JP4250956B2 - Seal structure - Google Patents

Description

【００８４】
なお、表１の燃料浸漬後の接着強度試験の欄の実施例４の＊印の注記として、「但し、内側ゴムと外側ゴムの接合部分の界面の接着性が若干弱い。」とあるのは、上記した燃料浸漬後の接着強度試験において、接着強度は概ね良好であったが、接合部分の界面の一部にわずかな剥がれがあるのが観察されたため、接着性が加硫接着に比べて弱いという意味で、接着性が弱いとしたものである。ただし、燃料透過性能およびシール性能に影響を与える程度でないことは、上表１の燃料透過性試験およびシール試験結果が示す通り良好であることから明白である。なお、他の実施例で行った加硫接着による接合の場合には、当該接合部分に剥がれなどの異常は認められず、接着性は良好であった。
【００８５】
実施例１では、材料が同じＮＢＲ同士で比較した場合、すなわち比較例１と比較した場合に燃料透過性試験での燃料透過量（ｍｇ／個／ｄａｙ）が５０％改善されており、ＮＢＲ材料において、燃料バリア性と低温シール性を長期間確実に維持することができるＮＢＲ製のシール構造体を提供することができることが確認された。
【００８６】
実施例２〜５では、材料が同じフッ素ゴム同士の比較例２、３と対比した場合、比較例２よりも燃料透過性は極わずか低下しているものの、同時にシール性（特に低温シール性）にも優れていることが明確になっており、シール性のよい比較例３よりも燃料透過性は３０〜４０％も改善されているため、本発明の目的である、燃料バリア性と低温シール性を長期間確実に維持することができるフッ素ゴム製のシール構造体を提供することができることが確認された。
【００８７】
なお、本発明は、その精神または主要な特徴から逸脱することなく、他のいろいろな形で実施することができる。それゆえ、前述の実施例はあらゆる点で単なる例示にすぎず、限定的な解釈してはならない。本発明の範囲は、特許請求の範囲によって示すものであって、明細書本文には、なんら拘束されない。さらに、特許請求の範囲の均等範囲に属する変形や変更は、すべて本発明の範囲内のものである。
【図面の簡単な説明】
【図１】 シール構造体適用の一例図である。
【図２】 本発明に係る２種類のゴムを並設（並列に設置）させた構造を有するシール構造体（丸断面）の断面図である。
【図３】 本発明に係る３種類のゴムを並設させた構造を有するシール構造体（丸断面）の断面図である。
【図４】 本発明に係る３種類のゴムを並設させた構造を有するシール構造体（丸断面）の断面図である。
【図５】 本発明に係る２種類のゴムを並設させた構造を有するシール構造体（Ｈ断面）の断面図である。
【図６】 本発明に係る２種類のゴムを並設させた構造を有するシール構造体（変形Ｈ断面）の断面図である。
【図７】 本発明に係る３種類のゴムを並設させた構造を有するシール構造体（Ｈ断面）の断面図である。
【図８】 本発明に係る３種類のゴムを並設させた構造を有するシール構造体（変形Ｈ断面）の断面図である。
【図９】 本発明に係る２種類のゴムを並設させた構造を有し、かつ他の２種類のゴムを直設（直列に設置）させた構造を有するシール構造体（丸断面）の断面図である。
【図１０】 本発明に係る３種類のゴムを並設させた構造を有し、かつ中間層のゴム内に他のゴムを、いわば海島構造となるように設置させた構造を有するシール構造体（丸断面）の断面図である。
【図１１】 図１１（Ａ）および（Ｂ）は、共に本発明に係る３種類のゴムを並設させた構造を有するシール構造体（丸断面）の断面図であって、該３種類のゴムの並設構造の範囲を例示した解説図面である。
【符号の説明】
１…シール構造体、
１ａ…シール構造体を構成するゴム材料、
１ｂ…シール構造体を構成するゴム材料、
１ｃ…シール構造体を構成するゴム材料、
２…管状体、
３…管状体、
４…カシメ部品、
５ａ、５ｂ、６ａ、７ａ、７ｂ、８ａ…内周のゴムの接点、
５ｃ、５ｄ、６ｂ、７ｃ、７ｄ、８ｂ…外周のゴムの接点、
６ｃ、８ｃ…シール構造体の断面形状の下面、
Ｌ…シール構造体の断面形状における内周から外周までの全幅。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber seal structure, and more particularly, to a seal structure having a high fluid tightness, particularly a fuel barrier property (fuel impermeability) formed by juxtaposing two or more types of rubber. Is.
[0002]
[Prior art]
A ring-shaped seal structure such as an O-ring is used for a joint portion in various fluid pipes so as not to leak an internal liquid phase fluid and / or a gas phase fluid to the outside. Normally, the material of this seal structure is selected according to the fluid flowing inside and the usage environment. For example, in a seal structure in a fuel pipe of an automobile or the like, acrylonitrile butadiene rubber (NBR) and polyvinyl chloride are used for NBR. Blended materials (NBR-PVC), fluorine rubber (FKM), fluorosilicone rubber (FVMQ) and the like are generally used.
[0003]
On the other hand, emissions of hydrocarbon substances (HC) such as automobile fuel that are transpiration into the atmosphere have been regulated in recent years, and the sealing performance of the joints in the fuel system of automobiles is higher than before. Is now required. For this reason, in parts where fuel impermeability (fuel barrier properties) is required, fluororubbers are used in the above rubbers, and in order to ensure excellent sealing properties particularly at low temperatures, A composition having excellent low-temperature flexibility, for example, a ternary fluororubber mainly composed of tetrafluoroethylene, vinylidene fluoride, and polymethylvinyl ether is used.
[0004]
However, those having high flexibility at low temperatures generally have poor fuel barrier properties at room temperature. For example, the above-described ternary fluororubbers with improved low-temperature flexibility are binary general fluororubbers and fluorides. Compared with ternary fluororubber composed of vinylidene, tetrafluoroethylene, and hexafluoropropylene, the fuel barrier property is lowered.
