Fuel container for a motor vehicle and method for producing such a fuel container, and reinforcing element for a fuel container

Abstract

Fuel tank for a motor vehicle, comprising a plastic wall which delimits a storage volume for storing fuel, comprising one or more reinforcing elements for reinforcing the plastic wall, with at least one reinforcing element being connected to an outer side of the plastic wall that faces away from the storage volume, characterized in thata maximum thickness of at least one reinforcing element measured normal to the plastic wall is greater than the wall thickness of the plastic wall.

Claims

1. A reinforcing element for fuel tank for a motor vehicle, wherein the reinforcing element has at least one blind hole, which is designed for being gripped with a gripper, wherein the fuel tank comprises a plastic wall that delimits a storage volume for storing fuel, wherein the reinforcement element is configured to be connected to an outer side of the plastic wall that faces away from the storage volume at a connection region, wherein a maximum thickness of the reinforcing element, when measured normal to the plastic wall, exceeds a wall thickness of the plastic wall, and wherein the reinforcing element is arranged in a transition selected from the group consisting of a transition from a side wall to a tank top and a transition in front of a side wall to a tank bottom, wherein the reinforcing element is tapered on two sides starting from a region of the maximum thickness.

2. A fuel tank for a motor vehicle, the fuel tank comprising a plastic wall, which delimits a storage volume for storing fuel, and one or more reinforcing elements for reinforcing the plastic wall, the one or more reinforcing elements comprising at least one reinforcing element, wherein the at least one reinforcing element is connected to an outer side of the plastic wall that faces away from the storage volume, wherein a maximum thickness of the at least one reinforcing element, measured normal to the plastic wall, is greater than a wall thickness of the plastic wall, wherein the at least one reinforcing element is arranged in a transition selected from the group consisting of a transition from a side wall to a tank top and a transition in front of a side wall to a tank bottom, wherein the reinforcing element is tapered on two sides starting from a region of the maximum thickness, and wherein the at least one reinforcing element has a substantially triangular or crescent-shaped basic shape.

3. The fuel tank of claim 2, wherein the plastic wall has a first half-shell and a second half-shell that are circumferentially welded to one another in a region of the side wall, the first half-shell being an upper shell that comprises the tank top and the second half-shell being a lower shell that comprises the tank bottom.

4. The fuel tank of claim 2, wherein the at least one reinforcing element has at least one tapered end portion that has a thickness of 5 mm or less over an end portion length of 20 mm or less and that is tapered in a wedge shape.

5. The fuel tank of claim 2, wherein an end connection region of the at least one reinforcing element is at least partially or completely arch-shaped and wherein the at least one reinforcing element is connected to the plastic wall in the connection region in an integrally bonded manner.

6. The fuel tank of claim 2, wherein the at least one reinforcing element is an injection-molded component with ribbing.

7. The fuel tank of claim 2, wherein the at least one reinforcing element is connected on three sides to the plastic wall and wherein an end face and two side flanks that adjoin the end face and face away from one another are integrally bonded to the plastic wall.

8. The fuel tank of claim 2, further comprising a form-fitting connection that is formed between the at least one reinforcing element and the plastic wall by an undercut.

9. The fuel tank of claim 2, wherein the at least one reinforcing element comprises HDPE.

10. The fuel tank of claim 2, wherein the at least one reinforcing element is embedded in a recess or depression in the plastic wall.

11. A method for producing the fuel tank of claim 2, the method comprising the following method steps: producing the plastic wall that delimits the storage volume for storing the fuel by introducing the plasticized plastic into a molding tool and connecting one or more of the reinforcing elements to the plastic wall, the reinforcing elements being arranged on the molding tool before the plasticized plastic is introduced into the molding tool in such a way that at least one reinforcing element is connected to an outer side of the plastic wall that faces away from the storage volume, wherein the maximum thickness of the at least one reinforcing element normal to the wall corresponds to the multiple of the wall thickness of the plastic wall.

12. The method of claim 11, wherein the molding tool is a blow mold and wherein the at least one reinforcing element is connected to the plastic wall in an integrally bonded and/or form-fitting manner by blowing over said at least one reinforcing element within the blow mold.

13. The method of claim 11, wherein the at least one reinforcing element comprises a plurality of welding pins or welding ridges on an end face or on a side flank that adjoins the end face in order to form an integral bond to the plastic wall when the plasticized plastic is introduced into the molding tool, the welding ridges being distributed in a grid-like manner or the welding pins-being provided in a punctiform manner in rows and columns at a connection region; and/or wherein the at least one reinforcing element has a groove, an undercut, or a projection in order to provide a form-fitting connection to the plastic wall when the plasticized plastic is introduced into the molding tool.

