JP2023055603A - cushion - Google Patents

Abstract

To provide a cushion capable of suppressing displacement of the ischium, and reducing force applied to the ischium.SOLUTION: A cushion according to an embodiment is a cushion 1 constituted of a flexible raw material. The cushion 1 includes a seat part 2 having a hip support part 4 where a user's hip is placed, and a thigh support part 5 where a user's thigh is placed. The hip support part 4 has a pair of ischium support parts 6 aligned along a longitudinal direction as a view from a user seated on the seat part 2. Each ischium support part 6 has a recess 6b hollowed from an upper surface 4b of the hip support part 4 in the state where the ischium is placed. The curvature of each recess 6b is larger than the curvature of the upper surface 4b. The seat part 2 has an inclined plane 7 extending obliquely upward toward the thigh support part 5 from the hip support part 4.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a cushion on which a user's buttocks and thighs rest.

Various types of cushions on which a user's buttocks and thighs are placed are conventionally known. Japanese Patent Application Laid-Open No. 2020-168583 describes a posture holder having a buttock support. The posture retainer includes a buttocks support that supports the buttocks of a seated person, a front projection that projects forward from the buttocks support, and an upper projection that extends upward from the buttocks support. The front projections support the undersides of the seated person's thighs. The upper projection has a lumbar support that supports the iliac portion of the lumbar region of the seated person.

Japanese Patent Application Laid-Open No. 2014-12130 describes a chair cushion. A chair cushion includes a cushion body and a cover. The cushion body includes a seat portion against which the buttocks of the seated person abuts, and a back portion against which the back of the seated person abuts. The inclination angle of the back portion with respect to the seat portion in side view is 95° or more and 110° or less. The seat has two ischial bone corresponding portions, and the two ischial bone corresponding portions have a concave surface shape.

JP 2020-168583 A JP 2014-12130 A

By the way, with a cushion, a user sitting on the cushion leans forward or leans backward. When the user leans forward or leans backward, the user's sit bones may shift in the front-rear direction. Sitting for long periods of time with the sit bones out of alignment can injure the user's shoulders, neck, or lower back. Also, high pressure on the sit bones can cause the user to strain the buttocks. Therefore, it is required to suppress the displacement of the sit bones and to reduce the force applied to the sit bones.

An object of the present disclosure is to provide a cushion that can suppress displacement of the sit bones and reduce the force applied to the sit bones.

A cushion according to one aspect of the present disclosure is a cushion made of a flexible material. The cushion includes a seat portion having a buttock support on which the user's buttocks rest and a thigh support on which the user's thighs rest. The buttocks support has a pair of ischium supporters arranged in the left-right direction as seen from the user seated on the seat. Each ischium support has a recess recessed from the upper surface of the buttocks support with the sitbone placed thereon. The curvature of each recess is greater than the curvature of the top surface. The seating portion has an inclined surface extending obliquely upward from the buttock support portion toward the thigh support portion.

The cushion includes a seat having a buttock support and a thigh support. Since this cushion is made of a flexible material, it can gently support the user's buttocks supported by the buttocks support and the user's thighs supported by the thigh support. The buttocks support has a pair of ischium supporters aligned in the left-right direction, and each of the pair of ischium supporters has a recess recessed from the upper surface of the buttocks supporter. Therefore, when the user sits on the seat portion, the ischial bones of the user's buttocks enter the recesses, thereby suppressing displacement of the ischial bones and reducing the force applied to the ischial bones. The curvature of each recess is greater than the curvature of the upper surface of the buttock support. Therefore, the seat bones of the user can be more reliably inserted into the concave portion having a large curvature, so that displacement of the seat bones when the user is seated can be more reliably suppressed. Furthermore, the seat portion has an inclined surface extending obliquely upward from the buttocks support portion toward the thigh support portion. Therefore, since the height of the buttock support portion is lower than the height of the thigh support portion, it is possible to prevent the buttocks from slipping forward, and to more reliably suppress forward slippage of the sit bones. Therefore, it is possible to reduce the force applied to the sit bones and to suppress the slippage of the sit bones.

A cushion according to another aspect of the present disclosure is a cushion made of a flexible material. The cushion includes a seat portion having a buttock support on which the user's buttocks rest and a thigh support on which the user's thighs rest. The buttocks support has a pair of ischium supporters arranged in the left-right direction as seen from the user seated on the seat. Each ischium support has a through hole penetrating downward from the upper surface of the buttocks support. The seating portion has an inclined surface extending obliquely upward from the buttock support portion toward the thigh support portion.

The cushion includes a seat having a buttock support and a thigh support. Since this cushion is made of a flexible material, it can gently support the user's buttocks supported by the buttocks support and the user's thighs supported by the thigh support. The buttock support has a pair of ischium support parts arranged in the left-right direction, and each of the pair of ischium support parts has a through-hole penetrating downward from the upper surface of the buttock support part. Therefore, when the user sits on the seat, the ischial bones of the user's buttocks enter the through-holes, thereby suppressing displacement of the ischial bones and reducing the force applied to the ischial bones. Furthermore, the seat portion has an inclined surface extending obliquely upward from the buttocks support portion toward the thigh support portion. Therefore, since the height of the buttock support portion is lower than the height of the thigh support portion, it is possible to prevent the buttocks from slipping forward, and to more reliably suppress forward slippage of the sit bones. Therefore, it is possible to reduce the force applied to the sit bones and to suppress the slippage of the sit bones.

Each ischial support may have a tapered surface located between an inner wall of the through hole defining the through hole and an upper surface of the buttock support. In this case, since the tapered surface exists between the inner wall of the through hole and the upper surface of the buttocks support, the inner wall of the through hole is smoothly connected to the upper surface of the buttocks support via the tapered surface. Therefore, when the user sits on the seat portion, the ischial bone that has entered the through hole can be gently supported on the tapered surface, so that the force applied to the ischial bone can be further reduced.

The cushion may include a lumbar support portion that abuts the user's lumbar region from behind. The lumbar support may have a convex sacral support that supports the user's sacrum from behind. In this case, the waist support portion abuts against the waist of the user sitting on the seat. At this time, the user's pelvis can be prevented from shifting downward by abutting the convex sacrum support portion against the user's sacrum. Therefore, the posture of the user can be properly maintained.

The sacral support may have a protruding surface. The protruding surface may have a curved shape protruding forward. In this case, the user can easily feel the force of pushing the sacrum forward compared to the case where the projecting surface is planar.

The lumbar support may have a lumbar support that supports the user's lumbar spine from behind above the sacral support. In this case, the lumbar spine located above the sacrum is supported by the lumbar spine support. Therefore, it is possible to support the lumbar vertebrae of the user seated on the seat and more reliably suppress displacement of the pelvis.

The lumbar support section may have ilium support sections that support the ilium of the user on both left and right sides of the lumbar support section as seen from the user seated on the seat. In this case, a pair of iliac bones located on the right and left sides of the lumbar spine are supported by the iliac supporting portions. Therefore, displacement of the pelvis of the user seated on the seat can be more reliably suppressed.

The shape of each ischial support portion in plan view may extend in the long axis direction and in the short axis direction intersecting the long axis direction, and the length in the long axis direction may be longer than the length in the short axis direction. . The extension lines of the pair of long axes of the pair of ischial support portions may intersect each other at a position closer to the thigh support portion than the pair of ischial support portions. In this case, the pair of ischium support portions has an inverted V shape in plan view. In addition, the ischial bones of the user sitting on the seat have an inverted V shape in plan view. Therefore, by matching the shape of the pair of ischium support parts to the shape of the user's ischium, the fit of the ischium to the ischium support parts can be improved, and displacement of the ischium can be reliably suppressed.

The intersection angle of the extension lines of the pair of long axes may be 40° or more and 150° or less. In this case, it is possible to match the direction of the long axis of the ischium supporting portion with the direction of the ischial bone of the user sitting on the seating portion, so that the fit of the ischium to the ischium supporting portion can be further improved.

The thickness of the thigh support portion when the user is seated on the seat may be thinner than the thickness of the portion of the seat other than the thigh support when the user is seated on the seat. In this case, when the user sits on the seat, the thigh support becomes thinner than the portion of the seat other than the thigh support. You can avoid it.

The amount of deformation of the thigh support when the user sits on the seat may be greater than the amount of deformation of the portion of the seat other than the thigh support when the user sits on the seat. . In this case, when the user sits on the seat, the amount of downward deformation of the thigh support is greater than that of the portion of the seat other than the thigh support. position can be prevented from rising too much.

The thigh support may have a recess defining a space with the mounting surface on which the cushion is mounted. In this case, when the user's thigh is placed on the thigh support, the thigh support easily deforms to reduce the space. Therefore, since the thigh support portion can be deformed more easily downward, it is possible to suppress the rise of the thigh and further improve the sitting comfort.

The projected area of the lower surface of the cushion may be smaller than the projected area of the cushion in plan view. In this case, since the area of the seating portion in plan view is larger than the area of the lower surface of the cushion facing the seating surface on which the cushion is placed, the seating surface has a smaller area than the seating portion in plan view. A cushion can be placed. Therefore, since the cushion can be placed on the seat surface of various chairs, the versatility of the cushion is improved.

According to the present disclosure, it is possible to suppress displacement of the sit bones and reduce the force applied to the sit bones.

