Cushion pad and manufacturing method thereof

Abstract

To provide a cushion pad capable of greatly progressing weight saving of a bead foam molding member, while retaining necessary strength and rigidity, and manufacturing method thereof.SOLUTION: A cushion pad comprises a core pad 1 including a hole opening 1d on a lower surface of a block-like bead foam molding body to provide a recessed hole 12 recessed toward a top face 1a side of the bead foam molding body, a lid member 2 closing a hole opening 120 so as to form an enclosure space S along with a hole wall 121 of the recessed hole 12 and attached and fixed to the core pad 1, and a surface layer pad 6 of a soft polyurethane foam molding body forming a seating surface part 61 and laminated to cover the top face 1a and a side face 1b of the core pad 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cushion pad that forms a seat portion of a seat and a method for manufacturing the same. [Background technology]

[0002] For example, the backrest of a seat pad installed in a vehicle such as an automobile is formed from a back pad, and the seat portion is formed from a cushion pad. As for cushion pads, in recent years, there has been a growing trend to replace the back side with a core pad made of expanded polypropylene, expanded styrene, etc., as a measure to reduce weight. In addition, a bead foam molding member has been proposed to further reduce the weight of this core pad (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2020-82992 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] However, the bead foam molding member of Patent Document 1 has a plurality of cylindrical lightening holes with bottoms provided from the surface opposite the seating surface toward the seating surface, but as shown in Fig. 5, the back surface 22 may become perforated with a plurality of openings 2e1, which may make it difficult to set the bead foam molding member in the foam molding die for the cushion pad. The bead foam molding member shrinks during molding and dimensional accuracy cannot be improved, so the back surface is likely to become irregularly uneven, making it difficult to set it in the upper die during foam molding of the cushion pad. In addition, in the foamed bead molded member of Patent Document 1, if the lightening holes are simply made too many or large, the strength and rigidity will decrease, so a significant proportion of the surrounding foamed bead molded member, including the inner walls that form the lightening holes, must be left intact. There is also a certain limit to how much weight can be reduced.

[0005] The present invention is devised to solve the above-mentioned problems, and aims to provide a cushion pad and a manufacturing method thereof that can greatly advance the weight reduction of bead foam molded components while maintaining the necessary strength and rigidity. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the gist of the present invention is a cushion pad comprising: a core pad having an opening on the underside of a block-shaped bead foam molding and a recessed hole that recesses toward the upper surface of the bead foam molding; a cover member that is attached and fixed to the core pad and covers the opening so that an enclosed space is formed by the hole wall of the recessed hole; and a surface pad of a soft polyurethane foam molding that forms a seating surface and is laminated to cover the upper and side surfaces of the core pad.

[0007] In the case of the cushion pad of the present invention, a core pad is provided with a hole on the underside of the block-shaped bead foam molding and a recessed hole that is recessed toward the upper side of the bead foam molding, and the volume of the recessed hole becomes a void, making it possible to reduce the weight. On the other hand, if a large recessed hole is provided, there is a risk that the strength of the core pad will decrease and the periphery of the recessed hole will be damaged, but if a cover member is attached and fixed to the core pad so that the hole opening forms an enclosed space with the hole wall of the recessed hole, the cover member reinforces the area around the hole opening, and therefore it is possible to effectively prevent the strength of the core pad from decreasing and the periphery of the recessed hole from being damaged. Effect of the Invention

[0008] The cushion pad and its manufacturing method of the present invention have excellent effects, such as significantly reducing weight by forming a recessed hole in the core pad of the bead foam molding, ensuring the necessary strength and rigidity by providing a lid member, and further reducing the material costs of the bead foam molding by forming the recessed hole. [Brief description of the drawings]

