Actuator bending inner side length measuring device and actuator bending inner side length measuring method

Abstract

The present invention relates to a device for measuring the length on the inner side of bending of an actuator, which is a device for measuring the length on the inner side of bending of an actuator having a cylindrical actuator main body part in which one side of the cylinder circumference is shortened and bent by an increase in the internal pressure inside the cylinder, the base end side of the cylinder shaft of the fluid pressure actuator being fixed to a base body. The present invention relates to an actuator bending inside length measuring device, the tip of which moves relative to a base body, the actuator bending inside length measuring device comprising: a wire member, one end side of which is attached to the base body and the intermediate part of which is disposed on the bending side of an actuator main body part (22) so as to follow bending deformation; a wire holding member that holds the wire member at a position along the actuator main body; and a measuring unit that applies tension to the wire member and measures the amount of change in length of the wire member.

Description

Technical Field

[0001] The invention relates to a device for measuring the inner bending length of a fluid pressure actuator and a method for measuring the inner bending length of the actuator. Background Art

[0002] Conventionally, a McKibben-type fluid pressure actuator is known as a fluid pressure actuator having a rubber tube and a sleeve (a sleeve formed by weaving high-tensile fibers) covering the outer surface of the rubber tube. Such a McKibben-type fluid pressure actuator can change the axial length of the rubber tube and the sleeve.

[0003] In addition, a technology has been proposed in which a restraining member is partially provided in the circumferential direction from one end side to the other end side of the rubber tube in the axial direction, thereby shortening the side of the fluid pressure actuator where the restraining member is not provided and performing bending deformation (see Japanese Patent Publication No. 2021-88999). Summary of the invention

[0004] Problem that the invention aims to solve

[0005] Japanese Patent Application Publication No. 2021-88999 also proposes that such a fluid pressure actuator can be used as a finger that holds an object by bending and deforming by combining multiple fluid pressure actuators. In this case, it is necessary to find the length of the inner side of the bend based on the relationship with the force of holding the object by the fluid pressure actuator.

[0006] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide an actuator curved inner side length measuring device and an actuator curved inner side length measuring method that can easily determine the length of the curved inner side of a fluid pressure actuator.

[0007] Solutions for solving problems

[0008] In order to achieve the above-mentioned purpose, the actuator bending inner side length measuring device of the first technical scheme is an actuator bending inner side length measuring device for a fluid pressure actuator, wherein the fluid pressure actuator has a cylindrical main body portion whose side of the cylinder wall is shortened and bent in the cylinder axis direction due to the increase in internal pressure in the cylinder, the base end side of the cylinder axis of the fluid pressure actuator is fixed to the base, and the top end moves relative to the base, and the actuator bending inner side length measuring device comprises: a wire member, one end of which is mounted on the base, and the middle part is arranged on the curved side of the main body in a manner following the bending deformation; a wire holding member, which holds the wire member in a position along the main body; and a measuring part, which applies tension to the wire member and measures the length change of the wire member.

[0009] In the actuator bending inner side length measuring device of the first technical solution, the middle portion of the wire member is arranged on the curved side of the main body of the fluid pressure actuator in a manner that follows the bending deformation. By measuring the length change of the wire member using the measuring unit, the length of the curved inner side of the fluid pressure actuator can be easily measured even in a bent state.

[0010] In the actuator bending inner side length measuring device according to the second aspect, the other end side of the wire member is fixed to a position closer to the distal end side than the main body of the fluid pressure actuator.

[0011] By fixing the other end of the wire member to the top end of the fluid pressure actuator, the shortening of the main body is not hindered. In addition, since the wire member can be arranged from one end to the other end of the main body, the length of the inner side of the bend of the fluid pressure actuator can be measured with high accuracy.

[0012] In the actuator bending inner side length measuring device according to the third aspect, the wire holding member is formed of a flexible tube which is arranged along one side of the bending of the main body and along the cylinder axis direction and through which the wire member passes.

