DE102004036481B4 - Vehicle brake system component - Google Patents

Abstract

Vehicle brake system component (1) such as a pressure accumulator used in a brake system of a vehicle, the vehicle brake system component (1) comprising: a pressure vessel (2) with a gas chamber (11), in which a gas is enclosed, and a liquid chamber ( 12) which is filled with a liquid; a membrane (3) which has a fixed end (3a) attached to the pressure vessel (2) and a free end (3b) which extends in the direction of an axis (L) of the pressure vessel ( 2) can expand and contract and is arranged in the pressure vessel (2) to separate the gas chamber (11) and the liquid chamber (12), a partition (5) which is arranged in the liquid chamber (12) and one Circulation port (15) through which the liquid flows into and out of the liquid chamber (12) when the membrane (3) expands or contracts; anda sealing element (6) which closes the circulation connection (15) in a liquid-impermeable manner in order to enclose the liquid between the partition wall (5) and the membrane (3) when the membrane (3) expands and contracts by a given stroke, wherein the sealing element (6) comprises a metal element (21), an adhesive layer (22) provided on the metal element (21), which is assigned to at least a part of the surface of the metal element (21), and an elastic rubber element connected to the metal element (21) (23), with the adhesive layer (22) in between, characterized in that the adhesive layer (22) has a first adhesive layer (22a) that is in contact with the metal element (21) and a second adhesive layer (22b) that is provided on the first adhesive layer (22a), the first adhesive layer (22a) and the second adhesive layer (22b) being fixed in such a way that the proportions by weight of chlorine and a sulfo group therein not more than 11.0% or not more than 1.0%.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a vehicle brake system component, such as a pressure accumulator used in a brake system of a vehicle.

A conventional vehicle brake system component, e.g. B. a pressure accumulator, comprises a pressure vessel and a membrane. The pressure vessel contains a gas chamber in which a compressed gas is enclosed and a liquid chamber which is filled with a liquid such as oil. The membrane separates the gas and liquid chambers and has an end that can expand and contract in the axial direction of the vessel. The membrane of the pressure accumulator of this type must have an elasticity in order to cope with a change in volume of the gas as well as a high effectiveness as a gas barrier (high gas impermeability). Therefore, the membrane is required to be compliant and long-lasting.

In the case of the pressure accumulator, in which the interior of the pressure vessel is divided by the membrane into the gas and liquid chambers, the membrane can sometimes expand or contract excessively if the gas is enclosed in the gas chamber or if the pressure in the liquid chamber during the Use falls below a given level. If the membrane expands or contracts excessively in this manner, it is partially pressed against the inner surface of the pressure vessel. As a result, an unacceptable force may act locally on a sealing member provided on an elastic end, thereby losing the effectiveness of the sealing or sealing performance.

A conventional pressure accumulator is in the JP S64- 79 439 A described. In this pressure accumulator, a partition is arranged in a liquid chamber and a cover (sealing element) is provided on an elastic end of a membrane. The partition has a circulation connection at a point opposite the elastic end of the membrane. Oil flows out of an oil chamber through the circulation connection when the membrane expands or contracts, the connection being in communication with the oil chamber. The lid is made of a rubber-like, elastic body made of synthetic resin.

According to this pressure accumulator, when the membrane is completely expanded or contracted, part of the oil already stored in the liquid chamber is enclosed by the cover on the liquid chamber side of the membrane (between the partition and the membrane). Because the fluid is essentially incompressible, the enclosed support fluid or oil prevents the membrane from expanding or contracting further.

The sealing element for enclosing the supporting liquid is always immersed in a liquid introduced into the liquid chamber. The pressure accumulator is used in a hydraulic pressure device that is installed, for example, in a vehicle. Therefore, the sealing element should preferably be able to ensure satisfactory sealing performance in the long term, as well as chemical resistance and resistance to pressure fluctuations at high temperature. However, the conventional sealing member is difficult to ensure satisfactory sealing performance over a long period of time.

BRIEF SUMMARY OF THE INVENTION

The present invention has been accomplished in view of these circumstances, and its object is to provide a vehicle brake system component that can ensure sealing performance in the long term.

A vehicle brake system component of the invention is intended to solve the problem of ensuring sealing performance in the long term.

A vehicle brake system component according to a first aspect of the invention is used in a vehicle brake system and includes a sealable composite component that includes a metal member and an elastic rubber member connected and arranged so that they are in contact with a brake fluid.

The vehicle brake system component according to the first aspect of the invention includes the sealable composite component that includes the metal member and the elastic rubber member that are connected to each other and arranged to be in contact with the brake fluid. Therefore, the sealing performance of the composite component can be ensured in the long term.

The composite component preferably contains the metal element, an adhesive layer provided on the metal element, which is assigned to at least part of the surface of the metal element, and the elastic rubber element connected to the metal element, the adhesive layer being located between them. With this arrangement, the sealing performance of the composite component can be ensured in the long term.

A vehicle brake system component according to a second aspect of the invention is a component such as a pressure accumulator used in a brake system of a vehicle. The brake system component includes: a pressure vessel having a gas chamber in which a gas is enclosed and a liquid chamber which is filled with a liquid; a diaphragm having a fixed end attached to the pressure vessel and a free end that can expand and contract in the direction of an axis of the pressure vessel and is arranged in the pressure vessel to separate the gas chamber and the liquid chamber; a partition disposed in the liquid chamber and having a circulation port through which the liquid flows into and out of the liquid chamber as the membrane expands or contracts; and a sealing member that closes the circulation port in a liquid-impermeable manner to trap the liquid between the partition and the membrane when the membrane expands and contracts by a given stroke. The sealing element contains a metal element, an adhesive layer provided on the metal element, which is assigned to at least a part of the surface of the metal element, and an elastic rubber element connected to the metal element, the adhesive layer being located between them.

In the vehicle brake system component according to the second aspect of the invention, the sealing member includes the metal member, the adhesive layer provided on the metal member associated with at least a part of the surface of the metal member, and the elastic rubber member connected to the metal member with the adhesive layer therebetween . Therefore, the sealing performance of the composite component can be ensured in the long term.

The metal element preferably has a metal element body and a protective layer, which is provided on the surface of the metal element body and prevents a drop in quality of the metal element body. With this arrangement, the protective layer prevents corrosion of the surface of the metal element body, so that a deterioration in the quality of the metal element by oxidation and a weakening of the adhesive function between the metal element and the elastic rubber element can be prevented in the long term.

The protective layer is preferably a zinc-calcium phosphate layer with a crystal grain size of at most 8 μm. With this arrangement, the peel strength at the interface between the metal member and the adhesive layer can be improved.

The metal element and the elastic rubber element are preferably connected to one another by vulcanization bonding using the adhesive layer. With this arrangement, the metal member and the elastic rubber member can be more firmly connected.

The adhesive layer includes a first adhesive layer that is in contact with the metal element and a second adhesive layer that is provided on the first adhesive layer. More specifically, the layer of adhesive includes the first layer of adhesive that is in contact with the metal member and the second layer of adhesive that is provided on the first layer of adhesive and is in contact with the rubber member. With this arrangement, the metal element and the elastic rubber element can be more firmly connected to one another, with the layer of adhesive with the first and second layers of adhesive in between.

The first layer of adhesive is preferably fixed such that the weight fraction of a hydroxyl group therein is at least 10%. With this arrangement, the peel strength between the metal member and the adhesive layer can be improved by hydrogen bonding at the interface between the metal member and the adhesive layer.

The first and second adhesive layers are determined so that the proportions by weight of chlorine and a sulfo group therein are at most 11.0% and at most 1.0%. With this arrangement, the sealing performance of the sealing member or the composite component can be maintained in the long term.

