Pressure tank for a gas-operated vehicle

Abstract

The invention relates to a pressure tank (1) for storing gas as a fuel, suitable for mounting in a gas-operated vehicle (20), in particular in a utility vehicle, wherein the pressure tank (1) has a longitudinal axis (t) and has a rotationally symmetrical, elongate shape which is cylindrical in the central region and is closed at both ends by curved pole caps, and further comprises a wall (2) which encloses a cavity for storing the gas, and a metal connection piece, known as a boss (3), on each of the pole caps, wherein the wall comprises a reinforcing layer made of fibre-reinforced plastic and comprises an inner liner for sealing purposes, and wherein the pressure tank (1) has at least one holder (10) for at least partially absorbing the weight force and for fastening the pressure tank (1) to a supporting structure (21) of the vehicle, wherein the holder (10) is in the form of a metal sheet which has an accommodating bore (12) through which the boss (3) is inserted, which metal sheet is fastened to the boss (3) by clamping and has a plurality of holding tabs (11) each having at least one fastening bore (13) for fastening to the support structure (21), wherein the holding tabs (11) are oriented perpendicular to the longitudinal axis (t) of the pressure tank.

Description

[0001] Pressure tank for gas-powered vehicle

[0002] The invention relates to a pressure tank for storing gas for installation in a gas-powered vehicle as a fuel tank. The pressure tank has a longitudinal axis t and a rotationally symmetrical, elongated shape, cylindrical in the central region and closed at both ends by curved pole caps. The pressure tank has a wall enclosing a cavity for storing the gas, as well as a metallic connecting piece, a so-called boss, at each of the two pole caps. The wall comprises a reinforcing layer made of fiber-reinforced plastic and an internal liner for sealing. Furthermore, the pressure tank comprises a bracket for absorbing the weight force and for attaching the pressure tank to a vehicle.

[0003] Gas-powered vehicles, for example, are powered by a gas engine or a fuel cell with an electric motor. To store sufficient fuel, the gas, which can be hydrogen, is stored in the tank under high pressure. Pressures of over 200 bar, often up to 600 bar, and sometimes even up to 700 or 800 bar, are typical for such pressure tanks. This means that the pressure tank must not only be gas-tight under this pressure, but also require high mechanical stability and be securely mounted in the vehicle.

[0004] Pressure tanks for gas-powered vehicles are known in the prior art. These pressure tanks have a wall that includes an internal liner, for example, made of thermoplastic, for sealing, and a reinforcement layer made of fiber-reinforced plastic to provide mechanical stability. The reinforcement layer is preferably wound and designed as a CFRP layer. CFRP stands for carbon fiber reinforced plastic. Such pressure tanks are referred to as Type IV.

[0005] The boss has a through-hole and a connection thread. At least one of the two bosses is connected to a tank fitting, which allows for filling the pressure tank or controlled gas withdrawal. On the other boss, the through-hole is sealed with a cap, or another tank fitting or safety valve is provided.

[0006] Such pressure tanks are known from the state of the art, as are various options for attaching the pressure tanks to the vehicle or to a supporting structure. The supporting structure serves to establish the connection between the pressure tanks and the vehicle and can be designed, for example, as a rack or frame.

[0007] DE 2020134640 A1 shows pressure tanks for commercial vehicles that are attached to a vehicle support structure with tensioning straps and a lower bracket that engages the boss and is designed as a so-called conical mount. The support structure can accommodate several pressure tanks and is attached to the vehicle. Especially for longer pressure tanks, such as those used in commercial vehicles, a certain degree of axial length compensation is necessary to ensure compensation for the longitudinal expansion of the pressure tank under changing temperatures and pressures.

[0008] The disadvantage of these mounts is that they require a lot of axial space and are complex and expensive. To mount the conical bearing on the boss, the boss neck must be specially extended.

