EP3601870B1 - Pressurised container and method for producing an outer casing for a pressurised container - Google Patents

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 gases liquefied under pressure and therefore store a considerable amount of energy. For example, a so-called type 4 high-pressure container for compressed natural gas can be installed in a rear cargo space and / or below the floor in the area of a center tunnel of the vehicle body of a vehicle that is operated with natural gas.

A frequently used method for fastening pressure containers in the vehicle or under the vehicle uses tank straps which allow tolerance compensation when filling the container, but do not have any structural influence of the container rigidity on the body of the vehicle. In addition, evasion of the pressure tank in the event of plastic deformation of the body, for example in the event of a side crash, is ensured, which is intended to ensure protection against damage to the pressure tank. The crash energy is thus transmitted only through the components or load paths of the body.

A pressure vessel of the generic type preferably has a cylindrical design, in which a cylindrical pressure vessel jacket is closed on both sides by outwardly curved, end-face bases. The pressure vessel wall can, for example, have a three-layer structure and comprise an inner layer, a middle layer made of a fiber-reinforced plastic and an outer layer made of a further fiber-reinforced plastic. In the type 4 high-pressure container mentioned above, the inner layer is a plastic liner which is produced via blow molding or rotation / sintering processes or thermoforming processes. The middle layer reinforcing the plastic liner is preferably wound onto the plastic liner as a fiber winding in a wet winding process. As an example, the fiber winding consists of, for example, carbon, aramid, glass and / or boron fibers that are embedded in a matrix made of thermosets or thermoplastics. The fibers are applied to the plastic liner in different fiber orientations. The preferably impact-absorbing outer layer can also be a fiber winding that is wound onto the middle layer in a wet winding process. The outer winding formed in this way consists, for example, of carbon and / or glass fibers that are embedded in a matrix.

The finished high-pressure container has an outwardly protruding neck piece, in which a valve is integrated, on an end-side container bottom, for example. Otherwise, the high-pressure tank is usually completely smooth on the outside. In its installation position, the high-pressure container is secured in its position in common practice by means of tensioning straps that encompass the smooth-surfaced cylinder wall of the high-pressure container.

The WO 2016/173587 A1 discloses a polar cap for a pressure vessel for storing pressurized fluids, which is designed as a hybrid structure from an organic sheet with an injection-molded reinforcement structure and wherein the reinforcement structure of the organic sheet consists of thermoplastic material and is designed in the form of ribs.

The EP 3 289 276 A1 discloses a pressure vessel for storing pressurized fluids comprising at least a first polar cap, wherein this has a substantially axially extending area and is connected to at least one further container element by at least one reinforcement winding of at least one tape. The tape at least partially overlaps the axially extending area of the pole cap and an area of the further container element.

The FR 533 806 A discloses a container for transporting pressurized liquids, the container itself being provided with a cavity into which a utility accessory which can be protected from the outside by a movable cover can be inserted.

The DE 10 2015 222391 A1 relates to a fiber-reinforced pressure vessel with a dome cap and a method for producing such a pressure vessel.

The WO 2017/008899 A1 discloses a pressure tank assembly for storing and dispensing compressed fluidic fuels.

From the 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 to 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 vessel connection area and extend away from the outer surface of the pressure vessel. The pressure vessel connection areas each have an expansion. The connecting pin and the bearing are at least partially shaped and arranged at the connecting point in such a way that the extension E is kinematically guided by a movement of the bearing and / or the connecting pin with only one translational degree of freedom.

From the DE 10 2015 007 047 B4 a method for producing a pressurizable container is known which has a cylindrical central part made of a fiber plastic composite material the ends of which, in order to close the container, each have a base part made of a fiber plastic composite material. Here, 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 a roving. An inner surface of the bottom part is defined by the winding mandrel of the winding body and an end of the middle 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 being arranged one after the other from a winding axis of the winding body outwards on the winding axis, if a between the winding mandrel and the respective previously arranged shaping part formed partial winding space 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 incorporated into the body structure in a simple manner as a stiffening element.

