JP7494036B2 - Cushion body and manufacturing method of cushion body - Google Patents

Description

The present invention relates to a cushion body and a method for manufacturing a cushion body.

2. Description of the Related Art Conventionally, a porous structure having cushioning properties (such as urethane foam) has been produced through a process of foaming by chemical reaction, for example, in a mold molding process.
Meanwhile, in recent years, there have been proposals for porous structures that can be easily manufactured using a 3D printer to provide cushioning properties (for example, Patent Documents 1 and 2).

Patent Publication No. WO2019/235544 Patent Publication No. WO2019/235547

The inventors of the present invention conducted extensive research into a cushioning body that would provide dynamic properties different from those obtained from the porous structure alone, and came up with the present invention.

The present invention aims to provide a cushion body capable of obtaining dynamic characteristics different from those obtained from a porous structure alone, and a method for manufacturing a cushion body capable of obtaining a cushion body capable of obtaining dynamic characteristics different from those obtained from a porous structure alone.

The cushion body of the present invention is
A porous structure made of a flexible resin or rubber;
A first bag body that defines a first space therein;
Equipped with
The first bag contains the porous structure and is filled with a viscous fluid.
The porous structure has a skeleton throughout its entirety,
The skeleton portion is
A plurality of bones;
a plurality of connecting portions each connecting an end portion of the plurality of bone portions to each other;
It is composed of:
According to the cushion body of the present invention, it is possible to obtain dynamic characteristics different from those obtainable from only the porous structure.

In the cushion body of the present invention,
A second bag body that defines a second space therein; and
an orifice partition that defines an orifice that communicates the first space and the second space;
It is preferable that the device further comprises:
This makes it easier to obtain dynamic properties that are different from those obtainable from the porous structure alone.

In the cushion body of the present invention,
The first bag is preferably integral with the porous structure or is bonded to the porous structure.
This makes it easier to obtain dynamic properties that are different from those obtainable from the porous structure alone.

In the cushion body of the present invention,
the skeleton has a plurality of cell partitions that partition cell pores therein,
Each of the cell partitions has a plurality of annular portions each configured in an annular shape,
the plurality of annular portions constituting the cell partition are connected to each other such that imaginary planes defined by the respective inner circumferential side edges do not intersect with each other,
Each of the annular portions is composed of a plurality of the bone portions and a plurality of the connecting portions,
Each of the virtual surfaces is flat,
It is preferable that the cell holes are defined by the plurality of annular portions and the plurality of imaginary surfaces defined by the plurality of annular portions, respectively.
This can improve the cushioning properties of the porous structure.

In the cushion body of the present invention,
the plurality of annular portions constituting the cell partition portion include one or more small annular portions and one or more large annular portions,
Each of the small annular portions defines a small imaginary flat surface by its inner peripheral edge,
It is preferable that each of the large annular portions defines, by its inner peripheral edge, a large imaginary surface which is flat and has an area larger than that of the small imaginary surface.
This can improve the cushioning properties of the porous structure.

In the cushion body of the present invention,
It is preferable that the small imaginary surface and the large imaginary surface have shapes different from each other.
This can improve the cushioning properties of the porous structure.

In the cushion body of the present invention,
It is preferable that each of the cell holes has a shape of a substantially Kelvin tetrahedron.
This can improve the cushioning properties of the porous structure.

In the cushion body of the present invention,
The cushion body is preferably used in a seat pad.

In the cushion body of the present invention,
It is preferable that the portion of the cushion body other than the viscous fluid is formed by a 3D printer.

The method for manufacturing a cushion body of the present invention includes the steps of:
The cushion body is manufactured using a 3D printer.
According to the method for producing a cushion body of the present invention, it is possible to obtain a cushion body that is capable of obtaining dynamic characteristics different from the dynamic characteristics obtained from only a porous structure.

The present invention provides a cushion body capable of obtaining dynamic characteristics different from those obtained from a porous structure alone, and a method for producing a cushion body capable of obtaining a cushion body capable of obtaining dynamic characteristics different from those obtained from a porous structure alone.

1 is a perspective view showing a cushion body according to a first embodiment of the present invention in a state in which no load is input; 2 is a cross-sectional view showing the cushion body of FIG. 1 in a state where no load is input. FIG. FIG. 3 is an enlarged view of part B in FIG. 2 . 2 is a cross-sectional view showing the cushion body of FIG. 1 in a state where a load is input to a first bag body. FIG. FIG. 11 is a cross-sectional view showing a cushion body according to a second embodiment of the present invention in a state where no load is input. FIG. 11 is a cross-sectional view showing a cushion body according to a third embodiment of the present invention in a state where no load is input. FIG. 2 is a cross-sectional view showing an example of a seat pad that can include a cushion body according to any embodiment of the present invention. A cross-sectional view showing another example of a seat pad that can be provided with a cushion body according to any embodiment of the present invention. 1 is a diagram illustrating a method for manufacturing a cushion body according to an embodiment of the present invention, which can be used to manufacture a cushion body according to any embodiment of the present invention. 10 is a diagram for explaining a method for manufacturing the cushion body according to the embodiment of FIG. 9 . FIG. 2 is a perspective view showing a portion of an example of a porous structure that may be provided in a cushion body according to any embodiment of the present invention. 12 is a view taken along the arrow A in FIG. 11 showing the porous structure of FIG. 11 as viewed from the direction of the arrow A. FIG. FIG. 12 is a perspective view showing a cell partition of the porous structure of FIG. 11 . FIG. 14 corresponds to FIG. 13 and is a diagram for explaining a modified example of the cell partition portion. FIG. 11 is a plan view showing a portion of another example of a porous structure that can be provided in a cushion body according to any embodiment of the present invention. 16(a) is a perspective view showing the bone portion of the porous structure of FIG. 15 when no external force is applied, and FIG. 16(b) is a perspective view showing the bone portion of FIG. 15(a) when an external force is applied.

The cushion body and the method for manufacturing the cushion body of the present invention can be used for cushion bodies for any purpose, but are suitable for use in, for example, any vehicle seat and any seat pad (vehicle seat pad), and are particularly suitable for use in vehicle seats and vehicle seat pads.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a cushion body and a method for manufacturing a cushion body according to the present invention will be described by way of example with reference to the drawings.
In each drawing, the same components are denoted by the same reference numerals.

[Cushion body]
Hereinafter, cushion bodies 5 according to various embodiments of the present invention will be described with reference to FIGS. 1 to 6. FIG.
1 to 4 are diagrams for explaining a cushion body 5 according to a first embodiment of the present invention. FIG. 1 is a perspective view showing the cushion body 5 according to the first embodiment of the present invention in a state where no load is input. FIG. 2 is a cross-sectional view showing the cushion body 5 of FIG. 1 in a state where no load is input. FIG. 3 is an enlarged view showing a portion B of FIG. 2. FIG. 4 is a cross-sectional view showing the cushion body 5 of FIG. 1 in a state where a load is input to a first bag body 6 described below.
As shown in FIGS. 1 to 3, the cushion body 5 of this embodiment includes a porous structure 1 (FIGS. 2 to 3), a first bag body 6, a second bag body 7, and an orifice partition body 8.

The porous structure 1 (FIGS. 2 and 3) has a large number of cell holes and is made of flexible resin or rubber.
Here, "flexible resin" refers to a resin that can be deformed when an external force is applied, and for example, an elastomer-based resin is preferable, and polyurethane is more preferable. Examples of rubber include natural rubber and synthetic rubber. Since the porous structure 1 is made of flexible resin or rubber, it can be compressed and restored in response to the application and release of an external force from a user, and therefore can have cushioning properties.
As will be described later with reference to Figures 9 and 10, the porous structure 1 is preferably manufactured using a 3D printer, but it may also be a conventional porous structure (foam, such as urethane foam) manufactured through a process of foaming by chemical reaction.
A suitable cell structure of the porous structure 1 will be described in detail later with reference to FIGS.

The first bag 6 defines a first space 61 therein (FIGS. 2 to 3). The first bag 6 contains the porous structure 1 therein and is filled with a viscous fluid F.
As shown in FIG. 2, when no load is being input to the first bag body 6, it is preferable that the first bag body 6 is in a substantially completely inflated state.
The viscous fluid F may be any viscous fluid, but is preferably, for example, a gas such as the atmosphere (air), or a liquid such as water or ethylene glycol. The viscous fluid F is preferably a fluid having a higher viscosity than the atmosphere. A liquid is preferably, because it has a higher viscosity than a gas. Ethylene glycol is more preferably, than water, because it is less likely to freeze even in cold climates such as winter.
The first bag 6 is made of a material that is impermeable to the viscous fluid F. The first bag 6 has one or more openings 62 (only one in this example), and the openings 62 are continuous with an orifice 81 of an orifice partition 8, which will be described later. The viscous fluid F filled inside the first bag 6 can flow out through the openings 62 to an orifice 81 of an orifice partition 8, which will be described later, but cannot leak out of the first bag 6 from any other places.
As shown in FIG. 4, the first bag body 6 is configured to be flexible (i.e., capable of being deformed when an external force is applied thereto).
The material constituting the first bag body 6 may be non-stretchable or may be stretchable.
The first bag 6 is preferably made of flexible resin or rubber, and more preferably made of the same material (composition) as the porous structure 1. However, the first bag 6 may be made of a material (composition) different from that of the porous structure 1. The first bag 6 may also be made of a material other than resin or rubber.

The second bag body 7 defines a second space 71 therein (FIG. 2).
As shown in Fig. 2, it is preferable that the second bag body 7 is not completely inflated when no load is being input to the first bag body 6. When no load is being input to the first bag body 6, the second bag body 7 may be inflated to an arbitrary degree less than completely inflated, with the second space 71 substantially present inside and filled with the viscous fluid F, as shown in Fig. 2, or, although not shown, may be completely collapsed and substantially no second space 71 (and therefore no viscous fluid F) is present inside.
The second bag 7 is made of a material that is impermeable to the viscous fluid F. The second bag 7 has one or more openings 72 (only one in this example), and the opening 72 is continuous with an orifice 81 of an orifice partition 8 described later. The viscous fluid F that can enter the inside of the second bag 7 can flow out to an orifice 81 of an orifice partition 8 described later through the opening 72, but cannot leak out to the outside of the second bag 7 from any other place.
As shown in Figs. 2 and 4, the second bag body 7 is configured to be flexible (i.e., capable of being deformed when an external force is applied thereto).
The material constituting the second bag body 7 may be non-stretchable or may be stretchable.
The second bag 7 is preferably made of flexible resin or rubber, and more preferably made of the same material as the porous structure 1. However, the second bag 7 may be made of a material (composition) different from that of the porous structure 1. The second bag 7 may also be made of a material other than resin or rubber.

