JPH05562B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) For storage, refilling, distribution, and other operations of radioactive materials through the shielding wall of a so-called hot cell surrounded by a protective wall from radioactive contamination during experiments and processing. The manipulator (magic hand) that was developed for this purpose has since expanded into a wide range of applications, including the replacement of manual labor, due to the development of robotics technology.

The following discussion regarding improvements in particularly suitable actuators as operating parts of such manipulators or similar devices lies in the field of robotics technology.

(Prior Art) There are various types of actuators for manipulators installed in the above-mentioned hot cells, but since sparks are unavoidable with motors, especially electric ones, pneumatic types are preferably used when explosion-proofing is required. Of course, it can be used for general purposes.

Conventional pneumatic actuators are often of the so-called air cylinder type, but the cylinder-piston assembly is usually made of iron, so its own weight as an operating part is excessive compared to the operating force. I don't like it.

On the other hand, air bag types are also known, in which case it is particularly advantageous to use the axial contraction force due to the expansion diameter of the air bag by applying a controlled pressure as the operating force, and here the air bag itself is lightweight. In addition, since there are no sliding parts, it is not affected by frictional force and there is no need to worry about air leakage. However, the amount of air sealed when applying the pressure is smaller than that of an air cylinder, which reduces the expansion of the air bag. Since the internal volume increases due to the diameter, the amount of air used is quite large, which is disadvantageous in terms of the amount of air used for operation, which is dissipated into the atmosphere when released.

Furthermore, since the control pressure acts on the entire surface of the internal cavity surrounding wall within the air bag, at least at the initial stage of operation of the air bag, the drag force represented by the product of the cross-sectional area perpendicular to the axial direction, that is, the axial pressure-receiving area and the control pressure, is Another disadvantage is that it reduces the effective axial retraction force.

(Problems to be Solved by the Invention) It is possible to propose an improved pneumatic actuator that can overcome the above-mentioned disadvantages without hindering the advantages of the air bag type pneumatic actuator. , which is the object of this invention.

(Means for Solving the Problems) The above objectives are advantageously satisfied by a configuration that has the following points as its main points.

A braided structure using organic or inorganic high tensile strength fibers as a tensile reinforcing element, the outer periphery of the braided structure reinforced, and openings at both ends sealed at least on one side by a pair of closing members each having a connecting hole. A tubular body made of rubber or a rubber-like elastic material, capable of expanding and contracting in the axial direction within the internal cavity of the tubular body between the above-mentioned both end closing members, having an outer diameter equivalent to the inner diameter of the cavity, and having high external pressure resistance. , and a pleated membrane tube, which generates an axial contraction force during expansion and diameter deformation based on injection of pressure medium into the internal cavity of the tubular body through the connection hole. A pneumatic actuator.

(Function) According to the above configuration, the outer periphery is reinforced with a braided structure using organic or inorganic high tensile strength fibers as a tensile reinforcement element, and the openings at both ends are sealed with a closing member. Based on the application of a controlled pressure to the inside of the tubular body, that is, the air bag, by a pressure source connected via piping to a connecting hole provided in the closing member, the axial direction is caused by expansion and diameter deformation accompanied by pantograph movement of the above-mentioned braided structure. It is of course possible to generate a contractile force, since the internal cavity of the tubular body to which this control pressure is applied is occupied in the present invention by a particularly pleated membrane tube. The reduction in air usage corresponding to the total volume is achieved as follows.

In other words, the total internal volume V of the tubular body is determined by the following formula: V=π/4d ² (sin ² θ _x /sin ² θ ₀・cos θ _x /cos θ ₀ )
l...(1) where d: Internal diameter of the tubular body l: Effective length of the tubular body θ ₀ : Braid angle (initial value) θ _x : Braid angle (when expanded) It is given by, and the contraction rate ε is , as shown by the following formula ε=cosθ ₀ −cosθ _x /cosθ ₀ ...(2) Therefore, a pleated membrane tube with high resistance to external pressure and having an outer diameter approximately equal to the inner diameter of the inner cavity of the tubular body is placed. Then, the occupied volume v is expressed by the following formula v=π/4d ² (1−ε)l (3), and therefore, the space to which the control pressure is applied in the tubular body equipped with this membrane tube according to the present invention is The internal volume V _c is
The following formula V _c = π/4d ² {sin ² θ _x /sin ² θ ₀・cosθ _x /cosθ ₀ −(
1-ε)}l...(4) Therefore, the ratio of this internal volume V _c to the total internal volume V, that is, the air consumption per operation in this invention compared to the conventional air bag type actuator. The ratio f _e is calculated as follows.

