Integral skin foam molded article

Abstract: A core 3 is formed with an accommodating recess 9 for accommodating a foamed layer 7 . An erected wall 11 of the core 3 around the accommodating recess 9 is formed at its intermediate position with a core side step 13 so that a bottom side portion of the accommodating recess 9 is narrower than an opening side portion thereof. A skin 5 has a peripheral erected part 17 covering the foamed layer 7 . The peripheral erected part 17 of the skin 5 is formed at its intermediate position with a skin side step 19 that is located closer to the opening of the accommodating recess 9 than the core side step 13 and that is bent toward inside of the accommodating recess 9 . An opening side portion 17a of the peripheral erected part 17 closer to the opening of the accommodating recess 9 than the skin side step 19 is pressed against an opening side portion 11a of the erected wall 11 closer to the opening of the accommodating recess 9 than the core side step 13 . And a bottom side portion 17b of the peripheral erected part 17 closer to the bottom of the accommodating recess 9 than the skin side step 19 is pressed against a bottom side portion 11b of the erected wall 11 closer to the bottom of the accommodating recess 9 than the core side step 13 . As a result, an integral skin foam molded article with sealing properties obtains a structure that the skin 5 can be easily demolded after slush molded.

Description: BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention generally relates to an integral skin foam molded article, in which a foamed layer is formed between and integrally with a core and a skin. 2. DESCRIPTION OF THE PRIOR ART The present applicant has already filed a patent application for an integral skin foam molded article as disclosed in Japanese Unexamined Patent Publication No. 2000-6283. In the article according to the invention of this patent application, a core is formed with an accommodating recess for accommodating a foamed layer. An erected wall of the core located around the accommodating recess is formed at its intermediate position with a step such that a bottom side portion of the accommodating recess is narrower than an opening side portion of the accommodating recess. A skin has a peripheral erected part bent from the circumference to the back of its main part. And the peripheral erected part of the skin is pressed against a portion of the erected wall located to surround the bottom side portion of the accommodating recess bounded by the step. Thus, the sealing properties of the article are ensured to prevent a foaming resin material from leaking to the surface side of the skin main part, thereby improving the appearance of the article. Furthermore, according to the invention of this patent application, a peripheral narrow groove is opened in the skin peripheral erected part so as to be opposite to the step of the erected wall. Thus, the foaming resin material having penetrated between the skin peripheral erected part and the erected wall will be stored in the peripheral narrow groove. Also in this manner, the foaming resin material is prevented from leaking to the surface side of the skin main part, thereby improving the appearance of the article. Also, the presence of this peripheral narrow groove improves the stiffness of the skin peripheral erected part, thereby preventing waving of the skin which causes the leakage of the material. If the skin is formed by slush molding, in order to form the above-described peripheral narrow groove in the skin peripheral erected part, a peripheral narrow protrusion for forming a peripheral narrow groove has to be provided in a slush mold. In this case, when the skin is demolded after the molding has been finished, the peripheral narrow groove portion of the skin peripheral erected part should be taken out of the peripheral narrow protrusion. However, since the peripheral narrow protrusion is stuck in the peripheral narrow groove, it is hard to take the peripheral narrow groove portion of the skin peripheral erected part out of the peripheral narrow protrusion. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an integral skin foam molded article with sealing properties described above which has an easily demoldable skin structure even for the slush molded skin. This object is achieved with an integral skin foam molded article having the features of claim 1. Preferable embodiments form the subject matter of subclaims. In the structure according to the invention, the skin side step formed in the peripheral erected part of the skin provides a level difference in a direction from inside to outside of the accommodating recess because of the positional relationship between the opening side peripheral erected portion and the bottom side peripheral erected portion. Therefore when the skin is formed by slush molding, no peripheral narrow protrusion for forming a peripheral narrow groove is needed unlike the prior art and it can be avoided that the skin is hard to demold because the peripheral narrow protrusion gets stuck in the peripheral narrow groove. Accordingly, the skin can be smoothly demolded with small resistance. Furthermore, since the opening side peripheral erected portion of the peripheral erected part of the skin is pressed against the opening side erected wall