[0013] By forming the wire holding member from a flexible tube and arranging it along the curved side of the main body and the cylindrical axis direction, the wire member can be passed through and arranged along the curved side of the main body.

[0014] In the actuator bending inner side length measuring device according to the fourth aspect, one end of the flexible tube is fixed to the base, and the other end is fixed to a position closer to the distal end side than the main body of the fluid pressure actuator.

[0015] By fixing one end of the flexible tube to the base and the other end to the distal end of the main body of the fluid pressure actuator, the shortening of the main body is not hindered at the fixed position.

[0016] In the actuator bending inner side length measuring device according to the fifth aspect, the measuring section includes a rotary encoder that detects the winding length while winding the wire member.

[0017] In this way, the protruding length of the wire member from the base body can be easily measured using the rotary encoder.

[0018] The actuator bending inner side length measurement method of the sixth technical solution is an actuator bending inner side length measurement method for a fluid pressure actuator, wherein the fluid pressure actuator has a cylindrical main body portion whose one side of the cylinder circumference is shortened and bent due to an increase in the internal pressure in the cylinder, the base end side of the cylinder shaft of the fluid pressure actuator is fixed to a base, and the top end moves relative to the base. In the actuator bending inner side length measurement method, a wire member whose one end side is mounted on the base and whose middle portion is arranged along one side of the bending of the main body portion and the direction of the cylinder axis is maintained in a position along the main body portion, tension is applied to the wire member, and the length change of the wire member is measured.

[0019] In the actuator bending inner side length measurement method of the sixth technical solution, the middle portion of the wire member is arranged on the bending side of the main body of the fluid pressure actuator in a manner that follows the bending deformation. Therefore, by measuring the length change of the wire member, the length of the inner side of the bending of the fluid pressure actuator can be easily measured even in the bent state.

[0020] Effects of the Invention

[0021] According to the present disclosure, the length of the inner side of the bend of the fluid pressure actuator can be easily obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a side view of a fluid pressure actuator which is a measurement target of the actuator bending inner side length measuring device according to the present embodiment.

[0023] Figure 2 It is a partially exploded perspective view of a fluid pressure actuator.

[0024] Figure 3 is a cross-sectional view of a fluid pressure actuator.

[0025] Figure 4 This is a diagram showing a state (non-bending state) in which a fluid pressure actuator is mounted on the actuator bending inner side length measuring device.

[0026] Figure 5 This is a diagram showing a state (bent state) in which a fluid pressure actuator is mounted on the actuator bent inner side length measuring device. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments for realizing the technology of the present disclosure will be described in detail with reference to the drawings.

[0028] In addition, in all the drawings, the same reference numerals are given to components and processes having the same role and function, and repeated descriptions may be appropriately omitted. In addition, the present disclosure is not limited to the following embodiments, and can be implemented by appropriately adding changes within the scope of the purpose of the present disclosure.

[0029] <Structure of Fluid Pressure Actuator>

[0030] exist Figure 1 2 shows a fluid pressure actuator 20 to be measured by the actuator bending inner side length measuring device 10 of the present disclosure. The fluid pressure actuator 20 includes an actuator body 22 and sealing members 30A and 30B.

[0031] Also like Figure 2 As shown, the actuator body 22 has a tube 24, a sleeve 26 and a restraining member 28. The tube 24 is a cylindrical shape that can be expanded and contracted by elastic deformation, and expands and contracts according to the pressure change of the internal fluid. The axial direction of the tube 24 is set to "axial 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 an air actuator. In addition, when the fluid pressure actuator 20 is set to hydraulic drive, 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 epichlorohydrin rubber.

[0032] The sleeve 26 is formed into a cylindrical shape covering the outer circumference of the tube 24. The sleeve 26 is a stretchable structure formed by weaving fiber cords oriented in a predetermined direction, and the oriented cords intersect the axial direction S at a predetermined angle θ. By having such a shape, the sleeve 26 deforms like a change in the expansion and contraction of the tube 24, and follows the contraction and expansion while restricting the contraction and expansion.

[0033] 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.

