JPS60139904A - Pnuematic actuator - Google Patents

Abstract

PURPOSE:To improve the durability of a pneumatic actuator which comprises an internal cylinder made of an elastic material and a braided body covering the outside of the internal cylinder, by arranging a middle layer formed by braiding a fiber having a prescribed streching modulus between the internal cylinder and a braided body. CONSTITUTION:Air-back type pneumatic actuator which works mainly as the operational force of a robot has an internal cylinder 1 made of rubber or rubber- like elastic material and a braided body 2 covering the outside of the internal cylinder 1. Then a middle layer 14 which is formed by braiding a fiber and has a stretching modulus per unit width of 1-5X10<8>g/cm when it is stretched by 50% is fixed between the internal cylinder 1 and the braided body 2. The tensile elongation of the middle layer 14 when fractured is set at a value larger than 55%. Thus by protecting the internal cylinder 1 from the braided body 2 using the middle layer 14, the expansion and bending life of the internal cylinder 1 is improved and as a result, the life of the actuator is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an airbag type pneumatic actuator that mainly operates as an operating force for a robot. The present invention relates to a pneumatic actuator which has an excellent two-life durability and has a fiber knitted fabric as an intermediate layer between it and a covering braided structure.

In recent years, the TL manipulator (Magic Hand) was developed for the purpose of protection from dangerous work, but with the subsequent development of robot technology and the idea of energy saving and high productivity, it has expanded to a wide range of applications, including replacing manual work. As is well known, this is happening.

It is no exaggeration to say that for the development of such robot technology, the key point is how to obtain an excellent actuator as an operating part of a manipulator or similar. In fact, various actuators for manipulators have been proposed and put into practical use, but each of them has some problems. Therefore, the applicant has previously developed a new airbag-type pneumatic actuator that improves these problems and has filed a patent application (Japanese Patent Application No. 158-71,404;
-160.544). This air bag type pneumatic actuator consists of an inner cylinder as a tubular member made of rubber or rubber-like elastic material, and a braided structure covering the outer circumference of this inner cylinder and covering the outer circumference of the inner cylinder by 2 inches. When pressure is applied, the braided structure expands in the radial direction due to pantograph movement, and then contracts in the axial direction.
The contractile force generated at this time is used to move a member or device connected to the actuator (for example, a joint of a robot). In this case, make sure that no resistance force is generated against the change in the diameter of the inner cylinder. Therefore, the braided structure and the inner cylinder are not combined.

FIG. 1 shows such an air bag type pneumatic actuator.

In FIG. 1, 1 is a tubular body made of rubber or a rubber-like elastic body, 2 is a □' daughter tI4 □ set structure □ body provided on its outer periphery,
8 is a closing member at both ends, and 4 is a closed member. The nipple 5 consists of a nipple 5 used for sealing and joining, a flange 6 for positioning, and an eye or clevis end 7 with a connecting pin hole.The outer periphery of the nipple 5 has a gentle taper toward its tip. It is also possible to provide an annular protrusion 8 with a steep taper in the opposite direction forming a 2" shape for preventing removal. One of the closure members 8 is bored, at least on one side, with a connecting hole 11 communicating with the internal cavity 10 of the tubular body 1 via a hole 9 formed in the lengthwise 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. The caulking cap 4 is made of a cylindrical metal piece with a flare 18 formed on the edge, and is locally pressed in the radial direction toward the nipple 5. The closing member 8 is sealingly bonded to the tubular body 1 by using the following steps.

A near compressor as an external operating pressure source is connected to the pneumatic actuator having such a structure through a pipe line including an eight-way valve, and a control pressure is applied to the internal cavity 10 of the tubular body '1. , the expansion of the braided structure 2 from the angle θ to θ-, that is, due to the pantograph movement: This results in a reduction in the distance between the connecting bottle holes.

