Hot air ventilation oven device

Abstract

Provided is a hot air ventilation oven device that can stably heat a heated laminate formed by laminating a ventilation layer and a non-ventilation layer, and can reduce the time and cost required for manufacturing a soundproof body made of the heated laminate. 【Solution means】A hot air ventilation oven device includes a hot air heating body 2 in which a plurality of air outlets 22a for ejecting hot air and a plurality of air inlets 23a for discharging hot air are arranged adjacent to each other on a support surface portion 21 with which the ventilation layer of the outermost layer of the heated laminate is in contact. According to this configuration, the hot air ejected from the air outlet 22a enters the ventilation layer, hits the non-ventilation layer, and is discharged from the air inlet 23a. Thus, by ventilating the hot air in the thickness direction of the ventilation layer, the ventilation layer and the non-ventilation layer can be stably heated. Since the ventilation layer and the non-ventilation layer can be heated in a laminated state in this way, the time and cost required for manufacturing can be reduced.

Description

Technical Field

[0001] The present invention relates to a hot air ventilation oven device that heats a heated laminate in which a ventilation layer and a non-ventilation layer are laminated, with hot air.

Background Art

[0002] Sound insulators (silencers) for enhancing the sound insulation of the interior are used in automobiles. As such a sound insulator, for example, a configuration in which a plurality of non-woven fabric layers made of non-woven fabric or breathable films (or breathable sheets) having breathability are laminated has been proposed. Patent Document 1 proposes a method for manufacturing a sound insulator in which such a non-woven fabric layer and a breathable film are laminated. In this manufacturing method, in a state where the non-woven fabric layer and the breathable film are overlapped, they are heated with hot air and pressed in the heated state to manufacture a sound insulator having a desired form. Here, since the sound insulator is composed of a breathable material such as a non-woven fabric layer and a breathable film, in the conventional manufacturing method, all layers can be heated by blowing hot air from one side surface and passing it through in the plate thickness direction. Further, Patent Document 1 discloses a method for manufacturing a sound insulator using a breathable core material and a non-breathable skin material, in which the core material and the skin material are separately heated and then overlapped and pressed (paragraphs 0002 to 0004 of Patent Document 1).

[0003] On the other hand, Patent Document 2 proposes the above-mentioned sound insulator formed by laminating a felt layer and a non-ventilation layer. This conventional configuration can exhibit excellent sound insulation due to the sound insulation performance of the non-ventilation layer and the sound absorption performance of the felt layer. Further, Patent Document 2 also proposes a sound insulator having a three-layer structure in which the felt layer, the non-ventilation layer, and the felt layer are laminated. Since such a conventional configuration has high sound insulation, it can be suitably used for dash silencers, floor silencers, partition silencers, etc. of automobiles.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the soundproof body of Patent Document 2 has a structure in which a breathable felt layer and an airtight layer are laminated, as a manufacturing method, as described above, a method of separately heating the felt layer and the airtight layer and then laminating and pressing them can be applied. This is because since the airtight layer cannot allow hot air to pass through, when heating with hot air in a state where the felt layer and the airtight layer are laminated, it is difficult to heat both the boundary and the inside sufficiently and stably up to the boundary by the hot air, and if pressing is performed in a state of insufficient heating, there is a risk of peeling at the boundary. For these reasons, in the process of manufacturing a soundproof body formed by laminating a felt layer and an airtight layer, since it is necessary to heat both separately, the manufacturing process becomes complicated, and the time and cost required for manufacturing tend to increase.

[0006] The present invention proposes a hot air ventilation oven device that can stably heat a heated laminate in which a ventilation layer and an airtight layer are laminated, and can reduce the time and cost required for manufacturing a soundproof body manufactured from the heated laminate.

Means for Solving the Problems

[0007] The present invention is a hot air ventilation oven device for heating a flat heated laminate in which a breathable ventilation layer and an airtight non-ventilation layer are laminated and at least one outermost layer on one side is constituted by the ventilation layer, by blowing and ventilating hot air onto the ventilation layer of the outermost layer, the hot air heating means having a support surface portion against which the outer surface of the ventilation layer of the outermost layer abuts, and a plurality of jet outlets for jetting the hot air toward the ventilation layer of the outermost layer and a plurality of discharge outlets for discharging the hot air that has passed through the ventilation layer are arranged adjacent to each other on the support surface portion.

