Fluid pressure actuator

Abstract

To provide a fluid pressure actuator which achieves reduction of positional deviation of a restraining member caused by force acting thereon.SOLUTION: A fluid pressure actuator 20 includes: a cylindrical tube 24; a sleeve 26 which covers the outer peripheral surface of the tube 24 and expands the tube in a radial direction by expansion of the tube while limiting extension of the tube in an axial direction; a pair of sealing members 32 each of which is provided with an insertion part 32B, having a taper part 49 in which a diameter is reduced toward the depth side of insertion, and seals a tube end; a restraining member 28 which is provided ranging from one side of the pair of the sealing members 32 to the other, includes restraining ends 29 which are disposed inclining along the taper parts 49, and may deform in an intersection direction intersecting the axial direction against compression along the axial direction; and a fixing member 36 which fixes the sleeve 26 and the restraining member 28 to the insertion parts 32B from the outer side of the sleeve 26 at positions corresponding to the restraining ends 29 of the restraining member 28.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention 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. The fluid pressure actuator includes a restraint member provided from one end side to the other end side in the axial direction inside the sleeve. 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 a force is applied to the tip of the fluid pressure actuator, particularly when the direction of the force received from the object intersects the axial direction (for example, when lifting an object with the axial direction of the fluid pressure actuator being horizontal), there is a concern that the position of the restraint member is likely to shift.

[0005] An object of the present invention is to provide a fluid pressure actuator that reduces the positional shift of the restraint member due to the application of a force.

Means for Solving the Problems

[0006] The fluid pressure actuator of the first aspect includes 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 the tube in the radial direction while restricting the axial elongation of the tube due to the expansion of the tube, an insertion portion formed by inserting tube end portions on one side and the other side in the axial direction of the tube from the tip side, respectively, and having a tapered portion that becomes smaller in diameter toward the inner side of the insertion, a pair of sealing members that seal the tube end portions, a restraining member provided on the inner side in the radial direction of the sleeve, extending from one side to the other side of the pair of sealing members, having a restraining end portion inclined so as to follow the tapered portion, resisting compression along the axial direction, and deformable in a crossing direction crossing the axial direction, and a fixing member that fixes the sleeve and the restraining member to the insertion portion from the outside of the sleeve at a position corresponding to the restraining end portion of the restraining member.

[0007] In the fluid pressure actuator of the first aspect, a tapered portion that becomes smaller in diameter toward the inner side of the insertion is formed in the insertion portion of the sealing member that seals the tube end portion. The restraining end portion of the restraining member is inclined so as to follow the tapered portion and is fixed to the insertion portion by the fixing member from the outside. In this way, by fixing the restraining end portion of the restraining member to the insertion portion using a portion having a smaller diameter than the expanding and contracting portion of the fluid pressure actuator, the force acting in the circumferential direction on the restraining end portion can be reduced.

[0008] In the fluid pressure actuator of the second aspect, the sealing member has a base end portion having a larger diameter than the insertion portion on the side opposite to the side where the tube of the insertion portion is inserted, and a small diameter portion that is continuous with the tapered portion and has a continuous same diameter in the axial direction is formed at the boundary portion between the insertion portion and the base end portion, and the restraining end portion is disposed to extend to the small diameter portion.

[0009] According to the fluid pressure actuator of the second aspect, a small diameter portion is formed between the base end portion of the sealing member and the insertion portion, and the restraining end portion is disposed to extend to the small diameter portion and can be stably fixed.

[0010] In the fluid pressure actuator according to the third aspect, in the fluid pressure actuator according to the second aspect, the restraint end portion is disposed so as to abut against the step between the small diameter portion and the base end portion.

[0011] According to the fluid pressure actuator of the third aspect, axial displacement of the restraint end portion can be prevented.

[0012] The fluid pressure actuator according to the fourth aspect further includes a locking wire that fixes the restraint end portion to the small diameter portion via the sleeve in the fluid pressure actuator according to the second or third aspect.

[0013] According to the fluid pressure actuator of the fourth aspect, stronger fixation of the restraint end portion can be achieved with the locking wire.

[0014] In the fluid pressure actuator according to the fifth aspect, in the fluid pressure actuator according to the first to fourth aspects, the restraint end portion is disposed in contact with the insertion portion in the tapered portion.