The orifice partition 8 defines an orifice 81. The orifice 81 communicates between the first space 61 and the second space 71. In other words, the orifice 81 communicates between the opening 62 of the first bag 6 and the opening 72 of the second bag 7.
The flow passage area of the orifice 81 is smaller than the flow passage area of the first space 61 of the first bag body 6 in a state where no load is input to the first bag body 6 (FIG. 2).
Here, the "flow passage area of the orifice 81" and the "flow passage area of the first space 61" are each measured parallel to the flow passage cross-sectional direction of the orifice 81 (a direction perpendicular to the extension direction of the orifice 81).
The orifice partition 8 is preferably made of a flexible resin or rubber, and more preferably made of the same material as the porous structure 1. However, the orifice partition 8 may be made of a material (composition) different from that of the porous structure 1. The orifice partition 8 may also be made of a material other than resin or rubber.

The first bag body 6, the second bag body 7, and the orifice partition body 8 are preferably manufactured using a 3D printer, as described later with reference to Figures 9 and 10, but may also be manufactured by other methods.

The effects of the cushion body 5 of the first embodiment configured as described above will be described.
First, when a load from the user is input to the first bag body 6 (FIG. 4), the porous structure 1 is gradually compressed and deformed, and the first bag body 6 is gradually crushed, and the first space 61 gradually shrinks, and accordingly, the viscous fluid F inside the first bag body 6 flows out into the second bag body 7 through the orifice 81. As the viscous fluid F gradually flows into the second bag body 7, the second space 71 gradually expands, and the second bag body 7 gradually swells.
Thereafter, when the load from the user is released from the first bag body 6, the porous structure 1 gradually undergoes restoration deformation, and the first bag body 6 gradually expands, and thus the first space 61 gradually expands, and accordingly, the viscous fluid F inside the second bag body 7 is drawn into the inside of the first bag body 7 through the orifice 81. As the viscous fluid F gradually flows into the inside of the first bag body 6, the first space 61 gradually expands, and the first bag body 6 gradually expands, and then it is restored to almost its original state ( FIG. 2 ).
Thereafter, the above-mentioned operation is repeated every time the user inputs and releases a load.
According to the cushion body 5 of this embodiment, the cushion body 5 includes a porous structure 1 made of flexible resin or rubber and a first bag body 6 that defines a first space 61 therein. The first bag body 6 contains the porous structure 1 and is filled with a viscous fluid F. When vibration is input to the first bag body 6, the porous structure 1 and the viscous fluid F interact with each other to obtain dynamic characteristics (specifically, vibration damping characteristics (particularly, viscous damping characteristics)) different from the dynamic characteristics obtained from the porous structure alone. Therefore, it is possible to provide a cushion body 5 having dynamic characteristics that have been difficult to obtain in the past. This is particularly suitable when the cushion body 5 is used in a seat pad (a vehicle seat pad, for example, a vehicle seat pad) to which vibration is input during use, as will be described later with reference to, for example, FIGS. 7 to 8. The higher the viscosity of the viscous fluid F, the higher the vibration damping characteristics. However, even if the viscous fluid F is air, according to the configuration of this embodiment, it is possible to obtain dynamic characteristics different from the dynamic characteristics obtained from the porous structure alone due to the interaction between the first bag body 6, the porous structure 1, and the viscous fluid F accompanying the compression and restoration deformation of the porous structure 1 that occurs when vibration is input to the first bag body 6.
Moreover, according to the cushion body 5 of this embodiment, the cushion body 5 further includes the second bag body 7 that defines the second space 71 therein, and the orifice partition body 8 that defines the orifice 81 that communicates between the first space 61 and the second space 71. Therefore, when vibration is input to the first bag body 6, the viscous fluid F1 moves between the first space 61 and the second space 71 through the orifice 81 as a load is input to the first bag body 6 and the load is released, and the fluid resistance generated thereby makes it easier to obtain dynamic characteristics different from those obtained only from the porous structure. The smaller the flow path area of the orifice 81, the higher the vibration damping characteristics.

It is to be noted that a plurality of orifice partitions 8 may be connected to the first bag 6, and each of the orifice partitions 8 may be connected to a separate second bag 7. In this case, the first bag 6 has a plurality of openings 62, each of which is continuous with an orifice 81 of a separate orifice partition 8, and each of the orifices 81 is continuous with an opening 72 of a separate second bag 7. Each of the second bags 7 has only one opening 72. Each of the orifices 81 communicates between the first space 61 and the corresponding second space 71.
Alternatively, a plurality of orifice partitions 8 may be connected to the first bag 6, and each of the orifice partitions 8 may be connected to the same second bag 7. In this case, the first bag 6 has a plurality of openings 62, and each opening 62 is continuous with an orifice 81 of a different orifice partition 8, and each orifice 81 is continuous with a different opening 72 of the same second bag 7. The second bag 7 has a plurality of openings 72. And each orifice 81 communicates between the first space 61 and the second space 71.

1 to 4, it is preferable that the first bag 6 is at least partially configured integrally with the porous structure 1, or configured separately from the porous structure 1 and bonded to the porous structure 1. This allows the first bag 6 to deform so as to more closely follow the compression and restoration deformation of the porous structure 1 when vibration is input to the first bag 6, making it easier to obtain dynamic characteristics different from those obtained from the porous structure alone.
However, in this embodiment, the first bag 6 may be configured as a whole separately from the porous structure 1 and may be in a non-adhered state to the porous structure 1. Even in this case, according to this embodiment, it is possible to obtain dynamic characteristics different from the dynamic characteristics obtained from the porous structure alone due to the interaction between the first bag 6, the porous structure 1, and the viscous fluid F accompanying the compression and restoration deformation of the porous structure 1 that occurs when vibration is input to the first bag 6, and the movement of the viscous fluid F1 between the first space 61 and the second space 71 via the orifice 81.

The flow area of the orifice 81 is preferably 0.3 times or less, more preferably 0.1 times or less, and even more preferably 0.05 times or less, of the flow area of the first space 61 of the first bag body 6 when no load is applied to the first bag body 6 (Figure 2). This allows the vibration damping characteristics to be improved, and makes it easier to obtain dynamic characteristics different from those obtained from the porous structure alone.

In the example of Figs. 1 to 4, the orifice 81 forms a passage, i.e., extends with a certain extension length. The orifice partition 8 is configured in a tubular shape. More specifically, in this example, the extension length of the orifice 81 is longer than the diameter of the orifice 81. This allows the vibration damping characteristics to be improved, and dynamic characteristics different from those obtained only from the porous structure are more easily obtained. In addition, this allows the second bag 7 to be disposed farther away from the first bag 6, so that, for example, the second bag 7 can be easily disposed in a position that is difficult to touch the user's body or difficult to see from the user.
However, this configuration is not essential. For example, the extension length of the orifice 81 may be equal to or less than the diameter of the orifice 81.

In the example shown in FIGS. 1 to 4, the first bag 6, the porous structure 1, and the second bag 7 each have a substantially rectangular parallelepiped shape, but each of these may have any shape.
However, when no load is input to the first bag body 6 (Figure 2), it is preferable that the shape and size of the porous structure 1 are approximately the same as those of the first space 61 of the first bag body 6, that is, it is preferable that the entire outer edge (outer contour) of the porous structure 1 is adapted to (i.e. fits) the inner surface of the first bag body 6.
In addition, in the examples shown in Figures 1 to 4, the orifice partition 8 has a circular tubular shape, but the orifice partition 8 may have any tubular shape other than a circular tubular shape, or may have any shape other than a tubular shape.

Next, a cushion body 5 according to a second embodiment of the present invention will be described, focusing on the differences from the first embodiment (FIGS. 1 to 4). FIG 5 is a cross-sectional view showing the cushion body 5 according to the second embodiment of the present invention in a state where no load is input.
The cushion body 5 of this embodiment is similar to the first embodiment (Figures 1 to 4) in that it comprises a porous structure 1 and a first bag body 6, and the inside of the first bag body 6 contains the porous structure 1 and is filled with a viscous fluid F. However, it differs from the first embodiment in that it does not comprise a second bag body 7 and an orifice partition body 8.
The first bag 6 of the present embodiment differs from the first bag 6 of the first embodiment in that it does not have any openings. That is, in the present embodiment, the viscous fluid F is sealed inside the first bag 6 and is prevented from flowing out of the first bag 6.
Other than that, the porous structure 1, the first bag body 6, and the viscous fluid F are similar to those described in the first embodiment.

According to the cushion body 5 of the second embodiment configured as described above, the cushion body 5 includes a porous structure 1 made of flexible resin or rubber and a first bag body 6 that defines a first space 61 therein. The first bag body 6 contains the porous structure 1 and is filled with a viscous fluid F. When vibration is input to the first bag body 6, the porous structure 1 and the viscous fluid F interact with each other due to the compression and restoration deformation of the porous structure 1, which occurs when vibration is input to the first bag body 6. This makes it possible to obtain dynamic characteristics (specifically, vibration damping characteristics (particularly viscous damping characteristics)) different from the dynamic characteristics obtained from the porous structure alone. Therefore, it is possible to provide a cushion body 5 with dynamic characteristics that were difficult to obtain in the past. This is particularly suitable when the cushion body 5 is used in a seat pad (a vehicle seat pad, for example, a vehicle seat pad) to which vibration is input during use, as will be described later with reference to Figures 7 to 8. The higher the viscosity of the viscous fluid F, the higher the vibration damping characteristics. However, even if the viscous fluid F is air, the configuration of this embodiment makes it possible to obtain dynamic characteristics different from those obtained from the porous structure alone, due to the interaction between the first bag body 6, the porous structure 1, and the viscous fluid F that accompanies the compression and restoration deformation of the porous structure 1 that occurs when vibration is input to the first bag body 6.

5, the first bag 6 may be configured as a separate entity from the porous structure 1 and may be in a non-adhered state to the porous structure 1. Even in this case, according to this embodiment, it is possible to obtain dynamic characteristics different from the dynamic characteristics obtained from the porous structure alone due to the interaction between the first bag 6, the porous structure 1, and the viscous fluid F accompanying the compression and restoration deformation of the porous structure 1 that occurs when vibration is input to the first bag 6.
Alternatively, in this embodiment, the first bag body 6 may be at least partially configured as one piece with the porous structure 1, or may be configured as a separate body from the porous structure 1 and bonded to the porous structure 1. In this case, when vibration is input to the first bag body 6, the first bag body 6 can deform so as to more closely follow the compression and restoration deformation of the porous structure 1, making it easier to obtain dynamic characteristics different from the dynamic characteristics obtained from the porous structure alone.

