FUEL TANK FOR A MOTOR VEHICLE

Abstract

A fuel tank and a method for producing a fuel tank for a motor vehicle. The fuel tank is designed as a blow-molded hollow plastic member, into the interior of which a functional component support is introduced. The support, to which functional components, such as a fuel pump, a level indicator or valves can be secured, includes at least one supporting leg to be supported on an inner face of the hollow plastic member delimiting the interior thereof. The supporting leg of the functional component support is designed to include a connection point to which a functional component can be connected.

Claims

1. A fuel tank for a motor vehicle, which is designed as a blow-molded plastic hollow member, the fuel tank comprising: a functional component support arranged in an interior of the fuel tank, the functional component being adapted to have at least one functional component fasted thereto; and at least one supporting leg for providing support on an inner face that bounds the inner space of a plastic hollow member, the supporting leg of the functional component support being configured with a connection point to which the functional component is connected.

2. The fuel tank according to claim 1, wherein the functional component support is a baffle wall which divides the interior of the fuel tank and is supported by supporting legs on opposite sides on the interior of the fuel tank.

3. The fuel tank according to claim 1, wherein the supporting leg has a wall section with a contact surface, which is in contact with the interior of the fuel tank via a welded connection, and wherein a connection point of the functional component is arranged on a side of the wall section facing away from the contact surface.

4. The fuel tank according to claim 1, wherein the connection point for the functional component has at least one latching element which is adapted to be brought into latching engagement with a corresponding counter-contour on the functional component.

5. The fuel tank according to claim 3, wherein the connection point for the functional component is arranged in an assembly space, and wherein the assembly space is covered by the supporting leg wall section, which merges into a half-shell-shaped circumferential wall that is angled therefrom and surrounds the connection point and which is bounded on a bottom by a mounting base.

6. The fuel tank according to claim 5, wherein the assembly space has an access opening through which, during assembly, the functional component is inserted into the assembly space, and wherein the access opening is defined by an upper supporting leg wall section, the mounting base, and boundaries of the half-shell-shaped circumferential wall.

7. The fuel tank according to claim 6, wherein, during assembly in a first assembly step, the functional component is inserted in an assembly direction through the access opening into an assembly space, and wherein, in a second assembly step, is connected in the assembly direction to the connection point of the supporting leg.

8. The fuel tank according to claim 7, wherein the assembly space has an insertion section with a large access cross-section on its side facing away from the connection point, and wherein the insertion section of the assembly space merges into a positioning section with a reduced cross-section in a direction of the connection point, forming a positioning slope.

9. The fuel tank according to claim 1, wherein the functional component support is a separate pre-assembly unit, which is fitted with operating ventilation and/or refueling valves, and wherein, during the blow molding process, the functional component support is inserted into an interior of a tubular fuel tank preform made of thermoplastic resin, in an insertion direction along a hose longitudinal axis of the tubular fuel tank preform, and wherein the fuel tank preform is expanded to its final component contour in a blow molding process via blown air and under application of heat, and wherein, in order to reduce an insertion cross-section of the functional component support, the connection points for the operation ventilation and/or refueling valves and the supporting legs, as viewed in an insertion direction, are spaced apart from one another by a longitudinal distance.

10. The fuel tank according to claim 9, wherein the connection points, as viewed in the direction of insertion, are at least partly aligned one behind the other.

11. The fuel tank according to claim 9, wherein the functional component support has at least two strut arrangements, which are arranged spaced apart from each other in the insertion direction, and wherein each of the strut arrangements is supported transversely to the direction of insertion on opposite insides of the fuel tank by way of supporting legs.

12. The fuel tank according to claim 9, wherein the functional component support is inserted into the fuel tank preform via a retaining mandrel, and wherein the functional component support comprises at least one retaining mandrel passage opening through which the retaining mandrel is inserted up to a movement stop, and wherein the operating ventilation and/or refueling valves are positioned on the functional component support without or with a small transverse offset to the retaining mandrel.