It is a perspective view which shows the cushion which concerns on embodiment. It is a top view which shows the cushion which concerns on embodiment. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; It is a front view which shows the cushion which concerns on embodiment. FIG. 3 is a cross-sectional view taken along line BB of FIG. 2; 1 is a diagram schematically showing the spine and pelvis of a body; FIG. (a) is a diagram schematically showing the pelvis of the body. (b) is a diagram schematically showing the spine and pelvis of the body. (a) is a graph showing the position of a user's sit bone in plan view. (b) is a graph showing the height position of the user's sacrum. FIG. 11 is a side view showing a cushion according to a first modified example; (a) is a front view of a seating portion of a cushion according to a first modified example. (b) is a plan view of the waist support portion of the cushion according to the first modified example. FIG. 11 is a plan view of a seating portion according to a first modified example; (a) is a perspective view showing a cushion according to a second modified example. (b) is a perspective view showing a cushion according to a third modified example. FIG. 11 is a perspective view showing a cushion according to a fourth modified example; FIG. 11 is a plan view showing a cushion according to a fourth modified example; FIG. 15 is a cross-sectional view taken along line CC of FIG. 14; FIG. 11 is a front view showing a cushion according to a fourth modified example; FIG. 15 is a cross-sectional view taken along line DD of FIG. 14; It is a bottom view which shows the cushion which concerns on a 4th modification. FIG. 11 is a perspective view showing a cushion according to a fifth modified example; FIG. 11 is a plan view showing a cushion according to a fifth modified example; It is a bottom view which shows the cushion which concerns on a 5th modification. FIG. 11 is a front view showing a cushion according to a fifth modified example; 21 is a cross-sectional view taken along line EE of FIG. 20; FIG. It is an experimental result (measurement data) which shows the pressure distribution which concerns on a comparative example which is an example when a user sits down on the chair without a cushion. (a) is an experimental result (actual measurement data) showing the pressure distribution in the seating portion and the sacrum support portion when the user sits on the cushion according to Example 1; (b) is an experimental result (actual measurement data) showing the pressure distribution in the seating portion and the sacrum support portion when the user sits on the cushion according to Example 2; (a) is an experimental result (actual measurement data) showing the pressure distribution at the thigh support portion when the user sits on the cushion according to Example 3 in a forward leaning posture. (b) is an experimental result (actual measurement data) showing the pressure distribution at the thigh support portion when the user sits on the cushion according to Example 4 in a forward leaning posture.

Embodiments of the cushion according to the present disclosure will be described below with reference to the drawings. Elements that are the same or correspond to the description of the drawings are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate. In addition, the drawings may be partially simplified or exaggerated for easy understanding, and the dimensional ratios and the like are not limited to those described in the drawings.

A cushion according to the present disclosure is made of a flexible material. "Flexible material" refers to a cushioning material that deforms when the body is put on it and receives a load. The cushion includes a seat portion having a buttock support on which the user's buttocks rest and a thigh support on which the user's thighs rest.

"User" indicates a user of the cushion, for example, a person sitting on the cushion. "Buttocks" refers to the bulging portion of the lower back of the body and is that part of the body that lies below the waist and above the thighs. "Thigh" refers to the portion of the thigh from the root of the leg to the knee.

"Sitting" means sitting on a cushion. "Seat" refers to the portion of the cushion against which the buttocks and thighs abut when sitting on the cushion. The buttock support has a pair of sit bone supports. The "sciatica" indicates the lowest part of the pelvis when the user is seated on the seat.

FIG. 1 is a perspective view showing a cushion 1 according to this embodiment. As shown in FIG. 1 , the cushion 1 includes a horizontally extending seat portion 2 and a waist support portion 3 extending upward from the seat portion 2 . The cushion 1 is made of flexible material. For example, the cushion 1 is made of urethane foam.

As an example, the cushion 1 is formed by urethane molding. When the cushion 1 is made of urethane foam and formed by urethane molding, the cushion 1 made of a flexible material can be easily manufactured. The cushion 1 is, for example, a core material housed in a cloth cover.

In addition, said flexible material contains a thermoplastic elastomer, for example. The flexible material may be a material having elasticity to the extent that it deforms according to the load when the body is placed on it. The flexible material may be a resin (eg, polypropylene, polyester, or polyethylene) that deforms when the body rests on it and receives a load. The flexible material may be a mesh material. In this way, the type of flexible material can be changed as appropriate.

The seat portion 2 extends in a first direction D1 and a second direction D2 intersecting the first direction D1. The first direction D1 is the front-rear direction when viewed from the user seated on the seat portion 2, and the second direction D2 is the left-right direction when viewed from the user seated on the seat portion 2. The seat portion 2 has a thickness in a third direction D3 that intersects both the first direction D1 and the second direction D2. For example, the third direction D3 is the vertical direction.

Hereinafter, the forward direction when viewed from the user seated on the seat portion 2 may be referred to as "front", "front side" or "forward", and the opposite direction to the forward direction may be referred to as "rear" or "rear side". ” or “rear”. However, these directions are for the convenience of explanation, and do not limit the position or orientation of each part.

FIG. 2 is a plan view of the cushion 1. FIG. As shown in FIGS. 1 and 2, the length A1 of the cushion 1 in the first direction D1 is 30 cm or more and 90 cm or less. Also, the length A1 may be 40 cm or more and 50 cm or less, and is 45 cm as an example. The length A2 of the cushion 1 in the second direction D2 is, like the length A1, 30 cm or more and 90 cm or less, or 40 cm or more and 50 cm or less, for example 45 cm.

The seat portion 2 has a buttock support portion 4 on which the user's buttocks are placed, and a thigh support portion 5 on which the user's thighs are placed. The buttock support part 4 and the thigh support part 5 are arranged side by side along the first direction D1. The buttock support part 4 has a pair of ischium support parts 6 for supporting the ischial bones of the user seated on the seat part 2 .

The ischium supporting portion 6 is formed on the upper surface 4b of the buttocks supporting portion 4 and is recessed from the upper surface 4b. 3 is a cross-sectional view taken along the line AA of FIG. 2. FIG. As shown in FIGS. 2 and 3, the buttocks support 4 has a pair of ischium supports 6 arranged along the second direction D2. The ischial support portion 6 has a recess 6 b recessed from the upper surface 4 b of the buttock support portion 4 . The concave portion 6b is defined, for example, by a corner portion 6c that is a boundary portion with the upper surface 4b and a curved surface 6h located inside the corner portion 6c in a plan view. The curvature of the recessed portion 6b (curved surface 6h) is greater than the curvature of the upper surface 4b of the buttock support portion 4. As shown in FIG. In addition, the recessed part 6b does not need to be exposed. The recessed portion 6b may be recessed from the upper surface 4b of the buttock support portion 4 in a state where the user's ischium is placed thereon. For example, the recessed portion 6b may be filled with a material that is more likely to be recessed than the buttock support portion 4.

The shape of the ischial support portion 6 in plan view is a shape having a long axis 6d and a short axis 6f. That is, the ischial bone support portion 6 extends in both the long axis direction D4 in which the long axis 6d extends and the short axis direction D5 in which the short axis 6f extends. For example, the shape of the ischium supporting portion 6 in plan view is an oval shape. As an example, the shape of the ischium supporting portion 6 in plan view is an elliptical shape. However, the shape of the ischium support portion 6 in a plan view is not limited to an oval shape or an elliptical shape, and may be a rectangular shape, a rounded rectangular shape, a diamond shape, or a rounded diamond shape, and can be changed as appropriate. .

An extension line L1 of the long axis 6d of one of the pair of ischium support parts 6 and an extension line L2 of the long axis 6d of the other of the pair of ischium support parts 6 intersect each other. are doing. An intersection angle θ1 between the extension line L1 and the extension line L2 is, for example, 40° or more and 150° or less. The intersection angle θ1 may be 50° or more, 60° or more, 75° or more, or 90° or more. Also, the intersection angle θ1 may be 135° or less, 120° or less, or 110° or less. As an example, the intersection angle θ1 is 100°.

An intersection point P between the extension line L1 and the extension line L2 is positioned closer to the thigh support portion 5 than the pair of ischium support portions 6 . The intersecting portion P is positioned closer to the thigh support portion 5 than the center 6g of each ischial support portion 6 in plan view. The crossing portion P is located on the opposite side of the lumbar support portion 3 when viewed from the pair of ischium support portions 6 . As a result, the pair of ischium support portions 6 have an inverted V-shape in plan view (plan view when the waist support portion 3 is positioned above the seat portion 2).

The length of the major axis 6d of the ischial bone supporting portion 6 is, for example, 5 cm or more and 10 cm or less. As an example, the long axis 6d has a length of 7 cm. The length of the minor axis 6f of the ischial bone supporting portion 6 is, for example, 3 cm or more and 9 cm or less. As an example, the minor axis 6f has a length of 5 cm.

A distance A5 between the centers 6g of the pair of ischium support portions 6 (distance between the centers of the pair of ischium support portions 6) is, for example, 7 cm or more and 15 cm or less. As an example, the distance A5 is 10 cm. The positions of the pair of centers 6g in the first direction D1 are, for example, the same. The distance from the waist support 3 to the center 6g is, for example, 5 cm or more and 15 cm or less. As an example, the distance from the waist support 3 to the center 6g is 10 cm. When each length and each distance are within the ranges of the above values, the user's ischium can be fitted to each of the pair of ischium support portions 6 more favorably.

The seat portion 2 has an inclined surface 7 extending obliquely upward from the buttock support portion 4 toward the thigh support portion 5 . For example, the seat portion 2 has a pair of inclined surfaces 7 arranged along the second direction D2. For example, the inclined surface 7 exhibits a linear shape in a cross section along a plane extending in the first direction D1 and the third direction D3. The inclination angle θ2 of the inclined surface 7 with respect to the lower surface 1b of the cushion 1 is, for example, 5° or more and 15° or less. As an example, the tilt angle θ2 is 10°.

When the inclination angle θ2 is 5° or more and 15° or less, it is possible to make it more difficult for the user's sit bones seated on the seat portion 2 to shift forward. Note that unlike the above example, the inclined surface 7 has a curved shape in a cross section along a plane extending in the first direction D1 and the third direction D3 (for example, the inclination angle θ2 increases toward the thigh support portion 5). It may have a curvilinear shape).