[0005]
For this reason, it has been proposed to achieve both low temperature sealing properties and fuel barrier properties by coating the surface of rubber with excellent low temperature flexibility with resin or other rubber. For example, NBR coated with a nylon resin, FVMQ or hydrin rubber coated with a fluororesin or nylon resin can be cited as a rubber coated resin (see, for example, Patent Documents 1 and 2). Moreover, what coated the rubber | gum which is excellent in the sealing performance in low temperature as what coated rubber | gum on the rubber surface (for example, refer patent document 3).
[0006]
However, when the former rubber surface is coated with resin, the fuel barrier property of the sealing structure itself is enhanced, but the coating resin undergoes low-temperature curing in a cold usage environment, ensuring adhesion to the mating parts. Cannot be performed and the sealing performance is insufficient.
[0007]
In addition, the latter rubber surface coated with another rubber can be secured at low temperature because there is no curing at low temperature, but it is extremely difficult to form a uniform film in the first place. For example, since an O-ring has a circular cross section, a liquid dripping portion is generated in a part, and a gap with a counterpart part is generated in the liquid dripping portion, which causes a problem that sealing performance cannot be secured in this portion.
[0008]
In addition, such a coating technique is also a major issue in ensuring adhesion. For example, in a distribution medium such as gasoline, the sealing material swells, so that it is extremely difficult to ensure adhesion that can sufficiently withstand use. .
[0009]
[Patent Document 1]
Japanese Patent Publication No. 4-27938
[Patent Document 2]
JP 2001-182837 A
[Patent Document 3]
JP 2001-150595 A
[0010]
[Problems to be solved by the invention]
Therefore, there is no conventional seal structure that ensures sufficient fuel barrier properties and low temperature seal properties. An object of the present invention is to provide a rubber seal structure that can reliably maintain fuel barrier properties and low-temperature seal properties for a long period of time.
[0011]
[Means for Solving the Problems]
The present invention for solving the above problems is a seal structure installed at a joint portion of a tubular body,
The seal structure is a structure in which at least two kinds of rubber are arranged in a concentric circle with respect to the fluid flow center,
The rubber on the inner peripheral side with respect to the fluid flow center has higher fluid tightness at room temperature than any of the rubbers positioned on the outer peripheral side,
The rubber positioned on the outer peripheral side with respect to the fluid flow center has higher fluid tightness in a temperature range of at least −30 ° C. to −50 ° C. than any of the rubber positioned on the inner peripheral side. This is a seal structure.
[0012]
Further, a more preferable configuration of the seal structure for solving the above problems (the invention according to claim 2) is the seal structure,
The seal structure has two or more contact points with a mating part for fluid-tight sealing when viewed in its cross-sectional shape,
The seal structure according to claim 1, wherein at least one rubber forms one or more contacts, and at least one different rubber forms one or more different contacts. .
[0013]
Furthermore, in a more preferable configuration of the seal structure for solving the above problems (the invention according to claim 3), in the seal structure, at least the rubber constituting the inner periphery is fluoro rubber. Alternatively, the seal structure according to 2 is provided.
[0014]
Furthermore, in a more preferable configuration of the seal structure for solving the above-described problem (the invention according to claim 4), in the seal structure, all the rubbers constituting the seal structure are fluororubbers. The seal structure according to the above.
[0015]
Furthermore, a more preferable configuration of the seal structure for solving the above-described problem (the invention according to claim 5) is that the rubber constituting the seal structure is juxtaposed before vulcanization and bonded at the time of vulcanization. The seal structure according to any one of claims 1 to 5.
[0016]
Furthermore, a more preferable configuration of the seal structure for solving the above problems (the invention according to claim 6) is that the outer peripheral rubber is fluororubber having a TR10 value ≦ −20 ° C. in the seal structure. The inner peripheral rubber is a fluororubber seal structure having a gasoline permeability coefficient at 40 ° C. of 1/2 or less of the outer peripheral rubber.
[0017]
Furthermore, a more preferable configuration of the seal structure for solving the above problems (invention according to claim 7) is the rubber constituting the seal structure, the inner peripheral side of which is tetrafluoroethylene, vinylidene fluoride, The seal structure is a fluororubber made of hexafluoropropylene, and the outer periphery thereof is a fluororubber made of tetrafluoroethylene, vinylidene fluoride, and perfluoromethyl vinyl ether.
[0018]
【The invention's effect】
Since the present invention is configured as described above, the fuel barrier property (fuel impermeability) and the sealing property are high both at normal temperature (use environment temperature) and at low temperatures, and between parallel rubbers even during long-term use. A seal structure with low peeling can be provided.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The seal structure of the present invention is a seal structure installed in a joint portion of a tubular body,
The seal structure is a structure in which at least two kinds of rubber are arranged in a concentric circle with respect to the fluid flow center,
The rubber on the inner peripheral side with respect to the fluid flow center has higher fluid tightness at room temperature than any of the rubbers positioned on the outer peripheral side,
The rubber positioned on the outer peripheral side with respect to the fluid flow center has higher fluid tightness in a temperature range of at least −30 ° C. to −50 ° C. than any of the rubber positioned on the inner peripheral side. It is what.
[0020]
The measurement and evaluation of fluid tightness can generally be performed as follows.
[0021]
A rubber material (for example, O-ring) is used under the following conditions. The level of fluid tightness can be evaluated by the value (leakage amount: mg / day) obtained by measurement.
[0022]
・ O-ring shape: Wire diameter 3.1mm, O-ring inner diameter 130mm
・ O-ring compression ratio: 15%
・ Fuel pressure: 0.5Mpa at 23 ° C or more, no load pressure at less than 23 ° C
・ Container volume: 40ml
Measurement item: Leakage after 504 hours (mg / day)
・ Measurement method;
(1) At 23 ° C. or higher: Measured by the SHED method. Specifically, an aluminum container (internal volume 40 ml) in which gasoline (test fluid) is sealed is sealed with a rubber material (both use the O-ring defined above), and at room temperature (23 ° C. or higher). The inside of the container was pressurized to 0.5 MPa below, and the amount of gasoline leaked through the O-ring (mg / day) after 504 hours (three weeks) from the start of pressurization was measured as a measuring device. Mini VT SHED (capacity 2m) ^Three ) Is combined with an analyzer MEXA7200 manufactured by Horiba, Ltd.
