JPH0445318B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field Developed for use in storage, refilling, distribution, and other experiments and processing of radioactive materials through the shielding wall of a so-called hot cell, which is surrounded by a protective wall from radioactive contamination. With the development of robotic technology, the manipulators (magic hands) that were first developed have been used in a wide range of applications, including the replacement of manual labor, and their use has expanded dramatically.

The following discussion regarding improvements in particularly suitable actuators as operating parts of such manipulators or the like is located in the field of robotics technology.

Prior Art and its Problems There are various types of actuators for the 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, the air bag type is also known, and in this case, the axial contraction force based on the expansion diameter of the air bag by applying control pressure is used as the operating force, so the air bag itself is lightweight and does not include any sliding parts. Advantages are recognized, such as there is no need to worry about the effects of frictional force or air leakage.

This air bag type new automatic
As an actuator, for example, one as shown in FIG. 1 is known in the art as described in Japanese Patent Publication No. 52-40378.

In FIG. 1, 1 is a tubular body, 2 is a braided reinforcing structure formed by reinforcing cords around its 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 reinforcement structure 2 using reinforcing cords conforms to the customary use in pressure-resistant rubber hoses, for example, but in that case, the braid angle is close to the so-called rest angle (54° 44'), whereas the internal pressure filling of the tubular body 1 is The use conditions are determined so that the above-mentioned rest angle is reached at the maximum expansion diameter according to the above, preferably the initial value θ ₀ of the braid angle is about 20°, and the normal strain ε is about 0.3.

The reinforcing cord used for this braided reinforced structure 2 is suitable for 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. do.

Although the braiding operation on the outer periphery of the tubular body 1 is not necessarily easy under a considerably low angular arrangement such as the above initial value of 20°, for example, the braided body obtained by a normal rubber hose braiding machine can be used at the above initial value. When it is stretched in the axial direction so as to fit, and is placed over the outer periphery of the tubular body 1,
It is simple, and 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.

The closing member 3 is tightly attached to both end openings of the tubular body 1.
It consists of a nipple 5 for sealing and bonding, preferably using an adhesive, a flange 6 for positioning, and an eye or clevis end 7 with a connecting pin hole. It is possible to provide an annular protrusion 8 for preventing slippage, which forms a gentle taper in the opposite direction together with a sharp taper in the opposite direction. One of the closing members 3 is bored, at least on one side, with a connecting hole 11 which communicates with the internal cavity 10 of the tubular body 1 through a hole 9 formed in the longitudinal direction of the nipple 5, in which a fitting 12 is mounted.

The caulking cap 4 engages with the flange 6 and covers the outer periphery of the end of the tubular body 1, and is made of a cylindrical metal piece with a flare 13 formed on the edge, and is locally pressed in the radial direction toward the nipple 5 to close it. Part 3
is sealed and bonded to the tubular body 1. In the figure, numeral 14 illustrates an indentation made by a caulking tool.

An operating pressure source (not shown), such as an air compressor, is connected to the fitting 10 by a conduit including a three-way valve, and the braided structure 2 is controlled by applying a controlled pressure within the internal cavity 13 of the tubular body 1.
The expansion of the braiding angle θ ₀ to _θ , this contraction force F is expressed by the following formula 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 restores and expands 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.

Conventionally, the braided reinforcement structure 2 generally has a reinforcing cord embedded near the outer surface of a tubular body made of a rubber-like elastic material and is also firmly joined to the tubular body. Since the reinforcing cord tends to be restrained by the rubber-like elastic body and the contractile force is weakened, it is preferable to separate the reinforcing cord from the tubular body so that the reinforcing cord can move freely. However, when creating a structure in which the reinforcing cord is separated from the tubular body, other problems arise. That is, as shown in Fig. 2, the reinforcing cord is generally a twisted or untwisted bundle of many thin filament yarns 15 with a thickness of 0.02 to 0.03 mm, so that the tubular body made of elastic material expands. When the braiding angle changes greatly, the thin filament threads bite into the surface of the elastic tubular body, and the filament threads bite into the surface of the tubular body, similar to when scratched with a very sharp knife. There is a problem that it may damage the material and cause breakage.

OBJECT OF THE INVENTION The present invention aims to solve the above-mentioned problems in the conventional pneumatic actuator.

Structure of the Invention According to this invention, in order to achieve the above object,
A braided structure of reinforcing cords of organic or inorganic high tensile strength fibers is mounted around a tubular body of rubber or elastomer-like material, and closure members are sealed at the open ends of the tubular body, at least one of the closure members. In a pneumatic actuator in which a connecting hole is provided for communicating an external pressure air source with an internal cavity of a tubular body, the reinforcing cord constituting the braided structure is a large diameter single wire having a smooth rounded outer circumferential surface. It is characterized by

The single-wire reinforcing cord having a smooth rounded outer circumferential surface constituting the braided structure according to the present invention may be a monofilament yarn having a circular cross section as shown in FIG. A steel wire 16, as shown in FIG. 4, having a circular cross-section of a diameter similar to that shown in FIG.
As shown in FIG. 1, a twisted or untwisted bundle 17 of a large number of filament yarns 15 is coated with a rubber-like elastic material or a synthetic resin. Alternatively, as shown in FIG. These reinforcing cords have a smooth surface, make the contact surface with the surface of the tubular body of the elastic material an obtuse angle, and increase the contact surface area to reduce the contact surface pressure. By blunting the sharpness of the thread, damage to the tubular body caused by the reinforcing cord can be significantly reduced.

According to this invention, the polyester diameter 0.4mm
A braided structure with a driving density of 90% is made of a reinforcing cord made of monofilament yarn and a reinforcing cord made by twisting filament yarns with a diameter of 0.02 mm x 44 x 3. A durability test was conducted using a pneumatic actuator attached around a tubular rubber hose. During this test, the working fluid air was 2 kg.
→ Pressure is changed to 0 in one cycle per second, 1Kg
A hanging load was applied. As a result of the test, the conventional one broke after 13,600 cycles, but the one according to the present invention broke after 67,000 cycles.

Effects of the Invention As described above, according to the present invention, the reinforcing cord constituting the braided structure is a large-diameter single-wire cord having a smooth rounded outer circumferential surface.
Reduces the contact pressure between the elastic material and the surface of the tubular body, reducing damage to the tubular body due to reinforcement cords,
The life of the tubular body can be improved by two to several times.

[Brief explanation of drawings]

FIG. 1 is a front view showing a part of an air bag type pneumatic actuator in cross section;
FIG. 2 is a sectional view of a reinforcing cord constituting the braided structure of a conventional pneumatic actuator, and FIGS. 3 to 5 show various aspects of the reinforcing cord constituting the braided structure according to the present invention. FIG. 1... Tubular body, 2... Braided reinforcement structure, 3...
... Closing member, 9 ... Connection hole, 10 ... Internal cavity,
16, 18, 19... Reinforcement cord.

Claims (1)

[Claims] 1 A braided structure of reinforcing cords of organic or inorganic high tensile strength fibers is attached around a tubular body of rubber or rubber-like elastic material, and closure members are sealed at both end openings of the tubular body, and at least one of the closures is closed. In a pneumatic actuator in which a member is provided with a connection hole for communicating an external pressure air source with an internal cavity of a tubular body, the reinforcing cord constituting the braided structure is a large-diameter solid wire having a smooth rounded outer circumferential surface. A pneumatic actuator characterized by having a shape.