DE4243652A1 - Flexible diaphragm for a hydraulic accumulator - is constructed from ethylene]-vinyl] alcohol copolymer layer(s) impervious to gas and elastic layer(s) contg. polyamide resin e.g nylon 6 - Google Patents

Abstract

A hydraulic accumulator is divided into two chambers, a gas chamber and a liquid chamber, by means of a flexible diaphragm. The diaphragm is formed from a number of layers with at least one layer being impervious to the gas and at least one layer which is elastically flexible. The layer which is impervious to the gas is made from copolymerised ethylene together with vinyl alcohol. The elastic layer has a main component which contains a polyamide resin which is selected from one of the groups of nylon 6, nylon 66, nylon 6-10 or nylon 6-12. ADVANTAGE - The flexible diaphragm has a long service life

Description

This invention relates to a hydraulic fluid memory in hydraulic systems for motor vehicles as well other industrial vehicles and plant components for use comes, and a flexible partition element in the form of a meme bran, a bellows or a bladder, which in such a pressure fluid reservoir is used.

A liquid reservoir fulfills the function of storing a hydraulic fluid under pressure and generally comprises a metallic housing and a flexible separating element, such as a rubber membrane or a rubber bellows or a rubber bladder, which divides the interior of the housing into a gas chamber and a liquid chamber. The membrane or bladder, which is also referred to below as a flexible partition or flexible partition element, is formed from a suitable rubber material to a desired shape with a relatively small thickness. The flexible partition is attached within the housing and interacts with the housing wall to limit the gas and liquid chamber. The gas chamber is filled with a suitable gas, such as e.g. B. N ₂ gas, while a pressure oil or pressure fluid is stored in the liquid chamber. The oil is fed into the liquid from a hydraulic pressure source, and the compressed gas acts as a damper or a spring. During use of the accumulator, the gas trapped in the gas chamber may gradually pass through or leak through the thin, flexible partition wall and become unable to function due to a reduction in gas pressure resulting from the leakage of gas through the partition wall fulfill.

A proposed solution to eliminate the above disadvantage is based on a suitable additive or suitable additi ve the rubber mixture of the flexible partition element in the Be strive to admit the resistance of separation wall to increase the gas permeability. Although the additives provide resistance to gas leakage (the gas impermeability or gas impermeability) of Partition can increase, there is a tendency to that the flexibility of the partition element decreases and this to a tearing or breaking after a relative long use time within the storage case tends. This is also a problem.

To solve this problem, it is proposed to use an ethylene Vinyl alcohol copolymer resin layer between adjacent to insert thin rubber layers of a flexible partition element conditions such that the resin layer through adhesive layers is adhesively bonded to the rubber layers. An example a multi-layer rubber / resin structure is in JP-A- 2-1 65 948. If this rubber / resin structure for a flexible membrane or bladder of a hydraulic reservoir chers is used, the ethylene vinyl alcohol allow Resin layer or layers that have a high degree of gas have impermeability that the gas filling in the storage area housing their pressure above the lower limit for a strong maintains extended memory usage time. However, the ethylene-vinyl alcohol copolymers are subject to Resin layers after a long period of use, while which deforms the membrane or bladder a number of times Going through or relocating, a tearing and one Separation from the rubber layers. As a result, life expectation of those using such a membrane or bladder Memory shortened.

An impermeable, elastic membrane is in the US-PS  50 36 110 disclosed. This membrane comprises two layers of each consisting of a first material, and a two layer that is inserted between the first layers and consists of a second material. The first material is selected from a group, the thermoplastic polyurethane ne, block amide polyether, flexible polyester and their Mi schungen comprises, while the second material from the group is selected from copolymers of ethylene and vinyl alcohol hol, polyamides, polyvinylidene chloride and mixtures thereof consists.

Although the second layer is impervious to gas, some of the first materials listed above have one insufficient heat resistance and tend to while use of a memory in which the temperature of the stored hydraulic fluid is relatively high to be damaged or destroyed. Furthermore, other first measures materials if they have a hydraulic fluid, such as a brake liquid, be exposed, soften what the ten increased to a relatively short operating time.

It is therefore a first primary object of this invention a flexible partition element for a liquid reservoir to create what is highly durable and durable dig is to ge a long service life of the memory guarantee.

A second primary object of this invention is therein hen to create a hydraulic fluid reservoir, the one has a long service life.

The first task can be done according to one aspect of this Invention to be solved, after which a flexible partition element for a liquid storage is created, that the interior of a housing of the memory in two  Divides compartments, each with a gas chamber and a river form liquidity chamber. This includes flexible separation wall element an integrated layered composite body, the at least one gas barrier layer and at least one ela contains location. The integrated layered composite body has two contiguous layers that consist of one of the at least one gas barrier layer and one of at least one elastic layer. Each of the at least one gas barrier layer is made of a copolymer sat formed by ethylene as well as ethanol and each of the contains at least one elastic layer as a main comm component of this is a polyamide resin made from a Ny lon-6, nylon-66, nylon-6-10 and nylon-6-12 existing Group is selected.