By the way, in the case of a pneumatic actuator with such a structure, when both ends of the actuator are sealed and a certain pressure is applied to the internal space, the external braided structure expands in the radial direction and contracts in one direction due to the axial force. It is said that the fibers or cords that make up the actuator get stuck in the inner cylinder made of rubber or rubber-like elastic material and damage the inner cylinder, which significantly shortens the life of the inner cylinder and, in turn, the five-year life of the pneumatic actuator. There was a problem.

As a result of conducting research based on the above problems, we created 10 intermediate layers made of knitted fibers between the inner tube made of rubber or rubber-like elastic material and the braided structure covering the outer periphery of the inner tube. As a result, it was possible to obtain a pneumatic actuator with extremely excellent durability without impairing the functions of conventional pneumatic actuators. Of course, 1S is based on the premise that the intermediate layer, which is the center of the present invention, has the following functions6. (1) It is so soft that it cannot prevent the expansion and contraction movement of the inner cylinder made of rubber or rubber-like elastic material, and it can stretch well. , (II)
The intermediate layer itself has excellent durability.

Therefore, the middle class that satisfies the above requirements is
The object of the present invention can be achieved by using a knitted fabric of fibers having the following properties.

First, the three basic characteristics of the 25-machi actuator of the present invention are that the intermediate layer is composed of a knitted fabric of fibers.

As is well known, fiber structures can be roughly divided into woven and knitted fabrics, but while the former hardly elongates, the latter can elongate to a very large extent depending on the structure and its constituent elements6.Therefore, knitted fabrics are used as the intermediate layer. is suitable. However, in order to comply with the gist of the present invention, the knitted fabric must have a tensile elongation at break of 55% or more, preferably 0% or more, and more preferably 90% or more. .

In addition, in order for the intermediate layer of the pneumatic actuator of the present invention to be able to deform in accordance with the one-pass expansion and contraction movement of the inner cylinder made of rubber or rubber-like elastic material, it is important that the elastic modulus of the knitted fiber material is not too high. , and the tensile force per unit width of the knitted fabric at 50% elongation is 1~fiX, 10"・(9
7 cm), more preferably 2=w x 1o8 (g/a
m)・, more preferably 4 to IX”'108 (')/
(-m''). In the case of knitted fabrics, the tensile force per unit width is generally used rather than the tensile force (stress) per unit area.

The five fibers that are the raw material for the knitted fabric constituting such an intermediate layer may be natural fibers or chemical fibers as long as they themselves have excellent durability. For example, natural fibers include plant fibers such as cotton and hemp, animal fibers such as silk and wool, and chemical fibers include nylon, polyester, acrylic,
Synthetic fibers such as vinylon, vinyl 1 resin, polypropylene, polyethylene, polyvinyl chloride, polyurethane, polyvinylidene blue, polyfluoroethylene, recycled fibers such as rayon, benbelv, polynosic, cupra, acetate, triacetate, promic 15s ,
Semi-synthetic fibers such as chlorinated rubber are suitable.

On the other hand, regarding the rubber or rubber-like elastic body constituting the inner cylinder and the braided structure covering its outer periphery, the previously-filed patents mentioned above [Japanese Patent Application No. 58-71,404, Japanese Patent Application No. 58-1]
60,544), but 2'.

First of all, the term "rubber or rubber-like elastic body" that constitutes the inner cylinder refers to rubber elastic bodies in general, such as natural rubber (NR
) and styrene-butadiene rubber (SBR),
Butadiene rubber (BR), I-Sobren rubber (KR),
Chloroprene rubber (OR), acrylonitrile butadiene rubber (NBR), isobutylene isoprene rubber (II
R), ethylene propylene rubber (EPR), ethylene propylene terpolymer (EPDM), silicone rubber,
Composite materials such as fluorocarbon rubber, urethane rubber, acrylic rubber, ethylene vinyl acetate copolymer (EVA), chlorinated polyethylene, chlorosulfonated polyethylene, fibers such as rectangular fibers and long fibers, various plasticizers, etc. Refers to general vulcanized rubber filled with Furthermore, it includes general plastics that exhibit rubber elasticity even though they are unvulcanized, such as various thermoplastic elastomers represented by SBS.

