JP5038784B2 - Seat cushion structure - Google Patents

Description

  The present invention relates to a seat cushion structure particularly suitable for use in a vehicle seat such as an automobile.

A seat of a vehicle such as an automobile is required to be able to maintain a stable sitting posture so that the body does not shake due to a comfortable sitting comfort, cornering, vibrations received from a road surface, and the like.
In other words, the seat needs to be flexible in order to ensure a comfortable seating comfort, but also has a relatively high elasticity to maintain a stable seating posture and to support the weight of the seated person. Need to be.

Therefore, for example, as shown in FIG. 17, a seat formed by a cushion structure in which a cushion body 100 made of urethane or the like is covered with a skin material 110 is known. The cushion body 100 includes a first cushion body 101 having a relatively high elastic force as a base, and a second cushion body 102 laminated on the first cushion body 101 and having a relatively low elastic force. Such a technique is disclosed in Patent Document 1, for example.
Japanese Patent No. 3048138

However, when traveling for a long time due to long-distance driving or traffic jams, the occupant's buttocks continue to be pressed against the seat, and the more elastic the seat, the more likely fatigue accumulates. is there.
The present invention has been devised in view of such a problem, and an object of the present invention is to provide a seat cushion structure that distributes the seating pressure of a person seated on the seat and can reduce fatigue. To do.

In order to achieve the above object, the seat cushion structure of the present invention according to claim 1 is a cushion structure for a seat on which a person is seated, the first cushion body serving as a base, and the cushion structure for the first cushion body. A second cushion body that is disposed on the upper surface and has less elasticity than the first cushion body, and the upper surface of the first cushion body faces downward in the portion where the sciatic bone of the person sitting is located. A lower portion of the second cushion body is formed so as to follow the shape of the hollow portion, and has a convex portion that is in close contact with the hollow portion , The first cushion body is divided into a front edge portion and a main body portion in the front-rear direction, and has a high elasticity, a middle elasticity, and a low elasticity in the order of the main body portion, the front edge portion, and the second cushion body. It characterized by elasticity is formed There.

A seat cushion structure according to a second aspect of the present invention is the seat cushion structure according to the first aspect, wherein the seat cushion structure is fitted into the recess and is formed between an upper surface of the first cushion body and a lower surface of the second cushion body. It is characterized by comprising a cushion piece which is sandwiched and has less elasticity than the second cushion body.

The cushion structure for a seat according to claim 3 of the present invention is the cushion structure for a seat according to claim 1 or 2, further comprising an outer skin that tightly covers the upper surface of the second cushion body, It is characterized by being composed of a fabric having an elongation rate of 30% or more.
A seat cushion structure according to a fourth aspect of the present invention is the seat cushion structure according to the third aspect , wherein the skin is a jersey simulating a suede fabric.

According to the cushion structure for a seat of the present invention as set forth in claim 1, the seat is formed by the two-layer cushion structure of the first cushion body and the second cushion body, and the sciatic bone mainly supporting the weight at the time of sitting is located. In the portion to be formed, the depression is formed on the upper surface of the relatively hard first cushion body, so that the thickness of the first cushion body in the portion where the sciatica is located can be reduced.
Therefore, the elasticity of the seat where the ischia is located becomes relatively small, the seating pressure of the seated person can be dispersed, and fatigue can be reduced well.
Moreover, according to the cushion structure for seats of this invention of Claim 1, a comparatively soft 2nd cushion body is advanced to a hollow part with a convex part, and the thickness of the 2nd cushion body of the part in which a sciatic bone is located is set. Can be thicker.
Therefore, the elasticity of the seat where the ischia is located becomes relatively small, the seating pressure of the seated person can be dispersed, and fatigue can be reduced well.
Furthermore, according to the cushion structure for a seat of the present invention described in claim 1, since the elasticity of the front edge of the seat is relatively small, while sufficiently supporting the weight of the seated person by the main body portion of the first cushion body, The thigh can be reduced from being pressed by the seat.
In particular, when the seat cushion structure of the present invention is applied to the driver's seat of a vehicle such as an automobile, vibration applied to the vehicle is transmitted from the foot to the whole body, but the soft front edge absorbs the vibration, By suppressing the transmission of vibration to the driver, the driver's fatigue can be reduced. Further, since the thigh is not easily pressed by the seat, it is effective in reducing fatigue associated with the depression operation of the accelerator pedal or the brake pedal.