[0009] [Figure 1]FIG. 2 is an exploded perspective view of the cushion pad as viewed from the back surface side, in one embodiment of the cushion pad and the manufacturing method thereof according to the present invention. [Diagram 2] 2 is a perspective view of the cushion pad with the hole opening of the core pad covered with the lid body of FIG. 1. FIG. [Diagram 3] 3 is a schematic cross-sectional view of the left half of the cross-sectional view taken along line III-III in FIG. 1 and of the left-side cover main body. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] This is a cross-sectional view showing how a core pad is set in the upper mold and foaming raw material is injected into the lower mold. [Figure 6] FIG. [Figure 7] FIG. 2 is an explanatory cross-sectional view of a surface pad integral with a core pad, which has been foam-molded. [Figure 8] 8 is a partial cross-sectional view of a cushion pad in which a cover member is attached and fixed to the core pad-integrated surface layer pad of FIG. 7. [Figure 9] 5 is a view showing a cushion pad cover with a member to be locked, and shows another embodiment, which is an alternative to FIG. 4, in which the clip shown in FIG. 4 is eliminated and the locking portion is replaced with a receiving groove portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The cushion pad and the manufacturing method thereof according to the present invention will be described in detail below. Figures 1 to 9 show one embodiment of the cushion pad and the manufacturing method thereof according to the present invention, in which Figure 1 is an exploded perspective view of the cushion pad, Figure 2 is a perspective view of the cushion pad, Figure 3 is a partial cross-sectional view of the core pad integrated surface layer pad and the lid body, Figure 4 is a cross-sectional view along the line IV-IV in Figure 2, Figure 5 is a cross-sectional view of the foaming raw material being injected into the lower mold after the core pad is set in the upper mold, Figure 6 is a cross-sectional view of the mold being closed, Figure 7 is a cross-sectional view of the surface layer pad integrated with the core pad foam-molded, Figure 8 is a cross-sectional view of the cushion pad in which the lid member is fixed to the core pad integrated surface layer pad in Figure 7, and Figure 9 is a view of another embodiment in which the locking portion is a receiving groove portion. Each figure is simplified to make the drawings easier to understand, and parts that are not directly related to the present invention are omitted. Also, the cushion pad in Figure 4 is shown with the upper surface side when installed in a vehicle facing downward on the paper, and the cushion pads in Figures 5 to 9 are molded upside down.

[0011] The cushion pad P is a seat pad that supports the lower body of a seated person, and this embodiment is applied to the cushion pad P of a vehicle rear seat (Figs. 1 to 8). If the cushion pad P is covered with a cushion pad cover T to form a seat cushion, a rear seat with an auxiliary seat portion 6C added to the center in the vehicle width direction is formed together with a seat back in which a back pad cover is covered on a known back pad. Fig. 2 is a perspective view of the cushion pad P as seen from below, with the upper left diagonally upward from the paper being the front of the vehicle. The cushion pad P includes a core pad 1, a cover member 2, and a surface pad 6.

[0012] The core pad 1 is a bead foam molded into a block shape as shown in Figures 1 and 7, and is a foam molded body for raising the height, occupying approximately the lower half of the cushion pad P. The core pad 1, which is foam molded using expanded polypropylene, expanded polystyrene, or a composite material of these, is lighter, harder, and has better shape retention than the cushioned surface pad 6. However, it has the disadvantage that it suffers from large molding shrinkage and large dimensional errors. To eliminate this disadvantage, the core pad 1 is divided into two in the longitudinal direction of the vehicle width to reduce dimensional errors.

[0013] The core pad 1 has a hole opening 120 on the lower surface 1d of the bead foam molding, and a recessed hole 12 is formed that recesses toward the upper surface 1a of the bead foam molding. The side surface 1b of the core pad is covered by the peripheral layer 62 of the surface pad 6, but the core pad 1 occupies almost the entire lower surface of the cushion pad P. The recessed hole 12 can be a large hole as shown in FIG. 1, which is carved out from the lower surface 1d of the core pad 1 toward the upper surface 1a. Even if the core pad 1 has a large bowl-shaped recessed hole 12, the cover member 2 that covers the hole opening 120 forms an enclosed space S and is integrated with the core pad 1 to reinforce the core pad 1, ensuring the necessary strength. In this embodiment, the core pad 1 is formed with a recessed hole 12 carved into a quadrangular pyramid shape from the lower surface of a substantially rectangular body that becomes the core pad lower surface 1d, and further, a rectangular recess 13 is provided at the hole bottom 1211 of the recessed hole 12. A step surface 11 is formed on the periphery of a hole opening 120 that extends from the core pad lower surface 1d toward the hole bottom 1211. When the outer peripheral thickness t2 of the cover member 2 is matched to the height of the step wall 11b and the hole opening 120 is closed with the cover member 2 to form the cushion pad of FIG. 2, the outer surface 2d of the cover member 2 becomes approximately flush with the core pad lower surface 1d.