[0008] In such a configuration, the outermost ventilation layer is brought into contact with the support surface portion, and the heated laminate is disposed. By ejecting hot air from the ejection port of the support surface portion, the outermost ventilation layer and the non-ventilation layer overlapping the ventilation layer can be heated. Specifically, the hot air ejected from the ejection port enters and travels through the outermost ventilation layer, hits the non-ventilation layer and bounces back, and is discharged from the discharge port adjacent to the ejection port. In this way, by allowing the hot air to ventilate in the thickness direction of the outermost ventilation layer, the ventilation layer can be directly heated, and by allowing the hot air to hit the non-ventilation layer, the non-ventilation layer can be directly heated. Here, in the configuration of the present invention, since the ejection port and the discharge port are arranged adjacent to each other, a stable flow of hot air that ventilates in the thickness direction inside the ventilation layer from the ejection of the ejection port and is discharged to the discharge port can be generated, and the ventilation layer and the non-ventilation layer can be heated stably and easily. In addition, by bringing the outermost ventilation layer into contact with the support surface portion, the hot air ejected from the ejection port can be surely and stably introduced into the ventilation layer, and the effect of heating the ventilation layer and the non-ventilation layer is further improved.

[0009] Thus, according to the configuration of the present invention, in the state where the ventilation layer and the non-ventilation layer are laminated (heated laminate), since it can be stably heated to a desired temperature, by the press working after the heating, a molded product (corresponding to the above-described soundproof body) in which the ventilation layer and the non-ventilation layer are stably adhered can be molded. And in the molded product thus molded, the occurrence of a problem of peeling at the boundary between the ventilation layer and the non-ventilation layer is suppressed. Furthermore, according to this configuration, since the ventilation layer and the non-ventilation layer can be heated together, the manufacturing time and cost can be significantly reduced as compared with the conventional method of heating separately.

[0010] In the hot air ventilation oven device of the present invention described above, a configuration is proposed in which the ejection port and the discharge port each have a long slit shape, and on the support surface portion, the ejection port and the discharge port are alternately arranged side by side in a direction perpendicular to the longitudinal direction. Here, the longitudinal direction indicates the longitudinal direction of the ejection port and the discharge port.

[0011] In such a configuration, since a plurality of hot air flows that ventilate in the thickness direction of the ventilation layer from the air outlet to the air outlet are generated in the direction orthogonal to the longitudinal direction of the slit shape, the ventilation layer and the non-ventilation layer can be heated substantially evenly in the surface direction of the laminated body to be heated.

[0012] In the hot air ventilation oven apparatus of the present invention described above, a configuration is proposed in which the hot air heating means includes a gas ejection passage communicated with each air outlet and a gas discharge passage communicated with each air outlet.

[0013] In such a configuration, the hot air ejected from each air outlet can be stably supplied, the hot air that has passed through the ventilation layer can be stably discharged from each air outlet, and the flow of the hot air passing through the ventilation layer can be made more stable.

[0014] In the hot air ventilation oven apparatus of the present invention described above, a configuration is proposed in which two of the hot air heating means are provided, and the two hot air heating means are arranged such that their support surfaces face each other. Here, the two hot air heating means may be arranged such that their support surfaces always face each other, or may be arranged such that their support surfaces face each other only when heating the laminated body to be heated.

[0015] In such a configuration, for example, it can be applied to heating a laminated body to be heated in which the non-ventilation layer is sandwiched between ventilation layers, and both the ventilation layer and the non-ventilation layer can be stably heated.

Effect of the Invention

[0016] According to the hot air ventilation oven apparatus of the present invention, the ventilation layer and the non-ventilation layer of the laminated body to be heated can be stably heated to a desired temperature, and the manufacturing time and manufacturing cost can be significantly reduced as compared with the conventional method of heating the ventilation layer and the non-ventilation layer separately.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0018] Embodiments embodying the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1, the hot air ventilation oven device 1 of this embodiment includes upper and lower hot air heating bodies 2, 2, and heats the object to be heated laminate 51 disposed between the hot air heating bodies 2, 2. Here, after the object to be heated laminate 51 is heated to a predetermined temperature by the hot air ventilation oven device 1, it is formed into a desired shape by press working, and thus is applied to a soundproof body (such as a dash silencer) disposed in the interior of an automobile.