Usually two layers of rubber are covered by an adhesive on opposite surfaces of the integrated layered Adhesive composite body of the flexible partition element appropriate.

In one embodiment of the flexible partition element comprises the integrated composite body (the composite Part) a central gas barrier layer and two elastic layers conditions on opposite surfaces of the central gas barrier layer are formed. In an alternati ven embodiment of the flexible partition member comprises the integrated layered composite body has a central ela tical location and two gas barrier layers, each on opposite surfaces of the central elasti are designed.

The flexible partition element according to the invention was as he result of extensive research and study work by the Er finder that evokes your attention on a Distinguished property of a copolymer of ethylene  and vinyl alcohol (E / VAL copolymer) as a gas barrier layer, d. H. a high degree of gas impermeability (Resistance to gas passage) of the E / VAL copolymer, have judged. The central gas barrier is particularly effective layer inserted between adjacent elastic layers or the E / VAL copolymer gas barrier layers that on opposite surfaces of the central elastic are trained, powerful in that respect, a gas passes through one contained in the gas chamber of the store Gas through the integrated layered part of the flexible Prevent partition element while maintaining the central elastic layer or the elastic layers on opposite set surfaces of the central gas barrier layer as a pouf Layer or layers act to the E / VAL copolymers sat gas barrier layer or layers against tearing or to protect a separation from the adjacent layers. The Function of the elastic layer or layers seems on their Elasticity or flexibility value, which between that of the E / VAL copolymer gas barrier or -Layers and that of the rubber layers, the more common wise on the opposite surfaces of the inte are formed layers, to be attributed. As a result, the durability of the flexible partition element increased significantly, and even under working conditions of the store, at which the partition element of a repeated bending verfor tion is subjected. Consequently, the life expectancy of the Memory increased.

Because it is also a main component of the elastic layer Polyamide resin or layers used a melting point which is close to that of the E / VAL copolymer, can use the two materials for the elastic layer and the Gas barrier can be coextruded to simultaneously the adjacent or alternately designed elastic and  To form gas barrier layers or layers. React here the two materials chemically with each other, so that the Ela Stik- and gas barrier layers at their interfaces adhesive without any binder or glue be connected, due to the lack of a bindemite the elasticity of the flexible partition wall element is not subject to any negative influences however, in the presence of such an adhesive are waiting.

The ethylene-vinyl alcohol copolymer (E / VAL copolymer) can preferably consist of 20-65% by weight of ethylene, the rest or balance is ethanol. In particular is the E / VAL copolymer whose ethylene content is 32% by weight is desirable or preferable. Is the ethylene content less than 20% by weight (and the vinyl alcohol content larger than 80% by weight) is the gas barrier property of the gas barrier layer or layers increased significantly, however Flexibility reduced to a very high degree, so that the Gas barrier layer or layers is / are not able to a flexible bending deformation or misalignment close. If the ethyl content exceeds 65% by weight, then the gas barrier layer or layers is insufficient offer or show a high degree of gas barrier property.

The polyamide resin for the elastic layer or layers can be preferably selected from the group consisting of Ny lon-6, nylon-66, nylon-6-10 and nylon-6-12, where these materials used alone or in combination can be. The polyamide resin, the nylon-6 or nylon-66 has a melting point that corresponds to that of an E- / VAL- Copolymers is obvious. In this regard, the poly amide resin a mixture of nylon-6 and other nylon mate be rialien. Furthermore, the elastic layer can not more than 50% by weight, preferably about 30-40% by weight, of a poly  olefin materials such as EPM and EPDM. In this In this case, the polyolefin material acts to prevent that the E / VAL copolymer of the gas barrier layer absorbed aqueous component. If the E / VAL copolymer absorbs an aqueous component, so the gas barrier property or performance of the gas barrier deteriorates tert.

The flexural modulus of elasticity of the elastic layer, which is not contains less than 50% by weight of a polyamide resin, is between those of the rubber layers and the E / VAL copolymer Gas barrier layer. If the two elastic layers on the ent opposite surfaces of a central gas barrier layer designed, it is desirable that the bending strength Mv the E / VAL copolymer gas barrier layer and the bending plane strength M of the elastic layers can be determined to the following formulas:

Mv / M ≦ 3
Mv = 16EvL ^{× 3}
M = 16EL ³

are in here
Ev: bending modulus of elasticity of the central gas barrier layer,
Lv: thickness of the central gas barrier layer,
E: bending modulus of elasticity of the elastic layers,
L: thickness of the elastic layers.

The rubber layers that are usually opposed to each other set areas of the integrated layered composite body pers of the flexible partition element are designed, can be formed from any rubber material that usually for a flexible membrane, a flexible one Bellows or a flexible bladder for a hydraulic fluid memory is used. For example, the rubber were made of acrylonitrile butadiene rubber (NBR).  

