Fluid pressure actuator

Abstract

A fluid pressure actuator is provided with: a cylindrical tube that expands and contracts in accordance with the pressure of a fluid; a sleeve that covers the outer peripheral surface of the tube, restricts the extension of the tube in the axial direction (S) due to the expansion of the tube, and permits the expansion of the tube in the radial direction due to the expansion of the tube; a restraining member that is provided on the inside in the radial direction of the sleeve from one side to the other side in the axial direction (S), is capable of resisting compression in the axial direction, and is capable of deforming in an intersecting direction (X) intersecting the axial direction; a first seal member and a second seal member that seal one end and the other end of the tube in the axial direction (S), respectively; and a positioning member that is provided in a portion of at least one of the first seal member and the second seal member in the circumferential direction, and that positions the restraining member in the axial direction.

Description

Technical Field

[0001] The present disclosure relates to fluid pressure actuators. Background Art

[0002] Japanese Patent Application Laid-Open No. 2021-088999 discloses a fluid pressure actuator including a cylindrical tube that expands and contracts due to the pressure of a fluid and a stretchable structure in which fiber cords oriented in a predetermined direction are knitted.

[0003] The fluid pressure actuator is a fluid pressure actuator comprising a sleeve covering the outer peripheral surface of a tube and a sealing member sealing the axial end of the tube, wherein the fluid pressure actuator comprises a restraining member arranged on the inner side of the sleeve from one axial end side to the other end side, the restraining member being capable of resisting compression along the axial direction and being capable of deforming in an orthogonal direction to the axial direction. Summary of the invention

[0004] Problem that the invention aims to solve

[0005] In the structure described in Japanese Patent Application Laid-Open No. 2021-088999, it is difficult to align the extending direction of the restraint member and the axial direction of the pipe when assembling the fluid pressure actuator.

[0006] An object of the present disclosure is to provide a fluid pressure actuator that can easily extend a restricting member in the axial direction of a pipe.

[0007] Solutions for solving problems

[0008] The fluid pressure actuator of the first technical solution comprises: a cylindrical tube that expands and contracts according to the pressure of the fluid; a sleeve that covers the outer circumferential surface of the tube, limits the axial elongation of the tube due to the expansion of the tube and allows the tube to expand radially due to the expansion of the tube; a restraining member that is arranged on the radial inner side of the sleeve from one side to the other side in the axial direction, can resist compression along the axial direction, and can be deformed in a cross direction intersecting the axial direction; a pair of sealing members that respectively seal the ends of one side and the other side of the tube in the axial direction; and a positioning member that is arranged in a circumferential portion of at least one of the pair of sealing members to position the restraining member in a manner along the axial direction.

[0009] According to this fluid pressure actuator, since the sealing member on at least one side in the axial direction is provided with the positioning member for positioning the restraining member along the axial direction, it is easy to assemble the fluid pressure actuator so that the restraining member is along the axial direction.

[0010] In the fluid pressure actuator according to a second aspect, in the fluid pressure actuator according to the first aspect, the positioning member is located on one side in the axial direction relative to the end portion of the tube.

[0011] According to this fluid pressure actuator, the positioning member is located axially further to one side than the end of the tube. Therefore, when assembling the fluid pressure actuator, a hole is formed in the end of the tube without interfering with the positioning member, and the restraining member can be easily positioned.

[0012] In the fluid pressure actuator of the third technical solution, according to the fluid pressure actuator described in the first technical solution or the second technical solution, the positioning member is a pair of protrusions that arrange the restraining member in the middle to restrict the movement of the restraining member in the circumferential direction of the sealing member.

[0013] According to this fluid pressure actuator, the positioning member can be easily formed by providing the protrusion on the sealing member.

[0014] In the fluid pressure actuator of a fourth aspect, in the fluid pressure actuator according to any one of the first to third aspects, the positioning member has a second protrusion that restricts movement of the restricting member in the axial direction of the sealing member.

[0015] According to this fluid pressure actuator, since the second protrusion that restricts the movement of the restraining member in the axial direction is provided, it is easier to assemble the fluid pressure actuator so that the restraining member is along the axial direction than in a case without the second protrusion.

[0016] In the fluid pressure actuator of the fifth technical solution, the fluid pressure actuator according to any one of the first technical solution to the fourth technical solution, wherein the sealing member has an insertion portion inserted into the end portion of the tube, and the fluid pressure actuator also has a crimping member that crimps the tube, the sleeve and the restraint member to the sealing member from the radially outer side in the range from the positioning member to the insertion portion.

