JP2018130398A - Mold and seat pad production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a seat pad efficiently.SOLUTION: In a first mold 22, a concave part 28 capable of fitting a convex part 16 of a first layer part 12 is formed on a die surface. A protrusion 30 is provided so as to protrude in a holding wall surface 28a of the concave part 28 in the mold surface of the first mold 22. The protrusion 30 is made to interfere with the convex part 16 of first layer part 12 and the convex part 16 is fitted in the concave part 28, and thereby the first layer part 12 is mounted to the first mold 22. A raw material is foamed and cured in a cavity defined between the first mold 22 and a second mold being demolded, and a second layer part is molded so as to be joined with the first layer part 12 mounted to the first mold 22 and facing the cavity, and thereby a seat pad is obtained.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a mold for molding a sheet pad made of a multilayered foam and a method for manufacturing the seat pad.

  As a seat pad used as a core material for a vehicle seat or the like, a seat pad having an upper layer formed of polyurethane foam and a lower layer formed of polystyrene foam has been proposed (for example, Patent Document 1). reference). As in Patent Document 1, by configuring a part of the seat pad with a bead foam obtained by foamed bead molding such as a polystyrene foam, there is an advantage that the weight of the seat pad can be reduced.

  A seat pad as in Patent Document 1 is a cavity defined between an upper mold and a lower mold to which a polystyrene foam obtained by molding is separately attached. By foam molding a polyurethane foam, The layers are joined. At this time, the polystyrene foam is attached to the upper mold by fitting the polystyrene foam having an uneven outer shape to the upper mold surface that is uneven according to the outer shape of the polystyrene foam.

JP-A-9-70330

  Since the above-mentioned bead foam such as polystyrene foam is a foam, dimensional variations occur, and the dimensional accuracy varies depending on the season. For this reason, if it is the method of attaching a bead foam to an upper mold | type by fitting the unevenness | corrugation of an upper mold | type and a bead foam, the bead foam smaller than a predetermined dimension will drop | omit from an upper mold | type. And, in order to prevent the bead foam from falling off the upper mold, it takes time and effort to adjust.

  The present invention has been proposed to solve these problems in view of the above-mentioned problems related to the prior art, and provides a mold and a method of manufacturing a seat pad capable of efficiently obtaining a seat pad. With the goal.

In order to overcome the above-mentioned problems and achieve the intended object, the mold of the invention according to claim 1 of the present application is
Of the seat pad configured by laminating a first layer portion made of a bead foam and a second layer portion made of a foam different from the first layer portion, the second layer portion is the first layer portion. A mold that is molded so as to be joined to a layer part,
A first mold to which the first layer part can be attached by fitting the convex part on the outer surface of the first layer part and the concave part formed on the mold surface;
By closing the mold with the first mold, a second mold that defines a cavity matched to the second layer portion between the first mold and the first layer portion attached to the first mold. Prepared,
In summary, the first mold has a protrusion projecting from the wall surface so as to interfere with the convex part fitted into the concave part on the wall surface sandwiching the convex part in the concave part. To do.

  The gist of the invention according to claim 2 is that the protruding portion protrudes from the wall surface with a protruding dimension that is greater than a negative dimensional error allowed for the first layer portion.

  The gist of the invention according to claim 3 is that the protrusion is formed so as to extend from the opening side of the concave portion toward the bottom side of the concave portion.

  The invention according to claim 4 is characterized in that the protruding portion is formed so that the protruding end side is narrower than the root side continuous with the wall surface.

  The gist of the invention according to claim 5 is that the protrusion protrudes from the wall surface extending perpendicularly or at an angle close to vertical in the concave portion that opens downward when the mold is closed.

