Interior paneling part comprising a planar heating element and method for the production thereof

Abstract

In accordance with the present disclosure, there is provided a method for producing an interior trim part. The method includes introducing a planar heating element into a cavity of a mold tool. The planar heating element has a first planar side facing away from a visible side of the interior trim part and a second planar side opposite to the first planar side, the mold tool has a plurality of protrusions protruding into the cavity, and the first planar side is seated on at least a portion of the plurality of protrusions. The method further includes adding a foam material into the cavity to cover the planar heating element, such that a foam layer is formed on both the first and second planar sides.

Claims

1. An interior trim part for an interior of a vehicle, comprising: a foam body having a first outer side and a second outer side opposing to each other, at least a portion of the second outer side including a plurality of depressions; a planar heating element embedded within the foam body and having a first planar side facing towards the first outer side of the foam body, and having an opposing second planar side facing towards the second outer side of the foam body, wherein: the first outer side of the foam body is separated from the first planar side of the heating element; the second outer side of the foam body is separated from the second planar side of the heating element; and at least a portion of the planar heating element is exposed at a base of the depressions; and a decorative layer disposed on the first outer side of the foam body, the decorative layer having a visible side and an opposing backside, the visible side being visible from the vehicle interior and facing away from the foam body, and the opposing backside facing the first outer side of the foam body.

2. The interior trim part according to claim 1, wherein the depressions have a shape corresponding to at least one of a cone, a truncated cone, a cylinder with rounded edges, or a hemisphere.

3. The interior trim part according to claim 1, wherein at least a portion of the second outer side includes the depressions arranged at regular intervals along the second outer side.

4. The interior trim part according to claim 3, wherein the planar heating element has a plurality of through-passages evenly distributed over the planar heating element and filled with a material of the foam body.

5. The interior trim part according to claim 4, wherein: a distance between centers of neighboring depressions is between about 5 mm to about 20 mm; and a diameter of the depressions at the second outer side of the foam body is between about 4 mm to about 15 mm.

6. The interior trim part according to claim 1, wherein the planar heating element has a plurality of through-passages distributed over the planar heating element and filled with a material of the foam body.

7. The interior trim part according to claim 6, wherein the planar heating element includes a plurality of heating strands.

8. The interior trim part according to claim 6, wherein the plurality of through-passages are evenly distributed over the planar heating element.

9. The interior trim part according to claim 1, wherein the depressions have a depth of about 4 mm to about 15 mm.

10. The interior trim part according to claim 1, wherein the planar heating element is formed of at least one of a heating mat, a heating foil, or a metallized sheet material.

11. The interior trim part according to claim 1, wherein: a distance between centers of neighboring depressions is about 5 mm to about 20 mm; and a diameter of the depressions at the second outer side of the foam body is about 4 mm to about 15 mm.

12. The interior trim part according to claim 1, wherein a plane extending through the base of the depressions defines a position of the planar heating element.

13. The interior trim part according to claim 1, wherein the depressions are configured to increase deformation of the foam body under pressure.

14. The interior trim part according to claim 1, wherein the depressions have varying depths.

15. The interior trim part according to claim 14, wherein the depressions have a shape corresponding to at least one of a cone, a truncated cone, a cylinder with rounded edges, or a hemisphere.

16. The interior trim part according to claim 14, wherein: a distance between centers of neighboring depressions is about 5 mm to about 20 mm.

17. The interior trim part according to claim 14, wherein the planar heating element includes a plurality of heating strands.

18. The interior trim part according to claim 1, wherein at least a portion of the second outer side includes the depressions arranged in a grid pattern along the second outer side.

19. The interior trim part according to claim 18, wherein the grid pattern is at least one of hexagonal, triangular, or quadratic.

20. The interior trim part according to claim 18, wherein the depressions have a shape corresponding to at least one of a cone, a truncated cone, a cylinder with rounded edges, or a hemisphere.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described hereafter by way of examples based on the accompanying drawings.

(2) FIGS. 1A to 1D are sectional views of a mold tool used in an exemplary method according to the disclosure for producing an interior trim part according to the disclosure.

(3) FIG. 2A shows a perspective view of raised protrusions of the mold.

