JP3869513B2 - Manufacturing method of composite bellows - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite bellows in which two or more kinds of materials are combined, and more particularly, to a composite bellows that operates at a very small pressure and can withstand a large pressure.
[0002]
[Prior art]
Conventionally, for example, a rubber molded body with a cloth such as a diaphragm is widely known as a working membrane part of a pneumatic device. This rubber molded body with cloth is a composite film of cloth (base cloth) and rubber. The cloth (base cloth) embedded in the rubber molded body has strength against operating pressure, and depending on the rubber material. The structure is airtight. Such a rubber molded body with cloth is attached while making a fold between the piston and the cylinder in the pneumatic device, and this rubber molded body with cloth is inserted into the cylinder from the piston wall when the piston is lowered by pressure. It works to move the folded part while rolling smoothly onto the wall without friction (so-called rolling action). On the contrary, when the pressure decreases and the piston rises, it works in the same way.
[0003]
However, in order to ensure a smooth rolling action without biting the cloth-containing rubber molded body, the ratio of the length to the outer diameter is limited to about 1: 1 at most even if a large ratio is taken. Therefore, it can be said that it is not suitable for pneumatic equipment that requires a large stroke in the longitudinal direction (relative to the outer diameter).
[0004]
In addition, as can be said for all conventional pneumatic devices, the working membrane portion that can withstand a large pressure cannot operate stably with a very small pressure. On the other hand, the working membrane part that operates at a very small pressure cannot withstand a large pressure in strength. In the graph showing the pressure-stroke relationship, it is preferable that the relationship is linear. In general, however, as the pressure increases, the followability of the stroke becomes worse and linearity cannot be obtained.
[0005]
[Problems to be solved by the invention]
The present invention was devised under such circumstances, and an object of the present invention is to provide a composite bellows that can operate at a very small pressure and can withstand a large pressure. It is another object of the present invention to provide a composite bellows that is excellent in stroke pressure responsiveness and can obtain a pressure-stroke linear relationship in a wide pressure range.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the method for producing a composite bellows of the present invention comprises preparing a cylindrical base material, arranging and fixing a plurality of filaments in the longitudinal direction of the surface of the cylindrical base material, Dipping treatment of the cylindrical base material to which the filamentous body is fixed in a rubber latex dispersion bath, connecting the adjacent filamentous bodies and forming the basic cylindrical body of the cylindrical body, and the longitudinal direction of the basic cylindrical body A step of compressing the basic cylinder from both ends toward the center, peeling the basic cylinder from the cylindrical base material, and forming a bellows shape on the basic cylinder.
[0010]
Further, as a preferred aspect of the present invention, the step of forming the bellows shape on the basic cylindrical body performs the bellows shape molding in a state where the rubber latex is not completely dried, and then the rubber latex is completely dried. Configured as follows.
[0011]
Further, as a preferred aspect of the present invention, the step of forming the bellows shape on the basic cylinder includes winding a ring member for forming the bellows-shaped bellows valley portion in the circumferential direction of the basic cylinder, and the longitudinal direction. It is configured to be performed after forming a plurality of pieces at a constant pitch.
[0012]
In the cylindrical body part according to the present invention, the filaments are arranged in a “stripe” shape only in the longitudinal direction, and the elastic body or the resin is connected between them, and the entire cylindrical body part has a bellows shape. Since it is formed, it can be operated with a very small pressure and can withstand a large pressure.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0014]
FIG. 1 is a sectional view showing a part of the composite bellows 1 of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG.
[0015]
As shown in FIG. 1, the composite bellows 1 includes a bellows-shaped cylindrical body portion 10 that expands and contracts in the longitudinal direction, that is, a cylindrical body portion 10 that alternately includes bellows valley portions 11 and bellows valley portions 15. . In the cylindrical body part 10, a plurality of thread bodies 20 are arranged side by side from end to end of the tubular body part 10 in the longitudinal direction, and the adjacent thread bodies 20 as shown in FIG. The tubular body 10 is hermetically connected by a stretchable rubber or resin that constitutes a substantially thick portion 30 of the tubular body 10.
