JP7795449B2 - Processing method of elastic check valve and elastic check valve - Google Patents

Description

The present invention relates to a method for manufacturing an elastic check valve, which has a cylindrical check valve body and a valve element with a slit that is provided in a passage of the check valve body and allows fluid to pass in one direction through the slit but not in the reverse direction, and also relates to an elastic check valve.

Conventionally, airtight containers that contain an item inside in a sealed state have been known. For example, an intake valve and an exhaust valve are provided on the bottom of this airtight container, and an inert gas or the like is supplied into the container through the intake valve and exhausted through the exhaust valve as needed, thereby replacing the gas inside the container and maintaining an airtight state.

One such type of check valve is the elastic check valve described above, which has a cylindrical check valve body and a valve element with a slit located in the passage of the check valve body, which allows fluid to pass through the slit in one direction but not in the reverse direction. This valve element is made of soft rubber, and the slit is cut out manually using a special punching tool.

For example, as disclosed in Patent Document 1, a method is known in which melt-extruded resin is placed on the surface of a rotating cooling roll and cooled by blowing air onto it from an air knife device.

Also known is a method, as described in Patent Document 2, in which cooling air is blown from an air knife nozzle onto the surface layer of uncured thermoplastic resin to forcibly cool it, and then a foam layer is laminated onto the base layer.

JP 2012-6271 A Patent No. 3357182

However, conventional manual work using dedicated tools requires a number of steps: preparing a dedicated punching tool, setting the elastomer check valve into the tool, punching it out, and then removing the punched elastomer check valve from the tool. Furthermore, because cutting with a blade is done manually, there are safety concerns and it is extremely time-consuming.

The methods described in Patent Documents 1 and 2 above use an air knife, which can hold down the object being blown with air, but is not intended for cutting, such as slitting.

The present invention was made in light of these issues, and its purpose is to provide a safe and easy way to reliably provide a slit in the valve element of an elastic check valve.

To achieve the above objective, this invention uses air pressure to break a weakened portion that is pre-installed in the rubber valve body.

Specifically, in the first invention,
A cylindrical check valve body;
A method for manufacturing an elastic check valve having a valve body with a slit, the valve body having a slit and being integral with a passage of the check valve body, the valve body allowing fluid to pass through the slit in one direction but not in the reverse direction, comprising the steps of:
The slit is formed by circulating air in the one direction so that a weakened portion formed in advance on the valve body breaks, thereby breaking the weakened portion.

With the above configuration, when molding the elastic check valve, a weak section that is more likely to break than other sections is formed in the valve body in advance. Simply by passing air at an appropriate pressure in the direction that allows the fluid to pass through, the weak section breaks, safely and reliably forming a slit.

In a second aspect of the present invention, in the first aspect of the present invention,
the fragile portion is a portion that is thinner than other portions of the valve body,
The thickness of the weakened portion is 0.02 mm or more and 0.06 mm or less.

Here, making the fragile portion thinner than 0.02 mm is difficult to mold, and making it thicker than 0.06 mm makes it difficult to break with air. However, with the above configuration, the fragile portion has an appropriate thickness, making it easy to mold and reliably breaks with the pressure of ordinary compressed air, making it easy to manufacture an elastomer check valve.

In a third aspect of the present invention, in the first or second aspect of the present invention,
The valve body is made of rubber,
The hardness of the rubber is 20 or more and 90 or less in terms of durometer type A of JIS K6253.

Here, if the valve disc's Shore A hardness is lower than 20, it is too soft, and if it is higher than 90, it is too hard and does not function properly as a check valve. However, with the above configuration, the hardness is appropriate, so an elastic check valve is obtained that breaks easily and can properly function as a check valve after breaking.

In a fourth aspect of the present invention, in any one of the first to third aspects of the present invention,
The configuration is such that a discharge portion that discharges compressed air from a compressor is pressed against one end side of the check valve body, and the compressed air is sent in to break the fragile portion.

The above configuration makes it possible to form slits extremely easily and safely.

In a fifth aspect of the present invention, in the fourth aspect of the present invention,
The air pressure that breaks the fragile portion is set to 0.1 MPa or more and 2.0 MPa or less.

