Mold for molding seat pad and method for manufacturing seat pad

Abstract

To prevent occurrence of burrs.SOLUTION: There is provided a mold 24 for molding a seat pad, comprising an upper mold 28 having a first through-hole forming portion 34 and a lower mold 30 having a second through-hole forming portion. The first through-hole forming portion 34 protrudes from the upper mold 28 toward the lower mold 30, and is disposed at a position corresponding to a part of the through-hole in a space where the seat pad is formed. The second through-hole forming portion 38 protrudes from the lower mold 30 toward the upper mold 28, and is disposed at a position corresponding to another part of the through-hole in a space where the seat pad is formed. Further, when the upper mold 28 and the lower mold 30 are engaged, a surface 38A of the second through-hole forming portion 38 at a tip end side in a protruding direction is in vertically contact with a surface 34A of the first through-hole forming portion 34 at a tip end side in the protruding direction. Furthermore, the second through-hole forming portion 38 is formed in such a shape that at least an upper end portion thereof is widen horizontally as it extends upwards when viewed in cross-section after being cut along the vertical axis.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a mold for molding a seat pad and a method for manufacturing a seat pad. [Background technology]

[0002] Patent Document 1 below discloses a seat pad for use in a vehicle seat and a method for manufacturing the seat pad. The seat pad described in this document has recesses formed on the front and rear surfaces of a foam molded body, and the bottom surfaces of these two recesses form flash portions. The peripheral edge of the flash portion is a thin portion with a small thickness, and the central portion of the flash portion is a thick portion that is thicker than the thin portion. In this configuration, an operator inserts a finger into one of the recesses and presses the thick portion of the flash portion. This concentrates stress in the thin portion of the flash portion, causing the thin portion to break. This makes it possible to separate the flash portion from the foam molded body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-45548 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, although the invention described in Patent Document 1 above has a useful configuration from the viewpoint of easily removing unnecessary parts such as burrs, it is conceivable that part of the broken thin-walled part will remain on the seat pad as a burr (thin film).

[0005] In consideration of the above, an object of the present invention is to provide a mold for molding a seat pad and a method for manufacturing a seat pad that can suppress the generation of burrs. [Means for solving the problem]

[0006] The first aspect of the seat pad molding mold is a seat pad molding mold for molding a seat pad having a through hole formed therein that penetrates from the seated occupant side to the opposite side from the seated occupant, and comprises an upper mold and a lower mold that engage in an up-down direction to form a space inside which the seat pad is formed, a first through hole forming portion that protrudes from the upper mold toward the lower mold and is positioned at a position corresponding to a part of the through hole in the space where the seat pad is formed, and a second through hole forming portion that protrudes from the lower mold toward the upper mold and is positioned at a position corresponding to another part of the through hole in the space where the seat pad is formed, and when the upper mold and the lower mold are engaged, the surface at the tip end side in the protruding direction contacts the surface at the tip end side in the protruding direction of the first through hole forming portion in an up-down direction, and when viewed in a cross section cut along the up-down direction, at least its upper end portion is formed in a shape that expands horizontally as it moves upward.

[0007] In the mold for molding a seat pad of the first embodiment, for example, a seat pad can be molded by the following procedure. First, a seat pad material is poured into the lower part of the lower mold. Next, the upper mold and the lower mold are engaged. Next, the seat pad material is foamed between the upper mold and the lower mold, filling the space between the upper mold and the lower mold with the seat pad material. Through these steps, a seat pad can be molded. Here, in the mold for molding a seat pad of the first embodiment, when the upper mold and the lower mold are engaged, the surface on the tip side of the protruding direction of the second through-hole forming portion is in vertical contact with the surface on the tip side of the protruding direction of the first through-hole forming portion. Furthermore, in a cross-sectional view cut along the vertical direction, at least the upper end of the second through-hole forming portion is formed in a shape that widens horizontally as it moves upward. With this configuration, the material of the seat pad being foamed from the lower mold side to the upper mold side is repelled along the upper end of the second through-hole forming portion and is less likely to move toward the boundary between the first and second through-hole forming portions, thereby making it possible to prevent burrs from being generated by the material of the seat pad being foamed getting into the boundary between the first and second through-hole forming portions.