f _e =V _c /V=sin ² θ _x /sin ² θ ₀・cosθ _x /cosθ ₀ −(1
−ε) /sin ² θ _x /sin ² θ ₀・cosθ _x /cosθ ₀ ...(5) Here, according to the formula (2), cosθ _x = (1−ε)cosθ ₀ ,
Therefore, equation (5) is f _e = sin ² θ _x cosθ _x −(1−ε) sin ² θ ₀ cosθ ₀ /sin ²
θ _x・cosθ _x = (1−cos ² θ _x )cosθ _x −(1−ε) sin ²
θ ₀ cosθ ₀ / (1−cos ² θ _x )cosθ _x = {1−(1−ε) ² cos ² θ ₀ }(1−ε) cosθ ₀ −(
1−ε) sin ² θ ₀ cosθ ₀ {1−(1−ε) ² cos ² θ ₀ }(
1-ε)
cosθ ₀ = (1-ε) [{1-(1-ε) ² cos ² θ ₀ } cosθ ₀ −
sin ² θ ₀ cosθ ₀ ] {1-(1-ε) ² cos ² θ ₀ }(1-ε
) cosθ ₀
...(6) can be arranged as follows.

According to this result, for example, when the initial value of the braid angle is 20°, if ε is set to approximately 0.3, the amount of air used per actuator operation will be approximately 10% compared to an air bag that does not use a pleated membrane tube.
This results in savings of more than a certain amount, and the effect of suppressing the total air consumption during frequent operations is significant.

In addition, since the pleated membrane tube has no control pressure acting on its inside, there is no contraction resistance based on the control pressure whose cross-sectional area is the pressure-receiving area, and the contraction force of the tubular body can be used for work more effectively. Available.

(Embodiment) Now, FIG. 1 shows a pneumatic system according to the present invention.
A cross section of the main parts of the actuator is shown along with the front appearance. In the figure, 1 is a tubular body, 2 is a braided reinforcement structure on the outer periphery, 3 is a closing member at both ends, and 4 is a caulking cap.

For the tubular body 1, rubber or rubber-like elastic material can be usefully used in terms of air impermeability and flexibility.
Equivalent materials such as various plastics may be substituted.

The braided reinforcing body 2 conforms to the customary use in pressure-resistant rubber hoses, for example, but in that case, the braiding angle is close to the so-called rest angle (54° 44'), whereas the maximum expansion diameter due to internal pressure filling of the tubular body 1 is the above-mentioned. In order to reach the rest angle, preferably the initial value of the braid angle θ _is set to about 20°, and the normal strain ε is approximately 0.3.
Conditions of use shall be established to ensure the appropriate level of use.

The tensile strength reinforcing element used in this braided reinforced structure 2 is made of organic or inorganic high tensile strength fibers, such as aromatic polyamide fibers (Kepler: trade name), twisted or untwisted bundles of filaments such as ultrafine metal wires, etc. Compatible.

Although the braiding operation on the outer periphery of the tubular body 1 is not necessarily easy under a considerably low angle arrangement such as the initial value of 20°, for example, a braided body obtained with a normal rubber hose braiding machine can be adjusted to the above initial value. It is convenient to fit it over the outer periphery of the tubular body 1 while being stretched in the axial direction. At this time, adhesive may be applied to the outer periphery of the tubular body 1 as appropriate.

Further, the outer periphery of the braided reinforced structure 2 may be provided with a weather-resistant and trauma-resistant protective coating as appropriate.

A pair of closure members 3 fitted at both ends of the tubular body 1 are
Nipples 5 are provided at both ends of the tubular body 1 for sealing tightly, preferably using an adhesive.
Its position is determined by a flange 6, and an eye or clevis end 7 with a connecting pin hole, and the outer periphery of the nipple 5 is formed with a gentle taper toward its tip and a sharp taper in the opposite direction. , it is possible to provide a tubular protrusion 8 for preventing slippage. At least one of the pairs of closure members 3 is provided with a connecting hole 9 communicating with the internal cavity of the tubular body 1 through the central hole of the nipple 5, as shown, and a fitting 10 is attached thereto.