[0016]
As shown in FIG. 2, the filaments 20 arranged in the longitudinal direction are preferably embedded so as to be arranged substantially evenly in the circumferential direction in the thick part 30 of the cylindrical body part 10.
[0017]
The filament 20 used in the present invention plays a role like a so-called “muscle” for increasing the strength of the cylindrical body portion 10. Specific materials include vinylon (yarn or fiber), polyester (yarn or yarn). Fiber), nylon (thread or fiber), rayon (thread or fiber), hemp (thread or fiber), cotton (thread or fiber), glass fiber, boron fiber, carbon fiber, aramid fiber, steel (metal), etc. It is done. Among them, particularly strong ones such as polyester fibers and nylon fibers are preferable. The thickness of the thread-like body 20 to be used may be appropriately determined in consideration of the outer diameter, the wall thickness, etc. of the cylindrical body portion 10, but generally a diameter of about Φ0.005 to Φ5 mm is preferably used.
[0018]
Such a thread-like body 20 is airtightly connected by the stretchable rubber or resin constituting the substantial thick portion 30 as described above. The thick part 30 is required to be stretchable mainly when the bellows-shaped bellows mountain part 15 is formed as shown in FIG. 2, and the circumferential direction indicated by an arrow (A) is required. Because it becomes. Examples of the rubber constituting the thick portion 30 having stretchability include polyisoprene, butadiene styrene rubber, acrylonitrile rubber, butyl rubber, neoprene, polysulfide rubber, polybutadiene, and natural rubber. In particular, as can be seen from the preferred production method described later, it is preferable to use natural rubber latex which is an emulsion obtained from rubber tree, or synthetic rubber latex produced by emulsion polymerization. As resin which comprises the thickness part 30 provided with a stretching property, resin elastomers, such as low density polyethylene and a soft vinyl chloride, are mentioned, for example. The thickness of the thick portion 30 is appropriately set according to the stretchable material to be used, the thickness (diameter) of the filament 20 embedded in the thick portion 30, etc. It is preferable to set in the range of 005 to 10 mm.
[0019]
Furthermore, it is preferable that the ring member 7 for forming the bellows valley portion 11 of the cylindrical body part 10 is wound around the cylindrical body part 10 in the circumferential direction. It is preferable that a plurality of ring members 7 are provided on the surface of the cylindrical body portion 10 at a constant pitch corresponding to the position of each bellows valley portion 11. Further, the ring member 7 is preferably fixed to the cylindrical body portion 10. By using such a ring member 7, the pitch of the bellows shape can be set arbitrarily and accurately. For example, if the pitch is reduced to reduce the undulation of the bellows valley portion 11 and the bellows mountain portion 15, the pressure-stroke can be reduced. In the graph which shows a relationship, the favorable pressure responsiveness that both relationship shows linearity in a wide pressure range is shown. Furthermore, the ring member 7 contributes to the improvement of the bellows shape.
[0020]
Such a ring member 7 can be used without any particular limitation as long as it is a material that can regulate the diameter of the bellows valley portion 11 and has almost no stretchability (form is linear), and can be used as a metallic material or plastic material. Any of these may be used.
[0021]
The cylindrical body portion 10 of the present invention described above can have a large ratio of the length to the outer diameter, and can take a very large stroke in the longitudinal direction. Further, by adopting the filaments 20 arranged in a stripe shape in the longitudinal direction and the stretchable thick part 30 structure formed so as to wrap the filaments, the filaments 20 can be operated with a very small pressure and can be applied to a large pressure. It is possible to realize a composite bellows that can withstand.
[0022]
Next, the suitable manufacturing method of the composite bellows 1 of this invention is demonstrated based on FIG. 3 and FIG.
[0023]
First, as shown in FIG. 3A, a cylindrical substrate 50 is prepared for arranging and setting filaments in the longitudinal direction.
[0024]
Next, a plurality of filaments 20 are set on the cylindrical base material 50 one by one in the longitudinal direction (from one end 50a to the other end 50b of the cylindrical base material 50), and substantially in the circumferential direction. The filament 20 is set over the entire area (FIG. 3B).