[0008] The second embodiment of the mold for molding a seat pad is the mold for molding a seat pad of the first embodiment, in which the protruding end of the second through-hole forming portion is formed larger than the protruding end of the first through-hole forming portion, so that when the upper mold and the lower mold are engaged, a step is formed at the boundary between the first through-hole forming portion and the second through-hole forming portion.

[0009] In the second aspect of the seat pad molding die, when the upper and lower dies are engaged, a step is formed at the boundary between the first through-hole forming portion and the second through-hole forming portion. This configuration makes it possible to prevent the seat pad material, which is repelled along the upper end of the second through-hole forming portion, from entering the boundary between the first and second through-hole forming portions, compared to a configuration in which the step is not formed at the boundary between the first and second through-hole forming portions.

[0010] The third embodiment of the mold for molding a seat pad is the mold for molding a seat pad of the second embodiment, in which the dimension of the step in a direction perpendicular to the direction in which the surface at the tip end of the protruding direction of the first through-hole forming portion and the surface at the tip end of the protruding direction of the second through-hole forming portion contact is set in the range of 2 mm or more and 6 mm or less.

[0011] In the third embodiment of the mold for molding a seat pad, compared to a configuration in which the difference in dimension of the step formed at the boundary between the first through hole forming portion and the second through hole forming portion is set outside the above range, it is possible to prevent the material of the seat pad that has been repelled along the upper end of the second through hole forming portion from entering the boundary between the first through hole forming portion and the second through hole forming portion.

[0012] The fourth aspect of the seat pad molding mold is a seat pad molding mold for molding a seat pad having a through hole formed therein that penetrates from the seated occupant side to the opposite side from the seated occupant, and comprises upper and lower molds that engage in an up-down direction to form a space inside which the seat pad is formed, a first through hole forming portion that protrudes from the upper mold toward the lower mold and is positioned at a position corresponding to a part of the through hole in the space where the seat pad is formed, and a second through hole forming portion that protrudes from the lower mold toward the upper mold and is positioned at a position corresponding to another part of the through hole in the space where the seat pad is formed, and when the upper mold and the lower mold are engaged, the surface at the tip of the protruding direction of the first through hole forming portion is in up-down contact with the surface at the tip of the protruding direction of the first through hole forming portion, and when viewed in a cross section cut along the up-down direction, the surface at the tip of the protruding direction of the first through hole forming portion and the surface at the tip of the protruding direction of the second through hole forming portion are inclined downward as they approach the center of the through hole.

[0013] In the fourth embodiment of the mold for molding a seat pad, a seat pad can be molded, for example, by the following procedure. First, a seat pad material is poured into the lower part of the lower mold. Next, the upper and lower molds are engaged. Next, the seat pad material is foamed between the upper and lower molds to fill the space between the upper and lower molds with the seat pad material. Through these steps, a seat pad can be molded. Here, in the fourth embodiment of the mold for molding a seat pad, when the upper and lower molds are engaged, the surface at the tip of the second through-hole forming portion in the protruding direction is in vertical contact with the surface at the tip of the first through-hole forming portion in the protruding direction. Furthermore, in a cross-sectional view cut along the vertical direction, the surface at the tip of the first through-hole forming portion in the protruding direction and the surface at the tip of the second through-hole forming portion in the protruding direction are inclined downward toward the center of the through hole. Here, the seat pad material is foamed upward from the lower mold side to the upper mold side. Therefore, in a configuration in which the surface of the first through-hole forming portion at the tip end in the protruding direction and the surface of the second through-hole forming portion at the tip end in the protruding direction are inclined downward as they approach the center of the through hole, the material of the seat pad moving upward is less likely to seep into the boundary between the first through-hole forming portion and the second through-hole forming portion, thereby making it possible to suppress the generation of burrs caused by the material of the seat pad in the foaming process seeingp into the boundary between the first through-hole forming portion and the second through-hole forming portion.

[0014] A method for manufacturing a seat pad of the fifth aspect uses a mold for molding a seat pad of any one of the first to fourth aspects, and includes a material injection process for injecting material for the seat pad into the lower part of the lower mold, a mold engagement process for engaging the upper mold and the lower mold, and a foaming process for foaming the material for the seat pad between the upper mold and the lower mold to fill the space between the upper mold and the lower mold with the material for the seat pad.

