DE102019212155A1 - Tubular pressure tank for storing fuel in a motor vehicle and manufacturing process (I) - Google Patents

Abstract

The invention relates to a tubular pressure tank (100) for storing fuel in a motor vehicle, comprising a cylindrical hollow body (110) and two end pieces (120) with which the hollow body (110) is closed on both sides, the end pieces (120) in the Hollow body ends (115) are arranged and fixed by radial deformation of the hollow body ends (115). According to the invention, it is provided that the end pieces (120) have a conical, outwardly tapering section (122) and the hollow body ends (115) are positively pressed onto these conical sections (122) of the end pieces (120). The invention also relates to a method for producing such a tubular pressure tank (100).

Description

The invention relates to a tubular pressure tank for storing fuel in a motor vehicle according to the preamble of claim 1. The invention also relates to a method for producing a tubular pressure tank.

A relevant tubular pressure tank is used in motor vehicles for storing fuel, in particular for storing hydrogen (H ₂ ) for a fuel cell drive or for storing natural gas (CNG) for a natural gas drive.

• - Bereitstellen des zylindrischen Hohlkörpers und der Abschlusstücke;
• - Verschließen der (offenen) Stirnseiten des zylindrischen Hohlkörpers mit den Abschlussstücken; und
• - Fixieren der Abschlussstücke durch formschlüssiges Verpressen mit dem zylindrischen Hohlkörper.

In the German patent application 10 2019 203 544.2 a tubular pressure tank ( 100 ) described, with a cylindrical hollow body ( 110 ), which is provided with end pieces ( 120 ) is closed. The end pieces (hereinafter referred to as end pieces) are arranged in the front ends of the cylindrical hollow body and are fixed to the cylindrical hollow body by direct form-fitting pressing. The manufacture of this pressure tank includes the steps:

• - Provision of the cylindrical hollow body and the end pieces;
• - Closing the (open) end faces of the cylindrical hollow body with the end pieces; and
• - Fixation of the end pieces by form-fitting pressing with the cylindrical hollow body.

The pressure tank according to the invention of claim 1 has an optimized fastening of the end pieces. With the independent patent claim, the invention also extends to a method for producing a pressure tank according to the invention. Preferred further developments and refinements of the invention result analogously for the pressure tank and for the manufacturing method from the dependent patent claims, the following description of the invention and the drawing.

The tubular or tubular pressure tank (pipe storage) according to the invention for storing fuel in a motor vehicle has an essentially cylindrical or tubular hollow body and two end pieces (end pieces, pipe end pieces) with which the cylindrical hollow body on both sides, i.e. H. is closed at both of its axial end faces. The end pieces are arranged in the (axial) hollow body ends of the cylindrical hollow body and are connected to the cylindrical hollow body by radial deformation of the hollow body ends and thereby fastened or held in place. According to the invention it is provided that the end pieces (each) have a conical or conical or frusto-conical shape that extends outwards (in the axial direction of the pressure tank), i.e. H. in an axial direction facing away from the inside of the tank, tapering section and that the hollow body ends of the cylindrical hollow body are positively pressed or pressed onto these conical sections of the end pieces.

The terminating pieces having a conical section are therefore arranged in the hollow body ends, by which the axial end sections or areas of the cylindrical hollow body are meant, and are fastened to the hollow body ends by direct or immediate form fit. The cylindrical hollow body or its hollow body wall (circumferential wall) is locally deformed or reshaped at its hollow body ends in the radial direction, in particular over the entire circumference, so that the hollow body ends of the cylindrical hollow body rest positively or contour-following at least on the conical sections of the end pieces. This creates a mechanical lock for the end pieces so that they are securely held in place even at high internal tank pressures and cannot be pushed out. Instead of a conical section, a paraboloid-shaped section or the like can also be provided on the end pieces with the same effect.