[0023]
(2) Below 23 ° C .: Measured by gravimetric method. Specifically, an aluminum container (internal volume 40 ml) in which gasoline (test fluid) is sealed is sealed with a rubber material (both using an O-ring as defined above), and at room temperature (below 23 ° C). ) From the start of pressurization under low temperature (-30 to -50 ° C.), the amount of gasoline leaking through the O-ring after 504 hours (3 weeks) (decreased amount of enclosed fuel; mg / day) Measure.
[0024]
-The leak amount of gasoline leaking out is the total amount of what leaks through the O-ring (rubber material) and leaks at the interface between the container and the O-ring.
[0025]
Therefore, the low fluid density in the present invention is a rubber material having high fluid tightness as the amount of leaked gasoline or the like leaked by the above measurement is small, and conversely obtained by the above measurement. It can be said that the larger the leakage amount of gasoline or the like that leaks, the lower the fluid tightness of the rubber material.
[0026]
In the present invention, measurement and evaluation of fluid tightness of the rubber (O-ring) is performed at room temperature and a temperature range of −30 ° C. to −50 ° C., and a combination of rubbers satisfying the above requirements of the present invention, That is, the parallel arrangement of two or more kinds of rubbers constituting the seal structure may be appropriately determined. In addition, as long as the leakage amount (fluid tightness) of rubber can be measured, the conditions shown in the above-mentioned measurement and evaluation methods for fluid tightness of rubber and the measuring device are not limited at all. Measurement devices can be set and evaluated appropriately. For example, when the test fluid is gasoline, it is generally pressurized to 0.5 MPa at 23 ° C. or more. However, the pressure is not particularly limited, and the pressurizing condition in the case of other fluid is the other fluid. It can be said that it may be performed under the same conditions as those generally used.
[0027]
Whether or not the seal structure has a structure in which at least two types of rubber are arranged concentrically with respect to the fluid flow center can usually be determined by looking at the cross section of the seal structure, and has almost the same composition. In this case, it can be easily discriminated when viewed with an optical microscope. Further, the components of two or more kinds of rubber constituting the seal structure can be easily analyzed by analyzing the cross section. If there is usually 2mm square, the material type and composition ratio can be analyzed.
[0028]
Hereinafter, the seal structure of the present invention will be described in detail with reference to the accompanying drawings.
[0029]
FIG. 1 is a schematic cross-sectional view schematically showing an example of a state in which the seal structure of the present invention is installed at a joint portion of a tubular body. As shown in FIG. 1, the seal structure 1 of the present invention is installed at a joint portion of a first tubular body 2 (for example, a pump module) and a second tubular body 3 (for example, a fuel tank). . Reference numeral 4 in the figure denotes a crimped part of the first tubular body 2 and the second tubular body 3 (for example, a screwing member such as a lock ring can be used). The in-tube fluid passes through the inside of the first tubular body 2 and the second tubular body 3, and the seal structure 1 is used for fluid-tightening between the first tubular body 2 and the second tubular body 3. is set up.
[0030]
FIG. 2 is a drawing showing a typical cross-sectional structure of the seal structure of the present invention. As shown in FIG. 2, the cross section of the seal structure has two types of rubber arranged in parallel to the center of the fluid flow (see FIG. 1). The rubber 1a on the side (inner side of the pipe; hereinafter, also simply referred to as the inner peripheral side or the inner circumference) is more than the rubber 1b on the outer peripheral side (outer side of the pipe; hereinafter, also referred to simply as the outer peripheral side or outer circumference). However, the rubber 1b on the outer peripheral side is a rubber having higher fluid tightness than the rubber 1a on the inner peripheral side at least in the temperature range of −30 ° C. to −50 ° C. ing. With this structure, excellent fluid tightness can be obtained in both ambient and low temperature environments.
[0031]
The reason why the inner peripheral rubber has fluid tightness at room temperature is as follows. A material having low fluid tightness is swollen by a fluid in the pipe (for example, gasoline), so that a large internal stress is generated inside the material. Due to the internal stress, the molecular chain of the rubber material is broken, and a load is applied to the rubber material, which promotes deterioration. For this reason, it is possible to reduce the degree of internal stress load and further improve the durability by installing a rubber material having higher fluid tightness in the normal temperature range where the frequency of use is high on the inner peripheral side. Moreover, by reducing this internal stress, it is possible to prevent peeling between the inner periphery and the outer periphery. From these two points, it was decided to install a highly fluid-tight rubber at normal temperature on the inner periphery side. Is.
[0032]
Here, the rubber satisfying the above requirements, specifically, a combination of rubber materials satisfying the above requirements used for the inner and outer rubbers when two kinds of rubber are juxtaposed as shown in FIG. Enumerate.
[0033]
(1) Hydrogenated NBR on the inner circumference side, NBR on the outer circumference side,
(2) NBR-PVC on the inner circumference side, NBR on the outer circumference side,
(3) Binary fluorine rubber (vinylidene fluoride / tetrafluoroethylene) on the inner peripheral side, ternary fluorine rubber (vinylidene fluoride / tetrafluoroethylene / perfluoromethyl vinyl ether) on the outer peripheral side,
(4) ternary fluororubber (vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene) on the inner circumference side, ternary fluororubber (vinylidene fluoride / tetrafluoroethylene / perfluoromethyl vinyl ether) on the outer circumference side,
(5) A combination of ternary fluororubber (vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene) on the inner peripheral side and FVMQ on the outer peripheral side corresponds to this. However, the rubber combination satisfying the above requirements of the present invention is not limited to these.
[0034]
The seal structure of the present invention may be a structure in which at least two kinds of rubbers are arranged in a concentric circle with respect to the fluid flow center, and may be a structure in which three or more kinds of rubbers are arranged in parallel. Good.
[0035]
For example, in the seal structure 1 in which two kinds of rubbers shown in FIG. 2 are arranged in parallel, a third rubber may be installed between the inner peripheral rubber 1a and the outer peripheral rubber 1b. Specifically, as shown in FIG. 3, as the third rubber 1c, an adhesive rubber or the like can be appropriately applied between the inner peripheral rubber 1a and the outer peripheral rubber 1b.
