Duct for seat pad

Abstract

To provide a lightweight ducted seat pad and a method for manufacturing the same. [Solution] A ducted seat pad (1) is provided with an air distribution duct (3) having an air inlet (31) and an air outlet (32) in the duct path, and a pad main body (2) which is integrally foam-molded with the duct (3) as an insert, with a recess (21) formed on the surface (2a) on the occupant contact side to become an air outlet (210) which communicates with the air outlet (32). The inner layer of the duct (3) is made of a resin foam with a closed-cell structure, and the duct (3) is formed by joining together a pair of gutter-shaped half members (4, 5) which make up the duct (3).

Description

Technical Field

[0001] The present invention relates to a seat pad that constitutes a vehicle seat, and more particularly to a seat pad with a duct embedded therein and a method for manufacturing the same.

Background Art

[0002] There are seat pads that make up the seat part and backrest of a seat installed in a vehicle such as an automobile. Since the seat pad is the place where the seated occupant comes into contact through the skin, it gets sweaty in summer and feels cold in winter. Therefore, various seat pads with an air distribution duct for sending air conditioning air embedded and integrated have been proposed (for example, Patent Document 1). Patent Document 1 is a seat pad in which a pipe-shaped duct such as blow molding is embedded, and it is difficult to deform even when an occupant sits, and the required air distribution volume of the air conditioning air is ensured and it is satisfactory.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] However, the invention of Patent Document 1 is a seat pad in which a duct made of polypropylene resin or the like is inserted and the pad body of urethane foam is integrally foam-molded. Therefore, the bonding force between the duct and the pad body is weak. Therefore, in order to prevent the duct from coming off, it is necessary to cover the duct and attach a backing material such as a non-woven fabric to the back surface of the pad body. In addition, the duct is made of solid resin and is relatively heavy. In recent years, there has been a movement to meet the further weight reduction due to improvements in fuel efficiency and the like, and there is also an expectation for weight reduction in the duct.

[0005] The present invention aims to solve the above problems and provides a seat pad with a duct that promotes weight reduction and a method for manufacturing the same.

Means for Solving the Problem

[0006] In order to achieve the above object, the gist of the invention according to claim 1 is a duct for air distribution provided with an air inlet and an air outlet provided in a duct path, a depression serving as an air outlet communicating with the air outlet formed on the surface on the side where the occupant contacts, and a pad body integrally foam-molded with the duct as an insert. In the seat pad with a duct, the inner layer of the duct is made of a resin foam with a closed-cell structure, and the duct is formed by joining and integrating a pair of gutter-shaped half members that make up the duct. The seat pad with a duct is characterized in that. The seat pad with a duct according to the invention of claim 2 is characterized in that, in claim 1, the cross-sectional shape of the duct portion disposed in the horizontal direction of the duct is made flat with the vertical width smaller than the horizontal width, and a recess leading into the flow path is formed at the central portion in the horizontal width direction. The seat pad with a duct according to the invention of claim 3 is characterized in that, in claim 1 or 2, a short cylindrical portion is provided at the periphery of the air outlet in the duct. The seat pad with a duct according to the invention of claim 4 is characterized in that, in claims 1 to 3, a pair of gutter-shaped half members are provided with flange portions on both side edges of the gutter-shaped member forming the flow path recess, and an air outlet hole is provided in one of the pair of gutter-shaped members to form one gutter-shaped half member, and an air inlet hole is provided in the other gutter-shaped member to form the other gutter-shaped half member. The seat pad with a duct according to the invention of claim 5 is characterized in that, in claim 3 or 4, the duct is provided with an outer layer integrated with the outer surface of the inner layer, and the duct wall has a laminated structure in which the outer layer is made of a porous body made of a foam with an open-cell structure or a non-woven fabric.The gist of the invention according to claim 6 is that an air distribution duct provided with an air introduction part and having an air outlet provided in a duct path is set in a foam molding die, and then, through injection of a foam raw material and closing of the die, a pad body in which the duct is embedded and integrated is foam molded. In the foam molding, a method for manufacturing a duct-integrated seat pad in which a depression formed on the surface of the pad body on the occupant contact side is made into an air outlet in alignment with the air outlet, wherein the inner layer of the duct is a foam made of a thermoplastic resin having a closed-cell structure, and the duct is formed by joining and integrating a pair of gutter-shaped half members for making the duct, and the duct is set in a foam molding die, and then, through injection of a foam raw material and closing of the die, the pad body having the duct embedded on the back side is foam molded. The method for manufacturing a duct-integrated seat pad according to claim 7 is characterized in that, in claim 6, at a part of the duct part arranged in the horizontal direction of the duct, the cross-sectional shape is made into a flat shape in which the vertical width is smaller than the horizontal width, and a recess leading into the flow path is formed at the central part in the horizontal width direction. The method for manufacturing a duct-integrated seat pad according to claim 8 is characterized in that, in claim 6 or 7, a short cylindrical part is provided at the periphery of the air outlet of the duct. The method for manufacturing a duct-integrated seat pad according to claim 9 is characterized in that, in claims 6 to 8, a pair of gutter-shaped half members are provided with flange parts at both side edges of a gutter-shaped member for forming a flow path, and an air outlet hole is provided in one of the pair of gutter-shaped members to form one gutter-shaped half member, and an air inlet hole is provided in the other gutter-shaped member to form the other gutter-shaped half member. The method for manufacturing a duct-integrated seat pad according to claim 10 is characterized in that, in claims 6 to 9, the duct is provided with an outer layer integrated with the outer surface of the inner layer, and the duct wall has a laminated structure in which the outer layer is a porous body made of a foam having an open-cell structure or a non-woven fabric.