For example, the seat portion 2 has a pair of thigh support portions 5 arranged along the second direction D2 and a convex portion 8 located between the pair of thigh support portions 5 . Each of the pair of thigh support portions 5 is positioned on the front side of the inclined surface 7 . For example, the thigh support 5 presents a convex shape. The back side of the user's thigh is placed on the thigh support 5 . That is, the thigh support part 5 supports the back side of the user's thigh. The thigh support portion 5 has, for example, a top portion 5b located at the front end of the inclined surface 7 and a curved portion 5c extending forward and obliquely downward from the top portion 5b.

A convex portion 8 indicates a portion protruding from the inclined surface 7 . For example, in plan view, the convex portion 8 has a shape extending along the first direction D1. The width of the convex portion 8 in a plan view increases toward the front. The height of the convex portion 8 increases toward the center in the second direction D2.

The convex portion 8 has a top portion 8b and an inclined portion 8c extending forward and obliquely downward from the top portion 8b. The shape of the inclined portion 8c in plan view is, for example, a triangular shape that widens toward the front. The top portion 8b of the convex portion 8 is located on the rear side of the top portion 5b of the thigh support portion 5. As shown in FIG.

FIG. 4 is a front view of the cushion 1 as seen from the front side. As shown in FIGS. 2 to 4, the seat portion 2 has a pair of protrusions 9 located on both end sides of the inclined surface 7 in the second direction D2. For example, the protrusion 9 connects the waist support 3 and the thigh support 5 to each other. The convex portion 9 extends along the first direction D1.

A top portion 9b of the convex portion 9 is, for example, a curved surface. As an example, the height of the top portion 9b of the convex portion 9 is higher than the height of the top portion 5b of the thigh support portion 5 . The height of the top portion 9b of the convex portion 9 may be the same as the height of the top portion 8b of the convex portion 8 . By providing the above projections 8 and projections 9, the thighs of the user can be easily placed on respective positions on both sides of the projections 8 in the second direction D2 between the pair of projections 9. can be done. In addition, the shapes and the like of the convex portions 8 and 9 are not limited to the above-described modes and can be changed as appropriate. Moreover, a cushion that does not have at least one of the protrusions 8 and 9 may be used.

Next, the waist support portion 3 will be described. For example, the waist support portion 3 is curved so as to protrude forward toward both end sides in the second direction D2. 5 is a cross-sectional view taken along line BB of FIG. 2. FIG. As shown in FIGS. 3 to 5, the waist support portion 3 extends upward from the end (rear end) of the seat portion 2 in the first direction D1.

The lumbar support section 3 has, for example, a general section 10 extending in both the second direction D2 and the third direction D3, and a sacrum support section 11 located in the center of the second direction D2 below the general section 10. . A general portion 10 indicates a portion of the lumbar support portion 3 other than the sacrum support portion 11 . The general portion 10 has a first portion 10b extending upward from the rear end of the buttock support portion 4, and a second portion 10c extending upward and obliquely forward from the upper end of the first portion 10b.

The thickness of the first portion 10b in the first direction D1 decreases upward. The first portion 10b is composed of an inner surface 10d that curves rearward and obliquely upward, and an outer surface 10f that curves outward in the first direction D1. In addition, the first portion 10b has recesses 10g recessed along the second direction D2 at both ends thereof in the second direction D2.

The second portion 10c is positioned above the first portion 10b and the sacral support 11, for example. The second portion 10c has a lumbar spine support portion 12 that supports the user's lumbar spine from behind, and ilium support portions 13 that support the ilium of the user on both sides of the lumbar spine support portion 12 in the second direction D2. For example, a pair of iliac support portions 13 are provided on both sides of the lumbar support portion 12 in the second direction D2.

For example, the lumbar support section 12 is defined by a front end 3b positioned above the lumbar support section 3 and an inclined surface 3c extending obliquely downward from the front end 3b. Each of the pair of ilium support portions 13 protrudes to both end sides in the second direction D2 and protrudes forward. The lumbar spine support part 12 supports the user's lumbar spine by coming into contact with the lumbar spine from behind. The ilium supporting portion 13 supports the pair of ilium by facing the user's ilium from both end sides in the second direction D2.

For example, the sacral support portion 11 has a convex shape protruding forward. The sacrum supporting portion 11 protrudes forward from the front surface 10h of the general portion 10 . As an example, the shape of the sacral support 11 seen from the front has a long axis 11b and a short axis 11c. For example, the shape of the sacral support 11 seen from the front is oval. As an example, the shape of the sacral support 11 seen from the front is elliptical.

However, the shape of the sacral support portion 11 viewed from the front side may be a shape other than an oval shape or an elliptical shape. can be changed as appropriate. For example, the upper end 11d of the projecting surface 11g of the sacral support portion 11 is flush with the front surface 10h of the general portion 10. As shown in FIG. A protruding surface 11g of the sacral support portion 11 protrudes forward from the inner surface 10d of the general portion 10 . The projecting surface 11g is, for example, inclined forward as it goes upward. As an example, the projecting surface 11g has a flat shape.

The length of the long axis 11b of the sacrum support portion 11 is, for example, 5 cm or more and 15 cm or less. As an example, the length of major axis 11b is 10 cm. The length of the short axis 11c of the sacrum support portion 11 is, for example, 3 cm or more and 10 cm or less. As an example, the minor axis 11c has a length of 7 cm. Also, the height of the center 11h of the sacral support portion 11 relative to the bottom portion 4c of the buttocks support portion 4 in the third direction D3 is, for example, 5 cm or more and 15 cm or less. The height of the center 11h is, for example, 9 cm or more and 10 cm or less. The sacrum can be supported by the sacral support 11 by bringing the sacrum support 11 into contact with the user's sacrum.

By the way, in the body of a person sitting on a cushion, it is desirable that the human pelvis is horizontal in the left-right direction and that the pelvis stands straight. FIG. 6 is a diagram schematically showing a human spine E1 and pelvis E2. FIG. 7(a) is a diagram schematically showing the pelvis E2. FIG. 7(b) is a diagram schematically showing the spine E1 and the pelvis E2 viewed from the lateral direction of the body.

As shown in FIGS. 6, 7(a), and 7(b), in the body of a person seated on the cushion, an imaginary line L3, which is a straight line connecting the protrusion of the ilium E3 and the pubic bone E4, extends in the vertical direction. It is desirable to extend along If the state in which the virtual line L3 is inclined continues for a long period of time, problems may occur in that a person becomes easily tired, has a bad posture, and easily gains weight (thickness in the lower half of the body).

In addition, it is desirable to support the rear end of the sacrum E5 and the lower ends of the pair of ischial bones E6 so as not to shift from each other from the viewpoint of good posture maintenance. Specifically, by suppressing the forward displacement of the lower ends of the sit bones E6 and the downward displacement of the sacrum E5, a good posture can be maintained, and the above-described problems can be suppressed even when sitting for a long time. becomes possible.

Next, the effects obtained from the cushion 1 according to this embodiment will be described in detail. As shown in FIGS. 1 and 2, the cushion 1 comprises a seat 2 having a buttock support 4 and a thigh support 5 . Since the cushion 1 is made of a flexible material, it can gently support the user's buttocks supported by the buttock supporter 4 and the user's thighs supported by the thigh supporter 5 .

The buttock support portion 4 has a pair of ischium support portions 6 arranged along the second direction D2 (horizontal direction), and each of the pair of ischium support portions 6 has a concave portion 6b recessed from the upper surface 4b of the buttock support portion 4. . Therefore, when the user sits on the seat portion 2, the seat bones E6 of the user's buttocks enter the recesses 6b, thereby suppressing the displacement of the seat bones E6 and reducing the force applied to the seat bones E6. can. The curvature of each concave portion 6b is greater than the curvature of the upper surface 4b of the buttock support portion 4. As shown in FIG. Therefore, the seat bones E6 of the user can be reliably inserted into the concave portion 6b having a large curvature, so that displacement of the seat bones E6 when the user is seated can be more reliably suppressed.

Further, the seat portion 2 has an inclined surface 7 extending obliquely upward from the buttock support portion 4 toward the thigh support portion 5 . Therefore, since the height of the buttock support part 4 is lower than the height of the thigh support part 5, it is possible to prevent the buttocks from slipping forward, and to more reliably suppress the forward slippage of the ischium E6. Therefore, the force applied to the ischium E6 can be reduced, and displacement of the ischium E6 can be suppressed.

The cushion 1 according to this embodiment includes a waist support portion 3 that abuts on the waist of the user from behind. The lumbar support section 3 has a convex sacrum support section 11 that supports the user's sacrum E5 from behind. Therefore, the waist support part 3 contacts the waist of the user sitting on the seat part 2 . At this time, the user's pelvis E2 can be prevented from being displaced downward by abutting the user's sacrum E5 from behind with the convex sacrum support portion 11 . Therefore, the posture of the user can be appropriately maintained.

The shape of each ischium support portion 6 in plan view extends in the major axis direction D4 and in the minor axis direction D5 that intersects with the major axis direction D4, and the length of the major axis 6d extending in the major axis direction D4 is It has a shape longer than the length of the minor axis 6f extending to D5. Extension lines L1 and L2 of the pair of long axes 6d of the pair of ischium support portions 6 intersect each other at a position closer to the thigh support portion 5 than the center 6g of the pair of ischium support portions 6. As shown in FIG. Therefore, the pair of ischium support portions 6 has an inverted V shape in plan view. In addition, the seat bone E6 of the user sitting on the seat portion 2 has an inverted V shape in plan view. Therefore, by matching the shape of the pair of sit bone support portions 6 to the shape of the sit bone E6 of the user, it is possible to reliably suppress the slippage of the sit bone E6 while improving the fitting feeling of the sit bone E6 to the sit bone support portion 6. .

