. However, since the intersections C of the thread members W of the sleeve 26 are displaced, it is considered that even if a force acts in the direction to cancel the pantograph deformation, it does not completely return to the original crossed position.

[0048] Therefore, as shown in FIG. 5, the sleeve 26 with the intersection C of the thread member W displaced in the arrow X direction is unlikely to return the position of the intersection C to the position in the extended state even if the pressure inside the tube 24 is decreased, and is likely to remain moved by the length D in the arrow X direction from the extended state. And since the intersection C moves in the arrow X direction every time there is a bending deformation, when the bending deformation of the actuator main body 22 is repeated, the amount of movement of the intersection C in the arrow X direction is accumulated.

[0049] In addition, the movement of the intersection C described above occurs at any position within the range of the axial length L0 of the sleeve 26. That is, the fluid pressure actuator 20 becomes a state with a habit, which is difficult to return to the shape extended in the axial direction S by repeating the bending deformation.

[0050] Incidentally, the cross-sectional shapes of the yarn material W before and after the bending deformation of the actuator main body 22, that is, before and after the expansion of the sleeve 26 in the radial direction R, are shown in FIG. 6. In FIG. 6, the arrow θ indicates the extending direction in which the yarn material W, which is the 6A-6A direction in FIG. 4, extends, and is the direction of the arrow θ1 in the yarn material W of the first group WA or the arrow θ2 in the yarn material W of the second group WE. Further, the arrow φ indicates the direction orthogonal to the arrow θ and the arrow R which is the radial direction R of the sleeve 26. In FIGS. 6(A) and 6(B), the diameter X0 is the length of the yarn material W in the direction of the arrow φ in the expanded state, and the diameter Y0 is the length of the yarn material W in the radial direction R in the expanded state. In the present embodiment, in the expanded state, the diameter X0 and the diameter Y0 of the yarn material W are approximately equal, and the cross-section may be regarded as circular.

[0051] First, when the sleeve 26 expands, the yarn material W receives a deformation load from the inside in the radial direction R. In this state, since both ends of the sleeve 26 in the axial direction S are restricted by the caulking member 36, the deformation of the yarn material W in the extending direction is restricted. For this reason, as shown in FIG. 6(A), the yarn material W deforms into a flattened shape as if it is crushed in the radial direction R.

[0052] Then, as shown in FIG. 6, when the sleeve 26 expands in the radial direction R, the major axis length X1, which is the length of the yarn material W in the direction of the arrow φ, becomes longer. That is, when the fluid pressure actuator 20 is in a curved state, the contact area between the yarn materials W that intersect at the intersection C becomes larger. As a result, the pressure at which the yarn materials W contact each other decreases, the yarn materials W easily slide relative to each other, and the intersection C easily moves toward the arrow X.

[0053] Note that the major axis length X1, which is the length of the yarn material W in the direction of the arrow φ after the actuator main body 22 is bent and deformed, is likely to be longer than the diameter X0 in the expanded state. Also, the minor axis length Y1, which is the length of the yarn material W in the radial direction R after the actuator main body 22 is bent and deformed, is likely to be shorter than the diameter Y0 in the expanded state.

[0054] In addition, since the cross-sectional area of the thread material W hardly changes before and after the bending deformation of the actuator main body 22, the cross-section of the thread material W after the actuator main body 22 is bent and deformed can be regarded as an ellipse. Therefore, if the values of the diameter X0 and the diameter Y0 in the stretched state are obtained in advance, the minor axis length Y1 can be obtained by measuring the major axis length X1 after the actuator main body 22 is bent and deformed. That is, for the thread material W after the actuator main body 22 is bent and deformed, by measuring the major axis length X1 of the thread material W from the outside in the radial direction R of the sleeve 26 as shown in Fig. 6(B), the aspect ratio, which is the ratio of the major axis length X1 to the minor axis length Y1 of the thread material W, can be obtained.

[0055] And as described above, when the aspect ratio in the cross-section of the thread material W increases, it can be said that the frictional force between the thread materials W intersecting in the sleeve 26 and between the thread material W and the tube 24 decreases. In other words, when the aspect ratio increases, when the actuator main body 22 is bent and deformed, the intersection point C is likely to shift in the direction of the arrow X, which is the inner side of the bend, and the fluid pressure actuator 20 is likely to develop a habit.

[0056] Note that the major axis length X1 can be said to be the "length in the direction orthogonal to the extending direction and the radial direction of the thread material" in the present embodiment, and the minor axis length Y1 can be said to be the "length in the radial direction" in the present embodiment. Also, the aspect ratio can be said to be the "size of the length in the direction orthogonal to the extending direction and the radial direction of the thread material with respect to the length in the radial direction" in the present embodiment.

[0057] (Conditions for suppressing the movement of the intersection point C) As described above, the state in which the intersection point C is likely to move in the direction of the arrow X is the case where the ratio of the major axis length X1 to the minor axis length Y1 in the cross-section of the thread material W increases when the actuator main body 22 is bent and deformed. The inventors conducted the following various tests to confirm the conditions under which the above-mentioned habit is likely to occur. The conditions and results of each test example conducted by the inventors will be described with reference to Figs. 7 and 8.

[0058] In the following description, the "bending angle" refers to the angle of the fluid pressure actuator 20 after restoration, which is the angle of the fluid pressure actuator 20 deformed from the initial state (the degree of the bend on the fluid pressure actuator 20).

[0059] Also, in each test, when the fluid pressure actuator 20 has repeated 100,000 times of bending deformation, if the bending angle is 30° or less, it is considered to have sufficient performance as a product specification. That is, in each test example, 100,000 times is the target number of bending times.