Next, a cushion body 5 according to a third embodiment of the present invention will be described, focusing on the differences from the first embodiment (FIGS. 1 to 4) and the second embodiment (FIG. 5). Fig. 6 is a cross-sectional view showing the cushion body 5 according to the third embodiment of the present invention in a state where no load is input.
The cushion body 5 according to this embodiment differs from the first or second embodiment described above in that, in addition to the porous structure 1 (hereinafter also referred to as the "first porous structure 1b") contained inside the first bag body 6 in the cushion body 5 of the first or second embodiment described above, another porous structure 1 (hereinafter also referred to as the "second porous structure 1a") is arranged so as to surround the periphery of the first bag body 6. That is, the first bag body 6 (and the first porous structure 1b and the viscous fluid F therein) are located inside a space partitioned on the inner periphery side of the second porous structure 1a. The other configurations are the same as those of the first or second embodiment.
A load from the user is input from above the second porous structure 1a. At that time, the load applied to the second porous structure 1a causes a load to be applied from the second porous structure 1a to the first bag body 6, and the first bag body 6 and the porous structure 1 are deformed in the same manner as in the first or second embodiment.
According to the third embodiment, in addition to the effects described above in the first or second embodiment, an interaction occurs between the second porous structure 1a and the first bag body 6 due to the compression and restoration deformation of the second porous structure 1a, making it easier to obtain dynamic characteristics different from the dynamic characteristics obtained from the porous structure alone.

In the embodiment of Fig. 6, it is preferable that the first bag 6 is at least partially integral with the second porous structure 1a, or is formed separately from the second porous structure 1a and bonded to the second porous structure 1a. This allows the first bag 6 to deform so as to more closely follow the compression and restoration deformation of the second porous structure 1a when vibration is input to the second porous structure 1a, making it easier to obtain dynamic characteristics different from those obtained from the porous structure alone.
However, in this embodiment, the first bag body 6 may be configured as a separate body from the second porous structure 1a and may be in a non-adhered state to the second porous structure 1a as a whole. Even in this case, according to this embodiment, it is possible to obtain dynamic characteristics different from those obtained from the porous structure alone due to the interaction between the first bag body 6, the first porous structure 1b, and the viscous fluid F accompanying the compression and restoration deformation of the first porous structure 1b that occurs when vibration is input to the first bag body 6, and the interaction between the second porous structure 1a and the first bag body 6 accompanying the compression and restoration deformation of the second porous structure 1a, etc.

As will be described later with reference to Figures 9 to 10, it is preferable that the cushion body 5 according to each embodiment described in this specification has portions other than the viscous fluid F formed by a 3D printer.
By using a 3D printer to manufacture the parts of the cushion body 5 other than the viscous fluid F, manufacturing is simplified and a desired configuration can be obtained. Furthermore, with future technological advances in 3D printers, it is expected that manufacturing using a 3D printer will be possible in the future in a shorter time and at a lower cost. Furthermore, by using a 3D printer to manufacture the parts of the cushion body 5 other than the viscous fluid F, a configuration of the cushion body 5 that meets various required characteristics can be easily and desired.
When the portions of the cushion body 5 other than the viscous fluid F are manufactured using a 3D printer, flexible resin or rubber is suitable as a material for forming the portions of the cushion body 5 other than the viscous fluid F, and for example, a resin made of photocurable polyurethane (particularly ultraviolet-curable polyurethane) can be used. As the photocurable polyurethane (particularly ultraviolet-curable polyurethane), a resin made of urethane acrylate or urethane methacrylate can be used. Examples of such resins include those described in US Pat. No. 4,337,130.

[Seat pad with cushion body]
As described above, the cushion body 5 according to each embodiment of the present invention can be used in a seat pad (a seat pad for vehicles, particularly a seat pad for a car).
Hereinafter, with reference to FIGS. 7 and 8, an example of a seat pad 302 that may include a cushion body 5 according to any embodiment of the present invention will be described.
Fig. 7 is a cross-sectional view that shows a schematic example of a seat pad 302 (vehicle seat pad) that can include the cushion body 5 according to various embodiments of the present invention. Fig. 8 is a cross-sectional view that shows a schematic example of another seat pad 302 (vehicle seat pad) that can include the cushion body 5 according to various embodiments of the present invention.
In this specification, the directions of "upper", "lower", "left", "right", "front", and "rear" as seen from a seated person seated on the seat pad 302 are simply referred to as "upper", "lower", "left", "right", "front", "rear", etc. Figures 7 and 8 each show a cross section of the seat pad 302 cut in the left-right direction.
In each of the examples of Figures 7 and 8, the seat pad 302 may be configured as a cushion pad for a seated person to sit on, or may be configured as a back pad for supporting the back of a seated person.
The seat pad 302 has a main pad portion 311 and a pair of side pad portions 312 located on both the left and right sides of the main pad portion 311. When the seat pad 302 is configured as a cushion pad, the main pad portion 311 is configured to support the buttocks and thighs of a seated person from below. When the seat pad 302 is configured as a back pad, the main pad portion 311 is configured to support the back of the seated person from the rear.
Moreover, the surface (front surface) FS of the seat pad 302 facing the occupant is the upper surface in the case of a cushion pad, and the front surface in the case of a back pad. The back surface BS of the seat pad 302 is the surface opposite to the surface FS of the seat pad 302 facing the occupant, and is the lower surface in the case of a cushion pad, and is the rear surface in the case of a back pad. The side surface SS of the seat pad 302 is the surface between the surface FS of the seat pad 302 facing the occupant and the back surface BS, and is any one of the front surface, rear surface, left surface, or right surface in the case of a cushion pad, and is any one of the lower surface, upper surface, left surface, or right surface in the case of a back pad.
In the example of FIG. 7, the seat pad 302 includes a cushion body 5 according to any embodiment of the present invention and a main body 314. The main body 314 has a recess 313 for accommodating a part or all of the cushion body 5, and is made of a porous structure (foam) manufactured through a process of foaming by chemical reaction in, for example, mold molding or slab molding. It is preferable that the recess 313 accommodates at least a part or all of the first bag 6 (and thus the porous structure 1 and the viscous fluid F accommodated inside the first bag 6) of the cushion body 5. In the example of FIG. 7, the recess 313 and the part of the cushion body 5 accommodated inside the recess 313 may each have any shape as long as they are shaped to fit each other, and may each have an approximately rectangular parallelepiped shape as in the example of FIG. 7.
As in the example of Figure 7, by the cushion body 5 constituting only a part of the seat pad 302, the size of the cushion body 5 can be made smaller than if the cushion body 5 constituted the entire seat pad 302 (Figure 8), and ultimately the cushion body 5 can be manufactured using a relatively small 3D printer.
7, the cushion body 5 may constitute any part of the seat pad 302. It is preferable that the cushion body 5 constitutes at least a part of the main pad portion 311 of the seat pad 302.
In the example of Fig. 8, the seat pad 302 is composed only of the cushion body 5 according to any embodiment of the present invention. In the example of Fig. 8, a part or the whole of the cushion body 5 (in the example of Fig. 8, the first bag body 6 and the porous structure 1) forms the shape of a seat pad.

[Method of manufacturing cushion body]
Next, a method for manufacturing the cushion body of the present invention will be described with reference to FIGS. 9 to 10. The method described below is a method for manufacturing the parts of the cushion body 5 other than the viscous fluid F using a 3D printer, and can be suitably used to manufacture the cushion body 5 of any embodiment described in this specification. FIG. 9 shows the manner in which the cushion body 5 according to the first embodiment (FIGS. 1 to 4) described above is manufactured. In the example of FIG. 9, the parts of the cushion body 5 other than the viscous fluid F (the first bag body 6, the porous structure 1, and in some cases, the second bag body 7, the orifice partition body 8, etc.) are molded into a plurality of parts 9a to 9c using a 3D printer, and then the molded parts 9a to 9c are fixed to each other and the inside of the first bag body 6 is filled with the viscous fluid F.

First, using a computer, three-dimensional shape data (e.g., three-dimensional CAD data) representing the three-dimensional shape of each of the parts 9a to 9c when the parts other than the viscous fluid F in the cushion body 5 (the first bag body 6, the porous structure 1, and optionally the second bag body 7, the orifice partition body 8, etc.) are divided into any number of parts 9a to 9c is created in advance (three-dimensional shape data creation step).
That is, in the three-dimensional shape data creating step, separate three-dimensional shape data is created for each of the parts 9a to 9c.

Next, using a computer, each of the three-dimensional shape data is converted into 3D printing data 500 (500a to 500c) (FIG. 9A, 3D printing data conversion step).
The 3D printing data 500 is read into the control unit 410 of the 3D printer 400 when the modeling unit 420 of the 3D printer 400 performs modeling, and the control unit 410 is configured to cause the modeling unit 420 to model an object having a shape represented by the above three-dimensional shape data. The 3D printing data 500 includes, for example, slice data representing the two-dimensional shape of each layer of the object having a shape represented by the above three-dimensional shape data.

Next, the above-mentioned multiple parts 9a to 9c of the cushion body 5 are modeled for each of the parts 9a to 9c by the 3D printer 400 (Figure 9(b), modeling step).
FIG. 9B shows the part 9a being molded.
The 3D printer 400 may perform modeling using any modeling method, such as a stereolithography method, a powder sintering lamination method, a fused deposition modeling (FDM) method, an inkjet method, etc. From the viewpoint of productivity, the stereolithography method is preferable. Fig. 9 shows a state in which modeling is performed using the stereolithography method.
The 3D printer 400 includes, for example, a control unit 410 configured by a CPU or the like, a modeling unit 420 that performs modeling under the control of the control unit 410, a support table 430 for placing the object to be modeled (i.e., the above-mentioned part), and a container 440 that contains the liquid resin LR, the support table 430, and the object. When the optical modeling method is used as in this example, the modeling unit 420 has a laser irradiator 421 configured to irradiate ultraviolet laser light LL. The container 440 is filled with the liquid resin LR. When the ultraviolet laser light LL irradiated from the laser irradiator 421 hits the liquid resin LR, it hardens and becomes a flexible resin.
In the 3D printer 400 configured in this manner, the control unit 410 first reads the 3D modeling data 500, and then controls the modeling unit 420 to irradiate ultraviolet laser light LL based on the three-dimensional shape contained in the read 3D modeling data 500, thereby sequentially modeling each layer.
After the modeling by the 3D printer 400 is completed, the modeled object (parts 9a to 9c) is removed from the container 440. At this time, if any liquid resin LR remains inside the parts 9a to 9c, the liquid resin LR is removed. As a result, the above-mentioned multiple parts 9a to 9c are obtained (FIG. 9C).