According to the cushion structure for a seat of the present invention as set forth in claim 2 , the cushion piece relatively reduces the elasticity of the seat where the ischia is located, disperses the seating pressure of the seated person, and reduces fatigue well. can do.
In addition, the dispersion of the sitting pressure can be easily adjusted by changing the elasticity of the cushion piece.

According to the cushion structure for a seat of the present invention as set forth in claim 3 , the epidermis is made of a fabric having an elongation rate of 30% or more, so that it can follow the sinking of the second cushion body well when a person is seated. Elongation and the elasticity of the first cushion body and the second cushion body can be favorably reflected in the seat pressure.
According to the cushion structure for a seat of the present invention according to claim 4 , since the skin is a jersey that simulates a suede fabric, in addition to the elongation that extends following the sinking of the second cushion body when a person is seated, It is possible to ensure a sliding angle that prevents the seated person from sliding forward. And the epidermis extends following the sinking of the second cushion body, and the elasticity of the first cushion body and the second cushion body can be reflected well in the seating pressure, and at the same time preventing the seated person from slipping forward Thus, the user can be seated stably and the fatigue can be further reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
1 to 8 are views showing a cushion structure for a seat according to a first embodiment of the present invention, in which FIG. 1 is a cross-sectional view in the width direction (A-A cross-sectional view in FIG. 3), and FIG. 3 is a perspective view, FIG. 4 is a graph showing the elongation and slip angle (grip rate) of the skin, and FIGS. 5 to 8 are molding methods thereof. It is a figure explaining each process of.

  Moreover, FIGS. 9-13 is a figure which shows the experimental result which concerns on the seat formed with the cushion structure for seats, Comprising: Fig.9 (a) is right after seating of the person seated on the seat which concerns on this embodiment. FIG. 9B is a graph showing the sitting pressure distribution immediately after the person sitting on the conventional seat, and FIG. 10A is a long time of the person sitting on the seat according to the present embodiment. FIG. 10B is a graph showing the seat pressure distribution after sitting for a long time of a person seated on a conventional seat, and FIG. 11 is an evaluation of the fatigue level of the person seated on the seat. FIG. 12 is a graph showing the relationship between the seating pressure and the degree of fatigue when seated on the seat, and FIG. 13 is a graph showing the vibration characteristics of the seat.

<Configuration>
Here, a case where the seat cushion structure of the present invention is applied to a seat of a vehicle such as an automobile will be described.
The seat cushion structure of the first embodiment is applied to a seat surface portion (hereinafter simply referred to as a seat) of a seat 1 on which an occupant sits, as shown in FIG. Here, the seat 1 has a raised portion 2 formed at each of both ends in the width direction, and a flat portion 3 formed between the raised portions 2 and having a substantially flat surface shape. And this bulge part 2 wraps up a seated person's buttocks, and suppresses the swing (movement) to the width direction. However, the shape of the seat 1 is not limited to this, and may be, for example, a simple flat shape without the raised portion 2.

As shown in FIGS. 1 and 2, the seat cushion structure is disposed on the upper surface of the first cushion body 10 serving as a base and the first cushion body 10, and is more elastic than the first cushion body 10. A small second cushion body 20 and a skin 30 that covers the upper surface of the second cushion body 20 and the side surface of the first cushion body 10 in close contact with each other are provided.
Among these, the 1st cushion body 10 is comprised with the foam which consists of a polyurethane foam (foaming resin). And the 1st cushion body 10 is formed so that the external shape of the seat 1 may be prescribed | regulated, and in order to form the protruding part 2 of the seat 1, as shown in FIG. ) 10s is raised.