[0015] According to the fluid pressure actuator of the fifth aspect, since the restraint end portion is in contact with the insertion portion without passing through the tube, stronger fixation can be achieved.

Advantages of the Invention

[0016] According to the present invention, displacement of the restraint member due to the action of force can be reduced.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments for realizing the technology of the present disclosure will be described in detail with reference to the drawings.

[0019] In addition, components and processes that perform the same functions may be given the same reference numerals throughout the drawings, and redundant explanations 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.

[0020] As shown in FIG. 1, a fluid pressure actuator 20 according to an embodiment of the present disclosure includes an actuator main body portion 22, a first sealing member 30A, and a second sealing member 30B.

[0021] As also shown in FIG. 2, the actuator main body portion 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 due to elastic deformation, and expands and contracts due to a change in the pressure of the fluid inside. The axial direction S of the tube 24 is referred to 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 driven by hydraulic pressure, it is preferably at least one selected from the group consisting of NBR (nitrile rubber) having high oil resistance, hydrogenated NBR, chloroprene rubber, and epichlorohydrin rubber.

[0022] 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 the axial direction S at a predetermined angle θ. By having such a shape, the sleeve 26 undergoes a pantograph deformation that changes the angle θ and follows the contraction and expansion of the tube 24 while restricting the contraction and expansion of the tube 24.

[0023] As the cords constituting the sleeve 26, it is preferable to use fiber cords 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.

[0024] 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 S 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.

[0025] The restraint member 28 includes a restraint main body portion 28A and restraint end portions 29. The restraint main body portion 28A is the portion arranged along the axial direction S of the tube 24. The restraint end portions 29 are formed at both ends of the restraint member 28. The restraint end portions 29 have a bent shape having an inclined portion 29A and a tip portion 29B. The inclined portion 29A is bent so as to incline radially inward from the restraint main body portion 28A toward the end. The tip portion 29B extends continuously from the inclined portion 29A and is parallel to the restraint main body portion 28A.

[0026] The restraint member 28 is formed of a material that does not expand or contract under pressure and is capable of flexing and deforming in a 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 gripping force, and the like. Also, the material of the leaf spring is not particularly limited, but typically, a material that is easily flexibly deformed and strong against compression, such as a metal such as stainless steel, may be used. Alternatively, it may be formed of a thin plate of carbon fiber reinforced plastic (CFRP) or the like.

[0027] The first sealing member 30A has a sealing member connector 32, a locking wire 34, and a fixing member 36.

[0028] As shown in FIGS. 3 and 4, the sealing member connector 32 has an integrally formed base end portion 32A and an insertion portion 32B. The base end portion 32A has a substantially rectangular parallelepiped shape with a diameter larger than the outer diameter of the tube 24, and the insertion portion 32B extends in the axial direction S from the center of one end side of the base end portion 32A. The insertion portion 32B has a small diameter portion 48, a tapered portion 49, a large diameter portion 50, and a bamboo shoot portion 52 in order from the base end portion 32A side.

[0029] The bamboo shoot portion 52 is formed to protrude on the tip side of the insertion portion 32B, and the tube 24 is inserted from the tip of the bamboo shoot portion 52. The bamboo shoot portion 52 is formed in three stages with a tapered shape in which the base end portion 32A side has a larger diameter. The large diameter portion 50 is continuously formed on the base end portion 32A side of the bamboo shoot portion 52 and has a disk shape with a diameter larger than that of the bamboo shoot portion 52. A step 42 is formed between the large diameter portion 50 and the bamboo shoot portion 52.

[0030] The tapered portion 49 is continuously formed from the large diameter portion 50 on the base end portion 32A side (the back side of the insertion portion 32B) of the large diameter portion 50 and has a tapered shape that becomes smaller in diameter toward the base end portion 32A side. The end portion of the tapered portion 49 on the base end portion 32A side has a smaller diameter than the tip of the bamboo shoot portion 52.

[0031] The small-diameter portion 48 is formed between the tapered portion 49 and the base-end portion 32A, and has the same diameter from the tapered portion 49 to the base-end portion 32A. The outer diameter of the small-diameter portion 48 is smaller than the tip of the bamboo shoot portion 52. A step 35 is formed between the small-diameter portion 48 and the base-end portion 32A.

[0032] As the sealing member connector 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.