[0034] The restraining member 28 is provided between the tube 24 and the sleeve 26. The restraining member 28 is provided in a long plate shape, and its longitudinal direction is arranged along the axial direction of the tube 24, covers part of the outer circumference of the tube 24, and is arranged from one end of the tube 24 to the other end.

[0035] The restraining member 28 is formed of a material that does not expand or contract due to pressure, and can bend and deform in the direction in which the ends are close to each other. As the restraining member 28, a so-called leaf spring can be used. The size of the leaf spring is determined according to 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, but typically, it can be a material such as stainless steel or other metal that is easy to bend and deform and has a strong compression resistance. In addition, it can also be formed by a thin plate of carbon fiber reinforced plastic (CFRP) or the like.

[0036] The sealing member 30A includes a sealing connector 32 , a locking ring 34 , and a caulking member 36 .

[0037] The sealing connector 32 has an integrally formed cover portion 32A and an insertion portion 32B. The cover portion 32A is formed into a hexagonal prism having a diameter larger than the outer diameter of the tube 24, and the insertion portion 32B is formed extending from the center of one end side of the cover portion 32A along the axial direction S. The insertion portion 32B is set in a so-called bamboo shoot shape and inserted into one end side of the tube 24 on the inner side of the sleeve 26. A mounting portion 33 is formed on the side of the cover portion 32A opposite to the insertion portion 32B. A mounting hole 33A is formed in the mounting portion 33 that passes through in a direction orthogonal to the axial direction S. As the sealing member 30A, metals such as stainless steel can be suitably used, but are not limited to such metals, and hard plastic materials can also be used.

[0038] like Figure 3 As shown, the sealed connector 32 has a flow path R. The flow path R is formed in the radial center of the insertion portion 32B and extends in the axial direction, and communicates with the connection hole H on the side of the cover portion 32A. The air supply hose 50 (see Figure 4 ), supplied with compressed air.

[0039] The locking ring 34 is annular and is disposed outside the sleeve 26 so as to sandwich the sleeve 26 between the locking ring 34 and the insertion portion 32B, locking the sleeve 26 to the sealed connector 32. The sleeve 26 is folded back 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.

[0040] The caulking 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 caulks the actuator body 22 to the sealed connector 32. Thus, the actuator body 22 is fixed to the sealed connector 32. As the caulking member 36, a metal such as aluminum alloy, brass, and iron can be used.

[0041] The sealing member 30B has the same sealing connector 32, locking ring 34 and caulking member 36 as the sealing member 30A. However, the sealing connector 32 does not have a connection hole H and a flow path R, and its tip is R-shaped.

[0042] <Operation of Fluid Pressure Actuator>

[0043] like Figure 4 As shown, the fluid pressure actuator 20 is used in a manner in which the sealing member 30A at one end side is fixed and the sealing member 30B at the other end side is a free end.

[0044] When compressed air flows into the connection hole H via the air supply hose 50, the pressure in the fluid pressure actuator 20 increases. As the internal pressure increases, the tube 24 elastically deforms and expands, and the sleeve 26 deforms in such a way that the angle θ becomes larger, and a force is applied in the direction of shortening the length L0 (the length when not shortened) of the actuator body 22. At this time, since the outer peripheral side wall of the actuator body 22 on which the restraining member 28 is arranged is restricted from shortening, 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 (hereinafter referred to as the "bent inner wall 22A") is shortened. As a result, the restraining member 28 is flexed and deformed, as shown in FIG. Figure 5 As shown, the entirety of the actuator body portion 22 is bent.

[0045] In this way, the force acting on the sealing member 30B in the direction perpendicular to the axial direction S (hereinafter referred to as “axis-perpendicular direction X”) when the actuator body 22 is bent is referred to as the holding force F.

[0046] <Actuator bending inner side length measurement device>

[0047] like Figure 4 As shown, the actuator bending inner side length measuring device 10 includes a base 12 , a wire winding portion 14 , a measuring portion 15 , a wire member 16 , a wire holding member 18 , a counter board 40 , and a controller 44 .

