cushion

Abstract

To provide a cushion capable of improving sitting comfort.SOLUTION: A cushion according to an embodiment is a cushion 61 constituted of a flexible raw material. The cushion 61 includes a seat part 62 having a hip support part 64 where a user's hip is placed, and a pair of thigh support parts 65 where each of a pair of thighs of the user is placed. Each thigh support part has a recess 65d hollowed in the thickness direction of the cushion 61. The depth of the recess 65d becomes deeper as separating from the hip support part 64.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present disclosure relates to a cushion on which a user's buttocks and thighs are placed.

Background Art

[0002] Conventionally, various cushions on which a user's buttocks and thighs are placed are known. Japanese Patent Application Laid-Open No. 2014-12130 describes a chair cushion. The chair cushion includes a cushion body and a cover. The cushion body includes a seat portion against which the buttocks of the seated person abut and a back portion against which the back of the seated person abuts. The two parts corresponding to the ischial bones with respect to the seat portion in a side view have a concave surface shape.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above-described chair cushion has two parts corresponding to the ischial bones having a concave surface shape. In this chair cushion, the ischial bones of the user of the chair cushion fit into each part corresponding to the ischial bone. However, when the ischial bones fit into such a concave portion, the thighs located in front of the user's ischial bones may be relatively positioned upward. Therefore, since the thighs may be relatively positioned upward with respect to the buttocks, it may cause discomfort to the user. Therefore, there is room for improvement in terms of the sitting comfort on the cushion.

[0005] An object of the present disclosure is to provide a cushion that can improve sitting comfort.

Means for Solving the Problems

[0006] The cushion relating to this disclosure is a cushion made of a flexible material. The cushion comprises a seating portion having a buttock support portion on which the user's buttocks rest, and a pair of thigh support portions on which each of the user's thighs rest. Each thigh support portion has a recess that is indented in the thickness direction of the cushion. The depth of the recess increases as it moves away from the buttock support portion. The seating portion has an inclined surface that extends diagonally upward from the buttock support portion toward the thigh support portion. The thigh support portion includes a top portion located at the front end of the inclined surface and the front end of the cushion, and an inclined portion extending posteriorly and diagonally downward from the top portion toward the lower surface of the cushion.

[0007] This cushion has a seating section, which has a buttock support section and a pair of thigh support sections. Since this cushion is made of a flexible material, it can gently support the user's buttocks supported by the buttock support section and the pair of thigh support sections. Each of the pair of thigh support sections has a recess that curves in the thickness direction of the cushion. Therefore, each thigh support section can be deformed more easily than the other parts of the seating section. Consequently, when the thighs are placed on the thigh support sections, the thigh support sections can be moved more easily downwards, making it more difficult for the thighs to rise and reducing discomfort for the user. The depth of the recess in each thigh support section increases with distance from the buttock support section. That is, the depth of the recess in each thigh support section increases towards the front when viewed from the perspective of a user seated on the seating section. Therefore, the front part of the thigh support section can be deformed more easily downwards compared to the buttock support section, thus more effectively preventing the thighs from rising. Therefore, it is possible to reduce discomfort for the user and improve the sitting comfort of the cushion.

[0008] The thickness of the thigh support portion when the user is seated on the seat may be thinner than the thickness of the other parts of the seat when the user is seated on the seat. In this case, since the thigh support portion is thinner than the other parts of the seat when the user is seated on the seat, it becomes more difficult for the user's thighs to rise. Therefore, the seating comfort can be improved.

[0009] The amount of deformation of the thigh support when a user sits on the seat may be greater than the amount of deformation of the parts of the seat other than the thigh support when a user sits on the seat. In this case, when a user sits on the seat, the amount of downward deformation of the thigh support is greater than that of the parts of the seat other than the thigh support, making it more difficult for the user's thighs to rise. Therefore, as described above, the sitting comfort can be improved.

[0010] The aforementioned recess may be formed on the underside of the cushion. In this case, the recess defines a space between the cushion and the surface on which it is placed. Therefore, when the user's thighs are placed on the thigh support, the thigh support easily deforms so that the space decreases. Consequently, the thigh support can be deformed more easily downwards, which suppresses the thighs from rising and further improves sitting comfort.

[0011] large Since the height of the buttock support is lower than the height of the thigh support, it is possible to prevent the buttocks from sliding forward, and thus suppress the forward movement of the ischial tuberosities. Consequently, the force on the ischial tuberosities can be reduced, and the movement of the ischial tuberosities can be suppressed. [Effects of the Invention]

[0012] According to this disclosure, it is possible to improve seating comfort. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view showing a cushion according to an embodiment. [Figure 2] This is a plan view showing a cushion according to an embodiment. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4] This is a front view showing a cushion according to an embodiment. [Figure 5] Figure 2 is a cross-sectional view along line BB. [Figure 6]It is a diagram schematically showing the backbone and pelvis of the body. [Figure 7] (a) is a diagram schematically showing the pelvis of the body. (b) is a diagram schematically showing the backbone and pelvis of the body. [Figure 8] (a) is a graph showing the position of the sitting bone of the user in a plan view. (b) is a graph showing the height position of the sacrum of the user. [Figure 9] It is a side view showing the cushion according to the first modification example. [Figure 10] (a) is a front view of the seating part of the cushion according to the first modification example. (b) is a plan view of the lumbar support part of the cushion according to the first modification example. [Figure 11] It is a plan view of the seating part according to the first modification example. [Figure 12] (a) is a perspective view showing the cushion according to the second modification example. (b) is a perspective view showing the cushion according to the third modification example. [Figure 13] It is a perspective view showing the cushion according to the fourth modification example. [Figure 14] It is a plan view showing the cushion according to the fourth modification example. [Figure 15] It is a cross-sectional view taken along line C-C of FIG. 14. [Figure 16] It is a front view showing the cushion according to the fourth modification example. [Figure 17] It is a cross-sectional view taken along line D-D of FIG. 可见,在一些实施例中,用户可以通过触摸屏幕上的特定区域来触发特定的操作。例如,用户可以触摸屏幕上的“开始”按钮来启动应用程序,或者触摸“设置”图标来访问设置菜单。 [Figure 18] It is a bottom view showing the cushion according to the fourth modification example. [Figure 19] It is a perspective view showing the cushion according to the fifth modification example. [Figure 20] It is a plan view showing the cushion according to the fifth modification example. [[ID=插空行]] [Figure 21] It is a bottom view showing the cushion according to the fifth modification example. [Figure 22] It is a front view showing the cushion according to the fifth modification example. [Figure 23] It is a cross-sectional view taken along line E-E of FIG. 20. [Figure 24]This is an experimental result (measured data) showing the pressure distribution for a comparative example, which is an example of a user sitting on a chair without a cushion. [Figure 25] (a) is experimental results (measured data) showing the pressure distribution at the seating area and sacral support area when a user sits on the cushion according to Example 1. (b) is experimental results (measured data) showing the pressure distribution at the seating area and sacral support area when a user sits on the cushion according to Example 2. [Figure 26] (a) is experimental results (measured data) showing the pressure distribution at the thigh support area when a user sits in a forward-leaning posture on the cushion according to Example 3. (b) is experimental results (measured data) showing the pressure distribution at the thigh support area when a user sits in a forward-leaning posture on the cushion according to Example 4. [Modes for carrying out the invention]

[0014] The embodiments of the cushions relating to this disclosure will be described below with reference to the drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. In addition, for the sake of ease of understanding, some parts of the drawings may be simplified or exaggerated, and the dimensional ratios, etc., are not limited to those shown in the drawings.

[0015] The cushion relating to this disclosure is made of a flexible material. "Flexible material" refers to a cushioning material that deforms when a body is placed on it and subjected to a load. The cushion comprises a seating section having a buttock support section on which the user's buttocks rest, and a thigh support section on which the user's thighs rest.

[0016] "User" refers to the person using the cushion, for example, the person sitting on the cushion. "Buttocks" refers to the rounded lower part of the back, the part of the body located below the waist and above the thighs. "Thighs" refers to the thigh area from the hip to the knee.

[0017] "Sitting" refers to sitting on the cushion. The "seat portion" refers to the part of the cushion that the buttocks and thighs come into contact with when sitting on it. The buttock support portion has a pair of ischial support portions. The "ischial tuberosity" refers to the lowest part of the pelvis when the user is seated on the seat portion.

