Fuel tank for a motor vehicle

Abstract

Fuel tank (1) for a motor vehicle, designed as a plastic container, in the interior of which at least one functional part (7) is arranged, which is connected at a connection point (A) on the inside to the plastic material of a plastic container wall (3), wherein the connection point (A) has a mounting recess (5) formed in the plastic container wall (3) projecting from the inside out, wherein the mounting recess (5) has a closed mounting base (13) from which a side wall (11) of the mounting recess (5) is raised, which transitions into the plastic container wall (3) on the inside of the container, characterized by the fact that The connection point (A) has an expansion anchor (9) formed on the functional part (7), which projects into the mounting recess (5) and is pressed into a side wall (11) of the mounting recess (5) by displacing plastic material, wherein the expansion anchor (9) of the functional part (7) has at least one adjustable expansion segment (17) which can be adjusted between a rest position, in which the expansion anchor (9) has a cross-sectionally reduced mounting cross-section (Q) M ) exhibits, and a spreading position in which the spreading anchor (9) has an expanded spreading cross-section (Q S ) is adjustable, wherein the spreading segment (17) has on its side facing the side wall (11) of the mounting recess (5) a form-fitting contour (19) that can be pressed into the plastic material, by means of which the connection strength at the connection point (A) is increased.

Description

[0001] The invention relates to a fuel tank for a motor vehicle according to the preamble of claim 1.

[0002] Such a fuel tank can be made of a thermoplastic material, for example, by extrusion blow molding or injection molding. Functional components of the fuel system can be housed inside such a fuel tank, thus reducing the space required outside the tank and also decreasing the number of necessary tank openings, which is advantageous with regard to emissions from the fuel tank. Examples of functional components that can be mounted inside the fuel tank include a fuel pump, a level sensor, or various valves.

[0003] DE 10 2010 032 279 B4 discloses a fuel tank of this type, which is manufactured, for example, by extrusion blow molding. On the inside of the plastic tank, a mounting base for a functional component is attached at a connection point using rivet pins made of thermoplastic material, prefabricated by injection molding. These rivet pins are welded to the inside of the plastic tank wall, which is still hot and molten during the manufacturing process. DE 10 2012 020 949 B4 discloses another fuel tank, which is also manufactured by extrusion blow molding. During the manufacturing process, a metal liner is pressed into the hot and molten plastic material of the plastic tank.

[0004] DE 30 05 535 A1 discloses an arrangement for attaching a container fitting to a plastic fuel tank for motor vehicles, which is provided with an outwardly directed pipe socket formed in the tank wall, through which the fitting is inserted and attached to the fuel tank with fastening means, wherein at least one fastening means is formed by a sleeve made of an elastic material, e.g. plastic or rubber, and is clamped between the fitting and the pipe socket, wherein the inner end section of the sleeve surrounds the fitting by means of an inner clamping device or the like and the outer end section of the sleeve surrounds the pipe socket by means of an outer clamping device or the like.

[0005] DE 10 2015 210 412 A1 describes a fuel tank comprising: a hollow body; a valve device that is received in the hollow body; and a support element designed to support the valve device and to be attached to the upper wall of the hollow body. The support element is provided with coupling teeth that engage in the corresponding undercut seating surfaces provided in the relief parts of the upper wall.The coupling teeth have a first rigid coupling tooth designed for engagement with a first seat surface, and second elastically deformable coupling teeth designed for engagement with the corresponding second seats surfaces, such that the first coupling tooth, after engaging with the first seat surface, acts as a pivot point around which the arrangement formed by the support element and the valve device can rotate, being pressed against the upper wall, so that each of the second coupling teeth engages in the corresponding second seat surface.

[0006] A hollow body comprising an accessory module attached to its wall, which is inserted into a guide formed in the wall, is shown in US 2011 / 0 101 006 A1. The module consists of a housing and two flat, flexible wings extending in opposite directions from the housing. Their distant edges are substantially parallel and are inserted into opposing grooves in the guide. The module also includes at least one flexible lamella extending from the housing. This lamella is shaped such that it bends elastically when the module is inserted into the guide, and its end, when undistorted, faces a stop in the guide and extends beyond the end of the guide in the sliding direction.

