JP7643264B2 - Vehicle interior parts with skin - Google Patents

Description

The present invention relates to a vehicle interior part with a skin, and in particular to a vehicle interior part with a skin in which a non-breathable sheet material is attached (adhered) to the surface of a base material by vacuum forming or press forming.

Conventionally, interior parts with skins have been known for vehicles, such as instrument panels, in which a highly tactile skin material consisting of a skin layer and a foam layer is attached with an adhesive or the like to the surface of a hard base material (core material) manufactured by injection molding.

When molding such interior parts with a skin, adhesive is applied to the back side (foam layer side) and then the skin material is heated and softened before being placed on the base material. Vacuum molding is then performed to adhere the skin material to the base material by drawing a vacuum through air vent holes formed through the base material, or press molding is often performed to adhere the skin material to the base material by pressing the base material and skin material together with a base material mold and a skin mold.

However, since the base material is manufactured by injection molding and has no way to escape thermal contraction during the cooling process, raised areas are likely to occur around the air vent holes. If the skin material is attached to the base material with such raised areas, the skin material will bulge locally, resulting in a poor appearance.

For example, Patent Document 1 discloses a method for integrally molding a substrate and a sheet material in which a plurality of suction grooves with a rectangular cross section are provided in parallel on the surface of the substrate, and a sheet material (skin material) is placed on the surface of the substrate so that it covers the suction grooves while pulling both sides of the sheet material, and then a vacuum is applied to the suction grooves to attach the sheet material to the substrate.

According to this patent document, by replacing suction holes (air vent holes) with multiple suction grooves, the amount of thermal contraction that occurs during injection molding of the base material is dispersed from a point to a line, making it possible to prevent localized swelling around the suction grooves, and thus preventing the skin material from swelling locally and thus causing a poor appearance.

Japanese Patent Application Publication No. 11-286050

However, the above-mentioned patent document 1 has the following problems:

In other words, in the case of Patent Document 1, the cross-sectional shape of the suction groove is rectangular, which has a relatively small removal angle when demolding, so if a relatively deep groove is formed as the suction groove, there is a risk of demolding problems occurring during injection molding of the base material.

For this reason, in the case of Patent Document 1, the suction grooves must be shallow. However, when the suction grooves are shallow, when the non-breathable covering material is attached to the substrate, the foam layer enters the shallow suction grooves, making it difficult to ensure an air passage. This causes the problem that air cannot be properly released through the air vent holes, and air accumulates between the covering material and the substrate, resulting in poor adhesion.

The present invention was made in consideration of these points, and its purpose is to provide an interior part with a skin that can prevent poor adhesion between the skin material and the base material due to air pockets during vacuum molding or press molding, while preventing demolding problems during injection molding of the base material.

To achieve the above objective, the vehicle interior part with skin according to the present invention is able to secure a relatively large draft angle, and when the skin material is attached to the base material, vertical and horizontal grooves with a V-shaped cross section that are difficult to fill with a foam layer are formed in a lattice pattern on the surface of the base material as air passages.

Specifically, the present invention is directed to a vehicle interior part with a skin, in which a skin material consisting of a skin layer and a foam layer is attached to the surface of a base material by vacuum forming or press forming.

The vehicle interior part with skin has a surface of the base material formed with a lattice pattern of a plurality of vertical grooves with a V-shaped cross section extending parallel to the mold-pulling direction during injection molding of the base material, and a plurality of horizontal grooves with a V-shaped cross section extending in a direction perpendicular to the mold-pulling direction during injection molding of the base material, and air vent holes are formed at predetermined intervals through the base material at intersections of the vertical grooves and the horizontal grooves, the groove depth of the vertical grooves is set to a depth such that the groove depth will not be filled with a foam layer when the skin material is attached, while the groove depth of the horizontal grooves is equal to or less than the groove depth of the vertical grooves, and the groove depth of the horizontal grooves having a smaller draft angle is set to be smaller than the groove depth of the horizontal grooves having a larger draft angle.

In this configuration, the vertical grooves extend parallel to the demolding direction during injection molding of the base material, so they do not create resistance to demolding during demolding, and so the groove depth can be set relatively deep. Specifically, the groove depth of the vertical grooves can be set to a depth that is not filled by the foam layer when the skin material is attached, depending on the hardness of the foam layer. Also, by forming the cross section into a V-shape, it becomes difficult for the foam layer to reach the apex of the V during vacuum molding or press molding. This combines to ensure that the relatively deep vertical grooves ensure an air passage during vacuum molding or press molding.