13. The fuel tank according to claim 1, wherein functional component is a fuel pump, a level indicator, or a valve.

14. A method for producing a fuel tank according to claim 1, in which the functional component support is designed as a separate pre-assembly unit, which is fitted with operating ventilation and/or refueling valves, the method comprising: inserting the functional component support, in a blow molding process, into an interior of a tubular fuel tank preform made of thermoplastic resin, in an insertion direction along the tube longitudinal axis of the tubular fuel tank preform; expanding the fuel tank preform, in a blow molding process by means of blown air and by applying heat, to its final component contour in a blow molding tool; and spacing apart from one another by a longitudinal distance, in order to reduce an insertion cross-section of the functional component support, the connection points for the operating ventilation and/or refueling valves and the supporting legs as viewed in the direction of insertion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0028] FIG. 1 is a perspective view of a plastic fuel tank, in the interior of which a baffle acting as a functional component support is arranged;

[0029] FIG. 2 is a perspective detailed view of an upper supporting leg of the baffle with an as yet still disassembled venting valve;

[0030] FIG. 3 illustrates the supporting leg of the baffle with a venting valve mounted thereon; and

[0031] FIGS. 4 to 8 are respective views, each showing the process steps for producing the fuel tank shown in FIG. 1.

DETAILED DESCRIPTION

[0032] FIG. 1 is a perspective view of a fuel tank made from a thermoplastic resin, which is designed as a blow-molded plastic hollow member. In the interior of the fuel tank, an elongated baffle wall 1 is arranged, which divides the interior of the tank. The baffle wall 1 is also manufactured from a thermoplastic resin, for example in an injection-molding process. As can be seen from FIG. 1, a total of three mutually spaced vertical, columnar strut arrangements 3, which are supported in a vertical direction between the upper and lower fuel tank inner sides, are integrated in the baffle wall 1. For this purpose, each of the strut arrangements 3 of the baffle wall 1 has lower supporting legs 4 and upper supporting legs 5, which are supported on the respective fuel tank interior side, under the formation of node locations K. The node locations K are designed to be rigid to provide the fuel tank and the baffle wall 1 arranged therein with sufficient dimensional stability.

[0033] In FIG. 1, each of the upper supporting legs 5 of the strut arrangements 3 is formed with an additional connection point 7, in which functional components, such as a fuel pump or venting valves 8, 9, are connected. The venting valves 8, 9 are connected to a vent line 11, which can be guided outwards via a tank connector 15.

[0034] FIGS. 2 and 3 show the construction of one of the upper supporting legs 5. Accordingly, the supporting leg 5 has a plate-shaped wall section 17, on the upper side of which a knob-like structured contact surface 19 is formed. In the assembly position, the supporting leg wall section 17 is welded at its contact surface 19 to the fuel tank interior. In FIGS. 2 and 3, the connection point 7 has latching elements, the latching webs 21 of which are formed on the underside of the supporting leg wall section 17, facing away from the contact surface 19.

[0035] The latching webs 21 of the connection point 7 project vertically downwards into an assembly space 23. At their free lower ends, the latching webs 21 each have a latching lug 24, which, in the assembly position (FIG. 3), engage behind a corresponding counter-contour 25 on the housing 27 of the venting valve 9.

[0036] In FIGS. 2 and 3, the above-mentioned assembly space 23 is covered on the upper side by the supporting leg wall section 17, which merges into an angled, half-shell circumferential wall 29, which is arranged vertically and surrounds the connection point 7.

[0037] At the bottom, the assembly space 23 is bounded by a mounting base 31. Between the two vertically extending edges of the half-shell-shaped circumferential wall 29, an access opening 33 is defined, which extends in the vertical direction from the mounting base 31 to the lower side of the supporting leg wall section 17.