(4) FIG. 2B shows a cross-sectional view of an exemplary protrusion of the mold.

(5) FIG. 3 shows a plan view of an inner side of a mold.

(6) FIG. 4 is an illustration of a heating mat to be introduced into the interior trim part.

(7) FIG. 5 shows a cross-section of an interior trim part including an inserted heating element.

DETAILED DESCRIPTION

(8) Unless indicated otherwise, identical or functionally equivalent components are denoted by the same reference numerals in the figures. Further modifications mentioned in this context can be combined with each other to form new embodiments.

(9) FIGS. 1A to 1D show sectional views of a mold tool 50, which is used to implement the methods according to the present disclosure for producing an interior trim part 1. More specifically, FIGS. 1A to 1D each show a stage of the production method.

(10) As is shown in FIG. 1A, a suitable mold tool 50 has two mold halves 51 and 52. Each of these can have a cutout, which together define a mold cavity 54. The mold tool 50 further has feeds 55 via which a foam material 31 can be introduced into the mold cavity 54. The division of the mold tool 50 into two mold halves 51 and 52 shall only be understood as an example here. The shown embodiment of the mold cavity 54 is also only provided to better illustrate the basic idea of the disclosure.

(11) As shown in FIG. 1A, the mold tool 50 has protrusions 53 on at least one side of the mold cavity 54, which protrude into the mold cavity 54. The protrusions 53 are provided at least in some sections on the mold tool 50. In the figures, the protrusions 53 are provided over an entire side of the mold tool 50. However, the protrusions 53 can also be provided on multiple sides of a more complex mold design. In some embodiments, as shown in FIGS. 1A-1D, the sides in the mold cavity 54 opposite the protrusions 53 have a smooth surface, i.e., they are designed without protrusions.

(12) The protrusions 53 of the mold tool 50 are intended for a planar heating element 40 to be placed thereon. This is illustrated in FIG. 1B. In some embodiments, the protrusions 53 are dimensioned and designed for this purpose in such a way that the planar heating element 40 can be supported by the protrusions 53 without deformations of the planar heating element 40. By placing the planar heating element 40 on the raised protrusions 53 of the mold tool 50, the planar heating element 40 can be positioned with respect to a direction perpendicular to the planar sides of the heating element 40 (here, the z-direction).

(13) To position the planar heating element 40 in the x- and y-directions on the raised protrusions 53, locating pins can be attached to the structure of the raised protrusions 53. The pins engage in corresponding locating holes of the planar heating element 40. Both elements, the locating pins and locating holes, are not shown in the drawings. The locating holes can be stamped into the planar heating element 40. In some embodiments, the locating pins are disposed in the peripheral region of the mold tool 50. In some embodiments, the locating pins are provided in a region of an overhang of the finished foam body, which is cut off during the further processing of the interior trim part, so that no cutouts, caused by the locating pins, are visible on the finished foam body.

(14) Moreover, the sealing region of the mold tool 50 can be placed on the peripheral regions of the planar heating element 40, so that positioning in the x- and y-directions is also possible without locating pins and corresponding locating holes. A cable (not shown) for supplying the heating element 40 with power is provided on the planar heating element 40. One end of the cable is arranged at the positioned heating element 40 within the mold cavity 54, with another end being arranged outside the mold tool 50.

(15) FIGS. 1C and 1D show the mold tool 50 in the closed state. In said state, foam material 31 can be added to the mold cavity 54 via the feeds 55. The hollow or intermediate spaces between the raised protrusions 53 ensure that the planar heating element 40 can be covered in foam in such a way that a foam layer is formed on both sides of the planar heating element 40.

(16) In FIGS. 1A-1D, the feed openings 55 for the foam material 31 in the mold tool 50 are located opposite the raised protrusions 53. However, this shall only be understood as an example, and the arrangement of the feeds 55 can be varied appropriately for more complicated interior trim parts 1 and mold tools 50. With the arrangement shown in FIGS. 1A-1D, the foam material 31 flowing in through the feeds 55 pushes the planar heating element 40 against the raised protrusions 53, and it is therefore ensured that the planar heating element 40 does not lift off the raised protrusions 53 during the foaming process. This ensures a reliable positioning of the planar heating element 40 in the finished interior trim part 1 or foam body 10.