portion of the erected wall, while the bottom side peripheral erected portion of the peripheral erected part of the skin is pressed against the bottom side erected wall portion of the erected wall, a dual sealing structure can be obtained to prevent a foaming resin material from leaking to the surface side of the main part of the skin, thereby improving the appearance of the integral skin foam molded article. Moreover, the skin side step increases the stiffness of the peripheral erected part of the skin, thereby preventing waving of the skin which causes the leakage of the foaming resin material. In the structure according to the invention, the skin can be positioned at a right location as a result of the pressing of the skin side step against the core side step. Accordingly, the boundary between the core and the skin can be defined well, thus improving the appearance of the integral skin foam molded article. Furthermore, the existence of the skin side step and the core side step can increase the contact area between the peripheral erected part of the skin and the erected wall of the core. As a result, the sealing properties of the article can be further improved. The invention of Claim 2 is based on the invention of Claim 1 and characterized in that, in the vicinity of a corner at which the bottom side peripheral erected portion of the peripheral erected part of the skin intersects with the skin side step, a thin hinge part is formed for facilitating leaning of the bottom side peripheral erected portion against the bottom side erected wall portion of the erected wall of the core. In this embodiment of the invention, the foaming pressure during the molding allows the bottom side peripheral erected portion of the peripheral erected part of the skin to lean against the bottom side erected wall portion by action of the thin hinge part as a fulcrum and to be thereby pressed against it. Thus, the bottom side peripheral erected portion of the skin tightly engages the bottom side erected wall portion with certainty. As a result, the sealing properties of the article can be further improved. The invention of Claim 3 is based on the invention of Claim 1 and characterized in that the core side step has a depression that is opened to face the skin side step. In this embodiment of the invention, even if the foaming resin material penetrates between the bottom side erected wall portion of the erected wall and the bottom side peripheral erected portion of the peripheral erected part of the skin and further reaches between the core side step and the skin side step, the foaming resin material is stored in the depression formed in the core side step, thereby preventing the foaming resin material from leaking to the surface side of the skin main part. As a result, the sealing properties of the article are further improved. Moreover, the depression is opened to the direction in which the core is demolded, and thus under cut will not be created. Accordingly, the mold needs no slide core to form the depression, thus reducing the cost of the mold. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an instrument panel as an integral skin foam molded article according to EMBODIMENT 1 of the present invention and is a cross-sectional view taken along the line A-A shown in FIG. 6 . FIG. 2 illustrates an instrument panel as an integral skin foam molded article not according to the present invention and is a cross-sectional view taken along the line A-A shown in FIG. 6 . FIG. 3 illustrates an instrument panel as an integral skin foam molded article according to EMBODIMENT 2 of the present invention and is a cross-sectional view taken along the line A-A shown in FIG. 6. FIG. 4 is an enlarged cross-sectional view illustrating part of an instrument panel where the core side step and the skin side step overlap in MODIFIED EXAMPLE 1. FIG. 5 is an enlarged cross-sectional view of a panel not according to the present invention and illustrating part of an instrument panel where the core side step and the skin side step overlap modified from the panel of Fig. 2. FIG. 6 is a perspective view illustrating an instrument panel as an integral skin foam molded article. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 6 illustrates an instrument panel 1 that is an automotive interior trim article as an integral skin foam molded article. This instrument panel 1 includes a core 3 , a skin 5 , and a foamed layer 7 (shown in FIGS. 1 through 5 ) that is formed between and integrally with the core 3 and the skin 5 . In this exemplary embodiment, the skin 5 is provided substantially in the entire upper panel part of the instrument panel 1 , and the core 3 is exposed in the other part in which the skin 5 is not provided. These core 3 , skin 5 , and foamed layer 7 are made of resin that has been well known and widely used in the prior art. Examples of the resin include thermo plastic olefin (TPO) for the core 3 , olefin resin for the skin 5 which is subjected to slush molding to form a flexible skin, and polyurethane foam for the foamed layer 7 . Also, the instrument panel 1 is molded, for example, as follows. First, the skin 5 that has been slush molded in advance is set in a lower mold member of a mold, while the core 3 that has been injection molded in advance is set in an upper mold member of the mold. Next, before