The above configuration allows the use of pressure from a typical compressor installed in a factory, etc., without the need for unnecessary pressurization equipment, and there is no risk of the valve body breaking at a location other than the slit due to excessive pressure.

In the sixth invention,
A cylindrical check valve body;
an elastic check valve having a valve body having a slit and integrally provided in a passage of the check valve body, the valve body allowing fluid to pass in one direction through the slit but not in the reverse direction,
The valve body is configured such that the gap between the valve body and the slit becomes gradually narrower as the valve body approaches the slit in the one direction, and a fractured surface is formed at the narrowest portion of the slit.

With the above configuration, a weak section that is more easily broken than other sections is formed in advance as a gradually narrowing section in the part of the valve body that will become the slit. For example, simply by passing air at an appropriate pressure in the direction that the fluid is to pass through, this weak section can be broken, safely and reliably forming the slit. This results in an elastic check valve that is inexpensive and easy to manufacture.

In a seventh aspect of the present invention, in the sixth aspect of the present invention,
It is made of a single piece of rubber molding.
The hardness of the rubber is 20 or more and 90 or less in terms of durometer type A of JIS K6253.

Here, if the valve disc's Shore A hardness is lower than 20, it is too soft, and if it is higher than 90, it is too hard and does not function properly as a check valve. However, with the above configuration, the hardness is appropriate, so an elastic check valve is obtained that is easily broken by air pressure and can properly function as a check valve after breaking.

As explained above, according to the present invention, a weak portion pre-installed in the valve body is ruptured by air, making it possible to reliably provide a slit in the valve body of an elastic check valve in a safe and easy manner.

FIG. 2 is a plan view showing a rubber check valve. FIG. 1B is a cross-sectional view taken along line IB-IB of FIG. 1A. 1C is an enlarged cross-sectional view of part II in FIG. 1B. FIG. 3 is a cross-sectional view corresponding to FIG. 2 according to a first modified example of the embodiment of the present invention. FIG. 10 is a cross-sectional view corresponding to FIG. 2 according to a second modified example of the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.

- Rubber check valve configuration -
1A and 1B show a rubber check valve 1 as an elastomer check valve according to an embodiment of the present invention. For example, this rubber check valve 1 is a check valve provided at the bottom of a sealed container (not shown) or the like to allow communication with the outside. The rubber check valve 1 as an elastomer check valve is made of, for example, a one-piece molded product of fluororubber, but is not particularly limited as long as it is an elastomer, and may be made of thermoplastic or thermosetting elastomer, or rubber such as silicone rubber or ethylene propylene rubber. Furthermore, it may be made partially of metal.

The rubber check valve 1 according to this embodiment has a cylindrical check valve body 2 and a valve element 3 integrally formed at the center thereof.

The check valve body 2 has an outer diameter suitable for insertion into a through-hole in a sealed container, but its shape is not particularly limited and may be cylindrical with a through-hole in the center, with an elliptical cross-section, a field track shape with a pair of straight sections, or a rectangular shape. As mentioned above, part of the check valve body 2 may be made of metal or plastic.

As shown in Figure 1B, the valve element 3 is molded integrally with the inner periphery of the check valve body 2, which forms the passageway. The spacing gradually narrows toward the tip, and the valve element 3 has a slit 4 that is linear in plan view at the center of the tip. This slit 4 is configured to allow fluid to pass in one direction (the direction of the arrow shown in Figure 1B) (slit 4 opens) and not pass fluid in the opposite direction (slit 4 closes), thereby functioning as a check valve.

As shown enlarged in Figure 2, the slit 4 is formed by a method described below in a weakened portion 5 formed in the center of a straight, flat band-shaped portion 6 at the tip of the valve body 3 in a plan view. The weakened portion 5 is thinner than other portions of the valve body 3 (e.g., t1 = approximately 0.5 mm), and the thickness t2 of the portion of the weakened portion 5 that becomes the slit 4 is 0.02 mm or more and 0.06 mm or less (0.02 ≦ t2 ≦ 0.06). The width W of the weakened portion 5 is, for example, 0.1 mm (W = 0.1). In the transverse cross-sectional view of the band-shaped portion 6 in Figure 2, the inclination angle α of the side surface of the groove that forms the weakened portion 5 is, for example, 67° (α = 67°).