[0025]
Next, the cylindrical base material 50 to which the thread-like body 20 is fixed is dipped in a rubber latex dispersion bath from one end in the longitudinal direction of the cylindrical base material 50 to connect the adjacent thread-like bodies 20 to each other and expand and contract. The thick wall portion 30 is formed to form the basic cylindrical body 10 ′ of the cylindrical body portion 10 (FIG. 3C). Due to the dipping process, rubber latex enters the gap between the filament 20 and the filament 20 and the gap between the filament 20 and the surface of the cylindrical base material 50 by capillary action. Then, it is embedded in the thick part 30 of the basic cylinder 10 ′ (see FIG. 2).
[0026]
Next, the ring member 7 for forming the bellows-shaped bellows valley portion is wound at a constant pitch P in the circumferential direction of the basic cylinder 10 ′ ((d) in FIG. 4). It is preferable to adhere to the surface of the basic cylinder 10 ′.
[0027]
Next, while compressing the base cylinder 10 'from both ends in the longitudinal direction of the base cylinder 10' toward the center, the base cylinder 10 'is peeled from the cylindrical base material 50, and the base cylinder 10' A bellows shape is formed ((e) in FIG. 4).
[0028]
Next, the base cylindrical body 10 ′ formed with the bellows shape is separated from the cylindrical base material 50 to obtain the composite bellows 1 of the present invention as shown in FIG. 4 (f).
[0029]
In the step of forming the bellows shape on the basic cylindrical body 10 ', it is preferable to mold the bellows shape in a state where the drying of the rubber latex is incomplete, and then to completely dry the rubber latex. . This is to prevent the bellows-shaped mold from slipping and to stabilize the bellows shape for a long period of time.
[0030]
The composite bellows 1 of the present invention is particularly preferably manufactured by the above-mentioned dipping method from the viewpoints of manufacturing simplicity, product quality stability, and the like. It can also be manufactured by a method.
[0031]
The composite bellows 1 of the present invention can be used as, for example, a pump or an actuator that absorbs a change in volume of liquid due to a temperature change, in addition to a pneumatic device.
[0032]
【The invention's effect】
The composite bellows of the present invention is a bellows provided with a cylindrical body part that expands and contracts in the longitudinal direction, and the cylindrical body part has a plurality of thread bodies arranged in the longitudinal direction, and adjacent thread bodies are arranged between each other. Since it is configured to be connected by stretchable rubber or resin, it can be operated with a very small pressure and can withstand a large pressure. It also has excellent stroke pressure response.
[0033]
Furthermore, the composite bellows of the present invention produces particularly excellent effects such as ease of production and stability of product quality by producing by the so-called dipping method.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a part of a composite bellows of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is a schematic view for explaining a preferred method for producing the composite bellows of the present invention over time.
FIG. 4 is a schematic view for explaining a preferable method for producing the composite bellows of the present invention over time.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Composite bellows 7 ... Ring member 10 ... Cylindrical body part 11 ... Bellows valley part 15 ... Bellows mountain part 20 ... Filamentous body 30 ... Thick part

Claims (3)

Preparing a cylindrical base material, and arranging and fixing a plurality of filaments in the longitudinal direction of the surface of the cylindrical base material; and
A step of dipping the cylindrical base material to which the filamentous body is fixed in a rubber latex dispersion bath, connecting the adjacent filamentous bodies together, and forming a basic tubular body of the tubular body part;
A step of forming the bellows shape on the basic cylinder while peeling the basic cylinder from the cylindrical base material while compressing the basic cylinder toward the center from both longitudinal ends of the basic cylinder. A method for producing a composite bellows characterized by the following. Step of forming a bellows shape on the basis tubular body, drying the rubber latex performs typing bellows with an incomplete, thereafter, the production of the composite bellows according to claim 1 for complete drying of rubber latex Method.   The step of forming the bellows shape on the basic cylindrical body is performed after winding a ring member for forming the bellows-shaped bellows valley portion in the circumferential direction of the basic cylindrical body and forming a plurality at a constant pitch in the longitudinal direction. The method for producing a composite bellows according to claim 1.

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