Thereafter, the obtained plurality of parts 9a to 9c are fixed to each other, and the inside of the first bag 6 is filled with a viscous fluid F (FIG. 10, fixing and filling step).
In the bonding and filling step, bonding the plurality of parts 9a to 9c to each other and filling with the viscous fluid F may be performed in any order. For example, after some (a plurality of) parts (e.g., parts 9a and 9c) of the plurality of parts 9a to 9c are bonded to each other, the inside of the first bag body 6 may be filled with the viscous fluid F, and then the some of the parts (e.g., parts 9a and 9c) may be bonded to the remaining part (e.g., part 9b).
The multiple parts may be bonded to each other by, for example, heat-sealing the multiple parts in an oven before the multiple parts are completely cured, as shown in Fig. 10. In this case, adhesive is not essential, but adhesive may be used between the multiple parts. Heating in an oven can strengthen the bond between the multiple parts and also strengthen the bond between the layers constituting each part, thereby reducing anisotropy and improving the cushioning properties of the cushion body 5.
In addition, when the multiple parts 9a to 9c obtained in the modeling step are made of rubber (unvulcanized rubber), the multiple parts may be bonded to each other by vulcanizing the multiple parts in a bonded state.
Alternatively, the multiple components may be bonded together only by adhesion using an adhesive.

After the bonding and filling steps, the cushion body 5 is finally obtained.

In the example shown in Figures 9 and 10, the portion of the cushion body 5 other than the viscous fluid F is divided into a part 9a consisting of a portion of the first bag body 6 (specifically, a portion other than one of the walls) 6a and the porous structure 1, a part 9b consisting of the remaining portion of the first bag body 6 (specifically, the above-mentioned one of the walls) 6b, and a part 9c consisting of the second bag body 7 and the orifice partition body 8. For each of these parts, a three-dimensional shape data creation step, a 3D printing data conversion step, and a printing step are performed.
By dividing the first bag 6 into a part 9a consisting of a part (specifically, a part other than one wall) 6a and the porous structure 1, and a part 9b consisting of the remaining part (specifically, the one wall) 6b of the first bag 6, the liquid resin LR can be easily removed from the part 9a after the completion of the modeling in the modeling step, and the fixing and filling step can be easily performed by filling the part 6a of the first bag 6 in the part 9a with the viscous fluid F and then fixing the part 9a and the part 9b. Dividing the part 9a and the part 9b and performing the three-dimensional shape data creation step, the 3D modeling data conversion step, and the modeling step can be suitably adopted not only when manufacturing the cushion body 5 according to the first embodiment (FIGS. 1 to 4) described above, but also when manufacturing the cushion body 5 according to any embodiment of this specification.
In addition, by dividing the part 9a into a part 9a consisting of a portion 6a (specifically, a part other than one wall) of the first bag body 6 and the porous structure 1, and a part 9c consisting of the second bag body 7 and the orifice partition body 8, it becomes easier to remove the liquid resin LR from part 9c after molding in the molding step is completed.
Although not shown in the drawings, the same effect can be obtained even if the three-dimensional shape data creation step, the 3D printing data conversion step, and the printing step are performed with the orifice partition 8 as part of the part 9a rather than as part 9c.

Although the method for manufacturing the cushion body of the present invention has been described above by way of example, the cushion body 5 according to any embodiment of the present invention may be manufactured by a method different from the above-described method for manufacturing the cushion body.
For example, only a portion of the cushion body 5 other than the viscous fluid F may be manufactured using a 3D printer, and the other portions may be manufactured by a method that does not use a 3D printer.

[Porous Structure]
Next, the above-mentioned porous structure 1 will be described in detail with reference to Fig. 11 to Fig. 16. The porous structure 1 described below can be used for the cushion body 5 according to any embodiment described in this specification.
11 to 14, in order to facilitate understanding of the orientation of the porous structure 1, the orientation of an XYZ orthogonal coordinate system fixed to the porous structure 1 is shown.

In Figures 11 and 12, a portion of the porous structure 1 having an approximately rectangular parallelepiped outer shape is viewed from different angles. Figure 11 is a perspective view showing that portion of the porous structure 1. Figure 12 is a view seen from the direction of arrow A (Y direction) showing that portion of the porous structure 1 in Figure 11.

The porous structure 1 is shaped by a 3D printer. By manufacturing the porous structure 1 using a 3D printer, manufacturing is easier than in the conventional case where a foaming process is performed by chemical reaction, and the desired configuration can be obtained. Furthermore, with future technological advances in 3D printers, it is expected that in the future, manufacturing using 3D printers will be possible in a shorter time and at a lower cost. Furthermore, by manufacturing the porous structure 1 using a 3D printer, the configuration of the porous structure 1 that meets various required characteristics can be easily realized as desired.

As described above, the porous structure 1 is made of flexible resin or rubber.
From the viewpoint of ease of manufacturing using a 3D printer, it is more preferable for the porous structure 1 to be made of a flexible resin than of rubber.
From the viewpoint of ease of manufacturing using a 3D printer, it is preferable that the entire porous structure 1 is made of a material having the same composition, but the porous structure 1 may be made of materials having different compositions depending on the portion.

As described above, the porous structure 1 is formed by a 3D printer. The porous structure 1 is configured as a single unit in its entirety.
The porous structure 1 is made of flexible resin or rubber. More specifically, the porous structure 1 includes a skeleton 2 that forms the skeleton of the porous structure 1. The skeleton 2 defines a large number of cell holes C. The skeleton 2 is present throughout almost the entire porous structure 1, and is made of flexible resin or rubber. In this example, the portions of the porous structure 1 other than the skeleton 2 are voids, in other words, the porous structure 1 is made of only the skeleton 2.

11 to 13, the skeleton 2 of the porous structure 1 is composed of a plurality of bones 2B and a plurality of connecting portions 2J, and the entire skeleton 2 is integrally constructed. In this example, each bone 2B is formed in a columnar shape and extends linearly. Each connecting portion 2J connects end portions 2Be of a plurality of (e.g., four) bone portions 2B extending in different directions to each other at locations where these end portions 2Be are adjacent to each other in the extension direction.
11 to 13, the skeleton line O of the skeleton 2 is shown by a dashed line in a part of the porous structure 1. The skeleton line O of the skeleton 2 is composed of the skeleton line O of each bone portion 2B and the skeleton line O of each joint portion 2J. The skeleton line O of the bone portion 2B is the central axis of the bone portion 2B. The skeleton line O of the joint portion 2J is an extension line portion formed by smoothly extending the central axes of each bone portion 2B joined to the joint portion 2J into the joint portion 2J and connecting them to each other. The central axis of the bone portion 2B is a line connecting the centers of gravity of the shape of the bone portion 2B in a cross section perpendicular to the extension direction of the bone portion 2B at each point in the extension direction of the bone portion 2B.
The extending direction of the bone portion 2B is the extending direction of a skeleton line O of the bone portion 2B (a portion of the skeleton line O that corresponds to the bone portion 2B; the same applies below).
Since the porous structure 1 has the skeleton 2 over almost the entire surface thereof, it is possible for it to be compressed and restored in response to the application and release of an external force while ensuring breathability, and therefore has good characteristics as a cushioning material. In addition, the structure of the porous structure 1 is simple, making it easy to model using a 3D printer.
In addition, some or all of the bone parts 2B among the bone parts 2B constituting the skeleton 2 may extend while being curved. In this case, by having some or all of the bone parts 2B bent, it is possible to prevent a sudden change in shape of the bone parts 2B and therefore the porous structure 1 when a load is input, and to suppress local buckling.

In this example, each bone 2B constituting the skeletal part 2 has approximately the same shape and length. However, this is not limited to this example, and the shape and/or length of each bone 2B constituting the skeletal part 2 do not have to be the same, and for example, the shape and/or length of some bones 2B may be different from the other bones 2B. In this case, by making the shape and/or length of a specific part of the bones 2B of the skeletal part 2 different from the other parts, it is possible to intentionally obtain different mechanical properties.

In this example, the width W0 (FIG. 11) and cross-sectional area of each bone portion 2B are constant over the entire length of the bone portion 2B (i.e., uniform along the extension direction of the bone portion 2B).
Here, the cross-sectional area of the bone portion 2B refers to the cross-sectional area of a cross section of the bone portion 2B perpendicular to the skeletal line O. Moreover, the width W0 (FIG. 11) of the bone portion 2B refers to the maximum width in the cross section when measured along the cross section perpendicular to the skeletal line O of the bone portion 2B.
However, in each example described in this specification, the width W0 and/or cross-sectional area of some or all of the bone parts 2B constituting the skeletal part 2 may be non-uniform along the extension direction of the bone part 2B. For example, the width W0 of some or all of the bone parts 2B constituting the skeletal part 2 may be gradually increased or decreased toward both ends in the extension direction of the bone part 2B in a portion including the end parts 2Be on both sides in the extension direction of the bone part 2B. Also, the cross-sectional area of some or all of the bone parts 2B constituting the skeletal part 2 may be gradually increased or decreased toward both ends in the extension direction of the bone part 2B in a portion including the end parts 2Be on both sides in the extension direction of the bone part 2B. Also, in this specification, "gradual change (increase or decrease)" refers to a smooth change (increase or decrease) without becoming constant halfway.

In each example described in this specification, from the viewpoint of simplifying the structure of the skeleton 2 and thus facilitating the manufacture of the porous structure 1 by a 3D printer, the width W0 (FIG. 11) of the bone portion 2B is preferably 0.05 mm or more, and more preferably 0.10 mm or more. When the width W0 is 0.05 mm or more, it is possible to mold with the resolution of a high-performance 3D printer, and when it is 0.10 mm or more, it is possible to mold with the resolution of not only a high-performance 3D printer but also a general-purpose 3D printer.
On the other hand, from the viewpoint of improving the accuracy of the outer edge (outer contour) shape of the skeleton portion 2, from the viewpoint of reducing the gaps (spacing) between the cell holes C, and from the viewpoint of improving the characteristics as a cushioning material, it is preferable that the width W0 of the bone portion 2B be 2.0 mm or less.
It is preferable that each of the bone parts 2B constituting the skeletal part 2 satisfy this configuration, but it is also acceptable for only some of the bone parts 2B constituting the skeletal part 2 to satisfy this configuration, and even in this case, a similar effect can be obtained, although to varying degrees.