[0009] US 11041591 B1 shows another design of pressure tanks for commercial vehicles with a bracket that engages the boss. The pressure tanks are attached horizontally to the vehicle using two such brackets, which are designed as a sheet metal bracket. The bracket has a mounting hole into which the neck of the boss is received. The bracket is fixed to the boss using a retaining ring. This bracket offers good flexibility in the axial direction, but is not sufficiently durable. The simple retaining ring only provides inadequate long-term fixation of the bracket to the boss, as vibrations cause the bracket to hit the boss with the edge of the mounting hole, thus creating ever-increasing play between the pressure tank and the bracket. This increased play poses the risk that gas lines or attachments connected to the pressure tank will leak or even break off.Especially for larger and heavier pressure tanks for commercial vehicles, this mount is neither safe nor reliable in the long term.

[0010] The pressure tanks and their mounting brackets known in the state of the art do not currently offer sufficiently flexible yet durable mounting of the pressure tanks in the vehicle. Improved mounting of the pressure tanks is particularly necessary for commercial vehicles that require multiple and larger pressure tanks for fuel to ensure sufficient range and where space-saving arrangement is particularly important.

[0011] The object of the invention is to provide a pressure tank with improved support.

[0012] The object is achieved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention can be found in the subclaims.

[0013] According to the invention, the pressure tank holder is characterized in that it is designed as a sheet metal member having a receiving bore through which the boss is inserted, which is secured to the boss by a clamp, and which has a plurality of mounting brackets, each with at least one mounting bore for attachment to the supporting structure, wherein the mounting brackets are aligned perpendicular to the longitudinal axis t of the pressure tank. The boss has a neck that is inserted through the receiving bore of the holder. The clamping takes place at the neck of the boss.

[0014] The advantage of this solution is that the clamping mechanism prevents the bracket from having any play in relation to the boss, meaning it won't deflect or damage the boss's neck, even under vibration or heavy loads. This ensures long-term, reliable attachment of the pressure tanks to the supporting structure. At the same time, the bracket offers the option of providing sufficient flexibility in the axial direction to compensate for longitudinal expansion of the pressure tank. The flexibility of the bracket in the longitudinal direction t can be specifically adjusted using the thickness and three-dimensional bending of the sheet metal. Furthermore, thanks to the clever alignment of the bracket tabs, the bracket requires very little installation space in the axial direction, allowing the pressure tank to be made longer with the same overall installation space. The combination of these properties is a significant improvement over the state of the art.In addition, such a bracket made of sheet metal is inexpensive and easy to produce in large quantities.

[0015] It is also advantageous if the clamping of the bracket to the boss is designed in such a way that the inner edge of the mounting hole cannot come into direct contact with the boss, in particular with the neck of the boss. This can be achieved, for example, by sliding a spacer sleeve onto the neck of the boss or screwing a nut on so that it is positioned between the inner edge of the mounting hole and the neck of the boss. This prevents the inner edge of the mounting hole from damaging the boss, in particular the neck of the boss, and from penetrating it. Since the bracket is usually made of steel and the boss is usually made of aluminum, the boss would otherwise not be able to withstand this load permanently. If it were pierced, the pressure tank would also become increasingly loose in the bracket, and there would be a risk that gas lines or other attachments to the pressure tank would leak or break off.

[0016] In a preferred embodiment, the bracket is designed as a folded sheet metal in such a way that it is sufficiently flexible in the direction of the longitudinal axis t to be able to compensate for longitudinal expansion of the pressure tank and thus for displacement of the boss. The type of bend and the thickness of the sheet metal can be used to specifically adapt the flexibility to the expected load and the weight of the pressure tank. In order to prevent excessive displacement of the pressure tank in the longitudinal direction t and thus damage, at least one stop can be provided on the pressure tank, which limits the flexible displacement of the boss (3) in the longitudinal direction t by arranging the boss such that it comes into contact with one or more mounting brackets after the permissible displacement. Since the mounting brackets are fixedly connected to the support structure, the mounting brackets can absorb the forces and thus reliably limit the displacement of the pressure tank.

[0017] Advantageously, the pressure tank comprises a pole cap protector. The stop can preferably be provided on the pole cap protector of the pressure tank and can be designed, in particular, as an annular or discontinuous annular projection. It can also be formed from one or more ribs of the pole cap protector. The stop can be made of the same polymer material as the pole cap protector.

[0018] As an alternative to a flexible mount, the mount can be designed so rigid that no flexible displacement of the boss in the longitudinal direction t is permitted. This can be achieved, for example, by selecting a sharper bend and / or a greater sheet thickness. This type of mount enables precise positioning of the pressure tank in the vehicle.