On the other hand, the braided structure can be made of not only the natural fibers and chemical fibers used in the intermediate layer 1 mentioned above, but also organic or inorganic high tensile strength fibers such as aromatic polyamide fibers, glass fibers, and carbon fibers, as well as twisted filaments such as ultrafine metal wires. Untwisted bundles are suitable.

As described above, in the pneumatic actuator of the present invention, by using the intermediate layer, the inner cylinder made of rubber or rubber-like elastic body is protected from the external braided structure, so the expansion/contraction bending life of the inner cylinder is significantly extended. 10, and as a result, the life of the actuator is dramatically improved. FIG. 2 shows a configuration diagram of the pneumatic actuator of the present invention. In the figure, 1 is an inner cylinder made of rubber or a rubber-like elastic body, 2 is a braided structure covering the outer periphery, and 14 is an intermediate layer 1 made of a knitted fabric of fibers.
It is 5.

[Example 1, Comparative Example 1] Regarding the following two types of pneumatic actuators,
Table 1 compares the number of 2" repetitions (life) until breakage when a bending test was conducted under conditions where the axial length was contracted by 25%.b In this case, Comparative Example 1 was As described above, it is a two-layer structure consisting of a rubber inner cylinder and a braided structure covering its outer periphery.On the other hand, in Example 1, between the rubber inner cylinder and the braided structure covering its outer periphery according to the present invention, It is a three-layer structure incorporating an intermediate layer consisting of a knitted fabric of fibers.In both comparative examples and examples, the rubber inner tube is made of NR insulating rubber vulcanizate, and the outer braided structure is made of nylon monofilament. On the other hand, the intermediate layer used in Example 1, which is a structure, has an Ill tensile force per unit width at 50% elongation of 6.
It is a knitted nylon fabric with a tensile elongation of 0 g/cm1 and 290%.

(Table 1) The results in Table 1 show that the pneumatic actuator of the present invention incorporating the intermediate layer has a significantly longer life than conventional products. As described above, the pneumatic actuator of the present invention has an intermediate layer made of a knitted fabric of fibers between an inner cylinder made of rubber or a rubber-like elastic body and a braided structure covering the outer periphery of this inner cylinder. By establishing
The 5-bend life of the pneumatic actuator before breakage has been greatly improved, and since it can be manufactured at low cost, it can greatly contribute to industrial development.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main parts of a conventional air-bag type pneumatic actuator, and FIG. 2 is an explanatory diagram of the main parts of the pneumatic actuator of the present invention. l... Tubular body 2... Braided structure 8... Closing member 4... Caulking cap 155.
... Nipple 6 ... Flange 7 ... Clevis end 8 ... Annular protrusion 9 ... Hole l
O... Internal cavity 11... Connection hole 12... Fitting 18...
Flare 14...middle class. ! 0 (11) Procedural amendment February 8, 1982 1, Indication of case 1982 Patent Application No. 245234 2, Title of invention Pneumatic actuator 3, Person making the amendment Relationship to the case Patent applicant (527) ) Brideston Tire Co., Ltd. 5゜6, "Detailed Description of the Invention" column 7 of the specification subject to amendment,
Contents of the amendment (as attached) (1) Changed “rectangular fiber” from page 8, line 16 of the specification to “short fiber”
Correct. (2) Change "l'-NR insulating rubber" to "N" on page 10, line 7.
Corrected to "R pure rubber". (2)

Claims (1)

[Scope of Claims] 1. In a two-mnematic actuator having an inner cylinder made of rubber or a rubber-like elastic body and a braided structure covering the outer periphery of the inner cylinder, there is a gap between the inner cylinder and the braided structure. , the tensile force per unit width at 50% elongation is 1 to Is
A pneumatic actuator 1'' characterized in that a knitted fabric of fibers of X I 08 (9/Cr-) is provided as an intermediate layer. 2. The pneumatic actuator according to claim 1, wherein the intermediate layer made of a knitted fabric of jL1a fibers has a tensile elongation at break of 55% or more.