[0017] According to this fluid pressure actuator, the restraining member can be fixed by pressure-bonding together with the tube and the collar.

[0018] In the fluid pressure actuator according to a sixth aspect, according to the fluid pressure actuator according to any one of the first to fifth aspects, the positioning member is provided on both of the pair of sealing members.

[0019] According to the fluid pressure actuator, a sealing member at one end side in the axial direction and a sealing member at the other end side are provided with a positioning member for positioning the constraint member in an axial manner, thereby obtaining a fluid pressure actuator that can easily make the extension direction of the constraint member along the axial direction of the tube in a state where the torsion of the tube is eliminated.

[0020] Effects of the Invention

[0021] According to the present disclosure, it is possible to provide a fluid pressure actuator that can easily make the extending direction of the restraint member along the axial direction of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a plan view of the fluid pressure actuator according to the first embodiment of the present disclosure.

[0023] Figure 2 This is an exploded perspective view of one end side in the axial direction of the fluid pressure actuator according to the first embodiment of the present disclosure.

[0024] Figure 3 It is a perspective view illustrating a sealing member according to a first embodiment of the present disclosure.

[0025] Figure 4 It is a plan view illustrating a sealing member according to a first embodiment of the present disclosure.

[0026] Figure 5 It is a cross-sectional view for explaining the operation of the fluid pressure actuator according to the first embodiment of the present disclosure.

[0027] Figure 6 It is a perspective view illustrating a sealing member according to a second embodiment of the present disclosure.

[0028] Figure 7 It is a plan view illustrating a sealing member according to a second embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments for realizing the technology of the present disclosure will be described in detail with reference to the drawings.

[0030] In addition, for components and processes that play the same role and function, the same reference numerals are marked in all drawings, and repeated descriptions are sometimes appropriately omitted. In addition, the present disclosure is not limited to the following embodiments, and can be appropriately modified and implemented within the scope of the purpose of the present disclosure.

[0031] [First embodiment]

[0032] <Structure of Fluid Pressure Actuator 20>

[0033] Figure 1 A fluid pressure actuator 20 according to a first embodiment of the present disclosure is shown. The fluid pressure actuator 20 includes an actuator body 22, a first sealing member 30A, and a second sealing member 30B.

[0034] Also like Figure 2As shown, the actuator body 22 has a tube 24, a sleeve 26 and a restraining member 28. The tube 24 is cylindrical and can be expanded and contracted based on elastic deformation, and expands and contracts due to changes in the pressure of the internal fluid. The axial direction S of the tube 24 is set to "axial direction S". The tube 24 can be made of elastic materials such as butyl rubber. As the fluid supplied to the tube 24, air can be used. In this case, the fluid pressure actuator 20 becomes a pneumatic actuator. In addition, when the fluid pressure actuator 20 is hydraulically driven, it is preferably set to at least one selected from the group consisting of NBR (nitrile rubber) with higher oil resistance, hydrogenated NBR, chloroprene rubber and chloroether rubber.

[0035] The sleeve 26 is cylindrical and covers the outer circumference of the tube 24. The sleeve 26 is a stretchable structure obtained by weaving fiber cords oriented in a predetermined direction, and the oriented cords cross at a predetermined angle θ relative to the axial direction S. The sleeve 26 has such a shape, so that it can be scaled and deformed to change the angle θ, restrict the contraction and expansion of the tube 24, and follow the contraction and expansion.

[0036] Aromatic polyamide (aramid fiber) or polyethylene terephthalate (PET) fiber cords are preferably used as the cords constituting the sleeve 26. However, the fiber cords are not limited to such types, and other high-strength fiber cords such as PBO fiber (polyparaphenylene benzobisoxazole) may be used.

[0037] The restraining member 28 is provided between the tube 24 and the sleeve 26. The restraining member 28 is in the shape of an elongated plate, and its length direction is arranged along the axial direction S of the tube 24, and covers a part of the outer circumference of the tube 24, and is arranged from one end of the tube 24 to the other end.

[0038] The restraining member 28 is formed of a material that does not expand or contract due to pressure, and can bend and deform in a direction in which the ends approach each other. As the restraining member 28, a so-called leaf spring can be used. The size of the leaf spring is determined by the size of the fluid pressure actuator 20, the required holding force, etc. In addition, the material of the leaf spring is not particularly limited. Typically, it can be a material that is easy to bend and deform and resistant to compression, such as metals such as stainless steel. In addition, it can also be formed by a thin plate of carbon fiber reinforced plastic (CFRP), etc.