The thickness of the first layer of adhesive is preferably in the range from 1 μm to 15 μm, while the thickness of the second layer of adhesive is in the range from 4 μm to 21 μm. With this arrangement, the first and second layers of adhesive can each spread out evenly. In addition, these layers of adhesive can be prevented from becoming brittle. Thus, a satisfactory peel strength can be obtained between the metal member and the rubber member, so that the sealing performance of the sealing member or the composite component can be maintained satisfactorily for a long time.

Preferably the first layer of adhesive is a phenolic resin layer while the second layer of adhesive is a chlorinated EPDM resin layer. With this arrangement, the sealing performance of the sealing member or the composite component can be maintained satisfactorily for a long time.

Preferably, the elastic rubber member is made of elastic rubber which has a hardness greater than SHORE A 80 specified by JIS (Japanese Industry Standard) K6253 and a tensile strength of at least 20 MPa. With this arrangement, the sealing member or the composite component can maintain its satisfactory sealing performance for a long time even after repeated use.

According to the present invention, a vehicle brake system component can be created, the effectiveness of which is ensured in the long term.

Further objects and advantages of the invention will be set forth in the description which follows, some of which will become apparent from the description, or may be learned by practice of the invention. The objects and advantages of the invention can be achieved and achieved with the means and combinations which are particularly emphasized below.

Figure list

• 1 ist eine Schnittansicht, die einen Druckspeicher als Fahrzeug-Bremssystemkomponente gemäß einer ersten Ausführungsform der Erfindung zeigt;
• 2 ist eine Schnittansicht, die ein Dichtungselement des Druckspeichers nach 1 zeigt;
• 3 ist eine Schnittansicht, die ein weiteres Beispiel des Dichtungselements zeigt, das an dem Druckspeicher nach 1 angebracht werden kann;
• 4 ist ein Grundriss, der eine bei einer Abziehfestigkeitsprüfung verwendete Probe zeigt;
• 5 ist eine Schnittansicht, die die bei der Abziehfestigkeitsprüfung verwendete Probe zeigt;
• 6 ist ein Diagramm, das die Beziehung zwischen der Eintauchzeit des Dichtungselements der ersten Ausführungsform, das eine Klebstofflage verwendet, und der Abziehfestigkeit zwischen einem Metallelement und einem elastischen Gummielement im Vergleich zu einem Dichtungselement, das eine Klebstofflage verwendet, als Vergleichsbeispiel zeigt;
• 7 ist ein Diagramm, das die Beziehung zwischen der Eintauchzeit des Dichtungselements der ersten Ausführungsform, das einen metallischen Werkstoff verwendet, und der Abziehfestigkeit zwischen einem Metallelement und einem elastischen Gummielement im Vergleich zu einem Dichtungselement, das einen metallischen Werkstoff verwendet, als Vergleichsbeispiel zeigt;
• 8 ist eine Schnittansicht, die einen Hauptzylinder als Fahrzeug-Bremssystemkomponente gemäß einer zweiten Ausführungsform der Erfindung zeigt;
• 9 ist eine vergrößerte Schnittansicht, die ein Mittelventil des Hauptzylinders nach 8 und seine Umgebung zeigt;
• 10 ist eine Schnittansicht, die den Hauptzylinder nach 8 zeigt, wobei sein Auslassanschluss durch das Mittelventil verschlossen ist;
• 11 ist eine Schnittansicht, die eine Tauchkolbenpumpe als Fahrzeug-Bremssystemkomponente gemäß einer dritten Ausführungsform der Erfindung zeigt; und
• 12 ist eine vergrößerte Schnittansicht, die eine Öldichtung der Tauchkolbenpumpe nach 11 und ihre Umgebung zeigt.

The accompanying drawing, which is incorporated in and forms a part of the specification, shows currently preferred embodiments of the invention and, together with the general description given above and the detailed description given below, serves to explain the principles of the invention.

• 1 Fig. 12 is a sectional view showing an accumulator as a vehicle brake system component according to a first embodiment of the invention;
• 2nd is a sectional view showing a sealing member of the accumulator according to 1 shows;
• 3rd Fig. 12 is a sectional view showing another example of the sealing member attached to the accumulator after 1 can be attached;
• 4th Fig. 4 is a plan view showing a sample used in a peel strength test;
• 5 Fig. 12 is a sectional view showing the sample used in the peel strength test;
• 6 Fig. 11 is a graph showing the relationship between the immersion time of the seal member of the first embodiment using an adhesive sheet and the peel strength between a metal member and an elastic rubber member compared to a seal member using an adhesive sheet as a comparative example;
• 7 Fig. 12 is a graph showing the relationship between the immersion time of the seal member of the first embodiment using a metallic material and the peel strength between a metal member and an elastic rubber member compared to a seal member using a metallic material as a comparative example;
• 8th Fig. 12 is a sectional view showing a master cylinder as a vehicle brake system component according to a second embodiment of the invention;
• 9 Fig. 3 is an enlarged sectional view showing a center valve of the master cylinder 8th and shows its surroundings;
• 10th is a sectional view showing the master cylinder 8th shows, its outlet port is closed by the center valve;
• 11 Fig. 12 is a sectional view showing a plunger pump as a vehicle brake system component according to a third embodiment of the invention; and
• 12th Fig. 3 is an enlarged sectional view showing an oil seal of the plunger pump 11 and shows their surroundings.

DETAILED DESCRIPTION OF THE INVENTION

With regard to the 1 and 2nd a first embodiment of the present invention will now be described. In connection with the present embodiment, an accumulator as a vehicle brake system component is explained.

As in 1 is shown, comprises a pressure accumulator 1 as a vehicle brake system component, a pressure vessel 2nd , a metallic bellows 3rd as a membrane, a cap section 4th , a partition 5 , a sealing element 6 etc. The sealing element 6 also serves as a sealable composite component.

The accumulator 1 is used to store pressure generated in a hydraulic pressure device and to absorb the hydraulic pulsation. In the following description of the present embodiment, it is assumed that the accumulator is used as a hydraulic pressure device in a hydraulic brake device as a vehicle brake system that is attached to a vehicle such as a car.

The pressure vessel 2nd has a first and a second shell 7 and 8th on. Each of the first and second shells 7 and 8th is a bottomed cylinder formed by forging or the like. The outside and inside diameters of an open end of the first shell 7 essentially correspond to those of an open end of the second shell 8th . The first bowl 7 has in its bottom section (upper part in 1 ) a gas inlet 7a on. The second bowl 8th has in its bottom section (lower part in 1 ) an opening 8a on. The second bowl 8th also has a connection 9 through which a liquid is introduced into the vessel from the braking device. A support collar 9a for attaching a fixed end 3a (mentioned later) of the bellows 3rd stands by the connection 9 horizontally outwards. The connection 9 is in the opening 8a the second bowl 8th fitted with its support collar 9a in the bowl 8th is held.

The respective end portions of the first and second shells 7 and 8th are resistance welded with current flowing between them and under pressure in their axial direction. This will make the shells 7 and 8th assembled in a gas-tight manner. The pressure vessel 2nd that from the first and second bowl 7 and 8th Assembled and assembled in this way is stiff enough to withstand the working pressure of the braking device on the accumulator 1 acts to resist.

The pressure vessel 2nd contains a gas chamber 11 and a liquid chamber defined therein 12th . The bellows 3rd separates the gas chamber 11 and the liquid chamber 12th and is in the vessel 2nd arranged. The bellows 3rd has the fixed end 3a that on the pressure vessel 2nd is attached, and a free end 3b that extends in the direction of an axis L of the vessel 2nd can expand and contract. The firm end 3a of the bellows 3rd is by welding or the like to the entire circumference of the support collar 9a connected in an air and liquid impermeable manner. The cap section 4th has a flat, bottomed cylinder portion 4a with a low profile and a collar section 4b that of an open end of the cylinder section 4a stands horizontally outwards. The free end 3b of the bellows 3rd is with the entire circumference of the collar section 4b of the cap section 4th connected by welding or the like in an air and liquid impermeable manner.