On the other hand, since the lateral grooves extend in a direction perpendicular to the demolding direction during injection molding of the base material, demolding resistance occurs during demolding, but by forming them in a V-shaped cross section, the demolding angle during injection molding can be made larger than that of grooves with a rectangular cross section, and the groove depth is set to a depth equal to or less than the groove depth of the vertical grooves and according to the demolding angle of the lateral grooves (the groove depth of the lateral grooves with a small draft angle is set smaller than the groove depth of the lateral grooves with a large draft angle) , so that demolding resistance during injection molding can be reduced. Also, although a relatively shallow lateral groove is easily filled with the foam layer when the skin material is attached, by forming it in a V-shaped cross section, it is difficult for the foam layer to reach the apex of the V, so a minimum air passage can be secured.

The vertical and horizontal grooves are formed in a lattice pattern, and air vent holes are formed through the intersections of the vertical and horizontal grooves. Therefore, when the skin is attached during vacuum forming or press forming, air flows into the relatively shallow horizontal grooves as the foam layer enters, and the air that flows through the horizontal grooves collects in the vertical grooves. At the same time, the air that flows through the vertical grooves, which are set to a depth such that they are not filled by the foam layer, can be reliably discharged through the air vent holes. This reliably prevents air from pooling between the non-permeable skin and the base material during vacuum forming or press forming.

As described above, the vehicle interior part with skin according to the present invention can prevent defects in demolding during injection molding of the base material, while also preventing poor adhesion between the skin material and the base material due to air pockets during vacuum molding or press molding.

1 is a cross-sectional view that illustrates a schematic view of a portion of a skin-equipped interior part of a vehicle according to an embodiment of the present invention. FIG. 2 is a diagram for explaining a typical example of vacuum forming of an interior part with a skin. FIG. 2 is a diagram for explaining a typical aspect of press molding of an interior part with a skin. FIG. 2 is a plan view illustrating a surface of a substrate. FIG. 5 is a partially enlarged view of FIG. 4 . 6A is a cross-sectional view showing a longitudinal groove and a lateral groove, FIG. 6A being a view seen from the arrow line VIa-VIa in FIG. 5, and FIG. 6B being a view seen from the arrow line VIb-VIb in FIG. FIG. 2 is a diagram for explaining a typical manner in which air escapes during vacuum molding or press molding.

The following describes how to implement the present invention with reference to the drawings.

- Overall composition of interior parts with skin -
Fig. 1 is a cross-sectional view that shows a schematic view of a part of a vehicle interior part with a skin 1 according to this embodiment. In Fig. 1, in order to make the drawing easier to see, the thicknesses of a base material 10 and a skin material 20 are exaggerated, and a vertical groove 11, a horizontal groove 13, an air vent hole 17, etc., which will be described later, are omitted. In this embodiment, an instrument panel is shown as an example of the interior part with a skin 1, but the interior part with a skin 1 is not limited to this and can be applied to interior parts of various vehicles.

As shown in FIG. 1, this interior product with skin 1 has a three-layer structure and includes a base material 10 as a core material and a skin material 20 that is attached integrally to the surface 10a of the base material 10 by vacuum forming or press forming. The base material 10 is made of resin and is injection molded using a base material molding die (not shown). The skin material 20 is a sheet material in which a skin layer 21, which is a fabric skin, and a foam layer 23 are bonded together.

In this embodiment, the skin layer 21 is made of a fabric skin, but in order to prevent ventilation stains due to dust absorption, etc., a foam layer 23 that functions as a ventilation stopper is attached to the back side of the skin layer 21, so the skin material 20 itself is a non-breathable sheet material that does not allow air to pass through.

Figure 2 is a diagram that illustrates the vacuum molding of the interior part 1 with a skin, and Figure 3 is a diagram that illustrates the press molding of the interior part 1 with a skin. Note that in Figures 2 and 3, to make the drawings easier to see, the vertical grooves 11 and horizontal grooves 13 in the base material 10 are omitted, and the skin material 20 is illustrated as a single sheet material without being divided into the skin layer 21 and the foam layer 23.

When vacuum forming the interior part with skin 1, first, as shown in FIG. 2, the base material 10 is placed on the vacuum forming mold 30. The vacuum forming mold 30 has a suction hole 30a formed therethrough so that it is concentric with the air vent hole 17 of the base material 10 when the base material 10 is set in a predetermined position.

