Hydraulic actuator

Abstract

A fluid pressure actuator 20 includes: a sealing member 30 in which is formed an insertion part 50 pair having a pair of insertion parts 50 into which end parts along an axial direction X of a tube 24 of a tube 24 pair are respectively inserted, said sealing member 30 sealing the end parts of the tubes 24; and a restraint member 28 which is provided from one end side to the other end side of the tube 24 pair in the axial direction X, and is held between opposing parts of the respective tubes 24 where the tubes face each other. For each of the insertion parts 50, the length in a width direction Y orthogonal to an alignment direction Z, in which the insertion parts 50 are aligned as viewed from the axial direction X, is greater than the length in the alignment direction Z.

Description

Fluid Pressure Actuator

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

[0002] Japanese Patent Application Laid-Open Publication No. 2021-088998 discloses a fluid pressure actuator that includes a cylindrical tube that expands and contracts due to fluid pressure, an elastic structure made of woven fiber cords oriented in a predetermined direction, a sleeve that covers the outer surface of the tube, and a sealing member that seals the axial end of the tube, wherein the tubes are arranged in a line perpendicular to the axial direction, and at the opposing portions where adjacent tubes face each other, a restraining member is provided that extends from one axial end of the tube to the other axial end, and the restraining member resists compression along the axial direction and is deformable in the orthogonal direction.

[0003] In the configuration described in JP 2021-088998 A, the sealing member of the fluid pressure actuator has a large length in the arrangement direction, which is the direction in which the pair of tubes are arranged.

[0004] An object of the present disclosure is to provide a fluid pressure actuator in which the length of a sealing member in the arrangement direction, that is, the direction in which a pair of tubes are arranged, is reduced.

[0005] A first aspect of the fluid pressure actuator comprises a tube pair having a pair of tubes aligned in parallel that expand and contract due to fluid pressure, a sleeve covering the outer surfaces of the pair of tubes and expanding the tubes radially while restricting axial extension as the tubes expand, a pair of insertion parts having a pair of insertion parts into which axial ends of the tubes of the pair of tubes are respectively inserted, a sealing member sealing the ends of each of the tubes, and a restraint member extending from one axial end side to the other axial end side of the pair of tubes and sandwiched between opposing portions where the tubes face each other, and each of the insertion parts has a length in a width direction perpendicular to the arrangement direction in which the insertion parts are arranged when viewed from the axial direction that is longer than the length in the arrangement direction.

[0006] In the fluid pressure actuator according to this aspect, the length of each of the insertion sections in the width direction is longer than the length in the arrangement direction, which allows the cross-sectional area of ​​the tube inserted into the insertion section to be larger than when the lengths of the insertion sections in the arrangement direction and the width direction are equal.

[0007] A fluid pressure actuator of a second aspect is the fluid pressure actuator according to the first aspect, wherein the pair of insertion portions has an oval shape.

[0008] In the fluid pressure actuator according to this aspect, the shape of the insertion portion is an ellipse that is long in the width direction. Therefore, with the fluid pressure actuator according to this aspect, the manufacturing cost of the sealing member can be reduced compared to when the shape of the pair of insertion portions is not an ellipse that is long in the width direction.

[0009] The fluid pressure actuator of the third aspect is the fluid pressure actuator described in the first or second aspect, wherein the sealing member has a base end portion on the outside in the axial direction that is larger in diameter than the pair of insertion portions, and the end portion of the restraint member in the axial direction is inserted into an insertion portion formed in the base end portion.

[0010] In the fluid pressure actuator according to this aspect, the end of the restraining member is inserted into the insertion portion axially outside the pair of insertion portions, so that the restraining member is less likely to become displaced after the fluid pressure actuator is assembled.

[0011] A fluid pressure actuator of a fourth aspect is a fluid pressure actuator described in any one of the first to third aspects, wherein the sealing member is divided into a first sealing member in which one of the insertion portions is formed and a second sealing member in which the other of the insertion portions is formed, and the first sealing member and the second sealing member are formed by overlapping each other in the alignment direction.