[0014] The lid member 2 is a plate-like body that closes the hole opening 120 so that an enclosed space S is formed together with the hole wall 121 of the recessed hole 12, and is attached and held to the core pad 1. The hole opening 120 does not need to be closed in an airtight manner, and it is sufficient that the enclosed space S is formed by covering the recessed hole 12 with the lid member 2 as shown in FIG.

[0015] Here, the lid member 2 has a pillar portion 21 (or / and a plate-shaped wall portion) protruding from the inner lid surface 2a, and when the lid member 2 closes the hole opening 120, the tip portion 211 of the pillar portion 21 (or / and the wall portion) fits into and engages with the recess 13 provided in the hole bottom 1211 of the recessed hole 12. In detail, a column 21 with a rectangular cross section stands on the inner surface 2a of the cover body 2A of the square plate, and when the cover member 2 covers the recessed hole 12, the tip portion 211 of the column 21 is inserted into the recess 13 and locked. The column 21 is fixed by inserting the column tip portion 211, which corresponds to the tenon, into the mortise recess 13. The thickness t21 of the column 21 is made larger than the opening width W13 of the recess 13, and is made slightly larger so that an interference portion 5 (see FIG. 8) is formed at the tapered tip portion 211, and the column tip portion 211 is fitted and locked into the recess 13 while elastically deforming the core pad 1 of the bead foam molded body around the recess 13. This promotes integration with the core pad 1 when the cover member 2 itself closes the hole opening 120. In this embodiment, the cover member 2 is also made of a bead foam molding similar to the core pad 1, and in addition to being lightweight, the column tip portion 211 can be elastically deformed to fit and engage with the recess 13, and when the cover member 2 closes the hole opening 120, it has an elastic reaction force, making the integration strong. In addition, the column portion 21 supports the hole bottom 1211 of the core pad 1 to increase the load-bearing strength, making it possible to form a large recessed hole 12 in the core pad 1. Although the pillar portion 21 is used here, it may be replaced by, for example, a plate-shaped wall portion, which acts as a partition wall dividing the enclosed space S into two rooms.

[0016] In addition, a locking portion 4 for locking an end of the cushion pad cover T is provided on the outer cover surface 2d of the cover member 2. In FIG. 2 in which the cover member 2 covers the hole opening 120 of the core pad 1 with the surface pad 6, a plurality of accommodation grooves 22 for locking the end of the cushion pad cover T are formed on the outer cover surface 2d along the outer periphery of the cushion pad P. A clip is held in the accommodation groove 22 as the locking portion 4 for locking the locked member K attached to the end of the cushion pad cover T. The clip 4 here is a resin molded product that is molded as an insert product integrally when the cover member 2 having the accommodation groove 22 is molded, and has a pair of standing pieces 42 standing apart from each other from a base portion 41, and a hook portion 43 that projects toward the opposing standing piece 42 is formed at the tip of each of the standing pieces 42. The clip 4, which becomes the locking part, has a uniform cross-sectional shape in the longitudinal direction, and has a base part 41 disposed in the accommodation groove 22, with two branched standing pieces 42 each extending upward in the accommodation groove 22 and bending at a tip part 211 to the opposing standing piece 42, forming a hook part 43 (Figs. 3 and 4). A locked member K, for example, having an arrowhead shape, is attached to the end of the cushion pad cover T. The locked member K is inserted between the hook parts 43 while elastically deforming the standing piece 42, and is locked by the clip 4, so that the cushion pad P can be covered with the cushion pad cover T to form a seat cushion. Incidentally, in Figures 1 and 2, the outer surface 2d of the cover member other than the accommodating groove portion 22 is simply illustrated as flat, but in reality the outer surface 2d of the cover member has an uneven shape that matches the surface shape of the vehicle body side on which the seat cushion is installed.

