JP6585946B2 - Fluid pressure actuator - Google Patents

Description

  The present invention relates to a fluid pressure actuator that expands and contracts a tube using a gas or a liquid, and more specifically, to a so-called Macchiben type fluid pressure actuator.

  Conventionally, a fluid pressure actuator for expanding and contracting a tube as described above has a rubber tube (tubular body) that expands and contracts by air pressure, and a sleeve (network reinforcement structure) that covers the outer peripheral surface of the tube. Structures (so-called McKibben type) are widely used (for example, Patent Document 1).

  Both ends of the actuator main body constituted by the tube and the sleeve are caulked using a sealing member made of metal.

  The sleeve is a cylindrical structure in which high-strength fibers such as polyamide fibers or metal cords are knitted, and regulates the expansion motion of the tube within a predetermined range.

  Such a fluid pressure actuator is used in various fields, and is particularly preferably used as an artificial muscle of a care / welfare device.

JP-A-61-236905

  In the fluid pressure actuator as described above, higher contraction force is required. For example, in addition to artificial muscles of care / welfare equipment, a fluid pressure actuator used for a robot requires a higher contraction force.

  In order to realize such a high contraction force, it is conceivable to use a hydraulic drive using mineral oil or the like as a fluid. However, in the case of hydraulic drive, since a significantly high pressure is applied to the tube and the sleeve, high durability is required.

  When such a high pressure is applied to the inside of the fluid pressure actuator, the possibility that the actuator main body portion is damaged increases. In particular, there is a concern that the sleeve that regulates the expansion range of the tube may be damaged, or that the tube may be damaged due to stress concentration on a specific portion of the tube.

  Therefore, the present invention has been made in view of such a situation, and an object thereof is to provide a fluid pressure actuator having sufficient durability even when a high pressure is applied, such as a hydraulic drive.

  A fluid pressure actuator (fluid pressure actuator 10) according to one embodiment of the present invention is a braided cylindrical tube (tube 110) that expands and contracts by fluid pressure and a cord (cord 121) oriented in a predetermined direction. An actuator main body (actuator main body 100) that is a structure and is configured by a sleeve (sleeve 120) that covers the outer peripheral surface of the tube. The cord is made of an organic fiber. The fluid pressure actuator has a covering layer (covering layer 122) covering the surface of the cord. The coating layer is formed of a mixture of a thermosetting resin and latex.

  In one embodiment of the present invention, the coating layer may be formed using a mixed aqueous solution in which the solid content ratio (wt%) of the thermosetting resin and the latex is 15% or more and 50% or less.

  In one embodiment of the present invention, the thermosetting resin may be a blend of any one or more of a phenol resin, a resorcin resin, and a urethane resin.

  In one embodiment of the present invention, the latex may be a blend of one or more of VP latex, SBR latex, and NBR latex.

  In one aspect of the present invention, the fluid pressure actuator includes a sealing member (for example, a sealing member 210) that seals an end of the actuator main body in the axial direction, and the sealing member includes the sleeve. A rubber sheet (for example, rubber sheet 250) that comes into contact with may be included.

  The fluid pressure actuator according to one aspect of the present invention has sufficient durability even when a high pressure is applied, such as a hydraulic drive.

FIG. 1 is a side view of the fluid pressure actuator 10. FIG. 2 is a partially exploded perspective view of the fluid pressure actuator 10. FIG. 3 is a partial cross-sectional view along the axial direction D _AX of the fluid pressure actuator 10 including the sealing mechanism 200. FIG. 4 is a partially developed perspective view of the actuator body 100. FIG. 5 is a cross-sectional view of the cord 121 along the radial direction. FIG. 6 is a partial cross-sectional view along the axial direction D _AX of the fluid pressure actuator 10 including the sealing mechanism 200 according to the first modification. Figure 7 is a partial cross-sectional view taken along the axial direction D _AX of the fluid pressure actuator 10 which includes a sealing mechanism 200A according to Modification 2.

  Hereinafter, embodiments will be described with reference to the drawings. The same functions and configurations are denoted by the same or similar reference numerals, and description thereof is omitted as appropriate.

(1) Overall Schematic Configuration of Fluid Pressure Actuator FIG. 1 is a side view of a fluid pressure actuator 10 according to the present embodiment. As shown in FIG. 1, the fluid pressure actuator 10 includes an actuator main body 100, a sealing mechanism 200, and a sealing mechanism 300. In addition, connecting portions 20 are provided at both ends of the fluid pressure actuator 10, respectively.