[0015] In the method for manufacturing a seat pad of the fifth aspect, first, the material for the seat pad is poured into the lower part of the lower mold (material pouring step). Next, the upper mold and the lower mold are engaged (mold engagement step). Next, the material for the seat pad is foamed between the upper mold and the lower mold, and the space between the upper mold and the lower mold is filled with the material for the seat pad (foaming step). Here, in the method for manufacturing a seat pad of the fifth aspect, a mold for molding a seat pad of any one of the first to fourth aspects is used. This makes it possible to prevent the material for the seat pad from entering the boundary between the first through-hole forming portion and the second through-hole forming portion during the foaming process, thereby preventing burrs from occurring. [Effects of the Invention]

[0016] The mold for molding a seat pad and the method for manufacturing a seat pad according to the present invention have the excellent effect of being able to suppress the generation of burrs. [Brief explanation of the drawings]

[0017] [Figure 1] 4 is a side cross-sectional view showing a cross section of the cushion pad taken along the seat front-rear direction and the up-down direction. FIG. [Figure 2] FIG. 4 is a side cross-sectional view showing the cushion pad, illustrating an enlarged portion where a through hole is formed. [Figure 3] 2 is a side cross-sectional view schematically showing a cross section of a mold for molding a seat pad taken along the vertical direction. FIG. [Figure 4] 4 is a side cross-sectional view corresponding to FIG. 3 for explaining a material charging step and a mold engaging step. FIG. [Figure 5] FIG. 4 is a cross-sectional side view corresponding to FIG. 3 for explaining a foaming step. [Figure 6] 10 is a side cross-sectional view schematically showing a cross section of another type of mold for molding a seat pad taken along the vertical direction. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] FIG. 1 shows a cross section of a cushion pad 10 as a seat pad molded using a seat pad molding die 24 (see FIG. 3 ), which will be described later. The cushion pad 10 constitutes part of a seat cushion that supports the buttocks of a seated occupant from the underside of the seat, and is made of polyurethane foam, a type of foam resin. More specifically, the cushion pad 10 includes a main portion 12 that constitutes a central portion in the seat width direction, and a pair of left and right side support portions 14 that constitute both sides of the seat width direction. The main portion 12 extends in the seat width direction and the seat front-rear direction. The main portion 12 has a plurality of through holes 16 formed therein, penetrating from the seated occupant side (arrow A1 side) to the opposite side from the seated occupant (arrow A2 side). Note that only one through hole 16 is shown in the cross section shown in FIG. 1. These multiple through holes 16 function as holes through which air is blown toward the seated occupant side or air is sucked from the seated occupant side. The pair of left and right side support portions 14 extend in the front-rear direction of the seat on both sides of the main portion 12 in the seat width direction, and protrude upward from the main portion 12 toward the seat.

[0019] As shown in FIG. 2 , the through hole 16 includes a first through hole 18 and a second through hole 20, each having a different inner peripheral surface configuration. The portion of the through hole 16 opposite the seated occupant is the first through hole 18. Most of the inner surface of the first through hole 18, excluding the end portion opposite the seated occupant, is cylindrical. The inner diameter B1 of most of the first through hole 18, excluding the end portion opposite the seated occupant, is constant along the axial direction of the through hole 16. On the other hand, the portion of the through hole 16 facing the seated occupant is the second through hole 20. The second through hole 20 is coaxial with the first through hole 18 and is connected to the first through hole 18. Most of the inner surface of the second through hole 20, excluding the end portion facing the seated occupant, is cylindrical and gradually widens toward the first through hole 18. Moreover, the inner diameter B2 of most of the second through hole 20 excluding the end on the seated occupant side gradually increases toward the first through hole 18. Furthermore, the inner diameter B2 of the second through hole 20 at the connection with the first through hole 18 is larger than the inner diameter B1 of the first through hole 18. As a result, a step 22 having a difference in dimension in the radial direction of the through hole 16 is formed at the boundary between the first through hole 18 and the second through hole 20.