[0018] Figure 1 is a perspective view showing the cushion 1 according to this embodiment. As shown in Figure 1, the cushion 1 comprises a seating portion 2 extending horizontally and a lumbar support portion 3 extending upward from the seating portion 2. The cushion 1 is made of a flexible material. For example, the cushion 1 is made of foamed urethane.

[0019] For example, cushion 1 is formed by urethane molding. When cushion 1 is made of foamed urethane and formed by urethane molding, cushion 1 made of a flexible material can be easily manufactured. Cushion 1 is, for example, a core material used in conjunction with a fabric cover.

[0020] The flexible material mentioned above includes, for example, a thermoplastic elastomer. The flexible material may also be a material with elasticity that deforms in response to the load when a body is placed on it. The flexible material may also be a resin (for example, polypropylene, polyester, or polyethylene) that deforms when a body is placed on it and subjected to a load. The flexible material may also be a mesh material. Thus, the type of flexible material can be changed as appropriate.

[0021] The seating portion 2 extends in a first direction D1 and a second direction D2 that intersects the first direction D1. The first direction D1 is the front-to-back direction as viewed from the user seated on the seating portion 2, and the second direction D2 is the left-to-right direction as viewed from the user seated on the seating portion 2. The seating portion 2 has 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.

[0022] In the following, the direction forward as viewed from the user seated on seat 2 may be referred to as "front," "front side," or "forward," and the opposite direction may be referred to as "rear," "rear side," or "backward." However, these directions are for illustrative purposes only and do not limit the position or orientation of each part.

[0023] Figure 2 is a plan view of cushion 1. As shown in Figures 1 and 2, the length A1 of cushion 1 in the first direction D1 is 30 cm or more and 90 cm or less. Length A1 may also be 40 cm or more and 50 cm or less, for example, 45 cm. The length A2 of cushion 1 in the second direction D2 is similar to length A1, being 30 cm or more and 90 cm or less, or 40 cm or more and 50 cm or less, for example, 45 cm.

[0024] The seating section 2 has a buttock support section 4 on which the user's buttocks rest and a thigh support section 5 on which the user's thighs rest. The buttock support section 4 and the thigh support section 5 are arranged to be aligned along a first direction D1. The buttock support section 4 has a pair of ischial support sections 6 that support the ischial tuberosities of the user when seated on the seating section 2.

[0025] The ischial support portion 6 is formed on the upper surface 4b of the buttock support portion 4 and is recessed relative to the upper surface 4b. Figure 3 is a cross-sectional view taken along line AA in Figure 2. As shown in Figures 2 and 3, the buttock support portion 4 has a pair of ischial support portions 6 aligned along the second direction D2. The ischial support portion 6 has a recess 6b that is recessed from the upper surface 4b of the buttock support portion 4. The recess 6b is defined, for example, by a corner portion 6c which is the boundary with the upper surface 4b and a curved surface 6h located inside the corner portion 6c in a plan view. The curvature of the recess 6b (curved surface 6h) is greater than the curvature of the upper surface 4b of the buttock support portion 4. The recess 6b does not have to be exposed. The recess 6b only needs to be recessed from the upper surface 4b of the buttock support portion 4 when the user's ischial bones are placed on it. For example, the recess 6b may be filled with a material that is more easily recessed than the buttock support portion 4.

[0026] The shape of the ischial support portion 6 in plan view is such that it has a major axis 6d and a minor axis 6f. That is, the ischial support portion 6 extends in both the major axis direction D4, which is the direction in which the major axis 6d extends, and the minor axis direction D5, which is the direction in which the minor axis 6f extends. For example, the shape of the ischial support portion 6 in plan view is oval. As another example, the shape of the ischial support portion 6 in plan view is elliptical. However, the shape of the ischial support portion 6 in plan view is not limited to oval or elliptical, but may also be rectangular, rounded rectangular, rhombus, or rounded rhombus, and can be changed as appropriate.

[0027] The extension line L1 of the long axis 6d of one of the pair of ischial support parts 6 intersects with the extension line L2 of the long axis 6d of the other ischial support part 6. The intersection angle θ1 between extension lines L1 and L2 is, for example, 40° or more and 150° or less. The intersection angle θ1 may also be 50° or more, 60° or more, 75° or more, or 90° or more. Alternatively, 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°.

[0028] The intersection point P of extension line L1 and extension line L2 is located closer to the thigh support part 5 than to the pair of ischial support parts 6. The intersection point P is located closer to the thigh support part 5 than to the center 6g of each ischial support part 6 in a plan view. The intersection point P is located on the opposite side from the lumbar support part 3 when viewed from the pair of ischial support parts 6. As a result, the pair of ischial support parts 6 exhibit an inverted V shape in a plan view (a plan view when the lumbar support part 3 is positioned above the seating part 2).

[0029] The length of the long axis 6d of the ischial support portion 6 is, for example, 5 cm or more and 10 cm or less. For example, the length of the long axis 6d is 7 cm. The length of the short axis 6f of the ischial support portion 6 is, for example, 3 cm or more and 9 cm or less. For example, the length of the short axis 6f is 5 cm.

[0030] The distance A5 between the centers 6g of a pair of ischial support parts 6 (distance between the centers of a pair of ischial support parts 6) is, for example, 7 cm or more and 15 cm or less. For example, distance A5 is 10 cm. The positions of the pair of centers 6g in the first direction D1 are, for example, identical. The distance from the lumbar support part 3 to the center 6g is, for example, 5 cm or more and 15 cm or less. For example, the distance from the lumbar support part 3 to the center 6g is 10 cm. When each length and each distance is within the above range, the user's ischial bones can be more suitably fitted to each of the pair of ischial support parts 6.

[0031] The seating portion 2 has an inclined surface 7 that extends diagonally upward from the buttock support portion 4 toward the thigh support portion 5. For example, the seating portion 2 has a pair of inclined surfaces 7 aligned along the second direction D2. For example, in a cross-section along a plane extending in the first direction D1 and the third direction D3, the inclined surfaces 7 are linear. 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 inclination angle θ2 is 10°.

[0032] When the inclination angle θ2 is 5° or more and 15° or less, the ischial tuberosities of the user seated on the seating portion 2 can be made even less likely to slide forward. In contrast to the above example, the inclined surface 7 may be curved in cross-section along the planes extending in the first direction D1 and the third direction D3 (for example, a curved shape that curves so that the inclination angle θ2 increases as it approaches the thigh support portion 5).

[0033] For example, the seating portion 2 has a pair of thigh support portions 5 aligned 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 located on the front side of the inclined surface 7. For example, the thigh support portions 5 are convex in shape. The back of the user's thighs rests on the thigh support portions 5. That is, the thigh support portions 5 support the back of the user's thighs. 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 diagonally downward from the top portion 5b.

[0034] The protrusion 8 represents a portion that extends from the inclined surface 7. For example, in a plan view, the protrusion 8 has a shape that extends along the first direction D1. In a plan view, the width of the protrusion 8 increases as it extends forward. The height of the protrusion 8 increases as it moves towards the center in the second direction D2.

[0035] The convex portion 8 has a vertex 8b and an inclined portion 8c that extends forward and diagonally downward from the vertex 8b. In a plan view, the shape of the inclined portion 8c is, for example, a triangular shape that widens as it extends forward. The position of the vertex 8b of the convex portion 8 is located behind the position of the vertex 5b of the thigh support portion 5.

[0036] Figure 4 is a front view of cushion 1 as seen from the front. As shown in Figures 2 to 4, the seating portion 2 has a pair of protrusions 9 located at both ends in the second direction D2 on the inclined surface 7. For example, the protrusions 9 connect the lumbar support portion 3 and the thigh support portion 5 to each other. The protrusions 9 extend along the first direction D1.

[0037] The top 9b of the protrusion 9 is, for example, a curved surface. For example, the height of the top 9b of the protrusion 9 is higher than the height of the top 5b of the thigh support portion 5. The height of the top 9b of the protrusion 9 may be the same as the height of the top 8b of the protrusion 8. By providing the above-described protrusions 8 and 9, it becomes easier to place the user's thighs on each of the positions on both sides of the protrusion 8 in the second direction D2 between the pair of protrusions 9. Note that the shape of the protrusions 8 and 9 is not limited to the above-described embodiment and can be changed as appropriate. Furthermore, the cushion may not have at least one of the protrusions 8 and 9.

[0038] Next, the lumbar support portion 3 will be described. For example, the lumbar support portion 3 is curved so as it protrudes forward towards both ends in the second direction D2. Figure 5 is a cross-sectional view along line BB in Figure 2. As shown in Figures 3 to 5, the lumbar support portion 3 extends upward from the end (rear end) of the seating portion 2 in the first direction D1.