[0007] According to the method described in US 2011 / 0 140 314 A1 for joining a component to a molded part, the process may involve positioning the component near a wall of the article to be molded, with a portion of the component overlapping a portion of the article wall while the wall is still at least partially molten. The article wall is then cooled while the overlapped portion of the component remains covered by the wall. Preferably, a portion of the component overlaps the article wall on two sides to hold the component firmly in position after the article has been molded. The article may be a container or any other object, as desired.

[0008] EP 2 946 905 A1 proposes a method for attaching an accessory inside a blow-molded tank. The tank has a plastic wall made from a preform, and the accessory comprises a body with at least one radially projecting attachment section. The method comprises the following steps: a) Placing the accessory and the preform in a molten state into a mold such that the accessory is surrounded by the preform. The mold has cavities, at least one of which is equipped with at least one movable insert configured to fold over a portion of the molten preform locally at the attachment point; b) Contacting the preform with the fastening section; c) Moving the insert forward and locally folding over part of the molten preform at the fastening section; d) Closing the mold by moving the mold cavities into a final closed position and inflating the preform to form the blow-molded tank; e) Moving the stake back; and f) Opening the mold.

[0009] EP 2 946 906 A1 proposes a method for attaching an accessory inside a blow-molded tank. The tank has a plastic wall made from a preform, and the accessory comprises a body with at least one radially projecting attachment section. The method comprises the following steps: a) Placing the accessory and the preform in a molten state into a mold such that the accessory is surrounded by the preform. The mold has cavities, at least one of which is equipped with at least one movable insert configured to locally fold over a portion of the molten preform at the attachment point; b) Contacting the preform with the fastening section; c) Moving the insert forward and locally folding over part of the molten preform at the fastening section; d) Closing the mold by moving the mold cavities into a final closed position and inflating the preform to form the blow-molded tank; e) Moving the stake back; and f) Opening the mold.

[0010] DE 103 24 581 B3 discloses an expansion rivet with a rivet head on the underside of which several resiliently formed expansion legs are provided, and with an expansion mandrel that can be moved from a starting position through a through-hole in the rivet head between the expansion legs, thereby expanding them into an assembly position. The expansion rivet is characterized by a manually accessible actuating device for manually retracting the expansion mandrel from the assembly position to the starting position.

[0011] The object of the invention is to provide a fuel tank for a motor vehicle in which a functional part can be attached to the inside of the fuel tank in a simple and reliable manner.

[0012] The problem is solved by the features of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims.

[0013] According to the invention, the connection point has an expansion anchor formed on the functional part, which projects into the mounting recess and is pressed into a side wall of the mounting recess by displacing plastic material, wherein the expansion anchor of the functional part has at least one adjustable expansion segment which is adjustable between a rest position, in which the expansion anchor has a reduced cross-section, and an expansion position, in which the expansion anchor has an expanded expansion cross-section, wherein the expansion segment has a form-fitting contour on its side facing the side wall of the mounting recess that can be pressed into the plastic material, by means of which the connection strength at the connection point is increased.

[0014] In this way, the integration of the functional part into the interior of the container can be achieved not only through material bonding but also through form-fitting. For both form-fitting and material-fitting connections, no slider in the mold is required to create undercuts for the fastening elements. Instead, the functional part itself provides a locking or form-fitting connection. Here, the connection to the inner wall of the plastic container (for example, by means of a blow-molded or injection-molded part) is established solely through the action of the connecting element or mechanism located in the functional part. This eliminates the need for sliders in the mold. Furthermore, a purely material-fitting connection is avoided. For the connection according to the invention, a translational, rotational, or combined movement can be considered.What is relevant is solely the creation of an undercut in the plastic material by the functional part to be inserted.

[0015] Further aspects of the invention are described below: In the expansion segment rest position, the expansion anchor, particularly with some assembly play, can be easily inserted into the mounting recess. In contrast, in the expansion segment expansion position, the expansion anchor can be pressed into the side wall of the mounting recess by displacing plastic material.