[0020] 3 shows a cross section of a mold 24 for molding a seat pad (hereinafter simply referred to as "mold 24") cut along the axial direction of a first through-hole forming portion 34 and a second through-hole forming portion 38, which will be described later. The arrow UP shown in the figure indicates the upper side of the location where the mold 24 is installed. As shown in FIG. 3, the mold 24 is configured to include an upper mold 28 and a lower mold 30 that engage with each other in the vertical direction to form a space 26 inside which the cushion pad 10 (see FIG. 1) is formed.

[0021] The upper mold 28 includes an upper wall portion 32 whose inner surface is formed in a shape that conforms to the surface of the cushion pad 10 on the side opposite to the seated occupant, and a plurality of first through-hole forming portions 34 that protrude downward (toward the lower mold 30) from the upper wall portion 32. Note that FIG. 3 shows one first through-hole forming portion 34. These plurality of first through-hole forming portions 34 are respectively disposed at positions corresponding to the first through holes 18 of the plurality of through holes 16 in the space 26 in which the cushion pad 10 is formed. Furthermore, the shape of the first through-hole forming portion 34 is formed in a shape that corresponds to the internal shape of the first through hole 18. Specifically, the shape of the outer surface of most of the first through-hole forming portion 34 excluding the end portion on the upper wall portion 32 side is formed in a cylindrical shape. Furthermore, the outer diameter C1 of most of the first through-hole forming portion 34 excluding the end portion on the upper wall portion 32 side is a constant inner diameter along the protruding direction of the first through-hole forming portion 34. Furthermore, a surface 34A on the tip side in the protruding direction of the first through-hole forming portion 34 is formed in a flat shape.

[0022] The lower mold 30 includes a lower wall portion 36 whose inner surface is formed in a shape that conforms to the surface of the cushion pad 10 facing the seated occupant, and a plurality of second through-hole forming portions 38 that protrude upward (toward the upper mold 28) from the lower wall portion 36. Note that FIG. 3 shows one second through-hole forming portion 38. These second through-hole forming portions 38 are respectively disposed at positions corresponding to the second through-holes 20 of the plurality of through-holes 16 in the space 26 in which the cushion pad 10 is formed, and are respectively disposed coaxially with the plurality of first through-hole forming portions 34 when the upper mold 28 and the lower mold 30 are engaged. Furthermore, the shape of the second through-hole forming portion 38 is formed in a shape that corresponds to the internal shape of the second through-hole 20. Specifically, the shape of most of the outer surface of this second through-hole forming portion 38, excluding the end portion on the lower wall portion 36 side, is formed in a cylindrical shape that gradually widens toward the upward side (toward the first through-hole forming portion 34). The outer diameter C2 of most of the second through-hole forming portion 38, excluding the end portion on the lower wall portion 36 side, gradually increases toward the first through-hole forming portion 34 side. Furthermore, the outer diameter C2 at the tip of the second through-hole forming portion 38 in the protruding direction is larger than the outer diameter C1 at the tip of the first through-hole forming portion 34 in the protruding direction. Furthermore, a surface 38A at the tip of the second through-hole forming portion 38 in the protruding direction is formed flat. When the upper mold 28 and the lower mold 30 are engaged, the surface 38A at the tip of the second through-hole forming portion 38 in the protruding direction and the surface 34A at the tip of the first through-hole forming portion 34 in the protruding direction are in contact with each other in the vertical direction. When the upper mold 28 and the lower mold 30 are engaged, a step 40 is formed at the boundary between the first through-hole forming portion 34 and the second through-hole forming portion 38. Furthermore, the dimension D of the step 40 in a direction perpendicular to the direction in which the surface 34A at the tip end of the protruding direction of the first through-hole forming portion 34 and the surface 38A at the tip end of the protruding direction of the second through-hole forming portion 38 contact each other is set in the range of 2 mm or more and 6 mm or less.

[0023] (Actions and Effects of This Embodiment) Next, the operation and effects of this embodiment will be described.

[0024] The above-described mold 24 can mold the cushion pad 10 through the following steps.

[0025] First, as shown in Fig. 4, the material 42 of the cushion pad 10 is poured into a predetermined position and range on the lower wall portion 36 that constitutes the lower part of the lower mold 30 (material pouring step). Next, the upper mold 28 and the lower mold 30 are engaged (mold engaging step). Next, the material 42 of the cushion pad 10 is foamed between the upper mold 28 and the lower mold 30, and as shown in Fig. 5, the space 26 between the upper mold 28 and the lower mold 30 is filled with the material 42 of the cushion pad 10. Through these steps, the cushion pad 10 can be molded.

