JP4937072B2 - Diaphragm and accumulator using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm capable of inhibiting the generation of a crack of a resin layer and excellent in durability. <P>SOLUTION: The diaphragm 20 is provided with a resin layer 21 for gas shielding, a gas chamber side rubber layer 22 and an oil chamber side rubber layer 23 formed at both sides of the resin layer 21. The resin layer 21 and the gas chamber side rubber layer 22, and the resin layer 21 and the oil chamber side rubber layer 23 are glued by a chlorinated polybutadiene rubber adhesive. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a diaphragm used for a hydraulic apparatus (hydraulic suspension, hydraulic automatic clutch, power steering, etc.) for automobiles, industrial vehicles, and the like, and an accumulator using the diaphragm.

  BACKGROUND ART A hydraulic accumulator using a characteristic that a volume is expanded and compressed by a gas load pressure is used in a hydraulic device such as an automobile (for example, a hydraulic suspension, a hydraulic automatic clutch, a power steering, etc.). This accumulator has a pressure accumulating function, and generally comprises a metal shell and a diaphragm that is disposed in the shell and divides the internal space of the shell into two chambers (a gas chamber and an oil chamber). A gas such as nitrogen gas is sealed in the gas chamber, and the oil chamber is connected to the hydraulic circuit of the hydraulic device through the circulation hole for use. When the pressure of the oil chamber becomes larger than the pressure of the gas chamber due to the hydraulic oil flowing into the oil chamber from the flow hole, the diaphragm is bent and elastically deformed, whereby the gas chamber is compressed and the volume is increased. As it becomes smaller, the oil chamber is enlarged and hydraulic oil is accumulated.

As the diaphragm used in the accumulator, a rubber diaphragm has been used from the viewpoint of volume efficiency, weight, and cost. In recent years, in order to prevent gas permeation and leakage through the rubber diaphragm, a resin layer made of, for example, polyamide resin or ethylene-vinyl alcohol copolymer (EVOH) for gas shielding, A diaphragm made of a composite material of resin and rubber, comprising a gas chamber side rubber layer formed on the gas chamber side through the oil chamber side and an oil chamber side rubber layer formed on the oil chamber side through the resin layer Has been mass-produced. The rubber material forming both rubber layers is selected according to the type of oil used in the hydraulic circuit. For example, in the case of mineral oil, acrylonitrile-butadiene rubber ( Rubber materials such as NBR), hydrogenated NBR (H-NBR), and epichlorohydrin rubber are used (for example, see Patent Document 1).
JP 2001-254701 A

  In conventional diaphragms, the resin layer and the gas chamber side rubber layer, and the resin layer and the oil chamber side rubber layer are usually bonded with a chlorinated polyolefin adhesive or the like. In order to strengthen the adhesion with the resin layer, a large amount of a co-crosslinking agent is blended. For this reason, the adhesive layer becomes hard due to heat or the like during vulcanization. And the bending of the diaphragm at the time of use, etc. causes a crack in the adhesive layer, which propagates to the resin layer, and has the disadvantage that the durability of the product is inferior.

  This invention is made | formed in view of such a situation, The objective of this invention is to provide the diaphragm which can suppress generation | occurrence | production of the crack of a resin layer, and was excellent in durability, and an accumulator using the same.

  In order to achieve the above object, the present invention is a diaphragm comprising a gas shielding resin layer, a gas chamber side rubber layer and an oil chamber side rubber layer formed on both surfaces of the resin layer, A diaphragm in which the resin layer and the gas chamber side rubber layer, and the resin layer and the oil chamber side rubber layer are bonded with a chlorinated polybutadiene rubber adhesive is a first gist.

  Moreover, this invention makes a 2nd summary the accumulator provided with the shell and the said diaphragm which divides the internal space of this shell into a gas chamber and an oil chamber.

  That is, the present inventors have made extensive studies in order to obtain a diaphragm that can suppress the occurrence of cracks in the resin layer and has excellent durability. First, for chlorinated polyolefin adhesives that have been used in the past, the experiment was repeated with the amount of the co-crosslinking agent reduced, but the occurrence of cracks could not be sufficiently suppressed, and the adhesiveness was insufficient. there were. Therefore, focusing on rubber-based (elastomer-based) adhesives with excellent flexibility, and as a result of continuing experiments, the use of chlorinated polybutadiene rubber-based adhesives can suppress the occurrence of cracks in the resin layer and have excellent durability. The present invention has been found.