In order to overcome the above-mentioned problems and achieve the intended purpose, a method for manufacturing a seat pad according to claim 6 of the present application is as follows.
A manufacturing method of a seat pad configured by laminating a first layer portion made of a bead foam and a second layer portion made of a foam different from the first layer portion,
By causing the protrusion protruding from the wall surface of the concave portion on the mold surface of the first mold to interfere with the convex portion on the outer surface of the first layer portion and fitting the convex portion into the concave portion, Attaching one layer part to the first mold,
A raw material is foamed and cured in a cavity defined between the first mold and the second mold which are closed, and is joined to the first layer portion which is attached to the first mold and faces the cavity. The second aspect is to form the second layer portion.
According to the first and sixth aspects of the invention, since the first mold is provided with the protruding portion that protrudes from the wall surface of the concave portion in the mold surface, the first mold is provided in the concave portion of the mold surface in the first mold. When the convex portion of the layer portion is fitted and the first layer portion is attached to the first mold, the protruding portion can be made to interfere with the convex portion. Due to the interference between the first layer portion having elasticity unique to the bead foam and the projection of the first mold, it is possible to prevent the first layer portion attached to the first mold from being dropped or displaced. In particular, even when the first layer portion is smaller than the design size, the first layer portion is absorbed by the dimensional error due to the interference between the protrusion protruding from the mold surface and the first layer portion in the first mold. It can be attached to the first mold. Therefore, it is possible to save time and labor for repairing the first mold in accordance with the dimensional error of the first layer portion, and to efficiently obtain the seat pad. In addition, since the first layer part having elasticity peculiar to the bead foam and the protrusion are caused to interfere with each other, it is difficult to damage the first layer part due to interference with the protrusion.

The gist of the invention according to claim 7 is that the projecting portion is set to project from the wall surface with a projecting dimension equal to or larger than a negative dimensional error set in the first layer portion.
According to the inventions according to claim 2 and claim 7, the convex portions and the protrusions of the first layer portion can be appropriately caused to interfere with each other within the range of the dimensional error, and the first layer with respect to the first mold The part can be attached more securely.

In the invention according to claim 8, the convex portion of the first layer portion interferes with the protrusion formed on the wall surface of the concave portion so as to extend in the insertion direction of the convex portion. The gist is to fit the shape portion into the concave portion.
According to the third and eighth aspects of the invention, since the protrusion is formed so as to extend in the insertion direction of the convex portion into the concave portion, the convex portion of the first layer portion is formed of the first mold. It can be guided when fitting into the concave part. Moreover, after fitting the convex part of a 1st layer part and the concave part of a 1st type | mold, a 1st layer part can be hold | maintained more reliably by interference with a protrusion and a convex part.

In the invention according to claim 9, the convex portion of the first layer portion interferes with the protruding portion formed so that the protruding end side is narrower than the base side continuous with the wall surface, and the convex portion is formed into the concave shape. The gist is to fit in the part.
According to the invention which concerns on Claim 4 and Claim 9, since the protrusion is formed in the tapering shape where the protrusion end side is narrow, when fitting the convex part of the 1st layer part to the concave part of the 1st type The insertion load accompanying the interference of the protrusion can be reduced.

In the invention according to claim 10, the concave portion that opens downward when the mold is closed is formed in a protruding portion that protrudes from the wall surface that extends perpendicularly or at an angle close to the vertical, and the convex portion is formed to match the wall surface. The gist is to make the convex portion fit into the concave portion from below by making the side surfaces interfere with each other.
According to the invention which concerns on Claim 5 and Claim 10, the side surface of a convex part is made to interfere in the convex part which protrudes from the wall surface extended at the angle which is perpendicular | vertical or near perpendicular | vertical in a concave part, and a convex part is fitted to a concave part. Therefore, it is difficult for the convex portion to come off from the concave portion opening downward when the mold is closed, and the first layer portion can be prevented from falling off from the first mold.

  According to the mold according to the present invention, the seat pad can be efficiently molded. According to the seat pad manufacturing method of the present invention, the seat pad can be obtained efficiently.