Moreover, as shown in the broken line of FIG. 3 and FIG. 1, the upper surface of the 1st cushion body 10 has the hollow part 11 which curves and dents gently toward the downward direction in the part in which a seated person's sciaticus is located. ing. The recess 11 is formed in a substantially elliptical shape extending in the front-rear direction when viewed from above.
Further, as shown in FIG. 2, the first cushion body 10 is divided into a front edge portion 10f and a main body portion 10m in the front-rear direction, and the front edge portion 10f is more elastic than the main body portion 10m. It is formed small. Here, the elasticity of the main body portion 10m, the front edge portion 10f, and the second cushion body 20 of the first cushion body 10 is formed larger in this order. Hereinafter, the elasticity of the main body portion 10m, the front edge portion 10f, and the second cushion body 20 is referred to as high elasticity (high hardness), medium elasticity (medium hardness), and low elasticity (low rebound, low hardness), respectively. In addition, the hollow part 11 is formed in the main-body part 10m.

Furthermore, the upper surface of the first cushion body 10 gently rises from the rear toward the front, and the front edge portion 10f is formed with a thickness greater than that of the main body portion 10m. Thereby, the center of gravity of the seated person is shifted backward, and the weight is firmly supported by the main body 10m having high hardness.
Moreover, the 2nd cushion body 20 is comprised with the foam which consists of a polyurethane foam similarly to the 1st cushion body 10. FIG. And the upper surface of the 2nd cushion body 20 is formed in the substantially flat surface shape. On the other hand, the lower surface of the second cushion body 20 is formed so as to follow the shape of the recess 11, and has a convex portion 21 that is in close contact with the recess 11. That is, the lower surface of the second cushion body 20 is formed along the shape of the upper surface of the first cushion body 10 so as to fill the hollow portion 11 of the first cushion body 10.

  The epidermis 30 is composed of a jersey that simulates a suede fabric (hereinafter referred to as a suede-like jersey), and as shown in FIG. 4, stretch that follows the sinking of the second cushion body 20 when a person is seated. And a slip angle (grip rate) at which the seated person does not slip forward. Specifically, the suede jersey has an elongation of about 50% and a slip angle of about 40 °. The slip angle is an angle at which the test piece placed on the seat surface starts to slide when the seat surface is tilted, and is an index indicating the slipperiness of the seat or the grip force of the seat. is there. In addition, FIG. 4 shows, as a reference, the elongation rate and sliding angle of the skin made of various fabrics.

  Here, the skin 30 is formed so as to cover the upper surface of the second cushion body 20 and the side surface of the first cushion body 10, but at least only the upper surface of the second cushion body 20 is adhered and covered. It suffices if it is formed. That is, only the flat portion 3 of the seat 1 needs to be covered with the skin 30. At this time, the epidermis 30 is formed by integrally sueding a suede-like jersey and another appropriate fabric, and the side surface of the first cushion body 10 is covered with another appropriate fabric.

  Here, suede-like jersey is selected as the skin 30, and as described above, the elongation is set to about 50% and the slip angle is set to about 40 °. It is not limited, and it is only necessary that the fabric satisfies a good balance between an elongation rate that follows the sinking of the second cushion body 20 and a sliding angle that prevents the seated person from slipping forward. In particular, in order to follow the sinking of the second cushion body 20, it has been confirmed by experiments of the present inventors that the fabric needs an elongation rate of 30% or more. 4 and the slip angle may be any material that falls within the range enclosed by the circle in FIG. 4. As the skin 30, for example, birch knit may be selected.

<Molding method>
Hereinafter, a method for forming such a cushion structure for a seat will be described.
First, as shown in FIG. 5, a pair of molds including an upper mold 41 and a lower mold 42 are prepared. The upper mold 41 and the lower mold 42 are molds for molding the main body portion 10m of the first cushion body 10, and the shape of the space 43 formed by closing the upper mold 41 and the lower mold 42 is as follows. This corresponds to the three-dimensional shape of the main body 10m. More specifically, the inner surface 41a of the upper mold 41 has a shape corresponding to the bottom shape of the main body 10m. Further, the inner surface 42a of the lower mold 42 is formed with a protruding portion 42b for molding the hollow portion 11 because the upper surface of the main body portion 10m is molded on the surface thereof.