  Thus, in the diaphragm of the present invention, the resin layer and the gas chamber side rubber layer, and the resin layer and the oil chamber side rubber layer are bonded to each other by the chlorinated polybutadiene rubber adhesive. Since this chlorinated polybutadiene rubber-based adhesive is superior in flexibility and liquid resistance as compared with conventional chlorinated polyolefin-based adhesives, the occurrence of cracks in the adhesive layer itself is very small. Therefore, it is difficult for cracks to propagate to the resin layer, the occurrence of cracks in the resin layer can be suppressed, and the durability of the product is excellent.

  Next, embodiments of the present invention will be described in detail.

  An example of an accumulator using the diaphragm of the present invention is shown in FIG. This accumulator is configured using shells 1 and 2 and a diaphragm 20 that divides the internal space of the shells 1 and 2 into a gas chamber 3 and an oil chamber 4. In FIG. 1, 5 is a ring-shaped holding material, 6 is a poppet, 7 is a plug having an oil port 8, 9 is a gas plug, and 10 is an electron beam weld. Moreover, in FIG. 1, the broken line has shown the state which the diaphragm 20 deform | transformed.

  As the shells 1 and 2, for example, those made of iron or aluminum alloy are preferably used.

  For example, as shown in FIG. 2, the diaphragm 20 includes a gas shielding resin layer 21, and a gas chamber side rubber layer 22 and an oil chamber side rubber layer 23 integrally formed on both surfaces of the resin layer 21. It consists of three layers.

  Here, in the present invention, the resin layer 21 and the gas chamber side rubber layer 22, and the resin layer 21 and the oil chamber side rubber layer 23 are bonded with a chlorinated polybutadiene rubber adhesive, This is the greatest feature of the present invention.

  As a rubber component of the chlorinated polybutadiene rubber-based adhesive, chlorinated polybutadiene rubber is used as a main component, but is not limited thereto.

  The chlorinated polybutadiene rubber-based adhesive may be appropriately mixed with additives other than rubber components such as chlorinated polybutadiene rubber. Examples of additives other than the rubber component include titanium dioxide, dichlorohydrin, and carbon black. These may be used alone or in combination of two or more.

  Next, examples of the gas chamber side rubber layer 22 include acrylonitrile-butadiene rubber (NBR), hydrogenated acrylonitrile-butadiene rubber (H-NBR), butyl rubber (IIR), halogenated butyl rubber (Cl-IIR, Br). -IIR, etc.), rubber compositions containing rubber components such as epichlorohydrin rubber, ethylene-propylene rubber (EPM, EPDM) and the like are used. These rubber components are used alone or in combination of two or more.

  In addition to the rubber component such as H-NBR, the rubber composition forming the gas chamber side rubber layer 22 contains carbon black, vulcanizing agent, anti-aging agent, plasticizer, zinc oxide, stearic acid and the like. It may be blended appropriately. These may be used alone or in combination of two or more.

  Examples of the oil chamber side rubber layer 23 include acrylonitrile-butadiene rubber (NBR), hydrogenated acrylonitrile-butadiene rubber (H-NBR), butyl rubber (IIR), and halogenated butyl rubber (Cl-IIR, Br— IIR, etc.), rubber compositions containing rubber components such as epichlorohydrin rubber, ethylene-propylene rubber (EPM, EPDM) and the like are used. These rubber components are used alone or in combination of two or more.

  In addition to the rubber component such as H-NBR, carbon rubber, vulcanizing agent, anti-aging agent, plasticizer, zinc oxide, stearic acid and the like are appropriately added to the rubber composition forming the oil chamber side rubber layer 23. It can be blended with. These may be used alone or in combination of two or more.

  The resin layer 21 prevents the gas sealed in the gas chamber 3 from passing therethrough, and the material for forming the resin layer 21 is not particularly limited as long as the material has low gas permeability. For example, ethylene -Vinyl alcohol copolymer (EVOH), polyamide resin, polyvinylidene fluoride, polyvinylidene chloride, polyphenylene sulfide, liquid crystal polymer, polyethylene naphthalate and the like. These may be used alone or in combination of two or more. The resin layer 21 may have a single layer structure using the above forming material or a multilayer structure of two or more layers.