In this embodiment, the intersection angle θ1 of the extension lines L1 and L2 of the pair of major axes 6d is 40° or more and 150° or less. Therefore, it is possible to match the direction of the long axis 6d of the ischium support part 6 with the direction of the ischium E6 of the user sitting on the seat part 2, so that the fit of the ischium E6 to the ischium support part 6 is further improved. can do.

The lumbar support section 3 has a lumbar support section 12 that supports the user's lumbar vertebrae from behind above the sacrum support section 11 . Therefore, the lumbar vertebrae positioned above the sacrum E5 are supported by the lumbar vertebrae support portion 12 . Therefore, it is possible to support the lumbar vertebrae of the user sitting on the seat portion 2 and more reliably suppress displacement of the pelvis E2.

The lumbar support section 3 has an ilium support section 13 that supports the ilium E3 of the user on both sides (left and right sides) of the lumbar support section 12 in the second direction D2 as viewed from the user seated on the seat section 2 . Therefore, a pair of iliac bones E3 positioned on the right and left sides of the lumbar spine are supported by the iliac supporting portions 13. As shown in FIG. Therefore, displacement of the pelvis E2 of the user seated on the seat portion 2 can be more reliably suppressed.

FIG. 8(a) is a graph showing the positions of a pair of human sit bones E6 in plan view. FIG. 8(b) is a graph showing the position of the human sacrum E5 (the position of the rearward projecting portion of the sacrum E5) when viewed from the front side. Each of FIGS. 8(a) and 8(b) shows the results of measurements performed on each of the 10 subjects.

FIG. 8(a) shows the position of the ischium E6 when the person is seated on a square cushion with one side of 40 cm. In the graph of FIG. 8(a), the center of the cushion is the origin. The back surface of the cushion (the surface against which the subject's back rests) is located at +20 cm on the vertical axis in FIG. 8(a), and the bottom of the vertical axis indicates the front. The horizontal axis in FIG. 8A indicates the left-right direction.

As shown in FIG. 8(a), the distance between the pair of sit bones E6 was 10 cm to 11 cm. Specifically, the mean value for female subjects was 10.9 cm, and the mean value for male subjects was 10.2 cm. In addition, regarding the distance from the back surface of the cushion (the surface on which the subject's back hits) to the ischium in plan view, the average value for women was 9.5 cm, and the average value for men was 8.4 cm.

As described above, in the cushion 1, the distance between the centers 6g of the pair of ischial support portions 6 is 7 cm or more and 15 cm or less, and the distance from the waist support portion 3 to the centers 6g is 5 cm or more and 15 cm or less. In this case, since the position and the center-to-center distance of the ischium support portion 6 can be matched to the position of the ischium E6 of the subject in plan view, the position of the ischium E6 of the subject can be adjusted to the position of the ischium support portion 6. can be fitted. Therefore, it is possible to more reliably suppress the displacement of the ischium E6.

FIG. 8B is a graph showing the height of the sacrum E5 relative to the bottom 4c of the buttocks support 4 of the subject seated on the seat 2 (height of the most backward protruding portion of the sacrum E5). The horizontal axis of FIG. 8B indicates the second direction D2, and the vertical axis of FIG. 8B indicates the third direction D3. As shown in FIG. 8(b), the height of the sacrum E5 was 6 cm or more and 13.5 cm or less. The average height of the sacrum E5 in female subjects was 8.8 cm, and the average height of the sacrum E5 in male subjects was 9.4 cm.

In the cushion 1, the height of the center 11h of the sacrum support portion 11 with respect to the bottom portion 4c is 5 cm or more and 15 cm or less. In this case, since the height position of the sacrum support portion 11 can be matched with the height position of the sacrum E5 described above, the position of the sacrum E5 of the subject can be fitted to the position of the sacrum support portion 11. Therefore, the position of the sacrum E5 can be more reliably fitted to the position of the sacral support portion 11. FIG. As a result, displacement of the sacrum E5 can be suppressed more reliably.

Next, the cushion 21 according to the first modified example will be described. FIG. 9 is a side view of the cushion 21 viewed from the second direction D2. A part of the configuration of the cushion 21 is the same as a part of the configuration of the cushion 1 described above. Therefore, in the following description, description overlapping with the configuration of the cushion 1 will be omitted as appropriate.

The cushion 21 is made of foamed urethane, for example. As an example, the cushion 21 is produced by two-dimensional cutting. The cushion 21 has a plurality of protrusions 21b formed on the surface with which the user's body comes into contact, and a plurality of slits 21c formed on the surface opposite to the surface with which the user's body comes into contact.

The cushion 21 has a seat portion 22 and a waist support portion 23 . The seat portion 22 has a buttock support portion 24 on which the user's buttocks are placed, and a thigh support portion 25 on which the user's thighs are placed. The seat portion 22 has an inclined surface 29 extending obliquely upward from the buttock support portion 24 toward the thigh support portion 25 .

The seating portion 22 has a plurality of protrusions 21b arranged along both the first direction D1 and the second direction D2, and the plurality of protrusions 21b are arranged in a grid pattern in plan view. Inclined surface 29 is a virtual surface including a plurality of convex portions 21 b , and the height of inclined surface 29 increases from hip support portion 24 toward thigh support portion 25 .

The height of the convex portion 21 b gradually increases from the buttock support portion 24 toward the thigh support portion 25 . Each of the plurality of slits 21c extends along the second direction D2. The slit 21c has a linear portion 21f extending upward from the lower surface 21d of the cushion 21 and an extended portion 21g extending from the upper end of the linear portion 21f.

FIG. 10(a) is a front view of the seating portion 22 viewed from the front side. As shown in FIG. 10(a), the seat portion 22 has a pair of thigh support portions 25 arranged along the second direction D2. Each of the pair of thigh support portions 25 is formed by a plurality of protrusions 21b. The height of the convex portion 21b in each thigh support portion 25 is positioned between the pair of thigh support portions 25 and on both end sides of the pair of thigh support portions 25 in the second direction D2. It is lower than the height of the convex portion 21b. The shape of the thigh support part 25 seen from the front side presents a concave shape that is more recessed than the other parts. As a result, it is possible to improve the fit of the user's thighs to the respective thigh support portions 25 .

The seat portion 22 has, for example, a plurality of upper slits 22b extending along the first direction D1 and arranged along the second direction D2. The upper slit 22b has, for example, a linear portion 22c extending downward from between the pair of convex portions 21b and an extended portion 22d extending at the lower end of the linear portion 22c.

For example, between a pair of upper slits 22b arranged along the second direction D2, a plurality of convex portions 21b are arranged along the second direction D2. The plurality of protrusions 21b constitute, for example, a protrusion group G1 made up of a plurality of protrusions 21b arranged along the second direction D2. The seat portion 22 has, for example, a plurality of convex portion groups G1.

As a result, the plurality of convex portion groups G1 can be deformed independently of each other, and each convex portion 21b can be deformed according to the shape of the user's thighs and the like. Good pressure dispersion can be achieved. As an example, three protrusions 21b are arranged between a pair of upper slits 22b. An upper slit extending in the second direction D2 may be formed instead of the upper slit 22b or together with the upper slit 22b.

FIG. 10(b) is a plan view showing the waist support portion 23. FIG. As shown in FIGS. 9, 10(a), and 10(b), the waist support portion 23 includes a plurality of projections 23b facing forward and a plurality of projections 23b facing away from the projections 23b. and a slit 23c. The plurality of protrusions 23b are arranged in a grid on the front surface of the waist support 23, for example.

The plurality of convex portions 23b are arranged so as to line up along each of the second direction D2 and the third direction D3. The height of the protrusion 23b located at the center in the second direction D2 and the center in the third direction D3 is the highest, and the height of the protrusion 23b decreases as the distance from the protrusion 23b increases. That is, the plurality of protrusions 23b has a quadrangular pyramid shape as a whole.

The plurality of slits 23c are arranged so as to line up along the third direction D3, and each slit 23c extends linearly along the second direction D2, for example. The slit 23c has a linear portion 23f extending forward from the rear surface 23d of the waist support portion 23, and an extended portion 23g extending at the front end of the linear portion 23f.

The lumbar support 23 has a sacrum support 31 projecting forward. The sacrum support portion 31 is formed by a plurality of convex portions 23b. The protrusion 23 b of the sacrum support portion 31 protrudes more than the protrusions 23 b positioned above the sacral support 31 and below the sacrum support 31 . The shape of the sacral support portion 31 as viewed along the second direction D2 is a convex shape that protrudes more than the other portions. That is, the sacrum support portion 31 is configured including the highest (most protruding) convex portion 23b. Thereby, the user's sacrum E5 can be more reliably supported by the sacrum support portion 31. FIG.

The lumbar support 23 has a lumbar support 32 that supports the user's lumbar vertebrae from behind. The lumbar support portion 32 is formed by a convex portion 23b projecting forward. The lumbar support section 32 is composed of, for example, a plurality of protrusions 23b arranged along the second direction D2 at the upper end of the lumbar support section 23 .

The waist support portion 23 has, for example, a plurality of front slits 23h extending along the third direction D3 and aligned along the second direction D2. The front slit 23h has, for example, a narrow portion 23j extending rearward from between the pair of convex portions 23b, the width of the front slit 23h narrowing toward the rear, and an extended portion 23k expanding at the rear end of the narrow portion 23j. and

For example, between a pair of front slits 23h arranged along the second direction D2, a plurality of protrusions 23b are arranged along the second direction D2. The plurality of protrusions 23b has, for example, a protrusion group G2 including a plurality of protrusions 23b arranged along the second direction D2. The waist support portion 23 constitutes, for example, a plurality of convex portion groups G2.