The interior of the pressure vessel constructed in this way 2nd is in two chambers, the gas chamber 11 and the liquid chamber 12th , divided. The gas chamber 11 is from the outer surface of the bellows 3rd , the inner surface of the pressure vessel 2nd and the outer surface of the cap portion 4th (on the side of the first bowl 7 ) surround. The liquid chamber 12th is from the inside surface of the bellows 3rd and the inner surface of the cap portion 4th (on the side of the second bowl 8th ) surround.

In the gas chamber is above the gas inlet 7a Nitrogen gas or inert gas included. After trapping the gas in the gas chamber 11 becomes the gas inlet 7a through a sealing plug 13 hermetically sealed. In 1 denotes the reference symbol 14 a cover covering the stopper 13 surrounds. The liquid chamber 12th stands over the connection 9 in connection with the braking device. The interior of the liquid chamber 12th is filled with a fluid or a brake fluid from the Brake device is initiated. The pressure of the brake fluid in the brake device thus acts on the fluid chamber 12th a.

The partition 5 is in the liquid chamber 12th intended. The wall 5 has a disc-shaped end wall 5a that are parallel to the base of the cap section 4th extends, and a cylindrical peripheral wall 5b . The wall 5 divides the interior of the liquid chamber 12th in two areas, a first area that connects to the brake unit 9 communicates, and a second area from the inner surface of the bellows 3rd and the partition 5 is surrounded. The end wall 5a has a circulation connection 15 through which the liquid in the liquid chamber 12th flows between the first and the second region.

The sealing element 6 to close the circulation connection 15 is in a liquid impervious manner within the cap section 4th arranged. The sealing element 6 is the end wall 5a facing. On the collar section 4b of the cap section 4th is an annular holding plate by spot welding or the like 16 appropriate. The retention plate 16 prevents the sealing element 6 from the cap section 4th slips out. If the bellows 3rd contracts by a given stroke, the sealing element 6 between the cap section 4th and the end wall 5a squeezed so that the fluid (the brake fluid) is between the partition 5 (Peripheral wall 5b) and the bellows 3rd is included (see 1 ).

That part (hereinafter referred to as the reception seat 17th designated) the end wall 5a that with the sealing element 6 is engaged, is flat. The reception seat 17th can be a little roughened to provide a satisfactory sealing effect between the sealing element 6 and the seat 17th ensure. On that part of the sealing element 6 that with the receiving seat 17th is engaged is a head start 6a educated. This engagement part can be flat.

The following is a description of how the accumulator works 1 .

Before the gas in the gas chamber 11 is included, the brake fluid from the brake device via the connection 9 into the liquid chamber 12th headed. The pressure of the brake fluid causes the bellows 3rd expands so that the sealing element 6 from the reception seat 17th the partition 5 is separated. As a result, the circulation connection 15 open. If the connection 15 is open, the gas is through the gas inlet 71 into the gas chamber 11 headed.

When the gas is introduced in this way, the bellows pulls 3rd by the pressure of the gas supplied gradually together, the sealing element 6 in the reception seat 17th engages as in 1 is shown. As a result, the circulation connection 15 closed. If the connection 15 is closed, is the space occupied by the bellows 3rd and the partition 5 is hermetically sealed so that the brake fluid between the bellows 3rd and the partition 5 is included. The fluid is essentially incompressible. When the pressure in the gas chamber 11 further increases, it is thus from the brake fluid (support oil), which is between the bellows 3rd and the partition 5 is trapped. Consequently, no undue force can be applied locally to the bellows 3rd act.

In this way, the gas enters the gas chamber 11 initiated until the pressure in the chamber 11 a given pressure of e.g. B. 20 MPa or more. Then the gas inlet 7a with the sealing plug 13 hermetically sealed.

The pressure on the inside of the partition 5 the liquid chamber 12th acts on the sealing element 6 if it turns up during the accumulator 1 works, increased due to the fluctuation of the fluid pressure in the braking device. This pressure presses on the sealing element 6 , whereupon the circulation connection 15 opens and the bellows 3rd expands. The bellows 3rd extends a span that corresponds to the pressure in the liquid chamber 12th corresponds, whereupon the pressures in the liquid chamber 12th and the gas chamber 11 are balanced. If the pressure on the inside of the partition 5 the liquid chamber 12th decreases, the pressure pushes from the gas chamber 11 on the cap section 4th , whereupon the bellows 3rd contracts. The bellows 3rd contracts by a range that corresponds to the pressure in the liquid chamber 12th corresponds, whereupon the pressures in the chambers 12th and 11 are balanced. These processes of action absorb the fluctuation in the pressure in the braking device.

When the pressure in the liquid chamber 12th to a given or lower pressure, ie to a level lower than the pressure in the gas chamber 11 is, the bellows pulls down 3rd together, so the sealing element 6 with the receiving seat 17th engaged. As a result, the circulation connection 15 closed. If the connection 15 is closed, is the space occupied by the bellows 3rd and the partition 5 is hermetically sealed, so that the pressures in the second area of the liquid chamber 12th and the gas chamber 11 are balanced. Thus the bellows 3rd improved durability without the possibility of being subjected to an unacceptable local force.

The following is a detailed description of the sealing element 6 . As in 2nd shown contains the sealing element 6 a disc-shaped metal element 21 , an adhesive layer 22 and an elastic rubber element 23 . The metal element 21 has a metal element body 21a and a protective layer 21b on. The protective layer covers the entire surface of the metal element body 21a and serves to decrease the quality of the body 21a to prevent. The adhesive layer 22 is provided so that it covers the entire surface of the metal element 21 , ie the entire surface of the protective layer 21b , covered. The elastic rubber element 23 is with the metal element 21 connected, with the adhesive layer in between 22 located. In other words, the metal element 21 is through the rubber element 23 covered, with the location in between 22 located. For example, EPDM (ethylene-propylene-diene-methylene copolymer) for the rubber element 23 be used appropriately.

The protective layer 21b does not always have the entire surface of the metal element body 21a cover, but only at least part of the surface of the body 21a be assigned assigned. As for example in 3rd is shown, the protective layer 21b between the metal element body 21a and the adhesive layer 22 be provided. The location 22 and the rubber element 23 do not always have the entire surface of the metal element 21 cover, but only at least part of the surface of the metal element 21 be assigned assigned. As for example in 3rd is shown, the adhesive layer 22 on a surface of the disc-shaped metal element 21 be arranged. In this case, the rubber element 23 which has a size equal to that of one surface of the metal element 21 corresponds with the element 21 connected, with the adhesive layer in between 22 located.

The following is a description of the adhesive layer 22 . Preferably the metal element 21 and the elastic rubber element 23 connected by vulcanization bonding. According to this procedure, they are connected to each other when the rubber element 23 is poured. More specifically, vulcanization bonding is preferably applied so that the adhesive layer 22 between the rubber element 23 and the metal element 21 is placed. This allows the two elements 21 and 23 be more firmly connected.

The adhesive layer preferably contains 22 a first layer of adhesive 22a (Sub-layer or primer) with the metal element 21 (the protective layer 21b) is in contact, and a second layer of adhesive thereon 22b (Top layer or top layer).

A fluid that easily absorbs water, such as ethylene glycol ether, is often used as the brake fluid. Accordingly, the adhesive layer 22 be selected considering their water resistance. Preferably the adhesive layer 22 therefore be free of chlorine (CL), a sulfo group (-SO ₃ H) or other components that are chemically relatively unstable. The second layer of adhesive 22b For example, should be formed from a resin based on chlorinated EPDM (ethylene-propylene-diene-methylene copolymer), as will be explained below. However, many existing resins based on chlorinated EPDM contain 15.0% by weight or more of chlorine or 2.0% by weight or more of the sulfo group. According to the present embodiment, therefore, are both the first layer of adhesive 22a as well as the second layer of adhesive 22b from chlorine and the sulfo group, where far removed, that they contain at most 11.0% by weight of chlorine and at most 1.0% by weight of the sulfo group.