In this example, each of the bones 2B constituting the skeleton 2 is columnar, and each has a circular (perfect circular) cross-sectional shape.
This simplifies the structure of the skeleton 2, making it easier to model using a 3D printer. In addition, it is easy to reproduce the mechanical properties of general polyurethane foam manufactured through a process of foaming by chemical reaction. This improves the properties of the porous structure 1 as a cushioning material. Furthermore, by forming the bones 2B in a columnar shape in this way, the durability of the skeleton 2 can be improved compared to the case where the bones 2B are replaced with thin membrane-like parts.
The cross-sectional shape of each bone portion 2B is the shape of a cross section perpendicular to the central axis (skeleton line O) of the bone portion 2B.
In addition, without being limited to this example, only some of the bone parts 2B among the bone parts 2B that constitute the skeletal part 2 may satisfy this configuration, and even in that case, the same effect can be obtained, although to different degrees.
For example, in each example described in this specification, the cross-sectional shape of all or some of the bones 2B constituting the skeleton 2 may be a polygon (equilateral triangle, triangle other than equilateral triangle, rectangle, etc.) or a circle other than a perfect circle (ellipse, etc.), and even in such cases, the same effect as in this example can be obtained. Furthermore, the cross-sectional shape of each bone 2B may be uniform along its extension direction, or may be non-uniform along its extension direction. Furthermore, the cross-sectional shapes of each bone 2B may differ from each other.

In each example described in this specification, it is preferable that the ratio (VB×100/VS [%)) of the volume VB occupied by the skeleton part 2 to the apparent volume VS of the skeleton part 2 is 3 to 10%. With this configuration, the reaction force generated in the skeleton part 2 when an external force is applied to the skeleton part 2, and thus the hardness of the skeleton part 2 (and thus the hardness of the porous structure 1) can be improved as a cushioning material, for example, as a seat pad (particularly a seat pad for a vehicle).
Here, the "apparent volume VS of the skeleton 2" refers to the volume of the entire internal space surrounded by the outer edge (outer contour) of the skeleton 2 (the sum of the volume occupied by the skeleton 2, the volume occupied by the membrane 3 (Figure 14) described below if provided, and the volume occupied by the voids).
When the material constituting the skeleton 2 is considered to be the same, the higher the ratio of the volume VB occupied by the skeleton 2 to the apparent volume VS of the skeleton 2, the harder the skeleton 2 (and thus the porous structure 1) will be. Also, the lower the ratio of the volume VB occupied by the skeleton 2 to the apparent volume VS of the skeleton 2, the softer the skeleton 2 (and thus the porous structure 1) will be.
From the viewpoint of improving the reaction force generated in the skeletal portion 2 when an external force is applied to the skeletal portion 2, and thus the hardness of the skeletal portion 2 (and thus the porous structure 1) as a cushioning material, for example, as a seat pad (particularly a seat pad for a vehicle), it is more preferable that the proportion of the volume VB occupied by the skeletal portion 2 in the apparent volume VS of the skeletal portion 2 be 4 to 8%.
Any method may be used to adjust the proportion of the volume VB occupied by the skeletal portion 2 in the apparent volume VS of the skeletal portion 2, but examples include a method of adjusting the thickness (cross-sectional area) of some or all of the bone portions 2B that constitute the skeletal portion 2 and/or the size (cross-sectional area) of some or all of the joint portions J that constitute the skeletal portion 2.

In each example described in this specification, the 25% hardness of the porous structure 1 is preferably 60 to 500 N, and more preferably 100 to 450 N. Here, the 25% hardness (N) of the porous structure 1 is a measured value obtained by measuring the load (N) required to compress the porous structure by 25% in an environment of 23°C and relative humidity of 50% using an Instron type compression tester. This allows the porous structure 1 to have a good hardness as a cushioning material, for example, as a seat pad (particularly a seat pad for a vehicle).

As shown in FIGS. 11 to 13, in this example, the skeleton 2 has a plurality of cell partitions 21 (the same as the number of cell holes C) that partition the cell holes C therein.
13 shows only one cell partition 21. The skeleton 2 of this example has a structure in which a large number of cell partitions 21 are aligned in each of the X, Y, and Z directions.
11 to 13, each cell partition 21 has a plurality of (14 in this example) annular portions 211. Each annular portion 211 is configured in an annular shape, and defines a flat imaginary plane V1 by the annular inner peripheral edge portion 2111. The imaginary plane V1 is a virtual plane (i.e., a virtual closed plane) defined by the inner peripheral edge portion 2111 of the annular portion 211. The multiple annular portions 211 constituting the cell partition 21 are connected to each other so that the imaginary planes V1 defined by the respective inner peripheral edge portions 2111 do not intersect with each other.
The cell hole C is defined by a plurality of annular portions 211 constituting the cell partition 21 and a plurality of imaginary surfaces V1 defined by the plurality of annular portions 211. In general terms, the annular portions 211 are portions defining the sides of the three-dimensional shape of the cell hole C, and the imaginary surfaces V1 are portions defining the constituent surfaces of the three-dimensional shape of the cell hole C.
Each annular portion 211 is composed of a plurality of bone portions 2B and a plurality of connecting portions 2J that connect the ends 2Be of the plurality of bone portions 2B to each other.
A connection portion between a pair of mutually connected annular portions 211 is composed of one bone portion 2B and a pair of connecting portions 2J on both sides thereof, which are shared by the pair of annular portions 211. In other words, each bone portion 2B and each connecting portion 2J is shared by a plurality of adjacent annular portions 211.
Each imaginary surface V1 defines a portion of one cell hole C by one surface of the imaginary surface V1 (the front surface of the imaginary surface V1), and defines a portion of another cell hole C by the other surface of the imaginary surface V1 (the back surface of the imaginary surface V1). In other words, each imaginary surface V1 defines a portion of a different cell hole C by both its front and back surfaces. In further other words, each imaginary surface V1 is shared by a pair of cell holes C adjacent to the imaginary surface V1 (i.e., a pair of cell holes C sandwiching the imaginary surface V1 therebetween).
Moreover, each annular portion 211 is shared by a pair of cell partitions 21 adjacent to the annular portion 211 (i.e., a pair of cell partitions 21 sandwiching the annular portion 211 therebetween). In other words, each annular portion 211 constitutes a part of each of the pair of cell partitions 21 adjacent to each other.
11 and 12, a part of imaginary surfaces V1 in the porous structure 1 is not covered by a membrane 3 (FIG. 14) described later and is open, i.e., forms an opening. Therefore, the cell holes C communicate with each other through the imaginary surfaces V1, and ventilation between the cell holes C is possible. This improves the ventilation of the skeleton 2 and facilitates compression and restoration deformation of the skeleton 2 in response to application and release of an external force.

As shown in FIG. 13, in this example, the skeleton line O of each cell partition 21 is in the shape of a polyhedron, and therefore each cell hole C is in the shape of a substantially polyhedron. More specifically, in the examples of FIG. 11 to FIG. 13, the skeleton line O of each cell partition 21 is in the shape of a Kelvin tetradecahedron (truncated octahedron), and therefore each cell hole C is in the shape of a substantially Kelvin tetradecahedron (truncated octahedron). A Kelvin tetradecahedron (truncated octahedron) is a polyhedron composed of six regular quadrilateral constituent faces and eight regular hexagonal constituent faces. The cell holes C constituting the skeleton 2 are arranged with regularity so as to fill the internal space surrounded by the outer edge (outer contour) of the skeleton 2 (i.e., so that the cell holes C are arranged without any unnecessary gaps, in other words, so as to reduce the gaps (spacing) between the cell holes C).
As in this example, by making the shape of the skeletal lines O of some or all (in this example, all) of the cell partition sections 21 of the skeletal section 2 a polyhedron (and thus the shape of the cell holes C of some or all (in this example, all) of the skeletal section 2), it is possible to make the gaps (spacing) between the cell holes C that constitute the skeletal section 2 smaller, and more cell holes C can be formed inside the skeletal section 2. This also improves the behavior of the compression and restoration deformation of the skeletal section 2 (and thus the porous structure 1) in response to the application and release of an external force when used as a cushioning material, for example as a seat pad (particularly a seat pad for a vehicle).
The polyhedral shape of the skeleton lines O of the cell partitions 21 (and thus the polyhedral shape of the cell holes C) is not limited to this example, and may be any shape. For example, the shape of the skeleton lines O of the cell partitions 21 (and thus the shape of the cell holes C) is preferably an approximately tetrahedron, an approximately octahedron, or an approximately dodecahedron from the viewpoint of reducing the gaps (spacing) between the cell holes C. The shape of the skeleton lines O of some or all of the cell partitions 21 of the skeleton 2 (and thus the shape of some or all of the cell holes C of the skeleton 2) may be a three-dimensional shape other than an approximately polyhedron (for example, a sphere, an ellipsoid, a cylinder, etc.). The skeleton 2 may have only one type of cell partitions 21 having the same shape of the skeleton lines O as the cell partitions 21, or may have multiple types of cell partitions 21 having different shapes of the skeleton lines O. Similarly, the skeleton 2 may have only one type of cell holes C having the same shape as the cell holes C, or may have a plurality of types of cell holes C having different shapes. When the shape of the skeleton lines O of the cell partitioning parts 21 (and thus the shape of the cell holes C) is made to be a substantial Kelvin tetradecahedron (truncated octahedron) as in this example, it is easiest to reproduce the characteristics of a cushioning material equivalent to that of a general polyurethane foam manufactured through a process of foaming by chemical reaction, compared to other shapes.

11 to 13, in this example, the multiple (14 in this example) annular portions 211 constituting the cell partition 21 each include one or more (six in this example) small annular portions 211S and one or more (eight in this example) large annular portions 211L. Each small annular portion 211S defines a flat small imaginary surface V1S by its annular inner peripheral edge 2111. Each large annular portion 211L defines a large imaginary surface V1L that is flat and has a larger area than the small imaginary surface V1S by its annular inner peripheral edge 2111. The small imaginary surface V1S and the large imaginary surface V1L are each an imaginary plane (i.e., an imaginary closed plane).
13, in this example, the large annular portion 211L has a skeleton line O that forms a regular hexagon, and accordingly, the large imaginary surface V1L also has a substantially regular hexagon. Also, in this example, the small annular portion 211S has a skeleton line O that forms a regular rectangle, and therefore, the small imaginary surface V1S also has a substantially regular rectangle. Thus, in this example, the small imaginary surface V1S and the large imaginary surface V1L differ not only in area but also in shape.
Each of the large annular portions 211L is composed of a plurality of (six in this example) bone portions 2B and a plurality of (six in this example) connecting portions 2J connecting the ends 2Be of the bone portions 2B. Each of the small annular portions 211S is composed of a plurality of (four in this example) bone portions 2B and a plurality of (four in this example) connecting portions 2J connecting the ends 2Be of the bone portions 2B.
11 to 13, the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 each form a Kelvin tetradecahedron (truncated octahedron). As described above, a Kelvin tetradecahedron (truncated octahedron) is a polyhedron composed of six regular quadrilateral constituent faces and eight regular hexagonal constituent faces. Accordingly, the cell holes C defined by each cell partition 21 also form approximately a Kelvin tetradecahedron. The skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 are connected to each other so as to fill the space. In other words, there are no gaps between the skeleton lines O of the multiple cell partitions 21.