  Then, as shown in FIG. 6, a liquid foamable mixture 51 made of polyurethane foam adjusted and blended so as to become a highly elastic foam is introduced into the lower mold 42, and the upper mold 41 is closed and foamed. Then, the main body 10m is molded. Moreover, the front edge part 10f of the 1st cushion body 10 is shape | molded with the same method. At this time, a liquid foamable mixture made of polyurethane foam adjusted and blended so as to become a medium elastic foam is put into the mold (not shown). And the main body part 10m and the front edge part 10f which were molded in this way are adhered, and the first cushion body 10 of different hardness is molded (first step).

Next, as shown in FIG. 7, the liquid foamable mixture 52 made of polyurethane foam is poured into the entire area of the upper surface of the molded first cushion body 10 by, for example, a spray method and laminated (second step). The liquid foamable mixture 52 is blended so as to be a low-elasticity foam.
And as shown in FIG. 8, although the gas foaming of the liquid foamable mixture 52 has been completed, the upper surface of the liquid foamable mixture 52 and the side surface of the first cushion body 10 are removed in the reaction process in the viscoelastic flow state. The skin 30 is arranged so as to cover, the pressure mold 44 is lowered from above the first cushion body 10, and the skin 30 and the liquid foamable mixture 52 are compressed by the pressure mold 44 and the first cushion body 10. (Third step).

When foamed resin such as polyurethane foam reacts with the liquid foamable mixture to complete foam molding, it becomes a foam with stable and excellent elastic properties, and it does not deform easily even if it is compressed with pressure. .
However, it is a very unstable state in the reaction process, and within a certain time after the gas reaction is completed, the fluidity still remains and can be easily deformed by applying external force (viscoelastic flow State). Therefore, when this fluidity is applied together with a material such as another foam or fiber, it enters into another foam or part of the fiber structure, and the other foam or fiber is It adheres and becomes integral on the foam formed from the liquid foamable mixture. Further, when the compression ratio of the liquid foamable mixture is changed, the foam becomes hard at a high compression ratio and soft at a low compression ratio.

Therefore, when the liquid foamable mixture 52 is transferred to a solid state, the second cushion body 20 having a desired elasticity is molded, the skin 30 is formed on the upper side, and the first cushion body 10 is integrated on the lower side. The seat cushion structure of the present invention is completed.
<Action and effect>
The seat cushion structure according to the first embodiment of the present invention is configured as described above, and thus has the following operations and effects.

The seat 1 is configured with a two-layer cushion structure of the first cushion body 10 and the second cushion body 20, and further, the portion of the first cushion body 10 that is relatively hard is positioned at a portion where the sciatic bone mainly supporting the weight at the time of sitting is located. Since the depression 11 is formed on the upper surface, the thickness of the first cushion body 10 at the portion where the sciatica is located can be reduced.
And since the convex part 21 of a comparatively soft 2nd cushion body fits into the hollow part 11, and fills the hollow part 11, the thickness of the 2nd cushion body 20 of the part in which a sciatic bone is located can be made thick.

Therefore, the elasticity of the seat 1 where the sciatic bone is located becomes relatively small, the seating pressure (seat surface pressure) of the person seated on the seat 1 can be dispersed, and fatigue can be reduced well.
The demonstration of the effect of the seat pressure dispersion will be described with reference to FIGS. 9 (a) and 9 (b) and FIGS. 10 (a) and 10 (b).
FIGS. 9 (a), 9 (b) and 10 (a), 10 (b) show the seats averaged by 7 subjects in a situation setting in which a 6-axis vibration exciter was used for 2 hours on the Tomei Expressway. The measurement result of pressure distribution is shown.

As shown in FIG. 9 (a), when seated on a seat (hereinafter simply referred to as the main seat) formed of the seat cushion structure of the present invention, the seat pressure peak pressure is 95 g / cm ² immediately after seating. It has become. As shown in FIG. 9B, this is smaller than the peak pressure of 119 g / cm ² when seated on a seat formed of a conventional seat cushion structure (hereinafter simply referred to as a conventional seat).