[0048] The base 12 includes a base portion 12A, a column portion 12B extending upward from the base portion 12A, and a support portion 12C protruding horizontally from the upper end of the column portion 12B. A sealing member 30A of the fluid pressure actuator 20 is fixed to the lower surface of the support portion 12C via a mounting portion 33. An air supply hose 50 is connected to a connection hole H of the sealing member 30A.

[0049] The wire winding section 14 is provided on the support section 12C and is rotatable about the winding axis M. The wire winding section 14 acts a force to wind up the other end side of the wire member 16 so that the wire member 16 cannot be loosened. This force is set to be smaller than the restoring force of restoring from the bent state to the straight state by returning the pressure in the fluid pressure actuator 20 to the atmospheric pressure.

[0050] The other end of the wire member 16 is fixed to the position (the curved inner wall 22A side) on the outer periphery of the sealing member 30B opposite to the restraining member 28 by a fixing member 31C. One end of the wire member 16 is mounted on the wire winding portion 14. The wire member 16 is formed of a long wire material that can be wound, and a metallic cord, fiber, or other wire can be used. The wire member 16 is inserted into the wire holding member 18 from the other end to just before being wound on the wire winding portion 14.

[0051] The wire holding member 18 is configured in a tubular shape and is disposed at a position (on the curved inner wall 22A side) on the outer periphery of the sealing member 30B opposite to the restraining member 28. The wire holding member 18 is configured to cover the length from one end to the other end of the actuator body 22 in a non-compressed state (longer than the actuator body 22). The wire holding member 18 is configured along the axial direction S. A flexible tube can be used as the wire holding member 18. The top end of the wire holding member 18 is fixed to the fixing portion 31C.

[0052] A locking portion 31A is formed at a position in the sealing member 30A corresponding to the curved inner wall 22A side in the circumferential direction. The locking portion 31A has a hole 31B opened in the axial direction S through which the wire holding member 18 can pass, and the wire member 16 passes through the hole 31B. The locking portion 31 is used to allow the wire holding member 18 to move relative to the sealing member 30A in the axial direction S and to restrict the movement of the wire holding member 18 relative to the sealing member 30A in the circumferential and radial directions. In addition, relative movement of the wire holding member 18 and the sealing member 30A is allowed in the axial direction S. Thus, the wire holding member 18 is arranged along the curved inner wall 22A of the actuator body 22 from one end to the other end, following the movement of the actuator body 22.

[0053] The measuring unit 15 is formed of a rotary encoder that detects a signal according to the rotation of the wire winding unit 14 around the winding axis M, and sends the detection signal to the counter board 40. The counter board 40 counts the signal sent from the measuring unit 15 to obtain the winding length LR of the wire member 16.

[0054] Here, the action of the fluid pressure actuator 20 and the length L1 of the curved inner wall 22A are explained. The length L1 of the curved inner wall 22A is the length L0 when the fluid pressure actuator 20 is in a non-bent state, and is shortened when the pressure in the fluid pressure actuator 20 rises. Due to this shortening, the wire member 16 arranged along the curved inner wall 22A is wound up by the wire winding portion 14 and cannot be relaxed. The other end side of the wire member 16 is fixed to the curved inner wall 22A side of the top end (sealing member 30B) of the fluid pressure actuator 20, and one end side of the wire member 16 is mounted on the wire winding portion 14. Therefore, the protruding length of the wire member 16 from the wire winding portion 14 can be measured based on the winding rotation of the wire member 16 by the wire winding portion 14.

[0055] Since the wire member 16 passes through the wire holding member 18 and is arranged along the curved inner wall 22A of the actuator body 22, the length change of the wire member 16, that is, the winding length LR, is substantially the same as the shortened length of the actuator body 22. Therefore, the length L1 of the curved inner wall 22A is obtained by subtracting the winding length LR of the wire member 16 from the length L0 when the actuator body 22 is in the non-bent state. By subtracting the length LR from the length L0, the length L1 of the curved inner wall 22A can be calculated.