[0036]
Or as another aspect, you may install the 3rd rubber | gum 1c in the outermost periphery of the seal structure 1 like FIG. The third rubber 1c in FIG. 4 is effective when an inexpensive rubber is used to provide the seal structure economically.
[0037]
As an example of the combination shown in FIG. 3, a combination of ternary fluororubber (vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene) on the inner peripheral side, NBR as the intermediate layer, and FVMQ on the outer peripheral side corresponds to this. However, the combination of rubber materials satisfying the above requirements of the present invention is not limited to these. In the combined seal structure 1 of FIG. 3, the rubber 1a on the inner peripheral side with respect to the fluid flow center has higher fluid tightness at normal temperature than either the rubber 1c or 1b positioned on the outer peripheral side. Alternatively, it is sufficient that the rubber 1b on the inner peripheral side with respect to the fluid flow center has higher fluid tightness at normal temperature than the rubber 1c positioned on the outer peripheral side. On the other hand, the rubber 1b located on the outer peripheral side with respect to the fluid flow center has a higher fluid tightness in a temperature range of at least −30 ° C. to −50 ° C. than either the rubber 1c or 1a located on the inner peripheral side. The rubber 1c which has the property or is located on the outer peripheral side with respect to the fluid flow center has higher fluid tightness in the temperature range of at least −30 ° C. to −50 ° C. than the rubber 1a located on the inner peripheral side. What is necessary is just to have.
[0038]
As an example of the combination of FIG. 4, ternary fluororubber (vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene) on the inner peripheral side, binary fluororubber (vinylidene fluoride / tetrafluoroethylene) as the intermediate layer, outer periphery Various combinations such as NBR on the side are possible. Therefore, the combination of rubber materials satisfying the above requirements of the present invention is not limited to these. In the combined seal structure 1 of FIG. 4, the rubber 1a on the inner peripheral side with respect to the fluid flow center has higher fluid tightness at normal temperature than either the rubber 1b or 1c positioned on the outer peripheral side. Alternatively, it is sufficient that the rubber 1b on the inner peripheral side with respect to the fluid flow center has higher fluid tightness at normal temperature than the rubber 1c positioned on the outer peripheral side. On the other hand, the rubber 1c located on the outer peripheral side with respect to the fluid flow center has a higher fluid tightness in a temperature range of at least −30 ° C. to −50 ° C. than either the rubber 1a or 1b located on the inner peripheral side. The rubber 1b located on the outer peripheral side with respect to the fluid flow center has higher fluid tightness in the temperature range of at least −30 ° C. to −50 ° C. than the rubber 1a located on the inner peripheral side. What is necessary is just to have.
[0039]
These rubbers to be used should not be restricted as long as the above requirements are satisfied. For example, modifications that can be easily conceived by those skilled in the art such as improving the adhesiveness of the rubber materials exemplified above. A rubber material or the like that is appropriately woven may be used.
[0040]
Furthermore, as a preferable form of the sealing structure, when viewed in its cross-sectional shape, it has a mating part (two tubular body parts that need to be jointed) and two or more contacts for fluid-tight sealing. It is desirable that at least one rubber forms one or more contacts, and at least one different rubber forms one or more different contacts. In the case of a seal structure composed of two types of rubber, for example, one having the cross-sectional shape of FIG. The cross-sectional shape of the seal structure shown in FIG. 5 has contacts 5a, 5b, 5c, and 5d between mating parts (for example, in the case of FIG. 1, the first tubular body 2 and the second tubular body 3). Yes, this contact is made of different rubber. The shape shown in FIG. 5 is a four-contact shape, and the inner peripheral rubber 1a and the outer peripheral rubber 1b constitute two contacts 5a, 5b and 5c, 5d, respectively. By adopting a shape having such a contact, each rubber can surely come into contact with the counterpart part, and a more reliable sealing property can be obtained. The number of contacts is not particularly limited. If at least two points have contacts, the sealing performance is greatly improved as compared to a shape without contacts. As the two-point shape, FIG. 6 illustrates an example having contacts 6a and 6b with a counterpart part. In addition, the lower surface 6c of the seal structure 1 in FIG. 6 is in contact with one of the mating parts (in the case of FIG. 1, the second tubular body 3).
[0041]
In the embodiment of the seal structure shown in FIGS. 5 and 6, a third rubber may be set as shown in FIGS. 3 and 4. In other words, even a seal structure composed of three or more types of rubber has at least one contact point with a mating part for fluid tight sealing when viewed in cross-sectional shape. It is desirable to form one or more contacts, and at least one different rubber forms one or more different contacts. For example, as shown in FIG. 7, when the seal structure 1 has an H-shaped cross section, two contact points (contact points 7a, 7b of the inner peripheral rubber 1a) are respectively provided on the inner peripheral rubber 1a and the outer peripheral rubber 1b. And the contact point 7c, 7d) of the outer peripheral rubber 1b, and the intermediate layer rubber 1c may not be provided with a contact point. Further, as shown in FIG. 8, when the seal structure 1 has a modified H-shaped cross section, one contact point (one contact point 8a of the inner peripheral rubber member 1a) and the outer peripheral rubber member 1a and the outer peripheral rubber member 1b. It is only necessary to have the contact 7b) of the outer peripheral rubber 1b, and no contact may be provided on the rubber 1c of the intermediate layer. However, it is needless to say that contacts may be formed on the rubber 1c of the intermediate layer if necessary. Similarly, in the case of a seal structure composed of four or more types of rubber, different contact points may be formed in any two or more types of rubber from among the four or more types of rubber constituting the seal structure. Well, it can be said that not all types of rubber need be contacted. In addition, the cross-sectional shape may not be an H-shaped cross-sectional shape or a modified H-shaped cross-sectional shape as shown in FIGS.