[0039] The lumbar support portion 3 includes, for example, a general portion 10 extending in both the second direction D2 and the third direction D3, and a sacral support portion 11 located in the center of the second direction D2 at the lower part of the general portion 10. The general portion 10 represents the portion of the lumbar support portion 3 other than the sacral support portion 11. The general portion 10 includes a first portion 10b extending upward from the rear end of the buttock support portion 4, and a second portion 10c extending upward and diagonally forward from the upper end of the first portion 10b.

[0040] The thickness of the first portion 10b in the first direction D1 decreases as it extends upward. The first portion 10b is composed of an inner surface 10d that curves backward and diagonally upward, and an outer surface 10f that curves outward in the first direction D1. The first portion 10b also has recesses 10g at each end in the second direction D2 that are recessed along the second direction D2.

[0041] The second part 10c is located, for example, above the first part 10b and the sacral support part 11. The second part 10c has a lumbar support part 12 that supports the user's lumbar spine from the rear, and iliac support parts 13 that support the user's ilium on both sides of the lumbar support part 12 in a second direction D2. For example, a pair of iliac support parts 13 are provided on both sides of the lumbar support part 12 in a second direction D2.

[0042] For example, the lumbar support portion 12 is defined by an anterior end 3b located above the lumbar support portion 3 and an inclined surface 3c extending diagonally downward from the anterior end 3b. Each of the pair of iliac support portions 13 protrudes both ends in the second direction D2 and also protrudes forward. The lumbar support portion 12 supports the lumbar vertebrae by contacting the user's lumbar vertebrae from the rear. The iliac support portions 13 support the pair of iliac bones by facing the user's iliac bones from both ends in the second direction D2.

[0043] For example, the sacral support portion 11 has a convex shape that protrudes forward. The sacral support portion 11 protrudes forward from the front surface 10h of the general portion 10. As an example, the shape of the sacral support portion 11 when viewed from the front has a shape having a long axis 11b and a short axis 11c. For example, the shape of the sacral support portion 11 when viewed from the front is oval. As an example, the shape of the sacral support portion 11 when viewed from the front is elliptical.

[0044] However, the shape of the sacral support portion 11 as viewed from the front may be other than an oval or elliptical shape, for example, it may be rectangular, a rounded rectangular, a rhombus, or a rounded rhombus, and can be changed as appropriate. For example, the upper end 11d of the protruding surface 11g of the sacral support portion 11 is flush with the front surface 10h of the general portion 10. The protruding surface 11g of the sacral support portion 11 protrudes forward on the inner surface 10d of the general portion 10. The protruding surface 11g is inclined forward as it extends upward, for example. As an example, the protruding surface 11g is flat.

[0045] The length of the long axis 11b of the sacral support portion 11 is, for example, 5 cm or more and 15 cm or less. For example, the length of the long axis 11b is 10 cm. The length of the short axis 11c of the sacral support portion 11 is, for example, 3 cm or more and 10 cm or less. For example, the length of the short axis 11c is 7 cm. In addition, the height D3 of the center 11h of the sacral support portion 11 in the third direction relative to the bottom 4c of the buttock support portion 4 is, for example, 5 cm or more and 15 cm or less. For example, the height of the center 11h is 9 cm or more and 10 cm or less. The sacral support portion 11 can be supported by the sacral support portion 11 by contacting the user's sacrum.

[0046] Incidentally, when a person sits on a cushion, it is desirable that the pelvis be horizontal in the left-right direction and that the pelvis be upright. Figure 6 is a schematic diagram showing the human spine E1 and pelvis E2. Figure 7(a) is a schematic diagram showing the pelvis E2. Figure 7(b) is a schematic diagram showing the spine E1 and pelvis E2 as viewed from the left-right direction of the body.

[0047] As shown in Figures 6, 7(a), and 7(b), in a person sitting on a cushion, it is desirable that the imaginary line L3, which is a straight line connecting the protrusion of the ilium E3 and the pubic bone E4, extends vertically. If the imaginary line L3 remains tilted for a long period of time, the person may experience problems such as fatigue, poor posture, and a tendency to gain weight (especially in the lower body).

[0048] Furthermore, from the standpoint of maintaining good posture, it is desirable to support the posterior end of the sacrum E5 and the lower ends of each of the pair of ischial tuberosities E6 so as not to shift. Specifically, by suppressing the forward displacement of the lower ends of each ischial tuberosity E6 and the downward displacement of the sacrum E5, it is possible to maintain good posture and suppress the aforementioned problems even when sitting for long periods of time.

[0049] Next, the effects and benefits obtained from the cushion 1 according to this embodiment will be described in detail. As shown in Figures 1 and 2, the cushion 1 includes a seating portion 2, and the seating portion 2 has a buttock support portion 4 and a thigh support portion 5. Since the cushion 1 is made of a flexible material, it can gently support the user's buttocks supported by the buttock support portion 4 and the user's thighs supported by the thigh support portion 5.

[0050] The buttock support section 4 has a pair of ischial support sections 6 aligned along the second direction D2 (left-right direction), and each of the pair of ischial support sections 6 has a recess 6b that is recessed from the upper surface 4b of the buttock support section 4. Therefore, when the user sits on the seating section 2, the ischial tuberosities E6 of the user's buttocks fit into each recess 6b, thereby suppressing displacement of the ischial tuberosities E6 and reducing the force acting on the ischial tuberosities E6. The curvature of each recess 6b is greater than the curvature of the upper surface 4b of the buttock support section 4. Therefore, the user's ischial tuberosities E6 can be securely fitted into the recess 6b with greater curvature, thus more reliably suppressing displacement of the ischial tuberosities E6 when sitting.

[0051] Furthermore, the seating portion 2 has an inclined surface 7 that extends diagonally upward from the buttock support portion 4 toward the thigh support portion 5. Therefore, since the height of the buttock support portion 4 is lower than the height of the thigh support portion 5, the buttocks are less likely to slide forward, and the forward movement of the ischial tuberosity E6 can be suppressed more reliably. Thus, the force on the ischial tuberosity E6 can be reduced, and the movement of the ischial tuberosity E6 can be suppressed.

[0052] The cushion 1 according to this embodiment includes a lumbar support portion 3 that contacts the user's lower back from behind. The lumbar support portion 3 has a convex sacral support portion 11 that supports the user's sacrum E5 from behind. Therefore, the lumbar support portion 3 contacts the user's lower back when the user is seated on the seating portion 2. At this time, the convex sacral support portion 11 contacts the user's sacrum E5 from behind, which prevents the user's pelvis E2 from shifting downward. Thus, the user's posture can be properly maintained.

[0053] In a plan view, the shape of each ischial support portion 6 is such that it extends in the long axis direction D4 and in the short axis direction D5 intersecting the long axis direction D4, and the length of the long axis 6d extending in the long axis direction D4 is longer than the length of the short axis 6f extending in the short axis direction D5. The extensions L1 and L2 of the pair of long axes 6d of the pair of ischial support portions 6 intersect each other at a position closer to the thigh support portion 5 than the center 6g of the pair of ischial support portions 6. Therefore, in a plan view, the pair of ischial support portions 6 exhibit an inverted V shape. In addition, the ischial bones E6 of the user sitting on the seating portion 2 exhibit an inverted V shape in a plan view. Therefore, by matching the shape of the pair of ischial support portions 6 to the shape of the user's ischial bones E6, it is possible to improve the fit of the ischial bones E6 to the ischial support portions 6 while reliably suppressing the slippage of the ischial bones E6.

[0054] In this embodiment, the intersection angle θ1 of the extensions L1 and L2 of the pair of major axes 6d is 40° or more and 150° or less. Therefore, it is possible to align the orientation of the major axis 6d of the ischial support part 6 with the orientation of the ischial bones E6 of the user sitting on the seating part 2, thereby further improving the fit of the ischial bones E6 to the ischial support part 6.

[0055] The lumbar support section 3 has a lumbar support section 12 that supports the user's lumbar spine from behind, above the sacral support section 11. Therefore, the lumbar spine located above the sacrum E5 is supported by the lumbar support section 12. Consequently, the lumbar spine of the user sitting on the seating section 2 is supported, and the displacement of the pelvis E2 can be suppressed more reliably.

[0056] The lumbar support section 3 has iliac crest support sections 13 that support the user's ilium E3 on both sides (left and right) of the lumbar support section 12 in the second direction D2 as viewed from the user seated on the seating section 2. Therefore, a pair of ilium E3 located on each side of the lumbar spine are supported by the iliac crest support sections 13. Consequently, displacement of the user's pelvis E2 while seated on the seating section 2 can be suppressed more reliably.