Next, the skin material 20, whose back surface (the foam layer 23 side) is precoated with adhesive, is held by a clamping jig 31 and placed above the substrate 10 as shown by the dashed line in FIG. 2, and the skin material 20 is heated and softened by a heater (not shown).

Next, as shown by the white arrow in Figure 2, the clamp jig 31 is lowered and the skin material 20 is placed over the surface 10a of the substrate 10. Then, the vacuum pump 35 is driven and the valve 33 is opened to create a negative pressure inside the vacuum forming mold 30, and the air between the skin material 20 and the substrate 10 is sucked (vacuumed) through the air vent hole 17 and the suction hole 30a as shown by the thick arrow in Figure 2, so that the skin material 20 is tightly attached to the surface 10a of the substrate 10.

On the other hand, when press-molding the interior part with skin 1, the substrate 10 is first placed on a substrate mold 37 as shown in FIG. 3. A suction hole 37a is formed through the substrate mold 37 so that it is concentric with the air vent hole 17 of the substrate 10 when the substrate 10 is set in a predetermined position.

Then, the skin material 20, whose back surface (the foam layer 23 side) is precoated with adhesive, is held by a clamp jig 31 and placed above the substrate 10 as shown by the dashed line in FIG. 3, and the skin material 20 is heated and softened by a heater (not shown). Furthermore, a skin mold 39 is placed further above the skin material 20.

Next, as shown by the white arrow in Figure 3, the clamp jig 31 and skin mold 39 are lowered to place the skin material 20 over the surface 10a of the substrate 10, and the substrate 10 and the skin material 20 are pressed together by the substrate mold 37 and skin mold 39. As a result, the air between the skin material 20 and the substrate 10 is released to the atmosphere through the air vent hole 17 and the suction hole 37a, as shown by the dashed arrow in Figure 3, and the skin material 20 is brought into close contact with the surface 10a of the substrate 10.

When press-molding the interior part 1 with skin, a valve 33 and a vacuum pump 35 may be provided to perform suction through the air vent hole 17 and the suction hole 37a instead of opening to the atmosphere.

- Conventional problems -
However, since the base material manufactured by injection molding has no place to escape thermal contraction during the cooling process, bulges are likely to occur around the air vent holes. If a skin material is attached to the base material with such bulges, the skin material will bulge locally, resulting in a poor appearance.

One possible approach is to provide multiple suction grooves with rectangular cross sections on the surface of the base material, arranged approximately parallel to each other at a pitch of 2 to 5 mm, place the skin material on the surface of the base material so that it covers the suction grooves, and then evacuate the suction grooves to attach the skin material to the base material. In this way, by replacing the air vent holes with multiple suction grooves, the amount of thermal contraction that occurs during injection molding of the base material is dispersed from a point to a line, making it possible to prevent localized swelling around the suction grooves, thereby preventing the skin material from swelling locally and causing a poor appearance.

However, in this method, the cross-sectional shape of the suction groove is rectangular, which has a relatively small pull angle when demolding, so if a relatively deep suction groove is formed, there is a risk of demolding problems occurring during injection molding of the base material. For this reason, this method requires that the suction groove be shallow, but in the case of a shallow suction groove, when the non-breathable skin material is attached to the base material, the foam layer enters the shallow suction groove, making it difficult to ensure an air passage. This causes the problem that air does not escape well through the air vent hole, and air accumulates between the skin material and the base material, causing poor adhesion.

-Vertical and horizontal grooves-
Therefore, in the vehicle interior part 1 with skin of the present embodiment, a relatively large draft angle can be ensured, and the vertical grooves 11 and horizontal grooves 13, each having a V-shaped cross section and unlikely to be filled with the foam layer 23 when the skin material 20 is attached to the base material 10, are formed in a lattice pattern on the surface 10a of the base material 10 as air passages.

Figure 4 is a plan view showing the surface 10a of the substrate 10, and Figure 5 is a partially enlarged view of Figure 4. Figure 6 is a cross-sectional view showing the longitudinal grooves 11 and the lateral grooves 13, where (a) is a view taken along line VIa-VIa in Figure 5, and (b) is a view taken along line VIb-VIb in Figure 5. Note that in Figure 4, the groove widths Wv, Wh and pitch of the longitudinal grooves 11 and the lateral grooves 13 are exaggerated to make the figure easier to see, and air vent holes 17 and the like are omitted. The outline arrow in Figure 4 indicates the mold removal direction during injection molding of the substrate 10.