or after the upper and lower mold members are clamped, foamable polyurethane resin material is injected into a cavity defined by the upper and lower mold members. Then, the injected resin material is foamed and cured so that the foamed layer 7 is formed between and integrally with the core 3 and the skin 5 . FIG. 1 is a cross-sectional view taken along the line A-A shown in FIG. 6 and shows the feature of an integral skin foam molded article according to EMBODIMENT 1 of the present invention. Specifically, the core 3 is formed with an accommodating recess 9 , which is opened to correspond to the region where the skin 5 is formed, for accommodating the foamed layer 7 . A peripheral wall of this accommodating recess 9 constitutes an erected wall 11 , and the erected wall 11 surrounds the foamed layer 7 . The erected wall 11 is formed, at an intermediate position thereof in the depth direction of the accommodating recess 9 , with a core side step 13 so that a portion of the accommodating recess 9 closer to the bottom thereof than the core side step 13 is narrower than a portion of the accommodating recess 9 closer to the opening thereof than the core side step 13 . On the other hand, the skin 5 includes a main part 15 that covers the opening of the accommodating recess 9 , and a peripheral erected part 17 that is formed integrally with the main part 15 to bend from the circumference to the back of the main part 15 and engage the inner periphery of the erected wall 11 . The peripheral erected part 17 of the skin is formed, at an intermediate position thereof in the depth direction of the accommodating recess 9 , with a skin side step 19 that is located closer to the opening of the accommodating recess 9 than the core side step 13 of the erected wall 11 and that is bent toward inside of the accommodating recess 9 . Further, an opening side peripheral erected portion 17a of the peripheral erected part 17 of the skin 5 located closer to the opening of the accommodating recess 9 than the skin side step 19 is pressed against an opening side erected wall portion 11a of the erected wall 11 located closer to the opening of the accommodating recess 9 than the core side step 13 , while a bottom side peripheral erected portion 17b of the peripheral erected part 17 of the skin 5 located closer to the bottom of the accommodating recess 9 than the skin side step 19 is pressed against a bottom side erected wall portion 11b of the erected wall 11 located closer to the bottom of the accommodating recess 9 than the core side step 13. Furthermore, the skin side step 19 is pressed against the core side step 13 . The foaming pressure of the foaming resin material during the molding of the foamed layer 7 allows the above-described pressing. Accordingly, also in the article in which the foaming resin material has been foamed and cured, the condition of the pressing is still maintained. Furthermore, the tip of the bottom side peripheral erected portion 17b of the peripheral erected part 17 of the skin 5 does not reach the bottom face of the accommodating recess 9, thus forming a gap therebetween. Therefore in molding the foamed layer 7 , air resulting from the foaming of the foaming resin material is discharged outside from between the bottom side peripheral erected portion 17b and the bottom side erected wall portion 11b. Accordingly, the erected wall 11 of the core 3 and the peripheral erected part 17 of the skin 5 can be sealed at two places, i.e., on both sides of the boundary defined by the core side step 13 and the skin side step 19 . And this dual sealing structure can prevent the foaming resin material from leaking to the surface side of the main part 15 of the skin 5 , thereby forming the instrument panel 1 of good appearance. Also, since the skin side step 19 is pressed against the core side step 13 , the skin 5 can be positioned at a right location. Accordingly, the boundary L between the core 3 and the skin 5 can be defined well, thus improving the appearance of the instrument panel 1 . Furthermore, the existence of the skin side step 19 and the core side step 13 can increase the contact area between the peripheral erected part 17 of the skin 5 and the erected wall 11 of the core 3 , thereby further improving the sealing properties of the article. Besides, the existence of the skin side step 19 can increase the stiffness of the peripheral erected part 17 of the skin 5 , thereby preventing waving of the peripheral erected part 17 of the skin 5 which causes the leakage of the material. Moreover, the skin side step 19 formed in the peripheral erected part 17 of the skin 5 provides a level difference in a direction from inside to outside of the accommodating recess 9 because of the positional relationship between the opening side peripheral erected portion 17a and the bottom side peripheral erected portion 17b . Thus, even if the skin 5 is slush molded, it can be avoided unlike the prior art example that the skin 5 is hard to demold because the peripheral narrow protrusion for forming the peripheral narrow groove gets stuck in the peripheral narrow groove. Consequently, the skin 5 can be smoothly demolded with small resistance. FIG. 2 is a cross-sectional view taken along the line A-A shown in FIG. 6 like EMBODIMENT 1 of the invention and shows a feature of an integral skin foam