When seated on the main seat, as shown in FIG. 10 (a), the peak pressure after the test (after running for 2 hours) is 125 g / cm ² , whereas when seated on the conventional seat, As shown in FIG. 10B, the peak pressure is 142 g / cm ² .
In addition, the conventional seat here refers to the seat formed with the two-layer cushion structure which does not have a hollow part shown in FIG. In addition, a symphony shown by a black square in FIG. 4 is used as the skin.

Therefore, it can be seen that the seating pressure of the seated person seated on the main seat is distributed as compared with the conventional seat.
Further, demonstration of the effect of fatigue will be described with reference to FIGS. 11 and 12.
Fatigue evaluation was conducted by interview with seven subjects in the above running test.
That is, 7 subjects are asked every 5-10 minutes from the start of the test (specifically, 5, 10, 15, 25, 30, 40, 45, 55, 60, 65, 70, 75, 85, 90, 100). , 105, 115, 120, 125 minutes) 19 times in total, as shown in FIG. 11, the fatigue level of the buttocks and lower back felt by the test subject was expressed as “1; not tired at all, 2; Somewhat tired, 4; tired, 5; quite tired, 6; very tired, 7; extremely tired. " Then, for each subject, the numbers of each time were integrated for a total of 19 times to obtain the degree of fatigue.

Then, as shown in FIG. 12, the degree of fatigue decreased when seated on the main seat 1 (in the case of point P ₁ ) compared to when seated in the conventional seat (in the case of point t ₁ ). In addition, while the vertical axis | shaft of FIG. 12 has shown the average value of the fatigue level of seven test subjects, the horizontal axis has shown the seat pressure.
That is, the degree of fatigue takes a value in the range of 7 to 133, and when it feels tired normally, it takes a value of 76 (standard fatigue value), but suede-like jersey is used as the skin 30. The value of the fatigue level of the subject seated on the main seat 1 decreased from the standard fatigue value.

Therefore, it can be seen that the seated person's fatigue can be satisfactorily reduced by sitting on the main seat 1 as compared with the conventional seat.
Here, in order to see the effect of the skin 30, the case where the skin 30 of the seat cushion structure using Birch knit, shown in Figure 12 two points P _2. Even in the case of the cushion structure for the seat using birch knit, the degree of fatigue was reduced compared to the conventional seat. However, when the skin 30 is composed of a suede-like jersey, it extends following the sinking of the second cushion body 20 when a person is seated, and the elasticity of the first cushion body 10 and the second cushion body 20 is reduced to the seat pressure. Can be reflected well. Further, the seated person has a sliding angle that prevents the seated person from slipping forward, so that the seated person can be prevented from slipping forward, can be seated stably, and fatigue can be further reduced.

In addition, since the elasticity of the front edge of the seat 1 is relatively small, the thigh is reduced from being compressed by the seat 1 while sufficiently supporting the weight of the seated person by the main body 10m of the first cushion body 10. can do.
This is particularly true when the seat cushion structure of the present invention is applied to the driver's seat of a vehicle such as an automobile, and the vibration applied to the vehicle travels from the foot to the whole body, but the soft front edge portion 10f absorbs the vibration, The transmission of vibration to the whole body can be suppressed to reduce driver fatigue. Further, since the thigh is difficult to be pressed by the seat 1, it is also effective in reducing fatigue related to the depression operation of the accelerator pedal or the brake pedal.

Furthermore, as a result of measuring the vibration characteristics of the main seat 1, as shown in FIG. 13, the vibration peak of the main seat 1 is far from 6 Hz, which is considered to affect the internal organs of the human body, compared to the vibration peak of the conventional seat. In addition, it was confirmed that there is an advantage that the amplitude at 6 Hz is small.
[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 14 is a cross-sectional view in the width direction of the cushion structure for a seat according to the second embodiment of the present invention. In addition, while using FIG. 3 used in description of 1st Embodiment suitably, it demonstrates, and the member same as the thing of 1st Embodiment is demonstrated with the same code | symbol as description of 1st Embodiment.
<Configuration>
2nd Embodiment differs in the structure which concerns on the convex part of a 2nd cushion body with respect to 1st Embodiment.