[0017] The surface pad 6 is a soft polyurethane foam molded body that forms a seating surface portion 61 and is laminated to cover the upper surface 1a and side surface 1b of the core pad 1. The surface pad 6 is molded integrally with the underlying core pad 1, and the surface pad 6 exposes the lower surface 1d of the core pad and covers all surfaces of the core pad 1 except the lower surface 1d. The surface pad 6 here is molded integrally with two core pads 1 set in an upper mold 8 described later, and has the seating surface portion 61 on which a seated person sits, a side peripheral layer 62 surrounding the outer peripheral side surface of the two aligned core pads 1, and a filling layer 65 filling the space between the two core pads 1. The cover member 2 is attached to the surface pad 6 molded integrally with the core pad 1 as shown in FIG. 1, closing the hole 120, to form the desired cushion pad P. Furthermore, the accommodating groove portion 22 is arranged along the outer peripheral edge of the lid member 2, and at the portion along the outer peripheral edge excluding the accommodating groove portion 22, the lid member 2 is fixed to the core pad 1 by screws V or the like (Figure 8), and the lid member 2 and the surface pad 6 with the core pad 1 are integrally reinforced to form the desired cushion pad P. Reference numeral 6A denotes a main portion, reference numeral 6B denotes a side portion, reference numeral 20 denotes a recess, and reference numeral 69 denotes a hanging groove formed on the upper surface side of the surface pad 6.

[0018] The present invention is not limited to the above-mentioned embodiment, and many modifications are possible within the technical concept of the present invention. The cushion pad P is not limited to the cushion pad P shown in Figs. 1 to 8, and may be, for example, a cushion pad P as shown in Fig. 9. The cushion pad P in Fig. 9 is provided with a storage groove 22 that becomes the locking portion 4, and a locked member K that is larger than the groove width of the storage groove 22 and interferes with the storage groove 22 is attached to the end of the cushion pad cover T. The locked member K is inserted into the storage groove 22 by elastically deforming or cutting the groove side wall of the storage groove 22, and the locked member K is fitted and locked into the storage groove 22 that becomes the locking portion 4.

[0019] Such a cushion pad P is manufactured, for example, by the following manufacturing method (Figs. 5 to 8). A foam molding die 7 and the core pad 1 are prepared, and in the first step, the core pad 1 is set in the foam molding die 7. After that, polyurethane raw material g is injected and the die is closed to form a surface pad 6 with the core pad 1, in which the opening 120 of the recessed hole 12 is opened (Figs. 1 and 7). Then, in the second step, the opening 120 of the recessed hole 12 is covered with the cover member 2 (Figs. 2 and 8), to produce the cushion pad P. The foam molding mold 7 is a split mold as shown in Fig. 5, and includes an upper mold 8 as one mold and a lower mold 9 as the other mold. When the molds are closed as shown in Fig. 6, the cavity C of the cushion pad P is formed by the lower mold cavity surface 91, which is generally highly concave, and the upper mold cavity surface 81, which is substantially flat.

[0020] More specifically, in the first step, with the mold open, the underside 1d of the core pad 1 is placed against the upper mold 8, and the core pad 1 is set so as to close the hole opening 120 (FIG. 5). After the core pad 1 is attached and set on a set pin (not shown) provided on the upper mold cavity surface 81, the polyurethane raw material g is injected onto the lower mold cavity surface 91. Next, the foam molding die 7 is closed to form a cavity C for the cushion pad P into which the core pad 1 is insert-set (FIG. 6). Here, the die is closed after the polyurethane raw material g is injected, but the polyurethane raw material g can also be injected after the die is closed. Next, the surface pad 6 is formed by foaming and curing the polyurethane raw material g in the cavity C (FIG. 7). The surface pad 6 thus formed becomes the surface pad 6 with the core pad 1 integrated therewith, and this is removed from the mold to complete the first step.