[0026] In this embodiment, when the upper mold 28 and the lower mold 30 are engaged, a surface 38A of the second through-hole forming portion 38 at the tip end in the protruding direction is in vertical contact with a surface 34A of the first through-hole forming portion 34 at the tip end in the protruding direction. In a cross-sectional view cut along the vertical direction, the outer diameter C2 of most of the second through-hole forming portion 38, excluding the end portion on the lower wall portion 36 side, gradually increases toward the first through-hole forming portion 34. This results in an upper portion 38B of the second through-hole forming portion 38 having a shape that widens horizontally as it extends upward. In other words, the outer surface of the upper portion 38B of the second through-hole forming portion 38 forms an inclined surface 38C that slopes upward in a direction away from the axis of the second through-hole forming portion 38. With this configuration, the material 42 of the cushion pad 10 in the process of foaming from the lower mold 30 side toward the upper mold 28 side is repelled along the inclined surface 38C of the second through hole forming portion 38, and is less likely to move toward the boundary between the first through hole forming portion 34 and the second through hole forming portion 38. This makes it possible to prevent the material of the cushion pad 10 in the process of foaming from getting into the boundary between the first through hole forming portion 34 and the second through hole forming portion 38, thereby preventing burrs from being generated.

[0027] Furthermore, in the present embodiment, when the upper mold 28 and the lower mold 30 are engaged with each other, a step 40 is formed at the boundary between the first through hole forming portion 34 and the second through hole forming portion 38. In this configuration, compared to a configuration in which the step 40 is not formed at the boundary between the first through hole forming portion 34 and the second through hole forming portion 38, it is possible to prevent the material 42 of the cushion pad 10, which has been repelled along the inclined surface 38C of the second through hole forming portion 38, from entering the boundary between the first through hole forming portion 34 and the second through hole forming portion 38. Here, the inventor of the present application confirmed through prototyping and simulation that by setting the dimension D of the step 40 in a direction perpendicular to the direction in which the surface 34A at the tip end of the protruding direction of the first through-hole forming portion 34 and the surface 38A at the tip end of the protruding direction of the second through-hole forming portion 38 contact each other to a range of 2 mm or more and 6 mm or less, it is possible to prevent the material 42 of the cushion pad 10, which has been repelled along the inclined surface 38C of the second through-hole forming portion 38, from entering the boundary between the first through-hole forming portion 34 and the second through-hole forming portion 38.

[0028] (Molds for molding other types of seat pads 44) Next, a mold 44 for molding a seat pad of another embodiment (hereinafter simply referred to as "mold 44") will be described with reference to Figure 6. Note that parts of the mold 44 of this embodiment corresponding to those of the mold 24 described above will be given the same reference numerals as those of the mold 24, and their description may be omitted.

[0029] 6, in the mold 44 of this embodiment, the protruding direction tip 34B of the first through-hole forming portion 34 is formed into a truncated cone shape that narrows downward. Furthermore, in the mold 44 of this embodiment, the protruding direction tip 38D of the second through-hole forming portion 38 is formed with a fitting recess 38E into which the protruding direction tip 34B of the first through-hole forming portion 34 fits. As a result, the outer periphery of the surface 34A on the protruding direction tip side of the first through-hole forming portion 34 and the outer periphery of the surface 38A on the protruding direction tip side of the second through-hole forming portion 38 form inclined surfaces 34A1 and 38A1 that slope downward toward the center of the through hole 16 (the axial sides of the first through-hole forming portion 34 and the second through-hole forming portion 38). In this embodiment, the outer diameter C1 of the first through-hole forming portion 34 and the outer diameter C2 of the second through-hole forming portion 38 are the same in the axial direction.