  Although it does not specifically limit as said EVOH, It is preferable to use what has an ethylene content of 20 to 65 weight%, and the remainder consists of vinyl alcohol. Of these, those having an ethylene content of 32% by weight are preferred.

  Examples of the polyamide resin include nylon 6, nylon 66, nylon 6-10, nylon 6-12, and the like. These may be used alone or in combination of two or more. Since such a polyamide resin approximates the melting point of EVOH if the above nylon 6 or nylon 66 is in the base, various mixtures of nylon 6 and other nylon resins can be used. is there. In particular, the polyamide resin and the polyolefin resin are preferably blended and used. If it does in this way, since polyolefin resin is scarce in water absorption, it comes to prevent water absorption with respect to EVOH. That is, when EVOH absorbs water, the gas barrier resistance decreases, and the polyolefin resin prevents this.

  The diaphragm 20 of the present invention can be manufactured as follows, for example. That is, first, a resin layer (resin film) 21 for gas shielding is produced by singly or in combination of two or more types of resin films having low gas permeability such as EVOH and polyamide resin. Next, a chlorinated polybutadiene rubber-based adhesive is applied to both the upper and lower surfaces of the resin layer (resin film) 21, and both layer forming materials of the gas chamber side rubber layer 22 and the oil chamber side rubber layer 23 are pressed by a press. Molded and vulcanized. In this way, a diaphragm 20 having a three-layer structure as shown in FIG. 2 can be manufactured.

  Examples of the method for applying the chlorinated polybutadiene rubber adhesive include dipping, spraying, and brushing.

  In the diaphragm 20 of the present invention thus obtained, the resin layer (resin film) 21 has a thickness of usually 50 to 210 μm. Moreover, each thickness of the said gas chamber side rubber layer 22 and the oil chamber side rubber layer 23 is 1-4 mm normally, respectively, Preferably it is 1-1.5 mm each. The thickness of the adhesive layer (not shown) made of the chlorinated polybutadiene rubber adhesive is preferably in the range of 2 to 30 μm, particularly preferably in the range of 5 to 10 μm.

  The accumulator of the present invention can be manufactured using the diaphragm 20 having the above-described configuration, for example, as follows. That is, first, the diaphragm 20 manufactured as described above is formed on the inner peripheral edge of the opening of the lower divided shell 2 out of the two substantially hemispherical divided shells 1 and 2, as shown in FIG. The peripheral edge is positioned, and the peripheral edge is clamped and fixed between the outer periphery of the ring-shaped holding member 5 and the inner peripheral edge of the opening of the lower divided shell 2, and is attached to the lower divided shell 2. Next, the opening of the upper divided shell 1 is abutted against the opening of the lower divided shell 2, and electron beam welding or the like is performed. In this way, an accumulator as shown in FIG. 1 can be manufactured.

  In addition, the shape of the shell in the accumulator of the present invention is not limited to the one in which two substantially hemispherical shell-shaped divided shells 1 and 2 as shown in FIG. For example, various shapes such as a substantially shell shape, a cylindrical shape, and a box shape can be used.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

  First, prior to Examples and Comparative Examples, rubber compositions were prepared.

[Preparation of rubber composition 1]
The components shown in Table 1 below were blended in the proportions shown in the same table, and these were kneaded with a roll to prepare a rubber composition.

  The materials shown in Table 1 are as follows.

[H-NBR]
Made by Nippon Zeon Co., Ltd., Zetpole 3110 (AN amount: 25% by weight)

〔Carbon black〕
Dia Black E manufactured by Mitsubishi Chemical Corporation

(Anti-aging agent (1))
Sumilyzer MB, manufactured by Sumitomo Chemical
(Anti-aging agent (2))
Nouchi CD, manufactured by Ouchi Shinsei Chemical Co., Ltd.

[Vulcanizing agent (peroxide)]
Perkadox 14-40, manufactured by Kayaku Akzo

[Plasticizer]
Dioctyl phthalate, manufactured by Chisso Corporation

  Next, a diaphragm was produced using the rubber composition.