[0021] Thereafter, in the second step, the hole opening 120 of the core pad 1 relating to the surface pad 6 with the core pad 1 is covered with the cover member 2 to produce the desired cushion pad P having the enclosed space S (FIGS. 2 and 8). In the case of core pad 1 having recess 13 at bottom 1211 of recess hole 12 and cover member 2 having pillar 21 protruding toward recess hole 12 as shown in Fig. 3, when cover member 2 is used to cover hole opening 120, tip portion 211 of pillar 21 is inserted into recess 13 and tip portion 211 is fitted and locked into recess 13. In this way, pillar 21 supports hole bottom 1211 of core pad 1, contributing to the load-bearing performance of core pad 1. In addition, it is possible to simply form an interference portion 5 between the tip portion 211 of the column portion 21 and the recess 13, and press the tip portion 211 into the recess 13 to integrate the lid member 2 with the surface pad 6 with the core pad 1, but by further fixing the lid member 2 to the core pad 1 with a screw V or the like as shown in Figure 8, the desired cushion pad P in which the lid member 2 is integrally reinforced with the core pad 1 can be obtained.

[0022] According to the cushion pad and its manufacturing method configured in this way, the lower surface 1d of the core pad is provided with a recessed hole 12 having a hole opening 120, and the hole opening 120 is closed by the cover member 2 to form an enclosed space S, so that the cushion pad P has the same outer shape, but the enclosed space S becomes a void, and the weight is reduced. When the cover member 2 closes the hole opening 120 of the recessed hole 12, even if the recessed hole 12 is made large, the necessary strength and rigidity can be easily secured by assembling the cover member 2 to the core pad 1. Since the recessed hole 12 can be formed large, the weight can be significantly reduced compared to that of Patent Document 1. In addition, since the recessed hole 12 is formed large, the material cost of the core pad 1 can also be reduced. Then, when the pillars 21 and / or walls protrude from the lid inner surface 2a of the lid member 2 and the tip portions 211 of the pillars 21 and / or walls are fitted and locked into the recesses 13 provided in the hole bottom 1211 of the recessed hole 12, the pillars 21 and / or walls are fixed upright in the enclosed space S, and the load-bearing capacity of the portion corresponding to the seating surface portion 61 of the core pad 1 can be enhanced. In addition, since the tip portions 211 of the pillars 21 and / or walls are fitted and locked into the recesses 13 provided in the hole bottom 1211 of the recessed hole 12, the pillars (and / or walls) 21 are stable against load and are prevented from breaking or being damaged.

[0023] In addition, when the engaging portion 4 is formed on the outer lid surface 2d of the lid member 2, the core pad 1 is used as an insert product to produce the surface pad 6 with the core pad 1 by foam molding the surface pad 6, and then the lid member 2 can be attached, so that the polyurethane raw material g does not adhere to the engaging portion 4 when the surface pad 6 is molded. In the conventional product in which the locking portion 4 is provided on the underside of the bead foam molding member of Patent Document 1 corresponding to the core pad 1, even if the bead foam molding member is set in the upper mold 8, there is a risk that the polyurethane raw material g will penetrate between the bead foam molding member and the upper mold 8 during the foam molding of the surface pad 6. For this reason, it was necessary to take measures as described in JP 2018-175107, etc., but the present invention does not require such measures. The work of removing the hardened part of the polyurethane raw material g adhering to the locking portion 4 is eliminated.

[0024] Furthermore, conventional products had troublesome problems other than the locking part 4. When the underside of the foam bead molded part is set against the upper mold 8 and the polyurethane raw material g penetrates and hardens on the underside of the foam bead molded part during molding of the surface pad 6, when the cushion pad is installed on a vehicle and used, a contact rubbing noise, i.e., an abnormal noise, occurs at the hardened part. For this reason, conventionally, the hardened part that penetrated to the backside of the cushion pad had to be removed in a post-processing step. In contrast, in the present invention, the core pad 1 of the lower surface 1d of the core pad, which occupies the majority of the lower surface of the cushion pad, does not exist when the surface pad 6 is molded. Therefore, it is not necessary to remove the hardened portion of the polyurethane raw material g. Incidentally, even if the polyurethane raw material g penetrates and hardens into the hole wall 121 of the recessed hole 12 during molding of the surface pad 6, and the hardened portion remains in the cushion pad P, the hole wall 121 is not in contact with the vehicle, so no abnormal noise is generated and there is no problem. In addition, the hardened portion of the hole wall 121 is covered by the cover member 2 and cannot be seen, so there is no problem in appearance.

