WO2019185369A1 - Pressurised container and method for producing an outer casing for a pressurised container - Google Patents

Abstract

The invention relates to a pressurised container (10) and to a method for producing an outer casing (12) for a pressurised container (10) of this type. The pressurised container (10) comprises an outer casing (12), which has a cylinder-like central region (10) and two end regions (16, 18) attached thereto, a hollow-cylindrical extension (20) being formed in each case at both axial ends of the cylinder-like central region (14) of the outer casing (12), which extension projects beyond the respective end region (16, 18). According to the invention, each hollow-cylindrical extension (20) transitions at the open end thereof into a plurality of fastening elements (36), each of which has a planar connection face (38) arranged radially externally.

Description

 Pressure vessel and method for producing an outer shell for a

 pressure vessel

DESCRIPTION:

The invention relates to a pressure vessel according to the preamble of patent claim 1. Furthermore, the invention relates to a method for producing an outer shell for such a pressure vessel. Pressure vessels and corresponding methods for producing an outer shell for such a pressure vessel are known in numerous variations. In general, such pressure vessels can be filled, for example, with gases or pressure-liquefied gases and therefore store a considerable amount of energy. Thus, for example, a so-called type 4 high-pressure container for compressed natural gas can be installed in a rear-side loading space and / or below ground in the area of a center tunnel of the vehicle body of a vehicle which is operated with natural gas.

A frequently used method for fastening pressure vessels in the vehicle or under the vehicle uses tank straps, which allow a tolerance compensation when filling the container, but do not offer a structural influence of the container stiffness on the body of the vehicle. In addition, a deflection of the pressure tank is ensured in plastic deformation of the body, for example in a side crash, which is to ensure protection against damage to the pressure tank. Thus, the transmission of the crash energy takes place solely by the components or load paths of the body. A generic pressure vessel preferably has a cylindrical construction, in which a cylindrical pressure vessel jacket is closed on both sides by bulged, outwardly curved bottoms. The pressure vessel wall can be constructed, for example, in three layers and comprise an inner layer, a middle layer of a fiber composite plastic and an outer layer of a further fiber composite plastic. In the above-mentioned type 4 high pressure vessel, the inner layer is a plastic liner made by blow molding or rotary / sintering process or thermoforming process. The plastic liner reinforcing middle layer is preferably wound in a wet winding process as a fiber winding on the plastic liner. Specifically, the fiber winding consists of, for example, carbon, aramid, glass and / or boron fibers embedded in a matrix of thermosets or thermoplasts. The fibers are applied to the plastic liner in different fiber orientations. The preferably impact-absorbing outer layer may likewise be a fiber winding which is wound onto the middle layer in a wet winding process. The outer winding thus formed consists, for example, of carbon and / or glass fibers embedded in a matrix.

The finished high pressure container has, for example, on a stirnsei term container bottom on an outwardly projecting neck piece, in which a valve is integrated. Otherwise, the high-pressure vessel is usually completely smooth on the outside. In its installed position, the high-pressure container is positionally secured in position by means of tension bands, which surround the smooth surface Zylin derwand the high-pressure vessel.

From DE 10 2015 206 826 A1 a pressure vessel for a motor vehicle, with a fastening device is known. The fastening device is designed to connect the pressure vessel with a body of the motor vehicle. The fastening device comprises at least two connecting pins and at least two bearings. In each case a connecting pin is connected to a bearing in a connection point. The connecting pins and / or the bearings are each connected to the pressure vessel in a pressure tank connection area and extend from the outer surface away from the pressure vessel. The pressure tank connection areas each have an extension. The connecting pin and the bearing are formed and arranged in the connection point at least in regions such that the extension E is guided kinematically by a movement of the bearing and / or the connecting pin with only one translational degree of freedom.

From DE 10 2015 007 047 B4 a process for producing a pressurizable container is known, which has a made of a fiber-plastic composite, cylindrical central part, at the ends of each of which a bottom part of a fiber-reinforced plastic composite material is made to close the container. In this case, the middle part of the container is arranged on a winding mandrel of a wound body as a prefabricated middle part or produced by winding up a roving. An inner surface of the bottom part is defined by the winding mandrel of the winding body and an end of the central part adjacent to the bottom part, and an outer surface of the bottom part is defined by a plurality of shaping parts. The bottom part of the container is produced by winding a preferably unidirectional roving into a winding space defined by the winding mandrel and the shaping parts up to the end of the middle part, the shaping parts starting successively from a winding axis of the winding body be arranged on the outside of the winding axis when a part winding space formed between the winding mandrel and the respective previously arranged shaping part is filled.