[0012] In the fluid pressure actuator according to this aspect, an insertion portion is formed in each of the first sealing member and the second sealing member, and the sealing portion is formed by overlapping the first sealing member and the second sealing member. As a result, with the fluid pressure actuator according to this aspect, the manufacturing cost of the sealing member can be reduced compared to when the sealing member is formed from a single piece of material.

[0013] A fluid pressure actuator of a fifth aspect is the fluid pressure actuator according to the fourth aspect, wherein the first sealing member and the second sealing member have the same shape across a dividing surface.

[0014] In the fluid pressure actuator according to this aspect, the first sealing member and the second sealing member have the same shape on either side of the dividing surface, which reduces the number of types of parts in the fluid pressure actuator, and therefore the manufacturing cost of the sealing members can be reduced compared to when the first sealing member and the second sealing member have different shapes.

[0015] The fluid pressure actuator of the sixth aspect is the fluid pressure actuator of the fourth or fifth aspect, wherein when the first sealing member and the second sealing member are stacked in the alignment direction, a plurality of fitting portions are formed on the dividing surfaces, which position the first sealing member and the second sealing member by fitting a boss portion into a recess portion.

[0016] In the fluid pressure actuator according to this aspect, a plurality of fitting portions are formed on the dividing surfaces, and the fitting portions position the first sealing member and the second sealing member by fitting a boss portion into a recess portion that fits together when the first sealing member and the second sealing member are overlapped. This allows the first sealing member and the second sealing member to be overlapped with high precision.

[0017] According to the present disclosure, a fluid pressure actuator is provided in which the length of a sealing member in the fluid pressure actuator in the arrangement direction, which is the direction in which a pair of tubes are arranged, is reduced.

[0018] FIG. 1 is a plan view of a fluid pressure actuator according to an embodiment of the present disclosure; FIG. 2 is an exploded perspective view of one axial end side of a fluid pressure actuator according to an embodiment of the present disclosure; FIG. 3 is a perspective view illustrating a front side of a first sealing member according to an embodiment of the present disclosure; FIG. 4 is a perspective view illustrating a back side of a first sealing member according to an embodiment of the present disclosure; FIG. 5 is a plan view illustrating a first sealing member according to an embodiment of the present disclosure; FIG. 6 is a side view illustrating a sealing member according to an embodiment of the present disclosure; FIG. 7 is a front view illustrating a sealing member according to an embodiment of the present disclosure; and FIG. 8 is a cross-sectional view illustrating operation of a fluid pressure actuator according to an embodiment of the present disclosure.

[0019] Hereinafter, embodiments for realizing the technology of the present disclosure will be described in detail with reference to the drawings.

[0020] In addition, components and processes that perform the same actions and functions are given the same reference numerals throughout the drawings, and duplicated explanations may be omitted as appropriate. Furthermore, the present disclosure is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the purpose of the present disclosure.

[0021] Note that the "arrow Z+ direction" and "arrow Z- direction" in each drawing are examples of the axial direction X in the present disclosure. Also, the "arrow Y+ direction" and "arrow Y- direction" in each drawing are examples of one of the alignment directions Z in the present disclosure. Also, the "arrow X+ direction" and "arrow X- direction" in each drawing are examples of the width direction Y in the present disclosure.

[0022] In the following description, "one side" refers to the "+" side of the arrows X, Y, and Z, and "the other side" refers to the "-" side of the arrows X, Y, and Z. In other words, when the axial direction X, the arrangement direction Z, and the width direction Y are described without adding "one side" or "the other side," they may refer to both the "+" side and the "-" side.

[0023] 1 shows a fluid pressure actuator 20 according to an embodiment of the present disclosure. The fluid pressure actuator 20 includes an actuator body 22, a sealing member 30, and a sealing member 31.

[0024] As also shown in FIG. 2, the actuator body 22 includes a pair of tubes 24, a sleeve 26, a restraining member 28, a locking ring 34, and a crimping member 36.

[0025] The tubes 24 are cylindrical members that can expand and contract due to elastic deformation, and expand and contract due to pressure changes of the fluid inside. Note that, when the fluid pressure actuator 20 is in an assembled state, the longitudinal direction of the tubes 24 coincides with the axial direction X. Furthermore, as shown in FIG. 2, when the fluid pressure actuator 20 is in an assembled state, the tubes 24 are arranged in parallel.