6 shows the relationship between the immersion time of the sealing member 6 and the peel strength between the metal member 21 and the elastic rubber element 23 . In 6 represent the curves S and T measurement results that were obtained when using samples S and T, respectively.

• Probe S (Dichtungselement 6 der vorliegenden Erfindung): Dichtungselement mit einer Lage von Harz, das auf chloriniertem EPDM basiert, das 11,0 Gew.-% oder weniger Chlor und 1,0 Gew.-% der Sulfogruppe enthielt (wobei die anderen Bedingungen wie bei dem Dichtungselement 6 der vorliegenden Ausführungsform waren),
• Probe T (Vergleichsbeispiel): Dichtungselement mit der Klebstofflage 22, die 15,0 Gew.-% oder mehr Chlor oder 2,0 Gew.-% oder mehr der Sulfogruppe enthielt (wobei die anderen Bedingungen wie bei dem Dichtungselement 6 der vorliegenden Ausführungsform waren),
• Tauchflüssigkeit: Bremsfluid, das 5 Vol.-% Wasser enthielt,
• Bremsfluidtemperatur: 120 °C.

The test was carried out under the following conditions.

• Sample S (sealing element 6 of the present invention): Sealing member with a layer of resin based on chlorinated EPDM containing 11.0% by weight or less of chlorine and 1.0% by weight of the sulfo group (the other conditions being the same as the sealing member 6 the present embodiment),
• Sample T (comparative example): sealing element with the adhesive layer 22 containing 15.0% by weight or more of chlorine or 2.0% by weight or more of the sulfo group (the other conditions being the same as the sealing member 6 the present embodiment),
• Immersion fluid: brake fluid containing 5 vol.% Water,
• Brake fluid temperature: 120 ° C.

The following is a description of a method for measuring peel strength. This peel strength test was carried out on a sample (hereinafter referred to as a cross pattern) in which the metal element 21 and the elastic rubber element 23 were put together like a cross, with the adhesive layer between them 22 was like in the 4th and 5 is shown. The metal element 21 had the dimensions 20 mm by 50 mm by 3.2 mm. The rubber element 23 was in an atmosphere of 120 ° C at a speed of 10 mm / min in one to the metal element 21 pulled in the opposite direction.

The inventors were able to demonstrate that the sealing performance of the sealing element 6 decreased when the peel strength of the sealing element 6 decreased so that the brake fluid (support oil) between the bellows 3rd and the partition 5 was not included satisfactorily. It was also confirmed that the sealing performance of the sealing element 6 slightly decreased when its peel strength decreased to 32% or less of its initial value. In 6 the breaking strength is shown as the point at which the peel strength between the metal element 21 and the elastic rubber element 23 Is 32% of its initial value.

In the case of Sample T (comparative example), the peel strength after 100 hours of immersion was about 3 MPa and fell below the breaking strength when the immersion time was about 200 hours.

In the case of sample S (sealing element 6 the present embodiment), on the other hand, the peel strength after about 300 hours of immersion was about 3 MPa and remained about 2.5 MPa even after 500 hours of immersion without falling below the breaking strength. Subsequently, the peel strength slowly decreased, whereby the adhesiveness between the metal element 21 and the elastic rubber element 32 held at 40% or more of the initial peel strength after 300 hours of immersion.

The adhesion between the metal element 21 and the elastic rubber element 23 can be improved by for the first layer of adhesive 22a and the second layer of adhesive 22b Adhesives are used that are attached to the metal element 21 (the protective layer 21b and the metal element body 21a) or on the elastic rubber element 23 are strongly binding.

Preferably for the first layer of adhesive 22a (Primer) uses a polar resin attached to the metal element 21 can adhere. The first layer of adhesive should be more preferred 22a be formed from an adhesive attached to the protective layer 21b or the metal element body 21a is strongly binding and has excellent heat resistance and chemical resistance. For the adhesive layer 22a For example, phenolic resin, epoxy resin, etc. can be used.

The second layer of adhesive 22b (Top layer) is used to connect a relatively rigid resin for the first layer of adhesive 22a with the elastic rubber element 23 , which is made of soft rubber or an elastomer. Therefore, for the second layer of adhesive 22b an elastic body based on rubber or an elastomer is suitable.

Should be preferred again as a second layer of adhesive 22b an adhesive that with the elastic rubber element 23 is tolerated, should be chosen. For example, as an adhesive layer 22 a layer of a copolymer mainly composed of ethylene, propylene, diene and methylene can be used.

The second layer of adhesive should be preferred again 22b both on the elastic rubber element 23 as well as the polar resin (e.g. phenolic or epoxy resin) used for the first layer of adhesive 22a is suitable to be adhesive. In other words, the adhesive layer 22b should have an affinity for both the first layer of adhesive 22a as well as the rubber element 23 have.

The solubility coefficient (SP value) is a well-known index that indicates the affinity of two components. The SP value is defined as the square root of the energy required per unit volume to separate a molecule from a molecular complex of each component (cohesive energy density). Thus, components that have approximately the same SP values have excellent affinity and wettability to each other. Table 1 shows the respective SP values of various synthetic rubbers, brake fluid (e.g. polyethylene glycol) and water. The SP values of chlorinated EPDM and chlorinated polyethylene vary depending on their chlorination rates. Table 1 SP values of various synthetic rubbers Rubber type SP value Ethylene propylene rubber 7.9 Chlorinated EPDM (C1) 8.3-9.3 Chlorinated polyethylene rubber (C0) 8.2-9.0 Hydride rubber 9.1 Chloroprene rubber 9.2 Acrylic rubber 9.4 Nitrile rubber 9.6 Urethane rubber 10.0 Brake fluid (Potyethytenglycol) 14.6 water 23.4

As described above, for the elastic rubber member 23 for example EPDM (ethylene-propylene-diene-methylene copolymer) can be used suitably. Therefore, for the second layer of adhesive 22b For example, a component with an SP value that is between that of phenolic resin ( 11 , 3) that for the first layer of adhesive 22a and that of EPDM (7.9), which is used for the rubber element 23 is suitable, lies, be used suitably. As a result, chlorinated EPDM resin (or chlorinated EPDM rubber), chlorinated polyethylene resin (chlorinated polyethylene rubber), etc. can be used for the second adhesive layer 22b be used appropriately. If for the rubber element 23 If EPDM is used, chlorinated EPDM, whose chemical structure is the same as that of EPDM, is assumed to be more excellent. If for the second layer of adhesive 22b Chlorinated EPDM or polyethylene resin is used, however, should be the thickness of the first layer of adhesive 22a and the second layer of adhesive 22b preferably selected in the following manner to ensure adhesion to the first layer of adhesive 22a balance.