The conical sections of the end pieces can be formed (on their circumferential surfaces) with longitudinal grooves or similar groove-like depressions, which preferably extend essentially in the axial direction and which are in particular evenly distributed (i.e. at equal angular intervals) over the circumference. The hollow body ends pressed or pressed onto the conical sections of the end pieces are pressed into these longitudinal grooves. That is to say, the hollow body ends are deformed or reshaped radially inward in such a way that they also engage in the longitudinal grooves in a form-fitting manner or following the contour. With the longitudinal grooves, the formation of folds in the hollow body wall resulting from the conical diameter reduction can be prevented, in that these act as a kind of circumferential length compensation. It is therefore preferably provided that the longitudinal grooves in the conical sections of the end pieces (in the axial direction) are formed outwards with increasing or rising groove depth, in particular in such a way that the contour line in each cross section of a conical section has the same length (virtually the same circumference with reduced diameter). The longitudinal grooves and the positive locking with the hollow body wall or their hollow body ends generated above also increase the mechanical stability of the pressure tank and also act as an anti-twist protection for the end pieces.

The end pieces can also (each) have an outer cylindrical section that adjoins the conical section outwardly (in the axial direction), with the hollow body ends of the cylindrical hollow body also being pressed or pressed onto these outer cylindrical sections of the end pieces in a form-fitting or contour-following manner are. The above-described longitudinal grooves in the conical sections can extend into these outer cylindrical sections in order to prevent wrinkling there as well.

In the (axial) area of the outer cylindrical sections of the end pieces, additional reinforcements can be applied to the hollow body ends of the cylindrical hollow body. The reinforcements cause a circumferential reinforcement. Such reinforcements can, for example, be rings or sleeves, preferably made of metal and in particular made of steel, or wraps, for example wire wraps, fiber tape wraps or the like. The reinforcements, for example the rings or sleeves, can also be adapted to the longitudinal grooves described above and for this purpose can have corresponding form-locking elements on their inner circumferential surfaces, for example.

The outer cylindrical sections of the end pieces can protrude (in the axial direction) from the hollow body ends or protrude in the axial direction (outward), wherein the protruding or protruding subsections can function as bearing or fastening flanges for the pressure tank.

The cylindrical hollow body can have a liner and a fiber cladding applied to the liner, as will be explained in more detail below. It is preferably provided that the fiber cladding protrudes in the (axial) area of the hollow body ends in the axial direction over the liner, so that (in these protruding areas) only the fiber cladding on the end pieces, i.e. H. is pressed or pressed onto the conical sections and optionally also onto the outer cylindrical sections. That is to say, the conical sections and possibly also the outer cylindrical sections of the end pieces are only connected to the fiber sheathing of the cylindrical hollow body. There is thus no risk that the integrity of the liner will be compromised during the manufacture of the pressure tank.

As already mentioned, the cylindrical hollow body can be formed from a liner (inner sheath, inner tube) and a fiber sheathing (outer sheath, outer tube) applied to the liner. This structure can also be referred to as a composite pipe. The liner is formed in particular from plastic (e.g. polyethylene or polyamide) or metal (e.g. aluminum). The fiber cladding is in particular made of a fiber-reinforced, e.g. B. glass or carbon fiber reinforced plastic formed. The fiber sheathing is applied to the liner in particular by means of a pultrusion process (as described in German patent application 10 2018 222 302.5). The end pieces can be made of metal, e.g. B. made of steel or aluminum, in particular turned and / or milled parts. The metallic end pieces can be provided with an anti-corrosion coating. The end pieces can also be made of plastic (e.g. polyamide), possibly also of fiber-reinforced plastic, in particular injection molded parts.

• - Bereitstellen des (vorgefertigten) zylindrischen Hohlkörpers, wobei es sich insbesondere um ein Verbundrohr handelt, und der (vorgefertigten) Abschlussstücke;
• - Verschließen der (offenen) Stirnseiten des zylindrischen Hohlkörpers mit den Abschlussstücken, insbesondere durch (axiales) Einschieben der Abschlussstücke, sodass diese zumindest teilweise in den Hohlkörperenden bzw. in den Öffnungen an den stirnseitigen Enden des zylindrischen Hohlkörpers angeordnet sind;
• - Verbinden des zylindrischen Hohlkörpers mit den (eingeschobenen) Abschlussstücken, wozu die Hohlkörperenden des zylindrischen Hohlkörpers bzw. der Hohlkörperwandung radial (d. h. im Wesentlichen in radialer Einwärtsrichtung) auf die konischen Abschnitte der Abschlussstücke, gegebenenfalls auch auf die äußeren zylindrischen Abschnitte der Abschlussstücke, aufgepresst bzw. aufgedrückt werden (zwischen den Hohlkörperenden und den eingeschobenen Abschlussstücken bestehen axiale Überdeckungen, innerhalb derer das Aufpressen bzw. Aufdrücken erfolgt), insbesondere über den gesamten Umfang, sodass sich die Hohlkörperenden formschlüssig bzw. konturfolgend an die konischen Abschnitte der Abschlussstücke, gegebenenfalls auch an die äußeren zylindrischen Abschnitte der Abschlussstücke, anlegen und gegebenenfalls auch in die Längsnuten eingepresst werden.