[0016] In one technical implementation, the expansion anchor can have a preferably linearly adjustable base body. The expansion segment can be pivotally mounted to the expansion anchor base body about a pivot axis. The expansion segment can thus be adjusted between its rest position and its expanded position in a pivoting movement. During a connection process, the functional part with its expansion anchor can be inserted into the mounting recess in one assembly direction. To reliably achieve a sound connection, it is preferred to keep at least the plastic container wall in a molten state during the connection process.

[0017] The spreading segment can have a wedge-shaped contact surface that interacts with a linearly adjustable spreading cone. Thus, by means of a further linear adjustment, the spreading cone can also be adjusted against the wedge-shaped contact surface of the spreading segment, thereby moving the spreading segment into its expanded position, in which the expanding anchor is expanded up to the expansion cross-section.

[0018] The advantageous embodiments and / or further developments of the invention described above and / or described in the dependent claims can be used individually or in any combination with each other, except, for example, in cases of clear dependencies or incompatible alternatives.

[0019] They show: Fig. 1 a connection point between the functional part and a plastic container wall of the fuel tank; Fig. 2 to 4 enlarged partial views illustrating the process steps for attaching the functional part to the plastic container wall of the fuel tank.

[0020] In the Fig. Figure 1 shows a completed connection point A between a plastic container wall 3 of a fuel tank 1 and a functional part 7 located inside the tank. Accordingly, the connection point A consists of a mounting recess 5 formed in the plastic container wall 3, projecting from the inside out, and an expansion anchor 9 formed on the functional part 7. The expansion anchor 9 of the functional part 7 projects into the mounting recess 5 and is pressed into a side wall 11 that delimits the mounting recess 5, displacing plastic material. The mounting recess 5 has in the Fig. 1. A closed mounting base 13 is provided, from which the surrounding side wall 11 is raised, transitioning into the plastic container wall 3 at an inner opening. The mounting recess 5 is located in the Fig. 1. Designed in an approximately hollow cylindrical shape.

[0021] As from the Fig. As further shown in Figure 1, the expansion anchor 9 has a base body 15 which is rigidly attached to the functional part 7. Two opposing (or more) expansion segments 17 are pivotally mounted to the base body 15 about a pivot axis S. In the Fig. 1. The spreading segments 17 are pivoted outwards into a spreading position, giving the spreading anchor 9 an expanded spreading cross-section Q. S ( Fig. 4) assumes a position in which its spreading segments 17 are pressed into the plastic material of the mounting recess side wall 11. To increase the bond strength, the two spreading segments 17 each have form-fitting contours 19 on their sides facing the mounting recess side wall 11, which are pressed into the plastic material.

[0022] The following will be based on the Fig. Sections 2 to 4 describe the process for attaching the functional part 7 to the plastic container wall 3. The attachment process is integrated into a method for manufacturing a fuel tank, as is known, for example, from DE 10 2010 032 279 B4 or DE 10 2012 020 949 B4 and is common practice. Accordingly, two web-shaped preforms are provided in a continuous extrusion process and extruded between open mold halves of a blow mold. The mold halves are located in the Fig. Figures 2 to 4 indicate a tool half 20. In a further process step, the tool halves are closed against a tool divider arranged between them, with the preforms inserted between them. Subsequently, the preforms are placed into the cavities of the tool halves 1 using vacuum and / or overpressure and formed into two complementary shell-shaped semi-finished products, utilizing the extrusion heat of the preforms. Before the still molten or warm-plastic shell-shaped semi-finished products are assembled to form the fuel tank, the functional part 7 is attached to the inside of the plastic container wall 3 at the connection point A.

[0023] This is done according to the Fig. 2. First, the mounting recess 5 is formed in the plastic container wall 3 using the blow molding process. Subsequently, a functional part carrier 21, which supports the functional part 7, is moved into a position where the expansion anchor 9 is approximately aligned with the hollow cylindrical mounting recess 5. As can be seen from the Fig. As can be seen from Figure 2, the two expansion segments 17 are still adjusted radially inwards into the rest position, in which the expansion anchor 9 has a reduced cross-sectional mounting cross-section Q. M ( Fig. 2) occupies. This allows, as a result of a linear stroke movement I ( Fig. 2) by means of a first actuating element 23 of the functional part carrier 21, the expansion anchor 9 can be easily inserted into the mounting recess 5 with an assembly clearance.