It is the schematic perspective view which looked at the seat pad concerning the suitable example of the present invention from the slanting upper side. It is the schematic perspective view which looked at the seat pad of the example from the slanting lower side. It is an AA line end view of FIG. FIG. 3 is an end view taken along line BB in FIG. 1. It is explanatory drawing which shows the manufacturing process of the seat pad of an Example. It is explanatory drawing which shows the principal part of the 1st type | mold of an Example. It is a schematic perspective view which shows the principal part of the 1st type | mold of an Example. It is explanatory drawing which shows the manufacturing process of the seat pad of an Example.

  Next, preferred embodiments of the mold and the seat pad manufacturing method according to the present invention will be described below with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, the seat pad 10 according to the embodiment constitutes a seat portion that supports the lower body of the user in the rear seat of the vehicle. As shown in FIGS. 3 and 4, the seat pad 10 is laminated on the first layer portion 12 that mainly constitutes the lower portion of the seat pad 10, and the upper portion of the seat pad 10. The first layer portion 12 and the second layer portion 14 are joined to each other. In the seat pad 10 of the embodiment, the upper surface and the side surface of the outer surface of the seat pad 10 are configured by the second layer portion 14, and most of the lower surface of the outer surface of the seat pad 10 is configured by the first layer portion 12. . In the seat pad 10, the first layer portion 12 and the second layer portion 14 are integrated by the adhesive force of the second layer portion 14 that is formed so as to be in contact with the first layer portion 12.

  The first layer portion 12 is a bead having elasticity such as polypropylene foam (EPP) or polystyrene foam (EPS) obtained by heating and foaming foam beads containing a foaming agent with steam or the like. Consists of foam. The first layer portion 12 is made of a material that is lighter than the material constituting the second layer portion 14. The first layer portion 12 forms a lower surface facing the vehicle body in the seat pad 10, and is formed so that the lower surface is uneven according to the mounting portion of the seat to the vehicle body (see FIG. 2). On the lower surface of the first layer portion 12 of the embodiment, two convex portions 16 projecting downward are provided apart in the longitudinal direction of the seat pad 10.

  The second layer portion 14 is a method of using a chemical reaction such as a gas generated by a polymerization reaction or a foaming agent (chemical reaction gas utilization method), or a method of mixing air such as blowing a gas by mechanical stirring ( A foam obtained by a mechanical mixing method) or the like is used. For the second layer portion 14, a foam different from the bead foam forming the first layer portion 12 is used. For example, a polyurethane foam is employed. Moreover, since the 2nd layer part 14 becomes the user's side sitting on the seat, the soft foam which is more flexible than the 1st layer part 12 is used.

  Next, the shaping | molding die 20 used for shaping | molding of the 2nd layer part 14 which concerns on an Example is demonstrated. As shown in FIG. 5C, the molding die 20 includes a first die 22 to which the first layer portion 12 is attached, and a second die 24 that defines the outer surface of the second layer portion 14, and includes the first die. 22 and the second mold 24 can be opened and closed relatively. The mold 20 according to the embodiment is a lower mold in which the first mold 22 is an upper mold and the second mold 24 is disposed below the first mold 22 when the mold is closed. The first layer portion 12 can be attached to the facing mold surface. The molding die 20 defines a cavity 26 that matches the shape of the second layer portion 14 when the first die 22 and the second die 24 to which the first layer portion 12 is attached are closed (FIG. 8 ( a) and (b)). The molding die 20 foams and hardens the resin raw material (raw material) forming the second layer portion 14 in the cavity 26 and molds the second layer portion 14 with the seat pad 10 turned upside down.