[0056] The winding length LR output from the counter board 40 is processed by the controller 44, and the length L1 can be obtained by subtracting the length LR from the pre-stored length L0. The controller 44 has a CPU, ROM, RAM, input / output interface (I / O), storage unit, etc. (not shown), and outputs the obtained length L1 as required. The output can be displayed on a display unit or can be an output for feedback for subsequent processing.

[0057] In the actuator bending inner side length measuring device 10 of the present embodiment, the wire member 16 is arranged to follow the bending deformation of the bending inner side wall 22A of the actuator body 22 of the fluid pressure actuator 20 by using the wire holding member 18. Therefore, by measuring the length change amount of the wire member 16, that is, the length LR, the length of the bending inner side of the fluid pressure actuator 20 can be easily measured even in the bent state.

[0058] In addition, in the present embodiment, the other end side of the wire member 16 is fixed to the curved inner side wall 22A at a position closer to the tip side than the actuator body 22, but it may be arranged in the middle part of the actuator body 22 by other members in a manner not to hinder the bending of the actuator body 22. In this case, the relationship between the winding length LR of the wire member 16 and the length L1 can be measured in advance, and a correspondence table can be prepared to obtain the length L1.

[0059] In addition, in the present embodiment, the wire member 16 is arranged along the curved inner wall 22A of the actuator body 22, but it may be arranged along a position where the outer circumference of the actuator body 22 is shortened. In this case, the relationship between the winding length LR of the wire member 16 and the length L1 can be measured in advance, and a correspondence table can be prepared to obtain the length L1.

[0060] The disclosure of Japanese Patent Application No. 2022-140034 filed on September 2, 2022 is incorporated herein by reference in its entirety.

[0061] All documents, invention patent applications, and technical specifications described in this specification are incorporated into this specification by reference to the same extent as if each document, invention patent application, and technical specification were specifically and separately described.

Claims

1. A device for measuring the inner length of an actuator bending, wherein: The actuator bending inner side length measuring device is an actuator bending inner side length measuring device for a fluid pressure actuator, wherein the fluid pressure actuator has a cylindrical main body portion whose side of the cylinder wall is shortened and bent in the cylinder axis direction due to the increase of the internal pressure in the cylinder, and the base end side of the cylinder axis of the fluid pressure actuator is fixed to a base body, and the top end moves relative to the base body. The actuator bending inner side length measuring device comprises: a wire member, one end of which is mounted on the base, and a middle portion of which is arranged on one side of the bend of the main body so as to follow the bending deformation; a wire retaining member that retains the wire member in position along the main body portion; and The measuring unit applies tension to the wire member and measures a length change of the wire member.

2. The actuator bending inner side length measuring device according to claim 1, wherein: The other end side of the wire member is fixed to a position closer to the distal end side than the main body of the fluid pressure actuator.

3. The actuator bending inner side length measuring device according to claim 1, wherein: The wire holding member is formed of a flexible tube that is arranged along one side of the curve of the main body and along the cylinder axis direction and through which the wire member passes.

4. The actuator bending inner side length measuring device according to claim 3, wherein: One end of the flexible tube is fixed to the base, and the other end is fixed to a position closer to the distal end side than the main body of the fluid pressure actuator.

5. The actuator bending inner side length measuring device according to any one of claims 1 to 4, wherein: The measuring section includes a rotary encoder that detects a winding length while winding the wire member.

6. A method for measuring the inner length of an actuator bending, wherein: The actuator bending inner length measuring method is an actuator bending inner length measuring method for a fluid pressure actuator, wherein the fluid pressure actuator has a cylindrical main body portion whose one side of the cylinder is shortened and bent due to the increase of the internal pressure in the cylinder, and the base end side of the cylinder shaft of the fluid pressure actuator is fixed to a base body, and the top end moves relative to the base body. In the actuator bending inner length measurement method, A wire member having one end attached to the base and an intermediate portion arranged along one side of the curvature of the main body and along the cylindrical axis is held at a position along the main body, A tension is applied to the wire member, and a change in length of the wire member is measured.

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