Effect of the Invention

[0007] The duct-integrated seat pad and the method for manufacturing the same according to the present invention are significantly lighter than conventional solid resin ducts, can promote weight reduction, and exhibit excellent effects.

Brief Description of the Drawings

[0008]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, the duct-equipped seat pad and its manufacturing method according to the present invention will be described in detail. (1) Embodiment 1 FIGS. 1 to 12 show one form of the duct-equipped seat pad (hereinafter also simply referred to as "seat pad") and its manufacturing method according to the present invention. FIG. 1 is a plan view of the seat pad, FIG. 2 is a view taken along the line II-II in FIG. 1, FIG. 3 is a view taken along the line III-III in FIG. 1, FIG. 4 is a view taken along the line IV-IV in FIG. 1, FIG. 5 is a partially enlarged view of FIG. 4, FIG. 6 is an alternative view to FIG. 5, FIG. 7 (a) is a cross-sectional view of the gutter-shaped member, and (b) is a cross-sectional view of the half-cut member. FIG. 8 (a) is a cross-sectional view around the air outlet in FIG. 5, (b) is an alternative view, and (c) is a cross-sectional view of the duct with a short tube portion in (b) set in the lower mold. FIG. 9 is an explanatory cross-sectional view of the foaming mold in which the foaming raw material is being injected in the mold-open state, FIG. 10 is an explanatory cross-sectional view of the foaming mold with the mold closed and heading for foam molding, FIG. 11 is an explanatory cross-sectional view after the foam molding is completed, and FIG. 12 (a) is an enlarged view around the raised portion in FIG. 10, and (b) is an explanatory view showing that the foaming raw material is penetrating into the porous body from (a). In addition, each figure emphasizes and shows the main parts such as the duct 3 for easy understanding of the drawing, and omits the parts not directly related to the present invention. The recess is shown only in FIGS. 3 and 4.

[0010] 1) Duct-equipped seat pad The duct-equipped seat pad 1 is a back pad for a backrest or a cushion pad that supports the lower body of a seated occupant. In this embodiment, it is applied to a vehicle front cushion pad as shown in FIG. 1. If the cushion pad is covered with a skin to form a seat cushion, a seat for a vehicle can be formed by a backrest with a skin covering a known back pad and a known headrest. The duct-equipped seat pad 1 includes a pad body 2 and a duct 3.

