METHOD FOR WELDING A HEAT SHIELD DURING MANUFACTURING OF A VEHICLE COMPONENT

Abstract

A method for welding a heat shield during manufacturing of a vehicle component made from a thermoplastic material. The heat shield includes: a reinforcement layer made from a thermoplastic material which is weldable to the thermoplastic material of the vehicle component; and a heat shielding material that differs from the thermoplastic material of the reinforcement layer and is configured to decrease transfer of heat through the reinforcement layer to the vehicle component. The method includes: heating the heat shield to bring the thermoplastic material of the reinforcement layer in a molten state; placing the heated heat shield in a mold; bringing into the mold the thermoplastic material of the vehicle component in a molten state; welding the thermoplastic material of the reinforcement layer being in a molten state to the thermoplastic material of the vehicle component being in a molten state, by blow molding the vehicle component in the mold.

Claims

1-10. (canceled)

11. A method for welding a heat shield during manufacturing of a vehicle tank, or a filler pipe, the tank or the pipe being made from a thermoplastic material, the heat shield including: a reinforcement layer made from a thermoplastic material which is weldable to the thermoplastic material of the vehicle tank or filler pipe; and a heat shielding material which differs from the thermoplastic material of the reinforcement layer and which is configured to decrease transfer of heat through the reinforcement layer to the vehicle tank or filler pipe; the method comprising: heating the heat shield to bring the thermoplastic material of the reinforcement layer in a molten state; placing the heated heat shield in a mold; bringing into the mold the thermoplastic material of the vehicle tank or filler pipe in a molten state; welding the thermoplastic material of the reinforcement layer being in a molten state to the thermoplastic material of the vehicle tank or filler pipe being in a molten state, by blow molding the vehicle tank or filler pipe in the mold.

12. A method of claim 11, wherein the bringing into the mold the thermoplastic material of the vehicle tank or filler pipe brings a tubular wall portion into the mold by a shaping tool of an extrusion die.

13. A method of claim 11, wherein the bringing into the mold the thermoplastic material of the vehicle tank or filler pipe brings an extruded sheet into the mold.

14. A method of claim 11, wherein the heat shield is preformed before placing the heat shield in the mold.

15. A method of claim 11, wherein the heat shielding material comprises a heat-insulating layer of a heat insulation material, the heat-insulating layer being provided against the layer of thermoplastic material of the vehicle tank or filler pipe.

16. A method of claim 11, wherein the heat shielding material comprises a reflective layer that forms an outer layer of the heat shield, the reflective layer configured to reflect heat radiation.

17. A method according to claim 16, wherein the reflective layer is adhered to the heat-insulating layer.

18. A method according to claim 16, wherein the reflective layer is adhered to the reinforcement layer.

19. A method for manufacturing a vehicle tank or filler pipe including a wall made of thermoplastic material, the method for manufacturing comprising: adhering a heat shield to the wall, the adhering comprises a method for welding a heat shield according to claim 11.

20. A heat shield for blocking and/or reducing transfer of heat to a vehicle tank or filler pipe of thermoplastic material, the heat shield comprising: a reinforcement layer made of a thermoplastic material that is configured to be welded to the thermoplastic material of the vehicle tank or filler pipe; and heat shielding material which differs from the thermoplastic material of the reinforcement layer and which is configured to decrease transfer of heat through the reinforcement layer to the vehicle tank or filler pipe.

21. A heat shield according to claim 20, the heat shielding material comprising a heat-insulating layer of a heat insulation material, the heat-insulating layer being arranged against the reinforcement layer.

22. A heat shield according to claim 21, the heat insulating material being a foam material.

23. A heat shield according to claim 20, the heat insulating layer having a thermal conductivity which is lower than 0.06 W/mK, and/or having a tensile modulus higher than 900 MPa and/or a thickness between 1 and 10 mm.

24. A heat shield according to claim 20, the heat shielding material comprising a reflective layer that forms an outer layer of the heat shield, the reflective layer being configured to reflect heat radiation.