The method according to the invention for producing a tubular pressure tank according to the invention comprises at least the following steps:

• - Provision of the (prefabricated) cylindrical hollow body, which is in particular a composite pipe, and the (prefabricated) end pieces;
• - Closing the (open) end faces of the cylindrical hollow body with the end pieces, in particular by (axially) pushing in the end pieces, so that they are at least partially arranged in the hollow body ends or in the openings at the front ends of the cylindrical hollow body;
• - Connecting the cylindrical hollow body to the (inserted) end pieces, for which purpose the hollow body ends of the cylindrical hollow body or the hollow body wall are pressed or pressed radially (ie essentially in the radial inward direction) onto the conical sections of the end pieces, possibly also onto the outer cylindrical sections of the end pieces . are pressed on (between the hollow body ends and the inserted end pieces there are axial overlaps within which the pressing or pressing takes place), in particular over the entire circumference, so that the hollow body ends form-fit or follow the contour of the conical sections of the end pieces, possibly also on the outer cylindrical sections of the end pieces, and if necessary also pressed into the longitudinal grooves.

The connection between the terminating pieces and the cylindrical hollow body or the hollow body ends and the fastening of the terminating pieces achieved therewith are preferably only effected by a form fit. In addition, however, it can be provided that the end pieces also with the cylindrical hollow body are glued (the adhesive can also act as a seal) and / or are fixed by means of locking rings or locking pins on the cylindrical hollow body. As a further optional step, reinforcement can be provided, in particular in the (axial) area of the outer cylindrical sections, e.g. B. by pulling on rings or sleeves and by wrapping wire or fiber tape.

As already explained, the provided cylindrical hollow body or the composite pipe can have a liner and a fiber cladding applied to the liner, which is formed in particular from a fiber-reinforced plastic. For pressing onto the end pieces, it is preferably provided that the cylindrical hollow body is heated locally at its hollow body ends, then deformed or reshaped (radially inward) and then cooled again, with provision in particular that the deformation force or the mold pressure is maintained during cooling is retained to prevent deformation. The fiber cladding can protrude over the liner in the axial direction in the area of the hollow body ends and form so-called protruding areas in the form of hollow-cylindrical extensions, which are then heated, deformed and cooled.

The fiber sheathing of the cylindrical hollow body or composite pipe is in particular made of a fiber-reinforced, e.g. B. glass or carbon fiber reinforced plastic formed. The plastic can be a thermoplastic plastic or a thermoplastic plastic matrix. For pressing onto the end pieces, the hollow body ends are heated to at least the material-specific softening temperature. The plastic can also be a thermosetting plastic or a thermosetting plastic matrix. For pressing onto the end pieces, the hollow body ends are then heated to a temperature above the glass transformation temperature (T _g ) associated with the thermoset material used and then reshaped (such as in DE 10 2005 050 925 A1 described). It is preferably provided that the plastic or the plastic matrix is a non-hardened or hardened resin (e.g. epoxy resin) or the like, which hardens or hardens only as a result of the heating when pressed onto the end pieces. The heating can take place, for example, by means of hot air or infrared radiation.

The radial pressing or pressing of the hollow body ends of the cylindrical hollow body or its hollow body wall onto the end pieces can take place in one step, if necessary also in several steps, by means of a pressure medium and / or a suitable pressing tool. It is preferably provided that for the (radial) pressing on of the hollow body ends a pressing tool is used which has a plurality of pressing jaws which are arranged in the manner of a chuck and (when pressing) perform a radial infeed movement. An electric, pneumatic or hydraulic drive can be provided for generating the force. The press jaws can be heated and can therefore also be used for heating. If necessary, the pressing on or pressing takes place in several steps (staggered deformation) with several such pressing tools.