As shown in FIG. 4, a plurality of vertical grooves 11 with a V-shaped cross section that extend parallel to the demolding direction during injection molding of the substrate 10 and a plurality of horizontal grooves 13 with a V-shaped cross section that extend in a lattice pattern on the surface 10a of the substrate 10. The vertical grooves 11 and the horizontal grooves 13 are each formed at a pitch of 10 mm. In this way, by forming the vertical grooves 11 and the horizontal grooves 13 at a pitch of 10 mm, which is wider than the conventional groove pitch (2 to 5 mm), it is possible to reduce the demolding resistance during injection molding compared to conventional substrates.

As shown in FIG. 5, air vent holes 17 are formed at predetermined intervals (30 mm) at the intersections 15 between the vertical grooves 11 and the horizontal grooves 13 in the base material 10. In other words, air vent holes 17 are formed at every two intersections 15 vertically and horizontally so as to penetrate the base material 10 in the thickness direction.

The vertical grooves 11 extend parallel to the demolding direction during injection molding of the base material 10, so they do not create resistance to demolding during demolding, and the groove depth Dv can be made relatively deep. Specifically, the groove depth Dv of the vertical grooves 11 is set to a depth that is not filled by the foam layer 23 when the skin material 20 is attached, depending on the hardness of the foam layer 23.

For example, as shown in FIG. 6(b), the vertical grooves 11 in this embodiment are formed in a V-shaped cross section with a groove depth Dv = 500 (μ) and a groove width Wv:groove depth Dv = 1:1 (draft angle θv = 53 (°)), giving a relatively deep groove depth Dv and a relatively large draft angle θv. Furthermore, by forming the vertical grooves 11 in a V-shaped cross section, it becomes difficult for the foam layer 23 to reach the apex of the V during vacuum molding or press molding. Combined, the relatively deep vertical grooves 11 can reliably ensure an air passage during vacuum molding or press molding.

On the other hand, since the lateral grooves 13 extend in a direction perpendicular to the demolding direction during injection molding of the base material 10, demolding resistance occurs during demolding. However, by forming the cross section in a V-shape, the demolding angle during injection molding is made larger than that of a groove with a rectangular cross section, and the groove depth Dh of the lateral grooves 13 is set to a depth equal to or less than the groove depth Dv of the vertical grooves 11 and according to the demolding angle θh of the lateral grooves 13, specifically, to 200 to 500 (μ), thereby reducing the demolding resistance during injection molding.

More specifically, (1) in areas where demolding resistance is particularly likely to occur (e.g., areas where the release angle θh is 20 (°) or less), the groove depth Dh of the lateral grooves 13 is set to 200 (μ) (in this case, groove width Wh≦71 (μ)), and the relatively shallow groove depth Dh reduces demolding resistance during injection molding.

(2) In addition, in general areas (e.g., areas where the draft angle θh is 21° or more and less than 42°), the groove depth Dh of the lateral groove 13 is set to 300μ (in this case, 111μ≦groove width Wh<230μ) so that the relatively deep groove depth Dh reduces the demolding resistance during injection molding while ensuring an air passage during vacuum molding or press molding.

Furthermore, (3) in areas where demolding resistance is unlikely to occur (e.g., areas where the demolding angle θh is 42 (°) or more), the groove depth Dh of the lateral grooves 13 is set to 500 (μ) (in this case, 384 (μ) ≦ groove width Wh), similar to the vertical grooves 11, so that the relatively deep groove depth Dh ensures an air passage during vacuum molding or press molding.

In addition, although the relatively shallow lateral grooves 13 are easily filled with the foam layer 23 when the covering material 20 is applied, by forming the cross section in a V-shape, it is difficult for the foam layer 23 to reach the apex of the V, so a minimum air passage can be ensured.

The vertical grooves 11 and horizontal grooves 13 with a V-shaped cross section and groove widths Wv and Wh and groove depths Dv and Dh can be easily realized by subjecting the substrate molding die used for injection molding the substrate 10 to V-groove processing on its surface 10a using NC processing or special etching processing.