14. The method of claim 11, wherein at least one reinforcing element is connected to the plastic wall on three sides, wherein an end face and two side flanks, which adjoin the end face and face away from one another, are integrally bonded to the plastic wall, the at least one reinforcing element, before the plasticized plastic is introduced, being seated on a mandrel or ridge of the molding tool, which protrudes into the reinforcing element and is bordered on two sides by the side flanks and is at least partially delimited from a mold cavity of the mold.

15. The method of claim 11, wherein at least one reinforcing element is connected to the plastic wall on three sides, wherein an end face and two side flanks, which adjoin the end face and face away from one another, are integrally bonded to the plastic wall, wherein the at least one reinforcing element, before the plasticized plastic is introduced, is received between two mold inserts, and wherein the mold inserts at least partially delimit the reinforcing element from a mold cavity of the molding tool.

16. The method of claim 11, wherein the at least one reinforcing element is fixed on the molding tool with a latching element during the introduction into the molding tool.

17. The fuel tank of claim 2, wherein the at least one reinforcing element comprises an end face and welding pins that are arranged on at least one of the end face and a side surface of the at least one reinforcing element that adjoins the end face.

18. The fuel tank of claim 2, wherein the at least one reinforcing element consists of HDPE.

19. The fuel tank of claim 2, further comprising a form-fitting connection that is formed between the at least one reinforcing element and the plastic wall by one groove.

20. The fuel tank of claim 2, wherein a height of the fuel tank measured between a tank top and a tank bottom of the fuel tank is thirty centimeters or more.

21. The fuel tank of claim 2, a plurality of reinforcing elements is provided on the plastic wall.

Description

(1) The plastic tank 2 has a plurality of reinforcing elements 8 for reinforcing the plastic wall 4. The reinforcing elements 8, of which only three are provided with a reference sign by way of example, are connected to an outer side 10 of the plastic wall 4 that faces away from the storage volume 6. A maximum thickness D1 of approx. 45 mm of the respective reinforcing elements 8, measured normal to the plastic wall 4, is greater than the wall thickness D2 of the plastic wall 4.

(2) The plastic wall 4 has a first half-shell 12 and a second half-shell 14. The half-shells 12, 14 are circumferentially welded along a weld seam 18 in the region of a side wall 16 of the plastic wall 4.

(3) The first half-shell 12 is an upper shell which comprises a tank top 20. The second half-shell 14 is a lower shell which comprises a tank bottom 22. A plurality of the reinforcing elements 8 are each arranged in an arch-shaped transition 24 from the side wall 16 to the tank top 20 or in an arch-shaped transition 26 from the side wall 16 to the tank bottom 22.

(4) FIGS. 3A and 3B show the reinforcing element 8 from FIGS. 1 and 2 individually in a perspective view from the front (FIG. 3A) and a perspective view from the rear (FIG. 3B).

(5) The reinforcing element 8 is tapered on two sides starting from a region 28 of maximum thickness D1 and has a substantially crescent-shaped or moon-shaped basic shape. An end connection region 30 with which the reinforcing element 8 is welded to the plastic wall at the end is arch-shaped. In the present case, the reinforcing element 8 is designed as an injection-molded component and has ribbing 32. A plurality of welding pins 34 are arranged in rows and columns on the end face 30 of the reinforcing element 8, which pins serve to establish an integral bond to the plastic wall 4.

(6) As an alternative or in addition to the punctiform welding pins, a grid-like or lattice-like ridge structure can be provided for establishing the integral bond according to further embodiments.

(7) As shown in FIG. 2, the reinforcing elements are each connected to the plastic wall 4 on three sides, with, on the one hand, the end face 30 and, in addition, two side flanks 31 which adjoin the end face 30 and face away from one another being integrally bonded to the plastic wall 4.

(8) Furthermore, grooves 36 are provided in the reinforcing element 8 in order to establish a form-fitting connection. The grooves 36 are molded into the side flanks 31 of the reinforcing element 8 and, like the welding pins 34, have been formed in one piece on the reinforcing element 8 by injection molding. The reinforcing elements 8 in the present case consist of HDPE.

(9) As can be seen from FIG. 2, the reinforcing elements 8 are embedded in the plastic wall 4, so that the reinforcing elements 8 each sit in a recess or depression in the plastic wall 4.

(10) A height H1 of the fuel tank 2 measured between the tank top and the tank bottom 22 is more than 30 cm in the present case.

(11) FIG. 4 shows a variant of a reinforcing element 38 for a fuel tank 2 according to the invention, which can be provided on the plastic wall 4 as an alternative or in addition to the reinforcing elements 8.

(12) The reinforcing element 38 differs from the previously described reinforcing element 8, which is provided with depressions 40 in the region of the side flanks, such that, in the state fastened to the wall 4, there are knob-like form-fitting connections to the plastic wall 4 of the fuel tank 2.