As in the first embodiment, the seat cushion structure of the second embodiment is applied to a seat 1 having a raised portion 2 and a flat portion 3 so as to wrap around the seated person's buttocks as shown in FIG. Yes.
As shown in FIG. 14, the seat cushion structure is disposed on the upper surface of the first cushion body 10 having the recess 11 and the first cushion body 10, and is less elastic than the first cushion body 10. A second cushion body 60 and a skin 30 that closely covers and covers the upper surface of the second cushion body 60 and the side surface of the first cushion body 10 are provided.

Further, as a feature of the second embodiment, it fits into the recess 11 and is sandwiched between the upper surface of the first cushion body 10 and the lower surface of the second cushion body 60 and is less elastic than the second cushion body 60. A cushion piece 70 is provided.
Therefore, in the second embodiment, the cushion piece 70 forms the convex portion of the second cushion body 60.
<Action and effect>
Since the seat cushion structure according to the second embodiment of the present invention is configured as described above, in addition to the effects described in the first embodiment, the following functions and effects are obtained.

The cushion piece 70, which is softer than the second cushion body 60, further reduces the elasticity of the seat 1 where the sciatic bone is located, disperses the seating pressure of the person seated on the seat 1, and reduces fatigue well. be able to.
Further, by changing the elasticity of the cushion piece 70, the dispersion of the seating pressure can be easily adjusted.

[Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the meaning of this invention.
For example, in the said embodiment, although the 1st cushion body 10 and the 2nd cushion body 20 are comprised by the foam which consists of polyurethane foams, you may replace with the foam which consists of other foamed resins, such as a polyurea foam. .

  Moreover, in the said embodiment, although the hollow part 11 provided in the 1st cushion body 10 was filled with the 2nd cushion body 20 or the cushion piece 70, as shown in FIG. You may shape | mold so that it may become the hollow space (cavity) S enclosed by the upper surface of the one cushion body 10, and the lower surface of the 2nd cushion body 20. FIG. Even in such a case, the elasticity of the seat 1 in the portion where the sciatica is located is further reduced, the seating pressure of the person seated on the seat 1 can be further dispersed, and fatigue can be reduced well.

Moreover, in the said embodiment, although the 1st cushion body 10 was shape | molded so that hardness might differ in the main-body part 10m and the front edge part 10f, as shown in FIG. 16, you may shape | mold with uniform hardness. Further, it may be molded so as to have a finer hardness.
Moreover, in the said 1st Embodiment, although the molding method of the cushion structure was demonstrated, the molding method of a cushion structure is not limited to this.

  In the first embodiment, as the third step, the pressure mold 44 is lowered from above the first cushion body 10, and the skin 30 and the liquid foamable mixture 52 are added by the pressure mold 44 and the first cushion body 10. For example, instead of the pressurizing die 44, a vacuum pressurizing die (not shown) having a plurality of suction holes on its pressurizing surface and having an external vacuum exhaust system connected to its internal space is used. The vacuum 30 and the liquid foamable mixture 52 are compressed and compressed by the vacuum pressurization mold and the first cushion body 10 in a state where the vacuum pressurization mold internal space is evacuated and the skin 30 is sucked onto the pressurization surface. Anyway.

Further, as the first step and the second step, the liquid foamable mixtures 51 and 52 made of polyurethane foam adjusted and blended so as to become foams of different hardness were filled. For example, the liquid foamable mixtures 51 and 52 The component blending ratio may be uniform, and the hardness of the cushion bodies 10 and 20 may be changed only by changing the compression ratio.
In each of the above embodiments, the case where the seat cushion structure of the present invention is applied to a vehicle seat such as an automobile has been described. However, the seat cushion structure of the present invention is also applied to various furniture seats and the like. It is possible.