The following is a description of the studies of the thicknesses of the first layer of adhesive 22a and the second layer of adhesive 22b . Table 2 shows results of evaluations of the thickness and the coating conditions of adhesives. Table 3 shows measurement results for peel strength after immersion tests using cross patterns. Table 4 shows test results for peeling conditions after the immersion tests using cross patterns. Table 5 shows the rate of remaining peel strength (the rate of retention of peel strength) after the immersion tests using the cross pattern. The peel strength was measured under the same conditions as mentioned above. Table 2 Adhesive layer thickness and coating conditions (conditions for the primer and the top layer shown in the order given in each column, o: good, x: too uneven for use) primer Typical layer thickness 0.5 µm 2 µm 4 µm 7 µm 10 µm 14 µm 17 µm Typical layer thickness Layer thickness range <1 µm 1-3 µm 3-5 µm 6-8 µm 9-11 µm 13-15 µm 16-24 µm Top layer 2 µm 1-4 µm x, x o, x o, x ο, x o, x o, x x, x 5 µm 4-6 µm x, o o, o o, o o, o o, o o, o x, o 8 µm 7-9 µm x, ο o, o o, o o, o o, o o, o, x, o 10 µm 9-11 µm x, o o, o o, o o, o o, o o, o x, o 15 µm 14-16 µm x, o o, o o, o o, o o, o o, o x, o 20 µm 19-21 µm x, o o, o o, o o, o o, o o, o x, o 25 µm 22-28 µm x, x o, x o, x o, x o, x o, x x, x Table 3 Peel strength after immersion test, based on cross pattern primer Typical layer thickness 0.5 µm 2 µm 4 µm 7 µm 10 µm 14 µm 17 µm Typical layer thickness Layer thickness range <1 µm 1-3 µm 3-5 µm 6-8 µm 9-11 µm 13-15 µm 16-24 µm Top layer 2 µm 1-4 µm untestable untestable untestable untestable untestable untestable untestable 5 µm 4-6 µm untestable 5.5 5.7 5.7 5.4 4.5 untestable 8 µm 7-9 µm untestable 5.3 5.8 5.6 5.7 3.1 untestable 10 µm 9-11 µm untestable 5.2 5.4 5.7 5.1 2.7 untestable 15 µm 14-16 µm untestable 2.8 3.9 3.7 3.9 2.7 untestable 20 µm 19-21 µm untestable 3.0 3.5 4.5 3.7 3.4 untestable 25 µm 22-28 µm untestable untestable untestable untestable untestable untestable untestable (120 ° C × 10 MPa × 150 h, brake fluid plus 20% by weight water) Table 4 Peeling condition after immersion test, based on cross pattern (RR break number) primer Typical layer thickness 0.5 µm 2 µm 4 µm 7 µm 10 µm 14 µm 17 µm Typical layer thickness Layer thickness range <1 µm 1-3 µm 3-5 µm 6-8 µm 9-11 µm 13-15 µm 16-24 µm Top layer 2 µm 1-4 µm untestable untestable untestable untestable untestable untestable untestable 5 µm 4-6 µm untestable 100 100 100 100 50 untestable 8 µm 7-9 µm untestable 100 100 100 100 50 untestable 10 µm 9-11 µm untestable 100 100 100 100 50 untestable 15 µm 14-16 µm untestable 60 60 60 60 50 untestable 20 µm 19-21 µm untestable 60 60 60 60 50 untestable 25 µm 22-28 µm untestable untestable untestable untestable untestable untestable untestable (120 ° C × 10 MPa × 150 h, brake fluid plus 20% by weight water) Table 5 Rate of residual rubber peel strength after immersion test based on cross pattern (not immersed = 100) (Brake fluid plus 20% by weight water, 120 ° C × 10 MPa × 150 h) primer Typical layer thickness 0.5 µm 2 µm 4 µm 7 µm 10 µm 14 µm 17 µm Typical layer thickness Layer thickness range <1 µm 1-3 µm 3-5 µm 6-8 µm 9-11 µm 13-15 µm 16-24 µm Top layer 2 µm 1-4 µm untestable untestable untestable untestable untestable untestable untestable 5 µm 4-6 µm untestable 95 100 100 95 80 untestable 8 µm 7-9 µm untestable 90 100 100 100 55 untestable 10 µm 9-11 µm untestable 90 95 100 90 50 untestable 15 µm 14-16 µm untestable 50 70 65 70 50 untestable 20 µm 19-21 µm untestable 50 60 75 65 60 untestable 25 µm 22-28 µm untestable untestable untestable untestable untestable untestable untestable

In the immersion test, each sample was immersed in an immersion liquid consisting of polyethylene (brake fluid) and 20% by weight of water at 120 ° C and 10 MPa for 150 hours. In Table 4, RR break indicates the break of the rubber-rubber surface. It can be said that the adhesion between the metal element 21 and the elastic rubber element 23 the better the larger the fraction of the rubber-rubber surface is. Consequently, it can be said that the adhesion between the metal element 21 and the elastic rubber element 23 the better, the smaller the fraction at the interface between the metal element 21 and the first layer of adhesive 22a (or the lower the exposure of the metal element 21 in the break time).

If the thickness of the first layer of adhesive 22a (Primer) exceeds 15 µm, as shown in Table 2, it is difficult to apply the adhesive evenly. If the thickness of the adhesive layer 22a is less than 1 µm, on the other hand, the peel strength decreases so much that it becomes untestable as shown in Table 3, and the RR number decreases so much that it becomes untested as shown in Table 4. If the thickness of the adhesive layer 22a is less than 1 µm, the rate of the remaining rubber peel strength also decreases so much that it becomes untested, as shown in Table 5. Consequently, it is assumed that the first layer of adhesive 22a becomes brittle if the layer or layer thickness is less than 1 µm.

If the thickness of the second layer of adhesive 22b (Top layer) exceeds 21 µm, as shown in Table 2, it is difficult to apply the adhesive evenly. If the thickness of the adhesive layer 22b is less than 4 µm, on the other hand, the peel strength decreases so much that it becomes unstable as shown in Table 3, and the RR breakage decreases so much that it becomes unstable as shown in Table 4. If the thickness of the adhesive layer 22b is less than 4 µm, the rate of remaining peel strength also decreases, as shown in Table 5. Therefore, it is assumed that the second layer of adhesive 22b becomes brittle if the layer thickness is less than 4 µm.

The inventors found that the adhesive layer 22 of the pressure accumulator used in the braking device 1 has satisfactory adhesion when the rate of remaining peel strength is 32% or more. It was found that, as shown in Table 5, the first layer of adhesive 22a has excellent adhesion when its thickness is in the range of 1 µm to 15 µm. It was found that the second layer of adhesive 22b has excellent adhesion when its thickness is in the range of 4 µm to 21 µm.

Furthermore, it is believed that the adhesion between a metal and an organic adhesive strongly depends on the bonds formed between a hydroxyl group or carboxyl group on the surface of the metal and a polar group (hydroxyl group, carboxyl group, etc.) in the adhesive. Table 6 shows measurement results on the relationship between the hydroxyl group content in the first layer of adhesive 22a and peel strength after the immersion test. The hydroxyl group content was calculated from the content of a component containing the hydroxyl group by performing gas chromatography (GC.MS) analysis on a sample by drying the first adhesive layer shown in Table 6 under the following conditions 22a obtained on a stainless steel sheet at room temperature for 24 hours.

• GC: 5890 (HP),
• MS: 5971 (HP),
• Pyrolysator: PY-2010D (FRONTIER LAB), Trägergas: He, Messtemperatur:
• Pyrolysetemperatur: 100 °C bis 550 °C,
• CG: 50 °C bis 300 °C.

Tabelle 6 Beibehaltung der Abziehfestigkeit (%) nach Eintauchen (basierend auf der Festigkeit (100 %) ohne Eintauchen) (Bremsfluid zuzüglich 5 Gew.-% Wasser, 120 °C × 10,5 MPa × 300 h) Deckschicht (zweite Klebstofflage C0 C1 Hauptbestandteil: chlorinierter Polyethylen kautschuk Chlorgehalt: 15 Gew.-% oder mehr Sulfogruppengehalt: 2,0 Gew.-% oder mehr SP-Wert = 8,2-9,0 Hauptbestandteil: chlorinierter Polyethylenkautschuk Chlorgehalt: 11,0 Gew.-% oder weniger Sulfogruppengehalt: 1,0 Gew.-% oder weniger SP-Wert = 8,3-9,3 Grundierung (erste Klebstofflage) P0 Hydroxylgruppengehalt von 15 Gew.-% 40 63 P1 Hydroxylgruppengehalt von 14 Gew.-% 39 59 P2 Hydroxylgruppengehalt von 10 Gew.-% 34 55 P3 Hydroxylgruppengehalt von 8 Gew.-% 30 28 P4 Hydroxylgruppengehalt von 1 Gew.-% 10 nicht geprüft Devices used:

• GC: 5890 (HP),
• MS: 5971 (HP),
• Pyrolyser: PY-2010D (FRONTIER LAB), carrier gas: He, measuring temperature:
• Pyrolysis temperature: 100 ° C to 550 ° C,
• CG: 50 ° C to 300 ° C.