(13) These knob-like form-fitting connections are advantageous in that they are particularly suitable for absorbing a force between the fuel tank and the reinforcing element, as a result of which additional stiffening of the fuel tank can be effected.

(14) A depression 40 can preferably be designed as a through-hole, resulting in a form-fitting connection to the plastic wall 4 of the fuel tank 2 in the state fastened to the wall 4.

(15) Particularly preferably, a depression 40 with at least two different diameters can be formed. In particular, an advantageous embodiment is specifically conceived in which the larger diameter of the depression 40 is arranged on the designated side facing away from the wall 4, resulting in a form-fitting connection to the plastic wall 4 of the fuel tank 2 in the state fastened to the wall 4, which preferably has an undercut due to the different diameters of the depression 40.

(16) Such an undercut is particularly robust in the axial direction of the depression 40.

(17) A further advantage of a depression 40 designed as a through-hole is that it can be used as a vent during the blow molding process, so that the plasticized plastic can optimally penetrate into the depression 40 designed as a through-hole without counter pressure.

(18) Alternatively, welding pins or knobs or ridge structures can equally be provided in the region of the side flanks in order to promote a form-fitting connection and an integral bond to the plastic wall.

(19) FIG. 5 shows a further embodiment of a reinforcing element 42, which can be provided as an alternative or in addition to the reinforcing elements 8 and/or 38 on the liquid tank 2 according to the invention in order to reinforce the plastic wall 4.

(20) The reinforcing element 42 is characterized by tapered end portions 44 which have a thickness D3 of 5 mm or less over an end portion length L1. The end portion length L1 is approx. 20 mm.

(21) The reinforcing elements 38 and 42 also consist of HDPE in the present case.

(22) In order to produce a fuel tank according to the invention, a plurality of reinforcing elements 8, 38 and/or 42 are arranged in a molding tool 46 (FIG. 5).

(23) In the present case, the molding tool 46 is a blow mold, and so the reinforcing elements 8 and 38 shown are welded to the plastic wall when the plastic wall 4 is pressurized and molded within the blow mold 46. In the present case, the welding takes place from the shaping heat of a preform which has been extruded before the pressurization and introduction into the blow mold 46.

(24) In the present case, the reinforcing element 8 sits on a ridge 48 which protrudes into a rear receptacle 50 of the reinforcing element 8 (see FIG. 2), so that the reinforcing element 8 can be enclosed on three sides by the molded plastic wall 4 as shown in FIG. 2. Accordingly, the ridge 48 is bordered on two sides by the side flanks 31 of the reinforcing element 8 and is delimited from a mold cavity 52 of the molding tool 46.

(25) In contrast, the reinforcing element 38 (FIG. 6) is held between two mold inserts 54, of which only one mold insert 54 can be seen in the illustration shown. The mold inserts 54 border the reinforcing element 38 in portions on two sides opposite the mold cavity 52, so that the reinforcing element 38 is integrated into the plastic wall 4, as shown by way of example in FIG. 7.

(26) With reference to FIG. 8, different variants for the shaping of the end portions 44 are disclosed in the following. Variant a) shows an end portion 44 according to FIG. 5, which has simply been tapered with respect to an adjoining central middle portion of the relevant reinforcing element 42.

(27) FIG. 8 shows, in variant b), an embodiment of an end portion 44 which has a rounding in order to reduce the loads in the connection region to the plastic wall.

(28) According to variant c), FIG. 8 shows an end rounding that has been additionally widened.

(29) FIG. 8 shows, in variant d), an embodiment of the end portion 44 which is widened with respect to the adjoining central portion of the reinforcing element and which is also fork-shaped.

(30) FIG. 8 shows, in a variant e), an end portion 44 which has a through-opening or perforation.

(31) All of the aforementioned embodiments or variants of end portions 44 serve to reduce stress peaks in the connection region of the end portions to the wall.

(32) FIG. 9 shows a further variant of a reinforcing element 56 according to the invention in a perspective view from above (FIG. 9a) and a longitudinal section (FIG. 9b). The reinforcing element 56 differs from the variants disclosed above in that a plurality of through-openings 58 are formed in the reinforcing element 56, which openings are penetrated by the material of the plastic wall in the shaping heat of the plastic wall when connecting the reinforcing element 56 to a plastic wall, resulting in rivet-like connections between the relevant plastic wall and the reinforcing element 56 which are formed by the cooled material extending into an interior space of the reinforcing element 56 and engaging the through-opening 58 laterally from behind, so that form-fitting, non-destructively detachable connections are formed.

(33) FIGS. 10a, 10b and 10c show a further variant of a reinforcing element 60 according to the invention that differs from the variants disclosed above in that it is formed in a two-component design. The reinforcing element 60 has a first plastic component 62 and a second plastic component 64 which, as can be seen from the sectional views according to FIGS. 10b) and 10c), are interconnected in an integrally bonded and form-fitting manner.