[0042]
In addition, a contact here means that the part which contacts a counterpart component in the cross-sectional shape of a seal structure is a point contact. As shown in FIGS. 5 and 6, the size (width or length) of the point contact portion in the cross-sectional shape of the seal structure does not have to be strictly a point, and may have a slight width. The size of the width is included in the point contact in the present invention as long as it is up to about 30% of the entire width L from the inner periphery to the outer periphery in the cross-sectional shape of the seal structure 1. That is, it counts as a contact. Therefore, as shown in FIG. 6, in the cross-sectional shape of the seal structure 1, the surface 6 c that contacts one of the counterpart parts is not included in the contact point in the present invention.
[0043]
Furthermore, as an embodiment of this preferred seal structure, at least the rubber constituting the inner periphery is made of fluororubber. As described above, the inner circumferential rubber (the innermost circumferential rubber when three or more kinds of rubbers are arranged in parallel) is a rubber that bears fluid tightness at room temperature and a rubber that comes into contact with the fluid. Therefore, the inner peripheral rubber needs to have excellent fuel barrier properties and flexibility at room temperature, and chemical resistance. From this point, fluororubber is most suitable, and when fluororubber is applied, an excellent seal structure can be provided.
[0044]
More preferably, the rubber constituting the seal structure is entirely fluororubber. That is, it is desirable that two or more kinds of different fluororubbers are arranged in parallel. In this case, in addition to the advantage when the inner peripheral side is a fluororubber, the adhesive property is remarkably improved by arranging the fluororubbers side by side, and an excellent seal structure with little change over time such as peeling even in long-term use. It becomes possible to provide.
[0045]
The adhesion between the rubbers arranged side by side is preferably vulcanization adhesion. Specifically, two or more kinds of rubbers constituting the seal structure are arranged side by side before vulcanization, and are bonded together (between different types of rubbers arranged side by side) at the time of vulcanization. . That is, it is preferable to put rubber before vulcanization (a plurality of rubbers to be arranged side by side) into a desired mold such as transfer, and simultaneously bond them when vulcanized in the mold (implementation other than Example 4 described later). In this example, this bonding method was used, which is simply referred to as “in-mold vulcanization bonding method” in the examples.) When the rubbers arranged side by side are of the same type, the rubbers arranged side by side can be cross-linked and have excellent adhesiveness. Vulcanization can be appropriately selected according to the rubber used, such as sulfur and peroxide. However, the adhesion between the rubbers arranged side by side is not limited to vulcanization adhesion, and other conventionally known adhesion methods may be applied as long as sufficient adhesion strength can be obtained.
[0046]
Further, the rubber on the outer peripheral side is a fluororubber having a TR10 value = −20 ° C. or less, the rubber on the inner periphery is a fluororubber having a TR10 value = −20 ° C. or higher, and the gasoline permeability coefficient at 40 ° C. One half or less is desirable. When selecting rubber having such characteristics, it is suitable as a packing installed between the fuel tank for an automobile and the pump module (see FIG. 1). By installing fluoro rubber with TR10 value ≦ −20 ° C. on the outer periphery, it has excellent sealing properties even in the extremely cold region of −40 ° C. required for automobiles, while the inner rubber has TR10 value ≧ −20 ° C. In addition, by making the fluorocarbon rubber less than 1/2 of the outer peripheral rubber with a gasoline permeability coefficient at 40 ° C, it is excellent in gasoline resistance and fuel barrier, and is stable from low temperature to 40 ° C. A seal structure excellent in sealing performance can be provided. Also in this case, the cross-sectional shape of the seal structure is not particularly limited. A round cross-section as shown in FIG. 2, an H-shaped cross-section as shown in FIG. 5, and a modified H-shaped cross-section as shown in FIG. The TR10 value refers to the temperature at which the shrinkage rate of rubber (test piece) is 10%, and can be determined according to the low temperature elastic recovery test (TR test) of JIS K6261-1997. The gasoline permeability coefficient is constant at 40 ° C by enclosing test fuel (toluene: isooctane = 50: 50 (volume ratio)) in an aluminum container compliant with the moisture permeability test method for moisture-proof packaging materials of JIS Z0208-1976. It can be calculated by measuring the amount of the test fuel (gasoline) permeated under the atmosphere. The shape of the test piece is φ70 mm × 1 mm.
[0047]
In the case of a seal structure composed of three or more types of rubber, it is desirable that the innermost rubber and the outermost rubber have the above characteristics in order to effectively exhibit the above-described effects. However, it is not limited to these. For example, the following three combinations are applicable when described with reference to an example of a seal structure composed of three types of rubber shown in FIG.
[0048]
(1) The outer peripheral rubber 1b is a fluororubber having a TR10 value of −20 ° C. or lower, the inner peripheral rubber 1a is a fluororubber having a TR10 value of −20 ° C. or higher, and a gasoline permeability coefficient at 40 ° C. This is a case of 1/2 or less of the rubber 1b. In this case, the intermediate layer rubber 1c is not particularly limited, but it is preferable that the rubber has one of the characteristics of the inner peripheral rubber and the outer peripheral rubber.
[0049]
(2) The rubber 1c of the intermediate layer (which can be said to be one of the outer peripheral rubbers relative to the inner peripheral rubber 1a) is a fluoro rubber having a TR10 value of −20 ° C. or less, and the inner peripheral rubber 1a. This is a case where TR10 value = −20 ° C. or higher and fluoro rubber having a gasoline permeability coefficient at 40 ° C. of ½ or less of the intermediate layer rubber 1c which is the outer peripheral rubber. In this case, the outer peripheral rubber 1b is not particularly limited, but preferably has the same characteristics as the intermediate rubber 1c.
[0050]
(3) The outer peripheral rubber 1b is a fluoro rubber having a TR10 value of −20 ° C. or less, and the intermediate layer rubber 1c (for the outer peripheral rubber 1b, it can be said that it is one of the inner peripheral rubbers). This is a case where TR10 value = −20 ° C. or more and fluoro rubber having a gasoline permeability coefficient at 40 ° C. of ½ or less of rubber 1b on the outer peripheral side. In this case, the rubber 1a on the inner periphery is not particularly limited, but preferably has the same characteristics as the rubber 1c of the intermediate layer. Similarly, in the case of a seal structure composed of four or more types of rubbers, any two types of rubbers may be selected from among the four or more types of rubbers constituting the seal structure to have the above characteristics. It can be said.