This object is achieved by a pressure vessel with the features of claim 1 and by a method for producing an outer shell for a pressure vessel with the features of claim 11. Advantageous configurations with expedient further 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 easily integrated into the body structure as a stiffening element, a hollow cylindrical extension is formed at both axial ends of a cylinder-like central region of an outer shell, which over the respective end region protrudes and merges at its open end into a plurality of fastening elements, each of which has a planar 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 vessel and / or a respective winding mandrel axially adjoining this with a continuous fiber material, so that a hollow cylindrical extension is formed at both axial ends of the cylinder-like central region of the outer shell, which protrudes over the respective end area. The outer shell is hardened and the respective extension is mechanically processed in such a way that the fastening elements with the respective flat connection surfaces are formed therefrom. In this case, the wound continuous fiber material can be provided with a matrix material before hardening. Alternatively, the continuous fibers can already be pre-impregnated with the matrix system.

In an advantageous embodiment of the pressure vessel, the fastening elements can be designed as tabs. Here, the tabs can each have an opening through which a screw can be passed 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 post-machining process, in particular by milling or cutting. The planar connection surfaces can then be introduced into the fastening elements by a second machining post-processing, in particular by milling.

In a further advantageous embodiment of the pressure vessel, at least the hollow-cylindrical extension of the outer shell can 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 area of the planar inner surfaces. As a result, any number of connection surfaces can be implemented in different angular positions. 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 from a fiber-reinforced, preferably a continuous fiber-reinforced plastic. In addition, the outer shell can have a jacket structure with a radially inner laminate layer and a radially outer laminate layer, at least in the area of the fastening elements. Here, the laminate layers can have different fiber materials, it being possible for the radially inner laminate layer to remain undamaged when the flat connection surfaces are formed. The fiber composite plastic can be, for example, a carbon fiber reinforced, preferably a continuous carbon fiber reinforced plastic (CFRP), or a glass fiber reinforced, preferably a continuous glass fiber reinforced plastic (GFRP). Various fiber materials can be used in the manufacture of the outer shell, depending on the desired requirements, such as rigidity, strength, impact detection, etc. Here, for example, the layers of the inner laminate layer can be made from carbon fibers, the layers of the outer laminate layer can be made from glass fibers. Due to the superficial damage to the outer laminate layer to represent the flat connection surfaces in the milling process, only the glass fibers but not the carbon fibers of the inner laminate layer are released. The structural properties of the carbon fiber matrix composite are therefore retained, and corrosive interactions with metallic components in the area where the vehicle body structure is attached can be avoided.

In a further advantageous embodiment of the pressure vessel, the outer shell can enclose a fluid-tight inner container made of metal or made of fiber-reinforced plastic or of unreinforced plastic over a large area, or it can 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 can have a polygonal cross section adapted to the planar connection surfaces to be formed, at least in the area of the fastening elements to be formed. This results in different radii in the areas of the round for the inner contour of the shell structure of the outer shell Inner surfaces and the areas of the flat inner surfaces. As a result, the thread tension in the winding process is unequal, which is why the thread can become detached from the tool core in the areas with higher radii. In these areas, due to the constant radius of the outer contour of the jacket structure of the outer casing, a greater wall thickness and thus a partially lower fiber volume content are formed.

The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination, but also in other combinations or on their own, without the scope of the Invention to leave. There are thus also embodiments to be regarded as encompassed and disclosed by the invention, which are not explicitly shown or explained in the figures, but emerge from the explained embodiments and can be generated by separate combinations of features.

Fig. 1

eine schematische perspektivische Darstellung eines Innenbehälters für einen erfindungsgemäßen Druckbehälter;

Fig. 2

eine schematische perspektivische Darstellung des mit einer Außenhülle umwickelten Innenbehälters aus Fig. 1 vor einer mechanischen Bearbeitung;

Fig. 3

eine schematische Schnittdarstellung der Außenhülle im Bereich eines hohlzylindrischen Fortsatzes,

Fig. 4

eine Darstellung eines Details IV aus Fig. 3,

Fig. 5

eine schematische perspektivische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen Druckbehälters; und

Fig. 6

eine Darstellung eines Details VI aus Fig. 6.