[0025] Furthermore, the vehicle body side on which the cushion pad P is installed has an uneven surface according to vehicle specifications, and the underside of the cushion pad must also be adjusted to fit the uneven surface. If the uneven surface is large, the polyurethane raw material g is likely to penetrate and harden on the underside of the foamed bead molding member even when the foamed bead molding member is set in the upper mold 8 during molding of the surface pad 6, resulting in a problem of hardened areas being formed. However, in the present invention, the cover member 2 is attached after molding of the surface pad 6 with the core pad 1 is completed, so this problem can be avoided.

[0026] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention according to the purpose and use. The shape, size, number, material, etc. of the core pad 1, the cover member 2, the locking portion 4, the surface pad 6, the foam molding mold 7, the cushion pad P, etc. can be appropriately selected according to the use. For example, a plurality of pillar portions 21 and wall portions can be provided, and a convex portion can be formed on the upper mold 8 in which the core member is set, so that the recessed hole 12 is filled. [Explanation of symbols]

[0027] 1 core pad 1d bottom surface 12 Hole 120 Anaguchi 13 Recess 2 Cover member 2a Lid inner surface (lid member inner surface) 2b Lid outer surface (lid member outer surface) 21 Pillar section 22 Accommodating groove portion (locking portion) 4 Clip (retaining part) 6 Surface Pad 8. First type (upper type) 9 Other molds (lower mold) T Cushion Pad Cover K Locked member

Claims

1. a core pad having a hole on the lower surface of the block-shaped bead foam molding and a recessed hole recessed toward the upper surface of the bead foam molding; a cover member that closes the hole opening so that an enclosed space is formed together with the hole wall of the recessed hole and is attached and fixed to the core pad; a surface pad of a soft polyurethane foam molded body that forms a seating surface portion and is laminated to cover the upper surface and side surfaces of the core pad; A cushion pad in which pillars and / or walls protrude from the inner surface of the lid member which forms the enclosed space, and the tip portions of the pillars and / or walls are fitted into and engaged with recesses provided in the bottom of the recess.

2. a core pad having a hole on the lower surface of the block-shaped bead foam molding and a recessed hole recessed toward the upper surface of the bead foam molding; a cover member that closes the hole opening so that an enclosed space is formed together with the hole wall of the recessed hole and is attached and fixed to the core pad; A cushion pad comprising: a surface pad of a soft polyurethane foam molded body that forms a seating surface portion and is laminated to cover the upper surface and side surfaces of the core pad; The cushion pad has a plurality of locking portions formed on an outer surface of the lid member for locking a member to be locked attached to the cushion pad cover.

3. A method for manufacturing the cushion pad of claim 1, The core pad is set in one mold so as to close the hole opening of the core pad; Next, the first mold and the second mold are closed to form a cavity, and a polyurethane raw material is foamed and cured in the cavity to form the surface pad. Then, the hole opening is covered with the lid member, The core pad has a recess at the bottom of the recessed hole, The cover member has a pillar portion and / or a wall portion protruding toward the recessed hole, A method for manufacturing a cushion pad, comprising inserting a tip portion of the pillar portion or wall portion into the recess when covering the hole opening with the lid member.

4. A core pad with a lid member laminated on the underside of a surface pad that forms a seating surface portion of a cushion pad, a core pad having a hole on the lower surface of the block-shaped bead foam molding and a recessed hole recessed toward the upper surface of the bead foam molding; a cover member that is attached and fixed to the core pad and covers the hole opening so that an enclosed space is formed together with the hole wall of the recessed hole, A core pad with a lid member in which pillars and / or walls protrude from the inner surface of the lid member that forms the enclosed space, and the tip portions of the pillars and / or walls are fitted and engaged into recesses provided at the bottom of the recess.

5. A core pad with a lid member laminated on the underside of a surface pad that forms a seating surface portion of a cushion pad, a core pad having a hole on the lower surface of the block-shaped bead foam molding and a recessed hole recessed toward the upper surface of the bead foam molding; a cover member that is attached and fixed to the core pad and covers the hole opening so that an enclosed space is formed together with the hole wall of the recessed hole, A core pad with a lid member, in which a plurality of locking portions for locking a member to be locked attached to a cushion pad cover are formed on an outer surface of the lid member.

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