[0026] The tube 24 can be made of an elastic material such as butyl rubber. Air can be used as the fluid supplied to the tube 24, in which case the fluid pressure actuator 20 becomes a pneumatic actuator. If the fluid pressure actuator 20 is hydraulically driven, it is preferable to use at least one material selected from the group consisting of highly oil-resistant NBR (nitrile rubber), hydrogenated NBR, chloroprene rubber, and epichlorohydrin rubber.

[0027] The sleeve 26 is a cylindrical member that covers the outer periphery of the tube 24. The sleeve 26 is an elastic structure made by weaving fiber cords oriented in a predetermined direction, and the oriented cords intersect at a predetermined angle θ with respect to the axial direction X. By having such a shape, the sleeve 26 undergoes pantograph deformation that changes the angle θ, and follows the contraction and expansion of the tube 24 while regulating this contraction and expansion.

[0028] It is preferable to use fiber cords made of aromatic polyamide (aramid fiber) or polyethylene terephthalate (PET) as the cords constituting the sleeve 26. However, the cords are not limited to these types of fiber cords, and other high-strength fiber cords such as PBO fiber (polyparaphenylene benzobisoxazole) may also be used.

[0029] The restraining member 28 is provided between the pair of tubes 24. The restraining member 28 is in the form of a long plate, and is arranged so that its longitudinal direction is along the axial direction X of the tube 24, and is arranged from one end to the other end of the tube 24 while contacting part of the outer periphery of the tube 24. More specifically, as shown in Fig. 8 described below, the restraining member 28 is sandwiched between the opposing portions of the pair of tubes 24 when the fluid pressure actuator 20 is assembled.

[0030] The restraining member 28 is formed of a material that does not expand or contract when pressurized, and is capable of bending and deforming in the direction in which its ends approach each other. A so-called leaf spring can be used as the restraining member 28. The dimensions of the leaf spring are determined based on the magnitude of the force that bends and deforms the actuator body 22, as required by the size and specifications of the fluid pressure actuator 20 (see also FIG. 8 ). The material of the leaf spring is not particularly limited, but typically, any material that is easily bendable and resistant to compression, such as a metal such as stainless steel, may be used. Alternatively, the leaf spring may be formed of a thin plate of carbon fiber reinforced plastic (CFRP).

[0031] The locking ring 34 is a ring-shaped member that is disposed on the outside of the sleeve 26 so as to sandwich the sleeve 26 between itself and a locking portion 58 (described later), and locks the sleeve 26 to the semi-proximal end portion 40. As a result, the sleeve 26 is folded back to the outer periphery via the locking ring 34. The locking ring 34 may be made of a material such as metal, hard plastic, fiber, or rubber.

[0032] The crimping member 36 is disposed so as to cover the outer periphery of the actuator body 22 where the insertion portion 50 is inserted, and presses the actuator body 22 against the insertion portion 50, which will be described later. This fixes the actuator body 22 to the insertion portion 50 of the sealing member 30, which will be described later. The crimping member 36 can be made of a metal such as aluminum alloy, brass, or iron.

[0033] 3 to 7, the sealing member 30 has a first sealing member 30A and a second sealing member 30B that are separated in the middle in the arrangement direction Z. First, the first sealing member 30A will be described with reference to FIGS. 3 to 5. In the following description, the side of the sealing members 30 and 31 on which the actuator main body 22 is located may be referred to as the inside in the axial direction X.

[0034] The first sealing member 30A has a semi-proximal end portion 40 and an insertion portion 50. The semi-proximal end portion 40 has an attachment portion 32, a locking portion 58, and a large diameter portion 54.