• 1 zeigt in einer schematischen Schnittdarstellung (Längsschnitt) einen erfindungsgemäßen röhrenförmigen Drucktank.
• 2 zeigt einen Querschnitt durch das Abschlussstück des Drucktanks aus 1 gemäß dem in 1 angedeuteten Schnittverlauf (A-A).
• 3 veranschaulicht in einer schematischen Schnittdarstellung analog zur 2 einen Verfahrensschritt bei der Herstellung des Drucktanks aus 1.

The invention is explained in more detail below with reference to the drawing. The features shown in the figures of the drawing and / or explained below can be general features of the invention, also independently of certain combinations of features, and further develop the invention accordingly.

• 1 shows in a schematic sectional view (longitudinal section) a tubular pressure tank according to the invention.
• 2 shows a cross section through the end piece of the pressure tank 1 according to the in 1 indicated cutting course (AA).
• 3 illustrated in a schematic sectional view analogous to FIG 2 a process step in the manufacture of the pressure tank 1 .

1 shows the axial end portion of a tubular pressure tank 100 for storing fuel in a motor vehicle. The other axial end portion of the tubular pressure tank 100 is essentially identical or mirror-symmetrical. The pressure tank 100 has a cylindrical hollow body 110 on, which forms the pressure tank wall. The cylindrical hollow body 110 or its hollow body wall (circumferential wall) has a multi-layer structure (composite pipe), with a liner (inner sleeve, inner pipe) 112 made of plastic or metal, and one on the liner 112 applied fiber coating (outer shell, outer tube) 114 , which is formed from a fiber-reinforced plastic, in particular with a thermoset plastic matrix. In the area of the front ends of the pressure tank 100 or in the area of the hollow body ends 115 towers over the fiber coating 114 in the axial direction (with respect to the longitudinal axis L) the liner 112 and each forms a so-called protrusion area in the form of a tubular extension.

The cylindrical hollow body 110 has end pieces on both of its axial end faces 120 locked. The end pieces 120 are with an axial bore 125 with connecting thread designed so that a valve, a connection line or the like can be connected. The seal is made using O-rings 129 that are in circumferential grooves 128 are arranged and against the liner 112 seal. Are preferred on each end piece 120 at least two O-rings provided (double O-rings).

The end pieces 120 each have a first or (axially) inner, larger-diameter cylindrical section (axial section) 121 on. The outside diameter of the first or inner cylindrical sections 121 corresponds to the inside diameter of the (undeformed) cylindrical hollow body 110 . The end pieces 120 also each have a conical or frustoconical section (axial section) 122 and a second or (axially) outer, smaller diameter cylindrical section (axial section) 123 on, which (in the axial direction) outwards (ie facing away from the tank interior) to the first or inner cylindrical section 121 connect. The transitions between these axial sections are preferably rounded. The second or outer cylindrical sections 123 protrude in the axial direction from the hollow body ends 115 out or protrude, the protruding or protruding subsections 123a for the pressure tank 100 can serve as bearing or mounting flanges.

As in 1 indicated with dashed lines are the conical sections 122 the end pieces 120 on their conical outer circumferential surfaces with longitudinal grooves 126 or the like, which are formed in the axial direction outwards (ie in the axial direction facing away from the tank interior) with increasing groove depth and extend into the second or outer cylindrical sections 123 extend. How out 2 visible are the longitudinal grooves 126 Evenly distributed over the circumference and designed with a rounded groove profile. The longitudinal grooves 126 can be identical or different.

For fastening the end pieces 120 is the cylindrical hollow body 110 at the hollow body ends 115 , namely in the protruding areas of the fiber cladding 114 , radially (ie in the radial direction perpendicular to the longitudinal axis L) on the conical sections 122 and on the second or outer cylindrical sections 123 the end pieces 120 pressed on or pressed on, so that the hollow body ends 115 form-fitting or contour following on the conical sections 122 and the outer, smaller diameter cylindrical sections 123 issue. The hollow body ends 115 are also form-fitting or contour following in the longitudinal grooves 126 pressed in, like out 2 evident. Optionally, in the area of the second or outer cylindrical sections 123 additional reinforcements 130 , for example in the form of steel rings or sleeves, onto the hollow body ends 115 be upset, as in 1 shown.