[0051]
More preferably, the rubber on the inner peripheral side constituting the seal structure is a fluororubber composed of tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene (a kind of ternary FKM. Also simply referred to as ternary FKM1). ) And a rubber on the outer peripheral side thereof is a fluororubber made of tetrafluoroethylene, vinylidene fluoride, and perfluoromethyl vinyl ether (another kind of ternary FKM, also simply referred to as ternary FKM2). ).
[0052]
In this case, the above required characteristics can be established at the highest level, and procurement is stable, so that the seal structure can be supplied stably.
[0053]
In the case of a seal structure composed of three or more types of rubber, two types of rubber selected from the three or more types of rubber constituting the seal structure satisfy the requirements of the rubber material defined above. (See Example 3 to be described later). For example, the following three combinations are applicable if described with reference to an example of a seal structure composed of three types of rubber shown in FIG.
[0054]
(1) The rubber 1a on the inner peripheral side constituting the seal structure 1 is a ternary FKM1, and the rubber 1c on the outer peripheral side is a ternary FKM2. In this case, the intermediate layer rubber 1b is not particularly limited. However, since the ternary FKM1 and the ternary FKM2 are both fluorinated rubbers, different types of fluorinated rubbers are used for the intermediate layer rubber 1b. Is desirable.
[0055]
(2) The intermediate layer rubber 1b constituting the seal structure 1 (which can be said to be one of the inner peripheral rubbers relative to the outer peripheral rubber 1c) is the ternary FKM1, and the outer peripheral rubber 1c is a ternary FKM2. In this case, the inner peripheral rubber 1a is not particularly limited. However, since the ternary FKM1 and the ternary FKM2 are both fluorinated rubbers, different types of fluorinated rubbers are used for the inner peripheral rubber 1a. Is desirable.
[0056]
(3) The inner peripheral rubber 1a constituting the seal structure 1 is a ternary system FKM1, and the intermediate layer rubber 1b (for the inner peripheral rubber 1a, one of the outer peripheral rubbers Say) is the ternary FKM2. In this case, the outer peripheral rubber 1c is not particularly limited. However, since the ternary FKM1 and the ternary FKM2 are both fluorinated rubbers, different types of fluorinated rubbers may be used for the outer rubber 1c. desirable.
[0057]
The seal structure of the present invention only needs to have a structure (arrangement) in which at least two kinds of rubber are arranged concentrically with respect to the fluid flow center, and includes other structures (arrangements). It is not to exclude what is. Therefore, other structures may be included as long as the effects of the present invention are not affected. For example, as shown in FIG. 9, a part of the cross-sectional shape (structure) of the seal structure 1 is included. Furthermore, in the structure in which at least two types (or more) of rubbers are formed in series in a concentric circle with respect to the fluid flow center, or in the structure as shown in FIG. 10, that is, the cross-sectional shape (structure) of the seal structure 1 The part may have at least two kinds of rubber concentrically with respect to the fluid flow center so as to have a sea-island structure. That is, the object of the present invention can be achieved and belongs to the technical scope of the present invention.
[0058]
Furthermore, the parallel structure here may include two or more kinds of rubbers arranged side by side obliquely with respect to the axial direction of the fluid flow center. For example, FIG. 11 (A) As shown in (B), in the cross-sectional shape (structure) of the seal structure 1, two or more kinds of rubbers (in the drawing, 3 in the figure) are inclined up to 45 ° with respect to the axial direction of the fluid flow center. Various types of rubber 1a, 1b, 1c) may be provided side by side. That is, in the present invention, θ (or θ ₁ , Θ ₂ ) Is in the range of 0 ° ± 45 °, it can be said that the structures are arranged in parallel.
[0059]
Further, the in-pipe fluid is not limited to a liquid (gasoline or the like) fluid, and may be a gas fluid or a solid fluid.
[0060]
Further, as described with reference to FIG. 1, the seal structure of the present invention includes a joint portion of a fuel system pipe (tubular body) of an automobile or the like, and a joint portion of a refrigerant system pipe (tubular body) of an air conditioner. It can be applied to a wide range of industries such as a joint portion of a tubular body.
[0061]
【Example】
Hereinafter, although an example is described, the present invention is not limited to this.
[0062]
The seal structures of Comparative Examples 1 to 3 and Examples 1 to 5 were subjected to a fuel permeability test, a seal test at room temperature and a low temperature, and an adhesive strength test after fuel immersion described below, and the results shown in Table 1 Got. Further, the rubber materials constituting the seal structures of Comparative Examples 1 to 3 and Examples 1 to 5 are fluid tight (gas leaking out) under normal temperature (23 ° C.) and low temperature (−50 to −30 ° C.) atmospheres. Table 1 shows the results of measurement by the measurement methods described above or below with respect to TR10 value, TR10 value, and gasoline (Fuel C) permeability coefficient.
[0063]
(Fuel permeability test)
The fuel permeation amount measurement was performed in a sealed structure of Comparative Examples 1 to 3 to Examples 1 to 5 in an aluminum container containing test fuel (Fuel C) in which isooctane and toluene were mixed in the same volume (50:50). After being attached, it was sealed with an aluminum lid, and the weight loss of the encapsulated fuel after being left in a constant atmosphere at 40 ° C. for 504 hours (= 3 weeks) was measured. The numerical values of the fuel permeability test items in Table 1 below are the weight reduction amount (= permeation amount) of the test fuel per day (24 hr) for each seal structure (one piece) (unit: mg / piece) / Day).
[0064]
(Seal test)
After mounting the seal structures of Comparative Examples 1-3 to Examples 1-5 on an aluminum container containing commercially available regular gasoline, it was sealed with an aluminum lid and the inside was pressurized at 0.5 MPa. Under normal temperature (23 ° C.) and low temperature (−40 ° C.) atmospheres, the leakage of regular gasoline encapsulated was examined after 504 hours (3 weeks) from the start of the test (at the time of sealing pressurization).
[0065]
The leakage of regular gasoline was examined with a commercially available leak checker, but a method of examining it with a water bath may be applied. In the latter case, leakage of regular gasoline can be determined as bleeding.