  As shown in FIG. 5 (b), the first mold 22 has a mold surface that can be fitted to at least a part of the unevenness of the lower surface shape of the first layer portion 12 that forms the lower surface of the seat pad 10, and is provided below. A concave portion 28 that opens downward is formed on the facing mold surface in accordance with the convex portion 16 of the first layer portion 12. In the embodiment, the shape of the mold surface of the first mold 22 is formed according to the design shape of the first layer portion 12, and the mold surface is uneven according to the shape of the lower surface of the first layer portion 12. The concave portion 28 is a holding wall surface (wall surface) 28a extending vertically (in the direction of insertion of the convex portion 16 into the concave portion 28) according to the side surface extending in the protruding direction of the convex portion 16 in the first layer portion 12. have. The holding wall surface 28a extends at a vertical or near vertical angle in the concave portion 28 that opens downward when the mold 20 is closed. In the embodiment, the opening side of the concave portion 28 is wider than the bottom side. So that it is slightly inclined. When the first layer portion 12 is attached to the first mold 22 with the convex portion 16 sandwiched between the holding wall surfaces 28a, 28a facing each other, the side surface of the convex portion 16 and the holding wall surface 28a face each other. Here, the angle close to vertical in the holding wall surface 28a may be 10 degrees or less from the vertical direction in the concave portion 28 opening downward, and is preferably 5 degrees or less. If the angle from the vertical direction is 10 degrees or less, it is possible to appropriately prevent the first layer portion 12 attached to the lower surface of the first mold 22 from falling off from the first mold 22. When the angle from the vertical direction exceeds 10 degrees, the first layer portion 12 attached to the lower surface of the first mold 22 is likely to drop off from the first mold 22.

  As shown in FIG. 6, the first mold 22 is provided on the holding wall surface 28 a of the concave portion 28 and protrudes from the holding wall surface 28 a so as to interfere with the side surface of the convex portion 16 that fits into the concave portion 28. Part 30. The protrusion 30 of the embodiment is formed so as to protrude from the holding wall surface 28a with a protrusion dimension that is greater than the negative dimensional error allowed for the first layer part 12. For example, the protrusion dimension of the protrusion 30 may be set to about 1.2 to 2 times the maximum tolerance from the design dimension of the first layer part 12, and more preferably about 1.5 times. The protruding portion 30 of the embodiment is set to have the same protruding dimension from the holding wall surface 28a over the entire length from the opening side of the concave portion 28 opening downward to the bottom (top surface) side of the concave portion 28. .

  As shown in FIG. 7, the protrusion 30 is formed in a long and thin line shape so as to extend from the opening side of the concave portion 28 opening downward to the bottom (top surface) side of the concave portion 28. Although it changes with conditions, such as the magnitude | size of the 1st layer part 12 used as object, it is good to set the width | variety of the protrusion 30 to about 3 mm-15 mm, for example. In the embodiment, in the holding wall surface 28a, the protrusion 30 is formed so as to extend over the entire portion extending from the opening of the recessed portion 28 that is recessed stepwise to the first step of the recessed portion 28. Yes. Further, the protruding portion 30 is formed so that the protruding end side is narrower than the base side continuous with the holding wall surface 28a, and is cut in a direction (horizontal direction in the embodiment) orthogonal to the insertion direction of the protruding portion 16 into the recessed portion 28. For example, the cross-sectional shape is tapered such as a triangular shape (example), a trapezoidal shape, or a semicircular shape.

  As shown in FIG. 7, a plurality of protrusions 30 are arranged on the holding wall surface 28 a side by side in a direction (horizontal direction in the embodiment) orthogonal to the insertion direction of the convex portion 16 into the concave portion 28. The plurality of protrusions 30 may be arranged at a constant interval (example) or in parallel at an appropriate interval, or may be arranged so that adjacent protrusions 30 and 30 are continuous, and the first layer portion that is an interference target They are arranged appropriately according to the conditions such as the size of 12. In each of the two concave portions 28, the first mold 22 is provided with a protrusion 30 on the outer holding wall surface 28a, while the protrusion 30 is formed on the inner holding wall surface 28a facing the outer holding wall surface 28a. Not provided. As described above, the first mold 22 of the embodiment is provided with the protrusions 30 and 30 protruding toward each other so as to interfere with the outer side surfaces of the two convex portions 16 and 16. ing. In addition, even if the protrusion 30 is integrally formed by cutting or the like, the first mold 22 is configured such that the protrusion 30 or a part of the mold surface including the protrusion 30 is detachable from the main body of the first mold 22. May be.