The second task mentioned above can be done according to another aspect of this invention, after which a liquid reservoir with a housing and a flexible partition element which is arranged in the housing and divides its interior into two compartments, each of which because one is a gas chamber and the other is a liquid chamber forms, is created. The flexible dividing wall ment comprises an integrated layered composite body that has at least one gas barrier and at least contains an elastic layer, each of the at least a barrier layer of a copolymer of ethylene so such as vinyl alcohol, and each of the at least one ela layer as the main component of this is a polyamide contains resin. The integrated layered composite body around summarizes two neighboring layers, one of the least a gas barrier and one of the at least one ela existing situation.

The hydraulic fluid reservoir according to the invention has the increased durability of the flexible dividing wall , as described above, an extended Be drive or service life.

The housing or jacket of the memory is usually used se made of a suitable metal material, such as. B. Iron, steel and metal alloys, such as an Al alloy. The housing can take any desired shape for example a generally spherical, a cylindrical or a rectangular, box-like shape.

The housing can be a generally hemispherical top as well as a generally hemispherical lower part which are butted together at their open ends and welded to form a generally spherical shape to achieve education. This two-part or two-shell  Housing design enables in comparison with a ago conventional one-piece housing design a light Assembling the store. Furthermore, the inventions Education according to the application or attachment of the flexible partition element on the housing, and can be everything befe the partition element on the lower housing part be welded before the two parts are welded together will.

The memory can include a retaining ring that can be used is configured, the peripheral portion of the flexible partition wall on part of the inner peripheral surface of the lower Ge part of the house (the lower half - shell) near its (its) to fasten the fenem end. The lower half shell can be one in the above-mentioned part of the inner peripheral surface have formed throat, while the retaining ring has an Ab cut or has a piece that goes against that Throat-defining surface is caulked or pressed, and and has another piece that has the peripheral portion the partition against the inner peripheral surface of the lower Half shell of the housing presses.

The mentioned tasks and other goals as well as the Merk Male as well as advantages of this invention are from the fol Description given with reference to the drawings of preferred embodiments of the subject of the invention the clear. Show it:

Figure 1 is a partially sectioned view of a Druckflüs liquid storage in a first embodiment according to the invention.

Fig. 2 is a partial cross section of a flexible Trennwandele element in the form of a BEFE in the memory of Figure 1 BEFE flexible membrane.

Fig. 3 shows a cross section of an integrated layered composite body of the membrane of Figure 1, which consisted of a central gas barrier layer and two elastic layers.

Fig. 4 shows a cross section of part of a flexible partition in a further embodiment according to the invention;

Fig. 5 shows a partial cross section of a flexible partition in yet another embodiment of the invention;

FIGS. 6A and 6B are illustrations to the bending deformation of the diaphragm of Figure 4, when a to the membrane broke up ter oil pressure changes during an examination of the membrane of Fig. 2.

Fig. 7 is a cross sectional view of a memory in an embodiment of this invention;

FIG. 8 shows an enlarged partial section of the storage device from FIG. 7 before the fastening ring of the membrane is caulked against a lower half-shell of the storage housing;

Wherein the retaining ring is caulked against the lower half-shell 9 is a to Fig 8 is the same representation..;

Fig. 10 is a partial cross section of a flexible partition in a still further embodiment according to the invention;

Fig. 11 is a partially sectioned view of a memory containing the partition of Fig. 10;

Fig. 12 is a partial cross section of a partition in a white ter modified embodiment according to the invention.

With reference to FIGS. 1 and 2, a liquid memory in a first embodiment according to the invention will be described.

The liquid reservoir 20 has a housing 21 made of a metal material, which consists of two generally hemispherical gel-shaped parts, ie an upper half-shell 21 a and a lower half-shell 21 b, which are butt-jointed and welded to one another at their open ends delimit enclosed space. This space is divided by a flexible membrane 22 into a gas chamber 20 a on the upper and an oil or liquid chamber 20 b on the lower side of the membrane 22 . The lower half-shell 21 b takes a drain or sniffer valve 23 .

Before the two half-shells 21 a and 21 b are connected to one another by electron beam welding, the flexible membrane 22 is attached to its periphery at the open end of the lower half-shell 21 b so that the peripheral portion of the membrane 22 between a retaining ring 24 and an inner circumferential surface the open end of the lower half shell 21 b is fastened by the retaining ring 24 . After the flexible membrane 22 is attached to the lower half-shell 21 b, the two half-shells 21 a and 21 b are welded by means of an electron beam to form the generally spherical storage housing 21 .