[0019] In a particularly preferred embodiment, a bracket is provided on each of the two bosses of the pressure tank, one of the brackets being designed as a folded sheet metal in such a way that it is sufficiently flexible in the direction of the longitudinal axis t to be able to compensate for longitudinal expansion of the pressure tank and thus for displacement of the boss, and the other bracket being designed so rigid that no flexible displacement of the boss in the longitudinal direction t is permitted. In this way, the pressure tank can be reliably and precisely fastened in the vehicle and, at the same time, sufficient compensation for longitudinal expansion due to temperature or pressure changes is possible. The flexible bracket can, in particular, have one or more of the advantageous features described above.

[0020] It is also advantageous if the bracket is clamped via a nut that is screwed onto an external thread on the boss. Additionally, the nut can have a centering rib for the mounting hole of the bracket. This improves the clamping or radial positioning of the bracket on the boss. The centering rib can, in particular, be designed so that it is positioned between the inner edge of the mounting hole and the neck of the boss. This ensures that the inner edge does not come into direct contact with the boss.

[0021] It's also advantageous if the boss, especially at its neck, has a ridged shoulder that supports the boss on the mount. This provides a counter surface for the clamp. This results in a particularly good clamping effect, especially when used in conjunction with a nut screwed onto the boss.

[0022] Furthermore, an intermediate ring can be provided, which is arranged between the shaft shoulder and the bracket. This allows for easier production of the external thread on the boss neck, since the thread runout is bridged by the intermediate ring, on which the bracket can rest.

[0023] Further advantageous features of the invention are explained using exemplary embodiments with reference to the drawings. These features can be advantageously implemented not only in the illustrated combination, but also individually combined with one another. The figures show in detail:

[0024] Fig.1 Pressure tank according to the invention in a gas-powered vehicle

[0025] Fig.2 Pressure tank according to the invention in section

[0026] Fig.3a Schematic representation of an embodiment of the holder on the pressure tank according to the invention Fig.3b Schematic representation of a further embodiment of the holder on the pressure tank according to the invention

[0027] Fig.4a / b Detailed view of an embodiment of the holder on the pressure tank according to the invention

[0028] Fig.5 Example of mounting plate

[0029] Fig.6a / b Detailed view of another embodiment of the holder on the pressure tank according to the invention

[0030] The figures are described in more detail below. Like reference numerals indicate like or similar parts or components.

[0031] Fig. 1 shows one or more pressure tanks 1 according to the invention, which are fastened to the support structure 21 and mounted thereon in the vehicle 20. The pressure tanks 1 serve, for example, as fuel tanks for hydrogen, which is used to operate the gas-powered commercial vehicle 20. The pressure tanks 1 are fastened to one or both bosses 3 via the bracket 10 and, if appropriate, optionally via the articulated band clamp 22 to the support structure 21. In particular, if a bracket 10 is present on both bosses 3, the articulated band clamp 22 can be omitted. The pressure tanks 1 are preferably mounted vertically in the vehicle 20. This means that the fastening of the pressure tanks 1 must be designed such that it can reliably absorb the weight force in the direction of the longitudinal axis t of the pressure tank.

[0032] Fig. 2 shows the pressure tank 1 according to the invention with a boss 3 on each of the two pole caps. A tank fitting 4 for filling and controlled removal of gas is screwed into the lower boss 3. The upper boss 3 is closed with a plug 5. Alternatively, a safety valve can be screwed into this boss 3. The wall 2 of the pressure tank encloses the cavity for storing the gas and is formed by an internal liner and a reinforcement layer. The liner is preferably made of thermoplastic such as polyamide and is often manufactured by blow molding or injection molding. The reinforcement layer is produced by a winding process with tapes made of fiber-reinforced plastic, preferably CFRP (carbon fiber reinforced plastic). The pressure tank 1 is rotationally symmetrical about the longitudinal axis t. The radial direction is designated R.With such pressure tanks, special attention must be paid to the reliable attachment of the pressure tank 1. Especially with large pressure tanks 1, such as those required in commercial vehicles to ensure sufficient range, secure attachment to the vehicle is a demanding challenge. The brackets 10 are attached to the respective boss 3 and secured thereto via a clamp. The brackets 10 serve to securely and reliably attach the pressure tank 1 to the support structure 21. They support the weight of the pressure tank 1.