[0011] The duct 3 is a ventilation duct provided with an air inlet 31 and an air outlet 32 in the duct path. This ventilation duct 3 is composed of a duct wall having a laminated structure in which the inner layer 3A is a foam made of a thermoplastic resin with a closed-cell structure, and the outer layer 3B is a porous body made of a non-woven fabric 3B2 (or a foam 3B1 with an open-cell structure) (Figs. 4 to 6). Here, the duct 3 has a ventilation flow path u that is substantially H-shaped in plan view as shown in Fig. 1, and a pair of pipe-shaped duct portions 3D extend in the vehicle longitudinal direction from both ends in the vehicle width direction of the flat hollow base portion 3K. A plurality of air outlets 32 are opened on the surface side of the duct 3. The "surface" side of the present invention refers to the side of the surface that contacts when the occupant sits on the seat. The duct 3 is arranged horizontally on the back surface 1b side of the seat pad with the base portion 3K and each duct portion 3D (Figs. 2 and 3). The duct portion 3D does not have a circular cross-sectional shape, and at the portion where it is arranged horizontally, it has a flat hollow oval shape with a vertical width 3T smaller than the horizontal width 3Y (Fig. 4). In the seat pad 1 where the weight is reduced and the thickness h tends to decrease, the vertical width 3T of the duct portion is made as small as possible, and a large cushioning thickness width of the pad body 2 is ensured.

[0012] In each duct portion 3D of the duct 3, a recess 36 leading into the flow path u is appropriately formed at the central portion in the width direction. The recesses 36 having the cross-sectional shape shown in Fig. 4 are formed continuously or intermittently in the extending direction of the duct 3. This duct 3 has a duct wall with a laminated structure of the inner layer 3A of a closed-cell structure foam and the outer layer 3B of a non-woven fabric 3B2 as described above, and there is a risk that the duct 3 may be crushed by the seated occupant. Therefore, before being crushed, the contact portion 39 on the flow path side of the recess 36 is made to abut on the bottom, and in Fig. 4, the required air volume is ensured by the flow path u remaining on both the left and right sides of the recess 36. The base portion 3K is provided with recesses 36 leading into the base portion 3K on both the surface side and the back surface side at the central portion in the vehicle width direction to ensure the required flow path u (Fig. 3).

[0013] The duct 3 of this embodiment is formed by joining and integrating a pair of gutter-shaped half members 4 and 5 that make up the duct 3. After forming a pair of gutter-shaped members 41 and 51 that are split into two vertically as shown in Fig. 7(A), air inlet holes 42 and air outlet holes 52 are opened as shown in Fig. 7(B) to form a pair of half members 4 and 5, and then the two are joined and integrated to produce the duct 3 of Figs. 1 and 2 (details will be described later).

[0014] The resin that constitutes the foam of a thermoplastic resin with a closed-cell structure, which becomes the inner layer 3A of the duct 3, includes foamed polypropylene, foamed polyethylene, foamed polystyrene, etc. Although foamed polyurethane is not a foam of a thermoplastic resin, it is considered to be included in the foam of a thermoplastic resin as referred to in the present invention. The inner layer 3A can also be made of foamed polyurethane. The resin that constitutes the porous non-woven fabric 3B2, which becomes the outer layer 3B of the duct 3, includes polypropylene, polyethylene, polyester, nylon, PET, etc. The non-woven fabric 3B2 includes those in which the fibers are adhered to each other using an adhesive, those in which thermoplastic synthetic fibers are used and the fibers are fused to each other by heat treatment, etc. When the porous body is a foam 3B1 with an open-cell structure instead of the non-woven fabric 3B2, the resin that constitutes the foam includes foamed urethane, foamed polyethylene, etc. It is also possible to compress the foam with a closed-cell structure to form an open-cell structure. In addition to the foam that constitutes the inner layer 3A, if the porous body that constitutes the outer layer 3B is also made of a thermoplastic resin such as foamed polyethylene, it becomes easier to vacuum mold the gutter-shaped members 41 and 51, which is more preferable. If the foam that constitutes the inner layer 3A and the porous body that constitutes the outer layer 3B are made of the same thermoplastic resin, it becomes even easier to vacuum mold the gutter-shaped members 41 and 51, which is even more preferable.

[0015] The pad body 2 is a foam body formed by injecting a soft polyurethane foam raw material g or the like into a foam molding die 7 and foam-molding it, and constitutes the main part of the vehicle seat pad 1. A plurality of depressions 21 serving as air outlets 210 communicating with each air ejection port 32 are formed on the surface 2a on the side where the occupant contacts, and the duct 3 is an insert part and is integrally foam-molded. The air inlet 31 is exposed on the back surface 2b side of the pad body 2. Side portions 2B are provided on both sides of the main part 2A constituting the main part of the seat pad, and suspension grooves 27 are provided at both boundaries on the surface 1a side of the seat pad. Reference numeral 27a indicates a vertical groove, reference numeral 27b indicates a horizontal groove, and reference numeral 2C indicates a joint portion with the backrest.