Table 6 Retention of peel strength (%) after immersion (based on strength (100%) without immersion) (Brake fluid plus 5% by weight water, 120 ° C × 10.5 MPa × 300 h) Top layer (second layer of adhesive C0 C1 Main ingredient: chlorinated polyethylene rubber Chlorine content: 15% by weight or more Sulfo group content: 2.0% by weight or more SP value = 8.2-9.0 Main ingredient: chlorinated polyethylene rubber Chlorine content: 11.0% by weight or less Sulfo group content: 1.0% by weight or less SP value = 8.3-9.3 Primer (first layer of adhesive) P0 Hydroxyl group content of 15% by weight 40 63 P1 Hydroxyl group content of 14% by weight 39 59 P2 Hydroxyl group content of 10% by weight 34 55 P3 Hydroxyl group content of 8% by weight 30th 28 P4 Hydroxyl group content of 1% by weight 10th Not checked

The hydroxyl group content in the first layer of adhesive 22a serves as an index for the number of between the first layer of adhesive 22a and the metal element 21 hydrogen bonds formed. It has been demonstrated that satisfactory peel strength can be maintained even after the immersion test if the weight fraction of the hydroxyl group in the first layer of adhesive 22a Is 10% or more as shown in Table 6. The measurement results of Table 6 also indicate that the retention rate of C1, which mainly consists of chlorinated EPDM, is higher than that of C0, which mainly consists of chlorinated polyethylene rubber. Furthermore, the measurement results indicate that better peel strength can be maintained when chlorinated EPDM for the second layer of adhesive 22b is selected such that the proportions by weight of chlorine and the sulfo group therein are 11.0% or less and 1.0% or less, respectively. These results are in line with those in 6 shown measurement results.

The first layer of adhesive is based on these results 22a for example, a phenolic resin layer is preferred. Preferably, their thickness should range from 1 µm to 15 µm be set. The reason for this is that the phenolic resin layer cannot easily spread evenly if its thickness exceeds 15 µm. If the phenolic resin layer is brittle with a thickness of more than 15 µm, it breaks easily if the pressure accumulator 1 is subjected to a mechanical force from the braking device. The sealing element 6 can therefore hardly maintain its sealing performance for a long time.

On the other hand, as a second layer of adhesive 22b a chlorinated EPDM (ethylene-propylene-diene-methylene copolymer) resin layer is preferred. Their thickness should preferably be set in the range from 4 μm to 21 μm. The reason for this is that the layer of chlorinated EPDM cannot easily spread evenly if its thickness is less than 4 µm and because it is brittle if its thickness exceeds 21 µm. If layer made of chlorinated EPDM with a thickness of more than 21 µm is fragile, it breaks easily if the pressure accumulator 1 is subjected to a mechanical force from the braking device. The sealing element 6 can therefore hardly maintain its sealing performance for a long time.

Thus, the adhesive layer has 22 a double-layer structure that the first layer of adhesive 22a , which is formed from the phenolic resin layer with a thickness of 1 µm to 15 µm, and the second adhesive layer 22b , which is formed from the layer of chlorinated EPDM with a thickness of 4 µm to 21 µm. Furthermore, the weight percentages of chlorine and the sulfo group in the adhesive layers are 11.0% or less and 1.0% or less, respectively, with the hydroxyl group content in the first adhesive layer 22a is set to 10% by weight or more. If the sealing element 6 is immersed in the brake fluid, the peel strength between the metal element 21 and the elastic rubber member can be maintained satisfactorily for a long time. Consequently, the sealing element has 6 according to the accumulator 1 good sealing performance in the long term in the present embodiment.

The following is a description of the elastic rubber member 23 . Preferably the rubber element 23 be made of elastic rubber with a hardness of SHORE A 80 specified by JIS K6253 and a tensile strength of at least 20 MPa. In the present embodiment, for the rubber member 23 elastic rubber with the properties shown in Table 7 is used. Table 7 Physical Properties State of the art Embodiment Test conditions original state Hardness [SHORE A] 80 89 JIS K 6253 Confidence [MPa] 13.0 22.8 JIS K 6251 stretching speed: 500 mm / min. Strain [%] 100 160 Resistance to thermal aging Hardness change [Pts] tensile strength change rate [%] +3 ± 0 JIS K 6257 120 ° C × 72 h, in air ± 3 +6 Strain Change Rate [%] ± 0 ± 0 Resistance to brake fluid (5 vol.% Water) Change in hardness [Pts] -10 -4 JIS K 6258 brake fluid 120 ° C × 72h Tensile strength change rate [%] -11 -3 Strain Change Rate [%] +2 ± 0 Volume change rate [%] +3.0 +3.0

Table 7 shows properties of the elastic rubber member 23 of the sealing element 6 according to the present embodiment compared to that of elastic rubber constituting a conventional sealing member as a comparative example. When using the elastic rubber element of the sealing element, which is formed from the elastic rubber of the comparative example, the sealing performance of the pressure accumulator is reduced 1 lost earlier when it is repeatedly stressed in a brake fluid of 100 ° C or more at 21 MPa and 0 MPa. In the case of the sealing element 6 which is the elastic rubber element 23 used in the present embodiment, on the other hand, it has been demonstrated that long-term satisfactory sealing performance can be ensured.

When the pressure in the liquid chamber 12th falls below a given level is between the metal element 21 and the elastic rubber element 23 applied a shear stress of about 0.5. The highest shear stress is applied to an area near the root of the protrusion 6a exercised, their strength is about 0.7.

The sealing member, the elastic rubber member of which was formed from the elastic rubber of the comparative example, broke when subjected to mechanical force (repeated stress of 0.5 (maximum 0.7)) in a brake fluid of 100 ° C. On the other hand, it was demonstrated that the sealing element 6 which is the elastic rubber element 23 used in the present embodiment did not break when subjected to mechanical force (repeated stress of 0.5 (maximum 0.7)) in a brake fluid of 100 ° C.

Furthermore, the sealing elements 6 using materials A to E with different tensile strengths and rubber hardness as an elastic rubber element 23 manufactured. The correlations between tensile strength, rubber hardness and the breaking frequency of loading were measured by performing tests on the sealing elements 6 have been repeatedly stressed in a brake fluid of 100 ° C or more at 21 MPa and 0 MPa. The table shows the results of the measurement. Table 8 material Tensile strength [MPa] Rubber hardness (JIS A) Breaking frequency of loading (1,000 or less omitted) A 13.0 81 6,000 B 18.8 82 8,000 C. 20.4 78 15,000 D 20.5 82 35,000 or more E 22.8 89 35,000 or more

As shown in Table 8, it was demonstrated that a satisfactory sealing performance could be ensured in the long term if one of the materials with a tensile strength of at least 20 MPa and a rubber hardness of at least 80 for the elastic rubber element 23 has been used.