An embodiment of the invention is shown in the drawing and is explained in more detail in the following description. In the drawing, the same reference symbols designate components or elements that perform the same or analogous functions. Here show:

Fig. 1

a schematic perspective illustration of an inner container for a pressure vessel according to the invention;

Fig. 2

a schematic perspective illustration of the inner container wrapped with an outer shell Fig. 1 before mechanical processing;

Fig. 3

a schematic sectional view of the outer shell in the area of a hollow cylindrical extension,

Fig. 4

a representation of a detail IV Fig. 3 ,

Fig. 5

a schematic perspective illustration of an embodiment of a pressure vessel according to the invention; and

Fig. 6

a representation of a detail VI Fig. 6 .

How out Figs. 1 to 6 As can be seen, the illustrated embodiment of a pressure vessel 10 according to the invention comprises an outer shell 12 which has a cylinder-like central region 14 and two adjoining end regions 16, 18. At both axial ends of the cylinder-like central region 14 of the outer shell 12, a hollow-cylindrical extension 20 is formed which protrudes 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, each of which has a planar connection surface 38 arranged radially on the outside.

How out Fig. 2 and 5 As can also be seen, the outer shell 12 in the illustrated embodiment encloses the fluid-tight inner container 11 over a large area. The fluid-tight inner container 11 can be made, for example, of metal or of fiber-reinforced plastic (CFRP, GFRP) or of non-reinforced 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 is, for example, a carbon fiber reinforced, preferably a continuous carbon fiber reinforced plastic (CFRP) and / or a glass fiber reinforced, preferably a continuous glass fiber reinforced plastic (GFRP).

According to the method for producing an outer shell 12 for a pressure vessel 10, the in Fig. 1 shown inner container 11 and at both ends axially adjoining winding mandrels, not shown, wrapped with a continuous fiber material so that a hollow cylindrical extension 20 is formed at both axial ends 16, 18 of the cylinder-like central region 14 of the outer shell 12, which over the respective end region 16, 18 survives as out Fig. 2 can be seen further. The wound continuous fiber material is then provided with a matrix material. Alternatively, the continuous fibers can already be pre-impregnated with the matrix system. The outer shell 12 then hardens. In the exemplary embodiment shown, the respective winding mandrel has, at least in the area of the fastening elements 36 to be formed, a polygonal cross section that is adapted to the flat connection surfaces 38 to be formed.

How out Figures 3 and 4 As can also be seen, 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 planar inner surfaces 26 and round inner surfaces 28. How out Figures 3 and 4 As can also be seen, the inner contour 22 is sixteen-sided 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 larger than on the round inner surfaces 28 of the inner contour. As a result, the thread tension in the winding process is unequal, which is why the thread can become detached from the tool core in the areas with higher radii. In these areas, due to the constant radius of the outer contour 24 of the jacket structure 30 of the outer sheath 12, a greater wall thickness and thus a partially lower fiber volume content are formed.

Like in particular from Figures 3 and 4 As can also be seen, the outer shell 12 has, at least in the area of the fastening elements 36, a jacket structure 30 with a radially inner laminate layer 32 and a radially outer laminate layer 34. To generate the jacket structure 30, different fiber materials can be used according to the desired requirements, such as rigidity, strength, impact detection, etc. In the illustrated embodiment, the inner laminate layer 32 is made from carbon fiber layers and the outer laminate layer 34 is made from glass fiber layers.

After the outer shell 12 has hardened, the extensions 20 are mechanically processed according to the invention in such a way that the fastening elements 36 with the respective planar connection surfaces 38 are formed therefrom. Here the fastening elements 36 are introduced into the respective hollow-cylindrical extension 20 by a first machining post-processing, for example by milling or cutting. Subsequently, the planar connection surfaces 38 are introduced into the fastening elements 36 by a second machining post-processing, for example by milling. How out Figures 5 and 6 As can also be seen, the fastening elements 36 in the illustrated embodiment are designed as tabs 36A, each of which has a fastening opening. Screws can be passed through the fastening openings in order to screw the pressure vessel 10 to a body structure (not shown) of a vehicle.