[0016] A part of the pad body 2 extends beyond the duct outer surface 3a in contact with the duct 3 as shown in FIG. 5 and enters into the space between the fibers of the non-woven fabric 3B2 related to the porous body and hardens. In the case where the porous body is a foam body 3B1 having an open-cell structure, as shown in FIG. 6, it enters into the bubbles of the foam body and hardens. In the case of the non-woven fabric 3B2 or the foam body 3B1 having an open-cell structure with a gap on the duct outer surface 3a, during the foam molding process of the pad body 2, the foam raw material g easily penetrates there and hardens, and the pad body 2 and the duct 3 are integrated. In the surface layer region where the foam raw material g penetrates from the duct outer surface 3a of the outer layer 3B, a combined surface layer Z in which the hardened layer of the foam raw material g and the porous body are intertwined is formed, resulting in the desired seat pad 1 with a duct.

[0017] Furthermore, although the pad body 2 is integrally foam-molded with the duct 3 as an insert part, if the periphery around the air ejection port 32 provided in the duct 3 is an air ejection port 32 with a short cylindrical part 33 protruding as shown in FIGS. 8(b) and 8(c) of the present embodiment instead of FIG. 8(a), a more preferable seat pad 1 with a duct is obtained. This is because during the foam molding of the pad body 2, the intrusion of the foam raw material g from the air ejection port 32 into the duct 3 can be effectively blocked by the raised part 82 of the lower mold 8 (details will be described later).

[0018] 2) Method for manufacturing a seat pad with a duct The seat pad 1 with a duct is obtained by setting the duct 3 in the foam molding die 7, and then foam molding the pad body 2 that embeds and integrates the duct 3 through injection of the foam raw material g and closing of the die. A ventilation duct 3 provided with an air inlet 31 and an air outlet 32 in the duct path is set in the foam molding die 7, and in the foam molding of the pad body 2, a depression 21 formed on the surface 2a of the pad body on the occupant contact side is made into an air outlet 210 in alignment with the air outlet 32 to produce the seat pad 1 with a duct.

[0019] The foam molding die 7 includes an upper die 9 and a lower die 8 as shown in Fig. 9. When the die is closed as shown in Fig. 10 with a hinge (not shown) as a fulcrum, a cavity C of the seat pad 1 with a duct is formed by the lower die cavity surface 81 with a large degree of depression overall and the upper die cavity surface 91 that is substantially flat but has some depressions. Incidentally, the foam molding die 7 in Figs. 9 to 12 has a die structure for foam molding the pad body 2 integrated with the duct in a posture where it is upside down from the seat pad 1 in Fig. 2 in the vehicle installation state.

[0020] The duct 3 is composed of a duct wall having a laminated structure in which the inner layer 3A is a foam of a thermoplastic resin having a closed-cell structure and the outer layer 3B is a porous body made of a non-woven fabric 3B2 (or a foam 3B1 having an open-cell structure). Since the duct 3 of the present invention has no rigidity like solid resin, it is difficult to open the air outlet 32 after forming it into a pipe shape. Therefore, prior to the foam molding of the pad body 2, the duct 3 is manufactured, for example, as follows.