[0019] As shown in FIG. 6, the heated laminate 51 of this embodiment is composed of two felt layers 52 and 54 made of sheet-shaped felt and a sheet layer 53 made of a rubber-based sheet. The felt layers 52 and 54 are arranged so as to sandwich the sheet layer 53 in the thickness direction. Here, in this embodiment, the felt layers 52 and 54 arranged on both sides of the sheet layer 53 have different basis weights from each other. These felt layers 52 and 54 have air permeability, while the sheet layer 53 is airtight. The soundproof body formed from such a heated laminate 51 has excellent soundproof performance due to the sound absorption performance of the front and back felt layers 52 and 54 and the sound insulation performance of the sheet layer 53. In this embodiment, the thickness of the felt layers 52 and 54 is 10 to 20 mm, the thickness of the sheet layer 53 is 2 to 5 mm, and the thickness of the heated laminate 51 is about 40 mm.

[0020] The hot air ventilation oven device 1 heats the heated laminate 51 with hot air ejected from a hot air heating body 2, and includes a heating furnace 4 that heats the hot air and a blower 3 that supplies the hot air to the hot air heating body 2. And a supply pipe 6 that supplies the hot air heated in the heating furnace 4 to the hot air heating body 2 and a discharge pipe 5 that discharges the hot air used in the hot air heating body 2 are provided, and the supply pipe 6 and the discharge pipe 5 communicate with each other via the heating furnace 4 and the blower 3. Thus, the hot air ventilation oven device 1 of this embodiment includes a hot air circulation means constituted by a blower 3, a heating furnace 4, a discharge pipe 5, and a supply pipe 6, and circulates the hot air supplied to the hot air heating body 2 by the hot air circulation means. Further, the hot air circulation means includes a replenishing means (not shown) for replenishing the loss of hot air due to use in the hot air heating body 2, so that hot air can be stably supplied to the hot air heating body 2 at a desired flow rate. The hot air ventilation oven device 1 also includes a control means for driving and controlling the heating furnace 4 and the blower 3. By the control means controlling the heating furnace 4, the temperature of the hot air supplied to the hot air heating body 2 can be adjusted, and by controlling the blower 3, the flow rate (flow velocity) of the hot air supplied to the hot air heating body 2 can be adjusted.

[0021] In the hot air ventilation oven device 1 of this embodiment, the hot air circulation means are respectively connected to the upper and lower hot air heating bodies 2. Further, at least one of the upper and lower hot air heating bodies 2, 2 is movable in the horizontal direction, and the upper hot air heating body 2 is movable in the vertical direction. By controlling this horizontal movement, the upper and lower hot air heating bodies 2, 2 can be position-converted between positions facing each other and positions shifted in the horizontal direction. And by controlling the vertical movement of the upper hot air heating body 2, the hot air heating body 2 can be position-converted between a position in contact with the heated laminate 51 placed on the lower hot air heating body 2 and a position spaced upward from the heated laminate 51. The hot air ventilation oven device 1 is provided with control means for position-converting such a hot air heating body 2.

[0022] Next, the hot air heating body 2 according to the main part of the present invention will be described. As shown in FIG. 2, the hot air heating body 2 includes a rectangular plate-shaped table portion 11 (see FIG. 5) and a housing portion 12 on which the table portion 11 is disposed. The table portion 11 is disposed in the housing portion 12 such that the rectangular support surface portion 21 is exposed to the outside. In the table portion 11, a long slit-shaped ejection hole 22 formed along one side edge of the support surface portion 21 and a long slit-shaped discharge hole 23 formed in parallel with the ejection hole 22 are alternately arranged at a predetermined interval in a direction orthogonal to the one side edge. A plurality of such adjacent ejection holes 22 and discharge holes 23 are provided respectively. Here, the orthogonal direction is the same as the direction orthogonal to the longitudinal direction of the ejection hole 22 (and the discharge hole 23).