The object of the present invention is to provide a pressure vessel and a method for producing an outer shell for such a pressure vessel, which can be integrated into the body structure in a simple manner as a stiffening element.

This object is achieved by a pressure vessel having the features of patent claim 1 and by a method for producing an outer shell for a pressure vessel having the features of patent claim 11. Before some embodiments with expedient developments of the invention are specified in the dependent claims. In order to provide a pressure vessel and a method for producing an outer shell for such a pressure vessel, which can be integrated in a simple manner as stiffening element in the body structure, a hollow cylindrical extension is formed at both axial ends of a cylinder-like central region of an outer shell, which over the projects beyond the respective end region and merges at its open end into a plurality of fastening elements which each have a plane connection surface arranged radially on the outside.

The method for producing an outer shell for such a pressure vessel comprises the steps of: wrapping an inner container and / or a respective winding mandrel adjoining axially thereto with a continuous fiber material, so that at both axial ends of the cylinder-like middle region of the outer shell hollow cylindrical extension is formed, which projects beyond the respective end region. Curing of the outer shell and mechanical processing of the respective extension take place in such a way that the fastening elements with the respective planar connection surfaces are formed therefrom. Here, the wound continuous fiber material can be provided with a matrix material before curing. Alternatively, the continuous fibers may already be preimpregnated with the matrix system.

In an advantageous embodiment of the pressure vessel, the fastening elements can be designed as tabs. In this case, the tabs may each have an opening through which a screw can be guided in order to screw the pressure vessel to the body structure.

In a further advantageous embodiment of the pressure vessel, the fastening elements can be introduced into the hollow cylindrical extension by a first machining operation, in particular by milling or cutting. The planar connection surfaces can then be introduced into the fastening elements by a second machining operation, in particular by milling. In a further advantageous embodiment of the pressure vessel, at least the hollow cylindrical extension of the outer shell may have a round outer contour and a polygonal inner contour with flat inner surfaces and / or round inner surfaces. In addition, the planar connection surfaces can be formed in the region of the pla nen inner surfaces. As a result, any number of connection surfaces in different angular positions can be realized. The connection areas can thus be freely positioned within the axis of rotation and designed independently of the vehicle.

In a further advantageous embodiment of the pressure vessel, the outer shell can be made of a fiber-reinforced, preferably a continuous fiber reinforced plastic. In addition, at least in the region of the fastening elements, the outer shell can have a jacket structure with a radially inner laminate layer and a radially outer laminate layer. In this case, the laminate layers can have different fiber materials, wherein the radially inner laminate layer can remain undamaged when the planar connection surfaces are formed. The fiber composite plastic, for example, a carbon fiber reinforced, preferably a continuous carbon fiber reinforced plastic (CFRP), or a glass fiber reinforced, preferably an endless glass fiber reinforced plastic (GRP) be. In the production of the outer shell, various fiber materials may be used depending on the desired requirements such as stiffness, strength, impact detection, etc. In this case, for example, the layers of the inner laminate layer made of carbon fibers, the layers of the outer laminate layer of glass fibers can be produced. Due to the superficial damage of the outer laminate layer for the representation of the planar bonding surfaces in the milling process, only the glass fibers but not the carbon fibers of the inner laminar layer are released. Therefore, the structural properties of the carbon fiber matrix composite are maintained, and corrosive interactions with metallic components in the area of connection of the body structure of the vehicle can be avoided.

In a further advantageous embodiment of the pressure vessel, the outer shell may be a fluid-tight inner container made of metal or fiber-reinforced Surround plastic or unreinforced plastic surface or form the fluid-tight inner container itself.

In an advantageous embodiment of the method for producing an outer shell for such a pressure vessel, the respective winding mandrel may have a polygonal cross-section adapted at least in the region of the fastening elements to be formed, and a polygonal cross-section adapted to the planar surfaces to be formed. This results in different radii in the areas of the round inner surfaces and the areas of the flat inner surfaces for the inner contour of the shell structure of the outer shell. As a result, the thread tension in the winding process is unequal, which is why detachment of the thread from the tool core can occur in areas with higher radii. Due to the constant radius of the outer contour of the shell structure of the outer shell, a higher wall thickness and thus a partially lower fiber volume content are formed in these areas.

The features and feature combinations mentioned above in the description, as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respectively indicated combination but also in other combinations or alone, without departing from the scope of the invention. Thus, embodiments are also included and disclosed by the invention, which are not explicitly shown or explained in the figures, but which emerge and can be generated by separated combinations of features from the embodiments explained.