[0039] The first sealing member 30A includes a sealing connector 32 , a locking ring 34 , and a crimping member 36 .

[0040] The sealing connector 32 has an integrally formed cover 32A and an insertion portion 32B. The cover 32A is a roughly rectangular parallelepiped shape with a larger diameter than the outer diameter of the tube 24, and the insertion portion 32B is formed to extend from the center of one end side of the cover 32A along the axial direction S. The insertion portion 32B has a locking portion 48 and a large diameter portion 50, which is a so-called bamboo shoot shape and is inserted into one end side of the tube 24 on the inner side of the sleeve 26. The locking portion 48 is a cylindrical portion with a reduced diameter compared to the cover 32A and the insertion portion 32B on the other end side of the axial direction S of the insertion portion 32B. The large diameter portion 50 is a portion with a positioning member on one end side of the axial direction S of the locking portion 48 compared to the inner diameter of the locking portion 48 and the tube 24. As the first sealing member 30A, it is suitable to use metals such as stainless steel, but it is not limited to such metals, and hard plastic materials, etc. can also be used. In addition, about the positioning member, it will be described later.

[0041] In addition, the insertion portion 32B has a flow path R (see also FIG. 1 ) formed in the radial center portion thereof so as to extend in the axial direction S and communicate with the connection hole H on the side surface of the cover portion 32A. Figure 5 An air supply hose (not shown) is connected to the connection hole H to supply compressed air to the flow path R.

[0042] The locking ring 34 is annular and is disposed outside the sleeve 26 so as to sandwich the sleeve 26 with the locking portion 48, locking the sleeve 26 to the sealed connector 32. The sleeve 26 is folded toward the outer periphery via the locking ring 34. The locking ring 34 can be made of metal, hard plastic, fiber, rubber, or other materials.

[0043] The crimping member 36 is arranged on the outer periphery of the actuator body 22 so as to cover the portion into which the insertion portion 32B is inserted, and crimps the actuator body 22 to the sealed connector 32. Thus, the actuator body 22 is fixed to the sealed connector 32. As the crimping member 36, a metal such as aluminum alloy, brass, and iron can be used.

[0044] In this embodiment, if Figure 2 to Figure 4 As shown, the positioning member is a pair of first protrusions 44 and second protrusions 46 protruding from the large diameter portion 50 of the insertion portion 32B. In the present embodiment, the first protrusions 44 and second protrusions 46 align the restraining member 28 in such a manner that the plate surface of the restraining member 28 and the surface of the sealing connector 32 where the connection hole H is formed face the same direction.

[0045] like Figure 3 and Figure 4As shown, the pair of first protrusions 44 are protruding portions that protrude radially outward from one side (insertion portion 32B side) in the axial direction S of the large diameter portion 50 and are formed opposite to each other at a distance W slightly wider than the width of the restraining member 28 in the circumferential direction. In addition, the "slightly wider distance" is a distance that allows for a clearance fit with the restraining member 28 as described later, and the specific size is appropriately designed according to the width of the restraining member 28.

[0046] like Figure 3 and Figure 4 As shown, the second protrusion 46 is a protrusion-shaped portion that protrudes outward from one side (the cover portion 32A side) in the axial direction S of the large diameter portion 50 and is formed between the pair of first protrusions 44 in the circumferential direction.

[0047] In addition, in the present embodiment, the end of the pipe 24 inserted into the insertion portion 32B can abut against the step 42 on one side of the large diameter portion 50 in the axial direction S as described later.

[0048] In addition, in this embodiment, if Figure 3 and Figure 4 As shown, the first protrusion 44 and the second protrusion 46 are formed at four locations in total at intervals of approximately 90° in the circumferential direction of the large diameter portion 50. As described later, the positions and numbers of the plurality of first protrusions 44 and second protrusions 46 formed in the circumferential direction are appropriately designed together with the restraining member 28.

[0049] The second sealing member 30B includes a sealing connector 33, a locking ring 34, and a crimping member 36. The sealing connector 33 is the same as the sealing connector 32 of the first sealing member 30A except that the connection hole H and the flow path R are not formed and the tip is R-shaped.