Figure 7 is a diagram that illustrates the manner in which air escapes during vacuum molding or press molding. The vertical grooves 11 and horizontal grooves 13 configured as described above are formed in a lattice shape, and air escape holes 17 are formed at the intersections 15 of these vertical grooves 11 and horizontal grooves 13. Therefore, when the skin material 20 is attached during vacuum molding or press molding, the foam layer 23 enters the relatively shallow horizontal grooves 13, and air flows as shown by the dashed arrows in Figure 7. The air that flows through the horizontal grooves 13 gathers in the vertical grooves 11, and the air that flows through the vertical grooves 11, which are set to a depth that is not filled by the foam layer 23, can be reliably discharged from the air escape holes 17 as shown by the thick arrows in Figure 7. This reliably prevents air from pooling between the non-permeable skin material 20 and the substrate 10 during vacuum molding or press molding.

As described above, the vehicle interior part with skin 1 according to this embodiment can ensure relatively large draft angles θv and θh, and when attaching the skin material 20 to the base material 10, the vertical grooves 11 and horizontal grooves 13, which are V-shaped in cross section and difficult to fill up to the apex of the V-shape with the foam layer 23, are formed in a lattice pattern on the surface 10a of the base material 10 as air passages. This simple configuration can prevent poor demolding during injection molding of the base material 10, while also preventing poor adhesion between the skin material 20 and the base material 10 due to air pockets during vacuum molding or press molding.

Other Embodiments
The present invention is not limited to the embodiments, and can be embodied in various other forms without departing from the spirit or main characteristics thereof.

In the above embodiment, the skin layer 21 is made of a fabric skin, but this is not limited to the above, and the skin layer 21 may be made of a skin other than a fabric skin as long as the skin material 20 itself is a non-breathable sheet material that does not allow air to pass through.

In addition, in the above embodiment, the vertical grooves 11 and the horizontal grooves 13 are each formed at a pitch of 10 mm, but this is not limiting. In order to further reduce the demolding resistance during injection molding, for example, the vertical grooves 11 and the horizontal grooves 13 may each be formed at a pitch of more than 10 mm.

In addition, in the above embodiment, the air vent holes 17 are formed at the intersections 15 at intervals of 30 mm, but this is not limited thereto. In order to further improve the ability to discharge air from the air vent holes 17 during vacuum molding or press molding, for example, the air vent holes 17 may be formed at the intersections 15 at intervals of less than 30 mm.

In addition, in the above embodiment, the groove depth Dv of the vertical grooves 11 is set to 500 (μ), but this is not limited thereto. If the foam layer 23 is soft, the groove depth Dv of the vertical grooves 11 may be set to a depth exceeding 500 (μ), and conversely, if the foam layer 23 is hard, the groove depth Dv of the vertical grooves 11 may be set to a depth less than 500 (μ).

As such, the above-described embodiments are merely illustrative in all respects and should not be interpreted in a limiting manner. Furthermore, all modifications and variations that fall within the scope of the claims are within the scope of the present invention.

The present invention can prevent poor adhesion between the skin material and the substrate due to air pockets during vacuum or press molding while preventing defects in demolding during injection molding of the substrate, making it extremely useful for use in vehicle interior parts with skin, in which the skin material, which is a non-breathable sheet material, is attached to the surface of the substrate by vacuum or press molding.

1 Interior product with skin 10 Base material 10a Surface 11 Longitudinal groove 13 Horizontal groove 15 Intersection 17 Air vent hole 20 Skin material 21 Skin layer 23 Foam layer Dh Groove depth Dv of horizontal groove Groove depth θh of vertical groove Draft angle of horizontal groove

Claims (1)

A skin-attached interior part for a vehicle, in which a skin material consisting of a skin layer and a foam layer is attached to a surface of a base material by vacuum forming or press forming,
a surface of the substrate is formed with a lattice pattern of a plurality of vertical grooves having a V-shaped cross section and extending parallel to a mold-pulling direction during injection molding of the substrate, and a plurality of horizontal grooves having a V-shaped cross section and extending in a direction perpendicular to the mold-pulling direction during injection molding of the substrate, and air vent holes are formed at predetermined intervals at intersections of the vertical grooves and the horizontal grooves in the substrate;
The depth of the longitudinal grooves is set so that they will not be filled by the foam layer when the skin is attached.
The groove depth of the lateral groove is equal to or less than the groove depth of the longitudinal groove, and the groove depth of the lateral groove having a smaller draft angle is set smaller than the groove depth of the lateral groove having a larger draft angle.

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