[0057] Figure 8(a) is a graph showing the position of the pair of ischial tuberosities E6 in a person in a plan view. Figure 8(b) is a graph showing the position of the sacrum E5 (position of the posteriorly protruding part of the sacrum E5) when viewed from the front. Figures 8(a) and 8(b) each show the results of measurements taken for 10 subjects.

[0058] Figure 8(a) shows the position of the ischial tuberosity E6 when sitting on a square cushion with sides of 40 cm. In the graph in Figure 8(a), the center of the cushion is considered the origin. The back of the cushion (the side that touches the subject's back) is located at +20 cm on the vertical axis of Figure 8(a), and the lower part of the vertical axis indicates the front. The horizontal axis of Figure 8(a) indicates the left-right direction.

[0059] As shown in Figure 8(a), the distance between the pair of ischial tuberosities E6 was 10cm to 11cm. Specifically, the average value for female subjects was 10.9cm, and the average value for male subjects was 10.2cm. In addition, the average distance from the back of the cushion (the side that touches the subject's back) to the ischial tuberosities in a plan view was 9.5cm for women and 8.4cm for men.

[0060] As mentioned above, in cushion 1, the distance between the centers 6g of the pair of ischial support parts 6 is 7 cm or more and 15 cm or less, and the distance from the lumbar support part 3 to the center 6g is 5 cm or more and 15 cm or less. In this case, the position and the distance between the centers of the ischial support parts 6 can be aligned with the position of the subject's ischial bones E6 in a plan view as described above, so that the position of the subject's ischial bones E6 can be fitted to the position of the ischial support parts 6. Therefore, displacement of the ischial bones E6 can be suppressed more reliably.

[0061] Figure 8(b) is a graph showing the height of the sacrum E5 relative to the bottom 4c of the buttock support 4 of a subject seated on the seating section 2 (the height of the most posteriorly protruding part of the sacrum E5). The horizontal axis of Figure 8(b) represents the second direction D2, and the vertical axis of Figure 8(b) represents the third direction D3. As shown in Figure 8(b), the height of the sacrum E5 was between 6 cm and 13.5 cm. The average height of the sacrum E5 for female subjects was 8.8 cm, and the average height of the sacrum E5 for male subjects was 9.4 cm.

[0062] In cushion 1, the height of the center 11h of the sacral support portion 11 relative to the base 4c is 5 cm or more and 15 cm or less. In this case, the height position of the sacral support portion 11 can be aligned with the height position of the sacrum E5 as described above, so that the position of the subject's sacrum E5 can be fitted to the position of the sacral support portion 11. Therefore, the position of the sacrum E5 can be fitted to the position of the sacral support portion 11 more reliably. As a result, displacement of the sacrum E5 can be suppressed more reliably.

[0063] Next, the cushion 21 relating to the first modified example will be described. Figure 9 is a side view of the cushion 21 as seen from the second direction D2. Some of the components of the cushion 21 are the same as some of the components of the cushion 1 described above. Therefore, in the following description, explanations that overlap with the components of the cushion 1 will be omitted as appropriate.

[0064] The cushion 21 is made of, for example, foamed urethane. As an example, the cushion 21 is manufactured by two-dimensional cutting. The cushion 21 has a plurality of protrusions 21b formed on the surface that comes into contact with the user's body, and a plurality of slits 21c formed on the surface opposite to the surface that comes into contact with the user's body.

[0065] The cushion 21 comprises a seating portion 22 and a lumbar support portion 23. The seating portion 22 has a buttock support portion 24 on which the user's buttocks rest and a thigh support portion 25 on which the user's thighs rest. The seating portion 22 has an inclined surface 29 that extends diagonally upward from the buttock support portion 24 toward the thigh support portion 25.

[0066] The seating portion 22 has a plurality of protrusions 21b aligned along both the first direction D1 and the second direction D2, and in a plan view, the plurality of protrusions 21b are arranged in a grid pattern. The inclined surface 29 is a virtual surface containing the plurality of protrusions 21b, and the height of the inclined surface 29 increases from the buttock support portion 24 toward the thigh support portion 25.

[0067] The height of the protrusion 21b gradually increases from the buttock support portion 24 toward the thigh support portion 25. Each of the multiple slits 21c extends along the second direction D2. The slit 21c has a straight portion 21f extending upward from the lower surface 21d of the cushion 21 and an expanded portion 21g that expands at the upper end of the straight portion 21f.

[0068] Figure 10(a) is a front view of the seating portion 22 as seen from the front. As shown in Figure 10(a), the seating portion 22 has a pair of thigh support portions 25 aligned along a second direction D2. Each of the pair of thigh support portions 25 is formed by a plurality of protrusions 21b. The height of the protrusions 21b in each thigh support portion 25 is lower than the height of the protrusions 21b located between the pair of thigh support portions 25 and at both ends of the pair of thigh support portions 25 in the second direction D2. The shape of the thigh support portion 25 as seen from the front is concave, recessed compared to other parts. This allows for a good fit of the user's thighs to each thigh support portion 25.

[0069] The seating portion 22 has, for example, a plurality of upper slits 22b that extend along a first direction D1 and are aligned along a second direction D2. The upper slits 22b have, for example, a straight portion 22c that extends downward from between a pair of protrusions 21b and an expanded portion 22d that expands at the lower end of the straight portion 22c.

[0070] For example, between a pair of upper slits 22b aligned along the second direction D2, a plurality of protrusions 21b are arranged along the second direction D2. The plurality of protrusions 21b constitute, for example, a group of protrusions G1 consisting of a plurality of protrusions 21b aligned along the second direction D2. The seating portion 22 has, for example, a plurality of protrusion groups G1.

[0071] This allows multiple groups of protrusions G1 to be deformed independently of each other, and each protrusion 21b deforms to match the shape of the user's thigh, etc., thereby improving the pressure distribution on the user's thigh, etc. As an example, three protrusions 21b are arranged between a pair of upper slits 22b. Alternatively, an upper slit extending in the second direction D2 may be formed in place of, or together with, the upper slits 22b.

[0072] Figure 10(b) is a plan view showing the lumbar support portion 23. As shown in Figures 9, 10(a), and 10(b), the lumbar support portion 23 has a plurality of protrusions 23b facing forward and a plurality of slits 23c facing away from the plurality of protrusions 23b. The plurality of protrusions 23b are arranged in a grid pattern on the front surface of the lumbar support portion 23, for example.

[0073] The multiple protrusions 23b are arranged so as to be aligned along the second direction D2 and the third direction D3, respectively. The protrusion 23b located in the center of both the second direction D2 and the third direction D3 is the tallest, and the height of the protrusions 23b decreases as you move away from this protrusion 23b. In other words, the multiple protrusions 23b as a whole form a square pyramidal shape.

[0074] Multiple slits 23c are arranged to line up along a third direction D3, and each slit 23c extends linearly, for example, along a second direction D2. Each 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 that expands at the front end of the linear portion 23f.

[0075] The lumbar support portion 23 has a sacral support portion 31 that protrudes forward. The sacral support portion 31 is formed by a plurality of protrusions 23b. The amount of protrusion of the protrusions 23b in the sacral support portion 31 is greater than the amount of protrusion of the protrusions 23b located above and below the sacral support portion 31. When viewed along the second direction D2, the shape of the sacral support portion 31 is convex, protruding more than other parts. That is, the sacral support portion 31 is composed of the highest (most protruding) protrusion 23b. This allows the user's sacrum E5 to be supported more reliably by the sacral support portion 31.

[0076] The lumbar support section 23 has a lumbar support section 32 that supports the user's lumbar spine from the rear. The lumbar support section 32 is formed by a protrusion 23b that projects forward. The lumbar support section 32 is composed of, for example, a plurality of protrusions 23b that are aligned along the second direction D2 at the upper end of the lumbar support section 23.

[0077] The lumbar support portion 23 has, for example, a plurality of front slits 23h that extend along a third direction D3 and are aligned along a second direction D2. The front slits 23h have, for example, a narrow portion 23j that extends rearward from between a pair of protrusions 23b and whose width narrows as it moves towards the rear, and an expanding portion 23k that expands at the rear end of the narrow portion 23j.

[0078] For example, between a pair of front slits 23h aligned along the second direction D2, there are multiple protrusions 23b aligned along the second direction D2. The multiple protrusions 23b have, for example, a group G2 of protrusions 23b aligned along the second direction D2. The waist support portion 23 constitutes, for example, the group G2 of multiple protrusions.