[0050] Next, the assembly procedure of the fluid pressure actuator 20 in this embodiment will be described.

[0051] <Assembly of Fluid Pressure Actuator 20>

[0052] like Figure 2 and Figure 5 As shown in FIG. 1 , at one end side of the fluid pressure actuator 20 in the present embodiment, the first sealing member 30A and the actuator body 22 are assembled as follows.

[0053] First, the insertion portion 32B of the first sealing member 30A is inserted until one end of the tube 24 abuts against the step 42. Next, the restraining member 28 abuts against the second protrusion 46 and is disposed between the pair of first protrusions 44 ( Figure 2As a result, the restraining member 28 contacts both sides of the pair of first protrusions 44 in the circumferential direction and is restricted in circumferential movement by the pair of first protrusions 44, and is restricted in movement to one side in the axial direction S (the cover portion 32A side) by the second protrusion 46. In other words, the pair of first protrusions 44 position the restraining member 28 in a manner along the axial direction S. In addition, as described later, the circumferential position of the restraining member 28 is arranged to be outside the direction in which the actuator body 22 is bent (the direction orthogonal to the axial direction S).

[0054] Next, the sleeve 26 is placed over the tube 24 and the cover portion 32A of the first sealing member 30A to cover the outer peripheral surface of the restraint member 28 , and the locking ring 34 is installed at the locking portion 48 from the radially outer side of the sleeve 26 , thereby locking the sleeve 26 to the locking portion 48 .

[0055] Next, the sleeve 26 is folded to the insertion portion 32B of the first sealing member 30A so that the locking ring 34 is on the inner side, and the crimping member 36 is arranged from the radially outer side of the sleeve 26 to span the insertion portion 32B and the locking portion 48, and crimped using a crimping machine (not shown). Thus, the tube 24, the restraining member 28, and the sleeve 26 are fixed to the first sealing member 30A on one side in the axial direction S of the actuator body 22.

[0056] Next, on the other side of the tube 24 , the sleeve 26 , and the restraining member 28 in the axial direction S, the restraining member 28 is passed between the first protrusions 44 of the large diameter portion 50 of the second sealing member 30B and abuts against the second protrusions 46 .

[0057] Next, the insertion portion 32B of the second sealing member 30B is inserted toward the other side in the axial direction S of the tube 24 while being careful not to let the restraining member 28 slip out from between the first protrusions 44 of the second sealing member 30B.

[0058] Next, the sleeve 26 is placed over the tube 24 and the cover portion 32A of the second sealing member 30B to cover the outer peripheral surface of the restraint member 28 , and the locking ring 34 is installed at the locking portion 48 from the radially outer side of the sleeve 26 , thereby locking the sleeve 26 to the locking portion 48 .

[0059] Next, the sleeve 26 is folded to the insertion portion 32B of the second sealing member 30B so that the locking ring 34 is on the inner side, and the crimping member 36 is arranged from the radially outer side of the sleeve 26 to span the insertion portion 32B and the locking portion 48, and crimped using a crimping machine (not shown). Thus, the tube 24, the restraining member 28, and the sleeve 26 are fixed to the second sealing member 30B on the other side of the actuator body 22 in the axial direction S.

[0060] Through the above steps, one side and the other side of the tube 24 are sealed by the first sealing member 30A and the second sealing member 30B, and the fluid pressure actuator 20 is assembled.

[0061] Next, the operation of the fluid pressure actuator 20 in the present disclosure will be described.

[0062] <Operation of Fluid Pressure Actuator 20>

[0063] like Figure 5 As shown, the fluid pressure actuator 20 is used in a manner in which the first sealing member 30A on one end side is fixed and the second sealing member 30B on the other end side is a free end.

[0064] If compressed air is allowed to flow in from the connection hole H, the pressure in the fluid pressure actuator 20 rises. As the internal pressure rises, the tube 24 elastically deforms and expands, and the sleeve 26 is deformed in a scaling manner so that the angle θ becomes larger, and a force is applied in the direction of shortening the length of the actuator body 22. At this time, the outer peripheral side wall of the actuator body 22 where the restraining member 28 is arranged is restricted from shortening, so that the outer peripheral wall of the actuator body 22 on the side where the restraining member 28 is not arranged when viewed from the axial direction S is shortened. As a result, the restraining member 28 is flexed and deformed, as shown in FIG. Figure 5 As shown by the two-dot chain line in FIG. 8 , the actuator body 22 is bent as a whole.