[0035] 3 and 4, the mounting portion 32, the locking portion 58, and the large diameter portion 54 each have a substantially semi-cylindrical shape. The centers of the arcs of the mounting portion 32, the locking portion 58, and the large diameter portion 54 (the centers of the entire circle when the arc extends around the entire circumference) are aligned along the axial direction X and coincide with the central axis S of the fluid pressure actuator 20 in an assembled state, as described below. In the following description, the chord side of the semicircle of the mounting portion 32, the locking portion 58, and the large diameter portion 54 (the negative arrow Z side) may be referred to as the "back side," and the opposite side (the positive arrow Z side) may be referred to as the "front side." In the following description, when the diameters of the mounting portion 32, the locking portion 58, and the large diameter portion 54 are mentioned, they will refer to the diameter of the semicircle (twice the radius of the semicircle).

[0036] 6, the dividing surface 33, which is the back surface of the semi-proximal end portion 40, is a flat surface that passes through the midpoint of the sealing member 30 in the arrangement direction Z and extends along the axial direction X. That is, as shown in FIG. 6, which will be described later, the dividing surface 33 overlaps with a surface that divides the sealing member 30 into a first sealing member 30A and a second sealing member 30B in the arrangement direction Z.

[0037] The mounting portion 32 has a diameter larger than the outer diameter of the tube 24, and an insertion portion 50 extends from one end of the mounting portion 32 in the axial direction X. The mounting portion 32 also has a flow path R that communicates with a connection hole H on the front side, passing through a radial center of the insertion portion 50, and the other end in the axial direction X (the side indicated by the arrow X+) (see also FIG. 6 ). An air supply hose (not shown) is connected to the connection hole H, and compressed air is supplied to the flow path R. The through hole 32T is a hole that penetrates from the surface of the mounting portion 32 to the dividing surface 33, located outside the connection hole H of the mounting portion 32 in the axial direction X (toward the far right in FIGS. 3 and 4 ). The mounting hole 32I is a hole that penetrates from the outer surface of the mounting portion 32 in the axial direction X (the surface on the front left in FIG. 2 ) to the through hole 32T. The mounting hole 32I is, as an example, a female thread into which a male thread member (not shown) is inserted, and the male thread member presses against a shaft member (not shown) that is passed through the through hole 32T, thereby fixing the fluid pressure actuator 20 to the shaft member (not shown).

[0038] The locking portion 58 is a portion that extends from the inner surface of the mounting portion 32 in the axial direction X toward the other side in the axial direction X, and has a smaller diameter than the mounting portion 32, as shown in Figures 3 and 4. The length of the locking portion 58 in the axial direction X is set appropriately in accordance with the shape of the locking ring 34 described above.

[0039] The large diameter portion 54 is a portion that extends from the surface on the other end side of the locking portion 58 toward the other side in the axial direction X, and has a larger diameter than the locking portion 58, as shown in Figures 3 and 4. The length of the large diameter portion 54 in the axial direction X is set appropriately in accordance with the shape of the above-mentioned crimping member 36.

[0040] A groove-shaped insertion groove 42 is formed in the dividing surface 33. As shown in FIG. 4 , the insertion groove 42 is formed on the back side of the half base end portion 40 from the surface on the other end side of the large diameter portion 54 toward the other end side in the axial direction X, and is a groove-shaped portion that is open on the large diameter portion 54 side in the axial direction X. The shape of the insertion groove 42 is appropriately set to match the shape of the restraining member 28. More specifically, the length W of the insertion groove 42 in the width direction Y, which is the distance between the side wall surfaces 42S, is slightly larger than the size of the restraining member 28 in the width direction Y. Furthermore, the size T of the insertion groove 42 in the depth direction, which is the length from the dividing surface 33 to the flat surface 42F, is slightly larger than half the thickness of the restraining member 28. Furthermore, the length D of the insertion groove 42 in the axial direction X, which is the length from the insertion portion 50 side to the bottom surface 42B, is set to a degree that, in the assembled fluid pressure actuator 20, the restraining member 28 is not compressed in the axial direction X and the restraining member 28 is sandwiched to a degree that prevents one end of the restraining member 28 from slipping out of the insertion groove 42. The insertion groove 42 of the first sealing member 30A and the insertion groove 42 of the second sealing member 30B, which will be described later, form an insertion portion 42H into which an end of the restraining member 28 can be inserted.

