Fuel tank made of thermoplastic material

Abstract

Fuel tank made of thermoplastic material comprising baffle components provided therein in the form of at least one baffle element (2) comprising at least one wall portion (4) which is clamped approximately centrally and/or at the end, so that said wall portion may perform relative movements in relation to the tank, caused by splashing movements of the fuel, at least one fastening foot being provided for the clamping, the base thereof being provided with at least one through-hole, through which the fastening foot is riveted and/or welded to the tank wall (2).

Claims

1. A fuel tank for a motor vehicle comprising: at least one baffle element within a volume of the fuel tank, wherein the fuel tank is a thermoplastic fuel tank, the at least one baffle element comprising a wall portion retained to a wall of the fuel tank by a fastening foot, wherein, when fuel is in the fuel tank, the wall portion deforms in response to movements of the fuel in the fuel tank, wherein the fastening foot comprises at least one through-hole used to fasten the fastening foot to the wall of the fuel tank, wherein the at least one baffle element is configured such that, in its entirety, the at least one baffle element extends only over one part of an inside height and only over one part of an inside width of the volume of the fuel tank, wherein the wall portion is formed of thermoplastic material, wherein the fastening foot is formed of thermoplastic material, and wherein the fastening foot has a greater bending stiffness than the wall portion.

2. The fuel tank according to claim 1, wherein: the wall portion comprises a flexible wing which elastically deforms in response to the movements of the fuel in the fuel tank, and a region of retention which is retained by the fastening foot.

3. The fuel tank according to claim 1, wherein: when the fuel is in the fuel tank, the thermoplastic material of the fastening foot is exposed to the fuel within the fuel tank.

4. The fuel tank according to claim 1, wherein: the fastening foot is fastened to a region of an inner side of the wall of the fuel tank, and when the fuel is in the fuel tank, the inner side of the wall of the fuel tank is exposed to the fuel.

5. The fuel tank according to claim 1, wherein: the fastening foot is welded and/or riveted to the wall of the fuel tank.

6. The fuel tank according to claim 1, wherein: the fastening foot is riveted to the wall of the fuel tank through the at least one through-hole.

7. The fuel tank according to claim 1, wherein: the fastening foot is welded to the wall of the fuel tank through the at least one through-hole.

8. The fuel tank according to claim 1, wherein: the wall portion and the fastening foot are fastened directly to each other.

9. The fuel tank according to claim 1, wherein: the wall portion and the fastening foot form a latching connection.

10. The fuel tank according to claim 1, wherein: the wall portion is disposed in a clamp of the fastening foot.

11. The fuel tank according to claim 1, wherein: the wall portion is latched to the at least one fastening foot.

12. The fuel tank according to claim 1, wherein: the at least one through-hole is used to rivet and/or weld the fastening foot to the wall of the fuel tank.

13. The fuel tank according to claim 1, wherein: the at least one through-hole is occupied by thermoplastic material of the fuel tank.

14. The fuel tank according to claim 13, wherein: the thermoplastic material of the fuel tank is from the wall of the fuel tank.

15. The fuel tank according to claim 13, wherein: the thermoplastic material of the fuel tank forms a head to retain the fastening foot to the wall of the fuel tank.

16. The fuel tank according to claim 1, wherein: the at least one through-hole is occupied by a pin fastened to the wall of the fuel tank.

17. The fuel tank according to claim 1, wherein: the at least one through-hole is occupied by a material composition which is compatible with thermoplastic material of the wall of the fuel tank with respect to welding.

18. The fuel tank according to claim 1, wherein: the wall portion, in an installed position of the fuel tank in the motor vehicle extends approximately transversely to a direction of movement of fuel in the fuel tank.

19. The fuel tank according to claim 1, wherein: the at least one through-hole of the fastening foot comprises a plurality of through-holes, and the plurality of through-holes are each used to fasten the fastening foot to the wall of the fuel tank.

20. The fuel tank according to claim 1, wherein: the at least one baffle element comprises a plurality of baffle elements, with each baffle element of the plurality of baffle elements comprising a wall portion retained to the wall of the tank by a fastening foot, respectively.

Description

(1) The invention is described hereinafter with reference to an exemplary embodiment shown in the drawings, in which:

(2) FIG. 1 shows a cross section through a fuel tank according to the invention,

(3) FIG. 2 shows a section along the lines II-II in FIG. 1,

(4) FIG. 3 shows a side view of a baffle element,

(5) FIG. 4 shows a plan view tilted by 90° of the baffle element shown in FIG. 3,

(6) FIG. 5 shows the view of a front face of the baffle element shown in FIG. 3,

(7) FIG. 6 shows a view corresponding to FIG. 3 of the side of the baffle element concealed in FIG. 3,

(8) FIGS. 7a & 7b show an exploded view of the fastening element with the wall portion to be fastened thereto and

(9) FIGS. 8 & 9 show schematic views which illustrate the fastening of the fastening foot to the tank wall.