The flexible membrane 22 consists of a central gas barrier layer 1 , two elastic layers (elastic layers) 2 formed on the opposite surfaces of the barrier layer 1 and two rubber layers 3 , each of which is configured on the outer surface of an elastic layer 2 . The central gas barrier layer 1 consists of a copolymer of ethylene and vinyl alcohol (E / VAL copolymer), while the elastic layers 2 are made of a polyamide resin. The gas barrier layer 1 and the two elastic layers 2 interact to form an integrated layered composite body. In order to produce this layered composite body 4 , the selected E / VAL copolymer and poly amide resin are co-extruded in order to simultaneously produce the central E / VAL copolymer gas barrier layer 1 and the two polyamide resin elastic layers 2 , these elastic layers 2 with the opposite ones Surfaces of the gas barrier layer 1 are bonded intimately due to a chemical reaction of the E / VAL copolymer and the polyamide resin at the contacting interfaces or interfaces. In this respect, no binder is required to form the integrated layered composite body 4 .

Then a binder or adhesive known in the relevant art is applied to the mutually opposite surfaces of the layered composite body 4 , and the rubber layers 3 are produced by pressing a suitable rubber material. The rubber layers 3 are bonded to the other opposite surfaces of the layered composite body 4 in a subsequent vulcanization of the rubber material. The flexible membrane 22 shown in FIG. 2 is produced in this way.

To further illustrate the principle of this invention, who some examples of a flexible membrane according to the Erfin tion described in comparison with comparative examples.

example 1

First, the composite body 4 layered in FIG. 3 was made. A copolymer of ethylene-vinyl alcohol (E / VAL) F-101, available from KURARAY Co. Ltd. (Japan), which contains 32% by weight of ethylene, was used for the central gas barrier layer 1 , while a polyamide resin SUPER TOUGH NYLON ST811HS, available from Du Pont, for which elastic layers 2 were used. The E / VAL copolymer and the polyamide resin were co-extruded to form the three-layer composite body 4 so that the gas barrier layer 1 had a thickness β of 50 μm and each of the two elastic layers 2 had a thickness α of 80 μm, as in the end the description attached to Table 1 is given.

Then the three-layer composite body 4 thus produced was coated on its opposite surfaces with a known adhesive, and the rubber layers 3 were formed from NBR by pressing and vulcanizing. Each rubber layer 3 had a thickness of 1790 microns, just as is shown in Table 1. In this way, the five-layer flexible membrane 2 shown in Fig. 2 was Herge. It is desirable that the thickness α of each elastic layer 2 and the thickness β of the central gas barrier layer 1 be determined so that the formula α / β ≧ 1 is satisfied.

Example 2

An integrated seven-layer composite body 6 shown in FIG. 4 was produced by co-extrusion using the same materials as in Example 1. The composite body 6 consists of the three-layer composite body 4 of FIG. 3, two outer gas barrier layers 1 ', which are ausgebil det on the elastic layers 2 (inner elastic layers), and two outer elastic layers 2 ', each of which is configured on an outer gas barrier layer 1 ' are. As indicated in the attached table 1 , all gas barrier layers 1 , 1 'have the same thickness of 50 µm and the inner elastic layers 2 have the same thickness of 50 µm, while the outer elastic layers 2 ' have the same thickness of 80 µm. It is desirable that the thickness α of each outer elastic layer 2 ', the thickness β of each gas barrier layer 1 and 1 ' and the thickness γ of each inner elastic layer 2 be determined so that the following formulas are satisfied: α / β ≧ 1 and 0.1 ≦ γ / β ≦ 3.5.

A one-piece, elf-layer composite body 8 shown in FIG. 5 was manufactured by coextruding using the same materials as in Examples 1 and 2. The composite body 8 consists of the three-layer Ver composite body 4 of FIG. 3, two intermediate gas barrier layers 1 'on the composite body 4 , two intermediate elastic layers 2 on the intermediate gas barrier layers 1 ', two outer gas barrier layers 1 'on the intermediate elastic layers 2 and two outer elastic layers 2 'on the intermediate outer gas barrier layers 1 '. Then the NBR layers 3 were designed on the outer elastic layers 2 ', so that a flexible membrane 28 with thirteen layers, as shown in Fig. 5, was generated.

Layers 1 , 1 'and layers 2 , 2 ' have the thickness values given in Table 1. It is desirable that the thickness α of the outer elastic layer 2 ', the thickness β of each gas barrier layer 1 , 1 ' and the thickness γ of each inner or intermediate elastic layer 2 be determined such that the inequalities α / β ≧ 1 and 0, 1 ≦ α / β ≦ 3.5, as in Example 2, can be met.

Comparative Examples 1 and 2

Two comparative samples were made. Any pattern consists of a central gas barrier layer, which is protected by Ex the same E / VAL copolymer that is used in the case of play 1 - 3 was used, manufactured, and two NBR layers, which are obtained by pressing and gluing with an adhesive tel to the opposite surfaces of the gas barrier layer were formed. The thickness of the gas barrier layer and the gum Milages of the two samples are given in Table 1.