The following is a description of the metal element 21 . The metal element body 21a can be formed from a weldable steel material such as SPCC. The surface of the weldable steel quickly corrodes under the influence of water and the like. If the surface of the metal element body 21a is corroded, the metal element deteriorates 21 through oxidation and leaves the adhesive function between the metal element 21 and the elastic rubber element 23 to. Preferably, the metal element body 21a therefore with the protective layer 21b made of a phosphate layer, e.g. B. a zinc calcium phosphate layer is formed, coated. The zinc calcium phosphate layer should be more preferred if it is used as a protective layer 21b is used, have a crystal grain size of at most 8 microns. If the crystal grain size of the zinc calcium phosphate exceeds 8 µm, cracks quickly form between crystals. The zinc-calcium phosphate layer thus becomes brittle, which is why the sealing performance of the sealing element 6 is difficult to ensure for a long time. Table 9 shows the relationship between the crystal grain size of calcium phosphate and the adhesiveness. Table 9 Zinc calcium phosphate crystal grain size [µm] (average diameter) 2-6 4-8 8-12 Peel strength of cross pattern [MPa] Early stage 5.7 5.8 5.6 After immersion test (brake fluid plus 5% by weight water, 120 ° C × 10 MPa × 150 h) 5.4 5.6 5.7 Layer subtraction (RR fraction) 95% or more 95% or more RR 60% MC 40% (MC: near the primed surface)

As shown in Table 9, the sheet peeling strength was found to decrease so that at the interface between the metal member body 21a and the first layer of adhesive 22a peeling was brought about if for the protective layer 21b Zinc calcium phosphate with a grain size of more than 8 µm was used. On the other hand, it was found that the use of zinc calcium phosphate with a grain size of more than 8 microns for the protective layer 21b has been used. On the other hand, it was found that the use of zinc calcium phosphate with a grain size of at most 8 µm for the protective layer 21b can maintain satisfactory peel strength despite using a large displacement deformation mode such as ply peel strength.

The protective layer 21b is not limited to a phosphate layer such as the zinc-calcium phosphate layer, but may alternatively be a layer formed by plating or chromite treatment. With this arrangement, the protective layer 21b also corrosion of the metal element body 21a prevent.

Furthermore, the inventors have found that with a corroded metal element body 21a possibly water or the like between the metal element 21 and the elastic rubber element 23 penetrates and thereby reduces the peel strength. According to the present embodiment, the metal element body can be prevented 21a corroded so that the peel strength between the metal element 21 and the rubber element 23 can be maintained satisfactorily for a long time. Thus, the sealing element has 6 excellent sealing performance in the long term.

7 shows the relationship between the immersion time of the sealing member 6 and the peel strength between the metal member 21 and the elastic rubber element 23 . In 7 represent the curves X and Y measurement results obtained when using samples X and Y, respectively.

• Probe X (Dichtungselement 6 der vorliegenden Erfindung): Dichtungselement mit dem Metallelement 21, das aus einem Blech aus schweißbarem Stahl gebildet war, das eine Zink-Kalziumphosphatschicht, bei die Kristallkorngröße 8 µm oder weniger betrug, enthielt (wobei die anderen Bedingungen wie bei dem Dichtungselement 6 der vorliegenden Ausführungsform waren),
• Probe Y (Vergleichsbeispiel): Dichtungselement mit dem Metallelement 21, das aus einem Blech aus schweißbarem Stahl gebildet war, das eine zerschossene Oberfläche aufwies (wobei die anderen Bedingungen wie bei dem Dichtungselement 6 der vorliegenden Ausführungsform waren),
• Tauchflüssigkeit: Bremsfluid, das 5 Vol.-% Wasser enthielt,
• Bremsfluidtemperatur: 120 °C,
• Druck mit dem das Dichtungselement 6 beaufschlagt wurde (gleich dem Differenzdruck zwischen der Gas- und der Flüssigkeitskammer): 10,2 MPa,
• Abziehfestigkeits-Messverfahren: Das gleiche wie oben.

The test was carried out under the following conditions.

• Sample X (sealing element 6 of the present invention): Sealing element with the metal element 21 formed of a weldable steel sheet containing a zinc-calcium phosphate layer whose crystal grain size was 8 µm or less (the other conditions being the same as the sealing member 6 the present embodiment),
• Sample Y (comparative example): sealing element with the metal element 21 , which was formed from a sheet of weldable steel that had a shattered surface (the other conditions being the same as the sealing member 6 the present embodiment),
• Immersion fluid: brake fluid containing 5 vol.% Water,
• Brake fluid temperature: 120 ° C,
• Pressure with which the sealing element 6 was applied (equal to the differential pressure between the gas and the liquid chamber): 10.2 MPa,
• Peel strength measurement method: The same as above.

When the immersion time was about 200 hours, the difference in peel strength between samples X and Y was small. When the immersion time was extended to about 300 hours, the peel strength of Sample Y decreased to about 3 MPa. On the other hand, the peel strength of Sample X was found to be a satisfactory level of about 4 MPa.

Consequently, as a protective layer 21b a zinc-calcium phosphate layer with a grain size of at most 8 µm is used. If the sealing element 6 is immersed in the brake fluid, in this case the peel strength between the metal element 21 and the elastic rubber element 23 be satisfactorily maintained for a long time, so that the sealing element 6 has excellent sealing performance in the long term.

If the differential pressure between the gas chamber 11 and the liquid chamber 12th increases, can according to the pressure accumulator described above 1 In the present embodiment, the brake fluid (support oil) between the bellows 3rd and the partition 5 stay trapped. As a result, there is no possibility that an undue force is exerted on the bellows 3rd acts.

In addition, the sealing element 6 ensure its sealing performance even at high temperature (of 120 ° C or more) and under high pressure (of 10 MPa or more) for a long time. Thus, when the sealing member is attached to the brake device or other hydraulic pressure device subjected to such a high temperature and pressure, it can maintain the sealing performance in the long term.

Because the sealing performance of the sealing element 6 can be ensured in the long term, the bellows, if it has a relatively low pressure resistance, can also be used as a membrane.

According to the accumulator 1 for use as the vehicle brake system component of the present invention, the sealing performance can thus be ensured in the long term.

According to the present embodiment, it has also been described that the pressure accumulator 1 is applied to the braking device. However, the accumulator is 1 of the present embodiment is not limited to the brake fluid, but can be applied generally to various hydraulic fluids such as general-purpose oil, motor gasoline, light oil, etc., without lacking satisfactory durability for a long time. There is therefore no need for a complex operation, such as changing the material of the sealing element 6 depending on the type of liquid. In addition, the manufacturing cost can be reduced because no different materials corresponding to different oils have to be provided.

Although the sealing element 6 according to the present embodiment on the cap portion 4th attached, it just needs to be designed so that it connects to the circulation 15 can close in a liquid-impermeable manner if the bellows 3rd expands or contracts by the given stroke. So the sealing element 6 for example on the partition 5 (End wall 5a) be provided.

With regard to the 8th to 10th a second embodiment of the present invention will now be described. In connection with the present embodiment, a master cylinder is described as an example of the vehicle brake system component. A master cylinder 31 of the present embodiment is except for the structure of a center valve 34 constructed in the same way as today's master cylinder.

As in 8th is shown is the master cylinder 31 a device that converts an operating force applied to an input mechanism via a brake pedal or the like into a fluid pressure. It encompasses a body 32 , a pole 33 , the middle valve 32 for use as a fluid pressure generating mechanism, a piston 35 etc. in the body 32 are the rod 33 , the valve 34 and the piston 35 arranged in the order mentioned. The pole 33 points to the side of the valve 34 a forehead section 33a on. The valve 34 is a sealable composite component that also serves as a sealing element. The middle valve 34 contains a metal element 21 , an adhesive layer 22 and an elastic rubber element 23 and is in the same way as the sealing element 6 of the first embodiment (see 9 and 10th ).

In 8th denotes the reference symbol 38 a coil spring for use as a pressure or restraint. The pole 33 and the piston 35 are by the coil spring 38 forced in a direction in which they move apart. The piston 35 moves forward towards the bar 33 when the brake is applied. Furthermore, in the body 32 a liquid chamber 36 and an outlet port 37 intended. If the brake is not applied, the fluid chamber is stationary 36 via the middle valve 34 with the outlet connection 37 in connection (see 9 ).

The master cylinder 3rd works in the following way. When the brake is applied, the piston moves forward toward the rod 33 . If the piston 35 Moving forward, the middle valve hits 34 against the forehead section 33a the rod 33 , causing the outlet port 37 is closed (see 10th ). As a result, the liquid chamber 36 from the connection 37 separated so that in the chamber 36 a fluid pressure is generated. When the brake is released, the rod 33 and the middle valve 34 open. Thus the liquid chamber is standing 36 and the outlet port 37 in connection with each other, whereupon the chamber 36 is decompressed.