[0023] As shown in Fig. 3, the ejection holes 22 penetrate through the table portion 11 in the thickness direction, with ejection openings 22a opening in the support surface portion 21 of the table portion 11 and inflow openings 22b opening in the lower surface of the table portion 11 (the surface opposite to the support surface portion 21). On the other hand, as shown in Figs. 4 and 5, the discharge holes 23 are formed in the table portion 11 at a predetermined depth, with discharge openings 23a opening in the support surface portion 21 and outflow openings 23b opening in the side surface at one end in the longitudinal direction of the discharge holes 23. Thus, the discharge holes 23 do not open on the lower surface of the table portion 11 (do not penetrate in the thickness direction), and the discharge openings 23a in the support surface portion 21 communicate with the outflow openings 23b on one side surface. Incidentally, in this embodiment, the ejection openings 22a and the discharge openings 23a are formed to have the same length.

[0024] As shown in Figs. 3 and 4, in the housing portion 12, in the state where the table portion 11 is disposed, there are provided inside a sealed supply airspace 15 where the lower surface of the table portion 11 (the surface where the inflow openings 22b open) is exposed, and a sealed discharge airspace 16 where one side surface of the table portion 11 (the surface where the outflow openings 23b open) is exposed. And the supply airspace 15 communicates with the supply pipe 6 connected to one side surface of the housing portion 12, and communicates with the outside only via the supply pipe 6 and the ejection holes 22 of the table portion 11. Also, the discharge airspace 16 communicates with the discharge pipe 5 connected to the other side surface of the housing portion 12, and communicates with the outside only via the discharge pipe 5 and the discharge holes 23 of the table portion 11.

[0025] In such a hot air heating body 2, the hot air supplied from the supply pipe 6 to the supply airspace 15 enters into the respective ejection holes 22 from the respective inflow openings 22b of the table portion 11 and is ejected from the ejection openings 22a of the respective ejection holes 22. Then, the hot air flowing into the respective discharge holes 23 from the respective discharge openings 23a of the table portion 11 enters into the discharge airspace 16 from the respective outflow openings 23b and is discharged from the discharge pipe 5 via the discharge airspace 16.

[0026] Next, a mode of heating the object to be heated laminate 51 by the hot air ventilation oven device 1 of this embodiment will be described. With the upper and lower hot air heating bodies 2, 2 separated from each other, the laminate 51 to be heated is placed on the support surface portion 21 of the lower hot air heating body 2. At this time, in a state where the felt layers 52, 54 and the sheet layer 53 are laminated in advance (the state of the laminate 51 to be heated), it may be placed on the support surface portion 21, or the felt layers 52, 54 and the sheet layer 53 may be sequentially placed on the support surface portion 21 in the lamination order.

[0027] After thus placing the laminate 51 to be heated on the lower support surface portion 21, the upper hot air heating body 2 is moved downward, and the support surface portion 21 of the upper hot air heating body 2 is position-converted and held at a position in contact with the upper surface of the laminate 51 to be heated. In this state, the support surface portion 21 of the upper hot air heating body 2 contacts the upper surface (the upper felt layer 52) of the laminate 51 to be heated, and the support surface portion 21 of the lower hot air heating body 2 contacts the lower surface (the lower felt layer 54) of the laminate 51 to be heated.

[0028] In this state, by driving the hot air circulation means respectively connected to the upper and lower hot air heating bodies 2, 2, the hot air heated to a predetermined temperature in the heating furnaces 4, 4 is supplied to each hot air heating body 2, 2 through the supply pipes 6, 6. In each hot air heating body 2, as shown in FIG. 7, the hot air flowing into the supply airspace 15 from the supply pipe 6 is ejected from each ejection port 22a through each ejection hole 22 of the table portion 11. The hot air ejected from the ejection port 22a enters and travels through the felt layers 52, 54 that contact the support surface portion 21. Here, since the object to be heated laminate 51 is in contact with the support surface portion 21, the hot air ejected from the ejection port 22a easily enters the felt layers 52, 54. And since the ejection holes 22 are formed to penetrate in the thickness direction of the table portion 11, the hot air that has passed through the ejection holes 22 is ejected from the ejection port 22a along the thickness direction. For these reasons, the hot air ejected from the ejection port 22a enters and travels in the thickness direction of the felt layers 52, 54, and when it reaches the sheet layer 53, it hits the sheet layer 53 and bounces back, traveling in the reverse direction. The hot air traveling in the reverse direction passes through the felt layers 52, 54 and flows into the discharge port 23a of the support surface portion 21. Here, since the suction force by the blower 3 acts on the discharge port 23a through the discharge hole 23 and the discharge airspace 16, the hot air that has passed through the felt layers 52, 54 in the thickness direction as described above flows into the discharge port 23a and is discharged from the discharge hole 23 through the discharge airspace 16 to the discharge pipe 5. Then, the hot air discharged to the discharge pipe 5 is supplied again to the hot air heating body 2 by the blower 3 through the heating furnace 4.