  The actuator main body 100 is composed of a tube 110 and a sleeve 120. A fluid flows into the actuator main body 100 through the fitting 400 and the passage hole 410.

Actuator body portion 100, the inflow of fluid into the tube 110, contracts in the axial direction D _AX of the actuator body portion 100 expands in the radial direction D _R. Further, the actuator body portion 100, the outflow of the fluid from the tube 110, expanded in the axial direction D _AX of the actuator body portion 100, to shrink in the radial direction D _R. Due to such a shape change of the actuator main body 100, the fluid pressure actuator 10 exhibits a function as an actuator.

  The fluid used to drive the fluid pressure actuator 10 may be either a gas such as air or a liquid such as water or mineral oil. In particular, the fluid pressure actuator 10 is a hydraulic drive that applies high pressure to the actuator body 100. High durability that can withstand

  Further, such a fluid pressure actuator 10 is a so-called McKibben type, and can be applied to artificial muscles as well as robot limbs (upper limbs, lower limbs, etc.) that require higher ability (contraction force). Can also be suitably used. The connecting part 20 is connected to members constituting the limb.

Sealing mechanism 200 and the sealing mechanism 300 seals both end portions of the actuator body portion 100 in the axial direction D _AX. Specifically, the sealing mechanism 200 includes a sealing member 210 and a caulking member 230. The sealing member 210 seals the end portion in the axial direction D _AX of the actuator body portion 100. The caulking member 230 caulks the actuator main body 100 together with the sealing member 210. On the outer peripheral surface of the caulking member 230, an indentation 231 is formed, which is a mark in which the caulking member 230 is caulked by a jig.

  The difference between the sealing mechanism 200 and the sealing mechanism 300 is whether or not the fitting 400 (and the passage hole 410) is provided.

  The fitting 400 protrudes so that a drive pressure source of the fluid pressure actuator 10, specifically, a hose (pipe) connected to a gas or liquid compressor can be attached. The fluid that flows in through the fitting 400 passes through the passage hole 410 and flows into the actuator main body 100, specifically, the tube 110.

  FIG. 2 is a partially exploded perspective view of the fluid pressure actuator 10. As shown in FIG. 2, the fluid pressure actuator 10 includes an actuator main body 100 and a sealing mechanism 200.

  The actuator body 100 is constituted by the tube 110 and the sleeve 120 as described above.

  The tube 110 is a cylindrical tubular body that expands and contracts by the pressure of a fluid. The tube 110 is repeatedly contracted and expanded by the fluid.

  The sleeve 120 has a cylindrical shape and covers the outer peripheral surface of the tube 110. The sleeve 120 is a structure in which cords oriented in a predetermined direction are knitted, and the rhombus shape is repeated when the oriented cords intersect. Since the sleeve 120 has such a shape, the sleeve 120 is deformed into a pantograph and follows while restricting contraction and expansion of the tube 110.

  The material of the cord constituting the sleeve 120 will be described later.

Sealing mechanism 200 seals the end portion in the axial direction D _AX of the actuator body portion 100. The sealing mechanism 200 includes a sealing member 210, a locking ring 220, and a caulking member 230.

  The sealing member 210 has a body part 211 and a flange part 212. As the sealing member 210, a metal such as stainless steel can be suitably used, but is not limited to such a metal, and a hard plastic material or the like may be used.

  The body part 211 has a circular tube shape, and a passage hole 215 through which a fluid passes is formed in the body part 211. The passage hole 215 communicates with the passage hole 410 (see FIG. 1). The tube 110 is inserted through the body portion 211.

The flange portion 212 is connected to the body portion 211, and is located closer to the end portion in the axial direction _DAX of the fluid pressure actuator 10 than the body portion 211. The collar portion 212 has an outer diameter larger than that of the body portion 211. The flange portion 212 locks the tube 110 and the locking ring 220 inserted through the body portion 211.

  An uneven portion 213 is formed on the outer peripheral surface of the body portion 211. The uneven portion 213 contributes to suppression of slippage of the tube 110 inserted through the body portion 211. Further, a small-diameter portion 214 having a smaller outer diameter than the body portion 211 is formed at a position near the flange portion 212 of the body portion 211. The shape of the small diameter portion 214 will be further described in FIG.