An embodiment of the invention is illustrated in the drawing and will be explained in more detail in the following description. In the drawing, like reference numerals denote components or elements that perform the same or analog functions. Hereby show:

1 shows a schematic perspective view of an inner container for a pressure vessel according to the invention; FIG. 2 is a schematic perspective view of the inner container of FIG. 1 wrapped in an outer sheath in front of a mechanical machining; FIG. 3 is a schematic sectional view of the outer shell in the region of a hollow cylindrical extension,

4 shows an illustration of a detail IV from FIG. 3; FIG. 5 shows a schematic perspective view of an embodiment of a pressure vessel according to the invention; and

6 shows an illustration of a detail VI from FIG. 6. As can be seen from FIGS. 1 to 6, the exemplary embodiment of a pressure vessel 10 according to the invention comprises an outer shell 12, which has a cylinder-like central area 14 and two adjoining it. ßende end portions 16, 18 has. At both axial ends of the cylinder-like middle region 14 of the outer shell 12, a hollow cylindrical extension 20 is formed, which projects beyond the respective end region 16, 18.

According to the invention, the respective hollow-cylindrical extension 20 merges at its open end into a plurality of fastening elements 36, which each have a plane connection surface 38 arranged radially on the outside.

As is further apparent from FIGS. 2 and 5, the outer shell 12 encloses the fluid-tight inner container 11 in the illustrated embodiment in a planar manner. The fluid-tight inner container 11 can be produced, for example, from metal or from fiber-reinforced plastic (CFRP, GFRP) or from unreinforced plastic. Alternatively, the outer shell 12 itself can form the fluid-tight inner container 11. The outer shell 12 is made of a fiber-reinforced, preferably a continuous fiber reinforced plastic (CFRP, GFRP), which, for example, a carbon fiber reinforced, preferably a continuous carbon fiber reinforced plastic (CFRP) and / or a glass fiber reinforced, preferably an endless glass fiber reinforced plastic (GRP) is.

According to the method for producing an outer shell 12 for a pressure vessel 10, the inner container 1 1 shown in FIG. 1 and winding mandrels, not shown at both ends, are wound with an endless fiber material, so that at both axial ends 16, 18 a cylindrical projection 20 is formed in each case of the cylin-like central region 14 of the outer shell 12, which protrudes beyond the respective end region 16, 18, as can be seen further from FIG. 2. Subsequently, the wound continuous fiber material is provided with a matrix material. Alternatively, the continuous fibers may already be preimpregnated with the matrix system. Subsequently, the outer shell 12 hardens. In the illustrated exemplary embodiment, the respective winding mandrel has, at least in the region of the fastening elements 36 to be formed, a polygonal cross section adapted to the contact surfaces 38 to be formed.

As is further apparent from FIGS. 3 and 4, at least the hollow cylindrical extensions 20 of the outer shell 12 have a round outer contour 24 and a polygonal inner contour 22 with flat inner surfaces 26 and round inner surfaces 28. As can also be seen from FIGS. 3 and 4, the inner contour 22 is designed with sixteen corners with eight planar and eight round alternating inner surfaces 26, 28. In the angular regions of the planar inner surfaces 26, the winding radius of the inner contour 22 is significantly greater than at the circular inner surfaces 28 of the inner contour. As a result, the thread tension in the winding process is unequal, which is why, in the areas with higher radii, detachment of the thread from the tool core can occur. Due to the constant radius of the outer contour 24 of the shell structure 30 of the outer shell 12, a higher wall thickness and thus a partially lower fiber volume content are formed in these regions.

As can also be seen in particular from FIGS. 3 and 4, the outer shell 12, at least in the region of the fastening elements 36, has a jacket structure 30 with a radially inner laminate layer 32 and a radially outer one Laminate layer 34 on. Various fiber materials can be used according to the desired requirements, such as stiffness, strength, impact detection, etc., to generate the cladding structure 30. In the illustrated embodiment, the inner laminate layer 32 is made of carbon fiber layers, and the outer laminate layer 34 is made of fiberglass layers.

After curing of the outer shell 12, the extensions 20 are machined in accordance with the invention in such a way that the fastening elements 36 with the respective planar connection surfaces 38 are formed therefrom. In this case, the fastening elements 36 are introduced into the respective hollow-cylindrical extension 20 by a first machining, for example by milling or cutting. Subsequently, the planar connection surfaces 38 are introduced into the fastening elements 36 by a second machining operation, for example by milling. As can also be seen from FIGS. 5 and 6, in the exemplary embodiment illustrated, the fastening elements 36 are designed as tabs 36A, which each have a fastening opening. Through the mounting holes screws can be performed to screw the pressure vessel 10 with a body structure, not shown, of a vehicle.