The flexible membranes 22 , 26 and 28 of Examples 1, 2 and 3 as well as the samples or test pieces of Comparative Examples 1 and 2 were evaluated for flexibility and resistance to tearing and gas passage. The flexibility was examined by bending the samples according to the invention and the comparison samples by hand. In order to examine or test the patterns for the tear resistance of the E / VAL copolymer gas barrier layers, the patterns were set in an apparatus shown in Figs. 6A and 6B. During the endurance test, one of the chambers on the side of the sample or sample membrane was charged with N ₂ gas, while the hydraulic pressure applied to the other chamber was changed cyclically in order to repeat the bending deformation of the membrane, as in FIGS . 6A and 6B is shown to bring about. The size of the N ₂ gas permeability through the sample membranes was measured in an initial stage of the endurance test and after the end of the test. The results of the flexibility test and the endurance tests are given in the attached Table 2.

In the endurance test performed using the apparatus shown in Figs. 6A and 6B, the hydraulic pressure applied to each sample membrane alternated between 2.5 times that of N ₂ gas and 3 times that of N ₂ gas changed to effect a bending deformation or displacement of the test pieces. This pressure change cycle was repeated a million times with a frequency of 0.3 Hz at 80 ° C.

From the attached Table 2 it is clear that the flexible membranes 22 , 26 and 28 according to this invention showed considerably better results than the comparative examples.

Referring to Figs. 7-9, a memory 100 will be described which incorporates the flexible membrane of Fig. 2. The memory 100 , which is similar in structure to the memory 20 of FIG. 1, has a substantially spherical metal housing which consists of an upper half-shell 110 and a lower half-shell 112 , as shown in FIG. 7. The memory 100 was assembled in the manner described below.

First, the flexible membrane 22 , the peripheral portion 22 a is somewhat thickened, as shown in Fig. 8, arranged inside the lower half-shell 112 so that the peripheral portion 22 a by a retaining ring 103 on the inner peripheral surface of the half-shell 112 close the upper end of which was fixed. The lower half-shell 112 was then welded to the upper half-shell 110 .

For the purpose of fastening the flexible membrane 22 , the lower half-shell 112 was designed in its inner circumferential surface near its upper end piece with a circumferential groove 113 and a strip or rib 114 surrounding this groove 113 , as shown in FIG. 8. The retaining ring 103 has a stepped configuration with a large-diameter piece 103 a, a small-diameter piece 103 b, and a shoulder portion 103 c on. To attach the membrane 22 , this and the retaining ring 103 were first arranged so that the peripheral portion 22 a of the membrane 22 came into contact with a part of the inner circumferential surface of the lower half-shell 112 , which is spaced a certain distance from the circumferential throat 113 , and that the large-caliber piece 103 a of the ring 103 came into contact with part of the inner peripheral surface in which the throat 113 is formed, while the small-caliber piece and the shoulder piece 103 b and 103 c with the thick-walled peripheral portion 22 a of the membrane 22nd were in plant. In this state, the retaining ring 103 was 113 facing portion caulked at one of the throat of the latter, so that this part was pressed against the surface of the throat 113 as shown in Fig. 9 is shown. In this way, the peripheral portion 22 a of the membrane 22 from the outer surface of the small-caliber piece 103 b and the shoulder piece 103 c of the ring 103 was detected and firmly clamped between these pieces and the inner surface of the lower half-shell 112 . The presence of the circumferential groove 113 and the caulking of the ring 103 ensure a strong, permanent fastening of the membrane 22 and increase the fluid tightness between the membrane 22 and the lower half-shell 112 , as a result of which passage and leakage of gas and hydraulic fluid through the Interface between the membrane 22 and the lower half-shell 112 can be prevented. The ledge or rib 114 formed under the throat 113 ensures a precise positioning of the retaining ring 103 and the membrane 22 with respect to the lower half-shell 112 .

After the flexible membrane 22 was attached to the lower half-shell 112 , the upper and lower half-shells 110 , 112 were butted against each other at their open end faces, as shown in FIG. 7, to thereby delimit a generally spherical housing of the memory 100 . At this point in time, the condition of the attachment of the membrane 22 to the lower half-shell 112 can be checked in terms of its quality before the lower half-shell 112 is closed by the upper half-shell 110 . The two half-shells 110 and 112 were welded to one another at their end faces by means of an electron beam welding technique, as indicated by 101 e in FIG. 7. Since the weld seam 101 e is spaced a considerable distance from the peripheral section 22 a of the membrane 22 , the peripheral section 22 a is protected against an adverse influence by the heat generated during the welding.

In the manner described, the memory 100 was manufactured, which has a gas chamber 101 a limited by the membrane 22 and the upper half-shell 110 and a liquid or oil chamber 101 b limited by the membrane 22 and the lower half-shell 112 . A drain or sniffer valve 121 connected to the lower side of the membrane 22 is accommodated in the memory 100 . An oil connection piece 151 has a Ölka nal 150, which communicates with the oil chamber 101 in communication with the gas chamber 101 a a gas connection pipe 153 is connected. The position of the membrane 22 when it is elastically deformed is indicated by dash-dotted lines in FIG. 7.