[0066]
According to the criteria for determining the seal test items in Table 1 below, “No” means that no gasoline leaks (bleeding) are detected at the time of investigation (= 504 hours after the start of the test (sealing)). If a slight gasoline leak (smudge) was detected, it was judged as “Yes”. This is because the leak checker reacts if there is even a slight leak. This is because, even when checking in a water bath, if there is even a slight leak (if it is smudged), it is easy to see visually.
[0067]
(Adhesive strength test after fuel immersion)
After the seal structures of Examples 1 to 5 were immersed for 504 hours (3 weeks) in fuel heated to 60 ° C. (using regular gasoline), the seal structures were used in the fuel permeability test. After attaching to the same container and applying a tightening load, the joint portion between the rubbers of the seal structure was observed, and the presence or absence of abnormality (peeling etc.) of the joint portion was observed.
[0068]
In this test, the seal structures of Comparative Examples 1 to 3 were not tested because they were not structures in which two or more types of rubber were joined.
[0069]
(Fluidity (amount of gasoline leaking))
The fluid tightness was measured and evaluated using an O-ring under the following conditions, and the level of fluid tightness was evaluated based on the value (leakage: mg / day) obtained by the measurement. That is, the high and low fluid tightness (fluid tightness) was determined by the following measurement amount.
[0070]
・ O-ring shape: Wire diameter 3.1mm, O-ring inner diameter 130mm
・ O-ring compression ratio: 15%
・ Fuel pressure: 0.5Mpa at 23 ° C or more, no load pressure at less than 23 ° C
・ Container volume: 40ml
Measurement item: Leakage after 504 hours (mg / day)
・ Measurement method;
{Circle around (1)} 23 ° C. or higher: measured by SHED method. Specifically, an aluminum container (with an internal volume of 40 ml) containing a test fluid (gasoline was used) inside was sealed with a rubber material (both using the O-ring defined above), Pressurize the inside of the container to 0.5 MPa under (23 ° C.), and measure the amount of gasoline leaked through the O-ring (mg / day) when 504 hours (3 weeks) have passed since the start of pressurization. Small VT SHED (capacity 2m) manufactured by Japs Co., Ltd. ^Three ) Was combined with an analyzer MEXA7200 manufactured by Horiba, Ltd.
[0071]
{Circle around (2)} below 23 ° C .: measured by gravimetric method. Specifically, an aluminum container (internal volume 40 ml) in which a test fluid (gasoline was used) was placed inside was sealed with a rubber material (both using the O-ring defined above), and the temperature was lowered. (Specifically, it was carried out under three conditions of −30 ° C., −40 ° C., and −50 ° C., respectively), and leaked through the O-ring when 504 hours (3 weeks) had elapsed from the start of pressurization. The amount of leakage of the test fluid (decreasing amount of enclosed fuel; mg / day) was measured.
[0072]
-The amount of gasoline that leaks is the total amount of what leaks through the O-ring (rubber material) and leaks at the interface between the container and the O-ring.
[0073]
(TR10 value)
The temperature at which the shrinkage rate of the rubber material (test piece) was 10% was determined according to the low temperature elastic recovery test (TR test) of JIS K6261-1997.
[0074]
(Permeability coefficient of gasoline (Fuel C))
Test fuel (Fuel C; toluene: isooctane = 50: 50 (volume ratio)) is sealed in an aluminum container conforming to JIS Z0208-1976, and the test fuel gasoline (= Fuel C) in a constant atmosphere at 40 ° C. The amount of permeation was measured and calculated. The shape of the rubber material (test piece) was set to φ70 mm × 1 mm.
[0075]
(Comparative Example 1)
An O-ring having a round cross-section and a wire diameter of 3.1 mm and an inner diameter of 130 mm was used. The material was NBR.
[0076]
(Comparative Example 2)
An O-ring having a round cross-section and a wire diameter of 3.1 mm and an inner diameter of 130 mm was used. The material was a ternary FKM1.
[0077]
(Comparative Example 3)
An O-ring having a round cross-section and a wire diameter of 3.1 mm and an inner diameter of 130 mm was used. The material was ternary FKM2.
[0078]
Example 1
The cross-sectional shape is a round cross section shown in FIG. 2, and an O-ring having a wire diameter of 3.1 mm and an inner diameter of 130 mm was used. The material used was NBR-PVC for the inner material and NBR for the outer material. These adhesion methods were in-mold vulcanization adhesion methods.
[0079]
(Example 2)
The cross-sectional shape is a round cross section shown in FIG. 2, and an O-ring having a wire diameter of 3.1 mm and an inner diameter of 130 mm was used. The materials used were ternary FKM1 for the inner material and ternary FKM2 for the outer material. These adhesion methods were in-mold vulcanization adhesion methods.
[0080]
(Example 3)
The cross-sectional shape is a round cross section shown in FIG. 4, and an O-ring having a wire diameter of 3.1 mm and an inner diameter of 130 mm was used. The materials used were ternary FKM1 for the inner material, ternary FKM2 for the intermediate layer material, and NBR for the outer material. These adhesion methods were in-mold vulcanization adhesion methods.
[0081]
(Example 4)
The cross-sectional shape is a modified H-shaped cross section shown in FIG. 5, and an O-ring having an equivalent wire diameter of 3.1 mm and an inner diameter of 130 mm was used. The materials used were ternary FKM1 for the inner material and ternary FKM2 for the outer material. In these bonding methods, after preparing each part by in-mold vulcanization, these parts were bonded with a fluorine-based adhesive (manufactured by Daikin Industries, Ltd .; Daifloil # 10). Further, an O-ring having a cross-sectional shape of only the inner peripheral portion and an O-ring having a cross-sectional shape of only the outer peripheral portion are formed. After applying an adhesive over the entire circumference of these bonding surfaces, the two are pasted at 150 ° C. Bonded over 2 hours.
[0082]
(Example 5)
The cross-sectional shape is a modified H-shaped cross section shown in FIG. 5, and an O-ring having an equivalent wire diameter of 3.1 mm and an inner diameter of 130 mm was used. The materials used were ternary FKM1 for the inner material and ternary FKM2 for the outer material. These adhesion methods were in-mold vulcanization adhesion methods.