  Next, a method for manufacturing the seat pad 10 using the mold 20 described above will be described. First, a first layer portion 12 obtained by molding into a required shape by a bead foaming method is prepared (FIG. 5A). The convex portion 16 is fitted into the concave portion 28 of the first mold 22, and the first layer portion 12 is attached to the first mold 22 (FIGS. 5B and 6). At this time, the concave portion 28 that opens downward when the mold 20 is closed is aligned with the protrusion 30 protruding from the holding wall surface 28a that extends vertically or at an angle close to the vertical, and the convex portion 16 is aligned with the holding wall surface 28a. The convex portion 16 is fitted into the concave portion 28 from below by causing the side surfaces formed in this manner to interfere with each other. And the protrusion 30 which protrudes from the holding wall surface 28a formed according to the design shape of the 1st layer part 12 interferes with the side surface of the convex-shaped part 16, and the interference part with the protrusion 30 in this side surface is a protrusion. 30 is compressed and elastically deformed, and the convex portion 16 is inserted into the concave portion 28 (FIG. 6B). Thereby, the convex portion 16 of the first layer portion 12 not only fits between the holding wall surfaces 28 a of the concave portion 28, but also the convex portion so that the protrusion 30 bites into the side surface of the convex portion 16. 16 and the concave portion 28 are combined in a state of strong interference (FIG. 6C).

  Next, the resin material forming the second layer portion 14 is supplied to the second mold 24 (FIG. 5C), the first mold 22 and the second mold 24 are closed, and the first mold 22, In the cavity 26 defined by the first layer portion 12 and the second mold 24 attached to the first mold 22, the resin raw material is foamed by heating or the like under predetermined heating conditions (FIG. 8A). Since the first layer portion 12 attached to the first mold 22 faces the cavity 26, the foamed resin material contacts the first layer portion 12, and the resin material is cured in this state. Thereby, the first layer portion 12 attached to the first mold 22 and the second layer portion 14 formed by the cavity 26 are joined and integrated by the adhesive force of the second layer portion 14 itself, A seat pad 10 is obtained (FIG. 8B). Then, the mold 20 is opened, and the obtained seat pad 10 is taken out (FIG. 8C).

  According to the manufacturing method of the mold 20 and the seat pad 10 of the embodiment, the first mold 22 is formed with a mold surface so as to be uneven according to the outer surface of the first layer portion 12, but in the mold surface Since the protrusion 30 protruding from the holding wall surface 28 a of the concave portion 28 is provided, the protrusion 30 interferes with the convex portion 16 when the convex portion 16 of the first layer portion 12 is fitted into the concave portion 28. Can be made. Then, due to the interference between the convex portion 16 of the first layer portion 12 having elasticity unique to the bead foam and the protrusion 30 of the first die 22, the first layer portion 12 attached to the first die 22 is dropped or positioned. Misalignment can be prevented. In particular, even when the first layer portion 12 is smaller than the design size, a dimensional error occurs due to interference between the protrusion 30 protruding from the mold surface and the convex portion 16 of the first layer portion 12 in the first mold 22. The first layer portion 12 can be attached to the first mold 22 by absorbing the water. Accordingly, it is possible to save time and labor for repairing the first mold 22 in accordance with the dimensional error of the first layer portion 12 and the change in dimensional accuracy due to the season, and the seat pad 10 can be obtained efficiently. Further, since the first layer portion 12 having elasticity unique to the bead foam and the protrusion 30 are caused to interfere with each other, the interference with the protrusion 30 makes it difficult to damage the first layer portion 12 such as chipping or cracking.

  Since the protruding portion 30 protrudes from the holding wall surface 28a with a protruding dimension that is equal to or larger than the negative dimensional error set in the first layer portion 12, if the first layer portion 12 is within the allowable dimensional error range, The convex part 16 and the protrusion 30 of the first layer part 12 can be made to interfere appropriately. Therefore, even if a dimensional error of the first layer portion 12 or a change in the dimensional accuracy due to the season occurs, the first layer portion 12 is made more than the first mold 22 due to the interference between the protrusion 30 and the convex portion 16. Can be attached securely.