[Example 1]
First, EVOH (ethylene content 32%) and polyamide resin (PA) (nylon 6) were prepared, and these were coextruded to form a 5-layer resin of PA / EVOH / PA / EVOH / PA with a total thickness of 2 mm. A layer (resin sheet) was prepared. Next, after wiping the surface with isopropyl alcohol (IPA) and dipping the chlorinated polybutadiene rubber-based adhesive (P6EF, manufactured by Rohm and Haas), air-drying the adhesive layer on both the upper and lower surfaces of the resin layer (Thickness 10 μm) was formed. Next, each rubber composition shown in Table 2 below is used as a material for forming the gas chamber side rubber layer and the oil chamber side rubber layer on the surface of the adhesive layer. Partial vulcanization adhesion. Thus, a rubber-resin laminate sheet (diaphragm) having a gas chamber side rubber layer thickness of 1.3 mm and an oil chamber side rubber layer thickness of 1.3 mm was produced.

[Comparative Example 1]
Instead of the chlorinated polybutadiene rubber adhesive, a chlorinated polyolefin adhesive (C6108, manufactured by Road Far East Co., Ltd.) was used. Other than that was carried out similarly to Example 1, and produced the rubber-resin laminated sheet (diaphragm).

  The example product and the comparative product obtained in this way were evaluated for their characteristics according to the following criteria. The results are also shown in Table 2 above.

〔Evaluation of the physical properties〕
Each rubber-resin laminate sheet was immersed in mineral oil-based oil (Pentosine CHF-11S) for 70 hours under each temperature condition of 100 ° C., 120 ° C., and 150 ° C., then taken out, punched out with JIS No. 3 dumbbell, and JIS According to the method described in K6250, the strength at break (TS) and the elongation at break (EB) were measured. Note that the strength at break (TS) and the elongation at break (EB) were also measured before oil immersion (blank).

[Adhesion peel test]
A rubber-resin laminate sheet was produced in the same manner as in Examples and Comparative Examples. At this time, about 1/3 of the sheet was masked with a film to prepare a chuck portion for a 180 degree peel test. Then, each rubber-resin laminate sheet was immersed in mineral oil-based oil (Pentosine CHF-11S) for 70 hours under each temperature condition of 100 ° C., 120 ° C., and 150 ° C., and then taken out. And a 180 degree peel test was conducted. In addition, the 180 degree | times peeling test was similarly done before oil immersion (blank).

[State of resin layer]
The appearance of the resin layer after the adhesion peel test was visually observed. In the evaluation, “X” indicates that many cracks occurred in the resin layer, “◯” indicates that the resin layer has very few cracks, and “◎” indicates that no crack occurred in the resin layer.

  From the results of Table 2 above, the product of Comparative Example 1 using the chlorinated polyolefin-based adhesive was greatly deteriorated in physical properties due to heat load compared to the product of Example 1 using the chlorinated polybutadiene rubber-based adhesive. Further, when the appearance of the resin layer after the adhesion peel test was observed, in the product of Comparative Example 1, the curing phenomenon of the adhesive layer was extremely fragile, and many cracks were generated in the resin layer. In contrast, the product of Example 1 was able to suppress the occurrence of cracks in the resin layer because the adhesive layer was flexible.

  The diaphragm and accumulator of the present invention can be used for hydraulic devices (hydraulic suspension, hydraulic automatic clutch, power steering, etc.) for automobiles, industrial vehicles and the like.

It is a figure (partial cross section) which shows an example of the accumulator of this invention. It is a principal part expanded sectional view which shows an example of the diaphragm of this invention.

Explanation of symbols

20 Diaphragm 21 Resin layer 22 Gas chamber side rubber layer 23 Oil chamber side rubber layer

Claims (2)

  A diaphragm comprising a gas shielding resin layer and a gas chamber side rubber layer and an oil chamber side rubber layer formed on both surfaces of the resin layer, the resin layer, the gas chamber side rubber layer, and a resin A diaphragm characterized in that the layer and the oil chamber side rubber layer are bonded with a chlorinated polybutadiene rubber adhesive.   An accumulator comprising a shell and a diaphragm that divides the inner space of the shell into a gas chamber and an oil chamber, wherein the diaphragm comprises the diaphragm according to claim 1.

Images