Operating fluid tank

Abstract

The invention relates to an operating fluid tank (1) for a motor vehicle, comprising a tank body which is composed of two mutually complementary, injection-molded shells (2) which are made of thermoplastic material and which are welded circumferentially to one another to form a substantially closed hollow body, wherein at least one shell (2a, 2b) is formed at least in certain regions from thermoplastic materials of differing strength and/or elasticity, wherein at least one partial region is formed from a thermoplastic material which is elastically deformable, and wherein the shell (2a, 2b) has been obtained by a co-injection process during injection molding.

Claims

1. An operating fluid tank for a motor vehicle, comprising: a tank body having at least two mutually complementary shells of thermoplastic material, wherein the shells are welded circumferentially to one another to form a substantially closed hollow body, wherein at least one shell of the shells is a multilayered shell and comprises at least a first layer having at least one region formed of a first thermoplastic material and another region formed of a second thermoplastic material, wherein the first layer is an outer layer of the at least one multilayered shell, wherein the second thermoplastic material has a greater strength than the first thermoplastic material, wherein the first thermoplastic material is elastically deformable, wherein the at least one region formed of the first thermoplastic material provides a deformation region which is bordered by the region formed of the second thermoplastic material, wherein the deformation region elastically deforms in response to a pressure rise within the fluid tank to prevent plastic deformation of the region formed of the second thermoplastic material.

2. The operating fluid tank as claimed in claim 1, wherein the elastically deformable first thermoplastic material is formed of a thermoplastic elastomer.

3. The operating fluid tank as claimed in claim 1, further comprising at least one integrally attached functional installation part and/or at least one add-on part made of thermoplastic material.

4. The operating fluid tank as claimed in claim 3, further comprising a plurality of integrally attached retaining lugs made of thermoplastic material.

5. The operating fluid tank as claimed in claim 3, wherein the functional installation part comprises at least one elastically deformable baffle.

6. The operating fluid tank as claimed in claim 3, wherein at least one valve body for a filling venting valve or an operational venting valve is provided as the functional installation part.

7. The operating fluid tank as claimed in claim 1, wherein at least one shell has at least one filler pipe or at least one filler neck made of thermoplastic material.

8. The operating fluid tank as claimed in claim 1, wherein the deformation region is surrounded by the region formed of the second thermoplastic material.

9. The operating fluid tank as claimed in claim 1, wherein the second thermoplastic material has a greater stiffness than the first thermoplastic material.

10. The operating fluid tank as claimed in claim 1, wherein the at least two mutually complementary shells are injection-molded shells.

11. The operating fluid tank as claimed in claim 1, wherein at least one shell is a co-injection injection-molded shell or a sandwich injection-molded shell.

12. The operating fluid tank as claimed in claim 1, wherein the region formed of the second thermoplastic material encompasses the deformation region.

13. The operating fluid tank as claimed in claim 1, wherein the deformation region is formed as a deformation window which is surrounded by the region formed of the second thermoplastic material.

14. The operating fluid tank as claimed in claim 1, wherein the at least one shell of the shells which comprises at least the first layer having at least one region formed of the first thermoplastic material and another region formed of the second thermoplastic material is a single layer shell.

Description

(1) The invention will be explained hereinbelow on the basis of an exemplary embodiment shown in the drawings, in which:

(2) FIG. 1: shows a sectioned exploded view of an operating fluid tank according to the invention,

(3) FIG. 2: shows an illustration of an operating fluid tank according to the invention with a three-layered wall structure and externally attached fastening means,

(4) FIG. 3: shows a further variant of the operating fluid tank according to the invention with a flexible filler pipe,

(5) FIG. 4: shows a variant of the operating fluid tank according to the invention with internally integrally attached, flexible baffle elements, and

(6) FIG. 5: shows a view of a tank wall of the operating fluid tank according to the invention with a deformation window provided in the tank wall.

(7) The operating fluid tank 1 according to the invention is composed essentially of at least two injection-molded shells 2a, 2b, the shell 2a forming an upper shell and the shell 2b forming a lower shell of the operating fluid tank 1. The shells in each case form a peripherally circumferential flange 3a, 3b, at which the shells 2 are welded to one another to form the closed operating fluid tank. Each of the shells 2 has been obtained by co-injection molding, both the upper shell and the lower shell 2a, 2b in each case having integrally attached structures, for example in the form of partition wall elements 4a, 4b. The partition wall elements 4a, 4b can divide the operating fluid tank 1 into various compartments, which more or less communicate with one another. These partition wall elements 4a, 4b likewise perform the function of baffle wall elements.