In addition, the planar connection surfaces 38 are formed in the area of the planar inner surfaces 26. Furthermore, the radially inner laminate layer 32 remains undamaged when the flat connection surfaces 38 are formed. Thus, due to the superficial damage to the outer laminate layer 34 to represent the planar connection surfaces 38 in the milling process, only the glass fibers of the outer laminate layer 34, but not the carbon fibers of the inner laminate layer 32, are released. Therefore, the structural properties of the carbon fiber matrix composite of the inner laminate layer 32 are advantageously retained. In addition, corrosive interactions with metallic components in the connection area of the body structure of the vehicle are advantageously avoided.

REFERENCE LIST

10

pressure vessel

11

Inner container

12

Outer shell

14th

Midrange

16, 18

End area

20th

Appendix

22nd

Inner contour

24

Outer contour

26th

flat inner surface

28

round inner surface

30th

Jacket structure

32

inner laminate layer

34

outer laminate layer

36

Fastener

36A

Tab

38

Connection area

Claims (14)

1. Pressurised container (10) with an outer casing (12), which has a cylinder-like central region (14) and two end regions (16, 18) attached thereto, wherein a hollow-cylindrical extension (20) is 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), characterised in that 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.
2. Pressurised container (10) according to claim 1, characterised in that the fastening elements (36) are designed as lugs (36A).
3. Pressurised container (10) according to claim 1 or 2, characterised in that the fastening elements (36) are incorporated into the corresponding hollow-cylindrical extension (20) by means of a first stock removal finishing process, wherein the planar connection faces (38) are incorporated into the fastening elements (36) by means of a second stock removal finishing process.
4. Pressurised container (10) according to any of claims 1 to 3, characterised in that at least the hollow-cylindrical extension (20) of the outer casing (12) has a round outer contour (24) and a polygonal inner contour (22) with planar inner surfaces (26) and/or round inner surfaces (28).
5. Pressurised container (10) according to claim 4, characterised in that the planar connection faces (38) are formed in the region of the planar inner surfaces (26).
6. Pressurised container (10) according to any of claims 1 to 5, characterised in that the outer casing (12) is made from a fibre-reinforced, preferably a continuous fibre-reinforced plastic (CFC, GRC).
7. Pressurised container (10) according to any of claims 1 to 6, characterised in that, at least in the region of the fastening elements (36), the outer casing (12) has a shell structure (30) with a radially inner laminate layer (32) and a radially outer laminate layer (34).
8. Pressurised container (10) according to claim 7, characterised in that the laminate layers (32, 34) have different fibre materials, wherein the radially inner laminate layer (32) remains undamaged during forming of the planar connection faces (38).
9. Pressurised container (10) according to any of claims 6 to 8, characterised in that the fibre-reinforced plastic is a carbon fibre-reinforced, preferably a continuous carbon fibre-reinforced plastic (CFC) or a glass fibre-reinforced, preferably a continuous glass fibre-reinforced, plastic (GFC).
10. Pressurised container (10) according to any of claims 1 to 9, characterised in that the outer casing (12) completely encloses a fluid-tight inner container (11) made from metal or fibre-reinforced plastic (CFC, GFC) or non-reinforced plastic or itself forms the fluid-tight inner container (11).
11. Method for producing an outer casing (12) for a pressurised container (10), which, according to at least one of claims 1 to 10, is formed by the steps of:
    Wrapping an inner container (11) and/or a winding mandrel joined axially to it in each case with a continuous fibre material, such that at both axial ends of the cylinder-like central region (14) of the outer casing (12) a hollow-cylindrical extension (20) is formed in each case, which projects beyond the respective end region (16, 18), curing the outer casing (12), and machining the respective extension (20) such that the fastening elements (36) with the respective planar connection faces (38) are formed therefrom.
12. Method according to claim 11, characterised in that the wound continuous fibre material is provided with a matrix material prior to curing.
13. Method according to claim 11, characterised in that the continuous fibres are already pre-impregnated with a matrix system.
14. Method according to any of claims 11 to 13, characterised in that the particular winding mandrel has a polygonal cross-section, at least in the region of the fastening elements (36) to be formed, and has a polygonal cross-section tailored to the planar connection faces (38) to be formed.

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