METHOD OF PRODUCING AN OPERATING FLUID TANK

Abstract

A method of producing an operating fluid tank includes providing a mold core produced from a mold core material. The mold core has a holding region, by which the mold core is held in a tool mold or in a plastic molding machine. The mold core is surrounded with a plastic melt, and an opening remains in the operating fluid tank. The mold core material is removed from the operating fluid tank by the remaining opening, and a structural element is arranged at the mold core separate from the holding region, and is held by the mold core while being surrounded with the plastic melt. An inner surface of the operating fluid tank is then formed, to which a structural feature arranged on the structural element is transferred. The structural element is removed from the operating fluid tank through the remaining opening after at least partial hardening of the melt.

Claims

1. A method of producing an operating fluid tank of plastic for a motor vehicle including the following steps: providing a mold core produced from a, preferably pourable or flowable, mold core material, wherein the mold core has at least one holding region, by way of which the mold core is held in a tool mold or in a plastic molding machine, surrounding the mold core with a plastic melt, wherein at least one opening remains in the operating fluid tank in the at least one holding region, by way of which the mold core is held in a tool mold or a plastic molding machine, and removing the mold core material from the operating fluid tank by way of the remaining opening, wherein a preferably metallic and/or ceramic structural element is arranged at a limited portion of the mold core, that is separate from the at least one holding region, and is held by the mold core while being surrounded with the plastic melt, wherein while being surrounded with the plastic melt an inner surface of the operating fluid tank is formed, to which a structural feature arranged on the structural element is transferred while being surrounded with the plastic melt and wherein the structural element is removed from the operating fluid tank through the remaining opening after at least partial hardening of the plastic melt.

2. A method of producing an operating fluid tank of plastic for a motor vehicle including the following steps: providing a mold core produced from a, preferably pourable or flowable, mold core material, wherein the mold core has at least one holding region, by way of which the mold core is held in a tool mold or in a plastic molding machine, surrounding the mold core with a plastic melt, wherein at least one opening remains in the operating fluid tank in the at least one holding region, by way of which the mold core is held in a tool mold or a plastic molding machine, and removing the mold core material from the operating fluid tank by way of the remaining opening, wherein a stable-shape functional element is arranged at a limited portion of the mold core, that is separate from the at least one holding region, and is held by the mold core while being surrounded with the plastic melt, wherein while being surrounded with the plastic melt an inner surface of the operating fluid tank is formed, to which the functional element is connected while being surrounded with the plastic melt and wherein the functional element is held in material-bonded and/or positively locking relationship after hardening of the plastic melt and removal of the mold core material by the operating fluid tank in such a way that the functional element has access to the interior of the operating fluid tank.

3. The method as set forth in claim 1, wherein the structural feature is formed by a smooth surface of the structural element.

4. The method as set forth in claim 1, wherein the structural element has a flat surface region on which the structural element is arranged.

5. The method as set forth in claim 2, wherein the functional element includes an electronic functional element, preferably a sensor and/or a transmitting-receiving unit.

6. The method as set forth in claim 2, wherein the functional element includes a sealing element and/or a fixing element.

7. The method as set forth in claim 1, wherein the functional element and/or the structural element is held in positively locking and/or force-locking and/or material-bonded relationship by the mold core while being surrounded with plastic melt.

8. The method as set forth in claim 1, wherein the mold core has two holding regions, by way of which the mold core is held in a tool mold or a plastic molding machine.

9. The method as set forth in claim 1, wherein arranged at the at least one holding region is a preferably metallic holding means with which the mold core is held in a tool mold or a plastic molding machine.

10. The method as set forth in claim 1, wherein the mold core is composed of at least two segments, wherein each two segments are connected together by way of connecting means and wherein the one or more connecting means after the core is surrounded with the plastic melt is or are removed from the operating fluid tank through the remaining opening.

11. The method as set forth in claim 1, the mold core comprises sand or foam balls.

12. The method as set forth in claim 11, wherein the mold core has a casing comprising a soluble or crushable material.

13. The method as set forth in claim 1, wherein the mold core is produced by means of a 3D printing process.

14. A mold core for the production of an operating fluid tank of plastic for a motor vehicle according to the method as set forth in claim 1.