[0021] First, prepare a sheet-like material for a duct having a two-layer structure in which a porous body composed of a thermoplastic resin foam having an independent bubble structure and a nonwoven fabric 3B2 are integrated. The thermoplastic resin foam for the inner layer 3A and the nonwoven fabric 3B2 for the outer layer 3B are laminated and integrated via an adhesive layer. The adhesive layer is formed by heat fusion at the joint surface between the thermoplastic resin foam and the nonwoven fabric 3B2, or a low melting point film interposed at the joint surface or the like. Next, the sheet-like material is formed into the gutter-shaped members 41 and 51 shown in Fig. 7(A) in which the inner layer 3A is a thermoplastic resin foam and the outer layer 3B is a nonwoven fabric 3B2 by vacuum forming (or pressure air forming). Flange portions 4b and 5b as shown in the figure are provided on both side edges of the gutter-shaped members 41 and 51 for creating recesses 410 and 510 for forming a flow path. Subsequently, an air jet outlet hole 52 is provided in one gutter-shaped member 51 to form one half member 5, and an air inlet hole 42 is provided in the other gutter-shaped member 41 to form the other half member 4. Thereafter, the flange portions 4b and 5b of both half members 4 and 5 are joined and integrated to form the duct 3. Unlike a solid resin, this duct 3 is flexible, and it is extremely difficult to provide an air inlet 31 and an air jet outlet 32 in the state of a pipe-shaped duct. Therefore, air inlet holes 42 and air jet outlet holes 52 are provided in the gutter-shaped members 41 and 51 formed from the sheet member to form half members 4 and 5, and then both half members 4 and 5 are adhered. As shown in Fig. 7(B), the duct 3 is completed by adhering the flange portion 5b extending along both side edges of the gutter main body 5a having the air jet outlet hole 52 with the recess 510 facing downward to the flange portion 4b extending along both side edges of the gutter main body 4a having the air inlet hole 42 with the recess 410 facing upward. At the stage when the duct 3 is formed, the air jet outlet hole 52 becomes the air jet outlet 32, and the air inlet hole 42 becomes the air inlet 31. In the duct 3, at the portions of the base portion 3K and the duct portion 3D arranged in the horizontal direction, the cross-sectional shape is made flat with the vertical width 3T smaller than the horizontal width 3Y, and a recess 36 leading into the flow path u is appropriately formed at the central portion in the horizontal width direction (Figs. 4 and 9).

[0022] Using the duct 3 and the foam molding die 7, the sheet pad 1 with a duct is manufactured as follows, for example. First, the foam molding die 7 is set in the mold-open state shown in Fig. 9. In the lower die 8 in this mold-open state, the duct 3 is set with its back surface facing upward. The non-woven fabric 3B2 (or the foam 3B1 having a closed-cell structure) which is a porous body of the outer layer 3B is made of a thermoplastic resin, and the duct 3 formed by joining and integrating a pair of gutter-shaped half members 4 and 5 is set in the lower die 8. The air inlet 31 of the duct 3 is pre-treated to be blocked with a sealing tape. The non-woven fabric 3B2 (or the foam 3B1 having a closed-cell structure) of the outer layer 3B is more preferably made of the same thermoplastic resin as the foam made of a thermoplastic resin having an independent-cell structure of the inner layer 3A. The tip portion of the raised portion 82 of the lower die 8 is inserted into each air outlet 32 facing downward so as to block the air outlet 32, and the duct 3 is set in the lower die 8.

[0023] Next, with the mold still in the open state, a predetermined amount of a foaming raw material g such as a urethane foam stock solution for sheet pad molding is injected onto the cavity surface 81 of the lower die using an injection hose NL or the like. Subsequently, the upper die 9 is actuated to close the mold (Fig. 10). When the upper die 9 and the lower die 8 are closed, a cavity C for the sheet pad 1 with the duct 3 inserted is formed. By closing the mold, the elastic duct 3 is pressed by the upper die 9, and as a reaction, the tip portion of the frustum-shaped raised portion 82 closely adheres to the inner peripheral wall of the air outlet 32, sealing the air outlet 32.

[0024] Incidentally, when a short tube portion 33 as shown in Fig. 8(b) is provided at the periphery of the air outlet 32, it is preferable because the air outlet 32 can be sealed with higher accuracy by the raised portion 82 when the mold is closed. The inner diameter side of the short tube portion 33 becomes the inner layer 3A made of a foam having an independent-cell structure. Since the inner layer 3A having an independent-cell structure into which the raised portion 82 is inserted and abuts during mold closing can serve as an elastic gasket, the air outlet 32 can be sealed more reliably. The short tube portion 53 can be provided by shaping the tip portion of the punch T as shown in Fig. 8(a) or adjusting the heating temperature of the punch T or the like when opening the hole 52 for the air outlet. Note that the short tube portion 53 provided on the gutter-shaped member 51 becomes the short tube portion 33 when it becomes the duct 3.