[0030] Incidentally, the material 42 of the cushion pad 10, which is being foamed from the lower mold 30 side to the upper mold 28 side, moves upward. Therefore, in a configuration in which the inclined surface 34A1 of the first through-hole forming portion 34 and the inclined surface 38A1 of the second through-hole forming portion 38 are inclined downward as they move toward the center of the through hole 16, the material 42 of the cushion pad 10, which is moving upward, is less likely to enter the boundary between the inclined surface 34A1 of the first through-hole forming portion 34 and the inclined surface 38A1 of the second through-hole forming portion 38. This makes it possible to prevent burrs from occurring when the material 42 of the cushion pad 10, which is being foamed, enters the boundary between the first through-hole forming portion 34 and the second through-hole forming portion 38.

[0031] Although one embodiment of the present invention has been described above, the present invention is not limited to the above and can be implemented in various other modifications without departing from the spirit of the present invention. For example, the configurations of the molds 24 and 44 described above can be combined with each other. Furthermore, the configurations of the molds 24 and 44 described above can also be applied to molds for manufacturing back pads and headrest pads as seat pads. [Explanation of symbols]

[0032] 10 Cushion pad (seat pad) 16 through holes 24 Seat pad molding mold 26 Space in which the seat pad is formed 28 Upper mold 30 Lower mold 34 First through hole forming part 34A: Surface at the tip end of the first through-hole forming portion in the protruding direction 38 Second through hole forming part 38A: Surface of the tip side of the second through-hole forming portion in the protruding direction 40 steps 44 Seat pad molding mold

Claims

1. A mold for molding a seat pad, the mold being for molding a seat pad having a through hole formed therein that penetrates from a seated occupant side to an opposite side from the seated occupant, an upper mold and a lower mold that are engaged with each other in the vertical direction to form a space in which the seat pad is formed; a first through-hole forming portion that protrudes from the upper mold toward the lower mold and is disposed at a position corresponding to a part of the through-hole in a space where the seat pad is formed; a second through-hole forming portion that protrudes from the lower mold toward the upper mold, is disposed at a position corresponding to another part of the through-hole in the space where the seat pad is formed, and when the upper mold and the lower mold are engaged, the surface at the tip of the protruding direction contacts the surface at the tip of the protruding direction of the first through-hole forming portion in the vertical direction, and is formed in a shape such that at least its upper end portion widens horizontally as it moves upward in a cross-sectional view cut along the vertical direction; A mold for molding seat pads.

2. A mold for molding a seat pad as described in claim 1, wherein the protruding end of the second through hole forming portion is formed larger than the protruding end of the first through hole forming portion, so that when the upper mold and the lower mold are engaged, a step is formed at the boundary between the first through hole forming portion and the second through hole forming portion.

3. A mold for molding a seat pad as described in claim 2, wherein the dimension of the step in a direction perpendicular to the direction in which the surface at the tip end of the protruding direction of the first through hole forming portion and the surface at the tip end of the protruding direction of the second through hole forming portion contact is set in the range of 2 mm or more and 6 mm or less.

4. A mold for molding a seat pad, the mold being for molding a seat pad having a through hole formed therein that penetrates from a seated occupant side to an opposite side from the seated occupant, an upper mold and a lower mold that are engaged with each other in the vertical direction to form a space in which the seat pad is formed; a first through-hole forming portion that protrudes from the upper mold toward the lower mold and is disposed at a position corresponding to a part of the through-hole in a space where the seat pad is formed; a second through-hole forming portion that protrudes from the lower mold toward the upper mold, is disposed at a position corresponding to another part of the through-hole in the space where the seat pad is formed, and has a surface at a tip end in the protruding direction that contacts in the up-and-down direction with a surface at a tip end in the protruding direction of the first through-hole forming portion when the upper mold and the lower mold are engaged; Equipped with A mold for molding a seat pad, in which, when viewed in cross section along the vertical direction, the surface at the tip end of the protruding direction of the first through-hole forming portion and the surface at the tip end of the protruding direction of the second through-hole forming portion are inclined downward as they approach the center of the through hole.

5. Using the mold for molding a seat pad according to any one of claims 1 to 4, a material introduction step of introducing a material for the seat pad into a lower portion of the lower mold; a mold engaging step of engaging the upper mold with the lower mold; a foaming step of foaming a material for the seat pad between the upper mold and the lower mold to fill a space between the upper mold and the lower mold with the material for the seat pad; A method for manufacturing a seat pad having the above structure.

Images