According to the master cylinder 31 for use as the vehicle brake system component of the present embodiment is the center valve 34 in the same way as the sealing element 6 of the pressure accumulator 1 constructed as a vehicle brake system component of the first embodiment, so that the sealing performance can be ensured in the long term.

With regard to the 11 to 12th a third embodiment of the present invention will now be described. In connection with the present embodiment, a plunger pump is described as an example of the vehicle brake system component. A plunger pump 41 the present embodiment is except for the structure of a sealing member 44 constructed in the same way as today's plunger pumps.

As in 11 shown includes the plunger pump 41 a body 42 , a wave 43 , the sealing element 44 etc. The wave 43 is in the body 42 arranged. Furthermore, in the body 42 a pump head 45 Are defined. With the plunger pump used as a brake system component 41 serves the scooping room 45 at the same time as a cam chamber. The ring-shaped sealing element 44 separates a brake fluid from the scoop 45 . The sealing element 44 is along the outer circumference of the shaft 43 arranged. The sealing element 44 is also a sealable composite component. It contains a metal element 21 , an adhesive layer 22 and an elastic rubber element 23 and is in the same way as the sealing element 6 constructed in the first embodiment (see 12th ).

According to the plunger pump 41 for use as the vehicle brake system component of the present embodiment is the sealing member 44 in the same way as the sealing element 6 of the pressure accumulator 1 constructed as a vehicle brake system component of the first embodiment, so that the sealing performance can be ensured in the long term.

The present invention is not limited to the application to the accumulator, the master cylinder and the plunger pump, but can be applied very differently to any other vehicle brake system components.

Additional benefits and modifications will quickly become apparent to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described here. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims or their equivalents.

Claims (21)

Vehicle brake system component (1) such as a pressure accumulator used in a brake system of a vehicle, the vehicle brake system component (1) comprising: a pressure vessel (2) with a gas chamber (11), in which a gas is enclosed, and a liquid chamber ( 12) which is filled with a liquid; a membrane (3) which has a fixed end (3a) attached to the pressure vessel (2) and a free end (3b) which can expand and contract in the direction of an axis (L) of the pressure vessel (2) and in the pressure vessel (2) is arranged to separate the gas chamber (11) and the liquid chamber (12); a partition (5) which is arranged in the liquid chamber (12) and has a circulation connection (15) through which the liquid flows into the liquid chamber (12) and out of the liquid chamber (12) when the membrane (3) expands or contracting; and a sealing element (6) which closes the circulation connection (15) in a liquid-impermeable manner in order to enclose the liquid between the partition wall (5) and the membrane (3) when the membrane (3) expands and contracts by a given stroke, wherein the sealing element (6) comprises a metal element (21), an adhesive layer (22) provided on the metal element (21), which is assigned to at least a part of the surface of the metal element (21), and an elastic rubber element connected to the metal element (21) (23), with the adhesive layer (22) in between, characterized in that the adhesive layer (22) has a first adhesive layer (22a) in contact with the metal element (21) and a second adhesive layer (22b), which is provided on the first layer of adhesive (22a), the first layer of adhesive (22a) and the second layer of adhesive (22b) being set such that the proportions by weight of chlorine and a sulfo group therein not more than 11.0% or not more than 1.0%. Vehicle brake system component (1) Claim 1 , characterized in that the metal element (21) has a metal element body (21a) and a protective layer (21b) which is provided on the surface of the metal element body (21a) and prevents a drop in quality of the metal element body (21a). Vehicle brake system component (1) Claim 2 , characterized in that the protective layer (21b) is a zinc-calcium phosphate layer with a crystal grain size of at most 8 µm. Vehicle brake system component (1) Claim 1 , characterized in that the metal element (21) and the elastic rubber element (23) are connected to one another by vulcanization bonding using the adhesive layer (22). Vehicle brake system component (1) Claim 1 , characterized in that the first layer of adhesive (22a) is fixed so that the weight fraction of a hydroxyl group therein is at least 10%. Vehicle brake system component (1) Claim 1 , characterized in that the thickness of the first layer of adhesive (22a) is in the range from 1 µm to 15 µm, while the thickness of the second layer of adhesive (22b) is in the range from 4 µm to 21 µm. Vehicle brake system component (1) Claim 1 , characterized in that the first adhesive layer (22a) is a phenolic resin layer, while the second adhesive layer (22b) is a chlorinated EPDM resin layer. Vehicle brake system component (1) Claim 6 , characterized in that the first adhesive layer (22a) is a phenolic resin layer, while the second adhesive layer (22b) is a chlorinated EPDM resin layer. Vehicle brake system component (1) after a Claims 1 to 8th , characterized in that the elastic rubber member (23) is made of elastic rubber having a hardness greater than SHORE A 80 specified by JIS (Japanese Industry Standard) K6253 and a tensile strength of at least 20 MPa. Vehicle braking system component (1, 31, 41) used in a braking system of a vehicle, characterized in that it comprises a sealable composite component (6, 34, 44) containing a metal element (21) and an elastic rubber element (23) connected together and arranged so that they are in contact with a brake fluid. Vehicle brake system component (1, 31, 41) according to Claim 10 , characterized in that the composite component (6, 34, 44) the metal element (21), an adhesive layer (22) provided on the metal element (21), which is assigned to at least part of the surface of the metal element (21), and with contains the elastic element (23) connected to the metal element (21), the adhesive layer (22) being located between them. Vehicle brake system component (1, 31, 41) according to Claim 11 , characterized in that the metal element (21) has a metal element body (21a) and a protective layer (21b) which is provided on the surface of the metal element body (21a) and prevents a drop in quality of the metal element body (21a). Vehicle brake system component (1, 31, 41) according to Claim 11 , characterized in that the protective layer (21b) is a zinc-calcium phosphate layer with a crystal grain size of at most 8 µm. Vehicle brake system component (1, 31, 41) according to Claim 11 , characterized in that the metal element (21) and the elastic rubber element (23) are connected to one another by vulcanization bonding using the adhesive layer (22). Vehicle brake system component (1, 31, 41) according to Claim 11 characterized in that the adhesive layer (22) includes a first adhesive layer (22a) in contact with the metal member (21) and a second adhesive layer (22b) provided on the first adhesive layer (22a). Vehicle brake system component (1, 31, 41) according to Claim 15 , characterized in that the first layer of adhesive (22a) is fixed so that the weight fraction of a hydroxyl group therein is at least 10%. Vehicle brake system component (1, 31, 41) according to Claim 15 , characterized in that the first layer of adhesive (22a) and the second layer of adhesive (22b) are fixed such that the weight fractions of chlorine and a sulfo group therein are at most 11.0% and at most 1.0%. Vehicle brake system component (1, 31, 41) according to Claim 15 , characterized in that the thickness of the first layer of adhesive (22a) is in the range from 1 µm to 15 µm, while the thickness of the second layer of adhesive (22b) is in the range from 4 µm to 21 µm. Vehicle brake system component (1, 31, 41) according to Claim 15 , characterized in that the first adhesive layer (22a) is a phenolic resin layer, while the second adhesive layer (22b) is a chlorinated EPDM resin layer. Vehicle brake system component (1, 31, 41) according to Claim 18 , characterized in that the first adhesive layer (22a) is a phenolic resin layer, while the second adhesive layer (22b) is a chlorinated EPDM resin layer. Vehicle brake system component (1, 31, 41) according to one Claims 10 to 20 , characterized in that the elastic rubber member (23) is made of elastic rubber having a hardness greater than SHORE A 80 specified by JIS (Japanese Industry Standard) K6253 and a tensile strength of at least 20 MPa.

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