[0065] In addition, in the present disclosure, the restraining member 28 has a length in the width direction, and therefore is not easily bent in directions other than the plate thickness direction, that is, the direction intersecting the axial direction S of the first sealing member 30A and the second sealing member 30B (hereinafter referred to as the "intersecting direction X"). Figure 5 As shown, the restraining member 28 is bent in a direction toward the axial center of the tube 24 .

[0066] Next, the operation and effects achieved by the fluid pressure actuator 20 of the present disclosure will be described.

[0067] <Function and Effect>

[0068] The fluid pressure actuator 20 of the present disclosure has the first protrusion 44 for positioning the restraint member 28 along the axial direction S on at least one of the first sealing member 30A and the second sealing member 30B. Therefore, the fluid pressure actuator 20 can be easily assembled with the restraint member 28 along the axial direction S.

[0069] In addition, according to the fluid pressure actuator 20 in the present disclosure, the first protrusion 44 is located on the side closer to the axial direction S than the end of the tube 24, so when assembling the fluid pressure actuator 20, the end of the tube 24 and the positioning member will not interfere with each other, and the restraint member 28 can be easily positioned.

[0070] Furthermore, according to the fluid pressure actuator 20 in the present disclosure, the positioning member can be easily formed by providing the first protrusion 44 on the first sealing member 30A and the second sealing member 30B.

[0071] Furthermore, according to the fluid pressure actuator 20 of the present disclosure, the second protrusion 46 that restricts the movement of the restraining member 28 in the axial direction S is also provided, so that the fluid pressure actuator 20 is easier to assemble with the restraining member 28 along the axial direction S than when the second protrusion 46 is not provided.

[0072] Furthermore, according to the fluid pressure actuator 20 of the present disclosure, the restraining member 28 can be fixed by being crimped together with the tube 24 and the sleeve 26 .

[0073] In addition, according to the fluid pressure actuator 20 in the present disclosure, the first sealing member 30A on one end side in the axial direction S and the second sealing member 30B on the other end side are provided with a first protrusion 44 for positioning the restraint member 28 in a manner along the axial direction S, thereby making it easy to obtain a fluid pressure actuator 20 in which the extension direction of the restraint member 28 is along the axial direction S of the tube 24 in a state in which the torsion of the tube 24 is eliminated.

[0074] [Second embodiment]

[0075] Next, a second embodiment will be described. In this embodiment, the same reference numerals are used for the same parts as those in the first embodiment, and detailed description thereof will be omitted.

[0076] Figure 6 and Figure 7 2 is a diagram showing a sealed connector 32 according to a second embodiment of the present disclosure. Figure 6 and Figure 7 As shown in FIG. 1 , a groove 54 is formed in the large diameter portion 50 of the sealed connector 32 along the axial direction S. Figure 6 and Figure 7 As shown, as an example, the grooves 54 are formed at four locations at equal intervals in the circumferential direction.

[0077] The width W of the groove 54 is slightly wider than the width of the restraining member 28, so that the restraining member 28 can be arranged in the middle inside the groove 54. Therefore, the circumferential wall portion 54A, which is the wall portion facing each other in the circumferential direction of the groove 54, has the same function as the first protrusion 44 of the first embodiment. In addition, the length of the groove 54 in the axial direction S is appropriately designed so that the movement of the restraining member 28 in the circumferential direction can be restricted in the state where the restraining member 28 is sandwiched in the middle.

[0078] In addition, a portion of the groove 54 on one side in the axial direction S is a shaft side wall portion 54B that can be abutted by the restraining member 28. Therefore, the shaft side wall portion 54B has the same function as the first protrusion 44 of the first embodiment.

[0079] In addition, if Figure 6 and Figure 7 As shown, the bottom portion of the groove 54, that is, the groove bottom 54C is substantially flat. Therefore, when the restraint member 28 is arranged in the groove 54, a gap is unlikely to be generated between the groove bottom 54C and the back surface (radially inner surface) of the restraint member 28.

[0080] As described above, also in this embodiment, the same operations and effects as those of the fluid pressure actuator 20 of the first embodiment can be obtained.

[0081] <Modification>

[0082] In addition, in the above description, the second sealing member 30B has a positioning member, but the fluid pressure actuator 20 of the present disclosure is not limited to this. That is, it is also possible to configure that any one of the first sealing member 30A and the second sealing member 30B does not have a positioning member. In this case, the other of the first sealing member 30A and the second sealing member 30B has a positioning member, so it is also possible to obtain a fluid pressure actuator 20 that can easily make the extension direction of the restraining member 28 along the axial direction S of the pipe 24.