(8) In the exemplary embodiment of the invention as shown in FIG. 1, the shells 2 each have a two-layered form, comprising an inner layer 5 and also an outer layer 6.

(9) At this point, it should be emphasized that the shells 2 of the operating fluid tank 1 according to the invention can in principle also have a single-layered form, without departing from the basic principle that at least one of the shells is composed of two different plastics either with different physical properties or with different structural/molecular properties.

(10) In principle, however, it also lies within the context of the invention to form one or both of the shells of the operating fluid tank 1 in each case with multiple layers, in which case at least one of the shells has a plurality of planar regions made of different thermoplastic materials.

(11) In this respect, it is possible to inject a second thermoplastic material into at least one aperture in at least one shell made of a first thermoplastic material. As an alternative or in addition, it is possible to thicken at least one wall region of at least one shell with a second thermoplastic material of differing elasticity or of differing molecular structure by injection molding.

(12) With reference to FIG. 1, it can be provided that the inner layer 5 and the outer layer 6 consist of thermoplastic materials of differing molecular structure, but these layers can also be formed from identical thermoplastic materials with different fillers or in each case filled and unfilled.

(13) Finally, the layers can be formed in such a way that, by way of example, the inner layer 5 is filled in certain regions and the outer layer 6 is not filled.

(14) The operating fluid tank 1 shown in FIG. 1 is formed, for example, as a tank for an aqueous urea solution for selective catalytic exhaust-gas denitrogenization on a diesel motor vehicle.

(15) The outer layer 6 of the upper shell 2a is formed from a polyolefin, whereas the inner layer 5 of the upper shell 2b is formed from a polyamide.

(16) The lower shell 2b, by contrast, comprises an inner layer 5 made of a polyamide and an outer layer 6 made of a thermoplastic elastomer, which forms a stone chip guard for the lower shell 2b.

(17) The operating fluid tank 1 as per the variant shown in FIG. 2 comprises two shells 2 each having a three-layered form, where an inner layer 5 consists of a thermoplastic material with a thermally conductive filler, an intermediate layer 7 consists of a foamed thermoplastic material and an outer layer 6 consists of a thermoplastic material which is elastic at least in certain regions. Fastening lugs 8 are integrally molded onto the outer layer 6 of the upper shell 2a, it being possible for these fastening lugs to have, for example, a higher elasticity or a higher strength than the rest of the material of the outer layer 6.

(18) In the variant of the operating fluid tank 1 shown in FIG. 3, this comprises an outer layer 6 with an integrally attached filler pipe 9 consisting of a thermoplastic elastomer.

(19) In the exemplary embodiment shown in FIG. 4, the upper shell 2a and the lower shell 2b likewise each have a multilayered form, these having an inner layer made of a thermoplastic elastomer and an outer layer 6 made of a thermoplastic material of higher strength, for example based on HDPE.

(20) Baffle wall elements 10a, 10b are integrally attached to the inner layer 5. These baffle wall elements 10a, 10b likewise consist of a thermoplastic elastomer, and therefore they can optimally yield in a defined manner in the event of severe surge movements of the fluid stored in the operating fluid tank 1, and thus consume some of the energy of the fluid surge.

(21) FIG. 5, finally, illustrates a further variant of the operating fluid tank 1 according to the invention. FIG. 5 shows only a section of a tank wall 11 of the operating fluid tank 1. This tank wall 11 can have a single-layered and also multilayered form.

(22) In the tank wall 11, provision is made of at least one deformation window made of an elastically deformable thermoplastic material with a relatively low strength which is surrounded by a relatively stiffer thermoplastic material of the tank wall 11. The thermoplastic material which fills the deformation window 12 can be, for example, a thermoplastic elastomer which has been injected into the tank wall 11 by co-injection.

LIST OF REFERENCE SIGNS

(23) 1 Operating fluid tank 2a Upper shell 2b Lower shell 3a, 3b Flange 4a, 4b Partition wall elements 5 Inner layer 6 Outer layer 7 Intermediate layer 8 Fastening lugs 9 Filler pipe 10a, 10b Baffle wall elements 11 Tank wall 12 Deformation window