[0033] As shown in FIG. 4, in the sealing member connector 32, as viewed from the axial direction S, a flow path R is formed which extends in the axial direction S at the center of the insertion portion 32B and communicates with the connection hole H on the side surface of the base-end portion 32A. (See also FIG. 7). An air supply hose (not shown) is connected to the connection hole H, and compressed air is supplied to the flow path R.

[0034] The restraining end portion 29 of the restraining member 28 is arranged at positions corresponding to the tapered portion 49 and the small-diameter portion 48 of the sealing member connector 32 in the axial direction S. The restraining end portion 29 is in direct contact with the insertion portion 32B without passing through the tube 24 (see FIG. 4). The inclined portion 29A of the restraining end portion 29 is arranged along the tapered portion 49 so that the end portion side inclines inward in the radial direction. The tip portion 29B of the restraining end portion 29 extends from the inclined portion 29A and is arranged along the small-diameter portion 48, and the end face abuts against the step 35 between the base-end portion 32A and the small-diameter portion 48.

[0035] The locking wire 34 is in a ring shape formed by winding the wire a plurality of times, and is wound around the outside of the sleeve 26 so as to sandwich the sleeve 26 between it and the small-diameter portion 48. Further, the sleeve 26 is folded back to the outer periphery via the locking wire 34. Thereby, the sleeve 26 is locked to the sealing member connector 32. As the locking wire 34, a wire made of metal can be used.

[0036] The fixing member 36 is arranged to cover the insertion portion 32B on the outer periphery of the actuator main body portion 22. As shown in FIG. 5, at the portion corresponding to the bamboo shoot portion 52 inside the fixing member 36, the bamboo shoot portion 52, the tube 24, the restraint main body portion 28A of the restraint member 28, the sleeve 26 (before folding), and the sleeve 26 (after folding) are arranged. As shown in FIG. 6, at the portion corresponding to the small-diameter portion 48 inside the fixing member 36, the small-diameter portion 48, the tip portion 29B of the restraint member 28, the sleeve 26 (before folding), the locking wire 34, and the sleeve 26 (after folding) are arranged.

[0037] By caulking the fixing member 36 radially inward, the tube 24, the restraint member 28, and the sleeve 26 can be fixed to the sealing member connector 32.

[0038] Subsequently, the assembly procedure of the fluid pressure actuator 20 in the present embodiment will be described.

[0039] <Assembly of the fluid pressure actuator 20>

[0040] As shown in FIGS. 2 and 5, at one end side of the fluid pressure actuator 20 in the present embodiment, the first sealing member 30A and the actuator main body portion 22 are assembled as follows.

[0041] First, insert the tube 24 into the insertion portion 32B of the sealing member connector 32 until one end of the tube 24 abuts against the step 42. Next, arrange the restraint member 28 such that the inclined portion 29A of the restraint end portion 29 is arranged along the tapered portion 49, the tip portion 29B of the restraint end portion 29 is arranged along the small-diameter portion 48, and the end face of the tip portion 29B abuts against the step 35.

[0042] Next, cover the outer peripheral surface of the restraint member 28 while hanging the sleeve 26 on the tube 24 and the base end portion 32A of the sealing member connector 32, and wind the locking wire 34 from the radially outer side of the sleeve 26 and attach it to the position of the small-diameter portion 48.

[0043] Next, fold the sleeve 26 back to the insertion portion 32B of the sealing member connector 32 so that the locking wire 34 is on the inside, and arrange the fixing member 36 from the radially outer side of the sleeve 26 so as to extend over the end portion of the small-diameter portion 48 of the insertion portion 32B, and caulking-fix it. Thereby, on one side in the axial direction S of the actuator main body portion 22, the tube 24, the restraining member 28, and the sleeve 26 are fixed to the sealing member connector 32.

[0044] Next, on the other side in the axial direction S, the second sealing member 30B and the actuator main body portion 22 are assembled in the same manner as the first sealing member 30A.

[0045] By the above procedure, 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.

[0046] Subsequently, the operation of the fluid pressure actuator 20 in the present disclosure will be described.

[0047] <Operation of the fluid pressure actuator 20>

[0048] As shown in FIG. 7, the fluid pressure actuator 20 is used such that 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.