25. A heat shield according to claim 24, the reflective layer being made of metal.

26. A heat shield according to claim 24, the reflective layer being adhered to the heat-insulating layer or to the reinforcement layer.

27. A heat shield according to claim 20, the heat shielding material comprising metal particles arranged at least in an outer layer of the heat shield, so that heat is reflected at the outer layer.

28. An assembly comprising: a vehicle tank or filler pipe including: an outer wall of a first thermoplastic material, and a heat shield according to claim 20, the heat shield being welded to the outer wall of the vehicle tank or filler pipe.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0039] The accompanying drawings are used to illustrate presently preferred non-limiting exemplary embodiments of devices of the present invention. The above and other advantages of the features and objects of the invention will become more apparent and the invention will be better understood from the following detailed description when read in conjunction with the accompanying drawings, in which:

[0040] FIG. 1 illustrates schematically a cross section of a vehicle tank with a heat shield according to an embodiment of the invention;

[0041] FIG. 2 illustrates a detailed cross section of part II of FIG. 1;

[0042] FIG. 3 illustrates a variant of the cross section of FIG. 2;

[0043] FIGS. 4A-4C illustrate the cross section of three variants of a heat shield for use in embodiments of the invention; and

[0044] FIGS. 5-7 illustrate schematically an embodiment of the method of the invention.

[0045] FIGS. 1 and 2 illustrate a first embodiment of a vehicle tank 10, here a saddle tank, made from a thermoplastic material, e.g. HDPE, wherein a heat shield 20 is adhered to an outer wall of the tank 10, and in particular to a wall part of the recess in the bottom of the tank 10. As illustrated in FIG. 2, the heat shield 20 comprises a reinforcement layer 21, a heat-insulating layer 22 and a reflective layer 23. The reinforcement layer 21 is made from a thermoplastic material, e.g. HDPE, which is weldable to the thermoplastic material of the vehicle tank. The reinforcement layer 21 is welded to the outer wall 10. In this embodiment the heat shielding material consists of the heat-insulting layer 22 and the reflective layer 23. These layers 22, 23 are configured for decreasing the transfer of heat through the reinforcement layer 21 to the vehicle tank.

[0046] Preferably, the reinforcement layer 21 is a fiber filled reinforcement layer, and more in particular a pre-impregnated fibers composite layer, i.e. a so-called prepreg layer. In other words, the reinforcement layer 21 may comprise a thermoplastic material and fibers. The fibers may be cut fibers, or woven or non-woven long or continuous fibers. Preferably, the fibers are included in the form of a woven mat of fibers, more preferably a woven mat of glass fibers. Preferably the reinforcement layer 21 has a thickness t2 between 0.1 and 2.5 mm, more preferably between 0.5 and 1.5 mm. Typically, the wall of the tank 10 has a thickness t1 between 2 and 10 mm, preferably between 3 and 8 mm.

[0047] The heat-insulating layer 22 is arranged against the reinforcement layer 21. Such a heat-insulating layer 22 will reduce the heat that is transferred to the tank 10. Preferably, the heat-insulating layer 22 is made of a foam material, e.g. polyurethane foam. Such a foam material may be glued against the reinforcement layer 21. Preferably, the foam material has a thermal conductivity (K-value), which is lower than 0.06 W/mK, more preferably lower than 0.04 W/mK. In a preferred embodiment the heat-insulating layer 22 has a thickness t3 between 1 and 10 mm, more preferably between 3 and 7 mm.

[0048] The reflective layer 23 forms the outer layer of the heat shield 20, and is configured for reflecting heat radiation. By reflecting heat radiation, less heat is transferred to the vehicle tank. Preferably, the reflective layer 23 is a metal layer. In an exemplary embodiment the reflective layer 23 is a thin aluminium sheet with a thickness t4 which is lower than 0.5 mm. The reflective layer 23 may be adhered, e.g. glued, to the heat-insulating layer. When no heat-insulating layer 22 is provided, the reflective layer 23 may be adhered to the reinforcement layer 21, see the variant of FIG. 3.