[0041] As shown in Fig. 4, the boss 44 is a portion that protrudes from the dividing surface 33 of the mounting portion 32, and is, for example, substantially cylindrical in shape. Also, as shown in Fig. 4, the recess 46 is a circular hole recessed in a position on the dividing surface 33 of the mounting portion 32 that is line-symmetrical to the boss 44 with respect to the central axis S of the fluid pressure actuator 20. The diameter of the recess 46 is slightly larger than the diameter of the boss 44, and the depth of the recess 46 is larger than the height of the boss 44.

[0042] 3 to 6 , the insertion portion 50 has a plurality of tapered portions that are connected in the axial direction X and that taper inward in the axial direction X. The tapered portions of the insertion portion 50 have an elliptical shape that is long in the width direction Y when viewed from the axial direction X. The insertion portion 50 is inserted into one end of the tube 24.

[0043] The area of ​​the insertion portion 50 as viewed from the axial direction X is slightly larger than the cross-sectional area of ​​the flow path R of the tube 24. More specifically, when the insertion portion 50 is inserted into one end side of the tube 24, the large-diameter portion of the tapered portion of the tube 24 is shaped to bite into the inner surface of the tube 24 even when the tube 24 is deformed along the ellipse.

[0044] The first sealing member 30A is preferably made of a metal such as stainless steel, but is not limited to such a metal and may be made of a hard plastic material or the like.

[0045] As shown in FIG. 2, the second sealing member 30B has the same shape as the first sealing member 30A across the dividing surface 33. As shown in FIG. 6, the first sealing member 30A and the second sealing member 30B can be overlapped with each other at their dividing surfaces 33. More specifically, in FIG. 6, the boss 44 of the first sealing member 30A fits into the recess 46 of the second sealing member 30B, and the boss 44 of the second sealing member 30B fits into the recess 46 of the first sealing member 30A, thereby overlapping the first sealing member 30A and the second sealing member 30B. In other words, the combination of the mating boss 44 and recess 46 is an example of a "fitting portion" in this embodiment, and in this embodiment, it can be said that the fluid pressure actuator 20 has a total of two fitting portions. Furthermore, as shown in FIG. 6, the first sealing member 30A and the second sealing member 30B are positioned by the fitting of the boss 44 and recess 46, respectively.

[0046] As shown in FIG. 6 , when the first sealing member 30A and the second sealing member 30B are overlapped with their dividing surfaces 33 facing each other, the combination of the paired insertion sections 50 is an example of an “insertion section pair” in this embodiment. When the first sealing member 30A and the second sealing member 30B are overlapped, the sealing member 30, which is the combination of the first sealing member 30A and the second sealing member 30B, is an example of a “sealing member pair” in this embodiment. Also, as shown in FIG. 2 , the pair of tubes 24 inserted into the pair of insertion sections 50 is an example of a “tube pair” in this embodiment. Also, as shown in FIG. 6 , the state in which the half proximal ends 40 are combined is an example of a “proximal end” in this embodiment. Also, as shown in FIG. 6 , the state in which the insertion grooves 42 face each other is an example of a “proximal end” in this embodiment.

[0047] The sealing member 31 provided at the other end side (the right side in FIG. 1 ) in the axial direction X of the fluid pressure actuator 20 has a lid portion 38 and a pair of insertion portions 50 .

[0048] The lid portion 38 of the sealing member 31 is similar to the mounting portion 32 in the sealing member 30, except that the connection hole H and the flow path R are not formed and the tip is rounded. The sealing member 31 is also similar to the sealing member 30, except that the pair of insertion portions 50 are integrated with the lid portion 38. In other words, the pair of insertion portions 50 in the sealing member 31 is another example of the "pair of insertion portions" in this embodiment.

[0049] Next, the assembly procedure for the fluid pressure actuator 20 in this embodiment will be described.

[0050] <Assembly of Fluid Pressure Actuator 20> As shown in FIGS. 2 to 7, at one end side of the fluid pressure actuator 20 in this embodiment, the sealing member 30 and the actuator main body 22 are assembled as follows.

[0051] First, the insertion portions 50 of the first sealing member 30A and the second sealing member 30B are inserted into the pair of tubes 24 until one end abuts against the large diameter portion 54.