  Since the protrusion 30 is formed so as to extend in the insertion direction of the convex portion 16 to the concave portion 28, when the convex portion 16 of the first layer portion 12 is fitted to the concave portion 28 of the first mold 22. Further, the convex portion 16 can be guided by the protrusion 30. Further, after the convex portion 16 of the first layer portion 12 and the concave portion 28 of the first mold 22 are fitted together, the protrusion 30 and the convex portion 16 extending in the protruding direction of the convex portion 16 are relatively wide. Since interference occurs over a range, the first layer portion 12 can be more reliably attached to the first mold 22.

  Since the protrusion 30 is formed in a tapered shape with a narrow protruding end side, when the convex portion 16 of the first layer portion 12 is fitted to the concave portion 28 of the first mold 22, interference with the protrusion 30 is caused. The accompanying insertion load can be reduced.

  According to the manufacturing method of the molding die 20 and the seat pad 10 of the embodiment, the side surface of the convex portion 16 is caused to interfere with the protrusion 30 protruding from the holding wall surface 28a extending at a vertical angle or near vertical angle in the concave portion 28, The convex portion 16 is fitted into the concave portion 28. Thereby, interference with the convex part 16 of the protrusion 30 and the 1st layer part 12 can be made to act suitably in the direction which pinches the convex part 16 between holding | maintenance wall surface 28a, 28a. Accordingly, the convex portion 16 can be more easily removed from the concave portion 28 that opens downward when the mold 20 is closed, and from the first mold 22 of the first layer portion 12 attached to the lower surface of the first mold 22. Can be prevented appropriately.

(Example of change)
The present invention is not limited to the configuration described above, and can be modified as follows, for example.
(1) The protruding portion of the embodiment has a shape in which the protruding end side becomes narrow, but is not limited thereto, and may have the same width from the root side to the protruding end. Moreover, even if it is a protrusion of the shape where a protrusion end side becomes thin, not only the shape which becomes narrow gradually as it goes to the protrusion end side, but the shape where the protrusion end side becomes narrow stepwise may be sufficient.
(2) In the embodiment, the protrusion is provided so as to extend from the opening side to the bottom side of the concave portion. However, the present invention is not limited thereto, and the protrusion may be provided in a protruding shape instead of a linear shape. In addition, the protrusions may be arranged on the opening side of the concave part, on the bottom side of the concave part, in the middle part of the concave part, or in multiple places. May be. In the case where the protrusions are arranged at a plurality of locations, the protrusion dimensions from the wall surface may be increased toward the bottom side of the concave portion even if the protrusion dimensions are the same at all the arrangement positions.
(3) In the embodiment, the width of the protrusion is formed to be the same from the opening side to the bottom side. However, the present invention is not limited to this. For example, the bottom side may be formed wider than the opening side. In other words, in the embodiment, the protrusion is formed so as to extend in the vertical direction from the opening side of the concave portion toward the bottom side, but, for example, as the concave portion opens from the opening side to the bottom side, You may make it incline linearly or curvilinearly so that one or both may leave | separate from the other. When it inclines linearly, the inclination angle of the side surface of the protrusion may be the same from the opening side to the bottom side of the concave part, or may change in the middle.
(4) In the embodiment, the projecting dimension of the protrusion from the holding wall surface is the same from the opening side to the bottom side. However, the present invention is not limited to this, and for example, the bottom side protrudes greatly from the holding wall surface from the opening side. It may be. Moreover, it is good also considering the edge part used as the opening side of the recessed part in a protrusion as a taper shape where the protrusion dimension of an opening side becomes small.
(5) In the embodiment, the protrusion is arranged so as to extend linearly in the insertion direction of the convex portion into the concave portion, but not limited to this, the protrusion is inclined so as to intersect the insertion direction. You may arrange. In this case, the extending direction from the opening side to the bottom side of the concave portion in the protrusion may be the same from the opening side to the bottom side of the concave portion, or may change in the middle, and the insertion direction You may change an angle on the way after extending to. Furthermore, adjacent protrusions may be arranged in a “C” shape that opens on the opening side of the concave portion, or may be arranged in an inverted “C” shape that narrows the opening side of the concave portion.
(6) Although the protrusions are provided on the outer holding wall surface for each of the two concave portions of the first type in the embodiment, the protrusions may be disposed on at least one wall surface of the plurality of concave portions. Further, it is only necessary to place a protrusion on the wall surface of any one of the concave portions corresponding to the periphery of the convex portion of the first layer portion. For example, in the concave portion of the embodiment, the protrusion is formed on the inner holding wall surface. It may be provided.