[0025] After the mold is closed, the process proceeds to the foaming and molding in the main process. A pad body 2 made of a soft polyurethane foam molded body having a contact side portion of the seated occupant on the surface 2a side is foam molded. With the air ejection port 32 sealed by the raised portion 82, the pad body 2 with the duct 3 embedded on the back surface 2b side is foam molded. Here, at the initial stage of the foam molding after the mold is closed, the foaming of the foaming raw material g proceeds as shown in Fig. 12(a), and its upper surface rises. Subsequently, as shown in Fig. 12(b), the foaming raw material g reaches the outer surface 3a of the duct, but since the outer layer 3B of the duct 3 is a non-woven fabric 3B2, the foaming raw material g easily enters between the fibers. A part of the foaming raw material g penetrates beyond the duct outer surface 3a in contact with the duct 3 and into the space between the fibers constituting the non-woven fabric of the non-woven fabric 3B2 related to the porous body (or into the bubbles of the foam 3B1 having an open-cell structure), and hardens. A combined surface layer Z is formed in which the foaming raw material g impregnated on the duct outer surface 3a side of the outer layer 3B is intertwined and integrally hardened with the non-woven fabric 3B2.

[0026] When the foam molding of the pad body 2 is completed, a desired duct-integrated seat pad 1 in which the duct 3 and the pad body 2 are firmly bonded and integrated is produced by forming such a combined surface layer Z, without particularly relying on the backing material (Fig. 5). Even when the outer layer 3B is a foam 3B1 having an open-cell structure instead of the non-woven fabric 3B2, the foaming raw material g can penetrate and harden into the mutually communicating bubbles to form the combined surface layer Z (Fig. 6), and a desired duct-integrated seat pad 1 in which the duct 3 and the pad body 2 are bonded and integrated can be produced. Reference numeral 88 denotes a raised portion for forming a suspension groove, and reference numerals 89 and 99 denote mating surfaces. Other configurations are the same as those of the duct-integrated seat pad 1 described in 1), and the description thereof is omitted. The same reference numerals as those in 1) indicate the same or corresponding parts.

[0027] (2) Embodiment 2 In the duct-integrated seat pad and its manufacturing method of the present embodiment, as shown in FIGS. 13 to 16, the air inlet 31 is not provided on the back side of the duct 3, but on the side of the duct 3. A pipe hole exposed on one side of the horizontally arranged pipe-shaped duct 3 is utilized as the air inlet 31. The duct 3 is cross-shaped in plan view as shown in FIG. 13, and duct portions 3D extend from the base 3K of the intersection portion in the vehicle longitudinal direction and the vehicle width direction. The right side of FIG. 13 corresponds to the front of the vehicle, and the tip portion of the duct portion 3D at the front is closed. In the left vehicle rear duct portion 3D, the pipe-shaped flow path u is exposed as it is, and the opening at the left end becomes the air inlet 31.

[0028] Similar to Embodiment 1, the duct 3 is formed by molding a pair of gutter-shaped members 41 and 51 from a sheet-like material. Flange portions 4b and 5b are provided on both side edges of the gutter-shaped members 41 and 51 that create the recesses 410 and 510 for forming the flow path. Next, an air ejection port hole 52 is provided in the gutter-shaped member 51 arranged on the front side, and an opening gutter-shaped portion 59 having a gutter shape in side view is formed on one side (one end side) thereof to obtain a front-side half member 5. Here, since the recess 510 for forming the flow path of the gutter-shaped member 51 appears in a gutter shape on one side, the formation of the opening gutter-shaped portion 59 is not particularly required. Also, an opening gutter-shaped portion 49 is formed in the gutter-shaped member 41 arranged on the back side at the portion facing the opening gutter-shaped portion 59. However, since the recess 410 for forming the flow path of the gutter-shaped member 41 appears in a gutter shape on one side, the formation of the opening gutter-shaped portion 49 is not particularly required, and the gutter-shaped member 41 becomes the back-side half member 4. Thereafter, as shown in FIG. 14(A), the flange portions 4b and 5b of the two half members 4 and 5 are opposed to each other, and by joining and integrating the two half members 4 and 5, a duct 3 is formed with air inlets 31 formed by the two opening gutter-shaped portions 49 and 59 as shown in FIG. 14(B). The symbol L indicates the joining line of the two half members 4 and 5.