As a result, the plurality of convex portion groups G2 can be deformed independently of each other, and each convex portion 23b can be deformed according to the shape of the user's back or hips, thereby dispersing the body pressure of the user's back, hips, and the like. can improve the quality. As an example, three protrusions 23b are arranged between a pair of front slits 23h. A front slit extending in the second direction D2 may be formed instead of the front slit 23h or together with the front slit 23h.

FIG. 11 is a plan view schematically showing the seating portion 22. As shown in FIG. For ease of understanding, illustration of the convex portion 21b is omitted in FIG. As shown in FIG. 11, the buttocks support 24 has a pair of ischium supports 26 aligned along the second direction D2. The ischium supporting portion 26 is formed on the upper surface 24b of the buttocks supporting portion 24 and is formed in a slit shape on the upper surface 24b.

The ischium supporting portion 26 has a slit 27 recessed with respect to the upper surface 24b. By having the slit 27 , the sit bone support portion 26 is more likely to be recessed than the portion of the buttock support portion 24 other than the sit bone support portion 26 . Since the amount of deformation of the ischial support portion 26 is larger than that of the portion of the buttocks support portion 24 other than the ischial support portion 26, the curvature of the ischial support portion 26 when depressed is larger than the curvature of the upper surface 24b.

For example, the ischium supporting portion 26 has an oval shape in plan view. The overall shape and position of the ischial bone supporting portion 26 in plan view are, for example, the same as the shape and position of the ischial bone supporting portion 6 in plan view. The ischial support portion 26 has a plurality of slits 27 extending in directions inclined in both the first direction D<b>1 and the second direction D<b>2 and deformation portions 28 located between the plurality of slits 27 . Since the deformable portion 28 is positioned between the plurality of slits 27 , the deformable portion 28 is a portion that is more easily deformed than the portion of the buttock support portion 24 other than the deformable portion 28 .

For example, the slit 27 penetrates the seat portion 22 in the third direction D3. The ischial support portion 26 has, for example, a pair of slits 27 . A pair of slits 27 extend parallel to each other. As an example, the slit 27 has a curved portion 27b that curves like a wave, and extended portions 27c that extend at both ends of the curved portion 27b. The extended portion 27c is, for example, extended in an arc shape at the end of the curved portion 27b.

In the above example, the example in which the ischium supporting portion 26 has a pair of slits 27 extending parallel to each other has been described. However, the pair of slits 27 may not extend parallel to each other. Alternatively, the ischial support portion 26 may have only one slit 27 . Thus, the orientation and number of slits 27 are not particularly limited.

In the cushion 21 configured as described above, each of the pair of ischium support portions 26 has a recess recessed from the upper surface 24b of the buttocks support portion 24 when the user sits on the seat portion 22 . Further, the curvature of the concave portion is larger than the curvature of the upper surface 24b of the buttock support portion 24. As shown in FIG. Therefore, since the seat bone E6 of the user can be securely inserted into the concave portion of the seat bone support portion 26 having a large curvature, it is possible to more reliably suppress the displacement of the seat bone E6 when the user is seated. is obtained.

Next, a cushion 41 according to a second modification will be described with reference to FIG. 12(a). As shown in FIG. 12( a ), the cushion 41 differs from the cushion 1 in that it does not have the lumbar support section 12 and the iliac support section 13 . The waist support portion 43 of the cushion 41 has a convex portion 44 that rises toward the center in the second direction D2 and a convex sacrum support portion 11 that protrudes forward from the front surface 44b of the convex portion 44 .

Further, a cushion 51 according to a third modification will be described with reference to FIG. 12(b). As shown in FIG. 12(b), the cushion 51 differs from the cushion 1 in that it does not have the waist support portion 3. As shown in FIG. The cushion 51 has the aforementioned seat portion 2 and a protruding portion 52 protruding from the rear end of the seat portion 2 . The upper surface of the projecting portion 52 is, for example, a curved surface.

Furthermore, a cushion 61 according to a fourth modification will be described. 13 is a perspective view showing the cushion 61. FIG. 14 is a plan view showing the cushion 61. FIG. 15 is a cross-sectional view taken along line CC of FIG. 14. FIG. FIG. 16 is a front view showing the cushion 61. FIG. 17 is a cross-sectional view taken along line DD of FIG. 14. FIG. 18 is a bottom view showing the cushion 61. FIG.

As shown in FIG. 13, the cushion 61 has a seating portion 62 . The seat 62 has a buttock support 64 and a thigh support 65 . The seat portion 62 has a pair of thigh support portions 65 arranged along the second direction D2. The pair of thigh support portions 65 are provided, for example, at positions separated from each other. A pair of user's thighs is placed on each of the pair of thigh support portions 65 . The buttock support 64 has a pair of sit bone supports 66 . Unlike each ischial support 6 of the cushion 1 described above, each ischial support 66 does not have a recess 6b. Each ischial support 66 has a through hole 66b. The through-hole 66b penetrates downward from the upper surface 64b of the buttock support portion 64 . Note that the through hole 66b does not have to be exposed. For example, the through-hole 66b may be filled with a material that is more likely to be depressed than the portion of the buttocks support portion 64 other than the ischium support portion 66 .

As shown in FIG. 14, the shape of the through hole 66b in plan view may be similar to the shape of the ischial bone support portion 6 in plan view of the cushion 1 described above. As an example, the shape of the through-hole 66b in plan view is an oval shape (or an elliptical shape). The position of the through hole 66b is, for example, the same as the position of the recess 6b of the cushion 1 described above.

The seat portion 62 is formed with a ventilation hole 62a. The air hole 62a penetrates downward from the upper surface 64b of the buttock support portion 64 or the upper surface of the thigh support portion 65. As shown in FIG. The upper end of the inner wall that defines the vent hole 62a may be R-chamfered so as to be rounded. In plan view, a plurality of air holes 62a may be arranged so as to line up from the rear to the front. For example, in a plan view (a plan view when the waist support portion 73 is positioned above the seating portion 62), a plurality of (six as an example) vent holes 62a are formed on both sides (left and right sides) of the second direction D2. may be placed in each of the

As an example, three ventilation holes 62a are arranged on each of both sides in the second direction D2. For example, two vent holes 62a are aligned along the second direction D2, and the distance between the two vent holes 62a aligned along the second direction D2 is from the buttock support 64 to the thigh support 65. It gets longer as you go. As an example, the plurality of air holes 62a are arranged in a V-shape in plan view. For example, in the cushion 61, the through hole 66b is formed by urethane molding, and the vent hole 62a is formed by punching. In this case, the mold used for manufacturing the cushion 61 can be made unnecessary for forming the ventilation hole 62a, so that the shape of the mold can be simplified. Furthermore, when liquid urethane is molded with the mold, an escape path for air in the liquid urethane can be secured, so that the cushion 61 can be beautifully finished.

FIG. 15 is a cross-sectional view of the cushion 61 taken along a plane extending in the first direction D1 and the third direction D3. For example, the thickness of the thigh support portion 65 when the user is seated on the seat portion 62 is the thickness of the portion of the seat portion 62 other than the thigh support portion 65 when the user is seated on the seat portion 62. Thinner than thick. In this case, the thigh support portion 65 is deformed by the load so as to be thinner than the portion of the seat portion 62 other than the thigh support portion 65 . For example, the amount of deformation of the thigh support portion 65 when the user is seated on the seat portion 62 is greater than the amount of deformation of portions of the seat portion 62 other than the thigh support portion 65 . In this case, the thigh support portion 65 is more easily deformed by the load than the portion of the seat portion 62 other than the thigh support portion 65 .

For example, when the user sits on the seat portion 62 , the thigh support portion 65 deforms more than the inclined surface 7 when the user sits on the seat portion 62 . When the user sits on the seat portion 62 , the thigh support portion 65 may be deformed such that the inclination angle θ2 decreases from the inclined surface 7 toward the front end of the thigh support portion 65 . Further, in a state where no load is applied, the thickness of the thigh support portion 65 may be thinner than the thickness of the portion of the seat portion 62 other than the thigh support portion 65 . In this case as well, it is possible to prevent the thighs of the user from being raised too much.

Each thigh support portion 65 has a concave portion 65 d that is recessed in the thickness direction of the cushion 61 . The cushion 61 has a pair of recesses 65d. For example, the pair of recesses 65d are provided at positions separated from each other. The depth of the concave portion 65d becomes deeper as the distance from the buttock support portion 64 increases (toward the front side). For example, the thigh support portion 65 has a recess 65d defining a space B between itself and the mounting surface S on which the cushion 61 is mounted.

The concave portion 65d is formed in the lower surface 61b of the cushion 61, for example. The outer edge of the recess 65d is located on the lower surface 61b. The thickness of the portion of the thigh support portion 65 where the recess 65d is formed may be thinner than the thickness of the portion of the seat portion 62 other than the thigh support portion 65 . As an example, a space B defined between the recess 65d and the mounting surface S is formed so as to expand from the rear toward the front. A cross section of the space B perpendicular to the first direction D1 may widen from the rear toward the front. As an example, the outer edge of the recess 65d may be positioned on both the lower surface 61b and the inclined portion 65f.

As shown in FIG. 13, the cushion 61 has a general portion 70 and a waist support portion 73 . The waist support portion 73 has a convex portion 74 that rises toward the center in the second direction D2, and a convex sacrum support portion 71 that protrudes forward from the front surface 70h of the general portion 70 . As an example, the convex portion 74 and the convex portion 9 are continuous. As shown in FIG. 16, the waist support portion 73 as a whole may have an inverted U shape when viewed along the first direction D1.