[0049] FIGS. 4A-4C illustrate three exemplary embodiments of a heat shield for use in a vehicle component of the invention. In the embodiment of FIG. 4A the reinforcement layer 21 is formed, e.g. compression molded, by including a fiber mat between two HDPE layers. A foam layer 22 is arranged, e.g. glued, against the reinforcement layer 21. A reflective outer layer 23 in the form of a thin aluminium sheet is fixed, e.g. glued against the foam material. Such a heat shield may be welded with its HDPE outer layer to the outer wall of a vehicle component such as a tank or a filler pipe. In the embodiment of FIG. 4B, a HDPE layer that does not contain fibers forms the reinforcement layer 21. A foam layer 22 is arranged, e.g. glued, against the reinforcement layer 21. No reflective outer layer is provided. In the embodiment of FIG. 4C, the reinforcement layer 21 is formed by arranging a fiber mat against/in a HDPE layer. A reflective outer layer 23 in the form of a thin aluminium sheet is fixed, e.g. glued against the fibre material.

[0050] FIGS. 5-7 illustrate an embodiment of the method of the invention for blow-molding a vehicle tank, from a thermoplastic material. In this embodiment the heat shield is overmolded on the tank as follows. The method comprises adhering a heat shield 20, 20′ to a wall of the vehicle tank. In a first step one or more heat shields 20, 20′ are placed in a mold 30, 30′. Afterwards the tank is blow-molded from a tubular wall portion 10, which is brought into the mold by means of a shaping tool 60 of an extrusion die 50. The temperature of the heat shields 20, 20′ and the mold 30, 30′ are such that the reinforcement layer is welded to the thermoplastic material 10 of the tank. Optionally, there may be provided additional heating means 40, 40′ in the mold 30, 30′ for heating the heat-shields 20, 20′.

[0051] In an alternative embodiment, the Twin Sheet Blow Molding Process (TSBM), as described in earlier patent applications WO2007/000454A1, WO2011/110480A1 in the name of the applicant, can be advantageously used. In this case, the shield is adhered onto the extruded sheet instead of to the tubular wall portion.

[0052] The heat shields 20, 20′ comprise a reinforcement layer made from a thermoplastic material that is welded to the thermoplastic material of the tank, and a heat shielding material which differs from said thermoplastic material of said layer and which is configured for decreasing the transfer of heat through the reinforcement layer to the tank. In a possible embodiment, after the blow-molding, the mold 30, 30′ is kept at a predetermined temperature during a predetermined time period for obtaining a good adherence of the reinforcement layer to the wall 10 of the blow-molded tank. In a possible embodiment, before placing the heat shield 20, 20′ in the mold 30, 30′, the heat shield 20, 20′ is heated to bring the thermoplastic material of the reinforcement layer thereof in a molten state. Also, the heat shield 20, 20′ may be preformed before positioning the heat shield 20, 20′ in the mold 30, 30′.

[0053] According to an alternative non-illustrated embodiment the adhering of the heat shield to a vehicle tank or filler pipe comprises welding the heat shield against an outer wall of an already molded vehicle tank or filler pipe.

[0054] In a preferred embodiment the heat shields 20, 20′ comprise a heat-insulating layer of a heat insulation material, said heat-insulating layer being arranged against the reinforcement layer. Preferably, the heat insulation material is a foam material. In addition or alternatively, the heat shields 20, 20′ may comprise a reflective layer, e.g. a metal layer, which forms an outer layer of the heat shield, said reflective layer being configured for reflecting heat radiation. Such a reflective layer may be glued against the reinforcement layer or against the insulation layer, if the latter is present. Alternatively the reflective layer may be laminated together with the reinforcement layer. In a preferred embodiment the reflective layer is a thin aluminium sheet.

[0055] The above-illustrated embodiments relate to tanks, but a skilled person will understand that the technical features and insights of the invention may be equally applied in filler pipes.

[0056] Whilst the principles of the invention have been set out above in connection with specific embodiments, it is to be understood that this description is merely made by way of example and not as a limitation of the scope of protection, which is determined by the appended claims.