(17) In some embodiments, a polyurethane foam is used as the foam material 31, which is pressure-resistant and nonetheless has a soft feel. The planar heating element 40 may be a heating mat, in which a heating strand 41 is knitted into a non-woven fabric, as shown in FIG. 4. As an alternative, it is also possible to use heating foils or other metallized sheet materials. In some embodiments, the planar heating element 40 is flexible, whereby the embedding of the heating element into the foam layer is simplified.

(18) After an appropriate reaction time (approximately 120 seconds for a polyurethane (PU) foam), the foam body 10, together with the embedded planar heating element 40, can be removed. Thereafter, the foam body 10, including the planar heating element 40, can be suitably cut to size as needed. Finally, the foam body can be laminated.

(19) By seating the planar heating element 40 on the raised protrusions 53 of the mold tool 50, it is ensured that the planar heating element 40 has appropriate distance on both planar sides or outer sides of the foam body 10.

(20) An exemplary embodiment of the protrusions 53 of the mold tool 50 is shown in FIG. 2A. Here, the protrusions 53 are arranged in a regular protuberance structure. In the example shown in FIG. 2A, the protrusions 53 have approximately the shape of hemispheres, which protrude into the mold cavity 54. Alternatively, it has been found that cylinders, cones, or truncated cones, in each case with rounded edges, also represent a suitable structure for the raised protrusions 53.

(21) Such a truncated cone having rounded edges is shown in FIG. 2B. It has a diameter d of approximately 6 mm, and the angle of inclination of the sides in this example is approximately 20 degrees. However, both parameters can be varied as needed. The height h can also be varied as needed. In general, it has been found that protrusions 53 having a blunt contact surface are suitable because the planar heating element 40 can be supported thereon well. In addition, the round base area of cylinders, cones, or truncated cones or hemispheres ensures that the foam material 31 can flow largely unimpaired between the protrusions 53.

(22) The through-flow of the foam material in the structure of the protrusions 53 can moreover be influenced by appropriate arrangement of the protrusions 53. For example, by varying the distances of the protrusions 53 from each other, such as by using protrusions 53 having differing shapes, the flow of the foam material 31 can be influenced. The arrangement of the protrusions can additionally result from the component geometry of the finished interior trim part 1 or of the foam body 10. In regions of larger, planar surfaces, for example, an even distance between the protrusions 53 can be realized. In curvature regions, however, larger distances can be selected, or smaller diameters d at the same height h.

(23) Such a need-specific embodiment of the protrusions 53 is shown in FIG. 3 by way of example, for a complicated mold tool part 52. Here, the protrusions 53 are divided into different, regular structures in some sections. Regular structures here means that, within a structure, in particular the distance between centers of the protrusions 53 is set to a uniform value. The distance between centers of neighboring protrusions 53 is 12 mm in the present example. In some embodiments, the diameters of the protrusions 53 are smaller than the distance between the protrusions 53. At these distances between centers, it can be ensured, for example, that a heating mat shown in FIG. 4 is not pushed into the spaces between the protrusions 53 as soon as the foam material 31 is introduced.

(24) The height h of the protrusions 53 is about 10 mm and may be uniform among all the protrusions 53. In some embodiments, the height of the individual protrusions may vary, if, for example, the geometry of the finished foam body 10, or of the interior trim part 1, requires. For example, by appropriately selecting the height h of the protrusions 53, the distance between the planar sides of the foam body 10 and the planar heating element 40 can remain consistent. The total height of the foam body is about 25 mm. The foam layer, opposite the planar side of the planar heating element that is/was seated on the protrusions 53, has a height of about 10 mm.

(25) In some embodiments, as shown in FIG. 3, the protrusions 53 are arranged, for example, in a regular hexagonal grid, or a regular arrangement in rows and columns. In some embodiments, the protrusions 53 may be arranged in a different manner, such as in a triangular grid or a quadratic grid, as needed when molding the foam body 10 and during the subsequent installation of the interior trim part 1.