[0079] This allows multiple groups of protrusions G2 to be deformed independently of each other, and each protrusion 23b deforms to conform to the shape of the user's back or waist, thereby improving pressure distribution on the user's back and waist. As an example, three protrusions 23b are arranged between a pair of front slits 23h. Alternatively, a front slit extending in the second direction D2 may be formed instead of, or together with, the front slits 23h.

[0080] Figure 11 is a schematic plan view of the seating portion 22. For ease of understanding, the convex portion 21b is omitted from the illustration in Figure 11. As shown in Figure 11, the buttock support portion 24 has a pair of ischial support portions 26 arranged along the second direction D2. The ischial support portions 26 are formed on the upper surface 24b of the buttock support portion 24 and are formed in a slit shape on the upper surface 24b.

[0081] The ischial support portion 26 has a slit 27 that is recessed relative to the upper surface 24b. Due to the presence of the slit 27, the ischial support portion 26 is more prone to recession compared to other parts of the buttock support portion 24. The amount of deformation of the ischial support portion 26 is greater than the amount of deformation of other parts of the buttock support portion 24, so the curvature of the ischial support portion 26 when recessed is greater than the curvature of the upper surface 24b.

[0082] For example, in a plan view, the ischial support portion 26 has an oval shape. The overall shape and position of the ischial support portion 26 in a plan view are the same as, for example, the shape and position of the ischial support portion 6 in a plan view. The ischial support portion 26 has a plurality of slits 27 extending in directions inclined in both the first direction D1 and the second direction D2, and a deformable portion 28 located between the plurality of slits 27. Because the deformable portion 28 is located between the plurality of slits 27, it is a part that is more easily deformed compared to the parts of the buttock support portion 24 other than the deformable portion 28.

[0083] For example, the slit 27 penetrates the seating portion 22 in a third direction D3. The ischial support portion 26 has, for example, a pair of slits 27. The pair of slits 27 extend parallel to each other. As an example, the slit 27 has a curved portion 27b that curves in a wave shape and an expanded portion 27c that expands at each end of the curved portion 27b. The expanded portion 27c expands in an arc shape at the end of the curved portion 27b, for example.

[0084] In the above example, an example was described in which the ischial support portion 26 has a pair of slits 27 extending parallel to each other. However, the pair of slits 27 do not have to extend parallel to each other. Also, the ischial support portion 26 may have only one slit 27. Thus, the orientation and number of slits 27 are not particularly limited.

[0085] In the cushion 21 configured as described above, when a user sits on the seating portion 22, each of the pair of ischial support portions 26 has a recess that is recessed from the upper surface 24b of the buttock support portion 24. Furthermore, the curvature of the recess is greater than the curvature of the upper surface 24b of the buttock support portion 24. Therefore, the user's ischial bones E6 can be securely positioned in the recess of the ischial support portion 26 with greater curvature, thereby more reliably suppressing displacement of the ischial bones E6 when sitting, and achieving the same effects as the cushion 1 described above.

[0086] Next, the cushion 41 relating to the second modified example will be described with reference to Figure 12(a). As shown in Figure 12(a), cushion 41 differs from cushion 1 in that it does not have a lumbar support portion 12 and an iliac support portion 13. The lumbar support portion 43 of cushion 41 has a convex portion 44 that becomes higher towards the center in the second direction D2, and a convex sacral support portion 11 that protrudes forward from the front surface 44b of the convex portion 44.

[0087] Furthermore, the cushion 51 relating to the third modified example will be described with reference to Figure 12(b). As shown in Figure 12(b), the cushion 51 differs from the cushion 1 in that it does not have a lumbar support portion 3. The cushion 51 has the aforementioned seating portion 2 and a projection portion 52 that protrudes from the rear end of the seating portion 2. The upper surface of the projection portion 52 is, for example, a curved surface.

[0088] Furthermore, the cushion 61 relating to the fourth modified example will be described. Figure 13 is a perspective view showing the cushion 61. Figure 14 is a plan view showing the cushion 61. Figure 15 is a cross-sectional view of Figure 14 along line CC. Figure 16 is a front view showing the cushion 61. Figure 17 is a cross-sectional view of Figure 14 along line DD. Figure 18 is a bottom view showing the cushion 61.

[0089] As shown in Figure 13, the cushion 61 includes a seating portion 62. The seating portion 62 has a buttock support portion 64 and a thigh support portion 65. The seating portion 62 has a pair of thigh support portions 65 aligned along a second direction D2. The pair of thigh support portions 65 are, for example, positioned spaced apart from each other. Each of the user's thighs is placed on each of the pair of thigh support portions 65. The buttock support portion 64 has a pair of ischial support portions 66. Unlike the ischial support portions 6 of the cushion 1 described above, each ischial support portion 66 does not have a recess 6b. Each ischial support portion 66 has a through hole 66b. The through hole 66b penetrates downward from the upper surface 64b of the buttock support portion 64. 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 easily concave than the parts of the buttock support portion 64 other than the ischial support portion 66.

[0090] As shown in Figure 14, the shape of the through-hole 66b in plan view may be similar to the shape of the ischial support portion 6 of the cushion 1 in plan view as described above. For example, the shape of the through-hole 66b in plan view may be oval (or elliptical). 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.

[0091] Ventilation holes 62a are formed in the seating portion 62. The ventilation holes 62a penetrate downward from the upper surface 64b of the buttock support portion 64 or the upper surface of the thigh support portion 65. The upper end of the inner wall defining the ventilation hole 62a may be rounded with an R-chamfer. In a plan view, multiple ventilation holes 62a may be arranged in a line from rear to front. For example, in a plan view (a plan view when the lumbar support portion 73 is positioned above the seating portion 62), multiple ventilation holes 62a (six as an example) may be arranged on each side (left and right sides) of the second direction D2.

[0092] As an example, three ventilation holes 62a are arranged on each side of the second direction D2. For example, two ventilation holes 62a are arranged side by side along the second direction D2, and the distance between the two ventilation holes 62a arranged side by side along the second direction D2 increases as you move from the buttock support portion 64 toward the thigh support portion 65. As an example, multiple ventilation holes 62a are arranged to form a V-shape in a plan view. For example, in the cushion 61, the through holes 66b are formed by urethane molding, and the ventilation holes 62a are formed by punching. In this case, the part of the mold used to manufacture the cushion 61 that forms the ventilation holes 62a can be made unnecessary, thus simplifying the shape of the mold. Furthermore, when molding liquid urethane with the mold, an escape route for air in the liquid urethane can be secured, resulting in a cleaner finish for the cushion 61.

[0093] Figure 15 is a cross-sectional view of the cushion 61, obtained by cutting the cushion 61 along a plane extending in the first direction D1 and the third direction D3. For example, when a user sits on the seating portion 62, the thickness of the thigh support portion 65 is thinner than the thickness of the seating portion 62 other than the thigh support portion 65. In this case, the thigh support portion 65 deforms under load so that it becomes thinner than the rest of the seating portion 62. For example, when a user sits on the seating portion 62, the amount of deformation of the thigh support portion 65 is greater than the amount of deformation of the rest of the seating portion 62. In this case, the thigh support portion 65 is more easily deformed under load than the rest of the seating portion 62.

[0094] For example, when a user sits on the seat 62, the thigh support portion 65 deforms more than the inclined surface 7 when the user sits on the seat 62. When a user sits on the seat 62, the thigh support portion 65 may deform such that the inclination angle θ2 decreases as it moves from the inclined surface 7 towards the front end of the thigh support portion 65. Also, when no load is applied, the thickness of the thigh support portion 65 may be thinner than the thickness of the parts of the seat 62 other than the thigh support portion 65. In this case as well, the user's thighs can be prevented from rising too high.

[0095] Each thigh support portion 65 has a recess 65d 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 located spaced apart from each other. The depth of the recesses 65d increases as it moves away from the buttock support portion 64 (towards the front). For example, the thigh support portion 65 has a recess 65d that defines a space B between itself and the mounting surface S on which the cushion 61 is placed.

[0096] The recess 65d is formed, for example, on the lower surface 61b of the cushion 61. 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 in which the recess 65d is formed may be thinner than the thickness of the portion of the seating portion 62 other than the thigh support portion 65. As an example, the space B defined between the recess 65d and the mounting surface S is formed to expand as it extends from the rear to the front. The cross section of space B perpendicular to the first direction D1 may widen as it extends from the rear to the front. As an example, the outer edge of the recess 65d may be located on both the lower surface 61b and the inclined portion 65f.