Furthermore, the rubber hardness of the valve body 3 of the rubber check valve 1 after molding is 20 or more and 90 or less in durometer type A (Shore A) of JIS K6253.

- Processing method for rubber check valves -
Next, a method for manufacturing the rubber check valve 1 according to this embodiment will be described.

Although detailed explanations are omitted, the rubber check valve 1 is molded, for example, from fluororubber using a dedicated mold by injection molding or compression molding. During this molding step, as described above, a linear fragile portion 5 is formed in the band-shaped portion 6 at the tip of the valve body 3. Note that, for example, the check valve main body 2 and the valve body 3 may be molded in two colors using different rubber materials.

As shown in Figure 1B, the discharge part 10 (tip of the air gun), which discharges compressed air from the compressor, is pressed against one end (lower end) of the check valve body 2, and compressed air is sent in, allowing the air to flow in one direction that allows fluid to flow so that the weakened part 5 previously formed in the valve body 3 breaks, breaking the weakened part 5 and forming the slit 4. This eliminates the need for a special punching tool. Note that if air is sent in the opposite direction, the valve body 3 will deform and not break properly. Furthermore, the discharged fluid is not limited to air; other gases can also be used. The slit 4 is formed as if it had been torn by air pressure, and a fractured surface can be seen when viewed under magnification. The fractured surface closes when the valve body 3 closes, but air does not leak from the closed part.

At this time, the air pressure required to rupture the fragile portion 5 is set to between 0.1 MPa and 2.0 MPa. This allows the pressure of a typical compressor installed in factories, etc., to be used, eliminating the need for more pressurizing equipment than necessary. Furthermore, by setting the upper limit at 2.0 MPa or less, there is no risk of the pressure being too high and rupturing the valve body 3 in areas other than the slit 4.

In this way, when molding the rubber check valve 1, a fragile portion 5 that is more prone to breaking than other portions is formed in the valve body 3 in advance. Simply by passing air at an appropriate pressure in one direction to allow the fluid to pass through, the fragile portion 5 breaks, safely and reliably forming the slit 4.

The thickness of the fragile portion 5 is set to 0.02 mm or more and 0.06 mm or less because it is difficult to mold the fragile portion 5 thinner than 0.02 mm, and difficult to break with air if it is thicker than 0.06 mm. By giving the fragile portion 5 of this embodiment this appropriate thickness, it is easy to mold and reliably breaks with the pressure of ordinary compressed air, making it easy to manufacture the rubber check valve 1.

The rubber hardness of the valve disc 3 is set to 20 or more and 90 or less on the Shore A hardness scale because a hardness below 20 would be too soft, and a hardness above 90 would be too hard and would not function properly as a check valve. Because the valve disc 3 of this embodiment has the appropriate hardness, it breaks easily, resulting in a rubber check valve 1 that can properly function as a check valve after breaking.

As explained above, according to the present invention, the weakened portion 5 provided in advance on the valve body 3 is ruptured by air, so the slit 4 can be reliably provided in the valve body 3 of the rubber check valve 1 in a safe and easy manner.

--Modification 1--
3 shows a first modification of the embodiment of the present invention, which differs from the above embodiment in that the configuration of the fragile portion 5' is different. In the following first and second modifications, the same parts as those in FIGS. 1A to 2 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

In this modified example, in the cross-sectional view of the band-shaped portion 6, the width of the groove-shaped portion of the fragile portion 5' gradually narrows from the bottom, and remains constant at the top with a band-shaped thin plate formed at the top.

In this modified example, the thickness t2 of the fragile portion 5 is 0.02 mm or more and 0.06 mm or less (0.02≦t2≦0.06). The width W of the fragile portion 5 is also, for example, 0.1 mm (W=0.1). In the cross-sectional view of the band-shaped portion 6, the inclination angle α' of the side surface of the groove forming the fragile portion 5 is α'=90° in this modified example.

Note that this α' is, for example, between 45° and 90° (45°≦α'≦90°). α' = 67° corresponds to the above embodiment.