[0038] In the production of the fuel tank, firstly, the baffle wall 1 acting as a functional component support is fitted with the functional components 8, 9, under formation of a pre-assembly unit, which is separate from the fuel tank. The fitted baffle wall 1 is then inserted into the interior of a tubular fuel tank preform made of plastic. Subsequently, a blowing operation is carried out in which the preform is expanded into the final tank outer contour and, at the same time, the upper and lower supporting legs 4, 5 of the baffle wall are also welded at their contact surfaces 19 to the material of the plastic tank wall.

[0039] The assembly process is illustrated in FIGS. 2 and 3, in which the venting valve 9 is connected to the connection point 7 of the upper supporting leg 5. Accordingly, in a first assembly step, the venting valve 9 is inserted into the assembly space 23 through the access opening 33 in an insertion direction I (FIG. 2), and is pre-positioned there on the mounting base 31. Subsequently, in a second assembly step, the already pre-positioned venting valve 9 is displaced vertically upwards in an assembly direction II and locked with the connection point 7, as shown in FIG. 3. As a result of the latching process, a clicking sound is produced which confirms, as an acoustic feedback signal, a perfect connection of the venting valve 9 to the supporting leg 5. According to FIG. 3, the venting valve 9 is fastened in the locked state at a distance from the mounting base 31, on the underside of the supporting leg wall section 17.

[0040] For ease of assembly, the assembly space 23 has, on its side facing away from the connection point 7, an insertion section 35 with a large access cross-section, which allows for a simple pre-positioning of the venting valve 9 in the assembly space 23. The insertion section 35 of the assembly space 23 merges into an upper positioning section 39, in the upward direction to the connection point 7, to form a positioning slope 31, which has a reduced cross-section as compared to the insertion section 35. Due to the cross-section tapering, a precisely positioned alignment is made in the second assembly step (i.e., when the venting valve 9 is displaced onto the latching elements of the connection point 7) in the assembly direction II upwards.

[0041] The upper supporting legs 5 of the strut arrangements 3 shown in FIG. 1 are essentially identical to the supporting leg 5 shown in detail in FIGS. 2 and 3, but, if appropriate, are conformed to the respective functional component to be integrated therein.

[0042] Below, FIGS. 4 to 8 describe the basic process steps for the production of the fuel tank shown in FIG. 1: according to FIG. 4, initially, a tubular fuel tank preform 41 made of a thermoplastic resin is provided, the inner wall of which defines a free cross-section q.sub.i. The preassembled functional component support 1 is inserted (FIG. 5) into the interior of the tubular fuel tank preform 41 in an insertion direction E along a longitudinal axis S. In FIG. 5, the fuel tank preform 41 with the functional component support 1 inserted therein is located between two mold halves of a blow molding tool 43. This is closed for carrying out a blow molding operation. Blown air is then introduced into the preform 41, as a result of which the preform 41 is expanded under application of internal pressure and heat to its final component contour (FIG. 6).

[0043] As can be seen in FIG. 4, the operating ventilation and refueling valves 8, 9, 10 as well as the supporting legs 4, 5 are arranged one behind the other at longitudinal intervals a, as viewed in the direction of insertion E. In addition, the two operating ventilation valves 8, 9 are arranged one after the other, as viewed in the direction of insertion E, while the middle refueling valve 10 is offset only laterally outwards by a small transverse displacement. Overall, an insertion cross-section q, which is substantially smaller than the interior cross-section q.sub.i provided by the tubular fuel tank preform 41, is thus obtained. As a result, a process-reliable insertion movement of the functional component support 1 is achieved in a simple manner without collision with the preform inner wall.

[0044] The insertion operation is performed according to FIG. 4 or 7 by means of a retaining mandrel 45. As can be seen in FIG. 7, the rod-shaped retaining mandrel 45 is inserted through passage openings 47 of the functional component support 1 up to a movement stop 49, which is located upstream in the insertion direction E. As shown in FIG. 8, the operating ventilation and refueling valves 8, 9, 10 are positioned on the functional component support 1, without or with only a small transverse offset to the retaining mandrel 45, in order to further reduce the insertion cross-section q.sub.F.

[0045] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.