In this way, in this example, the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 each form a polyhedron (in this example, a Kelvin tetrahedron), and accordingly, the cell holes C form an approximately polyhedron (in this example, an approximately Kelvin tetrahedron), so that it is possible to make the gaps (spacings) between the cell holes C constituting the porous structure 1 smaller, and more cell holes C can be formed inside the porous structure 1. This also makes it possible for the porous structure 1 to be better in terms of the behavior of compression and restoration deformation in response to the application and release of an external force as a cushioning material, for example, as a seat pad (particularly a seat pad for a vehicle). The gaps (spacings) between the cell holes C correspond to the fleshy parts (bone parts 2B and joint parts 2J) of the skeleton 2 that partition the cell holes C.
In addition, in this example, the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 are connected to each other so as to fill the space, so that it is possible to further reduce the gaps (intervals) between the cell holes C constituting the porous structure 1. This improves the characteristics of the porous structure as a cushioning material.

The polyhedron formed by the skeleton lines O of the cell partitioning portion 21 (and thus the approximate polyhedron formed by the cell holes C) is not limited to the examples shown in the figures, and any desired shape is possible.
For example, it is preferable that the polyhedron formed by the skeleton lines O of the multiple cell partitions 21 constituting the skeleton part 2 (and thus the approximate polyhedron formed by the cell holes C) is one that can be space-filling (can be arranged without gaps). This allows the skeleton lines O of the multiple cell partitions 21 constituting the skeleton part 2 to be connected to each other so as to fill the space, thereby improving the characteristics of the porous structure as a cushioning material. In this case, the polyhedron formed by the skeleton lines O of the multiple cell partitions 21 constituting the skeleton part 2 (and thus the approximate polyhedron formed by the cell holes C) may include only one type of polyhedron as in this example, or may include multiple types of polyhedrons. Here, with respect to the polyhedron, the "type" refers to the shape (the number of constituent faces and the shape), and specifically, two polyhedrons that have different shapes (the number of constituent faces and the shape) are treated as two types of polyhedrons, but two polyhedrons that have the same shape and only different dimensions are treated as the same type of polyhedron. Examples of polyhedrons formed by the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 that can fill space and include only one type of polyhedron include a regular triangular prism, a regular hexagonal prism, a cube, a rectangular parallelepiped, and a rhombic dodecahedron, in addition to a Kelvin tetradecahedron. As shown in the examples of the figures, when the shape of the skeleton lines O of the cell partitions 21 is a Kelvin tetradecahedron (truncated octahedron), it is easier to reproduce the characteristics of a cushioning material equivalent to that of a general polyurethane foam manufactured through a process of foaming by chemical reaction, compared to other shapes. Also, when the shape of the skeleton lines O of the cell partitions 21 is a Kelvin tetradecahedron (truncated octahedron), it is possible to obtain mechanical properties equal to those in the XYZ directions. When the polyhedron formed by the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 can fill space and includes multiple types of polyhedrons, examples of the polyhedrons include a combination of a regular tetrahedron and a regular octahedron, a combination of a regular tetrahedron and a truncated tetrahedron, a combination of a regular octahedron and a truncated hexahedron, etc. Note that these are examples of combinations of two types of polyhedrons, but combinations of three or more types of polyhedrons are also possible.
Furthermore, the polyhedron formed by the skeleton lines O of the multiple cell partition sections 21 that make up the skeleton section 2 (and thus the approximate polyhedron formed by the cell holes C) can be, for example, any regular polyhedron (a convex polyhedron in which all faces are congruent regular polygons and the number of faces that contact all vertices is equal), a semi-regular polyhedron (a convex polyhedron in which all faces are regular polygons and all vertices have congruent shapes (the types and order of regular polygons that meet at the vertices are the same) other than a regular polyhedron), a prism, a pyramid, etc.
Furthermore, the skeleton lines O of some or all of the cell partitions 21 among the multiple cell partitions 21 constituting the skeleton 2 may have a three-dimensional shape other than a polyhedron (e.g., a sphere, an ellipsoid, a cylinder, etc.). Furthermore, some or all of the cell holes C among the multiple cell holes C constituting the skeleton 2 may have an approximately three-dimensional shape other than an approximately polyhedron (e.g., an approximately sphere, an approximately ellipsoid, an approximately cylinder, etc.).

The multiple annular portions 211 constituting the cell partition 21 include small annular portions 211S and large annular portions 211L of different sizes, which makes it possible to further reduce the gaps (spacing) between the cell holes C constituting the skeletal portion 2. Furthermore, when the small annular portions 211S and the large annular portions 211L have different shapes as in this example, it becomes possible to further reduce the gaps (spacing) between the cell holes C constituting the skeletal portion 2.
However, the multiple annular portions 211 constituting the cell partition 21 may each have the same size and/or shape. When the annular portions 211 constituting the cell partition 21 have the same size and shape, it is possible to obtain equal mechanical properties in each of the X, Y, and Z directions.

As in this example, the skeleton lines O of some or all (in this example, all) of the annular portions 211 constituting the cell partitioning portion 21 (and thus some or all (in this example, all) of the virtual surfaces V1 constituting the cell partitioning portion 21) are substantially polygonal, which makes it possible to reduce the intervals between the cell holes C constituting the skeleton portion 2. In addition, the behavior of the compression and restoration deformation of the skeleton portion 2 in response to the application and release of an external force becomes better as a seat pad, particularly as a seat pad for a vehicle. In addition, since the shape of the annular portion 211 (and thus the shape of the virtual surface V1) is simplified, the manufacturability and ease of adjustment of the characteristics can be improved. Note that, when at least one annular portion 211 (and thus at least one virtual surface V1 of the virtual surfaces V1 constituting the skeleton portion 2) of the annular portions 211 constituting the skeleton portion 2 satisfies this configuration, a similar effect can be obtained, although there may be differences in degree.
In addition, the skeleton line O of at least one of the annular portions 211 constituting the skeleton portion 2 (and thus at least one of the virtual surfaces V1 constituting the skeleton portion 2) may be any substantially polygonal shape other than the substantially regular hexagon or substantially regular quadrangle as in this example, or a planar shape other than a substantially polygonal shape (for example, a circle (a perfect circle, an ellipse, etc.)). When the shape of the skeleton line O of the annular portion 211 (and thus the shape of the virtual surface V1) is a circle (a perfect circle, an ellipse, etc.), the shape of the annular portion 211 (and thus the shape of the virtual surface V1) becomes simple, which improves manufacturability and ease of adjusting the characteristics, and provides more uniform mechanical characteristics. For example, when the shape of the skeletal line O of the annular portion 211 (and thus the shape of the virtual surface V1) is an ellipse (horizontal ellipse) that is elongated in a direction approximately perpendicular to the direction in which the load is applied, the annular portion 211, and thus the skeletal portion 2 (and thus the porous structure 1) are more easily deformed (softer) in response to the input of load than when the shape is an ellipse (vertical ellipse) that is elongated in a direction approximately parallel to the direction in which the load is applied.

In this example, it is preferable that the skeleton 2 has at least one cell hole C having a diameter of 5 mm or more. This makes it easier to manufacture the porous structure 1 using a 3D printer. If the diameter of each cell hole C of the skeleton 2 is less than 5 mm, the structure of the skeleton 2 becomes too complicated, and it may be difficult to generate three-dimensional shape data (CAD data, etc.) representing the three-dimensional shape of the porous structure 1, or 3D printing data generated based on the three-dimensional shape data, on a computer.
Incidentally, since conventional porous structures are manufactured through a process of foaming by chemical reaction, it is not easy to form cell holes C having a diameter of 5 mm or more.
Furthermore, by having the skeletal portion 2 have cell holes C with a diameter of 5 mm or more, the breathability and ease of deformation of the skeletal portion 2 can be easily improved.
From this viewpoint, it is preferable that the diameter of each of the cell holes C constituting the skeleton portion 2 is 5 mm or more.
The larger the diameter of the cell hole C, the easier it is to manufacture the porous structure 1 using a 3D printer, and the easier it is to improve the breathability and ease of deformation. From this viewpoint, it is preferable that the diameter of at least one (preferably all) of the cell holes C in the skeleton 2 is 8 mm or more, and even more preferably 10 mm or more.
On the other hand, if the cell holes C of the skeleton 2 are too large, it becomes difficult to form the outer edge (outer contour) shape of the skeleton 2 (and thus the porous structure 1) neatly (smoothly), and the shape precision of the cushion body 5 may decrease, resulting in a poor appearance. In addition, the characteristics as a cushioning material (e.g., a seat pad, particularly a seat pad for a vehicle) may not be sufficiently good. Therefore, from the viewpoint of improving the appearance and the characteristics as a cushioning material (e.g., a seat pad, particularly a seat pad for a vehicle), the diameter of each cell hole C of the skeleton 2 is preferably less than 30 mm, more preferably 25 mm or less, and even more preferably 20 mm or less.
The more cell holes C that the porous structure 1 has and that satisfy the above-mentioned numerical ranges for diameter, the more likely it is that the above-mentioned effects can be obtained. From this viewpoint, it is preferable that the diameter of each of the cell holes C that constitute the porous structure 1 satisfies at least one of the above-mentioned numerical ranges. Similarly, it is more preferable that the average value of the diameters of the cell holes C that constitute the porous structure 1 satisfies at least one of the above-mentioned numerical ranges.
In addition, the diameter of the cell hole C refers to the diameter of the circumscribed sphere of the cell hole C when the cell hole C has a shape other than a strictly spherical shape as in this example.