[0052] The first sealing member 30A and the second sealing member 30B are overlapped, and one end of the restraining member 28 is inserted into the insertion portion 42H (the portion where the insertion grooves 42 face each other). As a result, the side wall surface 42S, flat surface 42F, and bottom surface 42B of the insertion portion 42H restrict movement of the restraining member 28 in one direction (toward the half base end portion 40) in the arrangement direction W, the width direction Y, and the axial direction X. In other words, the insertion portion 42H aligns the restraining member 28 in the axial direction X and positions the restraining member 28 so that it is sandwiched between the opposing portions of the pair of tubes 24.

[0053] Next, the sleeve 26 is hung up to the locking portion 58 of the tube 24 and the sealing member 30, covering the outer surface of the restraining member 28, and the locking ring 34 is attached from the radial outside of the sleeve 26 at the position of the locking portion 58, thereby locking the sleeve 26 to the locking portion 58.

[0054] Next, the sleeve 26 is folded back up to the insertion portion 50 of the sealing member 30 so that the locking ring 34 is on the inside, and the crimping member 36 is placed from the radial outside of the sleeve 26 to span the insertion portion 50 and the locking portion 58, and is then crimped using a crimping machine (not shown). As a result, the tube 24, the restraining member 28, and the sleeve 26 are fixed to the sealing member 30 at one end of the actuator body 22 in the axial direction X.

[0055] Next, on the other side of the tube 24 , sleeve 26 , and restraint member 28 in the axial direction X, the restraint member 28 is inserted into the insertion portion 42H of the sealing member 31 .

[0056] Next, while being careful not to remove the restraint member 28 from the insertion portion 42H of the sealing member 31, the pair of insertion portions 50 of the sealing member 31 are inserted into the other of the pair of tubes 24 in the axial direction X.

[0057] Next, the sleeve 26 is hung up to the locking portion 58 of the tube 24 and the sealing member 31 to cover the outer surface of the restraining member 28, and the locking ring 34 is attached from the radial outside of the sleeve 26 at the position of the locking portion 58, thereby locking the sleeve 26 to the locking portion 58.

[0058] Next, the sleeve 26 is folded back up to the insertion portion 50 of the sealing member 31 so that the locking ring 34 is on the inside, and the crimping member 36 is arranged from the radial outside of the sleeve 26 to span the insertion portion 50 and the locking portion 58, and is then crimped using a crimping machine (not shown). As a result, the tube 24, the restraining member 28, and the sleeve 26 are fixed to the sealing member 31 at the other end of the actuator body 22 in the axial direction X.

[0059] By following the above procedure, one end and the other end of the tube 24 are sealed with the sealing member 30 and the sealing member 31, and the fluid pressure actuator 20 is assembled.

[0060] Next, the operation of the fluid pressure actuator 20 in the present disclosure will be described.

[0061] <Operation of fluid pressure actuator 20> As shown in Figure 8, the fluid pressure actuator 20 is used with the sealing member 30 on one end fixed to a robot hand (not shown) or the like, and the sealing member 31 on the other end being a free end.

[0062] First, with the second sealing member 30B airtight, compressed air is introduced through the connection hole H of the first sealing member 30A, increasing the pressure inside the tube 24 connected to the first sealing member 30A. The tube 24 connected to the first sealing member 30A elastically deforms and expands due to the increased internal pressure, causing the sleeve 26 to perform pantograph deformation so that the angle θ increases, and a force acts in a direction that shortens the length of the actuator main body 22. At this time, the shortening of the actuator main body 22 is restricted by the restraining member 28, which is disposed at the opposing portion where the pair of tubes 24 are aligned. As a result, the outer peripheral wall of the actuator main body 22 on the side where the first sealing member 30A is disposed shortens as viewed from the axial direction X. This causes the restraining member 28 to flex and deform, and the entire actuator main body 22 bends toward the left side of the drawing, as indicated by the two-dot chain line in FIG. 8 .