[0029] In the seat pad 1 with a duct, which includes a pad body 2 integrally foam-molded with the duct 3 as an insert, the inner layer 3A of the duct wall is a foam with a closed-cell structure, and the outer layer 3B of the duct wall is a laminated duct wall with a non-woven fabric 3B2 (or a foam 3B1 with an open-cell structure), and a part 25 of the pad body passes through the outer surface 3a of the duct and enters into the space between the fibers of the non-woven fabric 3B2 (or into the bubbles of the foam related to the porous body) and hardens, forming the seat pad 1 with a duct. FIG. 15 is a cross-sectional view corresponding to FIG. 3 and has the same cross-sectional view as FIG. 3. On the other hand, FIG. 16 is a cross-sectional view corresponding to FIG. 2, but the air inlet 31 is opened toward the rear of the vehicle on the back surface 1b side of the seat pad, and a space for the connection pipe from the air-conditioning unit is secured on the rear side of the vehicle of the air inlet 31. Further, FIG. 17 (a) shows a cross-sectional view of the duct portion 3D in FIG. 16, and a recess 36 similar to that in the first embodiment is formed in the duct portion 3D. When the occupant is seated, before the duct flow path u is crushed by the weight of the occupant indicated by the black arrow, the contact portion 39 of the recess 36 on the flow path side touches the bottom as shown in FIG. (b) of the same figure, and the required air volume is ensured by the flow path u remaining on both the left and right sides of the recess 36. The recess 36 is provided continuously or intermittently in the extending direction of the duct portion 3D, but FIGS. 13 to 16 are omitted from the illustration. The symbol M indicates the buttocks of the seated occupant. Other configurations are the same as those in the first embodiment, and the description thereof is omitted. The same reference numerals as those in the first embodiment indicate the same or corresponding parts.

[0030] (3) Effects In the seat pad with a duct and its manufacturing method configured as described above, since the duct wall of the duct 3 has the inner layer 3A as a foam made of a thermoplastic resin with a closed-cell structure, airtightness can be ensured, and it functions as the air distribution duct 3. And since the inner layer 3A is made of a foam and the outer layer 3B is a porous body made of a foam 3B1 with an open-cell structure or a non-woven fabric 3B2, it can be significantly lightened compared to the conventional solid blow-molded duct with rigidity and weight. With the spread of hybrid vehicles, electric vehicles, etc., weight reduction is expected for each part of the vehicle. The seat pad 1 adopting the duct 3 with such a configuration can fully meet such expectations. It becomes a seat pad with a duct that helps improve fuel efficiency.

[0031] On the other hand, if the duct 3 has an inner layer 3A made of a foam with a closed-cell structure and an outer layer 3B made of a porous body formed of a foam 3B1 with an open-cell structure or a non-woven fabric 3B2, there is a concern about a decrease in rigidity. However, since the outer layer 3B is a non-woven fabric 3B2 or a foam 3B1 with an open-cell structure, and during the foam molding of the pad body 2, a part of the foam raw material g penetrates into the mesh space of the non-woven fabric 3B2 or the bubbles of the open-cell foam from the outer surface 3a of the duct and hardens, forming a hard bonding surface layer Z on the side of the outer surface 3a of the duct of the outer layer 3B, even the duct 3 composed of a foam or a non-woven fabric 3B2 has increased rigidity and is not easily crushed by the seated occupant.

[0032] Furthermore, at the site where the duct 3 is disposed in the horizontal direction, the cross-sectional shape is made flat with the vertical width 3T smaller than the horizontal width 3Y, so that the thickness of the cushioning pad body 2 can be set as large as possible, and a recess 36 leading into the flow path u is formed at the central portion in the horizontal width direction of the duct 3 to ensure the required air volume of the duct 3. For example, when an occupant sits on the seat pad 1 in the state of Fig. 17(a), before the duct 3 is crushed due to deflection, the contact portion 39 on the flow path side of the recess 36 bottoms out as shown in Fig. 17(b), and the flow paths u formed on both sides of the recess 36 remain, ensuring the required air volume.