[0029] By thus ventilating the hot air in the thickness direction within the felt layers 52, 54 of the object to be heated laminate 51, the felt layers 52, 54 can be heated, and by the hot air hitting the sheet layer 53, the sheet layer 53 can be heated. By generating the flow of this hot air respectively within the felt layers 52, 54 on both the upper and lower sides, the entire object to be heated laminate 51 can be sufficiently heated to the inside. Here, by driving and controlling the blower 3, the flow rate of the hot air supplied to the hot air heating body 2 is controlled so that the hot air ejected from each ejection port 22a travels through the felt layers 52 and 54 and hits the sheet layer 53 and bounces back. Then, due to the suction force generated through the discharge pipe 5 by driving the blower 3, the hot air bounced back by the sheet layer 53 can be discharged from each discharge port 23a. In this way, by driving and controlling the blower 3, the hot air can be stably circulated between the hot air heating body 2 and the hot air circulation means. Furthermore, by controlling the heating furnace 4, hot air at a predetermined temperature can be stably supplied to the hot air heating body 2. Thereby, the heated laminate 51 can be stably and reliably heated to a desired temperature by the hot air heating body 2. For example, in this embodiment, in order to heat the heated laminate 51 with a thickness of about 40 mm to a desired temperature (130 to 180 degrees), it is heated to hot air at a predetermined temperature (180 to 240 degrees) by the heating furnace 4.

[0030] According to the hot air ventilation oven device 1 of this embodiment, as described above, since the felt layers 52 and 54 and the sheet layer 53 constituting the heated laminate 51 can be stably heated to a desired temperature, a desired soundproof body (not shown) can be stably formed by performing press working after the heating. The soundproof body thus formed is suppressed from peeling at the boundary between the felt layers 52 and 54 and the sheet layer 53. Thus, according to the configuration of this embodiment, since the felt layers 52 and 54 and the sheet layer 53 can be heated to a desired temperature in a laminated state, there is no need to heat each layer separately as in the conventional configuration described above, and the time and cost required for the manufacturing process of the soundproof body can be significantly reduced.

[0031] In the above-described embodiment, the hot air heating body 2 corresponds to the hot air heating means according to the present invention. The supply air space 15 of the housing portion 12 and the ejection holes 22 of the table portion 11 correspond to the ejection gas path according to the present invention, and the discharge air space 16 of the housing portion 12 and the discharge holes 23 of the table portion 11 correspond to the discharge gas path according to the present invention.

[0032] The present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit of the present invention. For example, the dimensional shapes in the above-described embodiments can be appropriately changed.

[0033] In the above-described embodiments, the upper and lower table portions are arranged such that the respective jet outlets and discharge ports face each other (see FIG. 7), but the present invention is not limited to this, and the upper and lower table portions may be arranged such that they are shifted in a direction orthogonal to the longitudinal direction of the jet outlet. For example, as a configuration of another example shown in FIG. 8, the upper and lower table portions 11, 11 are arranged such that their respective jet outlets 22a and discharge ports 23a are shifted in the orthogonal direction so as not to face each other (in other words, they are arranged with a half-pitch shift). According to this configuration of the other example, since the flow of hot air from the jet outlet 22a to the discharge port 23a can be shifted in the orthogonal direction by the upper and lower felt layers 52, 54, the heated laminate 51 can be heated more uniformly in the planar direction. In addition, since this configuration of the other example is the same as the above-described embodiments except for changing the arrangement of the upper and lower table portions 11, 11, a detailed description thereof is omitted.

[0034] In the above-described embodiments, the heated laminate has a configuration having a felt layer, but the present invention is not limited to this, and other ventilation layers can be applied instead of the felt layer. For example, a configuration in which a ventilation layer made of a non-woven fabric other than felt is laminated may be used. Similarly, instead of the sheet layer of the rubber-based sheet, a sheet layer made of a non-air-permeable sheet other than the rubber-based sheet, a film layer made of a non-air-permeable film, etc. can be applied as the non-air-permeable layer.