[0063] Similarly, when compressed air is introduced through the connection hole H of the second sealing member 30B with the first sealing member 30A released from its airtight seal, the outer peripheral wall of the actuator body 22 on the side where the second sealing member 30B is disposed shortens as viewed from the axial direction X. This causes the restraint member 28 to flex and deform, and the entire actuator body 22 bends toward the right side of the drawing, as shown by the two-dot chain line in FIG.

[0064] In the present disclosure, the restraint member 28 has a length in the width direction Y, and therefore is less likely to bend in any direction other than the thickness direction, i.e., the alignment direction Z that intersects with the axial direction X of the sealing members 30 and 31.

[0065] In this way, in the fluid pressure actuator 20 of this embodiment, by supplying compressed air to the tube 24 of the first sealing member 30A or the second sealing member 30B, the fluid pressure actuator 20 can be bent toward the sealing member 30 to which the compressed air is supplied. In other words, by supplying compressed air to either sealing member 30, the fluid pressure actuator 20 of this embodiment can be bent toward both sides in the arrangement direction Z.

[0066] Next, the actions and effects of the fluid pressure actuator 20 according to the present disclosure will be described.

[0067] <Actions and Effects> Furthermore, in the fluid pressure actuator 20 according to this embodiment, the length of the insertion section 50 in the width direction Y is longer than the length in the alignment direction Z. This allows the cross-sectional area of ​​the tube 24 inserted into the insertion section 50 to be larger than when the length of the insertion section 50 in the alignment direction Z is equal to the length in the width direction Y. In other words, by increasing the cross-sectional area of ​​the tube 24, the strength of the force that bends the fluid pressure actuator 20 in the alignment direction Z can be increased compared to when the length of the insertion section 50 in the alignment direction Z is equal to the length in the width direction Y.

[0068] Furthermore, in the fluid pressure actuator 20 according to this embodiment, the shape of the insertion portion 50 is an ellipse that is long in the width direction Y. As a result, with the fluid pressure actuator 20 according to this embodiment, the manufacturing cost of the sealing member 30 can be reduced compared to when the shape of the insertion portion 50 is not an ellipse that is long in the width direction Y.

[0069] Furthermore, in the fluid pressure actuator 20 according to this embodiment, the end of the restraint member 28 is inserted into the insertion portion 42H outside the insertion portion 50 in the axial direction X, and therefore the restraint member 28 is less likely to shift after the fluid pressure actuator 20 is assembled.

[0070] Furthermore, in the fluid pressure actuator 20 according to this embodiment, the first sealing member 30A and the second sealing member 30B each have an insertion portion 50 formed therein, and the sealing portion is formed by overlapping the first sealing member 30A and the second sealing member 30B. As a result, according to the fluid pressure actuator 20 according to this embodiment, the manufacturing cost of the sealing member 30 can be reduced compared to when the sealing member 30 is formed as a single member.

[0071] Furthermore, in the fluid pressure actuator 20 according to this embodiment, the first sealing member 30A and the second sealing member 30B have the same shape on either side of the dividing surface 33, which reduces the number of different parts of the fluid pressure actuator 20. As a result, according to the fluid pressure actuator 20 according to this embodiment, the manufacturing cost of the sealing member 30 can be reduced compared to when the first sealing member 30A and the second sealing member 30B have different shapes.

[0072] Furthermore, in the fluid pressure actuator 20 according to this embodiment, when the first sealing member 30A and the second sealing member 30B are stacked together, a total of two fitting portions are formed on the dividing surface 33. The fitting portions position the first sealing member 30A and the second sealing member 30B by fitting the boss 44 into the recess 46. This allows the fluid pressure actuator 20 according to this embodiment to stack the first sealing member 30A and the second sealing member 30B with high precision. Furthermore, since the fluid pressure actuator 20 according to this embodiment has a total of two fitting portions, it is possible to reduce the risk of assembling the first sealing member 30A and the second sealing member 30B in the wrong orientation when stacking them together. Furthermore, since the fluid pressure actuator 20 according to this embodiment has a total of two fitting portions, it is possible to prevent the stacked first sealing member 30A and the second sealing member 30B from rotating relative to the dividing surface 33.