The caulking cap 4 engages with the flange 6 and covers the outer periphery of the end of the tubular body 1. The caulking cap 4 is made of a cylindrical metal piece with a flare 11 formed on the edge, and is locally pressed in the radial direction toward the nibble 5 to close it. Part 3
The tubular body is tightly sealed against. In the figure, numeral 12 illustrates an indentation made by a caulking tool.

In this example, as an example of a pleated membrane tube 13 fixed with adhesive at the tip of the nipple 5, a bellows is extended between the closing members 3 and 3 at both ends, and the center hole of the nipple 5 is attached to the body wall closed with a plug 14. Vent hole 15
is opened, and the inner periphery of the tubular body 1 and the bellows 13
Open the gap between the outer periphery of the

The pleated membrane tube 13 shown in the bellows example can easily expand and contract in the axial direction, but has high external pressure resistance,
It is necessary that no crushing deformation occurs under controlled pressure, and for this reason, it is desirable to provide ring reinforcement on the outer periphery of the valleys of the pleats and the inner periphery of the crests of the pleats (not shown).

Further, in the closing member 3 on the side where the fitting 10 is not provided, the inside of the pleated membrane tube 13 may be communicated with the atmosphere through the central hole of the nipple 5.

The pleated membrane tube 13 is not limited to bellows, but may also be made flexible by telescopically connecting thin-walled rigid tubes 17, 17' connected by a so-called bellows frame 16, as shown in FIG.

The braiding of the braided structure 2 is performed by connecting an operating pressure source (not shown) to the fitting 10, such as an air compressor, to a conduit containing a three-way valve and applying a controlled pressure within the internal cavity of the tubular body 1. Angle θ ₀
In other words, due to the pantograph movement, the expansion diameter of the tubular body 1 is expanded to _θ , the following equation is given by

On the other hand, upon release of the control pressure, the air in the internal cavity is dissipated into the atmosphere through the three-way valve, and the tubular body 1 is restored and elongated as the braid angle θ _x of the braided reinforcement structure 2 decreases. Needless to say.

Therefore, such a pneumatic actuator can, for example, perform a pin connection between the articulated actuating arms through the eyes or clevises 7 of the closing member 3 at both ends to guide bending, extension, and joint movements between the actuating arms. It's obvious.

(Effects of the Invention) As described in detail above, the pneumatic actuator of the present invention falls into the category of air bag type actuators, and although it is easier to control operating force and compliance than conventional air bag type actuators, Conventionally, the increase in internal volume due to the expanded diameter is more than twice that of the air cylinder type, so the amount of operating air used was excessive. The incorporation of space-occupying pleated membrane tubes provides virtually no drag that counteracts the axial retraction force, thereby providing significant relief without compromising the advantages of air bag actuators.

[Brief explanation of the drawing]

FIG. 1 is a sectional front view of a main part showing an embodiment of the present invention, and FIG. 2 is a sectional view of another example of a pleated membrane tube. 1... Tubular body, 2... Braided reinforcement structure, 3...
Closing member, 9... connection hole, 13... pleated membrane tube.

Claims (1)

[Scope of Claims] 1. A braided structure using organic or inorganic high tensile strength fibers as a tensile reinforcement element, and a closing member whose outer periphery is reinforced by this braided structure and has openings at both ends and a connection hole on at least one side. a tubular body made of rubber or rubber-like elastic material sealed by a pair of the tubular bodies, and having an outer diameter equivalent to the inner diameter of the cavity, which is expandable and contractible in the axial direction between the end closing members within the inner cavity of the tubular body; and a pleated membrane tube with high resistance to external pressure, during expansion and diameter deformation due to the injection of pressure medium into the internal cavity of the tubular body through the connection hole, the axial direction A pneumatic actuator characterized by generating a contractile force of. 2. The actuator according to claim 1, wherein the pleated membrane tube has ring reinforcements on the outer periphery of the valleys of the pleats and the inner periphery of the crests of the pleats.