[0033] In Fig.3a, a design for the holder 10 is shown in detail. The holder

[0034] 10 is designed as a sheet metal that is folded so that the fastening tabs 11 are aligned perpendicular to the longitudinal axis t. The fastening holes 13, through which the pressure tank 1 can be screwed to the support structure 21, are located on the fastening tabs 11. The flexibility of the bracket 10 in the direction of the longitudinal axis t can be specifically adjusted by the height and type of folding and the thickness of the sheet. This allows the boss 3 to move along the longitudinal axis t when the pressure tank 1 expands. The folding is designed so that it is directed away from the pressure tank 1 in order to

[0035] 11 to get a little more space for assembly.

[0036] The bracket 10 has a mounting hole 12 in the center through which the boss 3, in this case the neck of the boss, is inserted. The neck of the boss also has a shaft shoulder 7, which is designed so that the bracket 10 rests on this shaft shoulder. The bracket 10 is clamped to the boss 3 via a nut 16, which is screwed onto the external thread 8 on the neck of the boss. The nut 16 encloses the centering web 17, which engages in the mounting hole 12 and thus prevents the inner edge of the mounting hole from coming into direct contact with the neck of the boss. This also ensures the exact positioning of the bracket 10 relative to the boss 3. To simplify production and assembly, an intermediate ring 15 is provided between the boss 3 and the bracket, which bridges the runout of the external thread 8 and on which the bracket 10 rests. This allows the external thread 8 to be applied to the neck of the boss without any additional effort.

[0037] The bracket 10 is so space-saving due to the design according to the invention that it does not require any additional installation space in the longitudinal direction and no extra extended Boss 3.

[0038] Fig. 3b shows another design for the bracket 10 and the pressure tank 1. This bracket 10 is also designed to be flexible in the direction of the longitudinal axis t. Here, the bending occurs towards the pressure tank 1. Thus, the fastening tabs 11 provide a support surface for the stops 9, which are intended to limit the displacement of the boss 3 to a desired extent. This prevents attachments or gas lines from being displaced excessively and thus becoming damaged. The stop 9 is designed here as part of the pole cap protection 6. For example, the stop 9 can be ring-shaped or segment-shaped.

[0039] A variant not shown is that the stop 9 is formed on the holder 10 and is supported on a support surface on the wall 2 or on the pole cap protection 6 and thereby limits the maximum displacement path.

[0040] Figs. 4a and 4b show a design of the flexible bracket 10 on the pressure tank - one without and one with the tank fitting 4 screwed in. The design corresponds to the variant shown in Fig. 3a. The sheet metal of the bracket is X-shaped with four arms. The width of the arms thus acts as an additional factor influencing flexibility. This width can also be selected to achieve the desired level of flexibility. For example, two fastening holes 13 are provided in each of the fastening tabs 11 to mount the bracket 10 to the supporting structure 21 of the vehicle. The nut 16 clamps the bracket 10 onto the neck of the boss 3. The tank fitting 5 is screwed into an internal thread of the boss. Fig. 5 shows a further variant of the bracket 10. This bracket 10 is designed such that it has virtually no flexibility in the direction of the longitudinal axis t.The sheet metal is bent to ensure rigidity of the bracket 10. The bracket tabs 11 each have two mounting holes 13. In the center of the bracket 10 is the mounting hole 12, into which the neck of the boss 3 is inserted.

[0041] In Fig.6a and 6b, the pressure tank 1 can be seen with this rigid holder 10 - once without and once with screwed-in plug 5. The plug 5 can optionally also be designed as a safety valve.

[0042] A preferred embodiment of the pressure tank 1 comprises a flexible bracket 10 in the direction of the longitudinal axis t on one boss 3 and a rigid bracket 10 on the other boss 3. This allows the pressure tank 1 to be securely and precisely attached to the support structure 21 of the vehicle and, on the other hand, allows it to expand slightly in the direction of the longitudinal axis t without placing excessive strain on the brackets 10.