[0083]
[Table 1]

[0084]
In addition, as a note of “*” in Example 4 in the column of the adhesion strength test after fuel immersion in Table 1, there is “however, the adhesiveness at the interface between the joint portions of the inner rubber and the outer rubber is slightly weak”. In the above-mentioned adhesion strength test after immersion in fuel, the adhesion strength was generally good, but it was observed that there was a slight peeling at a part of the interface of the joining portion, so the adhesiveness was higher than that of vulcanized adhesion. In terms of weakness, the adhesiveness is weak. However, the fact that the fuel permeation performance and the seal performance are not affected is apparent from the fact that the results of the fuel permeation test and the seal test in Table 1 are good. In addition, in the case of joining by vulcanization adhesion performed in other examples, abnormalities such as peeling were not observed in the joining part, and the adhesiveness was good.
[0085]
In Example 1, when the NBRs having the same material are compared with each other, that is, when compared with Comparative Example 1, the fuel permeation amount (mg / piece / day) in the fuel permeability test is improved by 50%. It was confirmed that an NBR seal structure capable of reliably maintaining the fuel barrier property and the low temperature seal property for a long period of time can be provided.
[0086]
In Examples 2 to 5, when compared with Comparative Examples 2 and 3 of the same fluororubber material, the fuel permeability is slightly lower than that of Comparative Example 2, but at the same time, sealing performance (especially low temperature sealing performance) It is clear that the fuel permeability is improved by 30 to 40% compared to Comparative Example 3 with good sealing performance. Therefore, the fuel barrier property and low temperature sealing, which are the objects of the present invention, are achieved. It was confirmed that it is possible to provide a fluororubber seal structure that can reliably maintain the property for a long period of time.
[0087]
The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the foregoing embodiments are merely examples in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.
[Brief description of the drawings]
FIG. 1 is an example of application of a seal structure.
FIG. 2 is a cross-sectional view of a seal structure (round cross section) having a structure in which two types of rubber according to the present invention are arranged side by side (installed in parallel).
FIG. 3 is a cross-sectional view of a seal structure (circular cross section) having a structure in which three types of rubber according to the present invention are juxtaposed.
FIG. 4 is a cross-sectional view of a seal structure (round cross section) having a structure in which three types of rubber according to the present invention are juxtaposed.
FIG. 5 is a cross-sectional view of a seal structure (H cross section) having a structure in which two types of rubber according to the present invention are juxtaposed.
FIG. 6 is a cross-sectional view of a seal structure (deformation H cross section) having a structure in which two types of rubber according to the present invention are juxtaposed.
FIG. 7 is a cross-sectional view of a seal structure (H cross section) having a structure in which three types of rubber according to the present invention are juxtaposed.
FIG. 8 is a cross-sectional view of a seal structure (deformed H section) having a structure in which three types of rubber according to the present invention are juxtaposed.
FIG. 9 shows a seal structure (round section) having a structure in which two types of rubber according to the present invention are arranged side by side, and a structure in which the other two types of rubber are directly installed (installed in series). It is sectional drawing.
FIG. 10 shows a seal structure having a structure in which three types of rubber according to the present invention are juxtaposed, and a structure in which another rubber is installed in the middle layer rubber so as to form a so-called sea-island structure. It is sectional drawing of (round section).
FIGS. 11A and 11B are cross-sectional views of a seal structure (round cross section) having a structure in which three types of rubber according to the present invention are juxtaposed; It is explanatory drawing which illustrated the range of the juxtaposed structure of rubber.
[Explanation of symbols]
1 ... Seal structure,
1a ... rubber material constituting the seal structure,
1b ... rubber material constituting the seal structure,
1c ... rubber material constituting the seal structure,
2 ... Tubular body,
3 ... tubular body,
4 ... Caulking parts,
5a, 5b, 6a, 7a, 7b, 8a ... rubber contacts on the inner periphery,
5c, 5d, 6b, 7c, 7d, 8b ... rubber contacts on the outer periphery,
6c, 8c ... the lower surface of the cross-sectional shape of the seal structure,
L: Full width from the inner periphery to the outer periphery in the cross-sectional shape of the seal structure.

Claims (6)

A seal structure installed at a joint of a tubular body,
The seal structure is a structure in which at least two kinds of rubber are arranged in a concentric circle with respect to the fluid flow center,
The rubber on the inner peripheral side with respect to the fluid flow center has higher fluid tightness at room temperature than any of the rubbers positioned on the outer peripheral side,
The rubber positioned on the outer peripheral side with respect to the fluid flow center has higher fluid tightness in a temperature range of at least −30 ° C. to −50 ° C. than any of the rubber positioned on the inner peripheral side. in the sealing structure according to,
At least one of the rubbers located on the outer peripheral side is a fluororubber composed of tetrafluoroethylene, vinylidene fluoride, and perfluoromethyl vinyl ether, and a fluororubber having a TR10 value of −20 ° C. or less,
At least one of the rubbers located on the inner peripheral side of at least one of the rubbers located on the outer peripheral side is a fluororubber having a TR10 value of −20 ° C. or higher, and the rubber on the outer peripheral side with a gasoline permeability coefficient at 40 ° C. Is a fluororubber made of tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene. In the seal structure,
  The seal structure has two or more contact points that make point contact with two tubular body parts that need to be jointed with each other in order to seal fluid tightly when viewed in cross-sectional shape. The seal structure according to claim 1. In the seal structure,
The seal structure has two or more contacts that make point contact with a counterpart component in order to seal fluid tightly when viewed in its cross-sectional shape,
3. The seal structure according to claim 1, wherein at least one rubber forms one or more contacts, and at least one different rubber forms one or more different contacts. . In the seal structure,
The seal structure according to any one of claims 1 to 3 , wherein the rubber constituting the inner circumference at least with respect to the fluid flow center is fluororubber. In the seal structure,
The seal structure according to any one of claims 1 to 3, wherein the material constituting the seal structure is fluororubber.   The seal structure according to any one of claims 1 to 5, wherein two or more kinds of rubber constituting the seal structure are juxtaposed before vulcanization and bonded at the time of vulcanization. .

Images