10 seat pads, 12 first layer part, 14 second layer part, 16 convex part, 22 first type,
24 Second mold, 26 cavity, 28 concave portion, 28a Retaining wall surface (wall surface)

Claims (10)

Of the seat pad configured by laminating a first layer portion made of a bead foam and a second layer portion made of a foam different from the first layer portion, the second layer portion is the first layer portion. A mold that is molded so as to be joined to a layer part,
A first mold to which the first layer part can be attached by fitting the convex part on the outer surface of the first layer part and the concave part formed on the mold surface;
By closing the mold with the first mold, a second mold that defines a cavity matched to the second layer portion between the first mold and the first layer portion attached to the first mold. Prepared,
The first mold has a protrusion projecting from the wall surface so as to interfere with the convex portion fitted into the concave portion on a wall surface sandwiching the convex portion in the concave portion. Mold to be used.   2. The mold according to claim 1, wherein the protruding portion protrudes from the wall surface with a protruding dimension that is greater than a negative dimensional error allowed for the first layer portion.   The mold according to claim 1 or 2, wherein the protrusion is formed so as to extend from an opening side of the concave portion toward a bottom side of the concave portion.   The said protrusion is a shaping | molding die as described in any one of Claims 1-3 in which the protrusion end side is formed more narrowly than the root side connected to the said wall surface.   5. The molding die according to claim 1, wherein the projecting portion projects from the wall surface extending at a vertical or near vertical angle in the concave portion that opens downward when the die is closed. A manufacturing method of a seat pad configured by laminating a first layer portion made of a bead foam and a second layer portion made of a foam different from the first layer portion,
By causing the protrusion protruding from the wall surface of the concave portion on the mold surface of the first mold to interfere with the convex portion on the outer surface of the first layer portion and fitting the convex portion into the concave portion, Attaching one layer part to the first mold,
The raw material is foamed and cured in a cavity defined between the first mold and the second mold which are closed, and is attached to the first mold and joined to the first layer portion facing the cavity. A method for manufacturing a seat pad, comprising: forming the second layer portion.   The method of manufacturing a seat pad according to claim 6, wherein the protrusion is set so as to protrude from the wall surface with a protrusion dimension equal to or greater than a negative dimensional error set in the first layer part.   The convex portion of the first layer portion is caused to interfere with the protrusion formed on the wall surface of the concave portion so as to extend in the insertion direction of the convex portion, and the convex portion is fitted into the concave portion. A method for manufacturing a seat pad according to claim 6 or 7.   The projecting part of the first layer part and the projecting part formed so that the protruding end side is narrower than the base side connected to the wall surface interfere with each other, and the projecting part is fitted into the recessed part. The manufacturing method of the seat pad as described in any one of Claims 8.   In the concave portion that opens downward when the mold is closed, a protrusion projecting from the wall surface extending at an angle that is perpendicular or nearly perpendicular to the protruding portion is caused to interfere with a side surface formed to match the wall surface in the convex portion, The manufacturing method of the seat pad as described in any one of Claims 6-9 which inserts a convex part in this concave part from the downward direction.

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