molded article not according to the invention. A gap 21 of rectangular cross section is formed between the skin side step 19 and the core side step 13 to take the shape of a ring around the entire periphery of the peripheral erected part 17 of the skin 5 . Other than this feature, the instrument panel 1 is formed in the same way as EMBODIMENT 1 of the invention. Therefore the same constituent members are identified by the same reference characters as those used in EMBODIMENT 1 and the detailed description thereof will be omitted. FIG. 3 is also a cross-sectional view taken along the line A-A shown in FIG. 6 like EMBODIMENT 1 and shows the feature of an integral skin foam molded article according to EMBODIMENT 2 of the present invention. In EMBODIMENT 2, the core side step 13 has depressions 23 that are opened to face the skin side step 19 and are rectangular in cross section. The depressions 23 are formed to take the shape of a ring around the entire periphery of the peripheral erected part 17 of the skin 5 in an intermittent manner with each partition wall 25 interposed between the adjacent depressions 23 . Alternatively, instead of forming the partition walls 25 , a continuous depression 23 may be formed. The skin side step 19 is pressed against the core side step 13 like EMBODIMENT 1. The same constituent members are identified by the same reference characters as in EMBODIMENT 1 and the detailed description thereof will be omitted. Accordingly, in EMBODIMENT 2, the same effects as in EMBODIMENT 1 are attainable. Furthermore, in EMBODIMENT 2, even if the foaming resin material penetrates between the bottom side erected wall portion 11b of the erected wall 11 and the bottom side peripheral erected portion 17b of the peripheral erected part 17 and further reaches between the core side step 13 and the skin side step 19 , the foaming resin material is stored in the depressions 23 formed in the core side step 13, thereby further improving the sealing properties of the instrument panel 1 . Moreover, the depressions 23 are opened to the direction in which the core 3 is demolded, and thus under cut will not be created. Accordingly, the mold needs no slide core to form the depressions 23 , thus reducing the cost of the mold. FIG. 4 is an enlarged cross-sectional view illustrating part of an instrument panel where the core side step 13 and the skin side step 19 overlap in MODIFIED EXAMPLE 1. In MODIFIED EXAMPLE 1, in a corner 17c at which the bottom side peripheral erected portion 17b of the peripheral erected part 17 of the skin 5 intersects with the skin side step 19 , a thin hinge part 27 is formed for facilitating leaning of the bottom side peripheral erected portion 17b against the bottom side erected wall portion 11b of the erected wall 11 of the core 3. Other than this feature, the instrument panel 1 is formed in the same way as EMBODIMENT 1. Therefore the same constituent members are identified by the same reference characters as those used in EMBODIMENT 1 and the detailed description thereof will be omitted. The foaming pressure of the foaming resin material during the molding of the foamed layer 7 allows the leaning of the bottom side peripheral erected portion 17b . The corner 17c is formed during the molding of the skin 5 . It should be noted that the thin hinge part 27 may be formed slightly away from the corner 17c and slightly closer to the bottom side peripheral erected portion 17b than the position shown in FIG. 4. Moreover, the skin 5 formed with the thin hinge part 27 may also be applicable to EMBODIMENT 2. Accordingly, in MODIFIED EXAMPLE 1, the same effects as in EMBODIMENT 1 are attainable. Furthermore, in MODIFIED EXAMPLE 1, the foaming pressure during the molding allows the bottom side peripheral erected portion 17b of the peripheral erected part 17 of the skin 5 to easily lean against the bottom side erected wall portion 11b of the core 3 by action of the thin hinge part 27 as a fulcrum and to be thereby pressed against it. Thus, the bottom side peripheral erected portion 17b tightly engages the bottom side erected wall portion 11b with certainty. As a result, the sealing properties of the instrument panel 1 can be further improved. FIG. 5 is an enlarged cross-sectional view illustrating part of an instrument panel where the core side step 13 and the skin side step 19 overlap. The panel of Fig. 5 shows a feature not according to the invention. The core side step 13 is formed to provide a surface which inclines downwardly inwards the accommodating recess 9 so that a gap 21 of triangular cross section is formed between the core side step 13 and the skin side step 19 although its shape differs from that of the gap 21 illustrated in FIG. 2 . Other than this feature, the instrument panel 1 is formed in the same way as EMBODIMENT 1. Therefore the same constituent members are identified by the same reference characters as those used in EMBODIMENT 1 and the detailed description thereof will be omitted. Although each of the foregoing embodiments and modified example has been described on the supposition that the integral skin foam molded article is the instrument panel 1 as an automotive interior trim article, the inventive integral skin foam molded article may be applied to any other molded article for door trim or trim other than automotive interior trim.