15. An operating fluid tank for a motor vehicle, in particular produced according to the method as set forth in claim 1, wherein the operating fluid tank is injection molded from a plastic.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Further advantages and details of the invention will be discussed for various embodiments by way of example with reference to the following Figures in which:

[0043] FIG. 1 is a diagrammatic cross-sectional view of an operating fluid tank with mold core arranged therein,

[0044] FIG. 2 is a partly sectional diagrammatic perspective view of a mold core composed of segments,

[0045] FIGS. 3a through 3c are diagrammatic views relating to the arrangement of a functional element in the interior of an operating fluid tank and relating to the transfer of structural elements on to the inner surface of an operating fluid tank,

[0046] FIG. 4 is a diagrammatic view of an internal region of an operating fluid tank with transferred structural feature,

[0047] FIG. 5 is a diagrammatic view relating to the arrangement of a mold core in a tool mold, and

[0048] FIGS. 6a through 6e are diagrammatic views relating to the method procedure according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0049] FIG. 1 is a diagrammatic cross-sectional view showing a mold core 2 according to the invention which is composed of three segments 2a, 2b, 2c, the segments 2a, 2b, 2c being respectively connected by way of a connecting means 17. At limited portions of the mold core 2 a structural element 6 and a stable-shape functional element in the form of a sensor 12 are held by the mold core 2. Further stable-form functional elements which are held at limited portions of the mold core 2 are a fixing element 13 in the form of a thread, a cable duct 15 and a general functional element 7, for example an RFID chip. The structural element 6 and the functional elements 7, 12, 13, 15 are held by the mold core 2 while being surrounded with the plastic melt 8. FIG. 1 shows the operating fluid tank after at least partial hardening of the plastic melt 8 and after removal from the tool mold 4. Subsequently the mold core 2a, 2b and 2c, the connecting means 17 and the structural element 10 are removed from the interior of the operating fluid tank 1.

[0050] In the situation shown in FIG. 1 the mold core 2 according to the invention is already surrounded with a partially hardened plastic melt 8 in the form of a thermoplastic material. After hardening of the melt 8 the functional elements 7, 12, 13 and 15 are held by the operating fluid tank in material-bonded and/or positively locking relationship. The structural element 6 has a flat surface region with a structural feature 10 arranged thereon, for example a smooth surface which is transferred to the inner surface 9 of the operating fluid tank when the core is surrounded with the plastic melt 8.

[0051] The above-mentioned limited regions are separate from the holding region 3 at which the mold core 2 is held in a tool mold 4. After hardening of the plastic melt 8 the mold core material is removed by way of the opening 5 which remains in the operating fluid tank 1 at the holding region 3. The connecting means 17 and the structural element 6 are also removed by way of the remaining opening 5.

[0052] Particularly in regard to the functional element 7 and the sensor 12 it can be seen that those elements are arranged in an undercut region of the operating fluid tank 1 and are therefore surrounded with plastic melt 8 apart from accesses to the interior and the exterior of the operating fluid tank. In that case in regard to the sensor 12 a region on the outside of the operating fluid tank 1 is accessible, for example to connect a data or control line. The undercut configurations are possible in particular by virtue of the segmentation of the mold core 2.

[0053] FIG. 2 is a perspective diagrammatic view of the mold core 2 according to the invention, wherein the segments 2b and 2c shown in FIG. 1 are illustrated in section so that the connecting means 17 with which the segments 2a, 2b and 2c are connected together can be seen. The segment 2c is shown in its complete form. Such segments 2a, 2b and 2c permit strongly undercut configurations for the operating fluid tank.

[0054] FIG. 3a in the left view shows how a function a element 7, for example a piezoelectric element, is held by the mold core 2. The functional element 7 has holding regions which project perpendicularly from its longitudinal extent and around which the mold core material is arranged so that this affords a positively locking connection between the functional element 7 and the mold core 2. The mold core 2 is surrounded with plastic melt 8, for example a thermoplastic material, for example in a tool mold 4. When then the plastic melt 8 hardens the stable-shape functional element 7 after removal of the mold core material is held by the operating fluid tank according to the invention in positively locking and material-bonded relationship and has access to the interior in order for example to detect data in respect of the content of the operating fluid tank 1. At the same time in this case the functional element 7 is held by the operating fluid tank 1 in such a way that access still remains to the exterior of the operating fluid tank 1, for example to connect a data or control line.