As shown in FIGS. 16 and 17, the sacral support 71 has a projecting surface 71a. The protruding surface 71a has a curved shape protruding forward. For example, when viewed along the second direction D2, the protruding surface 71a may have a curved shape protruding forward from the front surface 70h. The height of the protruding surface 71a from the front surface 70h may increase from the outer edge of the protruding surface 71a toward the inner side of the protruding surface 71a.

The projected area of the lower surface 61b of the cushion 61 is smaller than the projected area of the cushion 61 in plan view. For example, as shown in FIG. 15, the inclined portion 65f of the thigh support portion 65 extends rearward and obliquely downward from the top portion 65e of the thigh support portion 65 when viewed along the second direction D2. exist. That is, the inclined portion 65f is inclined toward the center of the cushion 61 in the first direction D1 as it goes toward the lower surface 61b. The top portion 65e is located at the front end of the cushion 61, for example.

When viewed along the second direction D2, the outer surface 70f forming the first portion 70b of the general portion 70 is inclined toward the center of the cushion 61 in the first direction D1 toward the lower surface 61b. . As shown in FIG. 16, when viewed along the first direction D1, the cushion 61 has a sloped portion that slopes toward the center of the cushion 61 in the second direction D2 from the top portion 9b toward the bottom surface 61b. 9c. The cushion 61 has, for example, a pair of inclined portions 9c arranged along the second direction D2. The top portion 9b may be positioned at the end of the cushion 61 in the second direction D2. As an example, the cushion 61 has a boat shape that protrudes outward with increasing distance from the lower surface 61b.

Note that the thigh support portion 65 may not have the recess 65d. At least part of the thigh support portion 65 may be made of a material that is more easily deformed by a load than the material of the seat portion 62 other than the thigh support portion 65 .

Next, functions and effects obtained from the cushion 61 according to the fourth modified example will be described. As shown in FIG. 13, the buttock support 64 has a pair of ischium support 66 arranged along the second direction D2 (left-right direction). Each ischial support portion 66 has a through hole 66b penetrating downward from the upper surface 64b of the buttock support portion 64 . Therefore, when the user sits on the seat portion 62, the ischial bones E6 (see FIG. 6) of the user's buttocks enter the through holes 66b, thereby suppressing displacement of the ischial bones E6 and preventing the ischial bones E6 from being displaced. Such force can be reduced.

As shown in FIG. 17, in the fourth modification, the sacral support 71 has a projecting surface 71a. The protruding surface 71a has a curved shape protruding forward. Therefore, compared to the case where the protruding surface of the sacrum supporting portion is flat, the user can feel the force pushing the sacrum E5 (see FIG. 6) forward.

As described above, the thickness of the thigh support portion 65 when the user is seated on the seat portion 62 is the same as the thickness of the thigh support portion 65 of the seat portion 62 when the user is seated on the seat portion 62 . It may be thinner than the thickness of the part. In this case, when the user is seated on the seat portion 62, the thigh support portion 65 becomes thinner than the portion of the seat portion 62 other than the thigh support portion 65, so that the user's thighs are not affected. It is possible to prevent the position from rising too much. Therefore, the pressure applied to the seated user is easily distributed from the buttocks to the thighs, so that the pressure applied to the buttocks of the seated user can be reduced.

As described above, the amount of deformation of the thigh support portion 65 when the user sits on the seat portion 62 is the same as that of the thigh support portion 65 of the seat portion 62 when the user sits on the seat portion 62 . It may be larger than the deformation amount of the part. In this case, when the user sits on the seat portion 62, the amount of downward deformation of the thigh support portion 65 is greater than that of the portion of the seat portion 62 other than the thigh support portion 65. can prevent the thigh position from being too high. Therefore, the pressure applied to the seated user is easily distributed from the buttocks to the thighs, so that the pressure applied to the buttocks of the seated user can be reduced.

As shown in FIG. 15, the thigh support 65 has a recess 65d that is recessed in the thickness direction of the cushion 61. As shown in FIG. Therefore, the thigh support portion 65 can be made easier to deform than the portion of the seat portion 62 other than the thigh support portion 65 . Therefore, when the thigh is placed on the thigh support 65, the thigh support 65 can be moved downward more easily, so that the user's feeling of discomfort is reduced by making it difficult to lift the thigh. can be done. The depth of the concave portion 65d of the thigh support portion 65 becomes deeper as the distance from the buttock support portion 64 increases. That is, the depth of the recessed portion 65d of the thigh support portion 65 increases forward as viewed from the user seated on the seat portion 62 . Therefore, the front portion of the thigh support portion 65 can be more easily deformed downward than the buttock support portion 64, so that it is possible to more reliably prevent the thighs from rising. Therefore, it is possible to reduce the uncomfortable feeling of the user and improve the sitting comfort with respect to the cushion 61 .

The thigh support portion 65 has a concave portion 65d defining a space B between itself and the mounting surface S on which the cushion 61 is mounted. When the user's thigh is placed on the thigh support 65, the thigh support 65 is easily deformed so that the space B is reduced. Therefore, since the thigh support portion 65 can be easily deformed downward, it is possible to prevent the thigh from rising, thereby further improving the sitting comfort. Further, the thigh support part 65 sinks so that the space B is reduced, so that the user can feel that the thigh is wrapped by the thigh support part 65 .

As described above, in the fourth modification, the recess 65d is formed so that the space B defined between the recess 65d and the placement surface S expands from the rear to the front. When the user is seated on the seat 62, the space B of the thigh support 65 expands from the rear to the front, so that the front portion of the thigh support 65 can be deformed more easily. can. For example, part of the outer edge of the recess 65d is located on the lower surface 61b. In this case, the thigh support portion 65 can be easily sunk using the outer edge of the recess 65d located on the lower surface 61b as a fulcrum.

As described above, in the fourth modified example, the projected area of the lower surface 61b of the cushion 61 is smaller than the projected area of the cushion 61 in plan view. In this case, since the area of the seating portion 62 in plan view is larger than the area of the lower surface 61b of the cushion 61 facing the mounting surface S on which the cushion 61 is placed, it is smaller than the area of the seating portion 62 in plan view. The cushion 61 can be placed on the placement surface S having an area. Therefore, since the cushion 61 can be arranged on the seat surfaces of various chairs, the versatility of the cushion 61 is improved.

As described above, the top portion 65e is positioned at the front end of the cushion 61 in the fourth modification. The inclined portion 65f is inclined toward the center of the cushion 61 in the second direction D2 from the top portion 65e toward the lower surface 61b. When the user sits on the seat portion 62, the thigh support portion 65 deforms, for example, so that the entire thigh support portion 65 bends downward. In this case, the user's thighs are gently supported by the thigh support portion 65 deformed so as to bend downward as a whole.

As shown in FIG. 14, in the fourth modification, the seat portion 62 is formed with a ventilation hole 62a. The air hole 62a penetrates downward from the upper surface 64b of the buttock support portion 64 or the upper surface of the thigh support portion 65. As shown in FIG. Therefore, stuffiness between the user's buttocks and thighs and the seating portion 62 is suppressed.

As shown in FIG. 16, the waist support portion 73 as a whole may have an inverted U shape when viewed along the first direction D1. In this case, it is possible to make the waist support portion 73 less likely to break than the waist support portion 43 in which the convex portion 44 protrudes locally as shown in FIG. 12(a). Moreover, since the shape is simpler than that of the cushion 1 shown in FIG. 1, the cushion 61 can be manufactured easily.

Furthermore, a cushion 81 according to a fifth modified example will be described. 19 is a perspective view showing the cushion 81. FIG. 20 is a plan view showing the cushion 81. FIG. 21 is a bottom view showing the cushion 81. FIG. 22 is a front view showing the cushion 81. FIG. 23 is a cross-sectional view taken along line EE of FIG. 20. FIG. As shown in FIGS. 19-23, the cushion 81 differs from the cushion 61 in that it comprises a sit bone support 86 different from the sit bone support 66 and a sacral support 91 different from the sacrum support 71. .

In the cushion 81 , the buttock support 64 has a pair of sit bone supports 86 . Each ischial support portion 86 has a through hole 86b penetrating downward from the upper surface 64b of the buttock support portion 64 . Each ischial support 86 has a tapered surface 86 h positioned between an inner wall 86 c defining a through hole 86 b and the upper surface 64 b of the buttock support 64 . The ischium support portion 86 differs from the ischium support portion 66 of the cushion 61 in that it has a tapered surface 86h.

As shown in FIGS. 20 and 21, the through hole 86b in plan view is smaller than the through hole 66b of the cushion 61 described above. The shape of the through-hole 86b is similar to the through-hole 66b, for example. As an example, the shape of the through-hole 86b in plan view is an oval shape (or an elliptical shape). An inner wall 86c defining the through hole 86b connects the lower surface 61b and the tapered surface 86h to each other. The end of the inner wall 86c on the lower surface 61b side may be R-chamfered so as to be rounded. The end of the inner wall 86c on the side of the tapered surface 86h may be R-chamfered so as to be rounded.

The tapered surface 86h connects the inner wall 86c and the upper surface 64b to each other. The tapered surface 86h forms a recess recessed with respect to the upper surface 64b. The tapered surface 86h is inclined so that the diameter of the open end of the tapered surface 86h increases toward the upper surface 64b. In plan view, the area of the tapered surface 86h may be larger than the area of the through hole 86b. The tapered surface 86h may include a curved surface 86e, which is a portion chamfered so that the open end of the tapered surface 86h is rounded.

The shape of the tapered surface 86h in plan view may be similar to the shape of the ischial support portion 6 in plan view of the cushion 1 described above. As an example, the shape of the tapered surface 86h in plan view is an oval shape (or an elliptical shape). The position of the tapered surface 86h is, for example, the same as the position of the concave portion 6b of the cushion 1 described above.