[0097] As shown in Figure 13, the cushion 61 has a general section 70 and a lumbar support section 73. The lumbar support section 73 has a convex section 74 that becomes higher towards the center in the second direction D2, and a convex sacral support section 71 that protrudes forward from the front surface 70h of the general section 70. For example, the convex section 74 and the convex section 9 are continuous. As shown in Figure 16, when viewed along the first direction D1, the entire lumbar support section 73 may have an inverted U shape.

[0098] As shown in Figures 16 and 17, the sacral support portion 71 has a protruding surface 71a. The protruding surface 71a has a curved shape that protrudes forward. For example, when viewed along the second direction D2, the protruding surface 71a may have a curved shape that protrudes 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 inside of the protruding surface 71a.

[0099] The projected area of ​​the lower surface 61b of the cushion 61 is smaller than the projected area of ​​the cushion 61 when viewed from above. For example, as shown in Figure 15, when viewed along the second direction D2, the inclined portion 65f of the thigh support portion 65 extends rearward and diagonally downward from the top portion 65e of the thigh support portion 65. That is, the inclined portion 65f is inclined toward the center of the cushion 61 in the first direction D1 as it approaches the lower surface 61b. The top portion 65e is located, for example, at the front end of the cushion 61.

[0100] When viewed along the second direction D2, the outer surface 70f constituting the first portion 70b of the general part 70 is inclined toward the center of the cushion 61 in the first direction D1 as it approaches the bottom surface 61b. As shown in Figure 16, when viewed along the first direction D1, the cushion 61 has an inclined portion 9c that is inclined toward the center of the cushion 61 in the second direction D2 as it approaches the bottom surface 61b from the top portion 9b. The cushion 61 has, for example, a pair of inclined portions 9c aligned along the second direction D2. The top portion 9b may be located 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 as it moves away from the bottom surface 61b.

[0101] Furthermore, the thigh support portion 65 does not necessarily have to have a recess 65d. At least a portion of the thigh support portion 65 may be made of a material that is more easily deformed by load than the material of the other parts of the seating portion 62.

[0102] Next, the effects and benefits obtained from the cushion 61 according to the fourth modified example will be explained. As shown in Figure 13, the buttock support portion 64 has a pair of ischial support portions 66 arranged along the second direction D2 (left-right direction). Each ischial support portion 66 has a through hole 66b that penetrates downward from the upper surface 64b of the buttock support portion 64. Therefore, when the user sits on the seating portion 62, the ischial bones E6 (see Figure 6) of the user's buttocks fit into each through hole 66b, thereby suppressing displacement of the ischial bones E6 and reducing the force applied to the ischial bones E6.

[0103] As shown in Figure 17, in the fourth modified example, the sacral support portion 71 has a protruding surface 71a. The protruding surface 71a is a curved surface that protrudes forward. Therefore, compared to the case where the protruding surface of the sacral support portion is flat, the user can feel a force pushing the sacrum E5 (see Figure 6) forward.

[0104] As mentioned above, the thickness of the thigh support portion 65 when the user sits on the seat portion 62 may be thinner than the thickness of the parts of the seat portion 62 other than the thigh support portion 65 when the user sits on the seat portion 62. In this case, when the user sits on the seat portion 62, the thigh support portion 65 becomes thinner compared to the parts of the seat portion 62 other than the thigh support portion 65, so that the position of the user's thighs does not rise too high. Therefore, the pressure on the seated user is more easily distributed from the buttocks to the thighs, so the pressure on the seated user's buttocks can be reduced.

[0105] As mentioned above, the amount of deformation of the thigh support portion 65 when a user sits on the seat portion 62 may be greater than the amount of deformation of the parts of the seat portion 62 other than the thigh support portion 65 when a user sits on the seat portion 62. In this case, when a user sits on the seat portion 62, the amount of downward deformation of the thigh support portion 65 is greater than that of the parts of the seat portion 62 other than the thigh support portion 65, so that the position of the user's thighs does not rise too high. Therefore, the pressure on the seated user is more easily distributed from the buttocks to the thighs, so the pressure on the seated user's buttocks can be reduced.

[0106] As shown in Figure 15, the thigh support portion 65 has a recess 65d that is recessed in the thickness direction of the cushion 61. Therefore, the thigh support portion 65 can be deformed more easily than the other parts of the seating portion 62. Thus, when the thighs are placed on the thigh support portion 65, it is possible to move the thigh support portion 65 further downward, making it more difficult for the thighs to rise and reducing discomfort for the user. The depth of the recess 65d of the thigh support portion 65 increases as it moves away from the buttock support portion 64. That is, the depth of the recess 65d of the thigh support portion 65 increases as it moves forward from the perspective of the user seated on the seating portion 62. Therefore, the front part of the thigh support portion 65 can be deformed more easily downward compared to the buttock support portion 64, so the rising of the thighs can be suppressed more reliably. Thus, discomfort for the user can be reduced and the sitting comfort on the cushion 61 can be improved.

[0107] The thigh support portion 65 has a recess 65d that defines a space B between itself and the mounting surface S on which the cushion 61 is placed. When the user's thighs are placed on the thigh support portion 65, the thigh support portion 65 easily deforms so as to reduce the space B. Therefore, the thigh support portion 65 can be deformed more easily downwards, which suppresses the thighs from rising and further improves the sitting comfort. In addition, as the thigh support portion 65 sinks in so as to reduce the space B, the user can feel as if their thighs are being cradled by the thigh support portion 65.

[0108] As described above, in the fourth modified example, the recess 65d is formed such that the space B defined between the recess 65d and the mounting surface S expands as it extends from the rear to the front. When the user sits on the seating portion 62, the thigh support portion 65 can be deformed more easily as the space B expands as it extends from the rear to the front. For example, a 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 in using the outer edge of the recess 65d located on the lower surface 61b as a fulcrum.

[0109] As mentioned 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 when viewed from above. In this case, the area of ​​the seat portion 62 when viewed from above 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. Therefore, the cushion 61 can be placed on a mounting surface S with an area smaller than the area of ​​the seat portion 62 when viewed from above. Consequently, the cushion 61 can be placed on the seat surfaces of various chairs, improving the versatility of the cushion 61.

[0110] As described above, in the fourth modified example, the top portion 65e is located at the front end of the cushion 61. The inclined portion 65f is inclined toward the center of the second direction D2 of the cushion 61 as it moves from the top portion 65e toward the bottom 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, which has been deformed to bend downward as a whole.

[0111] As shown in Figure 14, in the fourth modified example, ventilation holes 62a are formed in the seating portion 62. The ventilation holes 62a penetrate downward from the upper surface 64b of the buttock support portion 64 or the upper surface of the thigh support portion 65. Therefore, stuffiness between the user's buttocks and thighs and the seating portion 62 is suppressed.

[0112] As shown in Figure 16, when viewed along the first direction D1, the entire lumbar support portion 73 may have an inverted U-shape. In this case, the lumbar support portion 73 can be made less prone to bending than the lumbar support portion 43 shown in Figure 12(a), where the convex portion 44 protrudes locally. Also, since the shape is simpler than the cushion 1 shown in Figure 1, the cushion 61 can be easily manufactured.

[0113] Furthermore, a fifth modified example of cushion 81 will be described. Figure 19 is a perspective view showing cushion 81. Figure 20 is a plan view showing cushion 81. Figure 21 is a bottom view showing cushion 81. Figure 22 is a front view showing cushion 81. Figure 23 is a cross-sectional view of line EE in Figure 20. As shown in Figures 19 to 23, cushion 81 differs from cushion 61 in that it has an ischial support portion 86 that is different from the ischial support portion 66, and a sacral support portion 91 that is different from the sacral support portion 71.

[0114] In cushion 81, the buttock support portion 64 has a pair of ischial support portions 86. Each ischial support portion 86 has a through hole 86b that penetrates downward from the upper surface 64b of the buttock support portion 64. Each ischial support portion 86 has a tapered surface 86h located between the inner wall 86c that defines the through hole 86b and the upper surface 64b of the buttock support portion 64. The ischial support portion 86 differs from the ischial support portion 66 of cushion 61 in that it has a tapered surface 86h.

[0115] As shown in Figures 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, for example, similar to that of the through-hole 66b. For example, the shape of the through-hole 86b in plan view is oval (or elliptical). The inner wall 86c that defines 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 rounded with an R-chamfer. The end of the inner wall 86c on the tapered surface 86h side may also be rounded with an R-chamfer.