[0055] FIG. 3b diagrammatically shows how a structural feature 10 in the form of a smooth surface on a flat region of a structural element 6, which is held by the mold core 2 while being surrounded with plastic melt 8 is transferred on to the inner surface 9 of an operating fluid tank 1 according to the invention and comprising a thermoplastic material. In that case a negative configuration of the surface of the structural element 6 is transferred. After removal of the mold core material there remains a region 18 in which the inner surface 9 of the operating fluid tank 1 is smooth while the inner surface 9 apart therefrom constitutes a region 14 with a rough surface.

[0056] FIG. 3c diagrammatically shows how a structural element 6 having a flat region on which structural features 10 in the form of different rib shapes are arranged is transferred on to the inner surface 9 of an operating fluid tank 1 according to the invention. The structural element 6 is held by the mold core 2 while being surrounded with plastic melt 8. That results in a negative shape in respect of the rib configurations on the inner surface 9 of the operating fluid tank in the region in which the structural element 6 was held by the mold core 2 while being surrounded with the plastic melt 8. The rib shapes make it possible for the inner surface 9 of the operating fluid tank 1 to have for example different undercut configurations in that region, thereby achieving particularly high stability.

[0057] FIG. 4 is a diagrammatic perspective view showing the inner region of an operting fluid tank 1 according to the invention, wherein a region 18 has a smooth surface which was transferred by the transfer of a structural feature 10 of a structural element 6. That surface region represents a smooth negative configuration for the surface region of the structural element 6. In comparison the region 15 has a rough surface which is produced when surrounding the mold core 2 with plastic melt 8. FIG. 3b diagrammatically shows by way of example how such a structural feature 10 in the form of a smooth surface is transferred on to the inside wall of the operating fluid tank 1.

[0058] FIG. 5 is a diagrammatic view showing how a mold core 2 according to the invention is held in a tool mold 4 of a plastic injection molding machine.

[0059] A structural element 6 is adhesively attached to the mold core 2 and is thereby held by the mold core 2 while being surrounded with plastic melt 8. A structural element 10 in the form of a smooth surface is thereby transferred on to the inner surface 9 of the resulting operating fluid tank 1 according to the invention. The mold core 2 has two holding regions 3, by way of which the mold core 2 is held in the tool mold 4. For that purpose holding means 16, for example in the form of metal pins, are arranged on or in the mold core 2. The holding means 16 are held by way of clips 19 in the tool mold 4. After the mold core 2 is surrounded with plastic melt and after hardening, removal of the mold core material and removal of the holding means 16 openings 5 remain in the operating fluid tank 1.

[0060] FIGS. 6a through 6c diagrammatically show various steps in the method according to the invention, the mold core 2 being held in a tool mold 4 by way of the holding means 16 in FIG. 6a. The mold 4 is then closed and liquid plastic melt is injected into the mold 4, for example by way of a plasticizing screw 20 of a plastic injection molding machine. That can be for example a thermoplastic material.

[0061] FIG. 6b shows how liquiid plastic melt 8 is injected into the mold 4 by the plasticizing screw 20 and the mold core 2 is surrounded with plastic melt 8 by being arranged in the cavity 21. No plastic melt 8 is arranged in the holding regions 3, in which the holding means 16 are arranged. Here therefore openings 5 remain in the operating fluid tank 1.

[0062] FIG. 6c diagrammatically shows the step of removal from the mold, in which the blank with the operating fluid tank 1, the holding means and the mold core 2 arranged within the operating fluid tank 1 is removed from the mold 4.

[0063] FIG. 6d diagrammatically shows how the mold core 2 is flushed out of the interior of the operating fluid tank 1 for example with water or a solution. In that situation the mold core material can flow out by way of the opening 5.

[0064] The finished component is diagrammatically shown in FIG. 6e. For the sake of better clarity functional elements 7 or transferred structural features 10 are not shown here.

LIST OF REFERENCES

[0065] 1 operating fluid tank [0066] 2 mold core with segments 2a, 2b, 2c [0067] 3 holding region [0068] 4 tool mold [0069] 5 operating fluid tank opening [0070] 6 structural element [0071] 7 functional element [0072] 8 plastic melt [0073] 9 inside surface of the operating fluid tank [0074] 10 structural feature [0075] 11 operating fluid tank interior [0076] 12 sensor [0077] 13 fixing element [0078] 14 region with rough surface [0079] 15 cable duct [0080] 16 holding means [0081] 17 connecting means [0082] 18 region with smooth surface [0083] 19 clip [0084] 20 plasticzing screw [0085] 21 cavity