In the cushion 81 , the lumbar support portion 73 has a convex sacrum support portion 91 projecting forward from the front surface 70 h of the general portion 70 . The sacrum support portion 91 has a protruding surface 91a having a curved surface that protrudes forward, and a recessed portion 91b recessed rearward from the protruding surface 91a. The sacrum support portion 91 differs from the sacrum support portion 71 of the cushion 61 in that it has a recessed portion 91b.

As shown in FIG. 22, the recessed portion 91b extends in the third direction D3 and the second direction D2. For example, the length of the recessed portion 91b in the third direction D3 is longer than the length (width) of the recessed portion 91b in the second direction D2. The shape of the recessed portion 91b when viewed from the first direction D1 may be a groove shape (or an oval shape) extending in the third direction D3. The recessed portion 91b includes a bottom surface 91c and an inner side surface 91d connecting the bottom surface 91c and the projecting surface 91a to each other. The inner side surface 91d has an annular shape surrounding the bottom surface 91c when viewed from the first direction D1. The inner side surface 91d may include an R surface connecting the bottom surface 91c and the projecting surface 91a.

As shown in FIG. 20, in a plan view, the bottom surface 91c is curved so as to be recessed rearward as the distance from the end of the recessed portion 91b in the second direction D2 increases. The curvature of the bottom surface 91c in plan view may be the same as the curvature of the projecting surface 91a in plan view.

As shown in FIG. 23 , in a cross section (side cross section) orthogonal to the second direction D2, the bottom surface 91c is curved so as to be recessed rearward as the distance from the end of the recess 91b in the third direction D3 increases. The curvature of the bottom surface 91c in the side cross section may be the same as the curvature of the projecting surface 91a in the side cross section.

The hollow portion 91b is a portion into which the user's sacrum E5 (see FIG. 6) enters. The length (width) of the recessed portion 91b in the second direction D2 is, for example, 1 cm or more and 3 cm or less. As an example, the length of the recess 91b in the second direction D2 is 2 cm. The length of the recessed portion 91b in the third direction D3 is, for example, 5 cm or more and 9 cm or less. As an example, the length of the recessed portion 91b in the third direction D3 is 7 cm. The depth of the recessed portion 91b in the first direction D1 is, for example, 0.5 cm or more and 1.5 cm or less. As an example, the depth of the recess 91b in the first direction D1 is 1 cm. However, the depth of the recessed portion 91b in the first direction D1 is not limited to the above numerical value, and may be 1.5 cm or more. Further, the recessed portion 91b may penetrate the sacrum support portion 91 in the first direction D1. Furthermore, the recessed portion 91b may penetrate the waist support portion 73 in the first direction D1.

Next, functions and effects obtained from the cushion 81 according to the fifth modified example will be described. As shown in FIG. 19, each ischial support 86 has an inner wall 86c of the through hole 86b defining the through hole 86b and a tapered surface 86h positioned between the upper surface 64b of the buttock support 64. As shown in FIG. Therefore, since the tapered surface 86h exists between the inner wall 86c of the through hole 86b and the upper surface 64b of the buttocks support portion 64, the inner wall 86c of the through hole 86b is connected to the upper surface 64b of the buttocks support portion 64 via the tapered surface 86h. connect smoothly. Therefore, when the user sits on the seat portion 62, the ischium E6 that has entered the through hole 86b can be gently supported by the tapered surface 86h, so that the force applied to the ischium E6 can be further reduced.

The sacrum support portion 91 has a protruding surface 91a protruding forward and a recessed portion 91b recessed rearward from the protruding surface 91a. Therefore, the sacrum E5 of the user can be inserted into the recessed portion 91b while supporting the sacrum E5 of the user by the projecting surface 91a. Therefore, the sacrum E5 can be supported from both sides of the recessed portion 91b, and the pressure on the sacrum E5 can be reduced.

The recessed portion 91b may extend in the third direction D3 and the second direction D2. As shown in FIG. 20, in a plan view, the bottom surface 91c may be curved so as to be recessed rearward as the distance from the end of the recessed portion 91b in the second direction D2 increases. In this case, since the bottom surface 91c is curved backward in plan view, the pressure on the sacrum E5 can be further relieved.

As shown in FIG. 23, in a cross section perpendicular to the second direction D2, the bottom surface 91c may be curved so as to be recessed rearward as the distance from the end of the recessed portion 91b in the third direction D3 increases. In this case, the pressure on the sacrum E5 can be further relieved by the concave portion 91b being curved backward in a side view.

The embodiment and the first to fifth modifications of the cushion according to the present disclosure have been described above. However, the present disclosure is not limited to the above-described embodiment or the first to fifth modifications, and may be further modified within the scope of the gist described in the claims. That is, the shape, size, number, material, and arrangement of each part of the cushion are not limited to the above-described embodiment or various modifications, and can be further modified within the scope of the above gist. For example, the cushion according to the present disclosure may be a combination of two or more of the above-described embodiment, first to fifth modifications, and various modifications described below.

For example, the embodiments and variations described above describe a cushion that includes a seat portion and a lumbar support portion. However, the height of the waist support can be changed as appropriate. For example, the height of the upper end of the waist support may be the height of the user's back, the height of the user's shoulders, or the height of the user's head. There is no particular limitation. In this case, the cushion can be used as a chair such as a gaming chair.

For example, a cushion may be used in which the lumbar support portion is foldable with respect to the seat portion. In this case, the cushion can be used as an office chair, recliner or full-flat seat. The cushion may be a seat used in a vehicle for transportation such as an automobile, rail vehicle, or aircraft.

Further, for example, a rigid support member may be provided below the seating portion. In this case, it is possible to support the user's buttocks and thighs more firmly with the seat by making it difficult for the seat to deform. A rigid support member may be provided at the rear of the waist support. In this case, the waist support part is less likely to be deformed, and the waist support part can more firmly support the waist of the user. The support member is made of, for example, a chip board or hard resin. The seat portion and the lumbar support portion may be connected to each other by the support member. Also in this case, the cushion can be used as a cushion for a chair such as an office chair.

The lumbar support and sacral support need not be integral. For example, the sacral support may be removably joined to the lumbar support. For example, the sacrum support can be attached to and detached from the lumbar support by a connecting member. In this case, the sacrum support section that is joined to the lumbar support section of one cushion via a joint member is removed, and the sacrum support section is attached to the lumbar support section of another cushion that is different from the one cushion. . In this way, it is possible to attach and detach the sacrum support to the lumbar support of various cushions. The joining member may be, for example, a hook-and-loop fastener, a hook, or a button, and the type of the joining member is not particularly limited.

In the first modified example described above, the cushion 21 made of urethane foam that has been two-dimensionally cut has been described as an example of the flexible material. For example, this cushion 21 may have a soft layer and a hard layer. For example, the cushion 21 may be configured such that the convex portions 21b and 23b are made of soft layers, and the layer below the convex portions 21b and the layer behind the waist support portion 23 are made of hard layers. In this case, the user's buttocks, thighs, back and waist can be held more firmly.

The inclination angle θ2 of the inclined surface 7 shown in FIGS. 3 and 15 may be 0° or more and less than 5°. In the cushion according to the present disclosure, the upper surface of the seating portion may be parallel to the lower surface of the seating portion. That is, the seating portion of the cushion according to the present disclosure may not have an inclined surface extending obliquely upward from the buttock support portion toward the thigh support portion.

As shown in FIGS. 18 and 21, the above-described modification includes a pair of thigh supports 65, each thigh support 65 having recesses 65d, the pair of recesses 65d spaced apart from each other. The cushions 61 and 81 provided at the positions are illustrated. However, the shape and configuration of the thigh support are not limited to the above examples. For example, the cushion may have a single recess containing a pair of thigh supports 65 . That is, a pair of thigh support portions 65 may share one recess. In this case, the pair of recesses 65d described above are connected to each other and formed as one recess.

In the modified example described above, a cushion including a ischial support portion, an inclined portion and a sacral support portion was exemplified. However, the cushion may not have a ischial support, for example a cushion with only a sacral support 91 . In this case, the sacral support portion 91 has a protruding surface 91a protruding forward and a recessed portion 91b recessed rearward from the protruding surface 91a. Therefore, the user's sacrum E5 can be inserted into the recessed portion 91b while supporting the user's sacrum E5 by the projecting surface 91a, so that the same effect as the cushion 81 described above can be obtained.

Further, the cushion may not include ramps and/or sacral supports, but may include only a pair of thigh supports 65, for example. In this case, each of the pair of thigh support portions 65 has a recess 65d recessed in the thickness direction of the cushion. Therefore, each thigh support portion 65 can be made easier to deform than portions of the seating portion other than the thigh support portion 65, so that the same effect as that of the cushion 61 described above can be obtained.

(Example)
Next, a comparative example without a cushion and examples of cushions according to each of Examples 1, 2, 3 and 4 will be described. In addition, the present invention is not limited to the examples described later. In the experiments according to the examples, the pressure distribution of the body pressure applied to the user seated on each cushion or chair was measured, and the maximum pressure and average pressure were calculated. The pressure distribution was measured by a pressure distribution measuring device manufactured by Xsensor.

The cushion according to Example 1 includes a portion corresponding to the sacrum support portion 71 of the cushion 61 as illustrated in FIG. 13 . The cushion according to Example 2 includes a portion corresponding to the sacrum support portion 91 of the cushion 81, as illustrated in FIG. That is, the cushion according to the second embodiment differs from the cushion according to the first embodiment in that it has the recessed portion 91b. The cushion according to Example 3 includes a portion corresponding to the thigh support portion 5 of the cushion 1, as illustrated in FIG. The cushion according to Example 4 includes a portion corresponding to the thigh support portion 65 of the cushion 61 as illustrated in FIG. 13 . That is, the cushion according to the fourth embodiment differs from the cushion according to the third embodiment in that it has the concave portion 65d.