The end pieces 120 based on the (axially) outside on the conical tapers or constrictions of the hollow body ends 115 from, the tapered or narrowed hollow body ends 115 quasi mechanical locks for the end pieces 120 form so that they cannot be reliably pushed out even at high internal tank pressures. The end pieces are supported towards the inside (axially) 120 on the liner 112 from what the first or inner cylindrical sections 121 the end pieces 120 each with a ring shoulder 127 are trained. The end pieces 120 are thereby fixed in both axial directions.

For the manufacture of the pressure tank 100 are the initially still undeformed hollow body ends 115 of the cylindrical hollow body or the composite pipe 110 heated and in the radial direction on the conical sections 122 and on the second or outer cylindrical sections 123 in the hollow body ends 115 inserted end pieces 120 pressed on or pressed on and also in the longitudinal grooves 126 pressed in. Pressing on and pressing in can be carried out using a pressing tool 200 as in 3 illustrated. The pressing tool 200 has several press jaws designed with corresponding shape contours 210 which are arranged like a chuck and perform a radial feed movement (when pressed on), as illustrated by the double arrows.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102005050925 A1 [0016]

Claims (10)

Tubular pressure tank (100) for storing fuel in a motor vehicle, having a cylindrical hollow body (110) and two end pieces (120) with which the hollow body (110) is closed on both sides, the end pieces (120) in the hollow body ends (115) arranged and fastened by radial deformation of the hollow body ends (115), characterized in that the end pieces (120) have a conical, outwardly tapering section (122) and the hollow body ends (115) form-fit onto these conical sections (122) of the end pieces (120) are pressed on. Tubular pressure tank (100) according to Claim 1 , characterized in that the conical sections (122) of the end pieces (120) are designed with longitudinal grooves (126), the pressed-on hollow body ends (115) also being pressed into these longitudinal grooves (126). Tubular pressure tank (100) according to Claim 2 , characterized in that the longitudinal grooves (126) are formed to the outside with increasing groove depth. Tubular pressure tank (100) according to one of the preceding claims, characterized in that the end pieces (120) furthermore have an outer cylindrical section (123) which adjoins the conical section (122) outwardly, the hollow body ends (115) also are positively pressed onto these outer cylindrical sections (123) of the end pieces (120). Tubular pressure tank (100) according to Claim 4 , characterized in that additional reinforcements (130) are applied to the hollow body ends (115) in the area of the outer cylindrical sections (123). Tubular pressure tank (100) according to Claim 4 or 5 , characterized in that the outer cylindrical sections (123) protrude from the hollow body ends (115), the protruding partial sections (123a) functioning as bearing flanges for the pressure tank (100). Tubular pressure tank (100) according to one of the preceding claims, characterized in that the cylindrical hollow body (110) has a liner (112) and a fiber cladding (114) applied to the liner (112), the fiber cladding (114) in the region of the Hollow body ends (115) protrudes in the axial direction over the liner (112) so that only the fiber sheathing (114) is pressed onto the end pieces (120). A method of manufacturing a tubular pressure tank (100) according to any one of the preceding claims, comprising the steps of: - Provision of the cylindrical hollow body (110) and the end pieces (120); - Closing the end faces of the cylindrical hollow body (110) with the end pieces (120); - Connecting the cylindrical hollow body (110) to the end pieces (120), for which purpose the hollow body ends (115) are pressed radially onto the conical sections (122) of the end pieces (120). Procedure according to Claim 8 , characterized in that the cylindrical hollow body (110) has a liner (112) and a fiber sheathing (114) applied to the liner (112), which is formed from a fiber-reinforced plastic, the hollow body ends (115) for pressing on the end pieces (120) are heated, then deformed and then cooled again. Procedure according to Claim 8 or 9 , characterized in that a pressing tool (200) is used for pressing on the hollow body ends (115) which has several pressing jaws (210) which are arranged like a chuck and which perform a radial feed movement.

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