[0060] [Test 1] In Test 1, the relationship between the number of times of bending deformation when the maximum pressure was applied to the tube 24 and the bending angle after restoration was compared for each aspect ratio of the wire material W when the fluid pressure actuator 20 was bent.

[0061] In this test, the bending angle when the maximum pressure was applied to the tube 24 and the fluid pressure actuator 20 was bent was 90°.

[0062] The specifications of the fluid pressure actuator 20 related to this test are shown below. In the subsequent tests, the fluid pressure actuator 20 used had all conditions other than the sleeve 26 being the same.

[0063]

Table 1

[0064] Also, the conditions related to this test are shown below.

[0065]

Table 2

[0066] And, the relationship between the number of times of bending deformation and the bending angle after restoration measured for the fluid pressure actuator 20 using the sleeve 26 related to Test Example 1 and Test Example 2 is shown in FIG. 7.

[0067] As shown in FIG. 7, it was confirmed by this test that when the ratio of the major axis length X1 to the minor axis length Y1 in the cross section of the thread material W is 4 or less, the movement of the intersection point C in the X direction of the arrow is suppressed. In particular, when the fluid pressure actuator 20 of each test example repeated the bending deformation 100,000 times, which is the target number of bending times, in Test Example 1, the kink angle exceeded 30°, but in Test Example 2, it was 30° or less. Therefore, it can be determined that the performance was improved.

[0068] [Test 2] In Test 2, the relationship between the number of bending deformations at the rated output and the kink angle after recovery was compared for each twist coefficient of the thread material W.

[0069] [Table 3]

[0070] And, FIG. 8 shows the relationship between the number of bending deformations and the kink angle after recovery, which were measured for the fluid pressure actuator 20 using the sleeves 26 according to Test Examples 3 to 6. In this test, although the deviation of the thread material in the sleeve 26 was observed in Test Example 3, the deviation of the thread material was not confirmed in Test Examples 4 to 6.

[0071] As shown in FIG. 8, it was confirmed by this test that when the twist coefficient of the thread material W is 100 or more, the deviation of the thread material due to repeated operation is prevented, and thus the effect of suppressing kinking can be obtained. In particular, when the fluid pressure actuator 20 of each test example repeated the bending deformation 100,000 times, which is the target number of bending times, in Test Example 3, the kink angle exceeded 30°, but in Test Examples 4 to 6, it was 30° or less. Therefore, it can be determined that the performance was improved.

[0072] [Test 3] In Test 3, as Test Example 7, the relationship between the number of times of bending deformation at the rated output and the set angle after recovery was measured using the fluid pressure actuator 20 of Test Example 7 manufactured using a yarn material of 760 dtex, which was thinner than that of Test Example 6. As a result, in the fluid pressure actuator of Test Example 6, the yarn material was worn out and the sleeve was broken before 100,000 operations. In other words, the fluid pressure actuator 20 of Test Example 7 could not achieve the target number of bending deformations, which was 100,000 times.

[0073] From this test, it was confirmed that if the thickness of the yarn material W is 1000 dtex or more, it is possible to obtain the effects of preventing wear and breakage due to the yarn material being too thin and set due to the bias of the yarn material in repeated operations.

[0074] As described above, the embodiments of the present disclosure have been described with reference to the accompanying drawings. However, it is obvious that those having ordinary knowledge in the technical field to which the present disclosure pertains can conceive of various modification examples or application examples within the scope of the technical idea described in the claims, and it is naturally understood that these also belong to the technical scope of the present disclosure.

Explanation of Reference Numerals

[0075] 20 Fluid pressure actuator, 22 Actuator main body part, 24 Tube, 26 Sleeve, 28 Restraining member, 30A First sealing part, 30B Second sealing part, 31 Locking part, 32 First sealing member, 32A Cover part, 32B Insertion part, 33 Second sealing member, 33A Cover part, 34 Locking ring, 36 Caulking member, 38 Mounting part, 38A Mounting hole, W Yarn material, WA First group (an example of a group of yarn materials oriented in one direction), WE Second group (an example of a group of other yarn materials oriented in the other direction), C Intersection point, D Moved length, X1 Major axis length (length in the direction orthogonal to the extending direction and the radial direction of the yarn material), Y1 Minor axis length (length in the radial direction), θ Yarn material extending direction, θ1 First direction (an example of one direction), θ2 Second direction (an example of the other direction), φ Orthogonal direction

Claims

1. A cylindrical tube that expands and contracts in response to the pressure of a fluid, A sleeve that covers the outer peripheral surface of the tube and expands in the radial direction while restricting the axial elongation of the tube due to the expansion of the tube, A plate-like restraining member provided on the inner side in the radial direction of the sleeve, extending from one side to the other side in the axial direction, resisting compression along the axial direction, and deformable in a crossing direction that intersects the axial direction, A pair of sealing members that seal the ends on one side and the other side in the axial direction of the tube, respectively, and have an insertion portion into which the tube is inserted, A fluid pressure actuator comprising: The sleeve has a group of yarns oriented in one direction and another group of yarns oriented in another direction that intersects the group of yarns, and the respective yarns in the group of yarns and the other group of yarns are alternately intertwined to form, Each of the yarns has a length in a direction orthogonal to the extending direction of the yarn and the radial direction that is four times or less the length in the radial direction when the pressure of the fluid applied to the tube is maximum. Fluid pressure actuator.

2. The yarn has a twist coefficient of 100 or more. The fluid pressure actuator according to Claim 1.

3. The yarn has a thickness of 1000 dtex or more. The fluid pressure actuator according to Claim 1 or Claim 2.

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