In addition, the planar attachment surfaces 38 are formed in the region of the planar inner surfaces 26. Furthermore, the radially inner laminate layer 32 remains undamaged when the planar connection surfaces 38 are formed. Thus, only the glass fibers of the outer laminate layer 34 but not the carbon fibers of the inner laminate layer 32 are released by the surface damage of the outer laminate layer 34 to depict the planar bonding surfaces 38 in the milling process. Therefore, the structural properties of the carbon fiber matrix composite of the inner laminate layer 32 are advantageously maintained. In addition, corrosive interactions are avoided to Metalli's components in the connection area of the body structure of the vehicle in an advantageous manner. LIST OF REFERENCE NUMBERS

10 pressure vessels

 1 1 inner container

12 outer shell

 14 mid-range

 16, 18 end area

20 extension

22 inner contour

24 outer contour

 26 plane inner surface

28 round inner surface

30 sheath structure

32 inner laminate layer

34 outer laminate layer

 36 fastener

 36A tab

 38 connection area

io

Claims

 CLAIMS: A pressure vessel (10) having an outer shell (12) which has a cylinder-like central region (14) and two adjoining end regions (16, 18), wherein at both axial ends of the cylinder-like central region (14) of the outer shell (12) respectively a hollow cylindrical extension (20) is formed which projects beyond the respective end region (16, 18), characterized, that the respective hollow-cylindrical extension (20) merges at its open end into a plurality of fastening elements (36), each of which has a radially outer plane connection surface (38). Pressure vessel (10) according to claim 1, characterized in that the fasteners (36) are designed as tabs (36A). Pressure vessel (10) according to claim 1 or 2, characterized in that the fastening elements (36) are introduced into the corresponding hollow-cylindrical extension (20) by a first machining operation, wherein the planar connection surfaces (38) are introduced into the fastening elements (36) by a second machining operation. Pressure vessel (10) according to one of claims 1 to 3, characterized in that at least the hollow cylindrical extension (20) of the outer shell (12) has a round outer contour (24) and a polygonal inner contour (22) with flat inner surfaces (26) and / or round inner surfaces (28). Pressure vessel (10) according to claim 4, characterized in that the planar connection surfaces (38) are formed in the region of the plane inner surfaces (26). 6. Pressure vessel (10) according to one of claims 1 to 5,  characterized in that  the outer shell (12) is made of a fiber-reinforced, preferably an endless fiber-reinforced plastic (CFRP, GFRP). 7. Pressure vessel (10) according to one of claims 1 to 6,  characterized in that  the outer shell (12) has a sheath structure (30) with a radially inner laminate layer (32) and a radially outer laminate layer (34) at least in the region of the fastening elements (36). 8. pressure vessel (10) according to claim 7,  characterized in that  the laminate layers (32, 34) have different fiber materials, wherein the radially inner laminate layer (32) remains undamaged when forming the planar connection surfaces (38). 9. pressure vessel (10) according to any one of claims 6 to 8,  characterized in that  the fiber composite plastic is a carbon fiber reinforced, preferably a continuous carbon fiber reinforced plastic (CFRP) or a glass fiber reinforced ter, preferably an endless glass fiber reinforced plastic (GRP). 10. Pressure vessel (10) according to one of claims 1 to 9,  characterized in that the outer shell (12) encloses a fluid-tight inner container (11) made of metal or fiber-reinforced plastic (CFRP, GFRP) or unreinforced plastic or forms the fluid-tight inner container (11) itself. 11. A method for producing an outer shell (12) for a pressure vessel (10), which is designed according to at least one of claims 1 to 10, with the steps:  Wrapping of an inner container (11) and / or a respective axially adjacent thereto winding mandrel with an endless fiber material, so that at both axial ends of the cylinder-like central portion (14) of the outer shell (12) each have a hollow cylindrical extension (20) is formed , which protrudes beyond the respective end region (16, 18), hardening of the outer shell (12), and  mechanical processing of the respective extension (20) in such a way that out of this, the fastening elements (36) are formed with the respective planar connection surfaces (38). 12. The method according to claim 11,  characterized in that  the wound continuous fiber material is provided with a matrix material before curing. 13. The method according to claim 11,  characterized in that  the continuous fibers are already preimpregnated with a matrix system. 14. The method according to any one of claims 11 to 13,  characterized in that  the respective winding mandrel has, at least in the region of the fastening elements (36) to be formed, a polygonal cross-section which is adapted to the flat connecting surfaces (38) to be formed.