[0024] As can be seen from the figures, each of the spreading segments 17 has a wedge-shaped contact surface 25 on its inner side, which interacts with a linearly adjustable spreading cone 27. The spreading cone 27 can also be adjusted linearly by means of a second actuator 29, whereby the two spreading segments 17 pivot outwards about the pivot axes S into their spread position ( Fig. 4) be adjusted. In which the expansion anchor 9 expands the expanded expansion cross-section Q S This results in the form-fitting contours 19 of the two spreading segments 17 being pressed into the plastic material of the mounting recess side wall 11 in a form-fitting and material-locking manner. The one in the Fig. The bonding process shown in steps 2 to 4 takes place with the plastic material still molten or warm-plastic. Reference symbol list 1 fuel tank 3 plastic container wall 5 Mounting recess 7 Functional part 9 expansion anchors 11 Side wall 13 Mounting floor 15 expansion anchor base bodies 17 spreading segments 19 interlocking contours 20 tool half 21 functional part carriers 23 first actuator 25 approach area 27 Spreading cone 29 second actuator A connection point Q S expanded spreading cross-section Q M Reduced cross-section mounting cross-section S swivel axis

Claims

[1] Fuel tank (1) for a motor vehicle, which is designed as a plastic container in the interior of which at least one functional part (7) is arranged, which is connected at a connection point (A) on the inside to the plastic material of a plastic container wall (3), wherein the connection point (A) has a mounting recess (5) formed in the plastic container wall (3) projecting from the inside out, wherein the mounting recess (5) has a closed mounting base (13) from which a side wall (11) of the mounting recess (5) is raised, which transitions into the plastic container wall (3) on the inside of the container, characterized by , that The connection point (A) has an expansion anchor (9) formed on the functional part (7), which projects into the mounting recess (5) and is pressed into a side wall (11) of the mounting recess (5) by displacing plastic material, wherein the expansion anchor (9) of the functional part (7) has at least one adjustable expansion segment (17) which can be adjusted between a rest position, in which the expansion anchor (9) has a cross-sectionally reduced mounting cross-section (Q) M ) exhibits, and a spreading position in which the spreading anchor (9) has an expanded spreading cross-section (Q S ) is adjustable, wherein the spreading segment (17) has on its side facing the side wall (11) of the mounting recess (5) a form-fitting contour (19) that can be pressed into the plastic material, by means of which the connection strength at the connection point (A) is increased. [2] Fuel tank (1) according to claim 1, characterized by, that in the rest position of the expansion segment (17) the expansion anchor (9) can be inserted into the mounting recess (5), in particular with a mounting clearance, and that in the expansion position of the expansion segment (17) the expansion anchor (9) is pressed into the side wall (11) of the mounting recess (5). [3] Fuel tank (1) according to claim 1 or 2, characterized by , that the expansion anchor (9) has a base body (15) that is particularly linearly adjustable in stroke, to which the expansion segment (17) is pivotably articulated about a pivot axis (S), and that the expansion segment (17) is pivotally articulated between the mounting cross-section (Q) M ) and the spreading cross-section (Q S ) is adjustable, and / or that the expanding anchor (9) of the functional part (7) can be inserted into the mounting recess (5) with a first linear stroke movement (I). [4] Fuel tank (1) according to claim 3, characterized by, that the spreading segment (17) has a wedge-shaped approach surface (25) which interacts with a linearly stroke-adjustable spreading cone (27), and that during a second linear stroke adjustment (II), the spreading cone (27) moves the spreading segment (17) from its rest position to its spreading position, in which the spreading anchor (9) expands the spread cross-section (Q) S ) exhibits. [5] Fuel tank (1) according to any of the preceding claims, characterized by , that during the connection of the functional part (7) to the plastic container, at least the plastic material of the plastic container wall (3) is in a molten state.

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