The locking ring 220 locks the sleeve 120. Specifically, the sleeve 120 is folded radially D _R outward through the locking ring 220 (not shown in FIG. 2, see FIG. 3).

The outer diameter of the locking ring 220 is larger than the outer diameter of the body portion 211. The locking ring 220 locks the sleeve 120 at the position of the small diameter portion 214 of the body portion 211. That is, the locking ring 220, a radial direction D _R outside of the body 211, in a position adjacent to the flange portion 212, locking the sleeve 120.

  Since the locking ring 220 is locked to the small-diameter portion 214 smaller than the body portion 211, in this embodiment, the locking ring 220 has a two-divided shape. The locking ring 220 is not limited to being divided into two parts, and may be divided into more parts, or some of the divided parts may be rotatably connected.

  As the locking ring 220, the same metal as the sealing member 210, a hard plastic material, or the like can be used.

  The caulking member 230 caulks the actuator main body 100 together with the sealing member 210. As the caulking member 230, a metal such as an aluminum alloy, brass, or iron can be used. When the caulking member 230 is caulked by a caulking jig, an indentation 231 as shown in FIG. 1 is formed on the caulking member 230.

(2) Configuration of Sealing Mechanism FIG. 3 is a partial cross-sectional view of the fluid pressure actuator 10 including the sealing mechanism 200 along the axial direction _DAX .

  As described above, the sealing member 210 has the small diameter portion 214 having an outer diameter smaller than the outer diameter of the body portion 211.

Locking ring 220 is positioned radially D _R outside of the small-diameter portion 214. The inner diameter R1 of the locking ring 220 is smaller than the outer diameter R3 of the body portion 211. The outer diameter R2 of the locking ring 220 may also be smaller than the outer diameter R3 of the body portion 211.

The tube 110 is inserted through the body portion 211 until it comes into contact with the flange portion 212. On the other hand, the sleeve 120 is folded back radially D _R outward through the locking ring 220. As a result, the sleeve 120 has a folded portion 120 a that is folded back via the locking ring 220.

Folded portion 120a, the sleeve 120 located radially D _R outside of the tube 110, i.e., is bonded to the sleeve 120 before being folded at the locking ring 220.

  Specifically, an adhesive layer 240 is formed between the sleeve 120 and the folded portion 120a. For the adhesive layer 240, an appropriate adhesive may be used depending on the type of cord constituting the sleeve 120.

  The caulking member 230 is larger than the outer diameter of the body portion 211 of the sealing member 210, and is caulked by a jig after being inserted into the body portion 211. The caulking member 230 caulks the actuator main body 100 together with the sealing member 210.

Specifically, the caulking member 230, the tube 110 is inserted into body portion 211, radially D _R sleeve 120 located outside the tube 110, and the folded portion 120a is caulked. That is, the caulking member 230 caulks the tube 110, the sleeve 120, and the folded portion 120a together with the sealing member 210.

(3) Configuration of Actuator Body 100 FIG. 4 is a partially developed perspective view of the actuator body 100. As shown in FIG. 4, the actuator main body 100 includes a tube 110 and a sleeve 120.

  The tube 110 is a cylindrical body (tubular body) made of an elastic material such as butyl rubber. Further, when the fluid pressure actuator 10 is hydraulically driven, NBR (nitrile rubber) having high oil resistance may be used.

  The sleeve 120 is provided so as to cover the outer peripheral surface of the tube 110. The sleeve 120 is formed by weaving a plurality of cords 121 oriented so as to cross each other.

  FIG. 5 is a cross-sectional view of the cord 121 along the radial direction. As shown in FIG. 5, the sleeve 120 has a covering layer 122 that covers the surface of the cord 121.

  4 and 5, the two cords 121 are paired and the cords 121 are oriented so as to cross each other. However, the number of cords 121 to be paired is other than two (monofilament or multifilament). Filament). In the case of two or more wires, the cords 121 may be twisted.

  The cord 121 is formed of an organic fiber cord. Specifically, the cord 121 is preferably an aromatic polyamide (aramid fiber) or polyethylene terephthalate (PET) fiber cord. However, cords of organic fibers other than such fiber cords may be used. The diameter of the fiber cord is not particularly limited as long as it does not hinder the operation of the actuator body 100.

  Note that the cord 121 may be pretreated with a reactive agent such as an epoxy resin in order to enhance the adhesiveness with the aqueous mixture that forms the coating layer 122.