[0116] The tapered surface 86h connects the inner wall 86c and the upper surface 64b. The tapered surface 86h forms a recess that is recessed to the upper surface 64b. The tapered surface 86h is inclined such that its opening end widens in diameter towards the upper surface 64b. In a 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 of the tapered surface 86h that is rounded by an R-chamfer.

[0117] The shape of the tapered surface 86h in plan view may be similar to the shape of the ischial support portion 6 of the cushion 1 in plan view as described above. For example, the shape of the tapered surface 86h in plan view is oval (or elliptical). The position of the tapered surface 86h is, for example, the same as the position of the recess 6b of the cushion 1 described above.

[0118] In cushion 81, the lumbar support portion 73 has a convex sacral support portion 91 that protrudes forward from the front surface 70h of the general portion 70. The sacral support portion 91 has a curved protruding surface 91a that protrudes forward and a recessed portion 91b that is recessed backward from the protruding surface 91a. The sacral support portion 91 differs from the sacral support portion 71 of cushion 61 in that it has a recessed portion 91b.

[0119] As shown in Figure 22, the recessed portion 91b extends in a third direction D3 and a 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 as viewed from the first direction D1 may be a groove shape (or oval shape) extending in the third direction D3. The recessed portion 91b includes a bottom surface 91c and an inner surface 91d that connects the bottom surface 91c and the protruding surface 91a. When viewed from the first direction D1, the inner surface 91d has an annular shape surrounding the bottom surface 91c. The inner surface 91d may include a rounded surface that connects the bottom surface 91c and the protruding surface 91a.

[0120] As shown in Figure 20, in a plan view, the bottom surface 91c is curved so as it moves away from the end of the recessed portion 91b in the second direction D2, it curves backward. The curvature of the bottom surface 91c in a plan view may be the same as the curvature of the protruding surface 91a in a plan view.

[0121] As shown in Figure 23, in a cross section (side cross section) perpendicular to the second direction D2, the bottom surface 91c is curved so as it moves away from the end of the recessed portion 91b in the third direction D3, it curves backward. The curvature of the bottom surface 91c in the side cross section may be the same as the curvature of the protruding surface 91a in the side cross section.

[0122] The recessed portion 91b is the area into which the user's sacrum E5 (see Figure 6) fits. 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 recessed portion 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 recessed portion 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 values ​​and may be 1.5 cm or more. Also, the recessed portion 91b may penetrate the sacral support portion 91 in the first direction D1. Furthermore, the recessed portion 91b may penetrate the lumbar support portion 73 in the first direction D1.

[0123] Next, the effects and benefits obtained from the cushion 81 according to the fifth modified example will be explained. As shown in Figure 19, each ischial support portion 86 has an inner wall 86c of the through hole 86b that defines the through hole 86b and a tapered surface 86h located between the inner wall 86c of the through hole 86b and the upper surface 64b of the buttock support portion 64. Therefore, because the tapered surface 86h exists between the inner wall 86c of the through hole 86b and the upper surface 64b of the buttock support portion 64, the inner wall 86c of the through hole 86b smoothly connects to the upper surface 64b of the buttock support portion 64 via the tapered surface 86h. Thus, when the user sits on the seating portion 62, the ischial bones E6 that enter the through hole 86b can be gently supported by the tapered surface 86h, further reducing the force on the ischial bones E6.

[0124] The sacral support portion 91 has a protruding surface 91a that projects forward and a recessed portion 91b that recesses backward from the protruding surface 91a. Therefore, the user's sacrum E5 can be supported by the protruding surface 91a while the sacrum E5 can be inserted into the recessed portion 91b. Thus, the sacrum E5 can be supported from both sides of the recessed portion 91b and the pressure on the sacrum E5 can be reduced, thereby preventing excessive pressure on the sacrum E5 and providing gentle support for the sacrum E5.

[0125] The recessed portion 91b may extend in the third direction D3 and the second direction D2. As shown in Figure 20, in plan view, the bottom surface 91c may curve so as to recess posteriorly as it moves away from the end of the recessed portion 91b in the second direction D2. In this case, the posterior curvature of the bottom surface 91c in plan view can further alleviate pressure on the sacrum E5.

[0126] As shown in Figure 23, in a cross-section perpendicular to the second direction D2, the bottom surface 91c may be curved so as it moves away from the end of the recessed portion 91b in the third direction D3. In this case, the backward curvature of the recessed portion 91b in a side view can further alleviate the pressure on the sacrum E5.

[0127] The embodiments of the cushion according to this disclosure and the first to fifth modifications have been described above. However, this disclosure is not limited to the embodiments or the first to fifth modifications described above, 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 embodiments or various modifications described above, and can be further modified within the scope of the gist described above. For example, the cushion according to this disclosure may be a combination of two or more of the embodiments, the first to fifth modifications described above, and the various modifications described later.

[0128] For example, the embodiments and modifications described above describe a cushion comprising a seating portion and a lumbar support portion. However, the height of the lumbar support portion can be changed as appropriate. For example, the height of the upper end of the lumbar support portion may be the height of the user's back, the height of the user's shoulders, or the height of the user's head, and is not particularly limited. In this case, the cushion can be used as a chair such as a gaming chair.

[0129] For example, the cushion may have a foldable lumbar support section relative to the seating section. In this case, the cushion can be used as an office chair, recliner, or full-flat seat. The cushion may also be a seat used in transportation machinery such as automobiles, railway vehicles, or aircraft.

[0130] Furthermore, for example, a rigid support member may be provided below the seating area. In this case, the seating area is less prone to deformation and can more firmly support the user's buttocks and thighs. A rigid support member may also be provided at the rear of the lumbar support area. In this case, the lumbar support area is less prone to deformation and can more firmly support the user's waist. The support member may be made of, for example, a chip board or a rigid resin. The seating area and the lumbar support area may be connected to each other by the support member. In this case as well, the cushion can be used as a cushion for a chair such as an office chair.

[0131] The lumbar support and sacral support do not have to be a single unit. For example, the sacral support may be detachably joined to the lumbar support. For example, the sacral support may be detachably joined to the lumbar support by a joining member. In this case, the sacral support, which is joined to the lumbar support of one cushion via a joining member, can be removed and attached to the lumbar support of another cushion different from the first cushion. In this way, the sacral support can be attached to and detached from the lumbar support of various cushions. The joining member may be, for example, a hook-and-loop fastener, a snap fastener, or a button, and the type of joining member is not particularly limited.

[0132] In the first modified example described above, a cushion 21 made of two-dimensionally cut foamed urethane was described as an example of a flexible material. For example, this cushion 21 may have a soft layer and a hard layer. For example, the protrusions 21b and 23b may be made of a soft layer, and the layer below the protrusion 21b and the layer behind the lumbar support portion 23 may be made of a hard layer. In this case, the user's buttocks, thighs, back, and waist can be held more firmly.

[0133] The inclination angle θ2 of the inclined surface 7 shown in Figures 3 and 15 may be 0° or greater and less than 5°. In the cushion according to this 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 this disclosure does not have to have an inclined surface that extends diagonally upward from the buttock support portion toward the thigh support portion.

[0134] As shown in Figures 18 and 21, the modified examples described above illustrate cushions 61 and 81 having a pair of thigh support parts 65, each thigh support part 65 having a recess 65d, and the pair of recesses 65d being provided at positions spaced apart from each other. However, the shape and configuration of the thigh support parts are not limited to the above examples. For example, the cushion may have one recess that includes the pair of thigh support parts 65. That is, the pair of thigh support parts 65 may share one recess. In this case, the pair of recesses 65d described above are connected to each other and formed as a single recess.

[0135] In the modified example described above, a cushion comprising an ischial support portion, an inclined portion, and a sacral support portion was illustrated. However, the cushion may not have an ischial support portion and may, for example, only have a sacral support portion 91. In this case, the sacral support portion 91 has a protruding surface 91a that projects forward and a recessed portion 91b that recesses backward from the protruding surface 91a. Therefore, the user's sacrum E5 can be supported by the protruding surface 91a while the sacrum E5 can be placed in the recessed portion 91b, thus achieving the same effect as the cushion 81 described above.

[0136] Furthermore, the cushion may not have at least one of the inclined portion and the sacral support portion, and may, for example, be a cushion having only a pair of thigh support portions 65. In this case, each of the pair of thigh support portions 65 has a recess 65d that is recessed in the thickness direction of the cushion. Therefore, each thigh support portion 65 can be made more easily deformable than the other parts of the seating portion, so that the same effect as the cushion 61 described above can be obtained.