[0049] When compressed air is introduced 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, the sleeve 26 undergoes a pantograph deformation so that the angle θ increases, and a force acts in the direction in which the length 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 outer peripheral wall of the actuator main body portion 22 on the side where the restraining member 28 is not arranged shortens as viewed from the axial direction S. As a result, the restraining member 28 is elastically deformed, and as shown by the two-dot chain line in FIG. 7, the entire actuator main body portion 22 is curved.

[0050] In the present disclosure, since the restraining member 28 has a length in the width direction, it is difficult to bend in a direction other than the plate thickness direction, that is, the direction (hereinafter referred to as "crossing direction X") crossing the axial direction S in the first sealing member 30A and the second sealing member 30B. In other words, as shown in FIG. 7, the restraining member 28 bends in the direction toward the axis of the tube 24.

[0051] If a plurality of such fluid pressure actuators 20 that bend in this way are prepared, the object can be held by the plurality of fluid pressure actuators 20.

[0052] Subsequently, the operation and effect of the fluid pressure actuator 20 according to the present disclosure will be described.

[0053] <Operation and effect>

[0054] In the fluid pressure actuator 20 in the present disclosure, the restraining end portion 29 of the restraining member 28 is fixed to the insertion portion 32B by also using a tapered portion 49 and a small diameter portion 48 having a smaller diameter than the actuator main body portion 22 which is the portion where the fluid pressure actuator 20 expands and contracts. Thereby, the force acting in the circumferential direction on the restraining end portion 29 can be reduced, and the displacement of the restraining member 28 due to the acting force can be reduced.

[0055] In the present embodiment, an example in which the restraining end portion 29 has a tip portion 29B disposed along the small diameter portion 48 has been described, but the tip portion 29B is not necessarily required. By providing the tip portion 29B and disposing it along the small diameter portion 48 as in the present embodiment, the restraining member 28 can be fixed more stably. Further, by abutting the tip portion 29B against the step 35, the axial displacement of the restraining member 28 can be prevented.

[0056] In the present embodiment, the restraining end portion 29 is in direct contact with the insertion portion 32B without passing through the tube 24. Therefore, the restraining member 28 can be fixed to the insertion portion 32B more firmly as compared with the case of passing through the tube 24.

[0057] The embodiments of the present disclosure have been described above 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

[0058] 20 Fluid pressure actuator 24 Tube 26 Sleeve 28 Restraining member 28A Restraining main body portion 29 Restraining end portion 29A Inclined portion 29B Tip portion 30A First sealing member 30B Second sealing member 32 Sealing member connector 32A Base end portion 32B Insertion portion 34 Locking wire 35 Step 36 Fixing member 48 Small diameter portion 49 Tapered portion

Claims

1. A cylindrical tube that expands and contracts according to the pressure of a fluid, A sleeve that covers the outer peripheral surface of the tube and expands the tube in the radial direction while restricting the axial elongation of the tube due to the expansion of the tube, A pair of sealing members formed with insertion portions having tapered portions that become smaller in diameter toward the inner side of the insertion, into which the tube end portions on one side and the other side in the axial direction of the tube are inserted from the tip side, respectively, for sealing the tube end portions, A restraining member provided across from one side to the other side of the pair of sealing members inside the sleeve in the radial direction, inclined so that the restraining end portion follows the tapered portion, resistant to compression along the axial direction, and deformable in an intersecting direction intersecting the axial direction, A fixing member that fixes the sleeve and the restraining member to the insertion portion from the outside of the sleeve at a position corresponding to the restraining end portion of the restraining member, A fluid pressure actuator comprising the above.

2. The sealing member has a base end portion having a larger diameter than the insertion portion on the side opposite to the side where the tube of the insertion portion is inserted, and a small diameter portion that is continuous from the tapered portion and has a continuous same diameter in the axial direction is formed at the boundary portion of the insertion portion with the base end portion, The restraining end portion is disposed to extend into the small diameter portion, The fluid pressure actuator according to Claim 1.

3. The restraining end portion is disposed to abut against the step between the small diameter portion and the base end portion, The fluid pressure actuator according to Claim 2.

4. The fluid pressure actuator according to Claim 2, further comprising a locking wire that fixes the restraining end portion to the small diameter portion via the sleeve.

5. The restraining end portion is disposed in contact with the insertion portion in the tapered portion, The fluid pressure actuator according to any one of Claims 1 to 4.

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