  The coating layer 122 is formed of a mixture of a thermosetting resin and latex. Specifically, the coating layer 122 is formed by applying a mixture aqueous solution of a thermosetting resin and latex to the cord 121, and then drying and thermosetting.

  The coating layer 122 is preferably formed using a mixed aqueous solution in which the solid content (wt%) of the thermosetting resin and latex is 15% or more and 50% or less. The solid content is more preferably 20% or more and 40% or less.

  As the thermosetting resin, it is preferable to use any one of a phenol resin, a resorcin resin, and a urethane resin. Alternatively, a mixture of a plurality of these resins may be used.

  As latex, either VP (styrene / butadiene / vinyl pyridine copolymer) latex, SBR (low styrene / butadiene copolymer) latex, or NBR (butadiene / acrylonitrile copolymer) latex, or a plurality thereof was blended. It is preferable to use one.

(4) Modified Example Next, a modified example of the fluid pressure actuator 10 described above will be described. Specifically, a modified example of the sealing mechanism 200 will be described. In the following, the parts different from the fluid pressure actuator 10 described above will be mainly described.

(4.1) Modification 1
FIG. 6 is a partial cross-sectional view along the axial direction D _AX of the fluid pressure actuator 10 including the sealing mechanism 200 according to the first modification.

  In the present modification, the sealing member 210 includes a rubber sheet 250 and a rubber sheet 260. Specifically, a rubber sheet 260 is used instead of the adhesive layer 240 shown in FIG.

  The rubber sheet 250 and the rubber sheet 260 are sheet-like elastic members and come into contact with the sleeve 120.

  Specifically, the rubber sheet 250 is provided so as to cover the outer peripheral surface of the cylindrical folded portion 120a. The rubber sheet 260 is provided between the sleeve 120 and the folded portion 120a.

  The rubber types of the rubber sheet 250 and the rubber sheet 260 are not particularly limited, but it is preferable to use a synthetic rubber having the same composition as the latex used for forming the coating layer 122.

(4.2) Modification 2
Figure 7 is a partial cross-sectional view taken along the axial direction D _AX of the fluid pressure actuator 10 which includes a sealing mechanism 200A according to Modification 2. As shown in FIG. 7, a sealing mechanism 200A is used instead of the sealing mechanism 200 shown in FIGS. The difference between the sealing mechanism 200 and the sealing mechanism 200A is that the small-diameter portion 214 like the sealing member 210 is not formed. Further, the locking ring 220 is not used in the sealing mechanism 200A.

  The tube 110 is inserted through the body portion 211A of the sealing member 210A. In the sealing mechanism 200A, since the locking ring 220 is not used, the sleeve 120 is not folded back.

  The caulking member 230A caulks the tube 110 and the sleeve 120 together with the sealing member 210A.

  In this modified example, the adhesive layer 240 is formed similarly to the sealing mechanism 200 shown in FIG. 3, but a rubber sheet similar to the rubber sheet 250 may be provided instead of the adhesive layer 240. .

(5) Actions and Effects Hereinafter, actions and effects of the fluid pressure actuator 10 according to the present embodiment described above will be described.

  Table 1 shows the configurations and evaluation test results of the fluid pressure actuators according to the comparative example and the example.

表１に示すように、被覆層の構成が異なる比較例１〜３及び実施例１〜３に係る流体圧アクチュエータを作成し、流体圧アクチュエータの耐久性について評価試験を実施した。

As shown in Table 1, fluid pressure actuators according to Comparative Examples 1 to 3 and Examples 1 to 3 having different coating layer configurations were prepared, and an evaluation test was performed on the durability of the fluid pressure actuator.

  In Comparative Examples 1 and 3, the solid content ratio (wt%) of the mixed aqueous solution of the thermosetting resin and latex used for forming the coating layer is 15% or more and 50% or less (preferably, 20% or more, 40% % Or less). In Comparative Example 2, latex is not used for the coating layer. On the other hand, in Examples 1 to 3, the solid content ratio (wt%) of the mixed aqueous solution is in the range of 20% to 40%.

  In the durability evaluation test, each fluid pressure actuator was driven with hydraulic pressure, and the number of operations (time) until some damage occurred in the actuator body was measured. The numerical value in the column of “Durability” indicates an index when the measurement result of Comparative Example 1 is 100.

  In Examples 1 to 3, since a mixture of a thermosetting resin and a latex is used for the coating layer and the solid content is 20% or more and 40% or less, it is understood that the durability is greatly improved.