It is width direction sectional drawing (AA sectional drawing of FIG. 3) which shows the cushion structure for seats concerning 1st Embodiment of this invention. It is a front-back direction sectional view (BB sectional view of Drawing 3) showing the cushion structure for seats concerning a 1st embodiment of the present invention. It is a perspective view showing a cushion structure for seats concerning a 1st embodiment of the present invention. It is a graph which shows the elongation rate and sliding angle of the skin of the cushion structure for seats concerning 1st Embodiment of this invention. It is a width direction sectional view showing the 1st process of the molding method of the cushion structure for seats concerning a 1st embodiment of the present invention. It is a front-back direction sectional view showing the 1st process of the molding method of the cushion structure for seats concerning a 1st embodiment of the present invention. It is width direction sectional drawing which shows the 2nd process of the molding method of the cushion structure for seats which concerns on 1st Embodiment of this invention. It is width direction sectional drawing which shows the 3rd process of the molding method of the cushion structure for seats which concerns on 1st Embodiment of this invention. It is a graph which shows the seating pressure distribution immediately after seating on a seat, (a) is the seating pressure distribution immediately after seating of the person seated on the seat formed with the cushion structure for seats concerning a 1st embodiment of the present invention. A graph (b) is a graph showing a seating pressure distribution immediately after the seating of a person seated on a conventional seat. It is a graph which shows the seating pressure distribution after seating on a seat and predetermined time progress, Comprising: (a) is predetermined time of the person seated on the seat formed with the cushion structure for seats concerning 1st Embodiment of this invention. The graph which shows the seating pressure distribution after progress, (b) is a graph which shows the seating pressure distribution after predetermined time progress of the person who seated on the conventional seat. It is a chart for evaluating the fatigue degree of the person seated on the seat formed with the cushion structure for seats concerning a 1st embodiment of the present invention. It is a graph which shows the relationship between the seating pressure of the person who seated on the seat formed with the cushion structure for seats concerning 1st Embodiment of this invention, and a fatigue degree. It is a graph which shows the vibration characteristic of the seat formed with the cushion structure for seats concerning a 1st embodiment of the present invention. It is width direction sectional drawing which shows the cushion structure for seats concerning 2nd Embodiment of this invention. It is width direction sectional drawing which shows the cushion structure for seats concerning other embodiment of this invention. It is a front-back direction sectional view showing a cushion structure for seats concerning other embodiments of the present invention. It is sectional drawing of the width direction which shows the cushion structure for seats concerning the prior art of patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seat 2 Raised part 3 Flat part 10 1st cushion body 10f Front edge part 10m Main body part 10s Side part 11 Recessed part 20 Second cushion body 21 Convex part 30 Skin 41 Upper mold 42 Lower mold 43 Space 51, 52 Liquid foaming property Mixture 60 Second cushion body 70 Cushion piece 100 Cushion body 101 First cushion body 102 Second cushion body 110 Skin material

Claims (4)

A cushion structure for a seat on which a person sits,
A first cushion body as a base;
A second cushion body that is disposed on the upper surface of the first cushion body and is less elastic than the first cushion body;
The upper surface of the first cushion body has a hollow portion that is gently curved downward and recessed in a portion where the sciatic bone of a seated person is located ,
The lower surface of the second cushion body is formed so as to conform to the shape of the recess, and has a convex portion that is in close contact with the recess.
The first cushion body is divided into two parts, a front edge portion and a main body portion in the front-rear direction,
A seat cushion structure characterized by high elasticity, medium elasticity, low elasticity and elasticity being formed in the order of the main body, the front edge, and the second cushion body . Fitted to the recess and sandwiched between the upper surface of the first cushion body and the lower surface of the second cushion body,
The cushion structure for a seat according to claim 1, further comprising a cushion piece that is less elastic than the second cushion body. An epidermis that adheres and covers the upper surface of the second cushion body;
The cushion structure for a seat according to claim 1 or 2, wherein the skin is made of a cloth having an elongation rate of 30% or more. The seat cushion structure according to claim 3 , wherein the skin is a jersey simulating a suede fabric .

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