[0137] (Examples) Next, a comparative example without a cushion and examples of cushions according to Examples 1, 2, 3, and 4 will be described. Note that the present invention is not limited to the examples described later. In the experiments according to the examples, the pressure distribution of body pressure applied to the user seated on each cushion or chair was measured, and the maximum and average pressures were calculated. The pressure distribution was measured using a pressure distribution measuring device from Xsensor.

[0138] The cushion according to Example 1 includes a portion corresponding to the sacral support portion 71 of cushion 61, as illustrated in Figure 13. The cushion according to Example 2 includes a portion corresponding to the sacral support portion 91 of cushion 81, as illustrated in Figure 19. That is, the cushion according to Example 2 differs from the cushion according to Example 1 in that it has a recessed portion 91b. The cushion according to Example 3 includes a portion corresponding to the thigh support portion 5 of cushion 1, as illustrated in Figure 1. The cushion according to Example 4 includes a portion corresponding to the thigh support portion 65 of cushion 61, as illustrated in Figure 13. That is, the cushion according to Example 4 differs from the cushion according to Example 3 in that it has a recessed portion 65d.

[0139] Figure 24 shows experimental results (measured data) illustrating the pressure distribution in a comparative example where a user sat on a chair without a cushion. In Figure 24, and the measured data in Figures 25(a), 25(b), 26(a), and 26(b) described later, the pressure distribution of the seated user is shown inside a black background for ease of understanding. In this pressure distribution, areas where the user experienced high pressure are shown in a color close to black, and areas where the user experienced low pressure are shown in a color close to white. In Figure 24, the left side shows the area corresponding to the ischial tuberosities, and the right side shows the area corresponding to the thighs. As shown in Figure 24, the comparative example showed a generally high pressure distribution, and it was found that pressure was particularly concentrated on the user's ischial tuberosities. In the comparative example in Figure 24, the user experienced a maximum pressure of 167.6 mmHg and an average pressure of 45.8 mmHg.

[0140] Figure 25(a) shows the experimental results (measured data) of the pressure distribution in Example 1. In Example 1, the pressure distribution was measured when a user sat on the cushion according to Example 1. Figure 25(b) shows the experimental results (measured data) of the pressure distribution in Example 2. In Example 2, the pressure distribution was measured when a user sat on the cushion according to Example 2. Figures 25(a) and 25(b) show the region X1 corresponding to the sacrum, the region corresponding to the thigh, and the region corresponding to the ischium located between region X1 and the region corresponding to the thigh.

[0141] As shown in Figures 25(a) and 25(b), in Examples 1 and 2, the area of ​​high pressure was reduced compared to the comparative example in Figure 24, indicating that the pressure applied to the user's ischial tuberosities was distributed. 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 in Examples 1 and 2 can distribute the pressure applied to the user's ischial tuberosities.

[0142] In Example 2, compared to Example 1, the area of ​​high pressure was further reduced, indicating that the pressure applied to the user's sacrum E5 was more evenly distributed. In the area X1 corresponding to the sacrum E5 in Example 1, the user experienced a maximum pressure of 95.5 mmHg and an average pressure of 42.2 mmHg. In the area X1 corresponding to the sacrum E5 in Example 2, the user experienced a maximum pressure of 100.3 mmHg and an average pressure of 35.6 mmHg.

[0143] In Example 1, an average pressure of 55.0 mmHg was applied to the user in the central region X2 of region X1 corresponding to the sacrum E5. In Example 2, an average pressure of 33.1 mmHg was applied to the user in the central region X2 of region X1 corresponding to the sacrum E5. From the above, it was confirmed that the cushion of Example 2, in which the sacral support portion has a part corresponding to the recessed portion 91b, can better distribute the pressure applied to the sacrum E5.

[0144] Figure 26(a) shows the experimental results (measured data) of the pressure distribution in Example 3. In Example 3, the pressure distribution was measured when the user sat on the cushion according to Example 3 in a forward-leaning posture. Figure 26(b) shows the experimental results (measured data) of the pressure distribution in Example 4. In Example 4, the pressure distribution was measured when the user sat on the cushion according to Example 4 in a forward-leaning posture. Figures 26(a) and 26(b) show the pressure distribution in the area corresponding to the thighs.

[0145] As shown in Figures 26(a) and 26(b), in Example 4, the area of ​​high pressure was further reduced compared to Example 3, indicating that the pressure applied to the user's thigh was further distributed. 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 support portion has a portion corresponding to the recess 65d, can more significantly distribute the pressure applied to the thigh. [Explanation of Symbols]

[0146] 1...Cushion, 1b...Bottom surface, 2...Seating area, 3...Lumber support area, 3b...Front end, 3c...Slanted surface, 4...Buttock support area, 4b...Top surface, 4c...Bottom part, 5...Thigh support area, 5b...Top part, 5c...Curved part, 6...Ichial bone support area, 6b...Concave part, 6c...Corner part, 6d...Long axis, 6f...Short axis, 6g...Center , 6h...Curved surface, 7...Slanted surface, 8...Convex part, 8b...Top part, 8c...Slanted part, 9...Protrusion part, 9b...Top part, 9c...Slanted part, 10...General part, 10b...First part, 10c...Second part, 10d...Inner surface, 10f...Outer surface, 10g...Concave part, 10h...Front surface, 11...Sacral support part, 11b...Long axis, 11 c...short axis, 11d...upper end, 11g...protruding surface, 11h...center, 12...lumbar support part, 13...iliac support part, 21...cushion, 21b...convex part, 21c...slit, 21d...bottom surface, 21f...straight part, 21g...expanded part, 22...seating part, 22b...upper slit, 22c...straight part, 22d...expanded part, 23...lumbar support part, 23b...convex part, 23c...slit, 23d...posterior surface, 23f...straight part, 23g...expanded part, 23h...front slit, 23j...narrow part, 23k...expanded part, 24...buttock support part, 24b...upper surface, 25...thigh support part, 26...ischial support part, 27...s Lit, 27b...Curved section, 27c...Expanded section, 28...Deformed section, 29...Inclined surface, 31...Sacral support section, 32...Lumbar support section, 41...Cushion, 43...Lumbar support section, 44...Convex section, 44b...Front surface, 51...Cushion, 52...Protruding section, 61...Cushion, 61b...Bottom surface, 62...Seating section, 62a...Ventilation hole, 64...Buttock support section, 64b...Top surface, 65...Thigh support section, 65d...Concave section, 65e...Top, 65f...Inclined section, 66...Ischial support section, 66b...Through hole, 70...General section, 70b...First section, 70f...Outer surface, 70h...Front surface, 71...Sacral support section, 71a...Protruding surface 73...Lumbar support part, 74...Convex part, 86...Ischial support part, 86b...Through hole, 86c...Inner wall, 86e...Curved surface, 86h...Tapered surface, 91...Sacral support part, 91a...Protruding surface, 91b...Recessed part, 91c...Bottom surface, 91d...Inner surface, B...Space, D1...First direction, D2...Second direction, D3...Third direction, D4...Long axis direction, D5...Short axis direction, E1...Spine, E2...Pelvis, E3...Ilium, E4...Pubis, E5...Sacrum, E6...Ischial, G1, G2...Convex part group, L1, L2...Extension line, L3...Imaginary line, P...Intersection, S...Placement surface, X1, X2...Region, θ1...Intersection angle, θ2...Inclination angle.

Claims

1. A cushion made of flexible material, The seating area comprises a buttock support section on which the user's buttocks rest, and a pair of thigh support sections on which each of the user's thighs rests. Each of the thigh support portions has a recess that is recessed in the thickness direction of the cushion, The depth of the recess increases as it moves away from the buttock support portion. The seating portion has an inclined surface that extends diagonally upward from the buttock support portion toward the thigh support portion. The aforementioned thigh support portion is, The top portion located at the front end of the inclined surface and the front end of the cushion, An inclined portion extending rearward and diagonally downward from the top towards the lower surface of the cushion, including, cushion.

2. The thickness of the thigh support portion when the user is seated on the seat is thinner than the thickness of the portion of the seat other than the thigh support portion when the user is seated on the seat. The cushion according to claim 1.

3. The amount of deformation of the thigh support portion when the user sits on the seat portion is greater than the amount of deformation of the portion of the seat portion other than the thigh support portion when the user sits on the seat portion. The cushion according to claim 1 or 2.

4. The recess is formed on the lower surface of the cushion, The cushion according to any one of claims 1 to 3.

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