  As described above, according to the fluid pressure actuator 10, the cord 121 is made of an organic fiber, and the coating layer 122 that covers the surface of the cord 121 is formed of a mixture of a thermosetting resin and latex.

  In a McKibben type fluid pressure actuator such as the fluid pressure actuator 10, when the actuator main body 100 repeatedly contracts and expands due to friction between the cord 121 of the organic fiber and the tube 110, or damage due to friction of the cord 121 itself. Durability can be a problem.

  According to the fluid pressure actuator 10, since the coating layer 122 formed of a mixture of a thermosetting resin and latex covers the surface of the cord 121, the friction coefficient of the surface of the cord 121 is reduced while preventing the cord 121 from being damaged. It can be reduced moderately.

  That is, the fluid pressure actuator 10 has sufficient durability even when a high pressure is applied, such as when hydraulically driven.

  In the present embodiment, the coating layer 122 is a mixture aqueous solution in which the solid content ratio (wt%) between the thermosetting resin and the latex is 15% or more and 50% or less (preferably 20% or more and 40% or less). Can be formed. Further, the thermosetting resin is one in which any one or a plurality of phenol resins, resorcin resins, and urethane resins are blended. Furthermore, the latex is a blend of one or more of VP latex, SBR latex, and NBR latex.

  As a result, the coefficient of friction of the surface of the cord 121 can be appropriately reduced while covering the surface of the cord 121 made of organic fiber easily and reliably.

  In the present embodiment, the sealing member 210 includes a rubber sheet 250 and a rubber sheet 260 that come into contact with the sleeve 120. Sealing the sleeve 120 (cord 121) having a reduced coefficient of friction by caulking the sleeve 120 constituted by the cord 121 covered with the covering layer 122 in contact with the rubber sheet 250 and the rubber sheet 260 in this manner. This is effective for preventing the member 210 from being pulled out.

  In particular, since the cord 121 is covered with a coating layer 122 formed of a mixture of a thermosetting resin and latex, the coating layer 122 and the rubber sheet 260 are bonded to each other, so that the sleeve 120 is prevented from being pulled out. high.

(6) Other Embodiments Although the contents of the present invention have been described with reference to the examples, the present invention is not limited to these descriptions, and various modifications and improvements are possible. It is obvious to the contractor.

  For example, in the above-described embodiment, the adhesive layer 240 is formed between the sleeve 120 and the folded portion 120a, or between the caulking member 230A and the sleeve 120 (Modification 2). The layer 240 is not necessarily formed.

  In the above-described embodiment, the rubber sheet 250 and the rubber sheet 260 are provided (Modification 1). However, at least one of the rubber sheets may not necessarily be provided.

  Although the embodiments of the present invention have been described as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

10 Fluid pressure actuator
20 Connecting part
100 Actuator body
110 tubes
120 sleeve
120a Folding part
121 code
122 Coating layer
200, 200A sealing mechanism
210, 210A Sealing member
211, 211A fuselage
213 Irregularities
214 1st small diameter part
215 Through hole
220 Locking ring
230, 230A Caulking member
231 Indentation
240 adhesive layer
250, 260 Rubber sheet
300 Sealing mechanism
400 fitting
410 passage hole

Claims (5)

A fluid pressure actuator comprising an actuator main body comprising a cylindrical tube that expands and contracts by the pressure of a fluid, and a sleeve woven with a cord oriented in a predetermined direction and covering the outer peripheral surface of the tube Because
The cord is composed of organic fibers,
Having a coating layer covering the surface of the cord;
The fluid pressure actuator, wherein the coating layer is formed of a mixture of a thermosetting resin and latex.   The said coating layer is formed using the aqueous mixture solution whose solid content rate (wt%) of the said thermosetting resin and the said latex is 15% or more and 50% or less. Fluid pressure actuator.   3. The fluid pressure actuator according to claim 1, wherein the thermosetting resin is a mixture of one or more of a phenol resin, a resorcin resin, and a urethane resin.   The fluid pressure actuator according to any one of claims 1 to 3, wherein the latex is one of VP latex, SBR latex, and NBR latex, or a mixture thereof. The fluid pressure actuator has a sealing member that seals an end of the actuator main body in the axial direction,
The fluid pressure actuator according to any one of claims 1 to 4, wherein the sealing member includes a rubber sheet that contacts the sleeve.

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