Claims: An integral skin foam molded article comprising a core (3), a skin (5), a foamed layer (7) formed between and integrally with the core and the skin, the core being formed with an erected wall (11) constituting an accommodating recess (9) which accommodates the foamed layer, the accommodating recess being opened to correspond to a region where the skin is formed, and the skin including a main part (15) that covers an opening of the accommodating recess, and a peripheral erected part (17) that is formed integrally with the main part to bend from the circumference to the back of the main part and engage an inner periphery of the erected wall (11), wherein the erected wall (11) of the core (3) is formed at an intermediate position thereof with a core side step (13) extending perpendicularly to the inner surface of the erected wall (11) so that a portion of the accommodating recess (9) closer to the bottom thereof than the core side step (13) is narrower than a portion of the accommodating recess closer to the opening thereof than the core side step, wherein the peripheral erected part (17) of the skin (5) is formed at an intermediate position thereof with a skin side step (19) bending toward inside of the accommodating recess (9), and wherein an opening side peripheral erected portion (17a) of the peripheral erected part (17) of the skin (5) located closer to the opening of the accommodating recess (9) than the skin side step (13) is pressed against an opening side erected wall portion (11a) of the erected wall (11) located closer to the opening of the accommodating recess (9) than the core side step (13), while a bottom side peripheral erected portion (17b) of the peripheral erected part (17) of the skin (5) located closer to the bottom of the accommodating recess (9) than the skin side step (19) is pressed against a bottom side erected wall portion (11b) of the erected wall (11) located closer to the bottom of the accommodating recess (9) than the core side step (13), characterized in that the skin side step (19) of the peripheral erected part (17) of the skin (5) is in contact with the core side step (13) of the erected wall (11) of the opening of the accommodating recess (9), extends perpendicularly to the peripheral erected part (17) of the skin (5), and is pressed against the core side step (19). The integral skin foam molded article of claim 1, wherein in the vicinity of a corner at which the bottom side peripheral erected portion (17b) of the peripheral erected part (17) of the skin (5) intersects with the skin side step (19), a thin hinge part (27) is formed for facilitating leaning of the bottom side peripheral erected portion (17b) against the bottom side erected wall portion (11b) of the erected wall (11) of the core (3). The integral skin foam molded article of claim 1, wherein the core side step (13) has a depression that is opened to face the skin side step (19).

Inventors: IMAI HIDEKI, KAWANOUE SHIGENORI, SHIMABARA TETSUO, YANAGISAWA KIYOTAKA, IMAI, HIDEKI, KAWANOUE, SHIGENORI, SHIMABARA, TETSUO, YANAGISAWA, KIYOTAKA, Imai, Hideki, c/o Nishikawa Kasei Co.,Ltd., Kawanoue, Shigenori, c/o Nishikawa Kasei Co.,Ltd., Shimabara, Tetsuo, c/o Nishikawa Kasei Co.,Ltd., Yanagisawa, Kiyotaka, c/o Nishikawa Kasei Co.,Ltd.
Applicants: NISHIKAWA KASEI KK, NISHIKAWA KASEI CO., LTD.
Application year: 2001
Main classification: B29C44
IPC codes: B29C39, B29K105, B60K37, B29C44, B29L9