Referring to FIGS. 10 and 11 abgewan punched embodiment will be explained this invention wherein a memory 30, a flexible membrane 32 is used, the inte grated laminated composite body 14 to the integrated layered composite bodies 4, 6 and 8, reciprocating in the front Embodiments are used, is different. The membrane 32 cooperates with the housing 21 men to delimit a gas chamber 30 a and a liquid or oil chamber 30 b.

As shown in Fig. 10, the integrated layered composite body 14 consists of five layers, namely a central Ela stiklage 11 , the main component of which is a polyamide resin, two gas barrier layers 12 made of an E / VAL copolymer, which on the opposite surfaces of the central Ela Stiklage 11 are formed, and two outer elastic layers 11 ', which are each formed on a gas barrier layer 12 . The integrated, five-layer composite body 14 is made by co-extruding the selected polyamide resin and E / VAL copolymer to simultaneously form the central elastic layer 11 and the gas barrier layers 12 and outer elastic layers 11 'on each of the two sides of the central elastic layer 11 . No adhesives are used to manufacture the integrated, five-layer composite body 14 of the membrane 32 . Two rubber layers 13 are verbun with the outer surfaces of the outer elastic layers 11 '. The membrane 32 produced in this way is fixed in the housing 21 of the memory 30 , as shown in Fig. 11 ge.

Examples 4 and 5

First, the five-layer composite body 14 was made by coextruding the same materials for the gas barrier layers 12 and the elastic layers 11 and 11 'as used in Examples 1-3, so that the E / VAL copolymer gas barrier layers 12 on each other opposite surfaces of the central polyamide resin elastic layer 11 and the outer polyamide resin elastic layers 11 'were formed on the respective gas barrier layers 12 . The layers 11 , 11 'and 12 in Examples 4 and 5 have the thickness values given in Table 3 added.

Subsequently, the five-layer composite body 14 produced in this way was coated on its mutually opposite surfaces with a known binder, whereupon the NBR layers 13 were formed by pressing and vulcanizing. These rubber layers 13 have the thickness values given in Table 3. The seven-layer flexible membrane 32 shown in FIG. 10 was thus produced in the manner described.

Comparative Examples 3-7

Five comparative samples were made. Every pattern of Comparative Examples 3-5 consist of five layers or layers ten, d. H. a central E / VAL copolymer gas barrier layer, which is formed by extrusion, two polyamide resin elastic which were also extruded at the central gas barrier layer are formed, and two NBR layers through Have been manufactured and by an adhesive with the  opposite surfaces of the central E / VAL copoly merisat gas barrier layer were adhesively bonded. The sample Examples 6 and 7 consist of three layers, i. H. one central E / VAL copolymer gas barrier layer and two NBR Locations. The E / VAL copolymer, the synthetic resin and the NBR Rubber that has been used is the same as that used in Examples 4 and 5 were used. The thickness values the layers or layers included in the comparison samples are given in Table 3.

The flexible membranes 32 of Examples 4 and 5 and the samples of Comparative Examples 3-7 were evaluated for flexibility and resistance to tearing and gas penetration in the same manner as that above with reference to Examples 1-3 and Comparative Examples 1 and 2 has been described. The results of the flexibility and endurance tests are also shown in Table 3.

From Table 3 it is clear that the membranes 32 according to Examples 4 and 5 are not subject to cracks in the gas barrier layers 12 .

Fig. 12 shows a flexible membrane 34 , which is a modification of the membrane 32 of FIG. 10. The membrane 34 has an integrated, nine-layer composite body 16 , which comprises: the five-layer composite body 14 of the membrane 32 of FIG. 10, two outer E / VAL copolymer gas barrier layers 12 , which on the intermediate polyamide resin elastic layers 11 'of the five-layer composite body 14 are formed, and two outer polyamide resin elastic layers 11 'on the two outer E / VAL copolymer gas barrier layers 12th The two NBR layers 13 are on the outer elastic layers 11 'tet. Thus, the membrane 34 consists of two inner gas barrier layers 12 , two outer gas barrier layers 12 , one with term elastic layer 11 , two intermediate elastic layers 11 'and two outer elastic layers 11 '.

Although this invention is detailed based on its counter currently preferred embodiments has been explained, so these explanations only serve to illustrate the Invention and it is clear that the invention is not limited to the details shown and described are limited, but can be realized in a different way.

In the examples described, each of the membranes 22 , 26 , 28 , 32 and 34 has two rubber layers 3 and 13 on the opposite sides of the integrated layered composite body 4 , 6 , 8 , 14 and 16th However, the rubber layers can be left out.