If the cell holes C of the skeleton 2 are too small, the structure of the skeleton 2 becomes too complicated, and as a result, it may be difficult to generate three-dimensional shape data (CAD data, etc.) representing the three-dimensional shape of the porous structure 1, or 3D modeling data generated based on the three-dimensional shape data, on a computer, making it difficult to manufacture the porous structure 1 using a 3D printer. From the viewpoint of facilitating the manufacture of the porous structure 1 using a 3D printer, it is preferable that the diameter of the cell hole C having the smallest diameter among the cell holes C constituting the skeleton 2 is 0.05 mm or more, and more preferably 0.10 mm or more. When the diameter of the cell hole C having the smallest diameter is 0.05 mm or more, it can be modeled with the resolution of a high-performance 3D printer, and when it is 0.10 mm or more, it can be modeled with the resolution of not only a high-performance 3D printer but also a general-purpose 3D printer.

Fig. 14 is a drawing for explaining a modified example of the cell partition 21 of the porous structure 1, and corresponds to Fig. 13. In each example described in this specification, the porous structure 1 may include one or more membranes 3 in addition to the skeleton 2, as in the modified example shown in Fig. 14.
The membrane 3 extends on an imaginary plane V1 defined by the annular inner peripheral edge 2111 of the annular portion 211, thereby covering the imaginary plane V1 defined by the annular portion 211. In the porous structure 1 of the example of FIG. 14, at least one of the imaginary planes V1 constituting the skeleton portion 2 is covered with the membrane 3. The membrane 3 is made of the same material as the skeleton portion 2 and is integrally formed with the skeleton portion 2. In the example of FIG. 14, the membrane 3 is configured to be flat. However, the membrane 3 may be configured to be non-flat (for example, curved (curved)).
The membrane 3 preferably has a thickness smaller than the width W0 (FIG. 11) of the bone portion 2B.
The membrane 3 prevents the two cell holes C sandwiching the virtual surface V1 from communicating with each other through the virtual surface V1, and ventilation through the virtual surface V1 is not possible, which leads to a decrease in the overall air permeability of the porous structure 1. By adjusting the number of the virtual surfaces V1 that constitute the porous structure 1 that are covered with the membrane 3, the overall air permeability of the porous structure 1 can be adjusted, and various air permeability levels can be achieved according to requirements. From the viewpoint of promoting the compression/restoration deformation of the porous structure 1 and the interaction between the porous structure 1 and the viscous fluid F, it is not preferable that all of the virtual surfaces V1 that constitute the porous structure 1 are covered with the membrane 3. In other words, it is preferable that at least one of the virtual surfaces V1 that constitute the porous structure 1 is not covered with the membrane 3 and is open, and it is more preferable that all of the virtual surfaces V1 that constitute the porous structure 1 are not covered with the membrane 3 and are open.
As described above, conventional porous structures are manufactured through a process of foaming by chemical reaction, and therefore it is difficult to form the membranes in the communication holes that communicate with each cell at the desired positions and in the desired number. When the porous structure 1 is manufactured by a 3D printer as in this example, the information on the membrane 3 is included in the 3D printing data read into the 3D printer in advance, so that the membranes 3 can be reliably formed at the desired positions and in the desired number.
At least one of the small imaginary surfaces V1S constituting the skeleton 2 may be covered with the film 3. And/or at least one of the large imaginary surfaces V1L constituting the skeleton 2 may be covered with the film 3.

Next, with reference to Figures 15 to 16, other examples of the porous structure 1 that can be provided in the cushion body 5 according to any embodiment of the present invention will be described, focusing on the points that differ from the examples in Figures 11 to 13.
15 and 16, only the configuration of the bone portion 2B of the skeleton portion 2 of the porous structure 1 is different from the examples of FIGS. 11 to 13.
The porous structure 1 may or may not comprise the membrane 3 (FIG. 14) described above.
15, the skeleton lines O of the cell partitions 21 constituting the skeleton 2 each form a Kelvin tetradecahedron, and accordingly, the cell holes C each form an approximately Kelvin tetradecahedron. However, as described in the explanation of the examples of Figures 11 to 13, also in the example of Figure 15, the skeleton lines O of the cell partitions 21 constituting the skeleton 2 each may have any shape, and accordingly, the cell holes C may also have any shape.

Fig. 15 is a plan view showing another example of the porous structure 1 that can be provided in the cushion body 5 according to any embodiment of the present invention, and corresponds to Fig. 12. Fig. 16 shows the bone portion 2B of this example alone. Fig. 16(a) shows the natural state where no external force is applied to the bone portion 2B, and Fig. 16(b) shows the state where an external force is applied to the bone portion 2B. Figs. 15 and 16 show the central axis (skeleton line O) of the bone portion 2B.
As shown in FIG. 15 and FIG. 16(a), each bone portion 2B of the skeleton 2 is composed of a bone constant portion 2B1 that extends while maintaining a constant cross-sectional area, and a pair of bone change portions 2B2 that extend from the bone constant portion 2B1 to the connecting portion 2J while gradually changing the cross-sectional area on both sides of the extension direction of the bone constant portion 2B1. In this example, each bone change portion 2B2 extends from the bone constant portion 2B1 to the connecting portion 2J while gradually increasing the cross-sectional area. Note that, not limited to this example, the same effect can be obtained even if only some of the bone portions 2B constituting the skeleton 2 satisfy this configuration. In addition, some or all of the bone portions 2B constituting the skeleton 2 may have the bone change portion 2B2 only at one end of the bone constant portion 2B1, and the other end of the bone constant portion 2B1 may be directly connected to the connecting portion 2J, and in this case, the same effect can be obtained, although there may be differences in degree.
Here, the cross-sectional areas of the bone constant portion 2B1 and the bone changed portion 2B2 refer to the cross-sectional areas of cross sections perpendicular to the skeleton line O of the bone constant portion 2B1 and the bone changed portion 2B2, respectively.
In this example, each bone portion 2B constituting the porous structure 1 is composed of a bone constant portion 2B1 and a bone change portion 2B2, and the cross-sectional area of the bone change portion 2B2 gradually increases from the bone constant portion 2B1 toward the joint portion 2J, so that the bone portion 2B has a constricted shape that narrows toward the bone constant portion 2B1 in the vicinity of the boundary between the bone constant portion 2B1 and the bone change portion 2B2. Therefore, when an external force is applied, the bone portion 2B is easily buckled and deformed at the constricted portion and the middle portion of the bone constant portion 2B1, and the porous structure 1 is easily compressed and deformed. This provides behavior and characteristics equivalent to those of a general polyurethane foam manufactured through a process of foaming by chemical reaction. This also makes the surface of the porous structure 1 softer to the touch. Therefore, for example, when sitting, especially at the beginning of sitting, a softer feeling is given to the seated person. Such a soft feel is generally widely preferred, and is also preferred by occupants of luxury car seat pads (e.g., occupants sitting in the back seat when a chauffeur is driving the car and passengers are seated in the back seat).

When the bone portion 2B has a bone fixed portion 2B1 at least in a portion thereof as in this example, the ratio A0/A1 of the cross-sectional area A0 ( FIG. 16( a )) of the bone fixed portion 2B1 to the cross-sectional area A1 ( FIG. 16( a )) of the end 2B21 on either side (preferably both sides) of the bone portion 2B is
0.15≦A0/A1≦2.0
It is preferable that the ratio A0/A1 is satisfied. As a result, the touch of the surface of the porous structure 1 can be made not too soft or too hard, but moderately hard, as a characteristic of the seat pad (particularly a vehicle seat pad). Therefore, for example, when sitting, especially at the beginning of sitting, the seated person is given a feeling of moderate hardness. The smaller the ratio A0/A1, the softer the touch of the surface of the porous structure 1. If the ratio A0/A1 is less than 0.15, the touch of the surface of the porous structure 1 may be too soft, which may be undesirable as a characteristic of the seat pad (particularly a vehicle seat pad), and it is difficult to manufacture using a 3D printer, which is undesirable in terms of manufacturability. If the ratio A0/A1 is more than 2.0, the touch of the surface of the porous structure 1 may be too hard, which may be undesirable as a characteristic of the seat pad (particularly a vehicle seat pad).
It is more preferable that the ratio A0/A1 is 0.5 or more.
More specifically, in the example of Figures 15 and 16, the bone portion 2B has a bone constant portion 2B1 and a pair of bone change portions 2B2 continuous with both sides of the bone constant portion 2B1, and each bone change portion 2B2 extends from the bone constant portion 2B1 to the joint portion 2J while gradually increasing the cross-sectional area, and the ratio A0/A1 is less than 1.0. This allows the touch feeling of the surface of the porous structure 1 to be relatively soft as a characteristic of a seat pad (particularly a vehicle seat pad). Such a soft touch is generally widely preferred, and is also preferred by passengers in the seat pad of a luxury car (for example, passengers sitting in the back seat when a chauffeur is driving a car and passengers are sitting in the back seat).
In addition, each bone part 2B constituting the skeletal part 2 may satisfy this configuration, or only some of the bone parts 2B constituting the skeletal part 2 may satisfy this configuration, and in either case, the same effect can be obtained, although to varying degrees.

Instead of the example of FIG. 15-FIG. 16, the bone change portion 2B2 may extend from the bone constant portion 2B1 to the connecting portion 2J while gradually decreasing the cross-sectional area. In this case, the bone constant portion 2B1 has a larger (thicker) cross-sectional area than the bone change portion 2B2. As a result, when an external force is applied, the bone constant portion 2B1 is less likely to deform, and instead, the bone change portion 2B2 (particularly the portion on the connecting portion 2J side) is relatively prone to buckling, and the porous structure 1 is less likely to be compressed and deformed. As a result, the touch of the surface of the porous structure 1 becomes harder, and mechanical properties of high hardness are obtained. Therefore, for example, when sitting, especially at the beginning of sitting, the seated person is given a harder feel. Such behavior is not easy to obtain with a general polyurethane foam manufactured through a process of foaming by chemical reaction. This configuration can accommodate users who prefer a harder feel. Such a hard feel is preferred by occupants in seat pads of sports cars, for example, which are used during rapid acceleration, deceleration, and lane changes.
When the bone transformation portion 2B2 extends from the bone constant portion 2B1 to the joint portion 2J while gradually decreasing its cross-sectional area, the ratio A0/A1 exceeds 1.0.
In addition, each bone part 2B constituting the skeletal part 2 may satisfy this configuration, or only some of the bone parts 2B among the bone parts 2B constituting the skeletal part 2 may satisfy this configuration, and in either case, the same effect can be obtained, although to different degrees.