(34) With reference to FIGS. 11a, 11b and 11c, types of connection between a reinforcing element and an associated plastic wall are shown, with the sectional view being selected analogously to the variant according to FIG. 2.

(35) FIG. 11a) shows, similarly to FIG. 2, a reinforcing element 66 which has form-fitting connections 68 and an integral bond 70 to an associated plastic wall 72.

(36) FIG. 11b) shows a reinforcing element 74 with a plastic wall 76, with lateral integral bonds 78 and an end integral bond 80 being formed between the reinforcing element 74 and the associated plastic wall 76.

(37) FIG. 11c) shows a variant of a connection between a reinforcing element 82 and an associated plastic wall 84, the reinforcing element 82 having welding pins 86 which are arranged at the end and also having welding pins 88 which are arranged in recesses 90.

(38) In this way, an integral bond 90 can be formed at the end and an integral bond and a form-fitting connection 94 can be formed laterally.

(39) FIG. 12 shows three variants of possible cross-sectional shapes of reinforcing elements, with variants a) and b) each showing trapezoidal cross sections of a reinforcing element 96 or 98 that is enclosed by a respectively associated wall 100, 102. According to FIG. 12c), a reinforcing element 104 is substantially rectangular in shape when viewed in cross section and enclosed on three sides by the associated wall 106.

(40) FIG. 13 shows a variant of a reinforcing element 8 in a central section, the reinforcing element 8 having a substantially triangular shape in the transverse direction.

(41) A plurality of grooves 36 are arranged on both sides of the wall of the reinforcing element 8, which grooves allow a form-fitting connection between the reinforcing element 8 and the designated fuel tank (not shown) connected to the reinforcing element 8.

(42) On the side facing away from the designated wall connected to the fuel tank, plastic components 64 are provided for stiffening the reinforcing element 8.

(43) A plurality of welding pins 34, which are also designed for connection to the fuel tank (not shown), are arranged on the upper side of the reinforcing element 8.

(44) FIG. 14 shows a reinforcing element 38 which likewise has a substantially triangular cross section in the longitudinal direction.

(45) In addition to the grooves 36 and the welding pins 34, the reinforcing element also has two blind holes 116 which are designed for being gripped by means of a gripper.

(46) The reinforcing element 38 can be securely gripped, positioned and released again by a gripper (not shown) by means of the blind holes 116.

(47) In particular, the reinforcing element 38 can be reproducibly positioned and optionally also fixed by a gripper (not shown) within a mold (not shown) by means of the blind holes 116.

(48) FIG. 15 shows a further reinforcing element 38 which, in addition to the grooves 36 and the welding pins 34, has a plurality of depressions 40, the depressions 40 being designed as through-holes.

(49) The depressions 40 allow a form-fitting connection to the designated fuel tank (not shown) and are also suitable as a vent, so that the plasticized plastic can optimally penetrate into the depressions 40 designed as a through-hole without counter pressure.

(50) FIG. 16a is a detailed view of a molding tool 46 with a latching element 110 in the form of an internal spring (not shown) with a pressure body (not separately identified) designed as a ball (not separately identified).

(51) The latching element 110 allows a reinforcing element 8 to be fixed in a simple and positionally precise manner within the molding tool 46.

(52) FIG. 16b shows a molding tool 46 having a latching element 110 as well as a reinforcing element 8 fixed with the latching element 110 on the molding tool 46.

REFERENCE SIGNS

(53) 2 Fuel tank 4 Plastic wall 6 Storage volume 8 Reinforcing element 10 Outer side 12 Half-shell 14 Half-shell 16 Side wall 18 Weld seam 20 Tank top 22 Tank bottom 24 Transition 26 Transition 28 Region 30 Connection region 32 Ribbing 34 Welding pin 31 Side flank 36 Groove 38 Reinforcing element 40 Depression 42 Reinforcing element 44 End portion 46 Molding tool 48 Ridge 50 Receptacle 52 Mold cavity 54 Mold insert 56 Reinforcing element 58 Through-opening 60 Reinforcing element 62 Plastic component 64 Plastic component 66 Reinforcing element 68 Form-fitting connections 68 and 70 Integral bond 72 Plastic wall 74 Reinforcing element 76 Plastic wall 78 Integral bonds 80 Integral bond 82 Reinforcing element 84 Plastic wall 86 Welding pins 88 Welding pins 90 Recesses 92 Integral bond 94 Form-fitting connection 96 Reinforcing element 98 Reinforcing element 100 Wall 102 Wall 104 Reinforcing element 106 Wall on three sides 110 Latching element 116 Blind hole H1 Height D1 Thickness D2 Wall thickness D3 Thickness