[0043] List of reference symbols

[0044] 1 pressure tank

[0045] 2 wall

[0046] 3 Boss

[0047] 4 Tank fitting

[0048] 5 plugs

[0049] 6 Polar cap protection

[0050] 7 wave heel

[0051] 8 external threads

[0052] 9 stop

[0053] 10 Bracket

[0054] 11 Mounting bracket

[0055] 12 mounting hole

[0056] 13 Mounting hole

[0057] 15 intermediate ring

[0058] 16 Mother

[0059] 17 Centering bar

[0060] 20 vehicles

[0061] 21 Supporting structure

[0062] 22 Joint band clamp t Longitudinal axis of the pressure tank

[0063] R Radial direction of the pressure tank

Claims

Patent claims 1. A pressure tank (1) for storing gas as a fuel, suitable for installation in a gas-powered vehicle (20), in particular in a commercial vehicle, wherein the pressure tank (1) has a longitudinal axis t and a rotationally symmetrical, elongated shape, which is cylindrical in the central region and closed at both ends by curved pole caps. It further comprises a wall (2) enclosing a cavity for storing the gas, as well as a metallic connecting piece, a so-called boss (3), on each of the pole caps. The wall comprises a reinforcing layer made of fiber-reinforced plastic and an internal liner for sealing. The pressure tank (1) has at least one holder (10) for at least partially absorbing the weight force and for fastening the pressure tank (1) to a supporting structure (21) of the vehicle.which has a receiving bore (12) through which the boss (3) is inserted, which is fastened to the boss (3) by a clamp, and which has a plurality of mounting brackets (11), each with at least one mounting bore (13) for attachment to the support structure (21), wherein the mounting brackets (11) are aligned perpendicular to the longitudinal axis t of the pressure tank.

2. Pressure tank (1) according to claim 1, characterized in that the clamping of the holder (10) on the boss (3) is designed in such a way that the receiving bore (12) on its inner edge does not come into direct contact with the boss (3), in particular by pushing a spacer sleeve onto the neck of the boss (3) or screwing a nut (16) onto it in such a way that it is arranged between the inner edge of the receiving bore (12) and the neck of the boss (3).

3. Pressure tank (1) according to claim 1 or 2, characterized in that the holder (10) is designed as a folded sheet metal, in such a way that it is sufficiently flexible in the direction of the longitudinal axis t to be able to compensate for a longitudinal expansion of the pressure tank (1) and thus a displacement of the boss (3).

4. Pressure tank (1) according to claim 3, characterized in that a stop (9) is provided on the pressure tank (1) which limits the flexible displacement of the boss (3) in the longitudinal direction t, in that this stop (9) is arranged in such a way that it comes into contact with one or more holding tabs (11) after the permissible displacement.

5. Pressure tank (1) according to claim 4, characterized in that a pole cap protector (6) is provided on the pressure tank (1) and that the stop (9) is provided on the pole cap protector (6) of the pressure tank, in particular designed as an annular or interrupted annular projection.

6. Pressure tank (1) according to claim 1 or 2, characterized in that the holder (10) is designed so rigid that no flexible displacement of the boss (3) in the longitudinal direction t is permitted.

7. Pressure tank (1) according to one of the preceding claims, characterized in that a holder (10) is provided on each of the two bosses (3), wherein one holder (10) is designed as a folded sheet metal, in such a way that it is sufficiently flexible in the direction of the longitudinal axis t to be able to compensate for a longitudinal expansion of the pressure tank (1) and thus a displacement of the boss (3), and the other holder (10) is designed so rigid that no flexible displacement of the boss (3) in the longitudinal direction t is permitted.

8. Pressure tank (1) according to one of the preceding claims, characterized in that the holder (10) is clamped via a nut (16) which is screwed onto an external thread (8) on the boss (3).

9. Pressure tank (1) according to claim 8, characterized in that the nut (16) has a centering web for the receiving bore (12) of the holder.

10. Pressure tank (1) according to one of the preceding claims, characterized in that the boss (3) has a shaft shoulder (7) via which the boss (3) is supported on the holder (10).

11. Pressure tank (1) according to claim 10, characterized in that an intermediate ring (15) is provided which is arranged between the shaft shoulder (7) and the holder (10).

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