(26) FIG. 4 shows a planar heating element 10 by way of example as a heating mat. In addition to heating strands 41, which are knitted into a non-woven carrier fabric, the heating mat has through-passages 42. These are evenly distributed over the entire heating mat and formed by stamping, for example. The task of the through-passages 42 is to ensure the through-flow of foam material 31 when the foam material 31 is added into the mold cavity 54. This ensures an even and fast distribution of the foam material 31.

(27) In some embodiments, a minimum diameter of the through-passages 42 is about 4 mm. In some embodiments, to ensure a consistent flow of foam material 31 throughout the heating mat, the diameter of through-passages 42 may be about 6 mm.

(28) FIG. 5 shows a sectional view of a finished interior trim part 1, which was formed using the mold tool 50 according to the present disclosure having the raised protrusions 53, which protrude into the mold cavity 54. The interior trim part 1 includes the planar heating element 40 and the foam body 10, into which the planar heating element 40 is embedded. As shown in FIG. 5, the outer sides of the foam body 10a and 10b in each case are located at a distance from the respective planar side 40a and 40b of the planar heating element 40. The foam body 10 has open depressions 32 on one of the outer sides.

(29) Said open depressions 32 can be considered a mirror image of the raised protrusions 53 of the mold tool 50. In the present example, the depressions 32 have a height of about 10 mm and they have a truncated cone shape with rounded edges. The diameter of these open depressions 32 on the outer side is about 6 mm at a distance between centers of about 12 mm.

(30) In some embodiments, as a result of the method for producing the interior trim part 1, according to which the planar heating element 40 is seated on the projections 53 when the foam material 31 is being introduced, the planar heating element 40 is exposed at the base of the depressions 32 in the finished foam body 10. That is, one planar side 40b of the planar heating element 40 at the base of the open depressions 32 is exposed.

(31) As a result of the through-passages 42 in the planar heating element 40, the foam body 10, or the interior trim part 1, can further be characterized by corresponding openings (not shown), which are distributed in the finished foam body 10 over the entire planar heating element 40 and filled with the material of the foam body 10.

(32) The interior trim part 1 is further provided with a decorative layer 60 that closes the interior trim part 1 toward the visible side 1a thereof. The decorative layer 60 adjoins the outer side 10a of the foam body 10, which is located opposite the outer side 10b of the foam body 10 on which the open depressions 32 are provided. In other words, the decorative layer 60 is seated on the planar side 10a of the foam body 10, which has no open depressions 32 and is smooth.

(33) Possible materials for the decorative layer 60 include, for example, leather, including natural or synthetic leather, fabric films, or other planar materials. In some embodiments, the decorative layer 60 can be laminated onto the foam body 10 after the same has been formed. As an alternative, the decorative layer 60 can also be already inserted into the mold cavity 54 on a wall during the foaming process of the foam body 10.

(34) The method according to the disclosure, the basic idea of which provides for a planar heating element to be introduced into a cavity of a mold tool in such a way that one of the planar sides of the planar heating element is seated at least in sections on multiple raised protrusions 53 of the mold tool 50, can be used to produce foam bodies 10, or interior trim parts 1 including an inserted planar heating element 40, which is positioned in the thickness direction or z-direction.

(35) This ensures that the contour of the planar heating element is not apparent toward the visible side, and that a trim part having a smooth surface or a uniform smooth surface, is created. Moreover, the feel of the interior trim part, in particular the soft-hard sensation upon contact with the trim part, is not adversely affected by the planar heating element. This would be the case, for example, if the planar heating element were exposed on the visible side 10a of the foam body 10 due to mispositioning in the thickness direction. In addition, it can be ensured that the contour of the planar heating element 40 is also not apparent on the side 10b of the foam body 10 which is located opposite the visible side 10a. This not only reduces heat losses, but also lowers the likelihood of damaging the planar heating element 40 or the carrier element.

(36) A further advantage is that a soft feel of the material can be realized by generating a defined foam layer on both sides, without the heating action of the planar heating element being impaired as a result of an excessively thick foam layer. It has furthermore been shown that the soft feel can even be increased further by the structure of the open depressions 32 in the foam body 10, or by the raised protrusions 53 of the mold tool, because the large clearances that are created by such a structure in the foam body 10 favor a soft feel.