In the examples of Figures 11 to 13 described above in the first embodiment, the bone portion 2B does not have a bone-changing portion 2B2, and is composed of only a bone-fixed portion 2B1. In this case, the cross-sectional area of the bone portion 2B is constant over its entire length. The touch feeling of the surface of the porous structure 1 when an external force is applied is medium hardness. This configuration can accommodate users who prefer a medium hardness feel. In addition, it can be suitably applied to seat pads of all types of vehicles, such as luxury cars and sports cars.
In this case, the ratio A0/A1 is 1.0.
In addition, each bone part 2B constituting the skeletal part 2 may satisfy this configuration, or only some of the bone parts 2B among the bone parts 2B constituting the skeletal part 2 may satisfy this configuration, and in either case, the same effect can be obtained, although to varying degrees.

Returning to the example of Figures 15-16, in this example, in each bone portion 2B constituting the skeletal portion 2, the bone constant portion 2B1 has a smaller cross-sectional area than the bone changed portion 2B2 and the connecting portion 2J. More specifically, the cross-sectional area of the bone constant portion 2B1 is smaller than the cross-sectional area of any portion of the bone changed portion 2B2 and the connecting portion 2J (excluding the boundary portion between the bone constant portion 2B1 and the bone changed portion 2B2). In other words, the bone constant portion 2B1 is the portion of the skeletal portion 2 with the smallest cross-sectional area (thinnest). As a result, as in the above, when an external force is applied, the bone constant portion 2B1 is more likely to deform, and thus the porous structure 1 is more likely to be compressed and deformed. This makes the surface of the porous structure 1 feel softer to the touch.
The cross-sectional area of the joint 2J refers to the cross-sectional area of a cross section perpendicular to the skeleton line O of the joint 2J.
In addition, without being limited to this example, only some of the bone parts 2B among the bone parts 2B that constitute the skeletal part 2 may satisfy this configuration, and even in that case, the same effect can be obtained, although to different degrees.

15-16, in each bone portion 2B constituting the skeletal portion 2, the bone constant portion 2B1 has a smaller width than the bone changed portion 2B2 and the connecting portion 2J. More specifically, the width of the bone constant portion 2B1 is smaller than the width of any portion of the bone changed portion 2B2 and the connecting portion 2J (excluding the boundary portion between the bone constant portion 2B1 and the bone changed portion 2B2). In other words, the bone constant portion 2B1 is the portion of the skeletal portion 2 with the smallest width (thinnest). This also makes the bone constant portion 2B1 more easily deformed when an external force is applied, which makes the surface of the porous structure 1 feel softer to the touch.
The widths of bone constant portion 2B1, bone changed portion 2B2, and connecting portion 2J refer to the maximum widths in a cross section perpendicular to the skeleton line O of bone constant portion 2B1, bone changed portion 2B2, and connecting portion 2J, respectively. The skeleton line O of connecting portion 2J is the portion of the skeleton line O that corresponds to connecting portion 2J. For reference, width W0 of bone constant portion 2B1 and width W1 of bone changed portion 2B2 are shown in Figure 16(a).
In addition, without being limited to this example, only some of the bone parts 2B among the bone parts 2B that constitute the skeletal part 2 may satisfy this configuration, and even in that case, the same effect can be obtained, although to different degrees.

In each of the above-mentioned examples, from the viewpoint of simplifying the structure of the porous structure 1 and, by extension, ease of manufacturing with a 3D printer, the width W0 (FIG. 16) of the bone constant portion 2B1 is preferably 0.05 mm or more, and more preferably 0.10 mm or more. When the width W0 is 0.05 mm or more, modeling is possible with the resolution of a high-performance 3D printer, and when it is 0.10 mm or more, modeling is possible with the resolution of not only a high-performance 3D printer but also a general-purpose 3D printer.
On the other hand, from the viewpoint of improving the accuracy of the outer edge (outer contour) shape of the porous structure 1, from the viewpoint of reducing the gaps (spacing) between the cell holes C, and from the viewpoint of improving the characteristics as a cushioning material, it is preferable that the width W0 (Figure 16) of the bone fixed portion 2B1 be 0.05 mm or more and 2.0 mm or less.
It is preferable that each of the bone parts 2B constituting the skeletal part 2 satisfy this configuration, but it is also acceptable for only some of the bone parts 2B constituting the skeletal part 2 to satisfy this configuration, and even in this case, a similar effect can be obtained, although to varying degrees.

As shown in Figure 16, in this example, each bone portion 2B constituting the skeletal portion 2 has a bone change portion 2B2 having one or more (in this example, three) inclined surfaces 2B23 on its side, and these inclined surfaces 2B23 are inclined (inclined at less than 90°) with respect to the extension direction of the bone change portion 2B2, and the width W2 gradually increases from the bone constant portion 2B1 toward the connecting portion 2J.
This also makes it easier for the bone portion 2B to buckle and deform at the constricted portion near the boundary between the bone constant portion 2B1 and the bone transformed portion 2B2 when an external force is applied, and thus makes it easier for the porous structure 1 to undergo compressive deformation. This makes the surface of the porous structure 1 softer to the touch.
Here, the extension direction of the bone changed portion 2B2 is the extension direction of the central axis (skeletal line O) of the bone changed portion 2B2. Moreover, the width W2 of the inclined surface 2B23 of the bone changed portion 2B2 refers to the width of the inclined surface 2B23 when measured along a cross section perpendicular to the skeletal line O of the bone changed portion 2B2.
In addition, without being limited to this example, only some of the bone parts 2B among the bone parts 2B that constitute the skeletal part 2 may satisfy this configuration, and even in that case, the same effect can be obtained, although to different degrees.

In the example of Figs. 15 and 16, each bone portion 2B constituting the skeleton 2 is columnar, and the bone constant portion 2B1 and the bone changed portion 2B2 each have a cross-sectional shape of an equilateral triangle.
This simplifies the structure of the porous structure 1, making it easier to model it using a 3D printer. In addition, it is easy to reproduce the mechanical properties of general polyurethane foam manufactured through a process of foaming by chemical reaction. This improves the properties of the porous structure 1 as a cushioning material. Furthermore, by forming the bone portion 2B in a columnar shape in this way, the durability of the porous structure 1 can be improved compared to the case where the bone portion 2B is replaced with a thin membrane-like portion.
The cross-sectional shapes of the bone constant portion 2B1 and the bone changed portion 2B2 are the shapes in a cross section perpendicular to the central axis (skeleton line O) of the bone constant portion 2B1 and the bone changed portion 2B2, respectively.
In addition, without being limited to this example, only some of the bone parts 2B among the bone parts 2B that constitute the skeletal part 2 may satisfy this configuration, and even in that case, the same effect can be obtained, although to different degrees.
In addition, in all or some of the bone parts 2B constituting the skeletal part 2, the cross-sectional shapes of the bone constant part 2B1 and the bone changed part 2B2 may be polygonal other than an equilateral triangle (triangle other than an equilateral triangle, quadrangle, etc.) or may be circular (perfect circle, ellipse, etc.), and the same effect as in this example can be obtained in this case. The cross-sectional shapes of the bone constant part 2B1 and the bone changed part 2B2 may be different from each other. The cross-sectional shapes of each bone part 2B may be uniform along its extension direction, or may be non-uniform along its extension direction. The cross-sectional shapes of each bone part 2B may be different from each other.

The cushion body and the method for manufacturing the cushion body of the present invention can be used for cushion bodies for any purpose, but are suitable for use in, for example, any vehicle seat and any seat pad (vehicle seat pad), and are particularly suitable for use in vehicle seats and vehicle seat pads.

5: Cushion body,
6: first bag body; 6a, 6b: parts of the first bag body; 61: first space; 62: opening;
7: second bag body, 71: second space, 72: opening,
8: Orifice partition body, 81: Orifice,
9a to 9c: parts,
F: viscous fluid,
1: Porous structure, 1a: Second porous structure (porous structure), 1b: First porous structure (porous structure),
2: Skeleton, 2B: Bone, 2Be: End of bone, 2B1: Bone constant part, 2B2: Bone change part, 2B21: End of bone change part on the joining part side, 2B22: End of bone change part on the bone constant part side, 2B23: Sloping surface of bone change part, 2J: Joint part, 21: Cell partition part, 211: Annular part, 211L: Large annular part, 211S: Small annular part, 2111: Inner peripheral edge part of annular part,
3: membrane,
C: cell hole, O: skeleton line, V1: virtual surface, V1L: large virtual surface, V1S: small virtual surface, 302: seat pad,
311: main pad portion, 312: side pad portion, 313: recess, 314: main body portion,
FS: Seat side (front surface), SS: Side surface, BS: Back surface,
400: 3D printer, 410: control unit, 420: modeling unit, 421: laser irradiator, 430: support stand, 440: container, LL: ultraviolet laser light, LR: liquid resin, 500, 500a to 500c: 3D modeling data

Claims (9)

A porous structure made of a flexible resin or rubber;
A first bag body that defines a first space therein;
A cushion body comprising:
The first bag contains the porous structure and is filled with a viscous fluid.
The porous structure has a skeleton throughout its entirety,
The skeleton portion is
A plurality of bones;
a plurality of connecting portions each connecting an end portion of the plurality of bone portions to each other;
It is composed of
The cushion body does not include any valve . A second bag body that defines a second space therein; and
an orifice partition that defines an orifice that communicates the first space and the second space;
The cushion body of claim 1 further comprising: The cushion body according to claim 1 or 2, wherein the first bag body is integrally formed with the porous structure or is bonded to the porous structure. the skeleton has a plurality of cell partitions that partition cell pores therein,
Each of the cell partitions has a plurality of annular portions each configured in an annular shape,
the plurality of annular portions constituting the cell partition are connected to each other such that imaginary planes defined by the respective inner circumferential side edges do not intersect with each other,
Each of the annular portions is composed of a plurality of the bone portions and a plurality of the connecting portions,
Each of the virtual surfaces is flat,
The cushion body according to any one of claims 1 to 3, wherein the cell holes are defined by the plurality of annular portions and the plurality of imaginary surfaces defined by the plurality of annular portions, respectively. the plurality of annular portions constituting the cell partition include one or more small annular portions and one or more large annular portions,
Each of the small annular portions defines a small imaginary flat surface by its inner peripheral edge,
The cushion body according to claim 4 , wherein each of the large annular portions defines, by its inner peripheral edge, a large imaginary surface which is flat and has an area larger than that of the small imaginary surface. The cushion body according to claim 5, wherein the small imaginary surface and the large imaginary surface have different shapes. The cushion body according to any one of claims 4 to 6, wherein each of the cell holes has a shape of a substantially Kelvin tetrahedron. The cushion body according to any one of claims 1 to 7 is used in a seat pad. A method for manufacturing a cushion body, comprising the steps of: manufacturing a portion of the cushion body according to any one of claims 1 to 8 other than the viscous fluid using a 3D printer.

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