[0033] In addition, a blow-molded duct made of a conventional polypropylene resin or the like has a weak adhesive force with the urethane foam raw material g of the pad body 2, and even when manufacturing the seat pad 1 with the duct embedded, the duct is likely to fall off, so a backing material such as a non-woven fabric 3B2 is required (Patent Document 1). However, the present invention is excellent in the integration of the duct 3 and the pad body 2 and does not require a backing material. When the outer layer 3B of the duct 3 is a foam 3B1 with an open-cell structure or a non-woven fabric 3B2, during the foam molding process of the pad body 2, a part of the foam raw material g penetrates beyond the outer surface 3a of the duct and into the bubbles of the foam or between the fibers constituting the non-woven fabric of the non-woven fabric 3B2 and hardens. Then, a bonding surface layer Z that firmly bonds the duct 3 and the pad body 2 is formed on the side of the outer surface 3a of the outer layer 3B, so that strong bonding integration of the two can be achieved without a backing material. The number of parts of the backing material can also be reduced.

[0034] When the porous body of the duct 3 is made of a thermoplastic resin, both the inner layer 3A and the outer layer 3B of the duct 3 are made of a thermoplastic resin, so that the duct 3 can be easily molded. If the foam of the inner layer 3A and the porous body of the outer layer 3B of the duct wall are made of the same thermoplastic resin, the molding of the duct 3 becomes even easier.

[0035] Further, when the duct 3 is formed by joining and integrating a pair of gutter-shaped half members 4 and 5 for making the duct 3, even for a flexible duct 3, after forming the half member 5 with the air outlet hole 52, the duct 3 is formed by joining, so that the duct 3 can be easily manufactured. A pair of gutter-shaped members 41 and 51 are formed from a sheet-like material for the duct 3. Next, the air outlet hole 52 is provided in one gutter-shaped member 51 to form one half member 5, and the air inlet hole 42 is provided in the other gutter-shaped member 41 to form the other half member 4. Subsequently, when both half members 4 and 5 are joined and integrated to form the duct 3, the duct 3 can be manufactured extremely easily and surely. The air inlet hole 42 becomes the air inlet 31 of the duct 3, and the air outlet hole 52 becomes the air outlet 32 of the duct. Further, instead of providing the air outlet hole 52 in one gutter-shaped member 51 to form one half member 5, the air outlet hole 52 is provided in one gutter-shaped member 51 and an opening gutter-shaped portion 59 is formed on one side thereof to form one half member 5, and an opening gutter-shaped portion 49 is also formed in the other half member 4 at a position facing the opening gutter-shaped portion 59. When the air inlet 31 is provided by both opening gutter-shaped portions 49 and 59 by joining and integrating both half members 4 and 5, the air inlet 31 can be simply provided on one side of the duct 3. In addition, the arrangement correspondence of the air inlet 31 is widened, and the duct design has flexibility. Thus, the sheet pad with the duct and its manufacturing method exhibit the various excellent effects described above and are extremely beneficial.

[0036] In the present invention, it is not limited to that shown in the above embodiment, and various modifications can be made within the scope of the present invention according to the purpose and application. The shapes, sizes, numbers, materials, etc. of the pad body 2, the duct 3, the half members 4 and 5, the foam molding die 7, etc. can be appropriately selected according to the application. Although the embodiment is applied to a cushion pad, it can also be applied to a back pad for a backrest.

Explanation of Symbols

[0037] 1 Sheet pad 2 Pad body 2a Surface 21 Depression 210 Air outlet 3 Duct (air distribution duct) 3A Inner layer 3B Outer layer 3B1 Foam with continuous bubble structure 3B2 Non-woven fabric 3a Duct outer surface 31 Air inlet 32 Air outlet 36 Depression 4, 5 Split members 41, 51 Gutter-shaped members 42 Hole for air inlet 49, 59 Gutter-shaped part for opening 52 Hole for air outlet 7 Foam molding die g Foaming raw material

Claims

1. A duct for a seat pad provided with an air inlet and an air outlet provided in a duct path, comprising a duct wall having a laminated structure in which an inner layer is a resin foam with a closed-cell structure and an outer layer is a porous body made of a foam with an open-cell structure or a non-woven fabric.

2. The duct for a seat pad according to claim 1, wherein a convex portion directed toward the duct lower wall is provided on the upper wall of the duct inside the duct, and an air distribution passage is formed between the convex portion and the duct lower wall.

3. The duct for a seat pad according to claim 1 or 2, wherein a cylindrical portion made of a resin foam protruding outward in the direction of the outside of the duct is provided at the periphery of the air outlet.

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