Although the housing of the memory 20 , 30 and 100 shown in FIGS. 1, 7 and 11 is on the whole kugelför shaped, this housing can take a different shape, such as. B. that of a cylinder or a rectangular box. Furthermore, the housing of the memory shown consists of two parts in the form of the upper and lower half shells 21 a, 110 and 21 b, 112 ; however, the housing may be a one-piece construction having an opening through which the membrane or bladder can be mounted within the housing.

The invention discloses a flexible partition element for a hydraulic fluid reservoir, which an interior divides a housing of the memory into two compartments form a gas chamber and a liquid chamber. The flexible partition element includes an integrated ge layered composite body, the at least one gas contains barrier layer and at least one elastic layer.  

Each gas barrier layer consists of a copolymer of Ethylene and vinyl alcohol, and each elastic layer contains as a major component of this is a polyamide resin that is made from is selected from a group that includes nylon-6, nylon-66, nylon 6-10 and nylon 6-12. The integrated history tete composite body contains two adjacent layers made of a gas barrier layer and an elastic layer. Dar in addition, the invention turns a hydraulic fluid memory revealed that with a flexible dividing wall ment of the type described above.

With knowledge of the mediated by this, the invention can Teaching with various changes, modifications and verbs realizations are realized, the expert suggests are, however, as falling within the scope of the invention you can see.  

Table 1

Table 2

Table 3

Claims (20)

1. Flexible partition element for a liquid memory, which divides the interior of a housing ( 21 , 110 , 112 ) of the memory into two compartments, each forming a gas chamber ( 20 a, 101 a) and a liquid chamber ( 20 b, 101 b) , characterized in that the flexible partition element ( 22 , 26 , 28 , 32 , 34 ) comprises an integrally layered composite body ( 4 , 6 , 8 , 14 , 16 ) which has at least one gas barrier layer ( 1 , 1 ', 12 ) and at least contains an elastic layer ( 2 , 2 ', 11 , 11 '), the integrally layered composite body having two adjoining layers, which consist of one of the at least one gas barrier layer and one of the at least one elastic layer, each of the at least one gas barrier layer of one Copolymer of ethylene and vinyl alcohol is gebil det and each of the at least one elastic layer as a main component of this contains a polyamide resin consisting of one of nylon-6, nylon-66 , Nylon-6-10 and Nylon-6-12 existing group is selected from. 2. Partition element according to claim 1, characterized in that the at least one gas barrier layer comprise a central gas barrier layer ( 1 ) and the at least one elastic layer two elastic layers ( 2 ), the central gas barrier layer ( 1 ) between the two elastic layers ( 2 ) inserted and in contact with them. 3. partition element according to claim 1, characterized in

• - That the at least one gas barrier layer comprises a central gas barrier layer ( 1 ) and two outer gas barrier layers ( 1 '),
• -that the at least one elastic layer comprises two inner elastic layers ( 2 ) and two outer elastic layers ( 2 '),
• - That the central gas barrier layer ( 1 ) between the two inner elastic layers ( 2 ) inserted and in contact with them and
• - that the two outer gas barrier layers' are formed at each weils one of the two inner elastic layers (2), while the two outer elastic La gen (2 (1) 'layers) to each one of the two outer gas barrier (1') formed are.

4. partition element according to claim 1, characterized in

• - That the at least one gas barrier layer comprises a central gas barrier layer ( 1 ), two intermediate gas barrier layers ( 1 ') and two outer gas barrier layers ( 1 '),
• - That the at least one elastic layer comprises two inner elastic layers ( 2 ), two intermediate elastic layers ( 2 ) and two outer elastic layers ( 2 '),
• - That the central gas barrier layer ( 1 ) is inserted between the two inner elastic layers ( 2 ) and is in contact with them,
• - That the two intermediate gas barrier layers ( 1 ') are each formed on one of the two inner elastic layers ( 2 ),
• - That the two intermediate elastic layers ( 2 ) are each formed on one of the two intermediate gas barrier layers ( 1 '),
• - That the two outer gas barrier layers ( 1 ') are each formed on one of the two intermediate elastic layers ( 2 ) and
• - That the two outer elastic layers ( 2 ') are each ausgebil det on one of the two outer gas barrier layers ( 1 ').

5. partition element according to claim 1, characterized in that the at least one elastic layer comprises a central elastic layer ( 11 ) and two outer elastic layers ( 11 ') that the at least one gas barrier layer comprises two gas barrier layers ( 12 ) that the central elastic layer ( 11 ) between the two gas barrier layers ( 12 ) inserted and in contact with them and that the two outer elastic layers ( 11 ') are each formed because one of the two gas barrier layers ( 12 ). 6. partition element according to claim 1, characterized in

• - That the at least one elastic layer comprises a central elastic layer ( 11 ), two intermediate elastic layers ( 11 ') and two outer elastic layers ( 11 '),
• - That the at least one gas barrier layer comprises two inner gas barrier layers ( 12 ) and two outer gas barrier layers ( 12 ),
• - That the central elastic layer ( 11 ) between the two inner gas barrier layers ( 12 ) is inserted and with which sen in contact,
• - That the two intermediate elastic layers ( 11 ') are each formed on one of the two inner gas barrier layers ( 12 ),
• - That the two outer gas barrier layers ( 12 ) are formed on the two intermediate elastic layers ( 11 ') and
• - That the outer elastic layers ( 11 ') are formed on the two outer gas barrier layers ( 12 ).