(10) The fuel tank 1 shown in FIG. 1 comprises the conventional functional components for operating a fuel tank, such as the filling state sensor, de-aerating valves and venting valves, a conveyor unit with fuel pump, etc. Moreover, said fuel tank comprises a filler pipe and other tank interfaces which are not shown for reasons of simplicity. In the fuel tank 1, baffle components in the form of baffle elements 2 are arranged which are connected by a material and/or positive connection to the lower tank wall 3 in the installed position. Within the scope of the invention, the baffle elements 2 may also be connected to the upper tank wall in the installed position.

(11) The baffle elements 2 are, for example, arranged in several rows offset relative to one another inside the fuel tank 1, as shown in FIG. 2. Said baffle elements have been introduced into the tank during and/or directly after the moulding of the fuel tank 1. The position and arrangement thereof is freely selected, irrespective of any inspection openings in the fuel tank 1.

(12) The production of the fuel tank 1 according to the invention takes place by extrusion blow-moulding of web-like or sheet-like preforms which either have been obtained by cutting off an extruded tube or by extruding a thermoplastic material through sheet dies. The extrudate and thus also the tank wall 3 of the multi-layered fuel tank 1 consist of a six-layered co-extrudate based on HDPE with at least one barrier layer for hydrocarbons.

(13) The web-like or sheet-like preforms are moulded inside a three-part moulding tool comprising two outer moulds, in each case comprising a cavity and a central tool to form a plastics hollow body. In this case, initially the web-like preforms are moved into the multi-part, open tool, and namely between the outer moulds and a central mould arranged therebetween and/or a central tool arranged therebetween. The outer moulds describe in each case a part of the contour of the product and form together a closed mould cavity. Initially, the outer moulds are closed against the central tool with the interposition of the preforms and then the preforms by the application of differential pressure are placed against the cavities of the blow-moulding tools. Via the central tool which, for example, may comprise component carriers and other devices, insert parts such as for example the aforementioned baffle elements 2 are fastened to the tank walls moulded in the cavities, and namely preferably by utilizing the extrusion heat of the still hot melt material and/or melt heat of the tank wall.

(14) The advantages of this production method result, in particular, in combination with the baffle elements 2 according to the invention. This production method permits a fastening of the baffle elements 2 to at least one tank wall in any suitable layout, as is described below in more detail.

(15) At this point it should be mentioned that the baffle elements 2 naturally are also arranged on opposing tank walls 3, so that said baffle elements protrude alternately from the top and from the bottom into the tank volume.

(16) Each baffle element 2 comprises a substantially flexible wall portion 4 and a fastening foot 5, which may both consist of thermoplastic material, for example an HDPE.

(17) In the exemplary embodiment shown, the fastening foot 5 is latched approximately centrally to the wall portion 4, so that said wall portion in the installed position forms a central clamping of the baffle element. The fastening foot 5 preferably consists of a thermoplastic material which has a greater bending stiffness than the wall portion 4 which, as will be described in more detail below, forms a flexible paddle. The greater bending stiffness of the fastening foot 5 may either be achieved via the type of material or via the material thickness.

(18) The fastening foot 5 has a base 6 which is provided with through-holes 7. Some of these through-holes 7 are configured as funnel-shaped bores 7a, whereas other through-holes are configured as rectangular apertures 7b.

(19) As is visible, for example, from FIGS. 8 and 9, the base 6 of the fastening foot 5 during the introduction of the baffle elements 2 in the fuel tank 1 is applied by pressure onto the still hot melt material of the tank wall 3, so that the inner layer 8 of the tank wall 3 is driven through the through-holes 7a, 7b, and at least in the region of the bores 7a undergoes a widening in the manner of a rivet head. This swelling of the material such that the bores 7a are engaged from behind, may either be promoted by the contour of the bores 7a or be produced by a tool during production, similar to the production of a conventional rivet connection. The material of the rivets thus formed is completely driven through from the inner layer 8 of the tank wall 3. As already mentioned above, instead of such riveting in situ, riveting by means of prefabricated rivets made of thermoplastic material may also be provided.

(20) As may be derived, in particular, from FIGS. 3 and 4 in combination with FIG. 7, the baffle elements 2 are configured in two parts, the flexible wall portion 4 being latched and/or clipped via latching connections 10 to a support surface 11 of the fastening foot 5 extending approximately perpendicular to the base 6. In the installed position, the fastening foot 5 forms a central clamping of the flexible wall portion 4, the free ends 12 thereof being able to be deflected through the movement of the splashing fuel, as shown by way of indication by the arrows in FIG. 2, relative to the fixedly arranged fastening foot 5. The baffle elements 2 and the fastening foot 5 may naturally also be configured integrally/in one piece.

(21) By “flexible” in the meaning of the invention is understood that the length and wall thickness and the nature of the material of the wall portions 4 of the baffle elements 2 are dimensioned so that the free ends 12 of the wall portions 4 may be deflected by the energy of the splashing fuel, so that the splashing movements of the fuel are converted into deformation energy of the wall portions 4.

LIST OF REFERENCE NUMERALS

(22) 1 Fuel tank 2 Baffle elements 3 Tank wall 4 Wall portion 5 Fastening foot 6 Base 7 Through-holes 7a Bores 7b Aperture 8 Inner layer 9 Rivets 10 Latching connection 11 Support surface 12 Ends