[0073] [Modification] In the above description, the shape of the insertion section 50 is an oval shape that is long in the width direction Y, but the technology of the present disclosure is not limited to this. The insertion section 50 may be long in the width direction Y, and may have, for example, an arc-shaped outer side in the arrangement direction Z (the side opposite to the opposing section).

[0074] Furthermore, in the above description, the end of the sealing member 30 in the axial direction X is sandwiched between the semi-proximal end portions 40, but the technology of the present disclosure is not limited to this. The restraint member 28 only needs to be provided across from one end side to the other end side of the pair of tubes 24 in the axial direction X, so for example, the insertion portion 42H does not need to be formed on the sealing member 30. In this case, both ends in the axial direction X may be configured to resist expansion and contraction of the tubes 24 by abutting against the large diameter portions 54 of the sealing member 30.

[0075] In the above description, the sealing member 30 is a pair of sealing members in which a first sealing member 30A on which one of the pair of insertion portions 50 is formed and a second sealing member 30B on which the other of the pair of insertion portions 50 is formed are overlapped in the arrangement direction Z. However, the technology according to the present disclosure is not limited to this. For example, as long as the pair of insertion portions 50 are formed side by side in the arrangement direction Z, the sealing member 30 may be formed integrally.

[0076] In the above description, the first sealing member 30A and the second sealing member 30B have the same shape across the dividing surface 33, but the technology according to the present disclosure is not limited to this. Since it is sufficient for the sealing member 30 to have a desired shape when the first sealing member 30A and the second sealing member 30B are overlapped, the first sealing member 30A and the second sealing member 30B may have different shapes.

[0077] In the above description, the first sealing member 30A and the second sealing member 30B each have a boss 44 and a recess 46, thereby forming a total of two mating portions, but the technology according to the present disclosure is not limited to this. For example, one of the first sealing member 30A and the second sealing member 30B may be formed with only a boss 44, and the other may be formed with only a recess 46. In addition, the total number of mating portions is not limited to two, and may be three or more, as long as there is more than one.

[0078] In these modified examples, if they have the same configuration as this embodiment, the same functions and effects as this embodiment can be obtained.

[0079] The above describes an embodiment of the present disclosure with reference to the accompanying drawings. However, it is clear that a person with ordinary knowledge in the field of technology to which the present disclosure pertains can conceive of various modifications or applications within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0080] The disclosure of Japanese Patent Application No. 2023-204237, filed on December 1, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A fluid pressure actuator comprising: a tube pair having a pair of tubes arranged in parallel and which expand and contract due to fluid pressure; a sleeve covering the outer peripheral surfaces of the pair of tubes and expanding the tubes radially while restricting axial extension as the tubes expand; an insertion portion pair having a pair of insertion portions into which axial ends of the tubes of the pair of tubes are respectively inserted, a sealing member for sealing the ends of each of the tubes; and a restraint member provided from one axial end side to the other axial end side of the pair of tubes and sandwiched between opposing portions where the tubes face each other, wherein each of the insertion portions has a length in a width direction perpendicular to the arrangement direction in which the insertion portions are arranged when viewed from the axial direction, which is longer than its length in the arrangement direction.

2. The fluid pressure actuator according to claim 1, wherein the insertion portion is elliptical in shape.

3. A fluid pressure actuator as described in claim 1, wherein the sealing member has a base end portion on the outside in the axial direction that is larger in diameter than the pair of insertion portions, and the restraint member has an end portion in the axial direction that is inserted into an insertion portion formed in the base end portion.

4. A fluid pressure actuator as described in any one of claims 1 to 3, wherein the sealing member is divided into a first sealing member in which one of the insertion portions is formed and a second sealing member in which the other of the insertion portions is formed, and the first sealing member and the second sealing member are formed by overlapping each other in the arrangement direction.

5. The fluid pressure actuator according to claim 4, wherein the first sealing member and the second sealing member have the same shape on either side of the dividing surface.

6. A fluid pressure actuator as described in claim 4, wherein a plurality of fitting portions are formed on the dividing surfaces, which position the first sealing member and the second sealing member by fitting boss portions into recesses when the first sealing member and the second sealing member are overlapped in the arrangement direction.

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