7. partition element according to claim 2, characterized in that each of the two elastic layers ( 2 , 2 ') and the mitti ge gas barrier layer ( 1 ) each have thickness values α and β which meet α / β ≧ 1. 8. partition element according to claim 3 or 4, characterized in that each of the outer elastic layers ( 2 ') and the central gas barrier layer each have thickness values α and β which meet α / β ≧ 1. 9. partition element according to claim 8, characterized in that each layer ( 2 ) of the at least one elastic layer ( 2 , 2 ') with the exception of the outer layer ( 2 ') has a thickness γ which is 0.1 ≦ α / β ≦ 3.5 fulfilled. 10. Partition element according to one of claims 1 to 9, characterized by two rubber layers ( 2 , 13 ) which are adhesively connected by an adhesive with mutually opposite surfaces of the integrally layered composite body ( 4 , 6 , 8 , 14 , 16 ). 11. partition element according to one of claims 1 to 10, characterized in that the copolymer of Ethylene and vinyl alcohol from 20-65% by weight of ethyl len and ethanol as the rest.   12. Partition element according to one of claims 1 to 11, characterized in that each layer ( 2 , 2 ', 11 , 11, ) from the at least one elastic layer essentially from not less than 50 wt .-% of the polyamide resin and not more than 50% by weight of a polyolefin material. 13. Liquid reservoir with a housing ( 21 , 110 , 112 ) and a flexible partition element ( 22 , 26 , 28 , 32 , 34 ) which is arranged in the housing and divides the interior space into two compartments, one of which is a gas chamber ( 20 a, 101 a) and the other forms a liquid chamber ( 20 b, 101 b), characterized in that the flexible partition element ( 22 , 26 , 28 , 32 , 34 ) has an integrated layered composite body ( 4 , 6 , 8 , 14 , 16 ), which contains at least one gas barrier layer ( 1 , 1 ', 12 ) and at least one elastic layer ( 2 , 2 ', 11 , 11 '), the integrated layered composite body having two adjoining layers which are made of one of the at least one gas barrier layer and one of the at least one elastic layer, each of the at least one gas barrier layer is formed from a copolymer of ethylene and vinyl alcohol and each of the at least one elastic layer as a main component e contains a polyamide resin selected from a group consisting of nylon-6, nylon-66, nylon-6-10 and nylon-6-12. 14. The memory of claim 13, characterized in that the housing has a generally hemispherical upper shell ( 21 a, 110 ) and a generally hemispherical lower shell ( 21 b, 112 ) which abut one another at their open ends and are welded to one another, and a holding ring ( 24 , 103 ) which defines a peripheral portion ( 22 a) of the flexible partition member ( 22, 26, 28, 32, 34 ) on a part of the inner peripheral surface of the lower shell ( 21 b, 112 ) near the open end thereof, includes. 15. The memory according to claim 14, characterized in that the generally hemispherical lower shell ( 112 ) has a throat ( 113 ) formed in said part of the inner circumferential surface and the retaining ring ( 103 ) is a piece which is caulked against a surface determining the throat ( 103 a) and another, the peripheral portion ( 22 a) of the flexible partition element against the inner peripheral surface of the lower shell ( 112 ) pressing piece ( 103 b, 103 c). 16. Memory according to one of claims 13 to 15, characterized in that the flexible partition element ( 22 , 26 , 28 , 32 , 34 ) consists of a flexible membrane which together with the housing ( 21 , 110 , 112 ) on it opposite sides of the liquid and gas chambers ( 20 b, 101 b, 20 a, 101 a) limited. 17. Memory according to one of claims 13 to 16, characterized in that the at least one gas barrier layer a central gas barrier layer ( 1 ') and the at least one elastic layer two elastic layers ( 2 ) to take, the central gas barrier layer ( 1 ) between the inserts two elastic layers ( 2 ) and is in contact with them. 18. Memory according to one of claims 13 to 16, characterized in that the at least one elastic layer comprises a central elastic layer ( 11 ) and the at least one gas barrier layer comprise two gas barrier layers, the central elastic layer being inserted between and with the two gas barrier layers is in contact. 19. Memory according to one of claims 13 to 18, characterized characterized in that the copolymer of ethylene so such as vinyl alcohol from 20-65% by weight of ethylene and Vi nyl alcohol as the rest. 20. Memory according to one of claims 13 to 19, characterized in that each layer ( 2 , 2 ', 11 , 11 ') from the at least one elastic layer essentially from not less than 50 wt .-% of the polyamide resin and no more than 50% by weight of a polyolefin material.