In this case, too, the fragile portion 5' can be broken by forcibly sending air in the direction that allows the fluid through the check valve, thereby forming the slit 4.

--Variation 2--
FIG. 4 shows a second modification of the embodiment of the present invention, which differs from the above-described embodiment and the first modification in that the configuration of the fragile portion 5 ″ is different.

In this modified example, a groove is also formed on the upper side of the fragile portion 5'', and in the cross-sectional view of the upper and lower band-shaped portions 6, the width of the groove-shaped portion is constant, and the fragile portion 5'' is made of a thin band-shaped plate. In other words, the fragile portion 5'' does not have to be at the top of the valve body 3, but may be located in the middle of the band-shaped portion 6 in the thickness direction.

In this modification, the thickness t2 of the fragile portion 5 is also 0.02 mm or more and 0.06 mm or less (0.02≦t2≦0.06). The width W of the fragile portion 5 is also, for example, 0.1 mm (W= 0.1 ). In the cross-sectional view of the band-shaped portion 6, the inclination angle α'' of the side surface of the groove portion forming the fragile portion 5 is α=90° in this modification. This α should be 45° or more and 90° or less (45°≦α''≦90°).

In this case, too, the fragile portion 5' can be broken by forcibly sending air in the direction that allows the fluid through the check valve, thereby forming the slit 4.

(Other embodiments)
The present invention may be configured as follows in relation to the above embodiment.

In other words, while in the above embodiment the weakened portion is linear in plan view, it may also be cross-shaped or V-shaped, for example. On the other hand, if the weakened portion is perforated, air may leak from the interlocking portion when the slit closes after breaking, which is undesirable.

In the above embodiment, a rubber check valve 1 is used in a sealed container, but this is not limited to this and it may also be used in piping, etc.

Note that the above embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses.

1. Rubber check valve (elastic check valve)
2. Check valve body
3 Valve body
4. Slit
5, 5', 5'' Weakened parts
6. Belt
10 Discharge part

Claims (7)

A cylindrical check valve body;
a valve body that is integrally formed on the inner periphery of the check valve body, the slits being linear in plan view at the tip and gradually narrowing toward the tip, and that allows fluid to pass through the slits in one direction but not in the reverse direction;
A method for processing an elastomer check valve, characterized in that a weak portion of a straight thin band-shaped plate, which is pre-formed at the tip of the valve body along the longitudinal direction of the flat band-shaped portion in the width center of the band-shaped portion, is broken by circulating air in one direction so that the weak portion breaks, thereby forming the slit. the fragile portion is made of a thin band-like plate portion that is thinner than the flat band-like portion,
2. The method for processing an elastic check valve according to claim 1, wherein the thickness of the thin band-shaped plate portion of the fragile portion is 0.02 mm or more and 0.06 mm or less. The valve body is made of rubber,
3. The method for processing an elastic check valve according to claim 1, wherein the hardness of the rubber is 20 or more and 90 or less in terms of durometer type A of JIS K6253. A method for processing an elastomer check valve as described in any one of claims 1 to 3, characterized in that an outlet portion that discharges compressed air of 0.1 MPa or more and 2.0 MPa or less is pressed against one end side of the check valve body, and the compressed air is sent in to break the fragile portion. 4. The method for processing an elastic check valve according to claim 1, wherein the weakened portion is formed in the thin band-shaped plate at a middle position in the thickness direction of the flat band-shaped portion. A cylindrical check valve body;
an elastic check valve having a valve body having a slit and integrally provided on the inner circumferential side of the check valve body which serves as a passage, the valve body allowing fluid to pass in one direction through the slit but not in the reverse direction,
The valve body has a gradually narrower gap as it approaches the slit in the one direction,
The slit is provided in a flat band-shaped portion that is straight in a plan view,
An elastic check valve characterized in that at the narrowest part of the slit, a fracture surface of a fragile portion that is thinner than the flat band portion is formed in the center of the width of the flat band portion along the longitudinal direction of the band portion . It is made of a single piece of rubber molding.
7. The elastic check valve according to claim 6, wherein the hardness of the rubber is 20 or more and 90 or less in terms of durometer type A of JIS K6253.