FIG. 24 shows experimental results (actual measurement data) showing the pressure distribution of a comparative example in which a user sits on a chair without a cushion. In FIG. 24 and actual measurement data in FIGS. 25(a), 25(b), 26(a) and 26(b), which will be described later, the pressure distribution of the seated user is indicated by black Shown inside the background. In the pressure distribution, areas where the pressure applied to the user is large are shown in a color close to black, and areas where the pressure applied to the user is small are shown in a color close to white. FIG. 24 shows a region corresponding to the sit bone on the left side and a region corresponding to the thigh on the right side. As shown in FIG. 24, in the comparative example, the pressure distribution was high overall, and it was found that the pressure was particularly concentrated on the ischium of the user. In the comparative example of FIG. 24, the user was subjected to a maximum pressure of 167.6 mmHg and an average pressure of 45.8 mmHg.

FIG. 25(a) is an experimental result (actual measurement data) showing the pressure distribution of Example 1. FIG. In Example 1, the pressure distribution was measured when the user sat on the cushion according to Example 1. FIG. FIG. 25(b) is an experimental result (actual measurement data) showing the pressure distribution of Example 2. FIG. In Example 2, the pressure distribution was measured when the user sat on the cushion according to Example 2. FIG. 25(a) and 25(b), an area X1 corresponding to the sacrum, an area corresponding to the thigh, and an area corresponding to the ischium located between the area X1 and the area corresponding to the thigh. showing the area.

As shown in FIGS. 25(a) and 25(b), in Examples 1 and 2, compared with the comparative example in FIG. was found to be dispersed. In Example 1, the user was subjected to a maximum pressure of 95.5 mmHg and an average pressure of 38.7 mmHg. In Example 2, the user was subjected to a maximum pressure of 100.3 mmHg and an average pressure of 34.0 mmHg. From the above, it was confirmed that the cushions according to Examples 1 and 2 can disperse the pressure applied to the user's sit bones.

In Example 2, compared with Example 1, the region of high pressure was further reduced, and it was found that the pressure applied to the user's sacrum E5 was more dispersed. In the region X1 corresponding to the sacrum E5 of Example 1, the user was subjected to a maximum pressure of 95.5 mmHg and an average pressure of 42.2 mmHg. In the region X1 corresponding to the sacrum E5 in Example 2, the user was subjected to a maximum pressure of 100.3 mmHg and an average pressure of 35.6 mmHg.

In the area X2 on the central side of the area X1 corresponding to the sacrum E5 in Example 1, the user was subjected to an average pressure of 55.0 mmHg. In the area X2 on the central side of the area X1 corresponding to the sacrum E5 in Example 2, the user was subjected to an average pressure of 33.1 mmHg. From the above, it was confirmed that the cushion of Example 2, in which the sacrum support portion has a portion corresponding to the recessed portion 91b, can further disperse the pressure applied to the sacrum E5.

FIG. 26(a) is an experimental result (actual measurement data) showing the pressure distribution of Example 3. FIG. In Example 3, the pressure distribution was measured when the user sat on the cushion according to Example 3 in a forward leaning posture. FIG. 26(b) is an experimental result (actual measurement data) showing the pressure distribution of Example 4. FIG. In Example 4, the pressure distribution was measured when the user sat on the cushion according to Example 4 in a forward leaning posture. 26(a) and 26(b) show the pressure distribution in the region corresponding to the thigh.

As shown in FIGS. 26( a ) and 26 ( b ), Example 4 further reduces the areas of high pressure compared to Example 3, and reduces the pressure applied to the user's thighs. It has been found that it can be dispersed further. In Example 3, the user was subjected to a maximum pressure of 94.3 mmHg and an average pressure of 44.8 mmHg. In Example 4, the user was subjected to a maximum pressure of 83.8 mmHg and an average pressure of 41.8 mmHg. From the above, it was confirmed that the cushion of Example 4, in which the thigh supporting portion has a portion corresponding to the concave portion 65d, can more remarkably disperse the pressure applied to the thigh.

DESCRIPTION OF SYMBOLS 1... Cushion 1b... Lower surface 2... Seating part 3... Lumbar support part 3b... Front end 3c... Inclined surface 4... Buttocks support part 4b... Upper surface 4c... Bottom part 5... Thigh support part 5b... Top part 5c... Curved part 6... Ischial support part 6b... Concave part 6c... Corner part 6d... Long axis 6f... Short axis 6g... Center 6h... Curved surface 7... Inclined surface 8... Convex portion 8b... Top portion 8c... Inclined portion 9... Convex portion 9b... Top portion 9c... Inclined portion 10... General portion 10b... First portion 10c... Second portion 10d... Inner surface 10f... Outer surface , 10g... concave part, 10h... front surface, 11... sacral support part, 11b... long axis, 11c... short axis, 11d... upper end, 11g... projecting surface, 11h... center, 12... lumbar spine support part, 13... iliac support part , 21...Cushion 21b...Convex part 21c...Slit 21d...Lower surface 21f...Straight part 21g...Expansion part 22...Seating part 22b...Upper slit 22c...Straight part 22d...Expansion part 23... Lumbar support part 23b... Convex part 23c... Slit 23d... Rear surface 23f... Straight part 23g... Extended part 23h... Front slit 23j... Narrow part 23k... Extended part 24... Buttock support part 24b Upper surface 25 Thigh support part 26 Sciatica support part 27 Slit 27b Curved part 27c Extension part 28 Deformation part 29 Inclined surface 31 Sacral support part 32 Lumbar spine Supporting portion 41 Cushion 43 Lumbar supporting portion 44 Convex portion 44b Front surface 51 Cushion 52 Protruding portion 61 Cushion 61b Lower surface 62 Seating portion 62a Ventilation hole 64 ... Buttock support part 64b... Upper surface 65... Thigh support part 65d... Recessed part 65e... Top part 65f... Inclined part 66... Ischial bone support part 66b... Through hole 70... General part 70b... First part Portion 70f...Outer surface 70h...Front surface 71...Sacral support part 71a...Protruding surface 73...Lumbar support part 74...Convex part 86...Ischial bone support part 86b...Through hole 86c...Inner wall 86e...Curved surface , 86h...tapered surface, 91...sacral support part, 91a...protruding surface, 91b...indented part, 91c...bottom surface, 91d...inner surface, B...space, D1...first direction, D2...second direction, D3...third direction 3 directions, D4...longitudinal direction, D5...short axis direction, E1...spine, E2...pelvis, E3...iliac bone, E4...pubic bone, E5...sacrum, E6...sciatica, G1, G2...convex part group, L1, L2... Extension line, L3... Imaginary line, P... Intersection, S... Placement surface, X1, X2... Area, ?1... Intersection angle, ?2... Inclination angle.

Claims (13)

A cushion made of a flexible material,
a seat having a buttock support on which the user's buttocks rest and a thigh support on which the user's thighs rest;
The buttocks support part has a pair of ischium support parts arranged along the left-right direction as seen from the user seated on the seat part,
Each of the ischium support portions has a recess recessed from the upper surface of the buttock support portion in a state where the ischium is placed thereon,
the curvature of each recess is greater than the curvature of the upper surface;
The seating portion has an inclined surface extending obliquely upward from the buttock support portion toward the thigh support portion,
cushion. A cushion made of a flexible material,
a seat having a buttock support on which the user's buttocks rest and a thigh support on which the user's thighs rest;
The buttocks support part has a pair of ischium support parts arranged along the left-right direction as seen from the user seated on the seat part,
each of the ischium support portions has a through hole penetrating downward from the upper surface of the buttock support portion;
The seating portion has an inclined surface extending obliquely upward from the buttock support portion toward the thigh support portion,
cushion. each ischial support portion has a tapered surface located between an inner wall of the through hole defining the through hole and an upper surface of the buttock support portion;
3. A cushion according to claim 2. A waist support part that contacts the user's waist from behind,
The lumbar support has a convex sacral support that supports the user's sacrum from behind.
The cushion according to any one of claims 1-3. the sacral support has a projecting surface,
The protruding surface has a curved surface shape protruding forward,
5. A cushion according to claim 4. The lumbar support has a lumbar support that supports the user's lumbar spine from behind above the sacrum support.
6. A cushion according to claim 4 or 5. The lumbar support section has an ilium support section that supports the ilium of the user on both left and right sides of the lumbar support section as viewed from the user seated on the seating section.
7. A cushion according to claim 6. The shape of each ischial bone support portion in a plan view is such that it extends in a long axis direction and a short axis direction that intersects with the long axis direction, and the length in the long axis direction is longer than the length in the short axis direction. and
extension lines of the pair of long axes of the pair of ischium support portions intersect each other at a position closer to the thigh support portion than the pair of ischium support portions;
A cushion according to any one of claims 1-7. The angle of intersection of the extension lines of the pair of long axes is 40° or more and 150° or less.
9. A cushion according to claim 8. The thickness of the thigh support portion when the user sits on the seating portion is the thickness of the portion of the seating portion other than the thigh support portion when the user sits on the seating portion. thinner than
A cushion according to any one of claims 1-9. The amount of deformation of the thigh support portion when the user sits on the seating portion is the amount of deformation of the portion of the seating portion other than the thigh support portion when the user sits on the seating portion. greater than the quantity
A cushion according to any one of claims 1-10. The thigh support has a recess that defines a space between it and a mounting surface on which the cushion is mounted.
12. A cushion according to claim 10 or 11. The projected area of the lower surface of the cushion is smaller than the projected area of the cushion in plan view,
A cushion according to any one of claims 1-12.

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