[0083] In addition, in the above description, the positioning member is crimped together with the sleeve 26 and the tube 24 by the crimping member 36, but the fluid pressure actuator 20 of the present disclosure is not limited to this. That is, the positioning member may be configured not to be crimped together with the sleeve 26 and the tube 24. In this case, the fluid pressure actuator 20 can be easily obtained so that the extension direction of the restraining member 28 is along the axial direction S of the tube 24.

[0084] In the above description, the positioning member has the second protrusion 46, but the fluid pressure actuator 20 of the present disclosure is not limited thereto, and the positioning member may be configured not to have the second protrusion 46. In this case, the fluid pressure actuator 20 can be easily configured to extend the restraining member 28 along the axial direction S of the tube 24.

[0085] In addition, in the above description, the positioning member is formed with a pair of first protrusions 44 that limit the movement of the constraint member 28 in the circumferential direction of the first sealing member 30A or the second sealing member 30B by placing the constraint member 28 in the middle, but the fluid pressure actuator 20 of the present disclosure is not limited to this. That is, the positioning member may also be a structure with a shape different from the first protrusion 44 of the present disclosure. For example, it may also be configured so that the positioning member is a pin protruding in the radial direction, and a hole is opened in the constraint member 28, and the movement of the constraint member 28 in the circumferential direction is limited by engaging the hole and the pin. In this case, it is also possible to obtain a fluid pressure actuator 20 that can easily make the extension direction of the constraint member 28 along the axial direction S of the tube 24.

[0086] In addition, in the above description, the positioning member is formed at a position closer to the side of the axial direction S than the end of the tube 24, but the fluid pressure actuator 20 of the present disclosure is not limited to this, and the positioning member may overlap with the end of the tube 24 on the one side in the axial direction S. For example, a hole may be provided at the end of the tube 24 on the one side in the axial direction S, so that the first protrusion 44 of the positioning member passes through the hole, thereby forming a shape in which the tube 24 and the positioning member do not interfere with each other. In this case, it is also possible to obtain a fluid pressure actuator 20 that can easily make the extension direction of the restraint member 28 along the axial direction S of the tube 24.

[0087] The above, while referring to the attached Figure 1 While explaining the embodiments of the present disclosure, it is obvious that a person having common knowledge in the technical field to which the present disclosure belongs can think of various modification examples or application examples within the scope of the technical idea described in the claims, and it should be understood that these modification examples or application examples certainly also belong to the technical scope of the present disclosure.

[0088] The disclosure of Japanese Patent Application No. 2022-162679 filed on October 7, 2022 is incorporated herein by reference in its entirety.

[0089] All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A fluid pressure actuator comprising: A cylindrical tube that expands and contracts according to the pressure of the fluid; a sleeve covering the outer circumferential surface of the tube, limiting the axial elongation of the tube due to the expansion of the tube and allowing the tube to expand in the radial direction due to the expansion of the tube; a restraining member, which is arranged on the inner side of the sleeve in the radial direction from one side to the other side in the axial direction, can resist compression along the axial direction, and can be deformed in a direction intersecting the axial direction; a pair of sealing members for respectively sealing the ends on one side and the other side in the axial direction of the tube; and A positioning member is provided at a portion of at least one of the pair of sealing members in the circumferential direction and positions the restraining member along the axial direction.

2. The fluid pressure actuator according to claim 1, wherein: The positioning member is located on one side in the axial direction relative to the end portion of the pipe.

3. The fluid pressure actuator according to claim 1, wherein: The positioning member is a pair of protrusions that restrict movement of the restricting member in the circumferential direction of the sealing member by placing the restricting member in the middle.

4. The fluid pressure actuator according to claim 1, wherein: The positioning member has a second protrusion that restricts movement of the regulating member in the axial direction of the sealing member.

5. The fluid pressure actuator according to claim 1, wherein: The sealing member has an insertion portion inserted into an end portion of the tube, The fluid pressure actuator further includes a pressing member that presses the tube, the sleeve, and the restraining member against the sealing member from the outside in the radial direction in a range from the positioning member to the insertion portion.

6. The fluid pressure actuator according to any one of claims 1 to 5, wherein: The positioning member is provided on both of the pair of sealing members.

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