[0035] In the above-described embodiments, the heated laminate is configured such that two felt layers having different basis weights are arranged on both sides of the sheet layer, but the present invention is not limited to this, and a configuration in which felt layers having the same basis weight are arranged on both sides of the sheet layer may be used. Further, the heated laminate may be configured such that a felt layer is arranged only on one side of the sheet layer. When heating this heated laminate, for example, hot air is passed through the felt layer in the same manner as in the above-described embodiments, and hot air is directly or indirectly (such as interposing a thin plate) applied to the sheet layer. Thereby, the heated laminate can be heated.

[0036] In the above-described embodiment, a configuration is adopted in which upper and lower hot air heating bodies are provided. However, the present invention is not limited to this, and a configuration in which the hot air heating bodies are arranged left and right may also be adopted. Even in this configuration, by sandwiching the object to be heated laminate between the support surfaces of the left and right hot air heating bodies, the object to be heated laminate can be heated in the same manner as in the above-described embodiment, and the same operational effects can be achieved.

[0037] In the above-described embodiment, a configuration is adopted in which two upper and lower hot air heating bodies are provided to heat an object to be heated laminate in which a sheet layer is sandwiched between felt layers. However, the present invention is not limited to this, and a configuration in which a hot air heating body is provided on either the upper or lower side may also be possible. This configuration can be applied to heat an object to be heated laminate in which a felt layer is disposed only on one side of the sheet layer. That is, by blowing hot air in a state where the felt layer of the object to be heated laminate is brought into contact with the support surface of the hot air heating body, the felt layer and the sheet layer can be heated in the same manner as in the above-described embodiment.

Explanation of Reference Numerals

[0038] 1 Hot air ventilation oven device 2 Hot air heating body (hot air heating means) 15 Supply airspace (jet gas path) 16 Exhaust airspace (exhaust gas path) 21 Support surface 22 Jet hole (jet gas path) 22a Jet outlet 23 Exhaust hole (exhaust gas path) 23a Exhaust outlet 51 Object to be heated laminate 52, 54 Felt layer (ventilation layer) 53 Sheet layer (non-ventilation layer)

Claims

A hot air ventilation oven device for heating a flat laminated body to be heated, which is capable of forming a molded product in which a ventilation layer having sound absorption and air permeability and an airtight layer having sound insulation and airtightness are laminated, and at least one outermost layer on at least one side is constituted by the ventilation layer, by blowing hot air onto the ventilation layer of the outermost layer to ventilate and heat it, comprising: a hot air heating body having a support surface portion that abuts against the outer surface of the ventilation layer of the outermost layer; on the support surface portion, a plurality of jet outlets for jetting the hot air toward the ventilation layer of the outermost layer and a plurality of discharge outlets for discharging the hot air that has passed through the ventilation layer are arranged adjacent to each other; a hot air ventilation oven device, characterized in that, in a state where the support surface portion of the hot air heating body abuts against the outer surface of the ventilation layer of the outermost layer, the hot air jetted from the jet outlet of the support surface portion into the ventilation layer bounces back in the airtight layer and is discharged from the discharge outlet adjacent to the jet outlet. According to claim 2, the laminated body to be heated is one in which the ventilation layers are laminated on both sides of the airtight layer, a support surface portion that abuts against the outer surface of the ventilation layer on one side of the airtight layer, and a hot air heating body on one side arranged on one side of the laminated body to be heated; a support surface portion that abuts against the outer surface of the ventilation layer on the other side of the airtight layer, and a hot air heating body on the other side arranged on the other side of the laminated body to be heated are provided; The hot air ventilation oven device according to claim 1, characterized in that, in a state where the support surface portions of the hot air heating bodies abut against the outer surfaces of the ventilation layers on both sides respectively, the hot air jetted from the jet outlet of the support surface portion on one side into the ventilation layer on one side bounces back in the airtight layer and is discharged from the discharge outlet adjacent to the jet outlet of the support surface portion, and the hot air jetted from the jet outlet of the support surface portion on the other side into the ventilation layer on the other side bounces back in the airtight layer and is discharged from the discharge outlet adjacent to the jet outlet of the support surface portion.

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